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Definition of a Skeleton (brief characteristics of components the
skeleton). Functions of a Skeleton
Skeleton - is anatomical structure. It consists of bones, skeletal
cartilage, some periarticular tissues, bone marrow and liquids (blood, lymph and
intertissue liquid).
There are two parts in a skeleton:
- the axial part, including skull, vertebrae, ribs, breastbone, pelvis. It
surrounds and protects the important soft tissue - brain and spinal marrow, internal
organs;
- the supplimentary skeleton is the skeleton of extremities.
The functions of a skeleton are as follows: supporting,
protective, locomotor (support of the body in space), metabolic, bloodmaking.
The bone consists of bone tissue and is covered with periosteum,
involving bone marrow.
There are different types of bones: tubular they are short and long,
spongy (short), flat (wide), mixed and pneumatic.
Bone. Chemical Structure of Bone. Periosteum. Endosteum. Bone
marrow. Compact and Spongy Bones. Mechanical properties of Bones, their
Form and Peculiarities of the Structure
Bones are specialised type of connective tissue undergoing various
changes and consists of cells and solid intercellular substance containing calcium
salts.
Characteristics:
1. It is highly vascular
2. It is mineralised
3. It is hard and rigid and also somewhat resilient
4. It is constantly changing
5. It is regenerating capasity
6. It has a canalicular system for transport of nutrition
It may develop either by direct transformation of condenses mesenchyme or
through formation of a cartilaginous model which is later replaced by bone.
Functions:
1. It provides rigid structural framework of the body.
2. It provides area for attachment of muscles, and ligaments and also form a
lever for muscle movements.
3. It concerns protection of certain vital organs of body.
4. It contains bone marrow which manufactures blood cells.
5. It can act as store house for calcium and phosphorus.
Sructure of bone: Periosteum, Compact part, Spongy part, Medullary
cavity.
I. Periosteum – is a thick fibrous membrane covering the suface of bone
exept the articular surface. Structurally it consists of two layers: outer fibrous layer
consisting of white fibrous tissue, few osteoblasts and fat cells; inner
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II. osteogenetic layer consists of elastic fibers. It contains osteoblasts in
young bones and help in subperiosteal bone formation.
III. Compact Bone:
It is made of a number of cylindrical units called typical Secondary
Osteones or Haversian system which have a longitudinal orientation.
Each Haversian system consists of:
1.Haversian Canals – is a centrally located canals running parallel to long
axis of bone and contains nerves, blood vessels and lymphatics.
2.Concentric bony lamellae – It is made up of fine collagen bundles of
calcified matrix which surrounds the Haversian canal.
3.Lacunae- These are oval spaces between the lamellae and contain
osteocytes.
III.Spongy Bone: It consists of irregular trabeculae of bone with bone cells
but without any Haversian systems. They form large narrow spaces.
IY. Endosteum: It is a vascular membrane which lines the medullary
cavity and the spaces of bongy bone.
Y. Bone Marrow: It is a soft vascular tissue found in the medullary cavity
and spaces of spongy bone. Two types 1.Red – It is blood cell formation marrow
usually found in middle of young bone and in flat bones. In the adult red bone
marrow is contained in the bones of the skull, in the ribs, in the thorax, the
shoulder blade and clavicule, in the spine, in the pelvis bones, and a small quantity
of it can be found in tubular bones. Reticular tissue forms the basis of the bone
marrow. It is the predcessor of blood elements- leucocytes, erithrocytes, and
thrombocytes.2. Yellow (fatty) marrow- It is mostly fat.
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The histological structure of bone consists of two parts: 1.Bone cells, 2.
Intercellular substance or Matrix.
I Bone Cells: Osteoblasts, Osteocytes, Osteoclasts.
Osteoblasts – Bone forming cells. It is derived from undifferentiated
mesenchym. They secrete inorganic matrix around the cells. After ossification it
becomes matured and converted into osteocyte.
Osteocytes – Matured bone-cells.They have flattened body whith multiple
processes and live for 25 years. It get renewed every year in compact bone 2-2,5%,
in spongy bone - up to 10 % of cells.
Osteoclasts – Bone destroying cells.
II. Intercellular substance:
1. Organic – collagen fibes and cement substence.
2. Inorganic – important elements as bone salts – Calcium, magnesium,
phosphate, carbonate, fluoride and citrate.
Different types of Bone:
I.
Long Bone. They have two ends: Epiphysis and one shaft-
Diaphysis They are covered with cartilage and serve for connection with other
bones. The part between diaphysis and epiphysis is called metaphysis. On a surface
of bone foramina nutricia are located. ( Humerus, radius, ulna, femur,tibia and
fibular.)
I. Short Bones ( examples are Carpals and Talus).
II. Flat Bones- plate-like and actually consists of two outer plates of
compact bone within which lie spongy bone and marrow.( examples are scapula,
sternum, ribs, and bones of vault of scull.
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III. Pneumatic Bones: Special type of irregular bones containing air sinus,
i.e. air filled spaces within it. Examples: Maxillar, Frontal, Sphenoid and Ethmoid.
IV.Sesamoid Bones: are those bones which are formd in the tendons of
muscles.
Mechanical characteristics of the bone. The bone is a very strong
tissue. It is capable of maintaining large mechanical loads. It is experimentally
proved, that the tension strenght of the bone is 10-12 кg per mm2, and compression
strength is 12-16 кg per mm2. The bone is 5 times as strong as concrete, and is
well adapted to various loads.
Development and growth of theBones
The skeleton develops from germ connective tissue - mesenhima.
Then the large part of the skeleton becomes cartilaginous. Then cartilage is
destroyed and becomes the bone. In this way the bones of the body, extremities
and the basis of the scull are developted. The bones of the fornix of the scull and
some face bones develop insted of mesenchimal germ. They are called connective
tissue. Such as parietalis,
frontalis, occipitalis, squama and tympany of temporalis bone, and also
lacrimalis, nasalis , and vomer.
The process оf the bone ossification begins with the formation of
ossification points, where the centres of future bones are located.
The development and growth of the bones in the place of the
cartilage occurs at the process of periosteal and enhondral ossification.
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The growth of the bone in length take place from metaphysis. In the
end of growth of the body the cartilage is completely оssified. Growth in width
take place by appositional growth and subperiosteal bone deposition occurs in
succesive layer.
Factors for Bone growth
I.Metabolic factors: 1.Diet – should consist of calcium, phosphorous 2.
Hormonens
II. Genetic factors
III. Mechanical factors
Аge features of the bone
The skeleton is a very labile formation. It adopts to physical loads
increased and its structure changes.
Many human bones are originated and developed as several parts.
Then they are joined and form a single bone. For example, pelvis develops as
three big parts: pubis, ischii, ileum.
The bones of the skull are originally
separeted bordered with the sutures and then become closed..
In children up to 4-5 years of age only red bone marrow can be found
in the bone-marrow chanel.
In the course of years the content of mineral substances increase
resulting in their fragility. The connection of the bones to occurs the skull bone
sutures close, red bone marrow in tubular bone channels becomes yellow. The
bones become
lighter and atrophied because of the decrease muscle extertion. Thus, to
maintain physical condition one should do physical exercises throughout his life.
Lecture № 2
Functional Anatomy of the Skull. Development of the Skull. Age and
Sexual Features of the Skull
The plan of lecture:
1. The Skeleton of the Head.
2. Development of the Skull.
3. Connection of the Skull s bone.
4. Age features of the Skull.
5. Anterior, Lateral, Posterir, Superoir Aspects of the Skull. External
and Internal Aspects of the Cranial Base.
The Skeleton of the Head
The skull ( or cranium in Latin) is the skeleton of the head.It consists of two
parts, the neurocranium and fasial skeleton. The neurocranium (“brain box” or
cranial vault) provides a case for the brain and cranial meninges. The facial
skeleton consists of the bones surrounding the mouth and nose and contributing to
the orbits (eye sockets, orbital cavites).
The neurocranium in adults is formed by a series of eight bones:

a frontal bone;

two parietal bones;

two temporal bones;

an occipital bone;

a sphenoid bone;

an ethmoid bone.
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The facial skeleton consists of 14 bones:

lacrimal bones (2);

nasal bones (2);

maxillae (2);

zygomatic bones (2);

palatine bones (2);

inferior nasal conchae (2);

mandible (1);

