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Hand (New York, N.Y.) Dec 2016Nerve transfers have resulted in increased interest in the microanatomy of peripheral nerves. Herein, we expand our understanding of the internal anatomy of the digital...
Nerve transfers have resulted in increased interest in the microanatomy of peripheral nerves. Herein, we expand our understanding of the internal anatomy of the digital nerve to the ulnar index and long fingers, the radial long and ring fingers, and the nerves to the second and third web spaces. The median nerve was dissected from the digital nerves to the antecubital fossa in 14 fresh upper extremities. The distance of proximal internal neurolysis of the fascicles to the second and third web space and proper digital nerves was measured relative to the radial styloid. Plexi encountered during proximal lysis were noted. Digital nerves to the ulnar index and radial long fingers were lysed 2.4 ± 0.5 cm (mean ± SD), and digital nerves to the ulnar long and the radial ring fingers were lysed 3.0 ± 0.6 cm distal to the radial styloid. Fascicles to the third web space were lysed to the takeoff of the anterior interosseous nerve, 21.1 ± 1.4 cm. Plexus groupings were encountered at 4.5 ± 1.6 cm, 8.3 ± 1.2, cm and 16.1 ± 1.9 cm proximal to radial styloid. The fascicles to the second web space were lysed to 5.0 ± 1.2 cm proximal to radial styloid where a plexus grouping was encountered. Another plexus group was found at 3.3 ± 1.3 cm. We demonstrate that extended internal neurolysis of second web space, along with the digital nerves, is technically and clinically feasible. This technique can be used to treat mixed median nerve injury in the hand and wrist.
Topics: Cadaver; Fingers; Forearm; Hand; Humans; Median Nerve; Nerve Block; Ulnar Nerve; Wrist
PubMed: 28149207
DOI: 10.1177/1558944716643290 -
Clinical Orthopaedics and Related... Nov 2015The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have...
BACKGROUND
The median and radial nerves are at risk of iatrogenic injury when performing arthroscopic arthrolysis with anterior capsulectomy. Although prior anatomic studies have identified the position of these nerves, little is known about how elbow positioning and joint insufflation might influence nerve locations.
QUESTIONS/PURPOSES
In a cadaver model, we sought to determine whether (1) the locations of the median and radial nerves change with variation of elbow positioning; and whether (2) flexion and joint insufflation increase the distance of the median and radial nerves to osseous landmarks after correcting for differences in size of the cadaveric specimens.
METHODS
The median and radial nerves were marked with a radiopaque thread in 11 fresh-frozen elbow specimens. Three-dimensional radiographic scans were performed in extension, in 90° flexion, and after joint insufflations in neutral rotation, pronation, and supination. Trochlear and capitellar widths were analyzed. The distances of the median nerve to the medial and anterior edge of the trochlea and to the coronoid were measured. The distances of the radial nerve to the lateral and anterior edge of the capitulum and to the anterior edge of the radial head were measured. We analyzed the mediolateral nerve locations as a percentage function of the trochlear and capitellar widths to control for differences regarding the size of the specimens.
RESULTS
The mean distance of the radial nerve to the lateral edge of the capitulum as a percentage function of the capitellar width increased from 68% ± 17% in extension to 91% ± 23% in flexion (mean difference = 23%; 95% confidence interval [CI], 5%-41%; p = 0.01). With the numbers available, no such difference was observed regarding the location of the median nerve in relation to the medial border of the trochlea (mean difference = 5%; 95% CI, -13% to 22%; p = 0.309). Flexion and joint insufflation increased the distance of the nerves to osseous landmarks. The mean distance of the median nerve to the coronoid tip was 5.4 ± 1.3 mm in extension, 9.1 ± 2.3 mm in flexion (mean difference = 3.7 mm; 95% CI, 2.04-5.36 mm; p < 0.001), and 12.6 ± 3.6 mm in flexion and insufflation (mean difference = 3.5 mm; 95% CI, 0.81-6.19 mm; p = 0.008). The mean distance of the radial nerve to the anterior edge of the radial head increased from 4.7 ± 1.8 mm in extension to 7.7 ± 2.7 mm in flexion (mean difference = 3.0 mm; 95% CI, 0.96-5.04 mm; p = 0.005) and to 11.9 ± 3.0 mm in flexion with additional joint insufflation (mean difference = 4.2 mm; 95% CI, 1.66-6.74 mm; p = 0.002).
CONCLUSIONS
The radial nerve shifts medially during flexion from the lateral to the medial border of the inner third of the capitulum. The median nerve is located at the medial quarter of the joint. The distance of the median and radial nerves to osseous landmarks doubles from extension to 90° flexion and triples after joint insufflation.
