Download Facial Bones

The Skeletal
System
Fun Facts
• A giraffe has the same # of bones in the neck as
humans do
• Bones are 14% of your body weight
• Bone is 5x as strong as steel
• Most women and girls have smaller and lighter
skeletons than men and boys
• The female pelvis is wider than males
• Male’s growth plates harden at 18-21 years of
age
• Female’s growth plates harden at 16-18 years of
age
How many bones does an adult
body have?
206
How many bones are babies born
with?
350
Largest bone?
Femur: thigh bone
Shortest Bone?
Stirrup: located in the ear
Functions of the Skeletal system
1.
2.
3.
4.
5.
Support
Protection
Movement
Mineral storage
Hematopoiesis (blood cell formation)
What’s in a bone?
• Bones, Muscles, and Joints
Classification of Bones
Bones are identified by:
1. Shape
A. Long bones
B. Short bones
C. Flat bones
D. Irregular bones
2. Internal tissues
A. Compact
B. Spongy
3. Bone markings
Osteogenesis (Bone Formation)
Ossification - the process of replacing other
tissues with bone
• The growth of the skeleton determines the
size and proportions of your body
• The bony skeleton begins to form about 6
weeks after fertilization
• Bone growth continues through
adolescence, and portions of the skeleton
do not stop growing until approx. the age
of 25
Shape: Long Bones
• Are typically longer than they are wide
• As a rule they have a shaft with heads
at both ends
• Mostly compact bone
• All of the limbs (femur, tibia,
humerus), except the wrist and ankle
bones.
Shape: Long Bones
Diaphysis (long part):
– Covered by periosteum
– Sharpey’s Fibers secure the
periosteum to the underlying
bone
Epiphysis (ends):
– Articulate with other bones
– Covered by Articular cartilage
Metaphysis:
– Location where diaphysis and
epiphysis meet
Shape: Flat Bones
• Are thin, flattened and
usually curved
• Have two thin layers of
compact bone sandwiching
a layer of spongy bone
between them
• Found in the skull,
sternum, ribs, and scapula
Shape: Irregular Bones
• Have complex shapes
• Examples: Vertebrae, Mandible, Sacrum,
Pelvis
Shape: Short Bones
• Are small and thick
• Cube-shaped and contain mostly spongy
bone
• Examples: Carpals, Tarsals,
Calcaneus
Shape: Sesamoid (ses’ah-moyd)
Bones
Special type of short bone
- Form within tendons
- Best known example is the patella
- Develop inside tendons near joints of
knees, hands, and feet
Check Point
1. Approximately how many bones are there in the
human body?
2. What is hematopoiesis?
3. What are the five functions of the bones?
4. What is the difference between compact bone and
spongy bone?
5. Name the parts of a long bone.
BONE MARKINGS
(Surface Features)
• Each bone in the body has characteristic
external and internal features.
• Every bump, groove, and hole has a
name on your bones.
• Detailed examination can yield an
abundance of anatomical information.
Bone Markings
• Two types of bone markings:
– Projections (aka processes) that grow out
from the bone
– Depressions (cavities) that indent the bone
The Axial Skeleton
• Includes 80 bones
• 40% of the bones in the
human body
Axial Skeleton
• Three Regions:
1. Skull (8 cranial & 14 facial)
** bones associated with skull (6 auditory
ossicles and hyoid)
2. Vertebral column (24 vertebrae, the sacrum
& coccyx)
3. Thoracic cage (sternum & 24 ribs)
The Skull
• The bones of the skull protect the brain and
guard the entrances to the digestive & respiratory
systems
• The skull (22 bones), the body’s most complex
bony structure, is formed by the cranium (8
bones) and facial bones (14 bones)
• 6 auditory ossicles (tiny bones) are situated
within the temporal bones of the cranium
(smallest bones in the body that are contained in
the middle ear space; hammer, anvil, stirrup)
• Hyoid bone (connected to the inferior surfaces of
the temporal bones)
The Skull
• Cranium – protects the brain and is the site of
attachment for head and neck muscles
• Facial bones
– Supply the framework of the face, the sense organs,
and the teeth
– Provide openings for the passage of air and food
– Anchor the facial muscles of expression
Anatomy of the Cranium
Eight cranial bones:
1.
