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Introduction/aims: Ultra high-frequency ultrasound (UHFUS) has been demonstrated to allow easy visualization and quantification of median and digital nerve fascicles; however, there is a lack of normative data for other upper limb nerves. The purpose of this study was to use UHFUS to establish normative reference values and ranges for fascicle count and density within selected upper extremity nerves., Methods: Twenty-one healthy volunteers underwent sonographic examination of the ulnar, superficial branch of the radial, and radial nerves on one upper limb using UHFUS with a 48 MHz linear transducer. The number of fascicles in each peripheral nerve and fascicle density were assessed., Results: The mean fascicle number and fascicle density for each of the measured nerves was ulnar nerve at the wrist 11.7 and 2.0, ulnar nerve at the elbow 9.2 and 1.1, superficial branch of the radial nerve 7.3 and 2.5, and radial nerve at the spiral groove 4.2 and 0.8. A single significant association was observed between CSA and fascicle number in the ulnar nerve at the wrist (p = .023, r = 0.66). Neither fascicle number nor density could be predicted by age, sex, height, weight, or body mass index., Discussion: UHFUS may help to establish a baseline of normative data on upper limb nerves that are not frequently biopsied due to their mixed motor and sensory functions and has the potential for increased understanding of nerve fascicular anatomy to improve diagnostic accuracy of focal nerve lesions, particularly those with selective fascicular involvement., (© 2024 Wiley Periodicals LLC.)

The dorsal capsule of the wrist and the DCSS may play a significant role in the conduction of nerve signals transmitted from proprioceptors present in SL to PIN, which is located above the dorsal capsule. Hence, this study aimed to determine if nerve fibers of PIN penetrate inside the dorsal capsule. The dorsal capsules of the wrist were dissected from both sides from 15 cadavers. Eventually, 30 dorsal capsules were dissected. It can be concluded that the PIN nerve fibers penetrate the dorsal capsule of the wrist, as the penetration was noticeable in every part evaluated. The present study proves that afferent fibers from the mechanoreceptors of the SLIL potentially pass through the DCSS and subsequently through the dorsal capsule of the wrist to the PIN. This knowledge can surely be of great use for hand surgeons that perform procedures on the dorsal wrist. [ABSTRACT FROM AUTHOR]

Introduction: The distal Posterior Interosseous Nerve (PIN) plays an important part in the sensory innervation of the wrist joint. Introduction of the arthroscopy portals during wrist arthroscopy might injure the PIN. The anatomic variation in the trajectory of the PIN and the proximity to the dorsal arthroscopy portals have not yet been fully explored., Materials and Methods: Computer assisted surgical anatomy mapping (CASAM) is a technique to digitally compute and merge photographic images using anatomic landmarks and visualize variation in anatomy. A standard wrist arthroscopy procedure was carried out on eight cadaver forearms. CASAM was used to map the trajectory of the distal PIN and measure the distance to bony landmarks and the nearest wrist arthroscopy portals. Descriptive statistics were provided for anatomical measurements., Results: CASAM illustrated great variation in the PIN trajectories between the specimens. The mean distance from the PIN to Lister's tubercle was 9 ​mm (range 3-14, SD 3.9), the distance to the ulnar styloid was 27 ​mm (range 23-32, SD 3.3). None of the nerves showed signs of iatrogenic injury from placement of the arthroscopy portals. The 3-4 portal and the 6R portal were closest to the PIN with a respective mean distance of 9 ​mm (range 4-15, SD 3.8) and 19 ​mm (range 13-22, SD 3.2)., Conclusion: CASAM demonstrated the importance of understanding nerve anatomy variations and offered insight into which arthroscopy portals are most likely to damage the distal PIN. However, we conclude that the overall risk of PIN injury from wrist arthroscopy is low due to the proximity to the portals., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© 2024 Society for Indian Hand Surgery and Micro Surgeons. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Double crush syndrome refers to a nerve in the proximal region being compressed, affecting its proximal segment. Instances of this syndrome involving ulnar and cubital canals during ulnar neuropathy are rare. Diagnosis solely through clinical examination is challenging. Although electromyography (EMG) and nerve conduction studies (NCS) can confirm neuropathy, they do not incorporate inching tests at the wrist, hindering diagnosis confirmation. We recently encountered eight cases of suspected double compression of ulnar nerve, reporting these cases along with a literature review., Methods: The study included 5 males and 2 females, averaging 45.6 years old. Among them, 4 had trauma history, and preoperative McGowan stages varied. Ulnar neuropathy was confirmed in 7 cases at both cubital and ulnar canal locations. Surgery was performed for 4 cases, while conservative treatment continued for 3 cases., Results: In 4 cases with wrist involvement, 2 showed ulnar nerve compression by a fibrous band, and 1 had nodular hyperplasia. Another case displayed ulnar nerve swelling with muscle covering. Among the 4 surgery cases, 2 improved from preoperative McGowan stage IIB to postoperative stage 0, with significant improvement in subjective satisfaction. The remaining 2 cases improved from stage IIB to IIA, respectively, with moderate improvement in subjective satisfaction. In the 3 cases receiving conservative treatment, satisfaction was significant in 1 case and moderate in 2 cases. Overall, there was improvement in hand function across all 7 cases., Conclusion: Typical outpatient examinations make it difficult to clearly differentiate the two sites, and EMG tests may not confirm diagnosis. Therefore, if a surgeon lacks suspicion of this condition, diagnosis becomes even more challenging. In cases with less than expected postoperative improvement in clinical symptoms of cubital tunnel syndrome, consideration of double crush syndrome is warranted. Additional tests and detailed EMG tests, including inching tests at the wrist, may be necessary. We aim to raise awareness double crush syndrome with ulnar nerve, reporting a total of 7 cases to support this concept., (© 2024. The Author(s).)

Background: The aim of this study was to assess the innervation of the dorsal articular capsule of the wrist using modified Sihler's staining.Materials and Methods: Thirty dorsal wrist capsules were collected from 15 donors (both sides) within 12 hours of death. All the capsules were collected in the same manner - using the dorsal incision. The specimens were stained according to the protocol of the modified Sihler's staining technique. The preserved capsules were analysed under 8-16× magnification of an optical microscope for the presence of major nerve trunks, their major and minor branches, and nerve connections.Results: The range of innervation visualised was that the posterior interosseous nerve innervated approximately 60% of the central part; the remaining area was innervated by the dorsal sensory branch of the radial nerve and medial antebrachial cutaneous nerve. The constant findings were the branches departing from the ulnar side of the posterior interosseous nerve and from the radial side, with an exception seen in 2 cases. A communicans branch between the posterior interosseous nerve and medial antebrachial cutaneous nerve was seen in all the specimens. The posterior interosseous nerve innervation extended beyond the level of the carpometacarpal joints II-V.Conclusions: The modified Sihler's staining technique allows for transparent visibility of the nerves that innervate the dorsal wrist capsule. However, it does not allow as accurate assessment as does histological examination, especially regarding the evaluation of nerve endings. Nevertheless, this method provides a significantly larger area of nerve observation than is provided by histological examination. [ABSTRACT FROM AUTHOR]

