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Osteology. Functions of the Skeleton. 1. Protection Protect vital and delicate soft-tissue structures from injury. Skull and the rib cage. 2. Support The skeletal system provides the support necessary to safely maintain an upright posture. 3. Movement
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Functions of the Skeleton • 1. Protection • Protect vital and delicate soft-tissue structures from injury. • Skull and the rib cage.
2. Support • The skeletal system provides the support necessary to safely maintain an upright posture. • 3. Movement • Bones serve as points of attachment for muscles. • As muscles contract, bones act as levers. • Joints serve as pivot points that allow actual movement.
Classifications of Bones • Divided into five groups. • 1. Long bones • 2. Short bones • 3. Flat bones • 4. Irregular bones • 5. Sesamoid bones
Primarily serve as levers. • Femur • Humerus • Radius • Ulna • Tibia • Fibula
Wrist and ankle • Tend to be cube shaped and are generally found in areas which only very limited motion is required. • Principle function is to provide strength.
Consist of parallel, platelike layers of hard or compact bone . • Provide large areas for muscle attachment. • Protection.
Bones that have obvious peculiarities in their shape are placed in this classification. • Unique in appearance and function. • Spine • Pelvis • Ossicles of the ear.
Small and rounded and triangular bones usually develop within the substance of tendons and fascial tissue. • Found adjacent to joints. • Named after their resemblance to sesame seeds.
Features of a Typical Bone • Every bone in the skeleton is a unique organ – a distinct structural unit. • Long bones uniformly possess many of the features of bones in general.
Organization of the Skeleton • The 206 bones of the adult skeleton are grouped into two subdivisions: • 1. Axial Skeleton (80) bones. • 6 tiny middle ear bones • 74 bones that form the upright axis of the body • Skull, vertebral column, and thorax (sternum and ribs)
Appendicular skeleton (126 bones) • Form the appendages and the girdles that attach them to the axial skeleton. • Shoulder girdles, arms, wrists, hands, hip girdles, legs, ankles, and feet.
Differences Between Male and Female Skeletons • Male skeleton is larger and heavier. • The male pelvis is deep and funnel-shaped, the female pelvis is shallow, broad, and flaring. • Bones of the male lower extremity tend to be longer.
Classification of Joints • Classified into three major groups or types. • 1. Synarthroses (immovable joints) • 2. Amphiarthroses (slightly moveable joints) • 3. Diarthroses (freely movable joints)
Diarthroses • Often called synovial joints. • Characterized by the presence of a closed cavity between the bones that make up the joint. • Functionally the most important. • Most complex structure and are most vulnerable to injury.
Six varieties of diarthroticjoints. • Classified according to the shapes of the articular surfaces between bones. • 1. ball and socket • 2. hinge joints • 3. condyloid or ellpsoid joints • 4. saddle joints • 5. pivot joints • 6. gliding joints