Nareka A. Trewick, MD
Resident Physician
University of Miami/Jackson Memorial Hospital
Miami, Florida, United States
Kerven Cassion, BS
Medical Student
University of Miami Miller School of Mediicne
Miami, Florida, United States
Griffin Harris, BS
Medical Student
University of Miami Miller School of Medicine
Miami, Florida, United States
Jean Jose, DO
Professor
University of Miami Miller School of Medicine
Miami, Florida, United States
Andrew L. Sherman, MD
Professor
University of Miami Miller School of Medicine
Miami, Florida, United States
Musculocutaneous nerve injury is a rare occurrence that can result in significant functional impairment and pain for patients. This case highlights the importance of proper clinical evaluation and diagnostic testing in identifying musculocutaneous nerve injuries to inform appropriate treatment and management strategies. A 24-year-old male baseball pitcher with no past medical history presented with several weeks of moderate pain, tingling, and numbness in the right forearm and upper arm as well as weakness in his biceps during elbow flexion. This pain occurred suddenly and was constant after the original insult. The patient underwent NCS/EMG test, ultrasound, and MRI of the extremity to confirm the diagnosis. He was treated with a corticosteroid injection and advised to temporarily avoid pitching with subsequent significant relief of symptoms.
Discussions:
The musculocutaneous nerve pierces the coracobrachialis muscle as it continues its course distally. Given the repetitive overhead motion that pitchers' arms undergo, this patient may have experienced abrupt trauma to this area while pitching. This condition may be overlooked, as more common pathologies such as biceps brachii strains or tendinopathies present similarly. Therefore, without proper workup with imaging and nerve conduction studies, differentiating between these pathologies can be challenging. Musculocutaneous nerve injuries should be considered in the differential when a patient presents with elbow flexion weakness and sensory deficits in forearm distribution. This is particularly relevant for baseball pitchers, as the biomechanics of pitching makes them especially susceptible to this specific pattern of nerve injury.
Conclusions:
This study reports a rare case of musculocutaneous nerve injury due to compression via the coracobrachialis muscle. The comprehensive workup, including imaging and EMG, underscores the importance of considering this diagnosis in similar clinical scenarios, providing valuable insights for future practitioners.
