Download Laboratory Exercise 7: The Skeletal System The skeletal system is a

Laboratory Exercise 7: The Skeletal System
The skeletal system is a system that functions to:
Protects the vital organs of the body from injury,
Provides leverage and attachment for the skeletal muscles, making body movements possible,
Acts as a supportive framework for the body,
Serves as a reservoir of calcium and phosphorus salts,
Functions as a site for hemopoiesis (blood cell production).
The Anatomical. Position
The reference posture is the anatomical position.
The body is standing erect and facing forward, upper limbs are fully extended with palms facing forward; lower
limbs are fully extended, the feet squarely on the ground.
Regional or Positional and Directional terms assume that the body is in the anatomical position.
Body Planes
The body is sectioned through various planes which are at right angles to each other..
Mid-sagittal plane – is a long section that divides the body into equal right and left portions.
Parasagittal plane – is a long section that divides the body into unequal right and left portions.
Frontal (coronal) plane - divides the body into front and back portions.
Horizontal (cross or transverse) plane - divides the body into upper and lower portions. Horizontal sections are
made perpendicular to the longitudinal axis of the structure.
A. Axial Skeleton
The axial skeleton functions for support and protection.
The skull bones are fused together by interlocking immovable joints, called sutures.
The vertebral column has 4 curves which creates an S-shaped configuration that functions to position the
body weight over the legs, increases the shock absorber capacity of the vertebral column and provide
flexibility to the trunk of the body. These 4 curvatures develop during early childhood.
At birth, the newborn lacks convex curvatures, just a large continuous concave anterior curvature. This
concave curvature is made up of the two primary curvatures, the thoracic and sacral curvatures.
head
thoracic
sacral
At 3 months the first secondary curvature, the cervical curve develops.
cervical
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The Pelvis
The pelvis = pelvic girdle (2 os coxa) + sacrum + coccyx
Sex Differences between female and male pelves.
The differences are due to pregnancy and childbirth.
Point of Comparison
Female
Male
Greater pelvis
Wide, Shallow
Bones larger, heavier and more
prominent bone markings,
Deep
Pelvic brim (inlet)
Larger and
elliptical (oval)
Narrow, deep
funnel or heart shaped
Angle of pubic arch
Greater than 90o
(obtuse)
Less than 90o
(acute)
Pelvic width
Large
Small
Ilium
Less vertical
More vertical
Iliac fossa
Shallow
Deep
Iliac crest
Less curved
More curved
Acetabulum
Small
Large
Obturator foramen
Oval
Round
False pelvis – superior to the arcuate line, not entirely surrounded by bone, supports the abdominal viscera.
True pelvis- inferior to the arcuate line, entirely surrounded by bone. Dimensions of the true pelvis, inlet and
outlet, are critical to normal childbirth.
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Axial Skeleton
Skull - Cranium and Face
Cranium (8 bones)
Face (14 bones)
Frontal bone (1)
Mandible (1)
Coronal Suture – articulation of parietal bones with frontal bone
Body
Parietal bone (2)
Ramus
Sagittal Suture – articulation of the parietal bones
Mandibular (Condylar) process
Temporal bone (2)
Coronoid process
Squamosal Suture – articulation of parietal bones with temporal bones
Angle
Zygomatic process of temporal bone
Alveolar margin
Mandibular fossa
Maxilla (2)
External auditory meatus (canal)
Alveolar margin
Styloid process
Palatine process of maxilla
Mastoid process
Palatine bone (2)
Jugular foramen
Zygomatic bone (2)
Carotid canal
Temporal process of zygomatic bone
Occipital bone (1)
Lacrimal bone (2)
Lambdoidal Suture – articulation of parietal bones with occipital bone Lacrimal fossa
Foramen magnum
Nasal bone (2)
Occipital condyle
Vomer (1)
External occipital protuberance
Inferior Nasal Conchae (2)
Sphenoid bone (1)
Greater wing of Sphenoid bone
Hyoid
Sella turcica
Lesser wing of Sphenoid bone
Optic canals
Ethmoid bone (1)
Crista galli
Cribriform plate with olfactory foramina
Perpendicular plate
Lateral Masses
Superior and Middle Conchae
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Appendicular Skeleton
