53 - Triangle of Auscultation

*The triangle of ausculation of the lungs is situated posterior and superficial to the scapula.

*It has the following boundaries:
- Superiorly, by the Trapezius
- Inferiorly, by the Latissimus dorsi
- Laterally by the medial margin of the scapula

*The floor is partly formed by the Rhomboideus major and parts of 6th and 7th ribs.

*The triangle of auscultation is a space on the back where the relatively thin musculature allows for respiratory sounds to be heard more clearly with a stethoscope.
*To better expose the floor of the triangle, which is made up of the posterior thoracic wall in the 6th intercostal space, the patient is asked to fold their arms across their chest, medially rotating the scapulae, while bending forward at the trunk.

52 - Coronary arteries and Coronary veins

*The coronary arteries and the veins that drain into the coronary sinus. The posterior interventricular branch (PIV), although usually a branch of the right coronary artery (RC), may arise from the circumflex branch (C) of the left coronary artery (inset). In B, the left marginal vein can be seen ascending to join the great cardiac vein. The posterior vein of the left ventricle ascends and the oblique vein of the left atrium descends to end in the coronary sinus.

*AIV, anterior interventricular branch; C, circumflex branch; GC, great cardiac vein; LC, left coronary artery; MC, middle cardiac vein; PIV, posterior interventricular branch; Re, right coronary artery; S.-A, branch to sinuatrial node; SC, small cardiac vein.