vomer (1).
The cranium has a domelike roof – the calvaria (skullcap) – and a floor or
cranial base (basicranium) consisting of the ethmoid bone and parts of the occipital
and temporal bones.
Most of these bones are largely flat, curved, and united by fibrous
interlocking sutures. These bones are composed of two layers of compact tissue
enclosing between them a variable quantity of cancellous tissue.In the cranial
bones the outer layer is thick and tough, the inner one thinner, denser and more
brittle. The intervening cancellous tissue is called diploe.
In the anatomical position, the skull is oriented so that the inferior margin of
the orbit and the superior margin of the external acoustic meatus of bouth sides lie
in the same horizontal plane. This standard craniometric reference is the
orbitomeatal plane.
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Development of the Skull
The bones forming the calvaria and some parts of the cranial base
develop by intramembranous ossification. These bones is called primary bones.
Whereas most parts of the cranial base develop by endochondral ossification. Thus
bones are called secondary bones.
Stage of Intra Membranous Ossification
1. Condensation of mesenchyme.
2. Mesenchymal cells differentiate into osteoblasts.
3. Osteoblasts proliferate and produce collagen fibres and hyaline matrix.
4. Finally calcium salts are deposited and the surrounding mesenchyme is
differentisted into periosteum.
5. Process continues by surface subperiosteal bone formulation by
osteoblasts and bones thus formed extends radially forming trabeculated bone.
6. At first Trabeculated bone joint together forms cancellous then Lamella
is formed by addition of fresh bones to Trabeculated bone. Finally, deposition of
fresh lamellae converts the cancellous into compact bone.
Intra Cartilaginous Ossification
In this type of ossification at first mesenchyme is condensed and converted
intocartilaginous models. Then this cartilaginous model is destroyed and bone is
formed by replacing gradually the degenerated remains of the model.
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Conections of bones of skull
The bones of the skull, with the exeption of the Mandible are connected to
each other by means of Sutures. That is the articulating sufaces of the bones are
more or less roughened or uneven and are closely adapted to each other.
The sutures at the vertex of the skull are four: sagittal, coronal, lambdoid and
sguamous.
1. The Sagital Suture is formed by the junction of the two parietal bones.
2. The Coronal Suture extends transversely across the vertex of the skull
and connects the frontal with the parietal bones.
3. The Lambdoid S. so called from its resemblance to the Greek latter
,
connects the occipital with the parietal bones
4. The Squmous S is the joints between squamous part of temporal bone
and parietal bone.
The mandible connected with the skull
movable and forms the
temporomandibular joints.
Age features of the Skull
At birth, the bones of the calvaria are smooth and unilaminar; no diploe is
present. The frontal and parietal eminences are especially prominent. The skull of a
newborn infant is disproportionately large compared with other parts of the
skeleton; however, the facial skeleton is small compared with the calvaria, forming
approximately one-eighth of the skull; in the adult the facial skeleton forms
one-third of the skull. The large size of the newborn s calvaria results from
precocious
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growth and development of the brain. The smallness of the face results from
the maxillae, mandible, and paranasal sinuses (cavities in facial bones), the
absence of erupted teeth, and the small size of the nasal cavities. The rudimentary
development of the face makes the orbit appear relatively large.
Observe that the halves of the frontal bone are separated by a frontal
suture but the greater part of it usually disappeared about the 15 or 16 year.The
maxillae and mandibles are separated by an intermaxillary suture and mandibular
symphysis, respectively.
At an early period of life a thin plate of cartilage exists between the
basilar surface of the body of the occipital bone and the posterior surface of the
body of the sphenoid. In the adult they become fused and the basilar suture is
formed.
The bones of the calvaria of a newborn infant are separated by areas of
fibrous tissue membrane – the fontaneless – which represent parts of unossified
bones. There are six fontanelles : two are in the median plane – anterior and
posterior – and two pairs are on each side – the anterolateral or sphenoidal fon. and
the posterolateral or mastoid fon.
The anterior fon. is located at the junction of the sagital, coronal, and
frontal sutures, the future site of the bregma. By 18 months of age, the surrounding
bones have fused and the anterior fon. is no longer clinically palpable. Union of the
halves of the frontal bone negins in the 2nd year. In most cases , the frontal suture is
obliterated in the 8th yaer.
The posteror fon. is triangular and bounded by the parietal bones anteriorly
and occipital bone posteriorly. It is located at the junction of the lambda. The
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posterior fon. begins to close during the first few months after birth, and by
the end of the 1st year it is small and ano longer clinically palpable.
The resilience of the bones of the fetal skull allows it to resist forces
that would produce a fracture in adults. The fibrous sutures of the calvaria also
permit the skull to enlarge during infancy and childhood. The increase in the size
of the calvaria is greatest during the first 2 years, the period of most repid brian
development. A person s calvaria normally increases in capacity until 15 or 16
years of age.
Anterior, Lateral, Posterir, Superoir, External and Internal Aspects of
the Skull
Anterior Aspect of the skull.
Features of anterior aspect of the skull are the frontal and zygomatic
bones, orbits, nasal regon, maxillae, and mandible.
The frontal bone- specifically its squamous part – forms the skeleton
of the forehead, articulating inferiorly with the nasal and zygomatic bones. The
supraorbital margin, the angular boundary between the squamous and orbital parts,
has a supraorbital notch or a foramen in some skulls for passage of the supraorbital
nerve and vessels. Just superior to the supraorbital margin is a ridge – the
superciliare arch – that extends laterally on each side from the glabella. The
prominence of this ridge, deep to the eyebrows, is generally greater in males.
Within the orbits are the superoir and inferior orbital fissures and optic canals.
The maxillae form the upper jaw; their alveolar processes include the
sockets (alveoli) and constitute the supporting bone for the maxillare teeth. The
maxillae
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have a broad connection with the zygomatic bones laterally and have an
infraorbital foramen inferior to each orbit for the infraorbital nerve and vessels.
The mandible consists of a horizontal part, the body, and a vertical
part, the the ramus. The mandible is a U-shaped bone with alveolar processes that
hous the mandibular teeth. Inferior to the second premolar teeth are the mental
foramina for the mental nerve and vessels. The mental protuberanse – forming the
prominence of the chin – is a triangular elevation of bone inferior to the
mandibular symphysis, the region there the halves of the fetal mandible fuse.
Lateral Aspect of the Skull.
The lateral aspect of the skull is formed by cranial and facial bones.
The main features of the cranial part include the temporal fossa, the opening of the
external acoustic meatus, and the mastoid region of the temporal bone. The main
features of
the facial part include the infratemporal fossa, zygomatic arch, and lateral
aspects of the maxilla and mandible. The temporal fossa is bounded superiorly
and posteriorly by the temporal lines, anteriorly by the frontal and zygomatic
bones, and inferiorly by the zygomatic arch.
The external acostic meatus opening is the entrance to the external
acoustic meatus, which leads to the tympanic membrane. The mastoid proces of
the temporal bone is posteroinferior to the opening of the external acoustic meatus.
Anteromedial to the mastoid process is the slender styloid process.
Posterior Aspect of the Skull.
The posterior aspect of the skull, or occiput, is typically ovoid or
round in outline. It is formed by the occipital bone, parts of the parietal bones,
and mastoid parts of the temporal bones. The external occipital protuberance is
usually an easily
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palpable elevation in the median plane. The external occipital crest descends
from the external occipital protuberance toward the foramen magnum – the large
opening
in the basal part of the occipital bone. The superior nuchal line, marking the
superior limit of the neck.In the center of the occiput, the lambda indicates the
junction of the sagittal and lambdoid sutures.
Superior Aspect of the Skull.
The superior aspect of the skull, usually somewhat oval in form,
broadens posterolaterally at the parietal eminences. The coronal suture separates
the parietal bones, and the lambdoid suture separates the parietal and temporal
bones from the occipital bone.The bregma is the landmark formed by the
intersection of the sagittal and coronal sutures. The vertex – the most superoir
point of the skull – is near the midpoint of the sagittal suture.
The inferior region or base of the skull presents two surfaces an
external or basilar and internal or cerebra.
External Aspect of the Cranial Base.
The external surface of the cranial base shows the alveolar arch of the
maxillae, the palatine processes of the maxillae, and the palatine, sphenoid, vomer,
tenporal, and occipital bones.
Wedged between the frontal, temporal, and occipital bones is the
sphenoid bone, consists of the body, greater wings, lesser wings, and pterygoid
process. Depression in the temroral bone – the mandibular fossae – accommodate
the condyles of the mandible when the mouth is closed.
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The cranial base is formed posteriorly by the occipital bone, which
articulates with the sphenoid bone anteriorly. The large opening between the
occipital bone and the petrous part of the temporal bone is the jugular foramen,
from which the internal jugular vein and several cranial nerves emerge from the
skull. Superolateral to the
jugular foramen is the internal acoustic meatus.The entrance to the carotid
canal for the internal carotid artery is just anterior to the jugular foramen. The
mastoid process is ridged because it is designed for muscle attachment. The
stylomastoid foramen, transmitting the facial nerve and stylomastiod artery, lies
posterior to the base of the styloid process.
Internal Aspect of the Cranial Base.
The internal surface of the cranial base has three large, depressions
that lie at different levels – the anterior, middle, and posterior cranial fossae –
which form the bowl-shaped floor of the cranial cavity.
Anterior Cranial Fossa. The inferior and anterior parts of the frontal
lobes of the brain occupy the anterior cranial fossae, the shallowest of the three
fossae. The anterior cranial fossa is formed by the frontal bone anteriorly, the
ethmoid bone in
the middle, and the body and lesser wings of the sphenoid posteriorly. The
crista galli ( cock , s comb) is a median ridge of ethmoid bone. The foramen
caecum is anterially to the cock , s comb.
Middle Cranial Fossa. The middle cranial fossa is butterfly-shaped,
composed of large, deep depressions on each side of the much smaller sella turcica
centrally on the body of the sphenoid bone. The boundary between the middle and
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posterior cranial fossae is the petrous crests of the temporal bones laterally
and a flat plate of bone, the dorsum sellae of the sphenoid, medially.
The sella turcica ( Turkish saddle)– is composed of three parts:

tuberculum sellae;

hypophyseal fossa;

dorsum sellae (“back of the saddle”).
In the middle cranial fossa on each side of the base of the body of the
sphenoid bone is a crescent of four foramina:

the superor orbital fissure is between the greater and lesser
wings. This fissure transmits the ophtalmic veins and nerves entering the orbit;

the foramen rotundum, it transmits the maxillary nerve;

the foramen ovale, it transmits the mandibular nerve;