2.
3.
4.
5.
6.
•
•
2 parietal
2 temporal
Frontal
Occipital
Sphenoid
Ethmoid
The cranial bones enclose the cranial cavity, a
fluid-filled chamber that cushions and supports
the brain
Cranial bones are thin and remarkably strong
for their weight
Skull – Anterior View
Figure 7.2a
Frontal Bone
• Forms the anterior portion
of the cranium & the roof
of the orbits (eye sockets)
Parietal Bones
• Forms most of the superior and lateral aspects of
the skull
Figure 7.3a
Parietal Bones & Major Associated Sutures
• Four sutures mark the articulations of the
parietal bones
1. Coronal suture – articulation between parietal bones
and frontal bone anteriorly
2. Sagittal suture – where right and left
parietal bones meet superiorly
Parietal Bones & Major Associated Sutures
3. Lambdoid suture – where parietal bones
meet the occipital bone (posterior)
4. Squamosal or
squamous suture –
where parietal and
temporal bones meet
Occipital Bone
• Located at the back and lower part of the
cranium
Temporal Bones
Form part of both
the lateral walls of
the cranium
Figure 7.5
Sphenoid Bone
• Butterfly-shaped bone that forms part of the
floor of the cranium, unites the cranial and
facial bones, and acts as a cross brace that
strengthens the sides of the skull
• Forms the central wedge that articulates
with all other cranial bones
Ethmoid Bone
• Most deep of the skull bones; lies between
the sphenoid and nasal bones
Figure 7.7
Facial Bones
• Fourteen bones of which only the
mandible and vomer are unpaired
• The paired bones are the maxillae,
zygomatics, nasals, lacrimals, palatines,
and inferior conchae
Mandible
• The mandible
(lower jawbone) is
the strongest bone
of the face
Figure 7.8a
Maxillary Bones
• Medially fused bones that make up the
upper jaw and the central portion of the
facial skeleton (largest facial bones)
Figure 7.8b
Zygomatic Bones
• Irregularly shaped bones (cheekbones)
that form the prominences of the cheeks
and the inferolateral margins of the orbits
Other Facial Bones
• Nasal bones – thin medially fused bones that
form the bridge of the nose
• Lacrimal bones – contribute to the medial walls of
the orbit and contain a deep groove that house
the tear ducts
Facial Bones
• Palatine bones – two bone plates that form
portions of the hard palate and contribute
to the floor of each orbit
Other Facial Bones
• Vomer – forms part of the nasal septum
• Inferior nasal conchae – paired, curved
bones in the nasal cavity that form part of
the lateral walls of the nasal cavity
Hyoid Bone
• Lies just inferior to the mandible in the anterior
neck
• Only bone of the
body that does not
articulate directly
with another bone
• Attachment point
for neck muscles
that raise and
lower the larynx
during swallowing
and speech
Figure 7.12
Vertebral Column
• 26 irregular bones (vertebrae)
• Provide a column of support, bearing the
weight of the head, neck, and trunk.