CLINICAL RELEVANCE
Elbow arthroscopy with anterior capsulectomy should be performed cautiously at the medial aspect of the joint to avoid median nerve lesions. Performing arthroscopic anterior capsulectomy in flexion at the lateral aspect of the joint and in slight extension at the medial edge of the capitulum could enhance safety of this procedure.
Topics: Aged; Aged, 80 and over; Anatomic Landmarks; Arthroscopy; Biomechanical Phenomena; Cadaver; Elbow Joint; Female; Humans; Insufflation; Male; Median Nerve; Patient Positioning; Peripheral Nerve Injuries; Radial Nerve; Radiography; Range of Motion, Articular
PubMed: 26152782
DOI: 10.1007/s11999-015-4442-3 -
Neurology India 2021
Topics: Hamartoma; Humans; Lipoma; Median Nerve; Ulnar Nerve
PubMed: 33642316
DOI: 10.4103/0028-3886.310107 -
Biomedical Papers of the Medical... Dec 2009In our work we present and describe the variation of the course of the median nerve found in both upper limbs of one of the cadavers in our Institute of Anatomy (Medical...
AIMS AND METHODS
In our work we present and describe the variation of the course of the median nerve found in both upper limbs of one of the cadavers in our Institute of Anatomy (Medical Faculty, Comenius University, Bratislava, Slovakia) during the students' dissection of the peripheral nerves and vessels.
RESULTS AND CONCLUSION
This non-standard course of the median nerve was compared with a standard course described in the anatomical literature and atlases, and confronted with the variations of the median nerve found and its course described in the available literature. We also provide some clinical implications of such peripheral nerve variability because understanding such anomalies is important in the diagnosis of unexplained clinical signs and symptoms as well as during nerve blocks and certain surgical procedures around the neck and proximal arm.
Topics: Cadaver; Humans; Male; Median Nerve; Middle Aged
PubMed: 20208972
DOI: 10.5507/bp.2009.052 -
Hand (New York, N.Y.) May 2022The aims of this study were 2-fold: (1) to assess the morphological change of the median nerve in patients with carpal tunnel syndrome (CTS) preoperatively and at 6 and...
Relationship Between Morphological Change of Median Nerve and Clinical Outcome Before and After Open Carpal Tunnel Release: Ultrasonographic 1-Year Follow-up After Operation.
The aims of this study were 2-fold: (1) to assess the morphological change of the median nerve in patients with carpal tunnel syndrome (CTS) preoperatively and at 6 and 12 months postoperatively; and (2) to analyze correlation between the changes in ultrasonographic findings and the changes in clinical findings after surgical decompression. Of the 28 patients with CTS, 34 wrists were treated with open carpal tunnel release. We evaluated them using the Boston questionnaire, Japanese Society for Surgery of the Hand Version of the Quick Disability of the Arm, Shoulder, and Hand questionnaire, nerve conduction study (NCS), and ultrasound preoperatively and at 6 and 12 months postoperatively. We measured the cross-sectional area (CSA) of the median nerve at the level of the proximal inlet of the carpal tunnel (CSAc) and more proximally at the level of the distal radioulnar joint (CSAd). Paired tests and repeated measures analysis of variance of ranks were used to identify changes over time. The Spearman correlation coefficient by rank test was used for the analysis of the relation between the amount of change of CSA and the patient-rated questionnaire score and NCS findings. Findings for CSAc, CSAd, and NCS and patient-rated outcomes at 6 and 12 months postoperatively were significantly lower than their preoperative values. However, no significant correlation was found between the postoperative changes in CSAc, CSAd, and clinical variables obtained preoperatively and postoperatively. Evaluation of sonographic imaging might not be helpful for assessing clinical conditions in patients with CTS after surgical decompression.
Topics: Carpal Tunnel Syndrome; Follow-Up Studies; Humans; Median Nerve; Ultrasonography; Wrist
PubMed: 32643958
DOI: 10.1177/1558944720937367 -
Journal of Physiological Anthropology Aug 2019High-resolution ultrasound is being widely used in carpal tunnel examination to understand morphological and biomechanical characteristics of the median nerve and...
BACKGROUND
High-resolution ultrasound is being widely used in carpal tunnel examination to understand morphological and biomechanical characteristics of the median nerve and surrounding anatomy structures.
MAIN BODY
Healthy young and elderly men were recruited. The median nerve at proximal wrist region was examined by ultrasound imaging technique. A total of seven wrist angle was examined. Generally, the median nerve cross-sectional area of the elderly group is significantly larger than the young group.
SHORT CONCLUSION
Wrist posture in greater flexion or extension caused a larger decrease in the median nerve cross-sectional area across both groups.