the foramen spinosum, it transmits the middle meningeal vessels
and the meningeal branch of the mandibular nerve.
The foramen lacerum – not part of the crescent of foramina – is a ragged
foramen that lies posterolateral to the hypophysial fossa; it is an atrifact of a dried
skull.
Posterior Cranial Fossa.
The posterior cranial fossa lodges the cerebellum, pons, and medulla
oblongata. The posterior cranial fossa is formed largely by the occipital bone, but
the dorsum sellae of the sphenoid marks its anterior boundary centrally
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and the petrous and mastoid parts of the temporal bones contribute its
anterolateral “walls". From the dorsum sellae, the clivus is a marked incline in the
center of the anterior part of the posterior cranial fossa leading to the foramen
magnum.
Lecture №3
The Structures Composing the Joints. Classification of Joints.
Plan of the Lecture:
1. The Structures Composing the Joints.
2. Classification of the Joints.
3. The Kinds of Movement admitted in Joints.
4. Different Kinds of the Joints.
The various bones of the Skeleton are connected together at different
parts of their surfaces, and such a connection is designated by the name of Joint or
Articulation. If the Joint is immovable as between the cranial and most of the facial
bones, the adjacent margins of the bones are applied in almost close contact, a thin
layer of fibrous membrane, the sutural ligament, and at the base of the skull. But in
certain situations, a thin layer of cartilage is interposed.Where slight movement is
required, combined with great strength, the osseous surfaces are united by tough
and elastic fibro-cartilages, as in the joints between the vertebral bodies and in the
interpubic articulation. But in the movable joints, the bones forming the
articulation are generally expanded for greater convenience of mutual connection,
covered by cartilage, held together by strong bands or capsules of fibrous tissue,
called ligaments, and partially lined by a membrane, the synovial membrane,
which secrets a fluid to lubricate the various parts of which the joints is formed: so
that the structures which enter into the formation of a movable joint are bone,
cartilage, fibro-cartilage, ligament, and synovial membrane.
And so, a joint is an articulation – the place of union or junction
between two or more bones or parts of bones of the skeleton. Joints exibit a variety
of form and functions. Some
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joints have no movement; others allow only slight movement, and some are
freely movable, such as the shoulder joint.
The three types of joint are classified according to the maner or type of
material by which the articulating bones are united.
Classification of the Joints
The articulations are divided into three classes: synarthrosis, or immovable;
amphiarthrosis, or mixed; and diarthrosis, or movable joints.
1. Synarthrosis. Immovable Articution.
Synarthrosis includes all those articulationis in which the surfaces of the
bones are in almost direct contact, fastened together by an intervening mass of
connective tissue or hyaline cartilage, and in which there is appreciable motion, as
the joints between the bones of the cranium and face, excepting those of the lower
jaw.
Sutura (a seam) is that form of articulation where the contiguous margins
of flat bones are united by a thin layer of fibrous tissue. It is met with only in the
skull. When the articulating surface are connected by a series of processes and
indentations interlocked together, it is termed a true suture ( sutura vera); of which
there are three varieties: sutura dentata, serrata, and limbosa.
Gomphosis (a nail) is an articulation formed by the insertion of a conical
process into a socket, as a nail is driven into a board; this is not illustrated by any
articulation between bones, properly so called, but is seen in the articulation of the
teeth with the alveoli of the maxillary bones.
Synchondrosis.-Where the connecting medium is cartilage the joint is
termed a synchondrosis. This is a temporary form of joint, for the cartilage
becomes converted into
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bone before adult life. Such a joint is found between the epiphyses and
shafts of long bones, and in the junction between the occipital bone and the
sphenoid and between the petrous portion of the temporal bone and the jugular
procces of the occipital bone.
2. Amphiarthrosis. Mixed Articulations.
In this form of articulation only a slight amount of movement is
possible, the contiguous osseous surfaces being either connected together by
broad flattened discs of fibro-cartilage, of a more or less complex structure, which
adhere to each bone, as in the articulation between the bodies of the vertebrae, and
in the pubic symphysis. This is termed Symphysis. Or, secondly, the bony surfaces
are united by an interosseous ligament, as in the inferior tibio-fibular articulation.
To this the term Syndesmosis is applied. The interosseus membrane is the forearm
is a sheer of fibrous tissue that joint the radius and ulna is a syndesmosis.
3. Diartrosis. Movable Articulations or Synovial joints.
This form of articulation includes the greater number of the joints in the
body, mobility being their distinguishing character. They are formed by the
approximation of two contiguous bony surfaces, covered with cartilage, connected
by ligaments, and lined by synovial membrane.
The synovial joints – name – comes from the labricating substance
(synovial fluid) that is in the joint cavity or synovial cavity, which is lined with a
synovial membrane consists of vascular connective tissue that produces synovial
fluid (fig. 1).
The three distinguishing features of a synovial joint are:

a joint cavity;

bone ebds covered with articular cartilage;

articulating sufaces and joint cavity enclosed by an articular
capsule (fibrous capsule lined with synovial membrane).
Synovial joints are usually reinforced by accessory ligaments that are
either separete (extrinsic) or are a thickening of a portion of the articular capsule
(intrinsic).
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Some synovial joints have other distinguishing features such as
fibrocartilating articular disc, which are present when the articulating surfaces of
the bones are incongruous.
The six major types of synovial joint are classified according to the
shape of the articulating surfaces and (or), the type of movement they permit.
Plane joints (for exsampule the acromioclavicular joint between the
acromin of the scapula and the clavicle) are numerous and are nearly aways
small. They permit gliding or sliding movements. The opposed sufaces of the
bones are flat or almost flat. Most plane joints allow movement in only one plane
(axis); hence joints uniaxial joints. Movement of plane joints is limited by their
tight articular capsules.
Hinge joints move in one plane (sagittal) around only one axis
(uniaxial) that runs transversely between the bones involved (the elbow joint).
Hinge joints permit flexion and extensoin, only. The artiular capsule of these joints
is thin and lax anteriorly and posteriorly where movement occurs; however, the
bones are joined by strong, laterally placed collateral ligaments.
Sadlle joints are biaxial with opposing surfaces shaped like a saddle.
The carpometacarpal joint at the base of the 1st digit (thumb) is a saddle joint.
Codyloid joints are also biaxial and allow movement in two planes,
sagittal and frontal (coronal) (the metacarpophalangeal joints); however,
movement in one axis (sagittal) is usually greater (freer) than in the other. Their
two axes lie at right angles to each other. Condyloid joints permit flexion and
extension; abduction and adduction, and circumduction.
Ball and socket joints are multiaxial (polyaxial); they move in multiple
axies and in mulitple planes. In these highly movable joints (the hip joint), the
spheroidal surface of one bone moves within the socket of another (the head of the
femur in the acetabulum of the hip bone). Flexion and extension, abduction and
adduction, medial and lateral rotation, and circumduction can occur at ball and
socket joints.
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Pivot joints are uniaxial and allow rotation. In these joints, around
process of bone of bone rotates within a sleeve or ring. Examples include the
rotation of the radius during pronation and supination of the atlas (C1 vertebra)
around the dens (odontoid process) of the axis (C2 vertebra) during rotation of the
head at the atlantoaxial joint.
The Kinds of Movement admitted in Joints
The movements admissible in joints may be divided into four kinds:
gliding, angular, circumduction, and rotation. However, these movements are
often, more or less combined in the various joints, so as to produce an infinite
variety, and it is seldom that we find only one kind of motion in any particular
joint.
Gliding movement is the simplest kind of motion that can take place in
a joint, one surface gliding or moving over another without any angular or rotatory
movement.
Angular movementjccurs only between the long bones, and by it the
angle between the two boners is increased or diminished. It may take place in four
directions: forwards and baskwards, constituting flexion and extension, or inwards
and outwards, from the mesial line of the body, constituting adduction and
abduction.
Circumduction is that degree of motion which takes place between the
head of a bone and its articular cavity, while the limb is made to circumscribe a
conical space, the base of which corresponds with the inferior extremity of the
limb, the apex with the articular cavity; this kind of motion is best seen in the
shoulder-and hip-joints.
Rotation is the movement of a bone around an axis; the latter may
be formed by a separate bone, as in the case of the pivot formed by the odontoid
process of the axis around which the atlas; or a bone may rotate around its own
longitudinal axis, as in the rotation of the
6
humerus and femur at the shoulder-and hip-joints respectively and other.
Such movements are called supination and pronation.
Different Kinds of the Joints
Joints of the Vertebral Bodies.
The human vertebral column has all types of joints: syndesmoses (lig.between the
transverse and spinous processes), synchondroses (between the bodies of vertebra),
synostoses (between the sacral vertebrae), hemiarthroses (between the bodies of series of
vertabrae) and diarthrosis (between the articular processes).
The vertebral bodies forming the vertebral column proper which supports the trunk
unite one with another (and also with the sacrum) by means of, synchondroses called
intervertebral cartilages or discs or by means of hemiarthroses if there are clefts between
them.
Each IV disc consists of:
 An anulus fibrosus – an outer fibrous part – composed of concentric
lamellae of fibrocartilage;
 A gelatinous central mass – the nucleus pulposus.
There are two ligaments in the joints of the vertebral bodies: the anterior
longitudinal lig. Is a strong and connects the anterolateral aspects of the vertebral
bodies and IV discs.The posterior longitudinal lig. It runs within the vertebral
canal along the posterior aspect of the vertebral bodies.
Joints of the Vertebral Arches.
These articulations are plane synovial joints between the superior and
inferior articular processus of adjacent vertebrae.
Ligaments of the intervertebral joints are as follows: 1)the spaces
between the arches are filled by elastic fibers of yellow colour, which are therefore,
called yellow ligament (ligamentum flava); 2) the interspinous lig. Between the
spinous prosesses, 3)the supraspinous lig.which is streched over the apices of the
spinous processes, 4)the intertransverse lig. are
the ligaments between the
transverse processes.
Temporomandibular Joint (TMJ).