• Transfers weight to the appendicular
skeleton of the lower limbs
• Protects spinal cord
• Helps maintain an upright body position
• Approx. length of an adult column is 71cm
Vertebral Column
Cervical vertebrae
7 bones of the neck
Thoracic vertebrae
12 bones of the torso
Lumbar vertebrae
5 bones of the lower back
Figure 7.13
Vertebral Column
Sacrum - 5 fused
vertebrae
Coccyx – 4 fused
vertebrae
Figure 7.13
Disks are small shock absorbers between
the vertebrae (gel-like interior)
General Structure of Vertebrae:
1. Vertebral body (centrum) – disc-shaped,
weight-bearing region
2. Vertebral arch – composed of pedicles
(walls) and flat layers called laminae (roof)
** forms the posterior margin of each
vertebral foramen (together they form the
vertebral canal which encloses the spinal
cord)
3. Articular processes– projections on each
vertebra
Cervical Vertebrae
Table 7.2
Cervical Vertebrae
• Most mammals have 7 cervical vertebrae
(giraffes, whales, mice & humans)
• Seven vertebrae (C1-C7) are the smallest,
lightest vertebrae
Cervical Vertebrae: The Atlas
(C1)
– Holds up the head
– The superior surface articulates with the
occipital condyles of the skull (permits you to
nod)
»Has no body and no spinous process
Cervical Vertebrae: The Axis
(C2)
• The axis has a body, spine, and vertebral
arches as do other cervical vertebrae
• Articulates with the atlas to permit rotation
Figure 7.16c
Thoracic Vertebrae
• There are twelve vertebrae (T1-T12)
• Distinctive heart-shaped body (more massive than that of
a cervical vertebra)
• Each thoracic vertebra articulate with ribs
Lumbar Vertebrae
• The five lumbar vertebrae (L1-L5) are located in
the small of the back and have an enhanced
weight-bearing function
• Largest vertebrae
Tip: Mealtimes
Breakfast: 7 a.m. (7 cervical)
Lunch: 12 p.m. (12 thoracic)
Dinner: 5 p.m. (5 lumbar)
Sacrum and Coccyx
• The sacrum
– Consists of five fused vertebrae (S1-S5), which
shape the posterior wall of the pelvis
– Begin fusing after puberty and are completely
fused at age 25-30
– Protects reproductive, digestive, and urinary
organs
– It articulates with L5 superiorly, and with the
auricular surfaces of the hip bones
Coccyx
• Coccyx (Tailbone)
– The coccyx is made up of four (in some cases
three to five) fused vertebrae that articulate
superiorly with the sacrum
– Generally begun fusing by age 26
Sacrum and Coccyx
Figure 7.18a
Sacrum and Coccyx
Figure 7.18b
Bony Thorax (Thoracic Cage)
Functions:
– Forms a protective
cage around the
heart, lungs, and
great blood vessels
– Supports the
shoulder girdles
and upper limbs
– Provides
attachment for
many neck, back,
chest, and shoulder
muscles
Sternum (Breastbone)
• A dagger-shaped, flat bone that lies in the
anterior midline of the thorax
• Fusion is not complete until at least age 25 (until
this age the sternal body consist of four separate
bones)
Ribs
• There are twelve pair of ribs
• All ribs attach posteriorly to the thoracic vertebrae
• The superior 7 pair (true, or vertebrosternal ribs)
attach directly to the sternum via costal cartilages
• Ribs 8-10 (false, or vertebrocondral ribs) attach
indirectly to the sternum via costal cartilage
• Ribs 11-12 (floating, or vertebral ribs) have no
anterior attachment
Ribs
Figure 7.19a
Appendicular Skeleton
• The appendicular
skeleton is made up of
the bones of the limbs
and their supporting
elements (girdles) that
connect them to the
trunk
• Pectoral girdles attach
the upper limbs to the
body trunk
• Pelvic girdle secures
the lower limbs
Clavicles (Collarbones)
• S-shaped bones
• Small, fragile
• Smooth superior
surface lies just
beneath the skin
Figure 7.22b, c
Scapulae (Shoulder Blades)
• The scapulae are triangular, flat bones lying on
the dorsal surface of the rib cage, between the
second and seventh ribs
• Have three sides or borders (superior, medial,
and lateral) and three angles (superior, inferior,
and lateral)
Scapulae (Shoulder Blades)
Figure 7.22d, e
The Upper Limb
• Consists of the bones
of the arms, forearms,
wrists, and hands
Arm (Brachium)
• The humerus is the sole bone of the arm
• It articulates with the scapula at the
shoulder, and the radius and ulna at the
elbow
Arm
