Winged scapula after carrying weight under the armpit: Ultrasonographic examination of the distal long thoracic nerve and serratus anterior muscle.

Abstract

The most common etiologic cause of winged scapula (WS) is paralysis of the serratus anterior muscle (SAM), typically due to an injury of the long thoracic nerve (LTN), often associated with overhead activities, including heavy weightlifting. Herein, we reported a 30-year-old male patient with WS secondary to an LTN lesion caused by carrying weight under the armpit, rather than overhead, which differs from previous reports regarding the anatomical site and cause of the LTN lesion. The ultrasonographic technique used to evaluate distal lesions of the LTN was described in detail, with the SAM thickness significantly reduced and the cross-sectional area of the LTN increased on the symptomatic side. Electroneuromyography revealed an acute/subacute, mild partial axonal lesion of the LTN, with ultrasonographic evaluation pinpointing the exact anatomical location of the lesion. Ultrasonography should be the first imaging modality used to support electrophysiological studies and evaluate the affected nerves and muscles to reveal precise anatomical localization.