The TMJ is a modified hinge type of joint. It is formed by the head
of the mandible, the articular tubercle of the temporal bone, and the mandibular
fossa. The articular capsule of the TMJ is loose. The articulating surfaces are
complemented by a fibrous articular disc. The articular disk divides the joint into
two separate compartments. The thick part of the articular capsule forms the
intrinsic lateral ligament (ligamentum temporomandibularis), which strengthens
the TMJ laterally and, with the postglenoid tubercle, acts to prevent posterior
dislocation of the joint.
Two extrinsic ligaments and the lateral ligament connect the
mandible to the cranium. The stylomandibular ligament – runs from the styloid
process to the angle of the mandible. The sphenomandibular ligament runs from
the spine of the sphenoid to the lingula of the mandible.
The movements of the mandible at the TMJ are as follows:
Depression (open mouth), Elevation (closed mouth), Protrusion (protraction of
chin).
Joints of the Upper Limb.
1. Shoulder Joint
The GJ is a ball-and-socket type of synovial joint that permits a wide
range of movement; however the mobility it the relatively unstable. The large,
round humeral head articulates with the relatively shallow glenoid cavity of the
scapula. On the circumference of the cavity is a fibrocartilaginous glenoid lip
(labrum glenoidale). The fibrous capsule of the shoulder joint is free and thin. Only
one ligament in the shoulder joint. It is the coracohumeral ligament. It is very well
from one side, conducive to the wide range of movement at the shoulder joint
necessary for the functioning of the limb as an organ of labour. On the other hand,
the weak fixation of the shoulder joint is the cause of frequent dislocations.
Movements of the GJ: Flexion-extensjon, abduction-adduction,
rotation, circumduction.
Elbow Joint (EJ).
The EJ(articulatio cubiti) – a hinge type of synovial joint. Three
bones articulate in the elbow joint, so it is compound joint. The articulating bones
form three joints invested in a common capsule: the humeroulnar articulation, the
humeroradial art. And the proximal radioulnar art. The articular capsule is weak
anteriorly and posteriorly but is strengthened on each side by collateral ligaments.
Ligaments of the EJ are the radial collateral lig. and the ulnar
collateral lig and anular ligament of the radius.
Movements of the EJ are flexion and extension. Pronation and
supination are in proximal and distal radio-ulner joints.
Wrist Joint.
The wrist joint (radiocarpal) is a condiloid type of synovial joint. It is
formed with carpal articular surface of the radius, the proximal surface of the first
row of carpals bones, except for the pisiform, and cartilaginous disc, instead of
ulna. According to the number of bones forming it, the joint is compound and the
complex. According to the shape of articular surfaces, it is an ellipsoid joint with
two pivotal axes.
Ligaments of the wrist joint are the palmar radiocarpal lig., the dorsal
radiocarpal lig., ulnar collateral lig., radial collateral lig.
Movements
of
the
wrist
joint
are
flexion-extension,
abduction-adduction and circumduction.
Joints of the Lower Limb.
Joints of the pelvic bones:
1. The sacro-iliac joint (art. sacroiliaca) is formed by the contiguous
auricular surfaces of the sacrum and ilium. These surfaces are congruous and
covered by а thin layer of fibrous cartilage. The sacrum is wedged between the two
iliac bones, as а result of which it cannot be displaced anteriorly and downward by
the weight of the trunk until the bracings of the pelvic vault are separated; the
sacrum is therefore the key of the pelvis (Lesgaft). This key is strengthened by
many ligaments:the interosseous sacro-iliac ligaments (ligamenta sacroiliaca
interossea) the anterior sacro- iliac ligaments; the posterior sасго-i1iас
ligaments (ligamenta sacroiliaca dorsalia); the iliolumbar ligament (lig.
iliolumbale).
2. The pubic symphysis (symphysis pubica) is on the midline and joins the
pubic bones. А fibrocartilaginous plate, the interpubic disc (discus interpubicus)
is lodged between the facies symphysialis of these bones, which face each other
and are covered with hyaline cartilage. А narrow synovial slit-like cavity is seen in
this disc nearer to its posterior surface (hemi arthrosis) usually from the age of 7
years.
3The sacrotuberal and sacrospinal ligaments are two strong interosseous
ligaments connecting on each side the hip bone with the sacrum. The
sacrotuberous ligament (lig. sacrotuberale) stretches from the ischial tuberosity
tо the lateral borders of the sacrum and coccyx. The sacrospinaI ligament (lig.
sacrospinale) originates at the ischial spine, crosses the sacrotuberal ligament, and
is attached to the lateral border of the lower part of the sacrum and the upper раrt
of the coccyx. The ligaments boudary two foramens: f. Ischiadicum major et
minor.
4. The obturator membrane (membrana obturatoria) is а fibrous plate
closing the obturator foramen of the pelvis except in its superolateral part. It is
attached to the edge of the obturator sulcus of the pubis found here and thus
converts this sulcus to the obturator canal transmitting obturator vessels and
nerves.
1.Hip Joint.
The hip joint forms the connection between the lower limb and the pelvis
girdle. It is a strong and stable multiaxial ball – and socket type of synovial joint –
the femoral head is the ball and the acetabulum is the socket. The depth of the
acetabulum is increased by the fibrocartilaginous acetabular labrum, which
attaches to the bony rim of the acetabulum and the transverse acetabular lig., more
than half of the head fits within the acetabulum. The central and inferior part of the
acetabulum, the acetabular fossa, is thin, nonarticular, and often translucent.
The ligaments of the hip joint are as follows: the iliofemoral lig.; the
pubofemoral lig.; the ischiofemoral lig.; the lig. of the head of the femur.
Movements of the hip joint are as follows: flexion, extension,
abduction, adduction, rotation.
2. Knee Joint (KJ).
The articular surfaces of the KJ are characterized by the large size and
their complicated and incongruent shapes. The KJ consists of three articulations:
 lateral and medial articulations between the femoral and tibial condyles;
 intermediate articulation between the patella and femur.
The fibula is not involved in the KJ.
Extracapsular Ligaments of the Knee Joint. The fibrous capsule is
strengthened by five extracapsular lig.: the patellar lig., the tibial collateral lig., the
fibular collateral lig., the oblique popliteal lig., the arcuate popliteal lig.
Intracapsular Ligaments of the Knee Joint: there are two cruciate
ligaments in the KJ - anterior and posterior. The cruciate ligaments are located in
the center of the joint and cross each other obliquely like letter X, providing
stability to the KJ. The coronary lig. are capsular fibers that attach the margins of
the menisci to the tibial condyles, and also transverse lig. of the KJ.
There are two menisci in the KJ: the medial men. and lateral men. The
menisci of the KJ are crescentic plates of fibrocartilage on the articular surface of
the tibia that deepen the surface and act like shock absorbers. The Greek word
meniskos means crescent.
Movements of the KJ: flexion, rotation, extension.
3. Ankle Joint (AJ) .
The ankle joint (talocrural articulation) is located between the distal
ends of the tibia and fibula and the superior part of the talus. The tibia
articulates with the talus in two places:
 its inferior surface forms the roof of the joint;
 its medial malleolus articulates with the medial surface of the talus.
 Lateral malleolus articulates with the lateral surface of the talus.
Ligaments of the AJ: the lateral lig. consists of the anterior talofibular lig.,
the posterior talofibular lig., and the calcaneofibular lig. Medial lig.(deltoid lig.)
consists of tibionavicular lig., anterior and posterior tibiotalar ligg. and
tibiocalcaneal lig.
Movements of the AJ: dorsiflexion, plantarflexion.
The joints of the foot contents two main articulations: the transverse
tarsal joint (art. Tarsi transversa) or Chopart,s joint and tarsomatatarsal joints (art.
tarsometatarsae) or Lisfranc,s loints. Chopart,s j. Is compound j. It consists of two
joints: art. Calcaneocuboidae and art. Talonaviculare. This j. Is reinforced with lig.
bifurcatum. It is a common lig. to both these joints which is of great practical
importance. This short but strong lig. is the key to Chopart,s joints during an
operation for the exarticulation of the foot at this joint.
Lisfranc,s joint is formed with the articular surfaces on the distal
aspect of the three cuneiform bones and the cuboid bone and five metatarsal bones.
This joint is typical tight joint. It is strengthened with dorsal plantar and
interosseus ligaments.
Lecture №5
Muscles and Fasciae of the Head and Neck. Triangles of the Neck
Plan of the Lecture:
1. Muscles of the Face:
a) Chewer Muscles
б) Mimic Muscles
2. Superficial and Lateral Muscles of the Neck.
3. Deep Structures of the Neck.
4. Triangles of the Neck.
5. Fascia of the Neck.
Muscles of the head are divided into two groups:
1.Muscles of mastication: derivatives of the first visceral (mandibular)
arch. Innervation: nervus trigaminus.
2.Muscles of facial expression:derivatives of the second visceral (hyoid)
arch. Innervation: nervus facialis.
Muscles of Mastication
The 4 muscles of mastication on each side are related genetically (they
originate from a single visceral arch, the mandibular arch), morphologically (they
are all attached to the mandible which they move when they contract) and
functionally (they accomplish the chewing movements of the mandible, which
determines their location).
The Masseter – is a short thick muscle consisting of two portions:
superficial and deep.It arises from the inferior border of the zygoma and zygomatic
arch and is attached to the masseteric tuberosity and the external surface of the
mandibular ramus.
The Temporal – is a broad radiating muscle, situated at the side of the head
and occupying the entire extend of the temporal fossa. It is atteched to the coronoid
process of the mandible.
The lateral pterygoid – is a short, thick muscle somewhat conical in form,
which extends almost horisontally between the zygomatic fossa and the condyle of
the jaw. It is arises from the inferior surface of the greater wing of the sphenoid
bone and the pterygoid process, and is attached to the neck of the mandibular
condylar process and to the capsule and articular disk of the temporomandibular
joint.
The medial pterygoid – is a thick, quadrilateral muscle and resembles the
masseter in form. It arises in the pterygoid fossa of the pterigoid process and
attaches to the medial surfase of the mandibular angle at the pterygoid tuberosity.
The Temporal, Masseter and Medial pterygoid rise the lower jaw against
