Methods of ultrasound of the elbow joint

The structures that are subject to ultrasound evaluation in the elbow joint are: the joint cavity itself, articular cartilage, joint capsule; tendons of the muscles involved in the processes of flexion and extension of the joint; medial and lateral epicondyles, ulnar nerve. Ultrasound examination (US) of the elbow joint is performed from four standard approaches: anterior, medial, lateral and posterior. Two patient positions are used at the patient's discretion when examining the elbow joint: sitting or lying down.

Anterior approach. To examine the coronoid fossa area with the anterior approach, the arm is slightly flexed at the joint. To exclude possible partial ruptures and sprains of the tendons, it is necessary to compare with the data with full extension of the elbow joint. From the anteromedial approach, the distal part of the biceps tendon, the brachialis tendon, and the vessels of the coronoid fossa are assessed. Fibers of the deepest brachialis muscle are attached to the coronoid process of the ulna; above them follow the fibers of the biceps brachii muscle attached to the radial tuberosity. The brachioradialis muscle spans the entire length of the forearm: from the humerus above the supracondylar zone to the radius in the wrist area. During transverse scanning at the level of the coronoid fossa, the brachioradialis, biceps, brachialis, and pronator teres muscles are visualized as hypoechoic muscle structures around the humerus. In longitudinal scanning, these muscles are thrown over the elbow joint.

To assess the tendon-muscle junction and the tendon-bone attachment area, it is recommended to use the panoramic scanning mode. The median nerve runs between the pronator teres and the brachialis muscle. The radial nerve runs between the biceps brachii and the brachialis muscle.

Medial approach. For the medial approach, the arm should be abducted. The medial epicondyle, flexor tendons, and joint capsule are examined from the medial approach. The sensor is placed on the medial epicondyle - the direction of the sensor scan coincides with the course of the tendon fibers. This area is also examined in the transverse plane. The flexor muscle tendons are attached to the medial epicondyle.

Lateral approach. With the lateral approach, the arm is adducted. From this approach, the lateral epicondyle, extensor tendons, and joint capsule are assessed. The sensor is installed similarly to the elbow joint examination from the medial approach on the lateral epicondyle of the humerus. The tendons of the extensor muscles of the forearm, attached to the lateral epicondyle, are examined.

Posterior approach. To examine the posterior region, the dorsum of the wrist touches the iliac wing. From this position, the olecranon, triceps tendon, and olecranon bursa are assessed. The triceps tendon attaches to the proximal portion of the olecranon, forming a bursa at the attachment site. To examine the medial portion of the posterior surface of the elbow, the forearm is abducted laterally and rotated outward. The ulnar nerve passes between the medial epicondyle along the posterior surface and the olecranon process in the depression. On the forearm, the nerve lies deeper than the flexor digitorum ulnaris before entering Guyon's canal, projecting onto the skin surface along the edge of the hypothenar. On the forearm, the ulnar nerve follows a line connecting the medial epicondyle and the lateral aspect of the pisiform bone or hypothenar.

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