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
Divisions of the Skeleton
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
Terms used to describe skeletal structures: