1607 - Cutaneous Clues: Isolated Injury to the Lateral Antebrachial Cutaneous Nerve

Friday, February 20, 2026

5:00 PM - 6:30 PM AST

Corresponding Author(s)

MD

Miguel DeMarzo, III, DO

Resident Physician (PGY-1)
Baylor University Medical Center - Baylor Institute for Rehabilitation
Arlington, Texas, United States

Co-Author(s)

CS

Caitlyn E. Smith, MS

Medical Student
UNTHSC Texas College of Osteopathic Medicine
Fort Worth, Texas, United States
SN

Sharon Nguyen, BS

Medical Student
UNTHSC Texas College of Osteopathic Medicine
Fort Worth, Texas, United States

Presenting Author(s)

SC

Sean Canfield, BS

Medical Student (MS4)
TCU Burnett School of Medicine
Fort Worth, Texas, United States

Co-Author(s)

MB

Monica Botross, BS

Medical Student
TCU School of Medicine
North Richland Hills, Texas, United States
NK

Nimah Khan, n/a

Medical Student
Texas Tech Health Sciences Center El Paso
Plano, Texas, United States
OS

Omar Selod, DO

Physician
PMR Fort Worth
Fort Worth, Texas, United States

Submitter(s)

MD

Miguel DeMarzo, III, DO

Baylor University Medical Center - Baylor Institute for Rehabilitation
Arlington, Texas, United States

Case Diagnosis: Isolated Lateral Antebrachial Cutaneous Nerve Mononeuropathy

Case Description: A 57-year-old male presented with numbness in the left posterolateral antebrachial arm radiating for six months following a syncopal episode secondary to pneumonia. Imaging revealed a nasal fracture and a closed left humerus fracture. He was initially hospitalized and completed antibiotic treatment and discharged with conservative management of his humeral fracture with a splint and sling. Two months later, subsequently underwent open reduction and internal fixation (ORIF) of the humerus. A few months after surgery, the patient reported noticing his presenting symptoms which led to his electrodiagnostic (EDX) study which was notable for an isolated lateral antebrachial nerve (LACN) mononeuropathy on nerve conduction study (NCS).

Discussions: Musculocutaneous lesions as a whole comprise 1-2% of all upper extremity neuropathies. A retrospective analysis isolated 32 cases of musculocutaneous nerve injury in an 18 year time frame and found that LACN lesions only comprised 5 of those cases, emphasizing the importance of reporting cases of this rare subset. The suspected etiology given the time frame was believed to be a complication related to the surgical fixation. It was theorized that the patient's symptomatology is likely from reinnervation of the nerve lesion.

Conclusions: Given the rarity of isolated LACN lesions, a comprehensive clinical approach incorporating a detailed patient history, focused physical examination, and confirmatory electrodiagnostic studies was critical in obtaining an accurate diagnosis. Due to the low prevalence and variable clinical presentations associated with LACN neuropathy, case reports are valuable to enhance the understanding of suspected etiologies, clinical manifestations, and diagnostic strategies.