Back & Spinal Cord LO 2

2. Identify the latissimus dorsi muscle. Understand the muscle’s attachments, functions, innervation, blood supply, anatomical relationships, and clinical considerations.

Latissimus dorsi m.

  • Proximal attachments:
    • T7-T12 spinous processes
    • Thoracolumbar aponeurosis (fascia),
    • Iliac crest,
    • Ribs 9-12
  • Distal attachment:
    • Floor of the intertubercular sulcus (bicipital groove) of the humerus
  • Action(s):
    • Medial rotation of shoulder (glenohumeral) joint;
    • Extension of shoulder joint;
    • Adduction of shoulder joint
  • Innervation:
    • Thoracodorsal n. [posterior cord of brachial plexus: C6-C8]
  • Dominant arterial supply:
    • Thoracodorsal a. [continuation of subscapular a.]
  • Anatomical relationships:
    • The widest (latissimus) muscle of the back (dorsi)
    • Forms the inferior border of the triangle of auscultation
    • Forms the medial border of the lumbar triangle