An Intraoperative Encounter With Langer's Axillary Arch and Its Clinical Significance.

Langer's axillary arch (LAA) is the most common accessory muscle encountered during axillary surgery. We present a 55-year-old lady who underwent a right wide local excision and sentinel lymph node biopsy. Intraoperatively, we identified an aberrant muscle slip traversing the axilla, anterior to the neurovascular structures. It originated from the latissimus dorsi muscle and inserted into the pectoralis major. This report explores the current knowledge of LAA and discusses the importance of recognising it intraoperatively in the era of minimisation of axillary surgery. Implications of failing to recognise it include suboptimal regional control, compromised oncological treatment, or neurovascular injuries.