The connection point where the lower segment of the arm links to the upper segment creates a wedge-shaped or triangular hollow referred to as the cubital fossa. This area — located on the anterior or front side of the arm — contains several key components responsible for allowing the whole arm to move as a complete unit. This area also permits the lower section of the arm from the elbow to the hand to function independently from the rest of the arm.
Inside the space of the cubital fossa, the radius and ulna, the two lower arm bones, connect to the humerus or upper arm bone. These bones form a joint held together by a series of ligaments, flexible yet sturdy bands of tissue, as well as several muscles whose tendons stretch across space to attach to both the upper and lower arm bones. Also located within the cubital fossa are essential nerves and blood vessels responsible for supplying the lower arm, wrist and hand with necessary nutrients such as blood and oxygen, and a communication system for appropriate movements and sensations.
Included in the important structures within the cubital fossa is the radial nerve. This cord-like collection of fibers is the pathway for information such as sensory and motor impulses to be passed to and from the brain and throughout the entire arm. This then creates specific and precise arm movements, which allow for the brain to interpret pain signals if the arm sustains an injury. For example, if the radial nerve becomes impinged or squeezed, signals are passed through the fibers to the brain. The brain then interprets the injury and alerts the body of the problem by creating the sensation of pain occurring in the area that is damaged.
The median nerve is another important nerve located within this space. Extending from the shoulder area down through the arm, this nerve runs to the forearm together with a main blood vessel called the brachial artery, also located inside the cubital fossa. This thin, tube-like channel runs from the shoulder to the lower or interior section of the cubital fossa where it splits and branches out into two separate vessels, the radial and ulnar arteries. In turn, these arteries supply the lower arm with a pathway to receive fresh oxygenated blood, the radial artery lying superficially or closer to the surface and providing for the lateral section of the forearm, and the ulnar artery sitting deeper and delivering blood to the middle or medial aspect of the forearm.