Functions of the Bones
- Support; the "steel girders" and "reinforced concrete" of the body, form the internal framework that supports the body and cradles its soft organs
- Protection; bones protect soft body organs
- Movement; skeletal muscles, attached to bones by tendons, use the bones as levers to move the body and its parts
- Storage; fat is stored in the internal (marrow) cavities of bones ; bones itself serves as a storehouse for minerals, the most important of which are calcium and phosphorus
- Blood Cell Formation; occurs within the marrow cavities of certain bones
Classification of Bones
- compact bone; dense and looks smooth and homogeneous
- spongy bone; composed of small needle pieces of gone and lots of open space
- long bones; typically longer than they are wide ; they have a shaft with heads at both ends ; they are mostly compact bones
- short bones; generally cube shaped and contain mostly spongy bone
- flat bones; thin, flattened, and usually curved ; two thin layers of compact bone sandwiching a layer of spongy bone between them
- irregular bones; bones that do not fit one of the preceding categories
Bone Formation, Growth, and Remodeling
- ossification; process of bone formation ; involves two major phases
- osteoblasts; bone forming cells
- osteoclasts; giant bone-destroying cells in bones
- bone remodeling; essential s bones are to retain normal proportions and strength during longbone growth as the body increases in size and weight
Bone Markings
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Bone Fractures
Axial Skeleton
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Vertebral Column (Spine)
Thoracic Cage
Bones of the Shoulder Girdle
Bones of the Upper Limbs
Bones of the Pelvic Girdle
Bones of the Lower Limbs
Joints
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Types of Synovial Joints Based on Shape
- plane joint
- the articular surfaces are essentially flat, and only short slipping or gliding movements are allowed
- nonaxial
- example; the intercarpal joints of the wrist
- hinge joint
- the cylindrical end of one bone fits into a trough-shaped surface on another bone
- uniaxial
- examples; elbow joint, ankle joint, the joints between the phalanges of the fingers
- pivot joint
- the rounded end of one bone fits into a sleeve or ring of bone
- uniaxial joints
- examples; proximal radioulnar joint and the joint between the atlas and the dens of the axis
- condylar joint
- egg-shaped articular surface of one bone fits into an oval concavity in another
- allow the moving bone to travel from side to side and back and forth, but the bone cannot rotate around its long axis
- biaxial
- example; metacarpal and phalanx
- saddle joints
- each articular surface has both convex and concave areas
- biaxial
- examples; carpal and metacarpals in the thumb
- ball and socket joint
- the spherical head of one bone fits into a round socket in another
- examples; shoulder and hip
- multiaxial