Anatomic variations of the median nerve in carpal tunnel release (original) (raw)

Anatomical variations of Median Nerve at the wrist joint in open carpal tunnel release.

Tikrit Medical Journal 2009; 15(1):133-139

At the wrist, the median nerve passes beneath the flexor retinaculum in a restricted space between the flexor digitorum superficialis and flexor carpi radialis muscles and it supplies the thenar eminence muscles, the first two lumbricals and gives sensory innervation to the skin of the palmar aspect of the lateral three and one-half fingers, including the nail beds on the dorsum. Carpal tunnel syndrome is a well-known clinical entity and the release of the transverse carpal ligament is considered to be the treatment of choice. Both open and endoscopic release of the transverse carpal ligament has yielded satisfactory results for this syndrome. Although these procedures are very common in surgical practice, inadequate release and operative damage to neural elements are very frustrating complication for both the patient and the surgeon. From February 2006 to April 2008 at the operative theater of Tikrit Teaching Hospital, a team work of anatomist, surgeon and forensic medicine physician acting together in this study on 55 patients of carpal tunnel syndrome operated with open carpal tunnel release were evaluated to demonstrate incidental operative findings of variations of the standard median nerve anatomy. The present study revealed anatomical variations of median nerve at the wrist in 11 patients. In three patients, there was an aberrant branch arising from the ulnar side of the median nerve and piercing the ulnar margin of the transverse carpal ligament. Neural variations arising from the ulnar aspect of the median nerve were common and could be a cause of iatrogenic injury during open release. Surgeons should be aware of anomalous branches, which should be recognized and separately decompressed if needed.

Anatomic variations of the median nerve in the carpal tunnel: a brief review of the literature

Turkish Neurosurgery, 2010

Carpal tunnel syndrome (CTS) is a common focal peripheral neuropathy. Increased pressure in the carpal tunnel results in median nerve compression and impaired nerve perfusion, leading to discomfort and paresthesia in the affected hand. Surgical division of the transverse carpal ligament is preferred in severe cases of CTS and should be considered when conservative measures fail. A through knowledge of the normal and variant anatomy of the median nerve in the wrist is fundamental in avoiding complications during carpal tunnel release. This paper aims to briefly review the anatomic variations of the median nerve in the carpal tunnel and its implications in carpal tunnel surgery.

The median nerve in the carpal tunnel

Folia morphologica, 2011

A study of the variations of the course and branching pattern of the median nerve within the carpal tunnel were carried out on 60 wrists from 30 fresh cadavers autopsied in the Department of Forensic Medicine of Jagiellonian University Medical College. The results were compared with the literature. The study confirmed that the extraligamentous type of motor branch variation is most common. The transligamentous course of the nerve is of special importance: it is usually accompanied by hypertrophic muscle, and the nerve hidden within this muscle can easily be cut during transection of the retinaculum. The results proved the necessity of approaching the median nerve from the ulnar side when opening the carpal tunnel.

Morphological variations of median nerve observed in patients during carpal tunnel release surgery: A cross-sectional study conducted in a Tertiary Care Hospital of District Nowshera, Pakistan

The Professional Medical Journal, 2021

Objective: To study the morphological variations of median nerve observed in sick persons during carpal tunnel release operation. Study Design: Cross Sectional study. Setting: Qazi Hussain Ahmad Medical Complex, Nowshera. Period: One year (November, 2019 till October, 2020). Material & Methods: This Cross-sectional study was conducted after obtaining ethical approval from the Institutional Ethical Review Board (IERB), NMC in which people were tracked with mild to severe carpal tunnel symptoms for a year. Less than 24 hours after their arrival, the victims were operated on under local anesthesia in Qazi Hussain Ahmad Medical Complex, Nowshera, Pakistan. Each surgical method viewed the nerve. Branches around the carpal tunnel were seen and documented on a spreadsheet. 150 were planned. The statistics were in percentages. Results: In 150 instances, 102 (68%) were female and 48 (32%) were male. 138 (92%) individuals showed normal median nerve morphology, whereas 12 (8%) had aberrant bra...

Median nerve displacement through the carpal canal

The Journal of Hand Surgery, 1994

We determined the direct relationships between wrist position and displacement of the median nerve during active contraction of the flexor tendons at the wrist with an intact, transected transverse carpal ligament (TCL). Nine fresh cadavers were mounted in an apparatus to allow variable wrist position. Excursions of the tendons and displacement of the median nerve were measured by tracking markers with a video camera. Each limb was tested at 0", 30", and 60" of wrist extension before and after release of the TCL. Excursion of the flexor tendons required for full finger flexion ranged from 2.3 to 3.1 cm (mean, 3 cm). Median nerve displacement ranged from 0.9 to 1.4 cm (mean, 1 cm). The relationship between median nerve and flexor tendon excursion was consistently linear. Finger motion alone allows for median nerve displacement after surgery in the carpal tunnel. (

Short-Term Outcomes after Median Nerve Release for Carpal Tunnel Syndrome

International Journal of Orthopaedics, 2017

AIM: To study the short-term (considered as a 1-month period after surgery) outcomes experienced by patients following median nerve release due to carpal tunnel syndrome. MATERIAL AND METHODS: A longitudinal cohort study was performed between September 2013 and October 2014. Inclusion criteria included suffering from CTS for at least six months confirmed by clinical and electromyographyc criteria and undergoing median nerve release. Exclusion criteria were pregnancy, patients with acute CTS and patients who were not able to read or non-Spanish speakers. All participants completed the questionnaires DASH, SF-36 and a Visual Analogue Scale for Pain, preoperatively and one month after surgery. RESULTS: Thirty patients were included, 22 women and 8 men. DASH and VAS showed statistical significant differences before and after surgery (p < 0.05) whereas SF-36 did not show significant differences. CONCLUSION: This study shows that median nerve surgical release for CTS has satisfying outcomes in only one month from surgery.