Figure 7.23 a, b
Ulna
• In anatomical position, the ulna lies medial
to the radius
• Slightly longer than the radius
• Forms the major portion of the elbow joint
with the humerus
Radius
• Lateral bone (to the ulna) of the forearm
• Thin at its proximal end, widened distally
• The superior surface of the head articulates
with the humerus
Ulna & Radius
Figure 7.24 a, b
Carpus (Wrist)
• Consists of eight carpal bones:
– Scaphoid
– Lunate
– Triquetrum
– Pisiform
– Trapezium
– Trapezoid
– Capitate
– Hamate
“Sam Likes To Push The Toy Car Hard”
Metacarpus (Palm)
• Five numbered (1-5) metacarpal bones
radiate from the wrist to form the palm
– Their bases articulate with the carpals
proximally, and with each other medially and
laterally
– Heads articulate with the phalanges
Phalanges (Fingers)
• Each hand contains 14 miniature long bones
called phalanges
• Fingers (digits) are numbered 1-5, beginning with
the thumb (pollex)
• Each finger (except the thumb) has three
phalanges – distal, middle, and proximal
• The thumb has no middle phalanx
Wrist & Hand
Pelvic Girdle (Hip)
• The hip is formed by a pair of hip bones (coxal)
• Together with the sacrum and the coccyx, these
bones form the bony pelvis
• The pelvis
– Attaches the lower limbs to the axial skeleton
with the strongest ligaments of the body
– Transmits weight of the upper body to the
lower limbs
– Supports the visceral organs of the pelvis
– Forms by the fusion of 3 bones: ilium, ischium,
and pubis
Pelvic Girdle (Hip)
Figure 7.27a
Illium
Figure 7.27b
Comparison of Male and Female Pelvic
Structure
• Female pelvis
– Tilted forward, adapted for childbearing
– True pelvis defines birth canal
– Cavity of the true pelvis is broad, shallow, and
has greater capacity
• Male pelvis
– Tilted less forward
– Adapted for support of heavier male build and
stronger muscles
– Cavity of true pelvis is narrow and deep
Comparison of Male and Female
Pelvic Structure
Table 7.4
Lower Limbs
• Each lower limb consists of a femur
(thigh), patella (knee cap), tibia & fibula
(lower leg), tarsal bones (ankle),
metatarsal (foot), and phalanges (toes)
• They carry the weight of the erect body,
and are subjected to exceptional forces
when one jumps or runs
• The sole bone of
the thigh
Femur (Thigh)
• Longest and
heaviest bone in
the body
• Articulates
proximally with
the hip and
distally with the
tibia and fibula
Figure 7.28b
Patella (Knee cap)
• Large sesamoid bone
Tibia (Shinbone)
• Large medial bone of the leg
• Receives the weight of the body from the
femur and transmits it to the foot
Fibula
• Slender bone of the leg
• Site for attachment of muscles that move
the foot and toes
Fibula
• Sticklike bone with slightly expanded
ends located laterally to the tibia
• Major markings include the head and
lateral malleolus
Tibia & Fibula
Figure 7.29a, b
Tarsus (Ankle)
• Composed of seven tarsal bones:
1.Talus
2.Calcaneus (heel bone)
3.Cuboid
4.Navicular
5.Medial Cuneiform
6.Intermediate Cuneiform
7.Lateral Cuneiform
“Tom Can Control Not Much In Life”
Tarsus
Figure 7.31b, c
Metatarsal Bones & Phalanges
• Metatarsals
– Five (I - V) long
bones
• Phalanges
– The 14 bones of
the toes
– Each digit has
three phalanges
except the hallux,
which has no
middle phalanx
Figure 7.31a
Clinical Disorders and Diseases
of the Skeletal System
Cleft Palate
• Occurs when the roof of a baby's mouth
doesn't fully develop (palatine bones fail to
fuse) leaving an opening (cleft) in the
palate that may go through to the nasal
cavity.
• It is a birth defect that happens during
pregnancy and can affect either the soft or
hard palate.
• Cleft palate is treatable, and surgery is
usually recommended.
Cleft Palate
Vertebral Column: Curvatures
Scoliosis: abnormal lateral curvature of the
spine
– Occurs most often in the thoracic region
• Most common during adolescence and girls are
more prone to developing the condition
• If muscles on one side of the body are not
functioning properly, those on the opposite side
tug on the spine and force it out of alignment
Scoliosis
Clinical Conditions
• Osteomalacia
– Literally “soft bones.”
– Includes many disorders in
which osteoid is produced but
inadequately mineralized.
