Unilateral Complete Congenital Serratus Anterior Muscle Aplasia: A Case Report

Abstract

A 28-year-old white man was referred to the authors’ outpatient clinic by his primary care physician for evaluation of presumed scoliosis. The patient reported decreased range of motion of the left shoulder with overhead activities and not being able to raise his left upper extremity as high as the right one throughout his life. He noted some upper back pain when exercising, specifically when performing abdominal crunches but not while performing activities of daily living. His medical history was significant only for chickenpox. He had never been hospitalized and his birth history was uncomplicated. His family history revealed colon cancer in a grandfather, and coronary artery disease and congestive heart failure in a grandmother. There were no known congenital disorders in the family. The patient’s occupation was a physician, he was a nonsmoker, and review of systems was unremarkable. The physical examination revealed the thorax to be slightly asymmetric with mild flattening of the left trunk contour and asymmetric position of the scapulae. The left scapula was noticeably smaller, elevated, and more medially positioned than the right. Anterior chestmusclesweresymmetricalwithoutatrophy.Theleftshoulderdemonstratedabnormal scapularrotationwithlimitedactiveflexionandabductionto120°.Medialscapularwinging and medial displacement of the inferior angle of the scapula occurred with left shoulder flexion.Therightupperextremitydemonstratedfull,normalrangeofmotion.Therewasno tenderness along the spine, trunk or scapula. Strength testing of the neck, shoulder girdle andupperextremitieswasnormalexceptfortheserratusanterior.Therestoftheneurologic examination was unremarkable.