Anatomy Practical
[PHL 212]
Skeletal System
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Composed of the body’s bones and associated ligaments, tendons, and
cartilages.
FUNCTIONS:
1. Support
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The bones of the legs, pelvic girdle, and vertebral column support the weight of the erect
body.
The mandible (jawbone) supports the teeth.
2. Protection
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The bones of the skull protect the brain.
Ribs and sternum (breastbone) protect the lungs and heart.
Vertebrae protect the spinal cord.
3. Movement
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Skeletal muscles use the bones as levers to move the body.
4. Reservoir for minerals and adipose tissue
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99% of the body’s calcium is stored in bone.
85% of the body’s phosphorous is stored in bone.
Adipose tissue is found in the marrow of certain bones.
5. Hematopoiesis
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Blood cell formation (An average of 2.6 million red blood cells are produced each second by
the bone marrow ).
Skull
Middle ears
Hyoid bone
Vertebral column
Thoracic cage
22 bones (8 Cranial + 14 Facial)
6
1
26 (7 + 12 + 5 + 1 + 1)
25
Pectoral girdle
Upper limbs
Lower limbs
Pelvic girdle
4
60
60
2
Total bones
206
Axial Skeleton (supports and protects organs of head, neck and
trunk)
 Skull
(cranium and facial bones)
 Hyoid bone
 Vertebral Column
(vertebrae and disks)
 Thoracic cage
(ribs and sternum)
Appendicular Skeleton
 Upper Limb Bones
 Pectoral girdle
 Lower Limb Bones
 Pelvic girdle
(arms)
(clavicles and scapulae)
(legs)
(coxal bones)
Classification of Bones on the Basis of
Shape
Cranial Bones
 Frontal
 Parietal
 Temporal
 Occipital
 Sphenoid
 Ethmoid
Facial Bones
 Mandible
 Maxilla
 Palatine
 Zygomatic
 Nasal
 Lacrimal
 Vomer
 Turbinate
The Hyoid Bone
 The only bone that does
not articulate with another
bone
 Serves as a moveable
base for the tongue
The vertebral column consists of a series of irregularly
shaped bones, called vertebrae. Each vertebrae is given a
name according to its location.
The vertebral column can be broken up into four sections.
 Neck - 7 Cervical vertebrae
 Thorax - 12 Thoracic vertebrae
 Abdomen - 5 Lumbar vertebrae
 Pelvis - Sacrum (5 fused vertebrae) and Coccyx (4 fused
vertebrae)
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Vertebrae separated by intervertebral discs
Vertebrae vary in size and morphology
Structure of a Typical Vertebrae
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To protect major organs
Made-up of three parts: Ribs, Sternum, Thoracic
vertebrae
Ribs
◦ Ribs give the chest its familiar shape.
◦ Protect the heart and lungs from injuries and shocks.
◦ Also protect parts of the stomach, spleen, and kidneys.
◦ Help you to breathe.
Sternum (Manubrim, Body, Xiphoid process)
Thoracic vertebrae
The Appendicular Skeleton
 Limbs (appendages): Upper & Lower
 Pectoral girdle
 Pelvic girdle
The Appendicular Skeleton
Arm
 Forearm
 Hand
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:Humerus
:Radius & ulna
:Carpals, metacarpals, phalanges
Bones of the Upper Limb (The Arm)
Bones of the Upper Limb (The Forearm)
Bones of the Upper Limb (The Hand)
The hand
 Wrist: Carpals (8)
 Palm: Metacarpals (5)
 Fingers: Phalanges (14)
The Pectoral (Shoulder) Girdle
 Composed of two bones
 Clavicle – collarbone
 Scapula – shoulder blade
 These bones allow the upper limb to have
exceptionally free movement
Bones of the Shoulder Girdle
 Femur
 Tibia,
fibula
 Tarsals, metatarslas, phalanges
 Patella
Bones of the Lower Limbs (Thigh)
Bones of the Lower Limbs (Leg)
Bones of the Lower Limbs (Foot)
 The foot (26 bones)
 Ankle: Tarsus (7)
 Sole: Metatarsals (5)
 Toes: Phalanges (14)
Bones of the Lower Limbs (Patella)
Bones of the Pelvic Girdle (Hip girdle)
 Coxal bones (Hip), innominate bone
 Composed of three pair of fused bones
 Ilium
 Ischium
 Pubic bone
 The total weight of the upper body rests on the pelvis
 Protects several organs
 Reproductive organs
 Urinary bladder
 Part of the large intestine
 The developing fetus in a pregnant woman
The Pelvic Girdle
Gender Differences of the Pelvis
Joints
 Articulations of bones
 Functions of joints
 Hold bones together
 Allow for mobility
 Classification:
 Functionally
 Structurally
1.
Immovable (synarthroses):
Bones sutured together by fibrous connective tissue:
e.g. Suture in the skull between skull bones
2.
Slightly movable (amphiarthroses):
Connected by fibrocartilage or hyaline cartilage:
e.g. vertebrae, rib/sternum joint, pubic symphysis
3.
Freely movable (diarthrosis):
Have joint cavity filled with synovial fluid
 ligaments- hold bones together
 tendons- muscle to bone
 lined by synovial membrane
Structural Classification of Joints
 Fibrous joints
 Generally immovable
 Cartilaginous joints
 Immovable or slightly moveable
 Synovial joints
 Freely moveable
Fibrous Joints [Synarthrosis or immovable]
 Bones joined by fibrous connective tissue
 Example: Suture in the skull between skull bones
Cartilaginous Joints- Amphiarthrosis
 Bones connected by hyaline or fibro cartilage
 Examples: Pubic symphysis, Intervertebral
joints, ribs sternum joint
Synovial Joints- Diarthroses
 Have a joint cavity filled with synovial fluid
 Hyaline cartilage covers the ends of bones
a.
b.
c.
d.
e.
f.
Gliding: Sliding and twisting. E.g. wrist and ankle joints
Hinge: up and down movement in one plane. E.g. knee and
elbow joints
Pivot: Allow rotation around an axis. E.g. The neck and
forearms. In the neck the occipital bone spins over the top of
the axis. In the forearms the radius and ulna twist around each
other.
Condyloid: Movement in different planes but not rotations.
E.g. Between metacarpals and phalanges
Saddle: Allows movement back and forth and up and down,
but does not allow for rotation like a ball and socket joint.
E.g. Carpal and metacarpal bones of thumb
Ball and socket: Allows for radial movement in almost any
direction. E.g. Shoulder and hip joints
Types of Synovial Joints Based on Shape
Types of Synovial Joints Based on Shape
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Flexion: move lower leg toward upper
Extension: straightening the leg
Abduction: moving leg away from body
Adduction: moving leg toward the body
Rotation: around its axis
Supination: rotation of arm to palm-up position
Pronation:palm down
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Inversion: turning foot so sole is inward
Eversion: sole is out
Elevation and depression: raising body part up or down