the upper with great force. The superficial portion of the Masseter assists the
Lateral pterygoid in drawing the lower jaw.
All Chewer muscles are supplied by the third branch of the n.trigemins
(trigeminal nerve). Contracture of all chewer muscles and at least one of them
inevitably causes the immobility of the lower jaw. This is termed as trismus (lock
jaw) in stomatology.
There are many spaces, which are filled with fatty tissue. These spaces play
an important role in spreading inflametion processes and hematomas. These spaces
are limited by facies:
1. Temporal fascia (f. temporalis) covers the temporal muscle and arises
above from the temporal line. Below the temporal line it attaches to the zygomatic
arch and seperates into two layers: superficial layer and deep layer. The space
between the two layers is filled with fatty tissue. The temporal fascia closes the
cranial fossa temporalis in the osteo-fibrous receptacle that lodges the temporal
mascle with fatty tissue.
2. Masseteric f. F. coveres the masseter muscle and attaches to the
zygomatic arch above to the mandibula boder below and to the mandibula ramus
posterioly and anterioly
3. Posterioly and partly externally this fascia is connected with the parotid
fascia , which forms a capsule around the gland.
4. Buccopharyngeal fascia. It lies on the buccinator muscle and becomes
loose anterioly and blends with the fatty tissue of the cheek, fuses posterioly with
the pterygomandibular raphe and is continuous with the connective-tissue covering
of the pharingeal muscles.
Muscles of Facial Expression
The
muscles of facial expression are small, thin muscle bundles
grouped around the natural orifices (eyes, ears,nose and mouth). These muscles
take part in closing or widening the orifices, take part in speech, mastication and so
on.
The muscles of the face are in the subcutaneous tissue; most of them attach
to the skull bones and the skin or mucous membrane. By changing the shape of the
orifices and moving the skin with the formationof various folds, the muscles lend
the face various emotional expressions. All muscles of facial expression develop
from the 2nd pharyngeal arch and are supplied by its nerve, the 7th cranial nerve.
Muscles of the Scalp
Almost the whole skull cap is covered by a thin epicranius muscle which
has a wide tendinose part the epicranial aponeurosis (galea aponeurotica) and a
muscular part separating into three bellies: frontal, occipital, lateral belly seperates
into three auricle muscles.
Muscles of the Mouth, Lips, and Cheeks
Several muscles alter the shape of the mouth and lips. The shape of
the mouth and lips is controlled by a complex three-dimensional group of
muscllar slips:
elevators, retractors, and evetors of the upper lip;
 depressors, retractors, and evertors of the lower lip;
 a compound sphincter around the mouth;
 the buccinator in the cheek.
At rest lips are in gentle contact and the teeth are close together.
The muscles: m. Orbicularis oris,
dilator muscles, m. Mentalis, mm.
Levator labii superioris alaeque nasi, m. Buccinator, m. Depressor anguli oris, m.
Levator
anguli oris, mm. Zigomaticus major et minor, mm. Levator labii superioris
and inferioris, m. Depressor labii superioris, m. Depressor labii inferioris, m
Risorius.
Muscles Around the Orbital Opening
The function of the evelids is to protect the eye from injury and
excessive light. The eyelids also keep the cornea moist by spreading the tears.
The m. Orbital oculi closed the eye and wrinkles the forehead
vertically. The m. Orbicularis oculi consists of three parts;
 the lacrimal part;
 the palpebral part;
 the orbital part.
The m. Corrugator supercilii aries from the orbital part of the m. Orbicularis
oculi and nasal prominence and inserts into the skin of the eyebrow.
Muscles Around the Nose
The m.Procerus and m. Depressor septi are reletively unimportant to most
health care professionals. The main muscle of the nose, consists of transverse and
alar parts. The transverse part arises from the superior part of the canine ridge on
the anterior surface of the maxilla, superior to the incisor teeth. The alar
part arises from the maxilla superior to the transverse part and attaches to the
alar carilages of the nose.
All mimic muscles are supplied by facial nerve. When innervation of
mimic muscles is distored there appear a mask-like face.
Muscles of the Neck
The muscles of the neck may be arranged into groups corresponding
to the region in which they are situated:
1. Superficial region: 1.Platysma myoides
2.Sterno-cleido-mastoid
2. Medial muscles, or muscles of the hyoid bone
I. Suprahyoid region or m.located above the hyoid bone:
1
1.Digastric 2.Stylo-hyoid 3.Mylohyoid
4.Geniohyoid
II.Infrahyoid region, m. located below the hyoid bone:
1.Sternohyoid 2.Sternothyroid 3Thyrohyoid 4.Omohyoid
3. Deep muscles:
I.Lateral atteched to the ribsScalenus anterior. Scalenus medius Scalenus
posterior
II.Prevertebral muscles m.longus colli, m. longus capitis, m.rectus
capitis anterior et lateralis.
TOPOGRAPHY OF THE NECK
The neck is divided into four regions: posterior, lateral, the region of the
sternocleidomastoid muscle and the anterior region.
The posterior region (regio colli posterior) is behind the lateral
border of the trapezius muscle and is the nape or nucha.
The
lateral
region
(regio
colli
lateralis)
is
behind
the
sternocleidomastoid muscle and is bounded in front by the trapezius muscle.
The
sternocleidomastoid
region
(r.sternocleidomastoidea)
corresponds to the projection of this muscle.
The anterior region (regio colli anterior) is in front of the
sternocleidomastoid muscle and is bounded posterioly by this muscle, in front by
the midline of the neck, and above by the border of the mandible. A small area
behind the mandibular angle and in front of the mastoid process is called the fossa
retromandibularis. It lodges the posterior part of the parotid gland, nerves, and
vessels.
The anterior and lateral region are divided into a number of triangles
by the omohyoid muscle descending obliquely from front to back and crossing the
sternocleidomastoid muscle.
The posterior triangle of the neck has:
 an anterior boubdary, formed by the posterior border of the SCM ;
 a posterior boundary, formed by the anterior border of the trapezius;
 an inferior boundary, formed by the middle third of the clavicle between
the trapezius and SCM;
 its apex, where the SCM and trapezius meet on the superior nuchal line
of the occipital bone;
 a roof, formed by the investing leyer of deep cervical fascia;
 a floor, formed by muscles covered by the prevertebral layer of deep
cervical fascia.
The posterior triangle is subdivided into the omoclavicular
and
omo-trapesoid triangles.( trigonum omoclaviculare and omotrapesoideum)
The anterior tiangle of the neck has:
 an anterior boundary, formed by the median line of the neck;
 a posterior boundary, formed by the anterior of the SCM;
 a superior boundary, formed by the inferior border of the mandible;
 its apex, at the jugular notch in the manubrium;
 a roof, formed by subcutaneous tissue containing the platyzma
 a floor, formed by the pharynx, laryx, and thyroid gland.
The anterior triangle is subdivided into three triangles: trigonum
submandibulare, caroticum and trigonum omotracheale.
Triangular slits or spases form between the scalene muscles; they
transmit nerve and vessels of the upper limb.
1. Between the anterior and middle scalene muscles is spatium
interscalenum, bounded by the fist rib below (it transmits the subclavian artery
and the brachial plexus).
2. In front of the anterior scalene muscle is spatium antescalenum covered
in front by the sternothyroid and sternohyoid muscles (it transmits the subclavian
vein, the suprascapular artery, and the omohyoid muscle).
Fasciae of the Neck
Fascia is the collective term for connective tissue layers of the neck:
1. Superficial cervical fascia ( f. colli superficialis) is part of the common
superficial (subcutaneus) fascia of the body. It surrounds the platisma.
2. Superficial layer of the cervical fascia proper (lamina superficialis f.
colli propria) encloses the whole neck like a collar and covers suprahyoid and
infrahyoid group of muscles, the salivary glands, the vessels and the nerves.It is
surrounded the sternocleidomastoideus, and trapezius muscle. One part of this
fascia is attached above to the anterior part of the mandible and the other part is
attached to the posterior part of this bone. Spatium submandibulare is located
between this parts of the superficial layer. is continuous on the face with the
parotid and masseteric fasciae which cover the parotid gland and the masseter
muscle. In front on the midline, it fuses with the deep layer of the cervical fascia
proper to form the linea alba cervicalis ( 2-3 mm in width).
3. Deep layer of the cervical fascia proper(lamina profunda f. colli
propria) is manifest only in the middle part of the neck behind the
sternocleidomastoid muscle where it is stretched like a trapesium. This fascia is
attached below to the posterior border of the manubrium sterni and the clavicles,
while the superficial layer is attached to the anterior border of these bones, a
narrow space is left between these layers; this is spatium interaponeuroticum
suprasternale containing loose fatty tissue and the superficial veins of the neck,
the jugular venous arch (arcus venosus juguli), injury to which is fraught with
danger. Laterally this space communicates with recessus lateralis, a blind space
behind the inferior end of the SCM muscle spatium retrosternocleidomastoideum.
The deep layer, separating and again fusing, forms fascial sheaths for the
innfrahyoid muscles.
4. Endocervical fascia (f. endocervicalis) ( or pretracheal layer) consists of
two layers ( parietal and visceral). Visceral layer encloses the organs located in the
neck (larynx, trachea, thyroid gland, pharynx, oesophagus). Parietal layer forms a
sheath for the important vessels and
nerve the common carotid artery, jugular
vein and vagus nerve.
The space between the parietal and visceral layers of the endocervical fascia
lies in front of the viscera and is therefore called previsceral space (spatium
previscerale), that in front of the trachea is called pretrachel space (spatium
pretracheale). This spatium contains in addition to fatty tissue and lymph nodes,
the isthmus of the thyroid gland and blood vessels (arteria thyroidea ima) which
can be injured during tracheotomy.
5. F. prevertebral is a layer that lies between the vertebral column and
pharyngeal constrictors.
Lecture №6
Clinical Anatomy of “ weak places” of the Body
The abdominal cavity is the lower part of the trunk between the thorax and
pelvis. It has musculotendinous anteriolateral wall, and posterior wall which is
formed by bones, muscles and fasciae. The diaphragm forms the roof of the
abdominal cavity. Some abdominal organs – the spleen, liver, part of the kidneys,
and stomach – are protected by the abdominal cavity.
