The Humerus
The humerus is a long bone in the upper arm that runs from the shoulder to the elbow. The top of the humerus fits into a cavity in the scapula (shoulder blade), creating a ball and socket joint (the shoulder joint) which allows a wide range of movement.At its bottom end it fits inside the top of the ulna and radius, to form a hinge joint at the elbow. Hinge joints are the simplest type of joint; they allow movement in only one direction. Muscles attached to the humerus allow it to rotate and to move, and to move the forearm below it. The humerus isn't actually your 'funny bone', despite its name. That's actually the ulnar nerve, which passes under the end knob of the humerus at the elbow and is vulnerable to pressure. |