A 37-year-old woman presents 2 weeks following a self-inflicted laceration to the wrist. She was involuntarily committed to a psychiatric hospital after the injury and presents to the office just after discharge. The wound was cleaned and sutured by a provider in the emergency department 2 weeks ago. She states that the emergency department provider mentioned she may have had a tendon injury and requested that she follow-up for an orthopedic consultation. On physical examination, there is a well-healed, 4-cm laceration running medial to lateral across the distal forearm. The patient admits the separate laceration running proximal to distal on the ulna border of the forearm was superficial and did not require suture closure. The patient is able to flex the distal interphalangeal joint and the proximal interphalangeal joints in all digits. Wrist flexion, ulnar deviation, and radial deviation are intact. Light touch sensation throughout the wrist and hand is intact. Allen’s test is unremarkable.
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The most superficial tendon at the wrist level is the palmaris longus tendon and the most likely tendon to be injured in this patient. The palmaris longus is absent in 10% to 15% of people but can be identified as the prominent tendon when the wrist is flexed and the fist is clenched.
The palmaris longus tendon is a wrist flexor but complete laceration may not cause any noticeable weakness. For this reason, the palmaris longus is the most common tendon graft used in the hand. The most common procedure that utilizes a palmaris graft is a ligament reconstruction and tendon interposition (LRTI) for carpometacarpal (CMC) arthritis.
The remaining flexor tendons of the wrist are listed from superficial to deep: flexor carpi radialis on the thumb side of the wrist (flexes and radial deviates the wrist); flexor digitorum superficialis coursing midline (flexes the proximal interphalangeal joints); flexor carpi ulnaris on the pinky side of the wrist (flexes and ulnar deviates the wrist); flexor pollicis longus on the thumb side of wrist (flexes the thumb interphalangeal joint); and flexor digitorum profundus tendons deep and midline (flexes the distal interphalangeal joints). The median nerve courses just deep to the palmaris longus tendon and adjacent to the flexor digitorum superficialis tendons. The ulnar artery and nerve courses just deep and medial to the flexor digitorum superficialis tendons and lateral to the flexor carpi ulnaris tendon. The radial artery courses just deep and lateral to the flexor digitorum radialis tendon.
Dagan Cloutier, MPAS, PA-C, practices in a multispeciality orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Leversedge FJ, Ditsios K, Owsly BJ, Boyer MI. Flexor tendon repair. Orthopaedic Knowledge Online Journal. 2004; 2(7).
- Thompson JC. Netter’s Concise Orthopaedic Anatomy. Philadelphia, Pa.: Saunders Elsevier; 2002.