Part 2 - Proximal Limb Bones | BCTC

Part 2: Proximal Long Bones of the Limbs

In order to facilitate comparison between similar bones and to highlight similarities in structure and names of markings, I have put the two bones of the proximal portion of each limb (humerus and femur) together rather than featuring one limb at a time. Both anterior and posterior surfaces are shown. To examine one limb at a time, and how bones connect, review your lab manual and A Brief Atlas of the Human Body.

The markings for which you are responsible are listed in Lab Exercise 7.

You will also need to be able to distinguish left from right for both of these bones.

Identification: These two bones both are large and have a distinct rounded head, allowing for a great range of movement. The femur has a distinct neck separating the head from the rest of the bone, while the humerus lacks such a neck.

Determining side: In order to distinguish right from left, first orient the bones so that the rounded head is superior (up) and pointing medially (toward the body's midline). Then you will need to determine the anterior vs. posterior side. On the femur, look for the patellar surface, which is anterior. Also note how the articulating surfaces of the condyles extends far back on the posterior side (since the knee bends back but not forward). On the humerus, look for the deep olecranon fossa on the posterior side (where the olecranon process of the ulna fits in when the elbow is straightened). Both specimens are from the right side.

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