Humerus
The humerus is the bone of the upper arm. The smooth, dome-shaped head
of the bone lies at an angle to the shaft and fits into a shallow socket
of the scapula (shoulder blade) to form the shoulder joint. Below the
head, the bone narrows to form a cylindrical shaft. It flattens and
widens at the lower end and, at its base, it joins with the bones of the
lower arm (the ulna and radius) to make up the elbow.
Some people say the "funny bone" is named because it is next to the
humerus. It really isn't a bone at all, but is the ulnar nerve, which
passes under a prominence of the humerus, where it is vulnerable. To find
the funny bone, put the point of the right elbow on a table. Above and to
the left of the point is a big knob. When it is struck, the blow pushes
the nerve against this knob, causing temporary paralysis. It is no
laughing matter, but it is a "funny" feeling.