Constituent Layes of Abdominal Wall from outside on wards:
1. Skin, 2. Superficial Fascia, which consists of two layers in many regions
a) Superficial – fatty, b) Deep membranous. 3. Muscles in some regions covered
by fasciae. 4. F. abdominal propria which surrounded muscles of the abdominal. 5.
The deep layer of f. endoabdominalis covered abdominal cavity inside.
Muscles of the Anterolateral Abdomenal Wall
Trere are five muscles in the anterolateral abdominal wall: three flat
mucles and two vertical muscles.
The three flat muscles of the anterolateral abdomenal wall are the:
 external oblique; internal oblique; transverse abdominal.
The two vertical muscles of the anterior abdomenal wall are within
the rectus sheath: rectus abdominis; pyramidalis.
The aponeurouses of three lateral muscles form Linea alba (white line). It is
a fibro tendinous raphe situated in the median line in front of abdominal wall and
extends from xiphoid process to symphysis pubis. Above umbilical ring this line
wide and thin, but below it is narrow and thick. So, hernias of white line occurs
frequently above umbilical ring.
The aponeuroses of External, Internal oblique and Transversus abdominis
form
Rectus sheath ( Vagina m. recti abdominis). At different levels it is formed
in different ways. Upper umbilicus:
Anterior wall: 1. Aponeurosis of External oblique muscle of abdomen.
2.Anterior lamella of Internal oblique muscle of
abdomen.
Posterior wall: 1. Posterior lamella of aponeurosis of Intern. oblique
2. Aponeurosis of Transversus abdominis
3. Fascia Transversalis
Region below umbilicus
Anterior wall:
1. Aponeurosis of External oblique.
2. Aponeurosis of Internal oblique
3. Aponeurosis of Transversus abdominis
Posterior wall – deficient and Rectus abdominis lies directly on transversalis
fascia
Arcuate line – is the lower free concave margin of posterior wall of wall of
rectus sheath situated at the mid point of umbilicus and symphysis pubis. Below
this level the posterior wall of rectus sheath is deficient.
The linea alba contains the umbilical ring, a defect in the linea alba
through which the fetal umbilical evssels pass to and from the umbilical cord and
placenta.
Lumbul triangle is weak area of the back borded by the latissimus
dorsi, external oblique and iliac crest.
Inguinal canal situated in lower part of anterior abdominal wall about
half an inch above and parallel to medial half of inguinal ligament. Length of this
canal-4cm.
Contents:
In male – Spermatic cord; ilioinguinal nerve.
In Female – Round ligament of Uterus; Ilioinguinal nerve.
Walls of Inguinal canal:
1.Inguinal ligament – inferiorly
2.External oblique aponuerosis– anterioly
3.Internal oblique and transversus abdom. muscle – upper
4.Transversalis fascia – posteriorlly.
Superficial inguinal ring ( annulus ingvinalis superfis) – external
opening of the inguinal canal
1. Crus mediale – group of fibers of the external oblique aponuerosis
ascending obliquely medial to the superficial inguinal ring
2. Lateral crus – group of fibers of the external oblique aponeurosis
ascending lateral to the superficial inguinal ring
3. Reflected ligament ( lig.reflexum) – Curved band of fibers passing
upward from the medial attechment of the inguinal ligament and forming the
medial lining of the superficial inguinal ring.
4. Intercrural fibers (f. intercrurales) – curved fibers between the medial and
lateral crura.
Deep inguinal ring ( annulus inguinalis profundus) – inner inguinal ring at
the transition of the transversalis fascia into the internal spermatic fascia.
Abdominal Hernias
The anterolateral abdominal wall may be the site of hernias. Most
hernias occur in the inguinal, umbilical, and epigastric regions. Umbilical hernias
are common in newborns because the anterior abdominal wall is relatively weak
in the umbilical ring, especially in low-birth-weight infants. Umbilical hernias are
usually small and result from increased intra-abdominal pressure in the presence of
weakness and incomplete closure of the anterior abdominal wall after ligation of
the umbilical cord at birth. Herniation occurs through the umbilical ring – the
oppening in the linea alba. Acquired umbilical hernias occur most commonly in
women and obese people. An epigastric hernia – a hernia in the epigastric region
through the linea alba – occurs in the midline between the xiphoid process and the
umbilicus. Epigastric hernias tend to occur in people older than 40 years and are
usually associated with obesity. Inguinal hernia may form in the region of
superficial inguinal ring or deep inguinal ring.
Lecture №7
The Types of Muscles of the Extremities and their Functions. Surface
Forms of Muscles of Extremities and their Clinical Role
Plan of the Lecture:
1. Anterior Thoracoappendicular Muscles of the Upper Limb.
2. Muscles of the Arm, of the Forearm, and of the Hand.
The upper limb (extremity) is characterized by its mobility and ability
to grasp and manipulate. These characteristics are especially marked in the hand
(manus) when performing manual activities such as buttoning a shirt. Because the
upper limb is not usually involved in weightbearing, its stability has been
sacrificed to gain mobility. The digits (fingers including the thumb) are the most
mobile, but other parts are still more mobile than comparable parts of the lower
limb.
The upper limb consists of four segments:
 pectoral girdle – the bony ring, incomplete posteriorly, formed by the
scapulae and clavicles, which is completed anteriorly by the manubrium of the
sternum;
 arm –the part between the elbow containing the humerus, which connects
the shoulder and the elbow;
 forearm – the part between the elbow and wrist containing the ulna and
radius, which connect the elbow and wrist;
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 hand – the part of the upper limb distal to the forearm containing the
carpus, metacarpus, and phalanges, which is composed of the wrist, palm, dorsum
of hand, and finges including the thumb.
Anterior Thoracoappendicular Muscles of the Upper Limb
Four anterior thoracoappendicular (pectoral) muscles move the
pectoral girdle: pectoral major, pectoral minor, subclavius, and serratus anterior.
The pectoral major, large and fan shaped, covers the superior part of
the thorax. The latter head is much larder, and its lateral border is responsible for
the muscular mass that forms most of the anterior wall of the axilla, with its
inferior border fopming the anterior axillary fold. The pectoralis major and
adjacent deltoid form the narrow deltopectoral groove, in which the cephalic vein
runs. The pectoralis major is a powerful adductor of the arm and a medial rotatot of
the humerus.
The pectoral minor lies in the anterior wall of the axilla, where it is
lardely covered by the much larder pectoralis major. The pectoralis minor
stabilizes the scapula and is used when stretching the arm forward to touch an
object that is just out of reach. The pectoral minor is a useful anatomical and
surgical landmark for structures in the axilla.
The subclavius lies almost horizontally when the arm is in the
anatomical position. This muscle is located inferior to the clavicle and affords
some protection to the suclavian artery when the clavicle fractures.
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The serratus anterior overlies the lateral part of the thorax and
forms the medial wall of the axilla.
Scapulohumeral Muscles.
The six scapulohumeral muscles (deltoid, teres major, teres minor,
supraspinatus, and subscapularis) are relatively shot muscles that pass from the
scapula to the humerus and act on the glenohumeral (shoulder) joint.
Axilla.
The axilla (armpit) is the pyramidal space inferior to the
scapulohumeral joint and superior to the axially fascia at the junction of the arm
and thorax. The axilla has an apex, a base, and four walls, three of which are
muscular:
 anterior wall of axilla is formed by the pectoralis major and pectoralis
minor and the pectoral and clavicopectoral fascia associated with them;
 posterior wall of axilla is formed by the scapula and subscapularis on its
anterior surface and inferiorly by the teres major and latissimus dorsi;
 medial wall of axilla is formed by the thoracic wall and the overlying
serratus anterior;
 lateral wall of axilla is a narrow bony wall formed by the intertubercular
groove in the humerus.
The axilla contains axillary blood vessels (axillary artery and its
branches, axillary vein), lymphatic vessels, and several groups axillary lymph
nodes. The axilla also contains large nerves of the brachial plexus.
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Muscles of the Arm, the of Forearm, and of the Hand
The arm
extends from the eblow. Two types of movement occur
between the arm abd forearm at the elbow joint: flexion-extension and
pronation0supination. The muscles perfoming these monements are clearly divided
into anterior and posterior groups.
Of the four arm (brachial) muscles, three flexors (biceps brachii,
brachialis, coracobrachialis) are in the anterior compartments and one extensor
(triceps brachii) is in the posterior compartment. The anconeus muscle, at the
posterior aspect of the elbow, is partly blended with – and is essentially a distally
placed continuation of – the triceps.
Cubital fossa.
The cubital fossa is the triangular hollow area on the anterior aspect of
the elbow. The boundaries of the cubital fossa are:
 superiorly – an imaginary line connecting the medial and lateral
epicondyles;
 medially – the pronator teres;
 laterally – the brachioradialis.
The floor of the cubital fossa is formed by the brachialis and supinator
muscles of the arm and forearm, respectively. The roof of the cubital fossa is
formed by deep fascia – reiforced by the bicipital aponeurosis – subcutanel tissue,
and skin.
The muscles of the forearm act on the joints of the elbow, wrist, and digits.
In the proximal part of the forearm, the muscles form fleshy masses extending
inferiorly from the medial and lateral epicondyles of the humerus. The tendons of
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these muscles pass through the distal part of the forearm and cotinue into the
wrist, hand, and digits.
Flexor-Pronator Muscles of the Forearm are in the anterior
compartment of the forearm and are separated from the extensor muscles of the
forearm by the radius and ulna and the interosseus membrane that connects them.
The flexor muscles are arranged in four layers and are divided into
two groups, superficial and deep.
 a superficial group of five muscles (pronator teres, flexor carpi radialis,
palmaris longus, flexor carpi ulnaris, and flexor digitorum superficialis);
 a deep group of three muscles (flexor digitorum profundus, flexor
pollicis longus, and pronator quadratus).
Extensor Muscles of the Forearm are in the posterior (extensor-supinator)
compartment of the forearm. These muscles can be organized into three
functional groups:
 muscles that extend and abduct the hand at the wrist joint (extensor carpi
radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris);
 muscles that extend and medial four digits (extensor digitorum, extensor
indicis, and extensor digiti minimi);
 muscles that extend or abduct the 1st digit, or thumb (abductor pollicis
longus, extensor pollicis brevis, and extensor pollicis longus.
Muscles of the Hand
The intrinsic muscles of the hand are in four compartments:
 thenar muscles in the thenar compartment: abductop pollicis brevis,
flexor pollicis brevis, and opponens pollicis;
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 adductor pollicis in the adductor compartment;
 hypothenar muscles in the hypothenar compartment: abductor digiti
minimi, flexor digiti minimi, and opponens digiti minimi;
 short muscles of the hand: the lumbricals are in the central
compartment and interossei are between the metacarpals.
Lecture №8
Biomechanics of Human Locomotor System
Plan of the Lecture:
1. Organization of Thigh Muscles.
2. Gluteal Region.
1. Popliteal Fossa.
2. Muscles of the Leg and of the Foot.
Organization of Thigh Muscles
The thigh muscles are organized into
three compartments by
intermuscular septa that pass between the muscles from the fascia lata to the femur.
The compartments are anterior, medial, and posterior,so named on the basis of
their location, and actions.
Anterior Thigh Muscles.
The anterior thigh muscles – the flexors of the hip and extensors of
the knee – are in the anterior compartments of the thigh. For attachments,main
actions of these muscles. The anterior thigh muscles are:
 pectineus;
 iliopsoas;
 tensor of fascia lata;
 sartorius;
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 quadriceps femoris.
The pectineus is a flat quadrangular muscle located in the anterior part of
the superomedial aspect of the thigh. The pectineus adducts and flexes the thigh
and assists in medial rotation of the thigh.
The iliopsoas is the chief flexor of the thigh. Its board lateral part , the
iliacus, and its long medial part, the psoas major , arise from the iliac fossa and
lumbal vertebrae, respectively.
The tensor of fascia lata is a fusiform muscle approximately 15 cm long
that is enclosed between two layers of fascia lata. The tensor of fascia lata is a
flexor of the thigh. It also tenses the fascia lata and iliotibial tract.
The sartorius is a long muscle that passes obliquely across the
superoanterior part of the thigh. The sartorius, the longest muscle in the body, acts
across two joints : it flexes the hip joint and participates in flexion of the knee.
The quadriceps femoris (L. Four-haeded femoral muscle) forms the main
bulk of the anterior thigh muscles and collectively constitutes the largest and one
of the most powerful muscles in the body. It covers almost all the anterior aspect
and sides of the femur. The quadriceps cosists of four parts:
 rectus femoris;
 vastus lateralis;
 vastus intermedius;
 vastus medialis.
The quadriceps is an important muscle during climbing, running, jamping,
rising from the siting position, and walking up and down stairs.The tendons of the
four parts of the quadriceps unite in the distal portion of the thigh to form a single,
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strong, broad quadriceps tendon. This tendon is traditionally discribed as
attaching to the base of the patella, a large sesamoid bone in the tendon, which in
turn is attached through the patellar ligament to the tibial tuberosity.
Vastus lateralis lies on the lateral side of the thigh; vastus medialis
covers the medial side of the thigh; vastus intermedius lies deep to the rectus
femoris, between the vastus medialis and vastus lateralis.
Medial Thigh Muscles.
The medial thigh muscles – the adductor group – are in the medial
compartment of the thigh. It consists of:
 adductor longus;
 adductor brevis;
 adductor magnus;
 gracilis;
 obturator externus.
Collectivelly, these muscles are the adductors of the thigh; however, the
actions of some of these muscles are more complex.
Femoral Triangle – a junctional region between the trunk and lower limb is a
triangular fascial space in superoanterior third of the thigh. It appears as a
triangular depression inferior to the inguinal ligament when the thigh is flexed,
abducted, and laterally rotated. The femoral triangle is bounded:
- Superiorly by the inguinal ligament;
 Medially by the adductor longus;
 Laterally by the sartorius.
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The femoral canal – the smallest of the three femoral sheath compartments –
is the short (1.25 cm), conical medial compartment of the femoral sheath that lies
between the medial edge of the femoral sheath and the femoral sheath and the
femoral vein. The base of the femoral canal ( its abdominal end) is directed
superiorly and , although oval shaped, is called the femoral ring.
The femoral ring – the small proximal opening of the femoral canal ( 1cm
wide) – is closed by extraperitoneal fatty tissue that forms the femoral septum.
The abdominal surface of this septum is covered by parietal peritoneum. The
femoral septum is pierced by lymphatic vessels connecting the inguinal and
external iliac lymph nodes. The boundaries of the femoral ring are:
 Laterally, the partition between the femoral canal and femoral vein;
 Posteriorlly, the superior ramus of the pubis covered by the pectineus and
its fascia;
 Medially, the lacunar ligament;
 Anteriorlly, the medial part of the inguinal ligament.
The adductor canal (Hunter,s canal) – 15 cm long, is a the thigh running
from the apex of the femoral triangle to the adductor hiatus in the tendon of the
adductor magnus. The contents of the adductor canal are the:
 femoral artery and vein;
 saphenous nerve;
 nerve to vastus medialis;
The adductor canal is bounded:
 anteriorly and laterally by the vastus medialis;
 posteriorly by the adductors longus and magnus;
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 medially by the sartorius.
Gluteal Region
The gluteus region lies posterior to the pelvis between the level of the
iliac crests and the inferior borders of the gluteus maximus muscles.
Gluteus Ligaments.
The part of the bony pelvis – hip bones, sacrum, and coccyx – are
bound together by dense ligaments. The sacrotuberous and sacrospinous
ligaments convert the sciatic notches in the hip bones into the greater and lesser
sciatic foramina. If is helful to think of the greater sciatic foramen as the “door”
through which all lower limb arteries and nerves leave the pelvis and enter the
gluteal region.
Posterior Thigh Muscles.
The three muscles in the posterior aspect of the thigh are the
hamstring:
 semitendinosus;
 semimembranosus;
 biceps femoris.
The hamstrings are extensors of the thigh and flexors of the leg.
Popliteal Fossa
The popliteal fossa is the diamond-shaped depression of the posterior
aspect of the knee. The fossa is bounded superiorly by the hamstring and inferiorly
by the two neads of the gastrocnemius and the plantaris. All important vessels and
nerves from the thigh to the leg pass through this fossa. The popliteal fossa is
formed:
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 superolayerally by the bicips femoris (superolateral border);
 superomedially by the semimembranosus, lateral to which is the
semitendinosus (superomedial border);
 inferolaterally and inferomedially by the lateral and medial heads of the
gastrocnemius (inferolateral and inferomedial borders).
Muscles of the Leg and of the Foot
The leg is divided into three fascial compartmenrs – anterior, lateral,
and posterior – by the anterior and posterior intermuscular septa and the
interosseous membrane. The anterior septum separates the anterior and lateral leg
muscles, and the posterior septum separates the lateral and posterior muscles; thus,
each group has its own compartment.
Anterior Compartment of the Leg.
The anterior compartment is bounded anteriorly by crural fascia and
skin.
The four muscles in the anterior compartment are the:
 tibialis anterior;
 extensor digitorum longus;
 extensor hallucis longus;
 fibularis tertius.
Lateral Compartment of the Leg.
The lateral compartment is bounded by the lateral surface of the fibula, the
anterior intermuscular septa, and the crural fascia.
The lateral compartment contains the fibularis longus and brevis
muscles.
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Posterior Compartment of the Leg.
The posterior compartment is the largest of the free leg compartments. The
calf muscles in the posterior compartment are divided into superficial and deep
groups by the trasverse intermuscular septum.
The superficial group of muscles – gastrocnemius, soleus, and plantaris –
forms a powerful mass in the calf of the leg that plantar flexes the foot. Together,
two-headed gastocnemius and soleus form the three-headed triceps surae. This
large muscle has a common tendon - the calcaneal tendon (Achilles tendon) –
which attaches to the calcaneus.
Deep Muscles Group in the Posterior Compartment.
Four muscles comprise the deep group in the posterior compartment of the
leg:
 popliteus;
 flexor digitorum longus;
 flexor hallucis longus;
 tibialis posterior.
The popliteus acts on the knee joint, whereas the other muscles act on the
ancle and foot joints.
Muscles of the Foot.
The four layers in the sole of the foot help maintain the arches of the
foot and enable one to stand on uneven ground.
The 1st layer of plantar muscles consists of:
 abductor hallucis;
 flexor digitorum brevis;
 abductor digiti minimi
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The 2nd layer of plantar muscles consists of:
 quadratus plantae;
 tendons of flexor hallucis longus and flexor digitorum longus;
 lumbricals.
The 3rd layer of plantar muscles consists of:
 flexor hallucis brevis;
 adductor hallucis;
 flexor digiti minimi brevis.
The 4th layer of plantar muscles consists of:
 three plantar interossei;
 four dorsal interossei.
The lateral plantar artery and nerve course laterally between the muscles of
the 1st and 2nd layers of plantar muscles. Their deep branches course medially
between the muscles of the 3rd and 4th layers.
Lecture № 1
Functional Anatomy of the Skull.
The plan of lecture:
6. The Skeleton of the Head.
7. Development of the Skull.
8. Connection of the Skull s bone.
9. Age features of the Skull.
10.Anterior, Lateral, Posterir, Superoir Aspects of the Skull. External
and Internal Aspects of the Cranial Base.
The Skeleton of the Head
The skull ( or cranium in Latin) is the skeleton of the head.It consists of two
parts, the neurocranium and fasial skeleton. The neurocranium (“brain box” or
cranial vault) provides a case for the brain and cranial meninges. The facial
skeleton consists of the bones surrounding the mouth and nose and contributing to
the orbits (eye sockets, orbital cavites).
The neurocranium in adults is formed by a series of eight bones:

