Skeletal System Functions Support framework of the body

Skeletal System

Functions • Support- framework of the body • Movement- many of the muscles attach to the skeleton • Protection- protects vital organs injury • Mineral Reservoir- calcium, phosphorus, sodium, potassium, and other minerals stored in the bones. • Hemopoiesis- following birth, red marrow produce blood cells found in circulatory system.

Skeletal Organization • Axial Skeleton – – Skull Hyoid bone Vertebral column Thoracic cage • Appendicular Skeleton – – Pectoral girdle Upper limbs Pelvic girdle Lower limbs

Structure of Bones • Diaphysis- bone shaft (femur, tibia, ulna) – Compact bone- tightly packed together tissue, is solid, strong, and resistant to bending. – Medullary cavity- yellow marrow, fat storage area. Inactive in blood cell production. – Endosteum- thin layer of connective tissue that lines medullary cavity.

• Epiphysis- two ends of the shaft. – Compact bone- outer surfaces – Spongy bone- red marrow that functions in prod. red blood cells, certain white blood cells, and platelets. • Red because of oxygen carrying pigment called hemoglobin.

Microscopic Parts of a Bone • Haversian Canal- contains at least one blood capillary which is source for nutrients and means of waste disposal. • Lacunae- small cavities or spaces that contain a cell. • Osteocyte- bone cell • Canaliculi- canals that link one lacuna to another.

Fractures • Compound- broken bone sticks out of skin • Simple- break that does not come through the skin

Types of Breaks • Transverse- break • Longitudinal- fracture occurs at a right angle splits bone lengthwise • Oblique- break occurs • Greenstickat an angle other then incomplete fracture in right. the long axis of the bone. • Spiral- spiral or sshaped; caused by a • Compression- bones twisting action are pressed together.

• Depressed- fracture due to denting in a bone. • Impacted- broken ends are jammed together. • Comminuted- produced by severe, direct violence; three or more fragments.

Body Movements • Flexion- bending parts at a joint so angle is closer together. ( bending knee) • Extension- straightening parts at a joint so angle increases. (straightening knee) • Dorsiflexion- bending the foot at the ankle toward the shin. • Plantar flexion- bending the foot at the ankle toward the sole. (downward)

• Hyperextension- excess extension of the parts at a joint, past the normal position. • Abduction- moving a part away from the midline (lift arm to form right angle) • Adduction- moving a part toward the midline (returning arm to the side of the body) • Rotation- moving a part around an axis (head)

• Circumduction- moving a part so that its end follows a circular path. (moving finger in circle w/o moving hand) • Pronation- turning body part so that it is facing downward (posterior) • Supination- turning a body part so that it is facing upward (anterior) • Eversion- turning the foot so that the sole faces laterally. (out)

• Inversion- turning the foot so that the sole faces medially (in) • Retraction- moving a part backward • Protraction- moving a part forward • elevation- raising a part (shrugging shoulders) • Depression- lowering a part (drooping shoulders)