Relationships of the palmar cutaneous branch of the median nerve: a morphometric study

Abstract

Treatment of carpal tunnel syndrome consists in decompression of the median nerve by section of the flexor retinaculum. Usually, this surgery improves the disease with disappearance of the symptoms. However, some painful sequelae may remain such as painful discharges, paresthesiae or permanent anesthesia of the base of the thumb or of the scar related to an injury of the palmar cutaneous branch of the median nerve (PCBm). This study was performed to define the accurate emergence and the anatomic characteristics of this nerve in relation to stable landmarks. Moreover, it assessed the importance of the visual identification of the branch during section of the flexor retinaculum. Thirty-five hands were dissected under macroscopic examination and under magnification of the thinnest branches. Measurements were performed with a caliper and the forearm in supination. Determination of the bistyloid line showed variability in the location of the distal wrist crease. Thus, it could not be used as a landmark to locate the PCBm. The palmar cutaneous branch is the distal collateral branch of the median nerve in the forearm. It emerges on its radial side, on average 44.3 mm before the bistyloid line. It courses in line with the third finger and perforates the antebrachial aponeurosis about 5.7 mm from the bistyloid line. This emergence can be located in the palm, where it can be injured if the incision is performed in line with the third finger. The PCBm usually ends in the palm by division into two or three branches. The lateral branch supplies the skin of the thenar eminence while the medial, usually shorter branch supplies the midline part of the palm. This study has shown the importance of performing the cutaneous incision in line with the fourth finger to avoid injury to the PCBm.

The double tunnels technique: an alternative minimally invasive approach for carpal tunnel syndrome

“…1 and 2) was made distally to the proximal wrist crease, along a longitudinal line virtually drawn from the third finger web space to the wrist. 1,5 To our knowledge, the other minimally invasive techniques require larger incisions. After the skin was incised, a couple of retractors were placed perpendicular to the incision to expose a layer of subcutaneous fat.…”

“…Although the ligament was sliced blindly, it was performed within the safe zone according to the Martin classification. 1,5,23 To avoid iatrogenic damage to the nerves, it is enough to respect certain anatomical criteria. Watchmaker 35 et al showed that the palmar cutaneous branch of the median nerve appears 2.09 ± 0.31 cm from the distal wrist crease.…”

“…It extended distally to the distal wrist crease, along a longitudinal line virtually drawn from the third web space to the wrist. 1,5 Subsequently, subcutaneous fat was exposed and 2 small retractors were used to reach the longitudinally oriented fibers of the PF, which was finally incised. 25 Through 2 retractors placed deep to the fascial edges, the transverse fibers of the TCL became identifiable.…”

Epifascial accessory palmaris longus muscle

“…This activity could be responsible for hypertrophy of the belly of the APLM, causing temporary compression of median nerve or of its palmar cutaneous branch. In fact, the usual site of emergence of the palmar cutaneous branch is located at about 4-5 cm from the bistyloid line (Chaynes et al, 2004) and the muscular belly was located in the distal third of the forearm. However, during the surgical 2.…”

Nerves of the Upper Extremity

“…It is located above the flexor retinaculum and passes between the tendons of the flexor carpi radialis and palmaris longus muscles (Chaynes et al 2004). The branch arises off the radial side of the median nerve along the radial edge of the flexor digitorum superficialis, 5-7 cm proximal to the wrist crease .…”