Topics: Adult; Aged; Aging; Hand; Humans; Male; Median Nerve; Posture; Ultrasonography; Wrist; Young Adult
PubMed: 31395098
DOI: 10.1186/s40101-019-0201-6 -
Scientific Reports Sep 2020There are conflicting hypotheses regarding the initial pathogenesis of carpal tunnel syndrome (CTS). One hypothesis characterizes it as inflammation of the median nerve...
There are conflicting hypotheses regarding the initial pathogenesis of carpal tunnel syndrome (CTS). One hypothesis characterizes it as inflammation of the median nerve caused by compression, while another hypothesis characterizes CTS as non-inflammatory fibrosis of the subsynovial connective tissue (SSCT). This study aimed to investigate the differences in the ultrasonography parameters before and after a steroid injection, which is effective for CTS, to elucidate the initial pathogenesis of CTS and the mechanisms of action of the injected steroid. Fourteen hands from 14 healthy participants and 24 hands from 24 participants with mild CTS were examined. Dynamic movement and morphology of the median nerve before and after steroid injection were measured. There was no significant difference in the normalized maximal distance of the median nerve, which reflects the degree of fibrosis in the SSCT indirectly, during finger and wrist movements before and after the injection among patients with CTS (p > 0.05). Among the parameters that indirectly reflects the degree of median nerve compression, such as normalized maximal change in the aspect ratio of the minimum-enclosing rectangle (MER), maximal change in the median nerve perimeter, and maximal value of the median nerve cross-sectional area (CSA), statistically significant differences were not observed between values of the normalized maximal change in the aspect ratio of the MER and maximal change in the median nerve perimeter, during finger and wrist movements recorded before and after the injection in patients with CTS (p > 0.05). However, multivariate logistic regression analysis revealed that the change in the normalized maximal value of the median nerve CSA, according to finger and wrist movement was correlated with the administration of the steroid injection (p < 0.05). In conclusion, compared to that noted before steroid injection, the median nerve CSA noted during finger and wrist movements changed significantly after injection in patients with mild CTS. Given the improvement in median nerve swelling after steroid injection, but no improvement in the movement of the median nerve during finger and wrist movements, median nerve swelling due to compression (rather than fibrosis of the SSCT may be the initial pathogenesis of early-stage (mild) CTS, and the fibrous changes around the median nerves (SSCT) may be indicative of secondary pathology after median nerve compression. Further studies are required to validate the findings of our study and confirm the pathogenesis of CTS.
Topics: Aged; Carpal Tunnel Syndrome; Cross-Sectional Studies; Female; Humans; Injections; Male; Median Nerve; Middle Aged; Movement; Steroids; Ultrasonography; Wrist
PubMed: 32973181
DOI: 10.1038/s41598-020-72757-2 -
Journal of Ultrasound Dec 2017Peripheral nerves frequently travel close to the bone surface and are, therefore, prone to elastosonographic "bone-proximity" hardening artifacts. The impact of these...
PURPOSE
Peripheral nerves frequently travel close to the bone surface and are, therefore, prone to elastosonographic "bone-proximity" hardening artifacts. The impact of these artifacts on quantitative measurements of median nerve stiffness performed by shear wave elastosonography has not been explored. Our aim was to assess normal median nerve stiffness values at various locations.
MATERIALS AND METHODS
Thirty-six healthy volunteers (24 women and 12 men) aged between 25 and 40 years were evaluated. Two operators performed the evaluation: one expert (6 years of ultrasound experience) and one inexperienced operator (6 months' experience). The nerve was sampled in cross-section at three different locations: mid-forearm, immediately before the carpal tunnel and within the tunnel. The ultrasound scanner was equipped with a 14-MHz linear probe. The Shear Wave module was activated in one-shot mode. Measurements were performed using a ROI corresponding to the diameter of the nerve.
RESULTS
The mean values of stiffness of the medial nerve were 32.26 kPa ± 18.60 within the carpal tunnel, 22.20 kPa ± 9.84 at the carpal tunnel inlet and 7.62 kPa ± 7.38 in the forearm. Inter-observer agreement assessed using the intraclass correlation coefficient (ICC) was "moderate" within the carpal tunnel (ICC = 0.44), "moderate" at the carpal tunnel inlet (ICC = 0.41) and "fair" in the forearm (ICC = 0.38).
CONCLUSIONS
The stiffness of the median nerve progressively increases in its distal portions, where the nerve approaches the bone surface. Inter-observer agreement was generally good (from fair to moderate).
