A cadaveric study for the volar needle approach to the pronator quadratus using the palmaris longus tendon landmark

Introduction: Our aim in this work was to determine the safety and accuracy of the volar approach to the pronator quadratus (PQ) through cadaver dissection. Methods: Twenty upper limbs from 10 fresh cadavers were investigated. At the level 3 cm proximal to the ulnar styloid process (USP), a needle was inserted just medial to the palmaris longus (PL) tendon. Distances of the median nerve (MN) and ulnar artery (UA) from the needle insertion point (IP) were measured using ultrasonography and cadaver dissection. Results: The PQ was located at a depth of 10.8-19.9 mm from the skin and had a median thickness of 9.1 mm, measured 3 cm proximal to the USP. The median distances of the MN and UA from the IP were 7.6 and 13.4 mm, respectively. Discussion: A needle insertion for the volar approach to the PQ was safe at 3 cm proximal to the USP, just medial to the PL tendon.