Musculoskeletal Ultrasound Technical Guidelines

Key points

• The guideline describes a systematic ultrasound examination of the elbow by quadrant; in practice, the examination usually focuses on one quadrant based on clinical findings.
• The distal biceps tendon is best examined on its long axis with the forearm in maximal supination, keeping the probe parallel to the tendon to avoid artifactual hypoechoic areas.
• The posterior interosseous nerve is followed on short-axis planes as it enters the arcade of Frohse, aided by forearm pronation and supination.
• Examining the joint at 45 degrees of flexion helps identify small effusions in the posterior olecranon recess.
• Dynamic imaging of the cubital tunnel during elbow flexion assesses ulnar nerve instability; firm probe pressure must be avoided.

Overview

This European Society of Musculoskeletal Radiology (ESSR) technical guideline sets out patient positioning and probe technique for ultrasound of the elbow, region by region. Its main message is that each structure has a preferred position and scanning plane, and that dynamic manoeuvres help reveal pathology that static images can miss.

Anterior elbow

The patient sits facing the examiner with the elbow extended and the forearm supinated; a pillow under the joint helps full extension. Transverse images are obtained by sweeping from about 5 cm above to 5 cm below the trochlea-ulna joint, showing the biceps and brachialis muscles, the brachial artery and the median nerve, which lies medial to the artery. Short-axis views are less useful for the distal biceps because small changes in probe angle alter tendon echogenicity. Sagittal planes show the coronoid fossa with the anterior fat pad, the humeral capitellum and trochlea, the radial head and the brachialis tendon down to the coronoid process. The radial nerve is followed between the brachioradialis and brachialis muscles to its division into the superficial sensory branch and the posterior interosseous nerve.

Lateral and medial elbow

The common extensor tendon is viewed on its long axis in coronal planes with the probe on the lateral epicondyle; normally the lateral ulnar collateral ligament cannot be separated from the overlying tendon. Dynamic pronation and supination help assess the radial head, exclude occult fractures and check the annular ligament. Medially, the common flexor tendon is shorter and larger than the extensor tendon, and the anterior bundle of the medial collateral ligament lies deep to it; this ligament is best examined with the patient supine, shoulder abducted and externally rotated and elbow flexed at 90 degrees, and valgus stress can show joint widening in partial tears.

Posterior elbow and cubital tunnel

With the elbow flexed at 90 degrees, the triceps muscle and tendon are examined on long and short axes, checking the distal tendon for enthesitis. Gentle rocking of the elbow can shift joint fluid into the olecranon recess, and excessive probe pressure should be avoided over the superficial olecranon bursa so small effusions are not squeezed away. The ulnar nerve is examined on short-axis views from the distal arm to the distal forearm, watching for shape changes across the epicondylar groove and cubital tunnel. During dynamic flexion, the positions of the ulnar nerve and the medial head of the triceps relative to the medial epicondyle are assessed; instability is related to absence of the Osborne retinaculum.

Frequently asked questions

Why is the distal biceps tendon examined on its long axis?

Because short-axis views are affected by small changes in probe orientation, which can alter tendon echogenicity and cause confusion with the adjacent artery.

How can small elbow effusions be detected?

By examining the joint at 45 degrees of flexion, when fluid tends to move into the posterior olecranon recess, and by gently rocking the elbow.

How is ulnar nerve instability assessed?

With dynamic transverse scanning between the olecranon and medial epicondyle during elbow flexion, avoiding firm probe pressure that could prevent the nerve from dislocating.

Source

Beggs I, Bianchi S, Bueno A, et al. Musculoskeletal Ultrasound Technical Guidelines. II. Elbow. European Society of Musculoskeletal Radiology (ESSR). This page is a summary prepared by Medpresso from the original publication and is not a substitute for the full text or for medical advice.