Back and Spinal Cord - LO 3

3. Describe the borders and clinical significances of the triangle of auscultation and the inferior lumbar triangle. 

Triangle of auscultation: The triangle of auscultation is a region of the posterior thorax devoid of superficial back muscles, which allows for optimal auscultating lung sounds. Borders include:

• Laterally: Medial border of the scapula (border of rhomboid major m.),

• Medially: Ascending fibers of the trapezius m., &

• Inferiorly: Superior border of the latissimus dorsi m. 

Inferior lumbar (Petit’s) triangle: The inferior lumbar triangle is a region of the lower back devoid of superficial back muscles, which is mildly susceptible to herniation (protrusion of tissue or organs). Inferior lumbar hernias are very uncommon. Borders include:

• Laterally: External oblique m.,

• Medially: Latissimus dorsi m., &

• Inferiorly: Iliac crest.