Three commonly used approaches to the forearm in orthopedic surgery are Henry's, Thompson's, and the ulnar approach, each of which has the potential to cause injury to nerves around the wrist. Preserving these nerves is important to prevent complications such as neuroma formation and motor and sensory changes to the hand. We conducted a review of the literature to assess the nerves at risk and whether 'safe zones' exist to avoid these nerves. An independent reviewer conducted searches in Embase and MEDLINE of the literature from 2010 to 2020. A total of 68 papers were identified, with 18 articles being included in the review. Multiple nerves were identified as being at risk for each of the approaches described. In the anterior approach, the palmar cutaneous branch of the median nerve (PCBMN) is most at risk of injury. An incision immediately radial to the flexor carpi radialis (FCR) or directly over the FCR is most likely to avoid injury to both superficial branch of the radial nerve (SBRN) and PCBMN. With Thompson's approach, the safest zone for an incision is directly over or slightly radial to Lister's tubercle to avoid injury to SBRN and lateral cutaneous nerve of the forearm. For the ulnar approach, a safe zone was shown to be on the ulnar side of the wrist around the ulnar styloid (US) when the forearm was in supination or a neutral position to avoid injury to the dorsal branch of the ulna nerve (DBUN). Care must be taken around the US due to the density of nerves and the proximity of the last motor branch of the posterior interosseous nerve to the ulnar head. This review highlighted the proximity of nerves to the three most common surgical incisions used to access the forearm. In addition, anatomical variations may exist, and each of the nerves identified as being at risk has multiple branches. Both factors increase the potential of intraoperative damage if the anatomy is not properly understood. The surgeon must adhere carefully to the established approaches to the wrist and distal forearm to minimize damage to nerves and optimize surgical outcomes for the patient., (© 2023 American Association of Clinical Anatomists and British Association of Clinical Anatomists.)

The aim of the study was to assess the course of posterior interosseous nerve in the wrist capsule in the transparent method of nerve staining. Materian and Methods: Thirty dorsal wrist capsules were collected bilaterally from 15 donors (thirty capsules) within 12 hours of death. By the dorsal incision the capsules were collected in the same manner. The specimens were stained according to the protocol of modified Sihler's staining technique. The preserved capsules were analysed under 8--16x magnification of optical microscope for the presence of major posterior interosseous nerve trunks, their major and minor branches, and nerve connections. Results: Three main types of nerve course were identified within the joint capsule. Type I -- the most common, with the presence of a single trunk with the excursion of the first main branch on the radial side, two main branches on the ulnar side, the presence of the prevailing number of small branches on the radial side and the presence of 3--4 branches extending beyond the level of the carpo-metacarpal joints. Type II with the presence of two main nerve trunks, running almost in parallel with the first main branch on the radial side, two main branches on the ulnar side with presence of a predominant number of small branches on the radial side and the presence of 3-4 branches running beyond the level of carpo-metacarpal joints. Type III (least often) with the presence of crossed main nerve trunks. Conclusion: The modified Sihler's staining technique allows for transparent visibility of the nerves innervation the dorsal wrist capsule. However does not allow accurate assessment as histological examination, especially in evaluation of nerve endings, but it gives a significantly larger area of nerve observation. [ABSTRACT FROM AUTHOR]

The T1 nerve root is not routinely thought of as innervating the extensors of the thumb and fingers. Work by Bertelli and Ghizoni proposed that the pattern of brachial plexus paralysis with intact hand function and thumb and finger extensors traditionally attributed to C5/6/7 root injury is in fact a C5/6/7/8 injury, with only T1 remaining intact - a 'T1 hand'. This case presents a 19-year-old male who was stabbed in the neck; exploratory surgery determined complete transection of the brachial plexus, with only the T1 nerve root remaining intact. Clinical examination demonstrated grade M4 pronation (with pronator quadratus), wrist extension (with extensor carpi ulnaris), thumb and finger extension (with extensor policis longus and brevis, extensor digitorum communis and extensor index proprius), wrist flexion (with palmaris longus), finger flexion (with flexor digitorum superficialis and profundus), thumb flexion (with flexor policis longus), and thenar and hypothenar muscles. Extensor carpi radialis longus and brevis, flexor carpi radialis and flexor carpi ulnaris were paralyzed. Triceps scored M2. This case provides unequivocal evidence that the T1 root provides significant innervation to the extrinsic thumb and finger extensors.

While handcuffs and zip ties are common methods of physical restraint used by law enforcement, they have been noted to damage soft tissue and bony structures of the hand and wrist. This paper seeks to characterize the safety of physical restraints by summarizing its effects on hand and wrist function and disability. Relevant studies were gathered through an independent double selection and extraction process using 3 electronic databases (EMBASE, MEDLINE, and CINAHL) from database inception to June 19, 2020. A total of 16 studies involving 807 participants were included. Lesion to the superficial branch of the radial nerve was the most commonly reported injury noted in 82% (42/55) of hands examined. A total of 6% (5/77) of examined hands had bony injury, including 3 radial styloid fractures and 2 scaphoid fractures. Both studies on zip ties noted presence of handcuff neuropathy, with 1 case report documenting severe rapidly progressing ischemic monomelic neuropathy. Overall, the use of handcuffs and zip ties is associated with entrapment neuropathies and bony injury to the hand and wrist. Further studies of higher quality evidence are necessary to understand the effects of physical restraint on hand function and disability., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome. Although prior studies have explored the anatomic changes of the median nerve and carpal arch with different wrist deviations and positionings, the change in safe zone distance between the median nerve and ulnar artery with ulnar or radial wrist deviations has not been adequately investigated., Objective: To identify the optimal wrist positioning that increases the safe zone distance between the median nerve and ulnar artery using ultrasound in patients with CTS., Design: Retrospective cohort study., Setting: Quaternary medical center multidisciplinary outpatient hand clinic., Participants: Twenty five patients (41 wrists) with clinical CTS who received an electrodiagnostic study (EDX) to evaluate CTS within 1 year prior to enrollment., Interventions: Ultrasound-identified safe zone distance measurements were obtained in each patient between the ulnar aspect of the median nerve and the radial aspect of the ulnar artery with the wrist in neutral radial-ulnar deviation as well as in passive ulnar and radial deviation., Main Outcome Measure: The ultrasound-identified safe zone distance with the wrist in each of the three positions., Results: The interstructural safe zone distance was significantly greater when measured in the ulnarly deviated position (1.08 cm) compared with either the neutral (0.61cm, p < .001) or radially deviated positions (0.52 cm, p < .001). Interstructural safe zone distance did not differ between those with normal, mild, moderate, or severe classifications of pathology, or between dominant and nondominant limbs., Conclusion: This study demonstrates that the ultrasound-measured interstructural safe zone distance was significantly greater in the ulnarly deviated position than in either the neutral position or radially deviated position. These findings may lead to improvement in the safety of ultrasound-guided injections., (© 2022 American Academy of Physical Medicine and Rehabilitation.)

Backgroud: The purpose of this study was to compare the 1,2 with a novel 2R portal in terms of proximity to critical structures., Methods: Wrist arthroscopy was performed on 8 fresh frozen cadavers via the 1,2 and 2R portals. External anatomy was then dissected under loupe magnification. The closest distance between the portals and surrounding anatomical structures was measured in millimeters using digital calipers., Results: The 1,2 portal was significantly closer to radial artery and first extensor compartment tendons than the 2R portal. The radial artery was on average 1.32 mm from the 1-2 portal and 14.25 mm from the 2R portal. The 2R portal was significantly closer to the second and third extensor compartment tendons. The closest branch of the superficial branch of the radial nerve (SBRN) was on average 2.04 mm from the 1-2 portal and 7.59 mm from the 2R portal, but this was not statistically significant., Conclusions: We advocate using the 2R portal preferentially to the 1,2 portal when treating radial sided wrist pathology to decrease the risk of iatrogenic radial artery and SBRN injury.

