chap 6.2 bone classification terms

long bones

One that is cylindrical in shape, being longer than it is wide. Long bones function as levers; they move when muscles contract

They are found in:

• Arms (humerus, ulna, radius)

• Legs (femur, tibia,fibula)

• Fingers (metacarpals, phalanges)

• Toes (metatarsals, phalanges)

Short bones

Is one that is cube-like in shape, being approximately equal in length, width, and thickness.

Function: provide stability and support as well as some limited motion

Found in:

• carpals of the wrist

• Tarsals of the ankles

Flat bone

Typically thin but often curved.

Function: serve as points of attachment for muscles and often protect internal organs

Found:

• cranial (skull) bones

• Scapulae (shoulder blades)

• Sternum (breastbone)

• Ribs

Irregular bones

Is one that does not have any easily characterized shape and therefore does not fit any other classification. These bones tend to have more complex shapes

Found:

• vertebrae that support spinal cord

• Many facial bones particularly the ones containing sinuses

Sesamoid bones

Is a small, round bone that, as the name suggests, is shaped like a sesame seed. These bones form in tendons where a great deal of pressure is generated in a joint. Vary in number and placement

Function: protect tendons by helping them overcome compressive forces.

Found:

• tendons associated with the feet, hands and knees

• The patellae (found in all people)