a frontal bone;

two parietal bones;

two temporal bones;

an occipital bone;

a sphenoid bone;

an ethmoid bone.
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The facial skeleton consists of 14 bones:

lacrimal bones (2);

nasal bones (2);

maxillae (2);

zygomatic bones (2);

palatine bones (2);

inferior nasal conchae (2);

mandible (1);

vomer (1).
The cranium has a domelike roof – the calvaria (skullcap) – and a floor or
cranial base (basicranium) consisting of the ethmoid bone and parts of the occipital
and temporal bones.
Development of the Skull
The bones forming the calvaria and some parts of the cranial base
develop by intramembranous ossification. These bones is called primary bones.
Whereas most parts of the cranial base develop by endochondral ossification. Thus
bones are called secondary bones.
The structure of the calvaria bones differens from the other bones of the
skull.
Most of these bones are largely flat, curved, and united by fibrous
interlocking sutures. These bones are composed of two layers of compact tissue
enclosing between them a variable quantity of cancellous tissue.In the cranial
bones
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the outer layer is thick and tough, the inner one thinner, denser and more
brittle. The intervening cancellous tissue is called diploe(layer of spongy bone)
Large venous canals are situated in the diploe.
In the anatomical position, the skull is oriented so that the inferior margin of
the orbit and the superior margin of the external acoustic meatus of bouth sides lie
in the same horizontal plane. This standard craniometric reference is the
orbitomeatal plane.
The other important feature of the skull is the presence of pneumetic
bones. They are the bones with air-containing cells or sinuses. They are needed to
make the skull bone lighter and they give timbre to the voice. All sinuses of the
pneumatic bone open in the meatus of nasal cavity. S.sphenoidal and posterior
cells of ethmoid open in superior nasal meatus, frontal, maxillary sinuses and
anterior and medial cells of the ethmoid open in the middle nasal meatus.
Connections of the bones of the skull
The bones of the skull, with the exeption of the Mandible are connected to
each other by means of Sutures. They are closely adapted to each other.
There are 4 S.in the skull, they are: sagittal, coronal, lambdoid and
sguamous.
1The Sagital Suture is formed by the junction of the two parietal
bones.
2.
The Coronal Suture extends transversely across the vertex of the
skull and connects the frontal with the parietal bones.
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3.
The Lambdoid S. is so called from its resemblance to the Greek
latter, and it
4.
connects the occipital with the parietal bones
The Squmous S is the joints between squamous part of temporal bone
and parietal bone.
There is only one movable articulation in the head. It is
Temporomandibular Joint (TMJ).
The TMJ is a modified hinge type of joint. The articular surface
involved are the condyle of the mandible, the articular tubercle of the temporal
bone, and the mandibular fosse. The articular capsule of the TMJ is loose. The
fibrous capsule attaches to the margins of the articular area on the temporal bone
and around the neck of the mandible. The joint has two synovial membranes:
 the superior synovial membrane lines the fibrous capsule superior to the
articular disc;
 the inferior synovial membrane lines the capsule inferior to the disk.
The articular disk divides the joint into two separate compartments. The
thick part of the articular capsule forms the intrinsic lateral ligament (ligamentum
temporomandibularis), which strengthens the TMJ laterally and, with the
postglenoid tubercle, acts to prevent posterior dislocation of the joint.
Two extrinsic ligaments and the lateral ligament connect the
mandible to the cranium. The stylomandibular ligament – runs from the styloid
process to the angle of the mandible. The sphenomandibular ligament runs from
the spine of the sphenoid to the lingula of the mandible.
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The movements of the mandible at the TMJ are as follows: Depression
(open mouth), Elevation (closed mouth), Protrusion (protraction of chin).
The next peculiarity of the skull structures is the presence of the
strongest zones (areas) of the skull. These zones counteract the mechanical
influence during the process mastication in normal conditions and in fractures and
injuries.
They are called contrforces in the facial part of the skull.
They are called arches in the calvaria.
They are called trabecula in the bases of the skull.
They are all connected with each other.
Dr. Le Fort, a Paris surgeon classified the common variants of
fractures of the maxilla. There are 3 types of fracture, they are:
A Le Fort I is located just superior to the alveolar process, crossing
the bony nasal septum and the pterigoid plates of the sphenoid.
A Le Fort II passes from the maxillary sinuses, through the
infraorbital foramina, lacrimals or ethmoid to the bridge of the nose.
A Le Fort III passes through the superior orbital fissures, the ethmoid
and nasal bones and extends laterally through the greater wings of the sphenoid
bone.
Fractures of the mandible
There are 4 types of mandible s fractures, they are: Fractures of the coronoid
process; fr. of the neck of the mandible; fr.of the angle of the mandible; fr. of the
body of the mandible.
Age features of the Skull
At birth, the bones of the calvaria are smooth and unilaminar; no diploe is
present. The frontal and parietal eminences are especially prominent. The skull of a
newborn infant is disproportionately large compared with other parts of the
skeleton; The
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large size of the newborn, s calvaria results from precocious growth and
development of the brain. The smallness of the face results from the absence of
erupted teeth, and the small size of the nasal cavities.
The halves of the frontal bone are separated by a frontal suture but the
greater part of it usually disappeared about the 15 or 16 year.The maxillae and
mandibles are separated by an intermaxillary suture and mandibular symphysis,
respectively.
At an early period of life a thin plate of cartilage exists between the
basilar surface of the body of the occipital bone and the posterior surface of the
body of the sphenoid. In the adult they become fused and the basilar suture is
formed.
The bones of the calvaria of a newborn infant are separated by areas of
fibrous tissue membrane – the fontaneless – which represent parts of unossified
bones. There are six fontanelles : two are in the median plane – anterior and
posterior – and two pairs are on each side – the anterolateral or sphenoidal fon. and
the posterolateral or mastoid fon.
The anterior fon. is located at the junction of the sagital, coronal, and
frontal sutures, the future site of the bregma. By 18 months of age, the surrounding
bones have fused and the anterior fon. is no longer clinically palpable. The posteror
fon. is triangular and bounded by the parietal bones anteriorly and occipital bone
posteriorly. It is located at the junction of the lambda. The posterior fon. begins to
close during the first few months after birth, and by the end of the 1 st year it is
small and no longer clinically palpable.
The bones of the fetal skull are very resilient. The increase in the size
of the calvaria is greatest during the first 2 years, the period of most repid brain
development. A person, s calvaria normally increases in capacity until 15 or 16
years of age.
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External Aspect of the skull has three thopografic features, three
fossae: temporal fossa, infratemporal fossa and pterygopalatine fossa.
Temporal fossa is a bony fossa located on the lateral aspect of the
skull between the temporal line and the zygomatic arch.
Contains: 1. Temporal muscle
2. Deep temporal nerve and vessels.
Infratemporal fossa – bony space situated below the middle cranial
fossa of the skull, behind body of maxilla and lateral to lateral pterygoid plate. It
contains the pterygoid muscles, the pterygoid plexus and the ramus of the
mandibular nerve.
Pterygopalatine fossa – a small bony space situated deep to
pterygomaxillary fissure. This fossa communication with :
1.Orbit through inferior obital fissure
5.
Middle cranial fossa – through f. rotundum
6.
Oral cavity through canalis palatinus major
7.
Nasal cavity through f. sphenopalatinum
8.
F.Lacerum through pterygoid canal
Anterior, Lateral, Posterir, Superoir, External and Internal Aspects of
the Skull
Anterior Aspect of the skull.
Features of anterior aspect of the skull are the frontal and zygomatic
bones, orbits, nasal region, maxillae, and mandible.
The frontal bone- specifically its squamous part – forms the skeleton of
the forehead, articulating inferiorly with the nasal and zygomatic bones. The
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supraorbital margin, the angular boundary between the squamous and orbital
parts, has a supraorbital notch or a foramen in some skulls for passage of the
supraorbital nerve and vessels. Just superior to the supraorbital margin is a ridge –
the superciliare arch – that extends laterally on each side from the glabella. The
prominence of this ridge, deep to the eyebrows, is generally greater in males.
Within the orbits are the superoir and inferior orbital fissures and optic canals.
The maxillae form the upper jaw; their alveolar processes include the
sockets (alveoli) and constitute the supporting bone for the maxillare teeth. The
maxillae
have a broad connection with the zygomatic bones laterally and have an
infraorbital foramen inferior to each orbit for the infraorbital nerve and vessels.
The mandible consists of a horizontal part, the body, and a vertical
part, the the ramus. The mandible is a U-shaped bone with alveolar processes that
hous the mandibular teeth. Inferior to the second premolar teeth are the mental
foramina for the mental nerve and vessels. The mental protuberanse – forming the
prominence of the chin – is a triangular elevation of bone inferior to the
mandibular symphysis, the region there the halves of the fetal mandible fuse.
Lateral Aspect of the Skull.
The lateral aspect of the skull is formed by cranial and facial bones.
The main features of the cranial part include the temporal fossa, the opening of the
external acoustic meatus, and the mastoid region of the temporal bone. The main
features of
the facial part include the infratemporal fossa, zygomatic arch, and lateral
aspects of the maxilla and mandible. The temporal fossa is bounded superiorly
and posteriorly by the temporal lines, anteriorly by the frontal and zygomatic
bones, and inferiorly by the zygomatic arch.
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The external acostic meatus opening is the entrance to the external
acoustic meatus, which leads to the tympanic membrane. The mastoid proces of
the temporal bone is posteroinferior to the opening of the external acoustic meatus.
Anteromedial to the mastoid process is the slender styloid process.
Posterior Aspect of the Skull.
The posterior aspect of the skull, or occiput, is typically ovoid or
round in outline. It is formed by the occipital bone, parts of the parietal bones,
and mastoid parts of the temporal bones. The external occipital protuberance is
usually an easily
palpable elevation in the median plane. The external occipital crest descends
from the external occipital protuberance toward the foramen magnum – the large
opening
in the basal part of the occipital bone. The superior nuchal line, marking the
superior limit of the neck.In the center of the occiput, the lambda indicates the
junction of the sagittal and lambdoid sutures.
Superior Aspect of the Skull.
The superior aspect of the skull, usually somewhat oval in form,
broadens posterolaterally at the parietal eminences. The coronal suture separates
the parietal bones, and the lambdoid suture separates the parietal and temporal
bones from the occipital bone.The bregma is the landmark formed by the
intersection of the sagittal and coronal sutures. The vertex – the most superoir
point of the skull – is near the midpoint of the sagittal suture.
The inferior region or base of the skull presents two surfaces an
external or basilar and internal or cerebra.
External Aspect of the Cranial Base.
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The external surface of the cranial base shows the alveolar arch of the
maxillae, the palatine processes of the maxillae, and the palatine, sphenoid, vomer,
tenporal, and occipital bones.
Wedged between the frontal, temporal, and occipital bones is the
sphenoid bone, consists of the body, greater wings, lesser wings, and pterygoid
process. Depression in the temroral bone – the mandibular fossae – accommodate
the condyles of the mandible when the mouth is closed.
The cranial base is formed posteriorly by the occipital bone, which
articulates with the sphenoid bone anteriorly. The large opening between the
occipital bone and the petrous part of the temporal bone is the jugular foramen,
from which the internal jugular vein and several cranial nerves emerge from the
skull. Superolateral to the
jugular foramen is the internal acoustic meatus.The entrance to the carotid
canal for the internal carotid artery is just anterior to the jugular foramen. The
mastoid process is ridged because it is designed for muscle attachment. The
stylomastoid foramen, transmitting the facial nerve and stylomastiod artery, lies
posterior to the base of the styloid process.
Internal Aspect of the Cranial Base.
The internal surface of the cranial base has three large, depressions
that lie at different levels – the anterior, middle, and posterior cranial fossae –
which form the bowl-shaped floor of the cranial cavity.
Anterior Cranial Fossa. The inferior and anterior parts of the frontal
lobes of the brain occupy the anterior cranial fossae, the shallowest of the three
fossae. The anterior cranial fossa is formed by the frontal bone anteriorly, the
ethmoid bone in
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the middle, and the body and lesser wings of the sphenoid posteriorly. The
crista galli ( cock , s comb) is a median ridge of ethmoid bone. The foramen
caecum is anterially to the cock , s comb.
Middle Cranial Fossa. The middle cranial fossa is butterfly-shaped,
composed of large, deep depressions on each side of the much smaller sella turcica
centrally on the body of the sphenoid bone. The boundary between the middle and
posterior cranial fossae is the petrous crests of the temporal bones laterally
and a flat plate of bone, the dorsum sellae of the sphenoid, medially.
The sella turcica ( Turkish saddle)– is composed of three parts:

tuberculum sellae;

hypophyseal fossa;

dorsum sellae (“back of the saddle”).
In the middle cranial fossa on each side of the base of the body of the
sphenoid bone is a crescent of four foramina:

the superor orbital fissure is between the greater and lesser
wings. This fissure transmits the ophtalmic veins and nerves entering the orbit;

the foramen rotundum, it transmits the maxillary nerve;

the foramen ovale, it transmits the mandibular nerve;

the foramen spinosum, it transmits the middle meningeal vessels
and the meningeal branch of the mandibular nerve.
The foramen lacerum – not part of the crescent of foramina – is a ragged
foramen that lies posterolateral to the hypophysial fossa; it is an atrifact of a dried
skull.
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Posterior Cranial Fossa.
The posterior cranial fossa lodges the cerebellum, pons, and medulla
oblongata. The posterior cranial fossa is formed largely by the occipital bone, but
the dorsum sellae of the sphenoid marks its anterior boundary centrally
and the petrous and mastoid parts of the temporal bones contribute its
anterolateral “walls". From the dorsum sellae, the clivus is a marked incline in the
center of the anterior part of the posterior cranial fossa leading to the foramen
magnum.