Objective: Decompression of the median nerve by complete endoscopic release of the transverse carpal ligament (TCL) and the distal antebrachial fascia. Minimization of surgical trauma results in decreased postoperative morbidity and earlier return to work and daily activities., Indications: Symptomatic carpal tunnel syndrome., Contraindications: Revision surgery after open or endoscopic procedure, rheumatic diseases., Surgical Technique: Small transverse incision at the ulnar border of the palmaris longus tendon, and proximal to the distal wrist flexion crease. Exposure and incision of the antebrachial fascia, dilatation of the carpal tunnel and dissection of synovial tissue from the undersurface of the TCL. With the wrist in extension, the endoscopic blade assembly with integrated camera is inserted into the canal. Exposure of TCL and short incision in the middle portion. Gradually, dissection of the distal portion of the TCL then completion by retraction of the blade distally to proximally., Postoperative Management: Slightly compressive dressing, selfcare on day 1 after procedure., Results: More than 25 years of experience, more than 8000 treated patients, and 3 documented cases with intraoperative lesions of the median nerve requiring revision. High acceptance and patient satisfaction in AQS1 patient-reported surveillance., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: The treatment of carpal tunnel syndrome (CTS) by sectioning the transverse carpal ligament (TCL) is not exempt from complications. Some nerve branches may be damaged by the incision. The aim of this study is to identify and map the TCL nerve endings, serving as a guide for sectioning this structure in a zone with less nerve ending density. Methods: Ten TCLs were obtained from fresh frozen cadavers. The TCLs were measured, divided into 3 equal bands (radial, central, and ulnar), and submitted to cryostat sectioning. The sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 and confocal microscopy analysis. Results: All the specimens contained type I and type IV mechanoreceptors. Neural elements occupied 0.695 ± 0.056% of the ligament area. The density of the neural elements was greater in the radial, followed by the ulnar and central bands, with 0.730 ± 0.083%, 0.686 ± 0.009%, and 0.669 ± 0.031%, respectively. Conclusion: The present findings suggest that the region with the least potential for neural element injury during TCL release is the central third near the transition with the ulnar third. When performed distally to proximally with a slight inclination from the radial to the ulnar, this release compromises the lowest nerve element density. Topographically, the proximal limit of the release is the distal wrist crease, while the distal limit is the intersection of Kaplan cardinal line and the axis of the third webspace.

Purpose: To examine the afferent pathways of the scapholunate interosseous ligament (SLIL)–generated stimuli and their contribution to the overall carpal proprioception. Methods: We examined 5 selected patients with preganglionic global root avulsion, confirmed by previous brachial plexus exploration, during the initial stage of carpal arthrodesis surgery. Despite their anesthetic-flail extremity, both the distal axon and the ganglionic cell were intact and able to transfer afferent stimuli. We placed electrodes subcutaneously over the adjacent areas of the ulnar, median, and radial nerves at the elbow region and performed an intraoperative neurophysiologic study. We studied the homologous sensory action potentials (SAPs) generated at the wrist in relaxation, flexion, extension, radial deviation, and ulnar deviation positions at each nerve and repeated them in 2 stages. The first took place with the SLIL intact and the second with the SLIL lacerated. The noise from the rest of the wrist elements was digitally eliminated. Results: After the SLIL laceration, SAP intensities recorded at the median nerve in every wrist position were reduced. The radial and ulnar nerves showed differences of lesser degrees between the recorded SAP intensities before and after the ligament sectioning in every carpal position, with only the radial nerve following a specific pattern. The SAP intensity recorded at the median nerve in every carpal motion after the SLIL laceration was similar to the SAP intensity at relaxation with the SLIL intact, whereas recordings of various intensities were present for the radial and ulnar nerves. Conclusions: The SLIL generates proprioceptive stimuli at every wrist position. The main innervation of the whole SLIL derives from the anterior interosseous nerve; a partial contribution of the posterior interosseous nerve focused on the dorsal subregion of the ligament may also be present. [ABSTRACT FROM AUTHOR]

The median nerve is an important sensory and motor nerve of the arm and is not infrequently associated with diagnostic and therapeutic misjudgements. A bifid median nerve as a coincidental finding in traumatology is another rarity and is mostly found during various elective procedures, such as carpal tunnel splitting. We report on a patient with a bifid median nerve who sustained a laceration wound near the carpal tunnel due to a domestic accident., (© 2021. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Posterior interosseous nerve palsy (PINP) is a disorder caused by damage to the posterior interosseous nerve, resulting in weak extension of the wrist and fingers as well as radial deviation of the wrist., Methods: This study analyzed a new type of evaluation for PINP in hopes of increasing ease of diagnosis and earlier detection of the disorder. The window test is performed by the examiner laying hands on the ulnar aspect of the patient's pronated forearm while the patient tries to extend the wrist. A positive test is obtained when a gap (window) appears between the examiner's forearm and the patient's hand. Laypeople, medical students, residents, and practicing providers were assessed prospectively on their ability to correctly diagnose PINP by observing one hand, by observing both hands and by using the window test., Results: The window test was consistently found to be the most effective method of evaluation, as it increased the accuracy of diagnosis in all groups surveyed. Additionally, case studies were performed using the window test on patients, further demonstrating the efficacy of the test by confirming wrist radial deviation., Conclusions: The window test introduces a reference frame making it easier to assess wrist radial deviation and offering a simple evaluation that can be administered by virtually anyone. These findings indicate that the implementation of the window test will increase the accuracy and effectiveness of PINP diagnosis, thus allowing early diagnosis and better management., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: It is vital to know the anatomical variations of the wrist to avoid iatrogenic injuries during carpal tunnel (CT) surgery., Purpose: To determine the anatomical variations of the median nerve (MN) and the prevalence of persistent median artery (PMA) on wrist magnetic resonance imaging (MRI)., Material and Methods: A total of 300 wrists evaluated by MRI during 2013-2015 were retrospectively identified. While branching of the MN distal to the CT is accepted as the normal anatomy, proximal to the tunnel and within the tunnel were considered as variations. The prevalence of PMA was also evaluated. The patients were assigned to groups according to age, gender, and wrist side and compared to determine whether there was any significant difference in terms of these variations. All evaluations were assessed with the shared decision of a musculoskeletal radiologist and a radiology resident., Results: Of the 300 wrists, 38 (12.7%) and 34 (11.3%) had a bifid MN proximal to the CT and within the CT, respectively. Only one nerve trifurcation was seen within the CT. The MN exhibited branching distal to the CT in 227 (76%) patients. PMA was observed in 44 (14.7%) patients. Of the 44 PMA cases, 28 (63.6%) also had a coexisting MN variation. There was no significant difference in the prevalence of MN variations and PMA in the subgroups ( P  > 0.05)., Conclusion: Nearly one in four patients (24.4%) have MN variations and 14.8% had PMA. Preoperative evaluation of these common anatomical variations with MRI will be protective against postoperative complications of CT surgery.

Introduction/aims: High-resolution ultrasound (HRUS) is the imaging method of choice to visualize peripheral nerve size, structure, and biomechanical performance. The purpose of this study was to show and quantify the effects of active and passive wrist alignment on median nerve (MN) cross-sectional area (CSA) along the forearm in a healthy population., Methods: Sixteen healthy volunteers underwent HRUS of their dominant forearm (n = 16, 10 males, 6 females, 18-55 y of age). Median nerve's CSA was assessed at four defined areas on the forearm in relation to active and passive wrist alignment., Results: Changes in wrist alignment were significantly associated with MN CSA (P < .001), regardless if the wrist was moved actively or passively. MN CSA was lowest during passive extension of the wrist joint and highest during passive flexion of the wrist joint (range: 4.5-23.2 mm 2 )., Discussion: The elasticity of nerve tissue, the loose connective tissue between the fascicles, and the paraneurium allow peripheral nerves to adapt to longitudinal strain. HRUS enables the demonstration of significant median nerve CSA changes along the forearm during active and passive wrist movement in healthy volunteers., (© 2021 Wiley Periodicals LLC.)

The aim of this study was to review the literature on the innervation of the wrist with an emphasis on pathological and therapeutic aspects. The nerves involved in wrist innervation and their mechanoreceptor endings are described. The literature over the past 30 years includes several topics that are still subjects of discussion and debate and require further research., (© 2021 American Association of Clinical Anatomists.)

Purpose: The median nerve cross-sectional area at the wrist (CSA) and the wrist-to-forearm ratio of the cross-sectional areas (WFR) are ultrasound parameters used in the diagnosis and grading of carpal tunnel syndrome. This study aimed to determine the diagnostic accuracy of the CSA and WFR as well as to compare their diagnostic value., Methods: A retrospective evaluation was conducted of a cohort of 218 patients who had undergone nerve conduction studies (NCSs) and an ultrasound of the median nerve. The examined wrists were classified into an NCS negative and three NCS positive (mild, moderate, and severe) categories. The CSA and WFR were compared across the categories., Results: The CSA and WFR were significantly smaller in the NCS negative category than in the NCS positive categories. The WFR was significantly smaller in the mild category than in the moderate category. The CSA could not be used to differentiate across the NCS positive categories., Conclusions: The CSA and WFR are satisfactorily reliable in detecting carpal tunnel syndrome, but they cannot be considered as surrogate indicators of electrophysiological severity., Competing Interests: The authors have no or conflicts of interest to disclose., (Copyright © 2020 by the American Clinical Neurophysiology Society.)

Carpal tunnel syndrome (CTS) refers to the symptoms and signs caused by the compression of the median nerve in the carpal tunnel. It can be treated by corticosteroid injection into the carpal tunnel. Two methods for injection have been employed, namely ultrasound-guided and landmark-guided injection. This systematic review and meta-analysis was conducted to compare these methods in terms of several outcomes. A search of the PubMed, Cochrane Library, and Embase databases was performed from the date of their inception to October 7, 2020 to identify randomized controlled trials (RCTs). Results for continuous variables are expressed as standardized mean differences (SMDs) with 95% confidence intervals (CIs). Analyses were performed using RevMan 5.3 software. The analysis included eight RCTs published between 2013 and 2019 with a total of 448 patients. Ultrasound-guided injection yielded more favorable results than landmark-guided injection for the Boston Carpal Tunnel Syndrome Questionnaire, Symptom Severity Scale [SMD =  - 0.43, 95% CI (- 0.68, - 0.19), P = 0.0005] and Boston Carpal Tunnel Syndrome Questionnaire, Functional Status Scale [SMD =  - 0.50, 95% CI (- 0.84, - 0.15), P = 0.005]. Ultrasound-guided corticosteroid injection is recommended for patients with CTS.

Rationale: The incidence of Martin-Gruber anastomosis ranges from 5% to 34%, which is characterized by crossing over from the median to the ulnar nerve and innervating the first dorsal interosseous, thenar or hypothenar muscles. However, the reverse Martin-Gruber anastomosis, or Marinacci anastomosis, is far less discussed and appears in recent literature., Patient Concerns: A 56-year-old man presented to the clinic of a university hospital because of left neck soreness with numbness radiating to the left lateral shoulder. The neck discomfort was aggravated while the neck rotated or tilted to the right., Diagnosis: Higher compound muscle action potential over the abductor pollicis brevis on elbow stimulation than on the wrist was found during upper limb nerve conduction velocity study. Ulnar to median anastomosis was identified., Intervention: We performed cervical spine X-ray and electrophysiological examinations and monitored the patient., Outcomes: We identified that this patient had left C5 and C6 subacute radiculopathy with active denervation and left subclinical ulnar sensory neuropathy, and verified the existence of ulnar-to-median anastomosis., Lessons: We demonstrated a pure motor ulnar-to-median anastomosis without sensory correspondence and higher CMAP over the abductor pollicis brevis on elbow stimulation of the ulnar nerve than on the wrist. The prevalence might be underestimated in a Chinese population-based published study., Competing Interests: The authors have no conflicts of interest to disclose. Patient consent: The patient provided written informed consent for the publication and use of the report., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose: Although there are many case reports on the role of ultrasonography (US) in distal ulnar nerve neuropathy (Guyon canal syndrome), there is a paucity of large series in the literature because of its rarity. During an 8-year period, 33 instances of electrodiagnostically confirmed cases underwent US imaging. These cases were analyzed to determine the role of US in uncovering the cause of distal ulnar nerve neuropathy and its contribution to further management., Methods: This was a retrospective study of patients diagnosed with distal ulnar nerve neuropathy based on electrodiagnostic criteria, who also had undergone US (measurement of the cross-sectional area and documentation of causes such as cysts and neuromas)., Results: US showed normal ulnar nerve in 5, cysts in 10, neuromas in 2, and nonspecific enlargement in 16 patients. Surgery was performed in 15 patients, and the US findings were corroborated in those with cysts and neuromas; 1 patient had an aberrant muscle, and two had fibrous bands constricting the ulnar nerve in the Guyon canal (not detected preoperatively by US imaging)., Conclusions: US imaging detected the underlying cause of distal ulnar nerve neuropathy in a significant percentage of patients, potentially contributing to effective treatment., Competing Interests: The author has no funding or conflicts of interest to disclose., (Copyright © 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Clinical Neurophysiology Society.)

Background:  Peripheral nerve pathologies of the upper extremity are increasingly assessed by high-resolution ultrasonography (HRUS), yet rapid identification of nerve segments can be difficult due to small nerve diameters and complex regional anatomy. We propose a landmark-based approach to speed up and facilitate evaluation and intervention in this region., Method:  Relevant landmarks and section planes for eleven nerve segments of the forearm, wrist and hand were defined by ultrasonography in cadaver arms before cryosection and topographical neurovascular preparation. Information on all nerve segments and a pictorial guide including anatomical cross-sections, topographical preparations and HRUS images are provided. The identification rates of these nerve segments were then assessed in 20 healthy volunteers., Results and Conclusion:  Sonographic landmarks and guidelines for the rapid identification and assessment of nerves of the forearm, wrist and hand are presented in pictorial and tabular form, including discussion of normal variants. Utilizing this overview should facilitate training, diagnostic examinations and intervention for nerves of the upper extremity., Key Points:   · High-resolution ultrasound enables assessment of peripheral nerves of the forearm, wrist and hand.. · A landmark-based approach can facilitate and speed up nerve evaluation in these regions.. · High detection rates could be reproduced using the proposed landmark-based approach.., Citation Format: · Gruber L, Loizides A, Peer S et al. Ultrasonography of the Peripheral Nerves of the Forearm, Wrist and Hand: Definition of Landmarks, Anatomical Correlation and Clinical Implications. Fortschr Röntgenstr 2020; 192: 1060 - 1072., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Introduction: Evidence for the efficacy of distal corticosteroid injection compared with proximal injection in carpal tunnel syndrome (CTS) is inadequate., Methods: We conducted a randomized, double-blind noninferiority trial of 131 wrists with CTS. Forty milligrams of methylprednisolone was injected medial to the palmaris longus tendon 2 cm proximal to the wrist crease, or at the volar aspect, 2 to 3 cm distal to the wrist crease. Proximal & distal groups received a placebo. The primary outcome was difference in CTS Symptom Severity Scale (SSS) score at 1 month. Secondary outcome measures included the difference in SSS score at 3 months, Functional Status Scale (FSS) score at 1 and 3 months, and pain of injections., Results: No significant differences were noted between groups in scores on the SSS and FSS. Pain was lower in the proximal group compared with the distal group., Discussion: Corticosteroid injections for CTS distal to the wrist are not inferior to proximal injections, yet they are more painful., (© 2020 Wiley Periodicals, Inc.)