Topics: Adult; Artifacts; Bone and Bones; Elasticity; Elasticity Imaging Techniques; Female; Humans; Male; Median Nerve; Observer Variation; Organ Size; Professional Competence
PubMed: 29204233
DOI: 10.1007/s40477-017-0267-0 -
BMC Musculoskeletal Disorders Jul 2004Patients with upper limb pain often have a slumped sitting position and poor shoulder posture. Pain could be due to poor posture causing mechanical changes (stretch;...
BACKGROUND
Patients with upper limb pain often have a slumped sitting position and poor shoulder posture. Pain could be due to poor posture causing mechanical changes (stretch; local pressure) that in turn affect the function of major limb nerves (e.g. median nerve). This study examines (1) whether the individual components of slumped sitting (forward head position, trunk flexion and shoulder protraction) cause median nerve stretch and (2) whether shoulder protraction restricts normal nerve movements.
METHODS
Longitudinal nerve movement was measured using frame-by-frame cross-correlation analysis from high frequency ultrasound images during individual components of slumped sitting. The effects of protraction on nerve movement through the shoulder region were investigated by examining nerve movement in the arm in response to contralateral neck side flexion.
RESULTS
Neither moving the head forward or trunk flexion caused significant movement of the median nerve. In contrast, 4.3 mm of movement, adding 0.7% strain, occurred in the forearm during shoulder protraction. A delay in movement at the start of protraction and straightening of the nerve trunk provided evidence of unloading with the shoulder flexed and elbow extended and the scapulothoracic joint in neutral. There was a 60% reduction in nerve movement in the arm during contralateral neck side flexion when the shoulder was protracted compared to scapulothoracic neutral.
CONCLUSION
Slumped sitting is unlikely to increase nerve strain sufficient to cause changes to nerve function. However, shoulder protraction may place the median nerve at risk of injury, since nerve movement is reduced through the shoulder region when the shoulder is protracted and other joints are moved. Both altered nerve dynamics in response to moving other joints and local changes to blood supply may adversely affect nerve function and increase the risk of developing upper quadrant pain.
Topics: Adult; Cumulative Trauma Disorders; Female; Head Movements; Humans; Male; Median Nerve; Median Neuropathy; Posture; Reference Values; Stress, Mechanical; Ultrasonography
PubMed: 15282032
DOI: 10.1186/1471-2474-5-23 -
Arthritis Research & Therapy Feb 2022Deep learning applied to ultrasound (US) can provide a feedback to the sonographer about the correct identification of scanned tissues and allows for faster and...
BACKGROUND
Deep learning applied to ultrasound (US) can provide a feedback to the sonographer about the correct identification of scanned tissues and allows for faster and standardized measurements. The most frequently adopted parameter for US diagnosis of carpal tunnel syndrome is the increasing of the cross-sectional area (CSA) of the median nerve. Our aim was to develop a deep learning algorithm, relying on convolutional neural networks (CNNs), for the localization and segmentation of the median nerve and the automatic measurement of its CSA on US images acquired at the proximal inlet of the carpal tunnel.
METHODS
Consecutive patients with rheumatic and musculoskeletal disorders were recruited. Transverse US images were acquired at the carpal tunnel inlet, and the CSA was manually measured. Anatomical variants were registered. The dataset consisted of 246 images (157 for training, 40 for validation, and 49 for testing) from 103 patients each associated with manual annotations of the nerve boundary. A Mask R-CNN, state-of-the-art CNN for image semantic segmentation, was trained on this dataset to accurately localize and segment the median nerve section. To evaluate the performances on the testing set, precision (Prec), recall (Rec), mean average precision (mAP), and Dice similarity coefficient (DSC) were computed. A sub-analysis excluding anatomical variants was performed. The CSA was automatically measured by the algorithm.
RESULTS
The algorithm correctly identified the median nerve in 41/49 images (83.7%) and in 41/43 images (95.3%) excluding anatomical variants. The following metrics were obtained (with and without anatomical variants, respectively): Prec 0.86 ± 0.33 and 0.96 ± 0.18, Rec 0.88 ± 0.33 and 0.98 ± 0.15, mAP 0.88 ± 0.33 and 0.98 ± 0.15, and DSC 0.86 ± 0.19 and 0.88 ± 0.19. The agreement between the algorithm and the sonographer CSA measurements was excellent [ICC 0.97 (0.94-0.98)].
CONCLUSIONS
The developed algorithm has shown excellent performances, especially if excluding anatomical variants. Future research should aim at expanding the US image dataset including a wider spectrum of normal anatomy and pathology. This deep learning approach has shown very high potentiality for a fully automatic support for US assessment of carpal tunnel syndrome.
Topics: Carpal Tunnel Syndrome; Humans; Median Nerve; Neural Networks, Computer; Ultrasonography; Wrist
PubMed: 35135598
DOI: 10.1186/s13075-022-02729-6