Axillopectoral muscle: An important anomaly in axillary surgery

The axillopectoral muscle (Langer's axillary arch) is a common, though rarely noted, anatomical anomaly causing a range of rare clinical syndromes. Knowledge of the anomaly is increasingly important in the era of minimal access surgery and sentinel lymph node biopsy (SLNB) where it might produce false negative biopsies. We describe a case and review the current literature regarding its morphology. The axillopectoral muscle is found in 6% of human subjects, typically as a musculotendinous band 7–15 cm in length running between latissimus dorsi and pectoralis major with considerable morphological variation. It has been attributed to 2/15 false negative SLNB in one series. The axillopectoral muscle is common, variable and increasingly important in the era of SLNB.