This study aims to evaluate whether the upper extremity spasticity and hemiplegic posture have any effect on the morphology of the carpal tunnel and median nerve in stroke patients. Nerve conduction studies (NCS) were performed in 46 stroke patients and compared to those of 30 healthy controls. The cross-sectional area (CSA) of the carpal tunnel (CT) and median nerve (wrist/mid-forearm levels) was assessed by ultrasonography. The mean ages of the stroke and control group were 55.6 ± 13.5 and 56 ± 12.1 years, respectively. The median spasticity score of the forearm pronators and wrist flexor muscles was 2 (0-4) according to the Modified Ashworth Scale (MAS). The compound muscle action potential (CMAP) of the median nerve was reduced (10,093 ± 4,451 mV) when compared to non-paretic side (11,615 ± 4,397 mV) (p:0.02) and the CSA of the CT was thinner on the paretic side (1.9 ± 0.3 cm 2 vs 2.08 ± 0.2 cm 2 ) (p:0.03). Pronator spasticity had no significant effect on the CSA of the median nerve and NCS at the forearm level. The CSA of the median nerve at the wrist was significantly thicker in patients with the wrist flexor spasticity graded II (MAS) and above compared to those with spasticity graded I and below (9.5 ± 1.7 mm 2 and 8.7 ± 1.7 mm 2 respectively) (p:0.03). However, the thickening of the median nerve didn't cause significant abnormalities in NCS. This study shows that in stroke patients, wrist flexor spasticity and hemiplegic wrist posture can cause explicit morphological changes in the CT and median nerve albeit normal findings on NCS., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The radial artery usually passes on the radial side of the wrist lateral to the wrist to enter the anatomical snuff box and dorsum of the hand. If the radial artery passes anterior to the wrist, it usually enters the carpal tunnel, and in such cases, it may lead to the compression of the median nerve within the carpal tunnel. During the routine dissection, we found a case of the unusual radial arterial branch that passed anterior to the wrist yet outside the carpal tunnel. The artery passed within a tunnel formed by the fibromuscular fibers of thenar muscles arising from the anterior aspect of the transverse carpal ligament. Knowledge of the course and distribution of the variant superficial palmar branch of radial artery are of importance to the surgeons operating around the wrist, radiologist interpreting angiograms, and orthopedists managing trauma to the wrist.

Background: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, which results from median nerve compression. A lot of nonsurgical modalities are available for the management of mild to moderate situations. Local Hyalase hydrodissection (HD) of the entrapped median nerve could offer a desirable sustained symptom alleviation., Objectives: To evaluate the clinical efficacy of Hyalase/saline solution carpal tunnel HD on pain, functional status, and nerve conduction in patients with CTS., Study Design: A randomized, double-blinded trial., Setting: Anesthesia, pain, and rheumatology clinics in a university hospital., Methods: Patients: 60 patients with CTS (> 6 months' duration)., Intervention: patients were allocated equally into either group 1 (HD with Hyalase + 10 mL saline solution injection), or group 2 (HD with 10 mL saline solution only)., Measurements: assessment of pain using Visual Analog Scale (VAS), functional disability (FD) score, and nerve conduction studies before injection, and over 6 months after injection. Nerve conduction parameters before injection and postinjection by the end of 3 and 6 months were evaluated as well., Results: Statistically significant lower postinjection values of VAS (1 ± 1.8, 2 ± 1.1, 2 ± 1.2, 2 ± 1.1) in group 1 versus (2 ± 1.2, 3 ± 1.7, 4 ± 1.5, 5 ± 2.6) in group 2 by the end of the first week, and the first, third, and sixth months, and significantly lower FD scores (15.3 ± 1.2, 13 ± 1.3, 10.2 ± 1.3, 10.2 ± 1.3) in group 1 versus (17.5 ± 1.8, 16.6 ± 2.8, 19.4 ± 3.2, 21.2 ± 2.5) in group 2 during the same time intervals. Nerve conduction study parameters have shown significantly higher velocity and lower latency in the Hyalase group than in the saline solution group by the 3 and 6 month follow-up., Limitation: We suggest a longer period could be reasonable., Conclusions: Carpal tunnel HD with Hyalase with saline solution is considered as an efficient technique offering a rapid onset of pain relief and functional improvements, and better median nerve conduction in patients with CTS over 6 months follow-up duration., Key Words: Carpal tunnel syndrome, Hyalase, median nerve hydrodissection.

Background: Corticosteroid injection into the carpal tunnel is both a diagnostic test and a therapeutic modality in the treatment of carpal tunnel syndrome. Many injection techniques are described in the literature. Improper placement of injection may result in damage to neurovascular structures in the carpal canal or decrease efficacy of the test and/or therapy. The purpose of this study is to determine if carpal tunnel injection using anatomic landmarks is reproducible and safe. A review of the senior author's injection technique is presented. Methods: Over 8 years, there were 756 attempted placements of a 25-gauge needle into the carpal tunnel in a simulated carpal tunnel injection prior to open carpal tunnel release. The needle was inserted at the wrist crease, just ulnar to palmaris longus. Open carpal tunnel release was subsequently performed, and position of the needle was recorded. Results: In 572 patients (75.7%), the needle was found to be in the carpal tunnel without penetration of contents. The needle was in the carpal tunnel but piercing the median nerve in 66 attempts (8.7%). The carpal tunnel was missed in 118 attempts (15.6%). Conclusions: This is the largest study looking at accuracy of carpal tunnel injection using anatomic landmarks. Our injection accuracy (75.7%) is less than reported in previous studies, which note 82% to 100% accuracy using the same injection technique. This may indicate that carpal tunnel injection is less reliable than previously thought. Safety of carpal tunnel injection remains an important concern. The median nerve was penetrated in 8.7% of attempts.

Background: Several anatomical variations of the median nerve recurrent motor branch have been described. No previous reports have described the anatomical variation of the ulnar nerve with respect to transverse carpal ligament. In this article, we present a patient with symptomatic compression of the ulnar nerve found to occur outside the Guyon canal due to a transligamentous course through the distal transverse carpal ligament. Methods: A 59-year-old, right-hand-dominant male patient presented with right hand pain, subjective weakness, and numbness in both the ulnar and the median nerve distributions. Electromyography revealed moderate demyelinating sensorimotor median neuropathy at the wrist and distal ulnar sensory neuropathy. At the time of planned carpal tunnel and Guyon canal release, a transligamentous ulnar nerve sensory common branch to the fourth webspace was encountered and safely released. Results: There were no surgical complications. The patient's symptoms of numbness in the median and ulnar nerve distribution clinically improved at his first postoperative visit. Conclusions: We have identified a case of transligamentous ulnar nerve sensory branch encountered during carpal tunnel release. To our knowledge, this has not been previously reported. While the incidence of this variant is unknown, hand surgeons should be aware of this anatomical variant as its location puts it at risk of iatrogenic injury during open and endoscopic carpal tunnel release.

