The elbow joint, a complex structure connecting the upper arm to the forearm, plays a central role in daily movements like bending, straightening, and rotating the arm. It is formed by the humerus, radius, and ulna bones, supported by various muscles, ligaments, nerves, and blood vessels. While the outer elbow is widely recognized, the inner elbow has a specific anatomical designation and performs essential functions for hand and arm movement.
Anatomical Name and Location
The inner elbow is medically known as the cubital fossa, or antecubital fossa, referring to its position anterior to the elbow joint. This triangular-shaped depression serves as a transitional area between the upper arm and the forearm.
The superior border of the cubital fossa is an imaginary horizontal line connecting the medial and lateral epicondyles of the humerus, which are bony prominences on either side of the lower upper arm bone. Its medial boundary is formed by the lateral edge of the pronator teres muscle, a muscle involved in forearm rotation. Conversely, the lateral boundary is created by the medial edge of the brachioradialis muscle, which assists in elbow flexion. The apex of this triangular area points downwards, where these two muscles converge.
Key Structures and Their Significance
Within the cubital fossa lie several important anatomical structures that pass between the upper arm and forearm. One such structure is the brachial artery, the main blood vessel supplying blood to the arm and hand. It travels medial to the biceps tendon within the fossa and divides into the radial and ulnar arteries at the cubital fossa’s lower end, providing blood flow to the lower arm. The median nerve also passes through this region, located medial to the brachial artery. This nerve controls most of the muscles that flex the wrist and fingers, and provides sensation to parts of the forearm and hand.
The median cubital vein is a prominent superficial vein in the cubital fossa. This vein connects the cephalic vein on the outer arm to the basilic vein on the inner arm, facilitating blood return. Its stable location and size make it a common site for drawing blood (venipuncture) and inserting intravenous lines. The biceps tendon, which attaches the biceps muscle to the radius bone, also runs centrally through the cubital fossa, contributing to elbow movement.
Common Conditions Affecting the Inner Elbow
The inner elbow region is susceptible to several medical conditions and injuries due to its complex anatomy and the structures passing through it. One common ailment is Golfer’s Elbow, medically termed medial epicondylitis, which causes pain and inflammation in the tendons attaching forearm muscles to the bony prominence on the inside of the elbow. This condition results from repetitive wrist and arm motions, such as those involved in sports like golf or certain occupations. The pain extends along the inner forearm and may be accompanied by stiffness or weakness.
Cubital Tunnel Syndrome involves the compression or irritation of the ulnar nerve as it passes through the cubital tunnel, a narrow passageway on the inner side of the elbow. This nerve, often referred to as the “funny bone,” controls sensation in the ring and little fingers and some hand muscles. Symptoms include numbness, tingling, and pain in these fingers and sometimes radiating pain from the elbow down to the hand or up to the shoulder. Prolonged elbow bending or leaning on the elbow can contribute to this condition.