title: In vivo study of the surgical anatomy of the axilla.
abstract: BACKGROUND
  Classical anatomical descriptions fail to describe variants often observed in the axilla as they are based on studies that looked at individual structures in isolation or textbooks of cadaveric dissections. The presence of variant anatomy heightens the risk of iatrogenic injury. The aim of this study was to document the nature and frequency of these anatomical variations based on in vivo peroperative surgical observations.
  
  
  METHODS
  Detailed anatomical relationships were documented prospectively during consecutive axillary dissections. Relationships between the thoracodorsal pedicle, course of the lateral thoracic vein, presence of latissimus dorsi muscle slips, variations in axillary and angular vein anatomy, and origins and branching of the intercostobrachial nerve were recorded.
  
  
  RESULTS
  Among a total of 73 axillary dissections, 43 (59 per cent) revealed at least one anatomical variant. Most notable variants included aberrant courses of the thoracodorsal nerve in ten patients (14 per cent)--three variants; lateral thoracic vein in 12 patients (16 per cent)--four variants; bifid axillary veins in ten patients (14 per cent); latissimus dorsi muscle slips in four patients (5 per cent); and variants in intercostobrachial nerve origins and branching in 26 patients (36 per cent). The angular vein, a subscapular vein tributary, was found to be a constant axillary structure.
  
  
  CONCLUSIONS
  Variations in axillary anatomical structures are common. Poor understanding of these variants can affect the adequacy of oncological clearance, lead to vascular injury, compromise planned microvascular procedures and result in chronic pain or numbness from nerve injury. Surgeons should be aware of the common anatomical variants to facilitate efficient and safe axillary surgery.
authors.affiliation: Academic Surgery (Breast Unit), Royal Marsden NHS Foundation Trust, Fulham Road, London SW3 6JJ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: A
authors.initials: A
authors.lastname: Chakravorty
authors.forename: G P H
authors.initials: GP
authors.lastname: Gui
mesh_terms: D001365:Axilla / Q000033:anatomy & histology* / Q000098:blood supply / Q000294:innervation / Q000601:surgery*; D001367:Axillary Vein / Q000033:anatomy & histology / Q000601:surgery; D001917:Brachial Plexus / Q000033:anatomy & histology / Q000601:surgery; D004210:Dissection / Q000379:methods; D006801:Humans; D007367:Intercostal Nerves / Q000033:anatomy & histology / Q000601:surgery; D014680:Veins / Q000033:anatomy & histology / Q000601:surgery