Pavel Novotny

In anatomy, an arm is one of the upper limbs of an animal. The term arm can also be used for analogous structures, such as one of the paired upper limbs of a four-legged animal, or the arms of cephalopods. In the lexicon of human anatomy, the term arm refers specifically to the segment between the shoulder and the elbow. The segment between the elbow and wrist is the forearm. However, in colloquial speech the term arm often refers to the entire upper limb from shoulder to wrist.

In primates the arms are richly adapted for both climbing and for more skilled, manipulative tasks. The ball and socket shoulder joint allows for movement of the arms in a wide circular plane, while the presence of two forearm bones which can rotate around each other allows for additional range of motion at this level.