Chapter 5: The Skeletal System Lecture Notes Part B Bone Fractures • Fracture—break in a bone • Types of bone fractures • Closed (simple) fracture—break that does not penetrate the skin • Open (compound) fracture—broken bone penetrates through the skin • Bone fractures are treated by reduction and immobilization Common Types of Fractures Table 5.2 Rickets: • Disease in children where bones fail to calcify: • Bones soften and weight bearing bones will bow • Caused by lack of calcium or vitamin D Repair of Bone Fractures • Hematoma (blood-filled swelling) is formed • Break is splinted by fibrocartilage to form a callus • Fibrocartilage callus is replaced by a bony callus • Bony callus is remodeled to form a permanent patch Stages in the Healing of a Bone Fracture Hematoma Internal callus (fibrous tissue and cartilage) External callus Bony callus of spongy bone New blood vessels Healed fracture Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation Bone remodeling Stages in the Healing of a Bone Fracture Hematoma Hematoma formation Figure 5.5, step 1 Stages in the Healing of a Bone Fracture Hematoma External callus Internal callus (fibrous tissue and cartilage) New blood vessels Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Figure 5.5, step 2 Stages in the Healing of a Bone Fracture Hematoma External callus Internal callus (fibrous tissue and cartilage) Bony callus of spongy bone New blood vessels Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation Figure 5.5, step 3 Stages in the Healing of a Bone Fracture Hematoma Internal callus (fibrous tissue and cartilage) External callus Bony callus of spongy bone New blood vessels Healed fracture Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation Bone remodeling Figure 5.5, step 4 The Axial Skeleton • Forms the longitudinal axis of the body • Divided into three parts • Skull • Vertebral column • Bony thorax The Axial Skeleton Figure 5.6a The Axial Skeleton Figure 5.6b The Skull • Two sets of bones • Cranium • Facial bones • Bones are joined by sutures • Only the mandible is attached by a freely movable joint Human Skull, Lateral View Figure 5.7 Human Skull, Superior View Figure 5.8 Human Skull, Inferior View Figure 5.9 Human Skull, Anterior View Figure 5.11 Paranasal Sinuses • Hollow portions of bones surrounding the nasal cavity • Functions of paranasal sinuses • Lighten the skull • Give resonance and amplification to voice Paranasal Sinuses Figure 5.10a Paranasal Sinuses Figure 5.10b The Hyoid Bone • The only bone that does not articulate with another bone • Serves as a moveable base for the tongue • Aids in swallowing and speech The Hyoid Bone Figure 5.12