Anatomic Aspects of the Carpal Tunnel Release Surgery

Review Article

Austin Neurosurg Open Access. 2014;1(2): 1008.

Anatomic Aspects of the Carpal Tunnel Release Surgery

Bartosz Godlewski*, Ryszard Czepko, Tomasz Gierula and Grzegorz Klauz

Department of Neurosurgery, Hospital of Saint Raphael, Poland

*Corresponding author: Bartosz Godlewski, Department of Neurosurgery, Scanmed - St. Raphael Hospital, 12 Bochenka Street, 30-693 Cracow, Poland

Received: March 05, 2014; Accepted: May 07, 2014; Published: May 08, 2014


Of all upper limb nerve entrapment syndromes, the carpal tunnel syndrome is most often treated surgically. Despite apparent technical simplicity of the procedure, failure to identify the precise anatomical relations within the operative site may result in complications and/or lack of post–operative improvement. The article presents anatomic aspects of the carpal tunnel syndrome that are important for the operating surgeon.

Keywords : Carpal tunnel syndrome; Carpal tunnel anatomy; Median nerve


Of all upper limb nerve entrapment syndromes, the carpal tunnel syndrome (CTS) is most frequently treated surgically. In carpal tunnel syndrome, the median nerve is compressed within the carpal tunnel distally – above the distal carpal line. CTS chiefly affect individuals between 40 and 60 years of age, with a female–to–male ratio of 4:1. It is bilateral in more than 50% of patients and tends to be more severe in the dominant limb. The most characteristic symptoms are tingling and numbness in the hand and fingers in the median nerve distribution. The symptoms usually occur during the night and often wake the patient up. The pain becomes more intense on raising the limb or flexing the wrist. Lowering the limb brings relief. Over time, precise grip becomes difficult and there may be atrophy of thenar muscles.

The treatment of this syndrome is initially conservative with nonsteroidal anti–inflammatory drugs, rest, neutral position splints and steroid injection into the tunnel. Surgical treatment is indicated in patients who did not improve with conservative treatment, patients with thenar atrophy or electrophysiological evidence of denervation [1–4].

Median Nerve Topography in the Carpal Area

In the region of the carpal line, the median nerve projects medially to the tendon of the radial flexor muscle of the wrist (flexor carpi radialis, FCL) and slightly laterally and inferiorly to the tendon of the long palmar muscle (palmaris longus). In some individuals, the palmaris longus tendon and the FCL sheath, which is situated more deeply (under the transverse carpal ligament), are palpable and sometimes visible under the skin. The palmaris longus tendon lies over the transverse carpal ligament, and the FCL tendon lies under it. The median nerve can be expected to be found between these two structures, the nerve projecting as an “extension” of the 3rd finger. The median nerve courses under the transverse carpal ligament and enters the carpal tunnel. The palmaris longus tendon becomes the palmar aponeurosis. The transverse carpal ligament is continuous with the antebrachial fascia proximally and with the flexor retinaculum of the hand distally (Figure 1). The junction between the transverse carpal ligament and the flexor retinaculum is approximately 3 cm above the distal carpal line. Approximately 10–20% of the population lack a palmaris longus tendon. In these individuals, the palmar aponeurosis fuses only with the flexor retinaculum [1,5–7].