Real-World Evidence of Langer’s Axillary Arch: Bridging Anatomical Variations and Surgical Practice for Safer Axillary Procedures

Langer's axillary arch is an anatomical variant characterized by a fibromuscular band extending from the latissimus dorsi to the pectoralis major, humerus, or coracoid process, traversing the axillary region. This structure may alter expected anatomical relationships and has the potential to compress neurovascular elements, thereby complicating surgical procedures. Although extensively described in cadaveric studies, in vivo identification during surgery remains infrequently reported. Given its anatomical variability and potential impact on surgical outcomes, further intraoperative documentation of this variant is clinically relevant and may contribute to improved surgical safety and planning. We present the case of a 65-year-old female with left axillary lymph node metastases from melanoma, undergoing complete axillary lymphadenectomy. Intraoperatively, a fibromuscular structure consistent with Langer's axillary arch was identified, extending from the latissimus dorsi and crossing the neurovascular bundle before inserting on the humerus. Careful dissection was performed to preserve vital structures and ensure oncologic completeness. The lymphadenectomy was successfully completed with histologically clear margins. The patient tolerated surgery well, received adjuvant immunotherapy, and remains disease-free after one year of follow-up. The recognition of Langer's axillary arch during the procedure was critical in preventing inadvertent vascular or nerve injury, ensuring a safe and effective intervention. By bridging anatomical research with clinical practice, this case underscores the clinical importance of anatomy during surgical procedures in the axilla. Failure to recognize Langer's axillary arch can increase the risk of surgical complications, including neurovascular injury or incomplete dissections. The <i>in vivo</i> documentation of this structure provides a valuable educational reference for surgeons, emphasizing the relevance of detailed anatomical understanding in improving patient outcomes.