Introduction: Inflammatory arthritis frequently affects the wrist, resulting in pain and disability. This study aims to investigate the long-term outcome of patients who underwent posterior interosseous nerve (PIN) denervation for inflammatory arthritis of the wrist., Method: xForty consecutive wrists (36 patients) treated with PIN denervation were identified (mean follow-up 47 months; mean age 62.6 years, 77.5% female). Pain and function scores were objectively measured using the patient-rated wrist-evaluation (PRWE) questionnaires. Data was compared for pre-operation and post-operation (early and long term). The Student's t test was used to compare differences between groups for continuous data, whilst the sign test was utilised for pairwise comparisons. The p value was set at 0.05 for all comparisons., Results: Three patients died during the course of this study from causes unrelated to wrist surgery, resulting in 93% follow-up. PRWE questionnaires demonstrated a significant improvement following PIN denervation (median pain pre-op 42 vs post-op 16 (p < 0.001); median function pre-op 82 vs post-op 41 (p < 0.001), respectively). There were no differences identified between early and long-term post-operative scores. Four cases (10%) had persistent, ulnar-based pain and required secondary salvage wrist arthrodesis. However, 95% of patients remained "very satisfied" or "satisfied" after surgery., Conclusions: This study highlights the effectiveness of PIN denervation as a simple alternative to wrist arthrodesis due to long-term improvement in pain and preservation of function. We recommend this procedure in the presence of a positive diagnostic PIN infiltration test to avoid wrist arthrodesis for as long as possible. In patients with predominantly ulnar-based wrist pain, the outcome is less predictable and this subgroup of patients should be counselled about the possibility of subsequent salvage wrist fusion. Key Points • One of the largest study cohorts which report on the outcome of the wrist PIN denervation procedure with over 2-year follow-up • Clinical outcomes of success are enhanced with the use of validated, objective patient-reported outcome measures relating to overall satisfaction, pain relief and function. • Long-term outcomes are compared to pre-operative and immediate post-operative outcome scores, demonstrating the benefits of PIN denervation and the longevity it provides.

Background: Ultrasound (US) measurement of cross-sectional area (CSA) of the median nerve has emerged as a viable alternative to electromyography/nerve conduction studies (EMG/NCS) for diagnosis of carpal tunnel syndrome (CTS). The purpose of this study is to compare CSA of the median nerve between US and MRI using current MRI and US technology. The null hypothesis is there is no difference between US and MRI CSA measurements. Methods : The study design was an observational cohort, enrolling patients presenting to clinic with MRI of the wrist. Participants with clinical signs and symptoms of CTS were excluded. The CSA measurements of the median nerve on MRI T1-weighted axial images were performed by a hand fellow blinded to results of US measurements, and US measurement of median nerve CSA was performed by a hand fellowship trained surgeon blinded to results of the MRI measurements. Results were analyzed via percent error, Pearson correlation, and t tests. Results: Twenty participants were enrolled with mean age of 29.4 years. Four left wrists and 16 right wrists were measured. The US mean CSA of the median nerve was 6.8 mm 2 (±2.330 mm 2 ). The MRI mean CSA of the median nerve was 6.8 mm 2 (±2.153 mm 2 ), P = .442. Pearson correlation between modalities was 0.93, suggesting near-perfect correlation. Mean percent error was 8.8%. Conclusions : Results of this study suggest that US is an accurate method to measure CSA of the median nerve at the carpal tunnel inlet. The mean difference between US and MRI was unlikely to be clinically significant.

A 55-year-old woman presented with an 18-month history of intermittent left-hand paresthesias affecting her first, second, and third digits. A small, immobile, nontender midline mass on the volar aspect of the left wrist was also present. Evaluation included normal routine nerve conduction studies and needle electromyography. An ultrasound was performed in the electromyography laboratory, verifying median nerve involvement of the mass within the proximal carpal tunnel. This finding guided the electromyographer to perform the unconventional technique of sensory nerve short segmental stimulation across the carpal tunnel, which confirmed focal slowing across the lesion, achieving electrodiagnostic confirmation of median nerve impairment. This case of atypical carpal tunnel syndrome due to a median nerve schwannoma demonstrates both the utility and specificity of short segmental sensory stimulation in some cases of median neuropathy at the wrist and the value of sonography in the electromyography laboratory.

Background: This study reviews long-term outcomes of partial wrist denervation focusing on need for and time to revision procedure. Methods: A retrospective study was conducted of all patients undergoing partial wrist denervation between 1994 and 2014. At average latest follow-up of 6.75 years (range, 1-21 years), clinical and radiographic data and need for revision surgery were recorded. Results: There were 100 wrists in 89 patients (61 male, 28 female) with average age at surgery of 54 years (range, 26-80). Principal diagnoses were arthritis (58%), inflammatory (19%), and posttraumatic arthritis (7%). Average flexion-extension arc was 83% and grip strength 75% of unaffected extremity. Average Mayo Wrist Scores improved from 48 preoperatively to 77 postoperatively. Sixty-nine percent of patients did not undergo other procedures during the time interval studied. Thirty-one percent underwent revision at an average of 26 months following denervation (range, 2-165). Conclusions: Partial wrist denervation is a motion-preserving procedure for patients with refractory wrist pain with 69% in this series requiring no further procedures. The remaining 31% experienced average symptom relief for 2 years prior to ultimately undergoing revision operation.

Purpose of Review: Carpal tunnel syndrome (CTS) is an entrapment neuropathy that involves the compression of the median nerve at the wrist and is considered the most common of all focal entrapment mononeuropathies. CTS makes up 90% of all entrapment neuropathies diagnosed in the USA and affects millions of Americans., Recent Findings: Age and gender likely play a role in the development of CTS, but additional studies may further elucidate these associations. Of known associated risk factors, diabetes mellitus seems to have the greatest association with CTS. One of the most commonly reported symptoms in CTS is a "pins-and-needles" sensation in the first three fingers and nocturnal burning pain that is relieved with activity upon waking. Treatment for CTS is variable depending on the severity of symptoms. Conservative management of CTS is usually considered first-line therapy. In cases of severe sensory or motor deficit, injection therapy or ultimately surgery may then be considered. Still CTS is often difficult to treat and may be reoccurring. Novel treatment modalities such as laser and shockwave therapy have demonstrated variable efficacy though further studies are needed to assess for safety and effect. Given the unknown and potentially complex etiology of CTS, further studies are needed to explore combinations of diagnostic and therapeutic modalities.

Objective: To evaluate the safety and effectiveness of a wrist-worn peripheral nerve stimulation device in patients with essential tremor (ET) in a single in-office session., Methods: This was a randomized controlled study of 77 ET patients who received either treatment stimulation (N = 40) or sham stimulation (N = 37) on the wrist of the hand with more severe tremor. Tremor was evaluated before and immediately after the end of a single 40-minute stimulation session. The primary endpoint compared spiral drawing in the stimulated hand using the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) Archimedes spiral scores in treatment and sham groups. Additional endpoints included TETRAS upper limb tremor scores, subject-rated tasks from the Bain and Findley activities of daily living (ADL) scale before and after stimulation as well as clinical global impression-improvement (CGI-I) rating after stimulation., Results: Subjects who received peripheral nerve stimulation did not show significantly larger improvement in the Archimedes spiral task compared to sham but did show significantly greater improvement in upper limb TETRAS tremor scores (p = 0.017) compared to sham. Subject-rated improvements in ADLs were significantly greater with treatment (49% reduction) than with sham (27% reduction; p = 0.001). A greater percentage of ET patients (88%) reported improvement in the stimulation group as compared to the sham group (62%) according to CGI-I ratings (p = 0.019). No significant adverse events were reported; 3% of subjects experienced mild adverse events., Conclusions: Peripheral nerve stimulation in ET may provide a safe, well-tolerated, and effective treatment for transient relief of hand tremor symptoms., (© 2019 The Authors. Neuromodulation: Technology at the Neural Interface published by Wiley Periodicals, Inc. on behalf of International Neuromodulation Society.)