Pectoral Girdle
Clavicle – acromial (lateral) end flat, sternal (medial) end round
Scapula
Spine
Acromion
Coracoid process
Glenoid fossa
Articulations
Lateral– acrominoclavicular joint
Medial – sternoclavicular joint
Upper Limb
Humerus
Head
Neck
Greater Tubercle
Lesser Tubercle
Intertubercular (Bicepital) groove
Deltoid tuberosity
Radial groove – runs obliquely, path for radial nerve, inferior to the deltoid tuberosity
Lateral Epicondyle
Medial Epicondyle
Capitulum (Lateral Condyle)
Trochlea (Medial Condyle)
Coronoid fossa (anterior surface)
Olecranon fossa (posterior surface)
Radial fossa
Radius
Head
Radial tuberosity
Styloid process
Ulna notch – distal radioulnar joint
Ulna
Olecranon process (posterior surface)
Trochlear (Semi-Lunar) notch
Coronoid process (anterior surface)
Radial notch – proximal radioulnar joint
Head
Styloid process
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Hand
Carpels (8, 2 rows of 4 each)
Lateral
Proximal Row
to Medial
Navicular (Scaphoid)
Lunate
Triquetral (Triangular)
Pisiform
Metacarpels (5)
Phalanges (14)
Proximal Phalanx
Middle Phalanx, except for Thumb or Pollex
Distal Phalanx
Distal Row
Trapezium
Trapezoid
Capitate
Hamate
Pelvic Girdle
Ilium
Auricular surface articulates with the sacrum at the sacroiliac joint
Alae
Iliac fossa
Iliac crest
Anterior superior iliac spine
Anterior inferior iliac spine
Posterior superior iliac spine
Posterior inferior iliac spine
Greater sciatic notch
Arcuate line – outline of the pelvic brim
Ischium
Ischial spine
Lesser sciatic notch
Ischial tuberosity
Pubis
Pubic Symphysis
Pubic tubercle
Pubic crest
Arcuate line
Obturator foramen – forms the space in the os coxa Its superior margin is formed by fusion of superior ramus
of pubis and body of ischium. Its inferior margin is formed by fusion of inferior ramus of
pubis and ischial ramus.
Acetabulum – deep hemispheric socket formed by fusion of ilium, ischium and pubis
Lower Limb
Femur
Head of femur – articulates with acetabulum of os coax
Fovea capitis
Neck of femur
Shaft of femur
Greater Trochanter (lateral)
Lesser Trochanter (medial)
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The common structural features of the human pectoral and pelvic (appendicular) girdles.
Both girdles attach the limbs to the axial skeleton and serve as points of attachment for axial and appendicular
muscles. Both girdles at the shoulder and hip joints are ball and socket joints.
Structural differences of the human pectoral and pelvic girdles related to their functions.
The structure of the pectoral girdle relates to its functions of mobility and flexibility.
a. Pectoral girdle bones are light. The pectoral girdle is made up of two separate bones – clavicle and
scapula.
b. The sternoclavicular joints are the anterior sites of attachment of the pectoral girdle to the axial skeleton.
These joints allow the clavicles to move in longitudinal and transverse planes.
c. The scapula has no direct posterior attachment to the thorax, it is held loosely in place by the posterior
axial muscles. This allows the scapula to slide back and forth against the thorax during muscular
activity.
d. The glenoid cavity is a shallow socket, which does little to stabilize the head of the humerus to the
scapula. In the glenohumeral joint the ligaments do not attach the humerus tightly to the scapula. This
joint permits the humerus to move freely in the longitudinal, transverse and rotational planes.
The structure of the pelvic girdle relates to its function of weight bearing rather than mobility and flexibility.
a. Pelvic girdle bones are heavy and massive. The pelvic girdle bones (os coxa) are formed from a fusion of
three bones – ilium, pubis and ischium.
b. The sacroiliac joints are the posterior sites of attachments of the pelvic girdles to the axial skeleton. This
joint allows the pelvic girdles slight gliding movement.
c. The anterior joint between the pelvic girdles (pubic symphysis) also permits slight movement.
d. The acetabulum is a deep socket that stabilizes the head of the femur to the pelvic girdle. In the coxal
(hip) joint the ligaments strongly attach the femur to the pelvic girdle to ensure a strong, stable limb
attachment. This joint allows movement in all planes, but not as freely as in the shoulder joint.
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