Disclosures: Hans L. Carlson, MD: No financial relationships or conflicts of interest

Case Description: The patient presented with a 6 month history of bilateral mid-biceps achiness and weakness after changing his weightlifting to include biceps curls combined with an overhead lift (Arnold press). He did not report any functional weakness except when lifting heavier weights. He stated that the discomfort was associated with intermittent bilateral upper extremity paresthesia and reports additional discomfort at the posterior elbow and shoulder. He had a prior similar episode approximately 1.5 years earlier that resolved with activity modification. He had normal strength, sensation, and reflexes with normal cervical range of motion and negative Spurling’s maneuver. His shoulder examination was unremarkable. EMG detected increased insertional activity in the biceps, bilaterally. MRI of the cervical spine demonstrated moderate-severe neuroforaminal narrowing. The patient improved with a modified weightlifting regimen.

Setting: Tertiary referral center

Patient: A 43-year-old male with bilateral biceps weakness Assessment/

Results: This patient had a bilateral musculocutaneous nerve injury potentially with repetitive loaded shoulder and elbow flexion with correlating electrodiagnostic findings.

Discussion: Isolated musculocutaneous nerve injuries associated with strenuous elbow flexion are uncommonly reported. Of the eight prior case reports, the majority describe unilateral injuries with resolution of symptoms and findings after 3-4 months of activity modification/rest. This case is unique with bilateral biceps weakness with musculocutaneous nerve injuries connected with repetitive shoulder and elbow flexion while weightlifting. The anatomic course of the musculocutaneous nerve may predispose individuals to entrapment at the coracobrachialis. This diagnosis should be considered in patients with history of strenuous elbow flexion, particularly when combined with shoulder flexion.

Conclusion: The repetitive combination of shoulder and elbow flexion resistance training may be a risk factor for injury to the musculocutaneous nerve at the coracobrachialis.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/atraumatic-elbow-flexion-weakness-in-the-setting-of-intensive-biceps-upper-extremity-weightlifting-a-mechanism-for-musculocutaneous-nerve-injury-at-the-coracobrachialis-a-case-report/