Wearable automated seizure detection devices offer a high potential to improve seizure management, through continuous ambulatory monitoring, accurate seizure counts, and real-time alerts for prompt intervention. More importantly, these devices can be a life-saving help for people with a higher risk of sudden unexpected death in epilepsy (SUDEP), especially in case of generalized tonic-clonic seizures (GTCS). The Embrace and E4 wristbands (Empatica) are the first commercially available multimodal wristbands that were designed to sense the physiological hallmarks of ongoing GTCS: while Embrace only embeds a machine learning-based detection algorithm, both E4 and Embrace devices are equipped with motion (accelerometers, ACC) and electrodermal activity (EDA) sensors and both the devices received medical clearance (E4 from EU CE, Embrace from EU CE and US FDA). The aim of this contribution is to provide updated evidence of the effectiveness of GTCS detection and monitoring relying on the combination of ACM and EDA sensors. A machine learning algorithm able to recognize ACC and EDA signatures of GTCS-like events has been developed on E4 data, labeled using gold-standard video-EEG examined by epileptologists in clinical centers, and has undergone continuous improvement. While keeping an elevated sensitivity to GTCS (92-100%), algorithm improvements and growing data availability led to lower false alarm rate (FAR) from the initial ˜2 down to 0.2-1 false alarms per day, as showed by retrospective and prospective analyses in inpatient settings. Algorithm adjustment to better discriminate real-life physical activities from GTCS, has brought the initial FAR of ˜6 on outpatient real life settings, down to values comparable to best-case clinical settings (FAR < 0.5), with comparable sensitivity. Moreover, using multimodal sensing, it has been possible not only to detect GTCS but also to quantify seizure-induced autonomic dysfunction, based on automatic features of abnormal motion and EDA. The latter biosignal correlates with the duration of post-ictal generalized EEG suppression, a biomarker observed in 100% of monitored SUDEP cases., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: To analyze the anatomical variations of the innervation of the flexor digitorum superficialis muscle and to determine if the branch of the median nerve that supply this muscle is connected to the branches to the extensor carpi radialis brevis and the pronator teres muscles, without tension, and how close to the target-muscles the transfer can be performed., Methods: Fifty limbs of 25 cadavers were dissected to collect data on the anatomical variations of the branches to the flexor digitorum superficialis muscle., Results: This muscle received innervation from the median nerve in the 50 limbs. In 22 it received one branch, and in 28 more than one. The proximal branch was identified in 22 limbs, and in 12 limbs it shared branches with other muscles. The distal branch was present in all, and originated from the median nerve as an isolated branch, or a common trunk with the anterior interosseous nerve in 3 limbs, and from a common trunk with the flexor carpi radialis muscle and anterior interosseous nerve in another. It originated distally to the anterior interosseous nerve at 38, in 5 on the same level, and in 3 proximal to the anterior interosseous nerve. In four limbs, innervation came from the anterior interosseous nerve, as well as from the median nerve. Accessory branches of the median nerve for the distal portion of the flexor digitorum superficialis muscle were present in eight limbs., Conclusion: In 28 limbs with two or more branches, one of them could be connected to the branches to the extensor carpi radialis brevis and pronator teres muscles without tension, even during the pronation and supination movements of the forearm and flexion-extension of the elbow.

Sensorimotor function is a fundamental brain function in humans, and the cerebrocerebellar circuit is essential to this function. In this study, we demonstrate how the cerebrocerebellar circuit develops both functionally and anatomically from childhood to adulthood in the typically developing human brain. We measured brain activity using functional magnetic resonance imaging while a total of 57 right-handed, blindfolded, healthy children (aged 8-11 years), adolescents (aged 12-15 years), and young adults (aged 18-23 years) (n = 19 per group) performed alternating extension-flexion movements of their right wrists in precise synchronization with 1-Hz audio tones. We also collected their diffusion MR images to examine the extent of fiber maturity in cerebrocerebellar afferent and efferent tracts by evaluating the anisotropy-sensitive index of hindrance modulated orientational anisotropy (HMOA). During the motor task, although the ipsilateral cerebellum and the contralateral primary sensorimotor cortices were consistently activated across all age groups, the functional connectivity between these two distant regions was stronger in adults than in children and adolescents, whereas connectivity within the local cerebellum was stronger in children and adolescents than in adults. The HMOA values in cerebrocerebellar afferent and efferent tracts were higher in adults than in children (some were also higher than in adolescents). The results indicate that adult-like cerebrocerebellar functional coupling is not completely achieved during childhood and adolescence, even for fundamental sensorimotor brain function, probably due to anatomical immaturity of cerebrocerebellar tracts. This study clearly demonstrated the principle of "local-to-distant" development of functional brain networks in the human cerebrocerebellar sensorimotor network.

Purpose: We compared the modulation of force steadiness by different types of electrical nerve stimulation in young (n = 13, 25 ± 4 years) and older (n = 12, 78 ± 5 years) adults., Methods: The protocol involved four types of isometric contractions with the wrist-extensor muscles at 10% of the maximal force. Three of the contractions involved electrical nerve stimulation that comprised two forms of neuromuscular electrical stimulation (NMES) to evoke muscle contractions and a voluntary contraction with superimposed transcutaneous electrical nerve stimulation (TENS) at an intensity less than motor threshold., Results: The coefficient of variation (CV) for force during voluntary wrist extension was less (P = 0.03) for young (1.82 ± 0.43%) than older adults (2.80 ± 1.08%). The CV for force did not differ between age groups during the three types of electrical nerve stimulation but was reduced relative to the value observed during voluntary wrist extension for older adults. In contrast, the CV for force increased during the voluntary contraction with superimposed TENS for young adults but not for older adults. Moreover, there were significant negative correlations in older adults between the CV for force during the voluntary contraction and its decrease with electrical nerve stimulation., Conclusion: Differences in the CV for force between the evoked and voluntary contractions for the two age groups suggest that the variance in common synaptic input to motor neurons during steady voluntary contractions with the wrist extensors is greater for older adults than young adults.

Introduction: Patients presenting with symptoms of pain/paresthesias primarily in an ulnar nerve distribution may be noted to have exclusive median mononeuropathy at the wrist on subsequent electrodiagnostic testing. There has been limited research looking at the prevalence of this clinical presentation., Methods: A cohort of adults were surveyed to assess for severity and localization of hand symptoms using the Katz hand diagram and Boston Carpal Tunnel Questionnaire Symptoms Severity Scale. Thirty volunteers met our case definition for ulnar neuropathy and underwent a standardized physical examination, electrodiagnostic testing, and nerve ultrasound., Results: Eleven of 30 subjects (37%) were found to have exclusive median mononeuropathy at the wrist., Discussion: Carpal tunnel syndrome should remain high on the differential for patients presenting with symptoms of pain/paresthesias primarily in an ulnar nerve distribution. Muscle Nerve 59:60-63, 2019., (© 2018 Wiley Periodicals, Inc.)

