Paresthesias on the lateral face of the forearm: A nervous injury that is difficult to recognize

The lateral antebrachial cutaneous nerve (LACN) is the sensory branch of the musculocutaneous nerve and usually innervates the lateral aspect of the forearm. Isolated lesions are rare, of varied etiology and generally underdiagnosed. We present a retrospective descriptive study of electromyography performed at the General University Hospital of Castellón in the last 20 years with isolated NCAL lesion. We identified 11 cases (8 men and 3 women), average age 44 years (15-73 years). 73% were referred from traumatology. Only one patient was correctly guided in the application. 63.6% of cases noted hypoesthesia extending to the wrist and 18.2% to the thumb. The electromyographic study showed severe axonal involvement in 3 patients and moderate in 8. The symptoms were observed associated with surgery in 4 patients, manipulation of the elbow flexure in 4 cases and bicipital tendonitis in the rest. Four patients had a poor clinical outcome (3 with severe axonal involvement and 1 with moderate involvement). Isolated involvement of the NCAL is a rare and underdiagnosed alteration. It is important to suspect it in patients with hypoesthesia in the forearm, including the radial edge of the wrist or thumb, especially if it is associated with manipulations around the elbow flexure or bicipital tendonitis. Electromyography is useful in confirming the diagnosis, ruling out other differential diagnoses, and predicting prognosis. Knowing the location of this nerve during manipulations on the arm and placing patients in an appropriate posture during surgeries can help minimize cases.