Triangle of auscultation

The triangle of auscultation of the lungs is a relative thinning of the musculature of the back, situated along the medial border of the scapula.
Boundaries.
It has the following boundaries:
The superficial floor of the triangle is formed by the lateral portion of the erector spinae muscles. Deep to these muscles are the osseous portions of the 6th and 7th ribs and the internal and external intercostal muscles.
Clinical Significance.
The triangle of auscultation is useful for assessment using a pulmonary auscultation and thoracic procedures. Due to the relative thinning of the musculature of the back in the triangle, the posterior thoracic wall is closer to the skin surface, making respiratory sounds audible more clearly with a stethoscope. On the left side, the cardiac orifice of the stomach lies deep to the triangle. In days before X-rays were discovered, the sound of swallowed liquids were auscultated over this triangle to confirm an oesophageal tumour.
Typically, the triangle of auscultation is covered by the scapula. To better expose the floor of the triangle up of the posterior thoracic wall in the 6th and 7th intercostal space, a patient is asked to fold their arms across their chest, laterally rotating the scapulae, while bending forward at the trunk, somewhat resembling the fetal position.
The triangle of auscultation can be used as a surgical approach path. It can also be used for a nerve block known as the rhomboid intercostal nerve block, which can be used to relieve pain after rib fractures.