Latissimus Dorsi

• Latissimus Dorsi

  • Large, flat, triangular muscle on the posterior aspect of the trunk
  • Fibres pass upwards and laterally and twist on themselves to form a tendon for the proximal attachment

  
• O (origin)

  • Spinous processes of the lower 6 thoracic vertebrae and all the lumbar and sacral vertebrae (via thoracolumbar fascia)
  • Intervening supraspinous and interspinous ligaments
  • Outer lip of the posterior part of the iliac crest

  A) Latissimus Dorsi

  
• R (direction)

  • Upwards and laterally

  A) Latissimus Dorsi

  
• I (insertion)

  • En-route, some fibres attach to the outer surfaces of the lower 3 or 4 ribs and the inferior angle of the scapula
  • Floor of the intertubercular groove via thin flattened tendon, anterior to the teres major tendon

  A) Latissimus Dorsi

  
• A (actions)

  • Extensor of flexed arm, adductor and medial rotator of the glenohumeral joint

  A) Latissimus Dorsi

  
• NS (nerve supply)

  • Thoracodorsal nerve (C6 - C8)

  A) Latissimus Dorsi

  
• O (origin)

  • Outer lip of the posterior part of the iliac crest
  • Intervening supraspinous and interspinous ligaments
  • Spinous processes of the lower 6 thoracic vertebrae and all the lumbar and sacral vertebrae (via thoracolumbar fascia)

  A) Latissimus Dorsi

  
• I (insertion)

  • Floor of the intertubercular groove via thin flattened tendon, anterior to the teres major tendon
  • En-route, some fibres attach to the outer surfaces of the lower 3 or 4 ribs and the inferior angle of the scapula

  A) Latissimus Dorsi