Antecubital Fossa Definition
The antecubital fossa, or simply elbow pit, is the small triangular depression in the arm which is formed by the connection of the humerus with the radius and ulna of the forearm. A fossa, in anatomical terms, is from the Latin word meaning small ditch or groove. The numerous muscles and tendons that surround the muscles, as well as the synovial joint formed between the bones of the arm create the antecubital fossa.
Specifically, the antecubital fossa exists in the triangular region created by end of the humerus and two muscles that create a triangle as they attach from the humerus to the wrist. These muscles are the brachioradialis and the pronator teres muscles. The brachioradialis is highlighted in the following image. The antecubital fossa is bounded on the top by the skin and several veins and nerves, while it is bounded on the bottom by more muscles.
The antecubital fossa houses several important structures. The radial nerve passes on the same side of the arm as the radius. The radial nerve supplies many of the muscles of the arm. The median nerve also passes through the antecubital fossa, and continues on to innervate much of the hand. Part of the structure that forms the antecubital fossa is the biceps brachii tendon, which connects the biceps to bone. Lastly, the brachial artery supplies blood to much of the arm, and often divides in the antecubital fossa to become the radial and ulnar arteries. The antecubital fossa can be approximated from these structures in the following image.