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Anterior Elbow

This is a superficial view of a right upper extremity elbow joint. Important structures to note include the biceps brachii and brachioradialis muscles, also the wrist and finger flexors which originate from the medial epicondyle of the humerus are prominently seen. The bicipital aponeurosis is a medial expansion of the biceps brachii tendon. It blends with the fascia covering the anterior forearm and can be hard to specifically identify. It is especially important to review the other structures (nerves and arteries) that cross the elbow. On your cadaver, note the anatomical relationship of each muscle to another as well as the course different nerves and arteries run as they traverse from the shoulder (proximal) to the hand (distal).

For a closer look at the anterior elbow structures named above, click to zoom in. The cubital fossa is identified in this picture. Review the relationship of the biceps brachii tendon to the brachial artery and median nerve as they all pass through this area.

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Posterior Elbow

A superficial look at the posterior side of the elbow does not reveal many structures. The triceps brachii muscle encompasses all of the posterior surface of the humerus. The lateral epicondyle serves as the proximal attachment for the wrist and finger extensors. The muscle bellies and tendons of these muscles run from their common origin, down the posterior forearm to the dorsal hand and wrist where they have their respective distal attachments. An easily palpable landmark at the posterior elbow is the large bony mass at the proximal end of the ulna called the olecranon process.

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Radial (Lateral) Collateral Ligament

The radial (lateral) collateral ligament is an important lateral stabilizer of the elbow joint. Varus (medial) stresses are opposed by this ligament. It is triangular in shape and attaches proximally to the lateral epicondyle of the humerus, the distal fibers blend with the annular ligament which surrounds the head of the radius. The annular ligament can become injured in children when a large, quick traction force is applied to the joint, like when lifting a child by the hand. The radial head is pulled distally out of the annular ligament, tearing some of the fibers.

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Ulnar (Medial) Collateral Ligament

The ulnar (medial) collateral ligament is a broad fibrous band that runs from the medial epicondyle to the coronoid and olecranon processes of the ulna. This ligament is composed of three parts: anterior, posterior and oblique. It provides protection against valgus (lateral) stresses to the elbow. Recently it has become more well known in the public as the ligament that is injured in throwing sports, especially among pitchers in baseball.

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Elbow Joint Capsule

Like all synovial joints in the body, the elbow joint is surrounded by a bag-like joint capsule. It attaches proximally to the coronoid and radial fossae on the anterior surface of the humerus, on the posterior surface of the humerus it attaches just inferior to the olecranon fossa. At its distal extent, the fibrous capsule blends with the annular ligament as well as the trochelar notch and coronoid process of the ulna.

This image provides another view of the joint capsule. Although suttle in this picture, notice how the radius rolls medially over the ulna when pronated. Consider the support that the annular ligament provides when this movement occurs.

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Elbow Joint

The elbow joint is a fairly stable joint of the upper extremity due to the close relationship between the trochlea of the humerus and the trochlear notch of the ulna. The stability is heightened by the radial collateral and ulnar collateral ligaments. This joint is actually composed of three joints: the humeroulnar articulation between the trochlea of the humerus and trochlear notch of the ulna, which allows flexion and extension; the humeroradial articulation between the capitulum of the humerus and the head of the radius, which allows gliding to occur between these two bones during movements; and the proximal radioulnar joint between the head of the radius and the radial notch of the ulna, which permits rotation of the radius on the ulna during forearm supination and pronation.

For a closer look at the structures described above, click to zoom in. Along with giving a view of the important ligaments around the elbow joint, observe the coronoid fossa which is formed on the humerus as a result of interaction with the coronoid process of the ulna during elbow flexion. This image also demonstrates the relationship between the articular surfaces described above, like the trochlea and the capitulum.

Annular Lig.

Biceps Brachii M.

Bicipital Aponeurosis

Brachioradialis M.

Capitulum

Coronoid Fossa

Coronoid Process

Cubital Fossa

Elbow Joint

Elbow Joint Capsule

Lateral Epicondyle

Medial Epicondyle

Olecranon Process

Radial (Lateral) Collateral Lig.

Radial Fossa

Radial Head

Triceps Brachii M.

Trochlea

Ulnar (Medial) Collateral Lig.

Wrist/Finger Extensor MM.

Wrist/Finger Flexor MM.