Which vessel courses along the medial aspect of the Psoas muscle?

The external iliac artery is the vessel that courses along the medial aspect of the psoas muscle. As it travels down from the abdominal aorta, the external iliac artery runs along the psoas muscle before it continues into the lower limb. Understanding the anatomy of vascular structures is crucial, as the external iliac artery plays a significant role in supplying blood to the lower extremities.

The renal artery branches off the abdominal aorta and typically travels laterally to supply the kidneys, making it less relevant in this context. The common femoral artery is a continuation of the external iliac artery but is situated more lateral as it enters the thigh. The inferior mesenteric artery arises from the abdominal aorta and supplies the distal colon, but it does not follow the course of the psoas muscle. Therefore, identifying the external iliac artery as the correct answer highlights its anatomical relationship with the psoas, which is essential for both surgical and diagnostic procedures.