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Chapter 7. Skeletal Organization. Number of Bones. Average number of bones is 206 People may have varying numbers of bones Ex – sutural bones, sesamoid bones in tendons. Divisions of the Skeleton. Axial skeleton
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Chapter 7 Skeletal Organization
Number of Bones • Average number of bones is 206 • People may have varying numbers of bones • Ex – sutural bones, sesamoid bones in tendons
Divisions of the Skeleton • Axial skeleton • Bony and cartilaginous parts that support and protect the organs of the head, neck, and trunk • Appendicular skeleton • Bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeletion
Axial Skeleton • Skull • Includes cranium and facial bones • Hyoid Bone • Located in neck between lower jaw and the larynx • Does not articulate with any other bones (held in place by muscles and ligaments) • Supports the tongue • Serves as an attachment point for muscles associated with the tongue
Axial Skeleton • Vertebral Column • Consists of vertebrae separted by cartilaginous vertebral discs • Five vertebrae near the distal end are fused to form the sacrum (part of the pelvis) • Four vertebrae are fused to form the tailbone (coccyx) below the sacrum • Thoracic Cage • Protects the organs of the thorax and upper abdomen • Consists of 12 pairs of ribs (which articulate with the thoracic vertebrae) and the sternum (with which most ribs articulate anteriorly)
Appendicular Skeleton • Pectoral Girdle • Formed by the scapula and the clavicle • Connects the bones of the upper limbs to the axial skeleton • Aid in upper limb movements • Upper Limbs • Consists of humerus, radius, ulna, and hand bones • The humerus, radius, and ulna articulate at the elbow joint • The hand consists of 8 carpals, 5 metacarpals, and 14 phalanges
Appendicular Skeleton • Pelvic Girdle • Formed by two hipbones (coxae) which attach to the sacrum posteriorly and each other anteriorly • Connects the bones of the lower limbs to the axial skeleton • Forms the pelvis with the sacrum and coccyx • Protects the lower abdominal and reproductive organs • Lower Limbs • Consists of the femur, tibia, fibula, and foot • The femur and tibia articulate at the knee joint which is covered by the patella • The foot contains 7 tarsals, 5 metatarsals, and 14 phalanges