Back and 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