The long thoracic nerve: Possible mechanisms of injury based on autopsy study

Forty dissections in 21 adult cadavers were analyzed to determine whether the long thoracic nerve could be mechanically damaged or its blood supply threatened along its peripheral course. The mean length of the nerve was 21.9 cm measured from the upper border of the serratus anterior; it ended an average of 8.4 cm distal to the inferior angle of the scapula. Three postmortem arteriographs were done, and the blood supply to the lower part of the nerve was observed radiographically and in the dissections. The nerve and its blood supply were found to be vulnerable for both compression and stretching anterior to the lower part of the scapula. The findings differ from previous theory about nerve injury at the level of the second rib. Marked interindividual differences in the course of the nerve were noted; this may explain why some people experience paralysis while others do not.