The Median Nerve at the Carpal Tunnel … and Elsewhere

Journal of the Belgian Society of Radiology, 2018

The median nerve (MN) may be affected by various peripheral neuropathies, each of which may be categorized according to its cause, as either an extrinsic (due to an entrapment or a nerve compression) or an intrinsic (including neurogenic tumors) neuropathy. Entrapment neuropathies are characterized by alterations of the nerve function that are caused by mechanical or dynamic compression. It occurs because of anatomic constraints at specific locations including sites where the nerve courses through fibro-osseous or fibromuscular tunnels or penetrates a muscle. For the diagnosis of peripheral neuropathies, physicians traditionally relied primarily on clinical findings and electrodiagnostic testing with electromyography. However, if further doubt exists, clinicians may ask for an additional imaging evaluation.

Median Nerve Excursion in Response to Wrist Movement After Endoscopic and Open Carpal Tunnel Release

Purpose To compare the perioperative kinematic effects of endoscopic versus open carpal tunnel release on longitudinal excursion (gliding) and volar displacement (bowstringing) of the median nerve at the wrist region in patients with idiopathic primary carpal tunnel syndrome. Methods Sixteen hands of 13 patients were randomly assigned into 2 groups (group 1, endoscopic; group 2, open carpal tunnel release). For the measurement of gliding and bowstringing of the median nerve, a metallic marker was used. Before and after the division of the transverse carpal ligament, longitudinal excursion and volar displacement of the median nerve were calculated based on fluoroscopic imaging for each wrist. Movement was analyzed for the measurement of the marker locations. Results The mean prerelease median nerve excursion during wrist range of motion was 20 mm (range, 10 –28) in group 1 and 21 mm (range, 16 –31 mm) in group 2. The mean postrelease median nerve excursion during wrist range of motion was 20 mm (range, 13–29) in group 1 and 18 mm (range, 8 –26 mm) in group 2. There was no statistically significant difference in pre- and postrelease longitudinal excursion changes between the groups (p  .916 and p  .674, respectively). The mean prerelease volar displacement of the median nerve during wrist range of motion was 3 mm in group 1 and 4 mm in group 2; the postrelease mean values were 2 mm and 5 mm, respectively. There was no statistically significant difference between the groups with regard to pre- and postrelease volar displacement changes of the median nerve (p  .372 and p  .103, respectively). Conclusions This study demonstrated that the endoscopic release and open carpal tunnel release produce similar perioperative effects on longitudinal and volar movements of the median nerve.

Effect of Wrist Angle on Median Nerve Appearance at the Proximal Carpal Tunnel

PLOS ONE, 2015

This study investigated the effects of wrist angle, sex, and handedness on the changes in the median nerve cross-sectional area (MNCSA) and median nerve diameters, namely longitudinal diameter (D1) and vertical diameter (D2). Ultrasound examination was conducted to examine the median nerve at the proximal carpal tunnel in both dominant and nondominant hands of men (n = 27) and women (n = 26). A total of seven wrist angles were examined: neutral; 15°, 30°, and 45°extension; and 15°, 30°, and 45°flexion. Our results indicated sexual dimorphism and bilateral asymmetry of MNCSA, D1 and D2 measurements. MNCSA was significantly reduced when the wrist angle changed from neutral to flexion or extension positions. At flexion positions, D1 was significantly smaller than that at neutral. In contrast, at extension positions, D2 was significantly smaller than that at neutral. In conclusion, this study showed that MNCSA decreased as the wrist angle changed from neutral to flexion or extension positions in both dominant and nondominant hands of both sexes, whereas deformation of the median nerve differed between wrist flexion and extension.

Anatomic relations between the median nerve and flexor tendons in the carpal tunnel: MR evaluation in normal volunteers

American Journal of Roentgenology, 1989

To ascertain the dynamic changes between the median nerve and flexor tendons in the carpal tunnel, MR images of 16 wrists in eight volunteers were studied in flexion, extension, and neutral positions. TI-weighted axial Images, 600/20 (TRITE), were obtained with the wrists straight, extended at 45#{176}, and flexed at 45#{176}. Each scan was evaluated with regard to positional changes of the median nerve and flexor tendons in the carnal tunnel as well as alterations in nerve shape. In the neutral position, the median nerve was found in one of two standard positions: either anterior to the superficial flexor tendon of the index finger or interposed more posterolaterally between this tendon and the flexor pollicis longus. During extension,