What anatomical feature is primarily used to locate the ulnar artery?

The primary anatomical feature used to locate the ulnar artery is the flexor carpi ulnaris muscle. This muscle is positioned on the medial side of the forearm and runs along the ulnar side, making it a key landmark for identifying the ulnar artery as it travels beneath and alongside this muscle.

In practical terms, when locating the ulnar artery for procedures such as arterial access or during cadaveric studies, practitioners can palpate the flexor carpi ulnaris to help orient themselves. Understanding the relationship between anatomical structures is crucial in clinical settings where accurate identification of arteries is necessary for both diagnostic and therapeutic interventions.

Other choices such as the flexor carpi radialis, adductor longus, and sartorius muscles do not have the same anatomical proximity or relevance to the ulnar artery, thereby making them less appropriate for locating this specific blood vessel. The flexor carpi radialis, for instance, is associated with the radial side, while the adductor longus is primarily involved in leg movement and is located in the thigh, and the sartorius muscle spans the thigh and leg area with no direct relationship to the ulnar artery.