Serratus Anterior Muscle Injury Presenting as Chest Pain: A Case Report

Case Diagnosis: A 67-year-old man with hypertension, hyperlipidemia, lumbar spinal stenosis, thoracic degenerative disc disease, and right glenohumeral arthritis presents with right-sided chest pain.

Case Description or Program Description: The patient presented to the emergency department with severe right anterior chest pain radiating from the mid-back, which he described as aching and throbbing. He denied any trauma, numbness, or shooting sensations, and the pain worsened at night and with shoulder movement. He had no shortness of breath, palpitations, chest pressure, or diaphoresis. Examination revealed normal vitals and breath sounds, with no muscle atrophy or trigger points in the cervical and thoracic regions. However, moderate tenderness was noted along the right fifth to ninth ribs, worse with scapular protraction.

Setting: Urban Veteran Affairs Healthcare System

Assessment/Results: Chest x-rays and routine labs were normal. A thoracic MRI revealed multilevel disc herniations and neuroforaminal stenosis, while a right shoulder x-ray showed osteoarthritis. Based on reproducible local pain with palpation and muscle stretching, the patient was diagnosed with a serratus anterior (SA) muscle strain.

Discussion (relevance): Differential diagnoses included thoracic radiculopathy, costochondritis, and pulmonary or cardiac causes. Although the patient had neuroforaminal stenosis, the absence of neurological deficits made radiculopathy less likely. Costochondritis was unlikely due to the lack of pain on palpation. Cardiac and pulmonary etiologies were deemed less likely due to the right-sided pain and absence of respiratory symptoms, respectively. The patient was treated with ibuprofen, a lidocaine 1% patch, daily icing and stretching exercises. He reported significant improvement within 1-2 weeks.

Conclusions: Serratus anterior muscle strain can mimic chest pain and may be mistaken for pulmonary or cardiac conditions. Clinicians should consider SA strain in the differential diagnosis of chest pain.