Before drawing an arterial blood gas sample, a junior doctor palpates the radial artery at the wrist. Relative to the tendons at the wrist crease, the radial artery lies in which position?

• A Medial to the tendon of flexor carpi ulnaris
• B Just lateral to the tendon of flexor carpi radialis ✓
• C Between the tendons of palmaris longus and flexor carpi radialis
• D Deep to the tendon of extensor pollicis longus

Explanation

At the wrist the radial artery lies immediately lateral to the tendon of flexor carpi radialis, between that tendon and the lateral wall of the carpal tunnel, which is why the artery is palpated just radial to this tendon for cannulation and blood gas sampling. Medial to flexor carpi radialis lie the median nerve, palmaris longus and the ulnar neurovascular bundle, so a needle placed between the flexor tendons risks median nerve injury rather than reaching the artery.

Reference: Last's Anatomy: Regional and Applied, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.