166 CHAP T ER 4 Review LESSON 4.1 Bone as a Living Tissue Key Points • The five functions of the skeletal system are support, protection, movement, storage, and blood cell formation. • The five categories (by shape) of bones are long bones, short bones, flat bones, sesamoid bones, and irregular bones. • Remodeling of bones continues throughout life to keep bones strong. LESSON 4.2 The Axial Skeleton Key Points • The skull contains eight cranial bones and fourteen facial bones. • The five sections of the vertebral column, or spine, are the cervical region, thoracic region, lumbar region, sacrum, and coccyx. • The thoracic cage, which protects the heart and lungs, is made up of the ribs, sternum, and thoracic vertebrae. LESSON 4.3 The Appendicular Skeleton Key Points • The upper extremity includes the pectoral girdle, arms, wrists, and hands the pectoral girdle includes the clavicles and scapulae. • The lower extremity, which includes the pelvic girdle, legs, ankles, and feet, is designed for weight-bearing and gait. Key Terms articular cartilage bone marrow cortical bone diaphysis endosteum epiphyseal plate epiphysis Haversian canals Haversian system hematopoiesis lacunae medullary cavity ossification osteoblasts osteoclasts osteocytes osteon perforating (Volkmann’s) canals periosteum remodeling trabecular bone Key Terms atlas axial skeleton axis cervical region coccyx cranium facial bones fontanel intervertebral discs lumbar region mandible maxillary bones process sacrum skull sternum sutures thoracic cage thoracic region vertebra vomer Key Terms appendicular skeleton carpal bones clavicle femur fibula humerus lower extremity metacarpal bones metatarsal bones patella pectoral girdle pelvis phalanges radius scapula tarsal bones tibia ulna upper extremity Copyright Goodheart-Willcox Co., Inc.