• Causes can include insufficient
dietary calcium
• Insufficient vitamin D
fortification or insufficient
exposure to sun light.
• Rickets
– Children's form of osteomalacia
– More detrimental due to the fact
that their bones are still
growing.
– Signs include bowed legs, and
deformities of the pelvis, ribs,
and skull.
Osteoporosis
• Bone loss outpaces
bone regeneration
• Bones weaken and
lose mass
• Bones become brittle
and fractures occur
more often
• Found most often in
women
Age and
Bones
Osteoarthritis
•
•
•
•
Degenerative joint disease
Most common type of arthritis (21 million)
Breakdown of cartilage in joints
Mostly occurs in the weight bearing joints,
but it can occur anywhere
• Causes cartilage to become stiff and lose
its elasticity
• As cartilage deteriorates, tendons and
ligaments stretch, causing pain
Osteoarthritis
Symptoms:
•Joint aching and
soreness
•Pain after overuse or
long periods of inactivity
•Joint swelling
Fluid accumulation
Fractures
• A crack or break in a bone
• Despite its mineral strength,
bone can crack or even
break if subjected to
extreme loads, sudden
impacts, or stresses from
unusual directions
Types of Fractures
• Named according to their external
appearance, their location, and the nature
of the crack or break in the bone.
• Two general categories:
1. Closed (simple) – fracture is internal
2. Open (compound) – fracture projects
through the skin
Common fracture types (cont’d)
Common fracture types
• Comminuted fractures
• Spiral fractures
Figure 6–16 (4 of 9)
• Greenstick fracture
Figure 6–16 (7 of 9)
• Compression
fractures
Figure 6–16 (9 of 9)
Depression fracture of the skull
X-ray & MRI
How do they work???
Steps in the Repair of a Fracture
Step 1 –
• Immediately after the fracture, extensive
bleeding occurs (blood vessels are broken).
• A large blood clot, or fracture hematoma, soon
closes off the injured vessels and leaves a
fibrous meshwork in the damaged area.
• The disruption of the circulation kills osteocytes
(mature bone cells) around the fracture.
• Dead bone soon extends along the shaft.
Steps in the Repair of a Fracture
Step 2 –
• The cells of the endosteum (cellular layer) and
periosteum undergo cell division and the
daughter cells migrate into the fracture zone.
• An external callus (hard skin) forms and
encircles fracture
• An internal callus organizes within the cavity
and between the broken ends of the shaft
• The broken ends have been temporarily
stabilized
Steps in the Repair of a Fracture
Step 3 –
• Osteoblasts (bone building cells) replace the
central cartilage of the external callus with
spongy bone
• Calluses form a brace at the fracture site
• Spongy bone now unites the broken ends
• Fragments of dead bone are removed and
replaced
• If the fracture required a cast, it can be removed
at this stage
Steps in the Repair of a Fracture
Step 4 –
• Osteoclasts (remove and recycle bone matrix)
and osteoblasts continue to remodel the region
of the fracture (4 months to 1 year)
• When remodeling is complete, the bone of the
calluses is gone and only living compact bone
remains.
• The bone could be slightly thicker and stronger
than normal at the fracture site
Fracture repair
Fracture repair (cont’d)
Casts
• Holds a broken bone in place as it heals
• Help to prevent or decrease muscle
contractions
• Provide immobilization (the joints above
and below the area)
• Casts are made of plaster and fiberglass
• Typically worn for 6-8 weeks
Treatment of a Fracture
• Initial treatment for fractures of arms, legs,
hands, and feet include splinting the
extremity in the position it is found,
elevation, and ice.
• Edema (what does this have to do with
splinting and casting?)
• Closed Reduction – manual realignment
• Open Reduction – surgically realignment
Joints (Articulations)
• Where two bones interconnect
• The structure of a joint determines the type
and amount of movement that may occur
• Functions
– Give the skeleton mobility
– Hold the skeleton together
Joint Facts
• 400 + joints
• Approximately 230 movable and semimovable joints
• Muscles span joints, crossing from 1 bone
to another
• When muscles contract, they tug on the
bones, producing movement at the joint
Classification of Joints:
Structural/Functional
• The three structural classifications are:
– Immovable (synarthrosis)
– Slightly movable (amphiarthrosis)
– Freely movable (diarthrosis) or synovial joint
lmmovable Joints
• The bones are close together and may
interlock
• Extremely strong joints
• There is no joint movement
Examples:
1. Suture – skull
2. Binds the teeth to bony
sockets in jaw
3. Bridge between two
articulating bones (first
pair of ribs and the
sternum)
Figure 8.1a
Immovable Joints
Figure 8.2b
Slightly Movable Joints
• Permits movement
• Stronger than a freely
movable joint
• Articulating bones are
connected by cartilage
or collagen fibers
• Example: articulation
between the two pubic
bones
Figure 8.2a
Synovial (Freely Movable) Joints
• Permit a wider range of motion
• Typically located at the ends of long bones
• Examples: upper and lower limbs
Synovial Joints: General Structure
• Synovial joints all
have the
following:
– Articular cartilage
– Joint (synovial)
cavity
– Articular capsule
– Synovial fluid
– Reinforcing
ligaments
Figure 8.3a
Synovial Joints: General
Structure
• The surfaces of the articular cartilage are
slick and smooth
• Articular cartilages are separated by a thin
film of synovial fluid
• How are these two features important
when it comes to movement?
Synovial Joints: Accessory
Structures
• Synovial Fluid – lubrication, nutrient
distribution, shock absorption
• Cartilage – shock absorption, subdivide
• Fat Pads – protection, packing material
• Ligaments – support, strength
• Tendons – limit ROM, support
• Bursae – reduce friction, shock absorption
Synovial Joints: Movement/ROM
• Muscle attachment across a joint
– Origin – attachment to the immovable bone
– Insertion – attachment to the movable bone
•Nonaxial – slipping movements only
•Uniaxial (monaxial) – movement in one
plane
•Biaxial – movement in two planes
•Multiaxial – movement in or around all
three planes
Types of Synovial Joints
• Based on the shapes of the articular
surfaces
• Each type of joint permits a different type
and range of motion
Types:
• Gliding
• Hinge
• Pivot
• Condylar
• Saddle
• Ball and socket
Types of Synovial Joints
• Gliding (Plane)
joints
– Articular surfaces
are essentially flat
– Allow only
slipping or gliding
movements
– Examples:
clavicle, carpals,
tarsals, sacrumiliac
Figure 8.7a
Types of Synovial Joints
• Hinge joints
– Cylindrical projections of
one bone fits into a
trough-shaped surface
on another
– Motion is along a single
plane
– Examples: elbow, knee,
ankle, and
interphalangeal joints
Figure 8.7b
Pivot Joints
• Rounded end of one bone
protrudes into a “sleeve,”
or ring, composed of bone
(and possibly ligaments) of
another
• Permit only rotation
• Examples: joint between
the axis and the dens
(neck), and the proximal
radioulnar joint
Figure 8.7c
Condyloid (Ellipsoid) Joints
• Oval articular surface of
one bone fits into a
complementary
depression in another
• Biaxial joints permit
movement around two
axes (flexion/extension
and abduction/adduction)
• Examples: radiocarpal
(wrist) joints, and
metacarpophalangeal
(knuckle) joints
Figure 8.7d
Saddle Joints
• Similar to condyloid
joints but with greater
movement
• Each articular surface
has both a concave
and a convex surface
• Allows circumduction
but prevents rotation
• Example:
carpometacarpal joint
of the thumb
Figure 8.7e
Ball-and-Socket Joints
• A spherical or
hemispherical head of
one bone articulates
with a cuplike socket
of another
• Multiaxial joints permit
the most freely
moving synovial joints
• Examples: shoulder
and hip joints
Figure 8.7f
Bone Bingo
Frontal
Lacrimal
Clavicle
Sternum
Humerus
Phalanges
Patella
Metatarsals
Coccyx
Zygomatic
Mandible
Scapula
Vertebrae
Radius
Femur
Fibula
Metacarpals
Occipital
Nasal
Maxilla
Ribs
Ulna
Carpals
Tibia
Tarsals
Sacrum
Parietal