The snapping medial antebrachial cutaneous nerve

Abstract

Snapping elbow is a well-known condition where elbow flexion and extension elicits a painful, popping sensation. The most frequent etiology is anterior dislocation of the ulnar nerve over the medial epicondyle. Four patients (3 females and 1 male) presented with complaints of a popping sensation in the elbow, pain over the medial aspect of the forearm, and ulnar neuritis. All patients underwent preoperative dynamic ultrasound and surgical exploration of the medial elbow. Intraoperatively, snapping of the MABC over the medial epicondyle was discovered in all four patients. In three patients, there was abnormal displacement of the medial triceps and ulnar nerve: in two of these, both structures dislocated over the medial epicondyle and in one patient both structures subluxated. In each case, the MABC was decompressed (n = 1) and transposed (n = 3), and in three cases, the medial triceps and ulnar nerve were addressed as well. Symptomatic improvement was achieved in all cases. Retrospective review of the ultrasound revealed the snapping MABC, though it was less effective prospectively in the cases when snapping MABC was not suspected. In conclusion, snapping of the MABC broadens the spectrum of disorders that results in snapping elbow. To our knowledge, we are unaware of prior reports of this entity.

The Italian master Leonardo da Vinci and his early understanding of the brachial plexus

“…The brachial plexus continues to be of significant clinical interest [8][9][10][11][12][13] and thus our current knowledge of this structure was begun by the works of da Vinci in the fifteenth century. …”

The Sonographic Posterolateral Rotatory Stress Test for Elbow Instability: A Cadaveric Validation Study

“…US provides high‐resolution imaging of elbow tendons, nerves, ligaments, and accessible joint recesses. Furthermore, US can dynamically assess tendon motion, nerve instability or snapping, and joint laxity [9‐16]. Although previous research has documented the ability to sonographically identify the LCLC, assessment of lateral side laxity/instability has been limited to nonquantified and nonvalidated descriptions of sonographic varus stress testing [13‐15].…”

“…Ultrasound (US) provides a unique combination of high‐resolution, soft‐tissue imaging, dynamic capabilities, portability, lack of radiation exposure, immediacy of results, reduced costs compared with other modalities, and lack of contraindications [9], In recent years, the role of musculoskeletal (MSK) US in sports and MSK medicine has continued to expand. Multiple studies have documented the ability of MSK US to image the soft tissue and bony structures about the lateral elbow, as well as assist in the diagnosis and management of lateral elbow disorders affecting the common extensor tendon, radiocapitellar joint, and posterior interosseous nerve [10‐12].…”

Medial elbow pain

“…Other causes of snapping and medial elbow pain must be excluded clinically and include ME, posterolateral rotatory instability, isolated ulnar nerve dysfunction, MCL injury, synovial folds, loose bodies, failed ulnar nerve surgery after transposition, anconeous oedema and snapping of the medial antebrachialis cutaneous nerve. 5 , 42…”

“…The medial antebrachial cutaneous nerve (MABCN) has also been reported to be a cause of medial elbow pain. 5 Other diagnoses that may produce medial elbow pain are ulno-humeral arthritis, the presence of medial osteophytes, medial epicondyle avulsion fractures or the rare presence of osteochondritis dissecans of the trochlea.…”