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Objective To investigate the characteristics of the palmar cutaneous branch of the median nerve (PCBMN) in patient with carpal tunnel syndrome (CTS) using high-resolution ultrasound.Methods Fourteen healthy volunteers (17 wrists) and 31 patients with CTS (41 wrists) were evaluated by high-resolution ultrasound. All patients were classified into three groups based on the electrophysiologic CTS impairment severity: mild, moderate, and severe. Using high-resolution ultrasound, the cross-sectional areas (CSAs) of the PCBMN were measured at the proximal wrist crease, bistyloid line, and distal wrist crease, and the largest CSA was defined as the maximal CSA.Results The maximal CSA of the PCBMN of the control, mild, moderate, and severe CTS groups were 0.27±0.08, 0.30±0.07, 0.35±0.10, and 0.47±0.13 mm2, respectively. The maximal CSA of the PCBMN was significantly larger in the severe CTS group than in the other groups.Conclusion The PCBMN could be concomitantly affected in patients with severe CTS.

Highlights • Palmar cutaneous branch of median nerve, potent factor for patients feeling abnormal post-operation. • Unusual case compression of palmar cutaneous branch of median nerve (PCBNN) • Anatomy of nerve and explanation of how easily its damaged. • Nerve affected by many factors. • Spotaneous formation of nodules after rupture of the palmaris tendon., Introduction We report an unusual case compression of the palmar cutaneous branch of the median nerve(PCBNN). Presentation of case A 52-year-old woman presenting with previous rupture of the palmaris longus tendon. During surgery, we found that the end of the tendon had formed nodules. After removing the nodules, the PCBMN was released, and half a year later, the abnormal feelings had disappeared. Discussion We aim to remind surgeons of this type of compression and to highlight the importance of maintaining vigilance in order to avoid nerve injury. Conclusion PCBMN needs to be paid more attention and damaged tendons should be repaired.

Background The innervated radial artery superficial palmar branch (iRASP) flap was designed to provide consistent innervation by the palmar cutaneous branch of the median nerve (PCMN) to a glabrous skin flap. The iRASP flap is used to achieve coverage of diverse volar defects of digits. However, unexpected anatomical variations can affect flap survival and outcomes.Methods Cases in which patients received iRASP flaps since April 1, 2014 were retrospectively investigated by reviewing the operation notes and intraoperative photographs. The injury type, flap dimensions, arterial and neural anatomy, secondary procedures, and complications were evaluated.Results Twenty-eight cases were reviewed, and no flap failures were observed. The observed anatomical variations were the absence of a direct skin perforator, large-diameter radial artery superficial palmar branch (RASP), and the PCMN not being a single branch. Debulking procedures were performed in 16 cases (57.1%) due to flap bulkiness.Conclusions In some cases, an excessively large RASP artery was observed, even when there was no direct skin perforator from the RASP or variation in the PCMN. These findings should facilitate application of the iRASP flap, as well as any surgical procedures that involve potential damage to the PCMN in the inter-thenar crease region. Additional clinical cases will provide further clarification regarding potential anatomical variations.

Objective To evaluate the relationship between the palmar cutaneous branch of median nerve (PCBMN) and surrounding anatomical structures by using high-resolution ultrasound (HRUS) to assess the risk of PCBMN injury. Methods The PCBMN course and the characteristics of bilateral distal forearms and wrists of 30 healthy volunteers were identified. The distance between PCBMN and other anatomical structures at three different levels along its course were measured using HRUS. Moreover, the depth of PCBMN from skin and its cross-sectional area (CSA) were measured. Results HRUS showed the PCBMN in all subjects. PCBMN branched off from the radial aspect of the median nerve (MN) at 4.69±0.89 cm proximal to the bistyloid line (BSL) and extended radially toward the flexor carpi radialis (FCR) tendon. PCBMN was within the ulnar edge of FCR tendon sheath, and became more superficial and perforated the antebrachial fascia between the FCR tendon laterally and the palmaris longus (PL) tendon medially. PCBMN was located at 4.08±0.72 mm on the ulnar aspect of the FCR tendon and 4.78±0.36 mm radially on the PL tendon at BSL. At the distal wrist crease level, the PCBMN was located at 5.68±0.58 mm on the ulnar side of the FCR tendon. The PCBMN depth from skin at BSL and its branching point was 1.92±0.41 and 7.95±0.79 mm, respectively. The PCBMN CSA was 0.26±0.15 mm2 at BSL. Conclusion HRUS can be used to identify PCBMN and its relationship with other anatomical structures. Our data can be used to predict PCBMN location, and prevent complications associated with invasive procedures involving the wrist.

Background Carpal tunnel syndrome is a common presentation to surgical outpatient clinics. Treatment of carpal tunnel syndrome involves surgical division of the flexor retinaculum. Palmar and recurrent branches of the median nerve as well as the superficial palmar arch are at risk of damage. Methodology Thirteen cadavers of Sri Lankan nationality were selected. Cadavers with deformed or damaged hands were excluded. All selected cadavers were preserved with the conventional arterial method using formalin as the main preservative. Both hands of the cadavers were placed in the anatomical position and dissected carefully. We took pre- determined measurements using a vernier caliper. We hypothesized that the structures at risk during carpal tunnel decompression such as recurrent branch of the median nerve and superficial palmar arch can be protected if simple anatomical landmarks are identified. We also hypothesized that an avascular area exists in the flexor retinaculum, identification of which facilitates safe dissection with minimal intra operative bleeding. Therefore we attempted to characterize the anatomical extent of such an avascular area as well as anatomical landmarks for a safer carpal tunnel decompression. Ethical clearance was obtained for the study. Results In a majority of specimens the recurrent branch was a single trunk (n =20, 76.9%). Similarly 84.6% (n = 22) were extra ligamentous in location. Mean distance from the distal border of the TCL to the recurrent branch was 7.75 mm. Mean distance from the distal border of TCL to the superficial palmar arch was 11.48 mm. Mean length of the flexor retinaculum, as measured along the incision, was 27.00 mm. Mean proximal and distal width of the avascular area on TCL was 11.10 mm and 7.09 mm respectively. Conclusion We recommend incision along the radial border of the extended ring finger for carpal tunnel decompression. Extending the incision more than 8.16 mm proximally and 7.75 mm distally from the corresponding borders of the TCL should be avoided. Incision should be kept to a mean length of 27.0 mm, which corresponds to the length of TCL along the above axis. We also propose an avascular area along the TCL, identification of which minimizes blood loss.