Introduction: Routine ulnar nerve conduction studies may be normal in very mild ulnar neuropathies at the elbow (UNE). Short segment ulnar sensory stimulation across the elbow may detect mild abnormalities in these cases., Methods: Short segment ulnar sensory nerve stimulation was performed in 20 controls and 15 patients with clinically suspected mild UNE. Greatest peak latency shift and amplitude drop between 2 adjacent stimulation sites were calculated., Results: The upper limit of normal for peak latency shift and amplitude reduction between sites was 0.7 ms and 15%, respectively. Abnormal latency shift was detected in 12 of 15 patients and focal sensory conduction block in 6 of 15 patients. In 5 of 7 patients in whom all other studies were normal, sensory inching was abnormal., Discussion: Ulnar sensory short segment stimulation may provide diagnostic confirmation and localization of the site of nerve compression in mild UNE, and may improve UNE detection when all other studies are normal. Muscle Nerve 59:125-129, 2019., (© 2018 Wiley Periodicals, Inc.)

Introduction: This study explored potential diagnostic markers of nerve ultrasound in differentiating amyotrophic lateral sclerosis (ALS) from mimic disorders., Methods: Ultrasound of the median, ulnar, and tibial nerves was conducted in 53 patients with ALS, 32 patients with ALS-mimic disorders, and 30 controls. Nerve cross-sectional area (CSA) and distal-proximal ratios were calculated., Results: The median nerve CSA in the upper arm was decreased (7.9 ± 1.3 mm 2 vs. 9.0 ± 1.4 mm 2 , P < 0.05), and the median nerve wrist-upper arm ratio was increased in ALS patients compared with controls (1.3 ± 0.4 vs. 1.1 ± 0.2; P < 0.01). In differentiating ALS from mimic presentations, assessment of median nerve CSA in the upper arm and comparison of a median and ulnar nerve CSA distal-proximal ratio provide diagnostic potential., Discussion: Assessment of nerve CSA combined with calculation of nerve CSA distal-proximal ratio provides a useful marker to aid in the diagnosis of ALS. Muscle Nerve 58:777-783, 2018., (© 2018 Wiley Periodicals, Inc.)

We describe a patient with pseudoradial nerve palsy caused by acute ischaemic stroke ('cortical hand') to emphasise how preserved synkinetic wrist extension following fist closure can distinguish this from peripheral causes of wrist drop., Competing Interests: Competing interests: FB has received speakers' honoraria from Eisai and PeerVoice, payment for consultancy from Eisai, and travel support from Eisai, ITALFARMACO and UCB Pharma., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Impaired corticomotor function is reported in patients with lateral epicondylalgia, but the causal link to pain or musculotendinous overloading is unclear. In this study, sensorimotor cortical changes were investigated using a model of persistent pain combined with an overloading condition. In 24 healthy subjects, the effect of nerve growth factor (NGF)-induced pain, combined with delayed-onset muscle soreness (DOMS), was examined on pain perception, pressure pain sensitivity, maximal force, and sensorimotor cortical excitability. Two groups (NGF alone and NGF + DOMS) received injections of NGF into the extensor carpi radialis brevis (ECRB) muscle at day 0, day 2, and day 4. At day 4, the NGF + DOMS group undertook wrist eccentric exercise to induce DOMS in the ECRB muscle. Muscle soreness scores, pressure pain thresholds over the ECRB muscle, maximal grip force, transcranial magnetic stimulation mapping of the cortical ECRB muscle representation, and somatosensory-evoked potentials from radial nerve stimulation were recorded at day 0, day 4, and day 6. Compared with day 0, day 4 showed in both groups: (1) increased muscle soreness (P < 0.01); (2) reduced pressure pain thresholds (P < 0.01); (3) increased motor map volume (P < 0.01); and (4) decreased frontal N30 somatosensory-evoked potential. At day 6, compared with day 4, only the DOMS + NGF group showed: (1) increased muscle soreness score (P < 0.01); (2) decreased grip force (P < 0.01); and (3) decreased motor map volume (P < 0.05). The NGF group did not show any difference on the remaining outcomes from day 4 to day 6. These data suggest that sustained muscle pain modulates sensorimotor cortical excitability and that exercise-induced DOMS alters pain-related corticomotor adaptation.

OBJECTIVEContralateral C7 (CC7) nerve root has been used as a donor nerve for targeted neurotization in the treatment of total brachial plexus palsy (TBPP). The authors aimed to study the contribution of C7 to the innervation of specific upper-limb muscles and to explore the utility of C7 nerve root as a recipient nerve in the management of TBPP.METHODSThis was a 2-part investigation. 1) Anatomical study: the C7 nerve root was dissected and its individual branches were traced to the muscles in 5 embalmed adult cadavers bilaterally. 2) Clinical series: 6 patients with TBPP underwent CC7 nerve transfer to the middle trunk of the injured side. Outcomes were evaluated with the modified Medical Research Council scale and electromyography studies.RESULTSIn the anatomical study there were consistent and predominantly C7-derived nerve fibers in the lateral pectoral, thoracodorsal, and radial nerves. There was a minor contribution from C7 to the long thoracic nerve. The average distance from the C7 nerve root to the lateral pectoral nerve entry point of the pectoralis major was the shortest, at 10.3 ± 1.4 cm. In the clinical series the patients had been followed for a mean time of 30.8 ± 5.3 months postoperatively. At the latest follow-up, 5 of 6 patients regained M3 or higher power for shoulder adduction and elbow extension. Two patients regained M3 wrist extension. All regained some wrist and finger extension, but muscle strength was poor. Compound muscle action potentials were recorded from the pectoralis major at a mean follow-up of 6.7 ± 0.8 months; from the latissimus dorsi at 9.3 ± 1.4 months; from the triceps at 11.5 ± 1.4 months; from the wrist extensors at 17.2 ± 1.5 months; from the flexor carpi radialis at 17.0 ± 1.1 months; and from the digital extensors at 22.8 ± 2.0 months. The average sensory recovery of the index finger was S2. Transient paresthesia in the hand on the donor side, which resolved within 6 months postoperatively, was reported by all patients.CONCLUSIONSThe C7 nerve root contributes consistently to the lateral pectoral nerve, the thoracodorsal nerve, and long head of the triceps branch of the radial nerve. CC7 to C7 nerve transfer is a reconstructive option in the overall management plan for TBPP. It was safe and effective in restoring shoulder adduction and elbow extension in this patient series. However, recoveries of wrist and finger extensions are poor.

The superficial palmar branch (SPB) of the radial artery (RA) is an important blood vessel in plastic surgery procedures of the hand. It is used as the axial artery in a free flap used for finger reconstruction. The occurrence of this arterial branch is variable, as well as its diameter and course. The aim of this study was to determine the occurrence and measure the external diameter of the SPB, as well as the external circumference of the RA. All results were analyzed with the intent to determine a possible correlation between RA and SPB size, as well as between SPB occurrence and the cadavers' sex and height. The study was conducted on both upper extremities of 60 cadavers (31 male and 29 female), of 35-55 years of age (average age was 46.5 years). A radial artery sample was taken at the level of the wrist, together with its superficial palmar branch. The samples were preserved in 4% formaldehyde for four weeks. After the fixation, the external circumference of the radial artery and the external diameter of the superficial palmar branch were measured with a Vernier caliper and an operating microscope. Bilateral SPB absence was the most common variant of SPB occurrence in our material. There was no linear correlation between the size of the RA and the SPB, nor was there any relationship between SPB occurrence and the cadavers' age and height. Also, the correlation between the cadavers' height and the size of both blood vessels was not linear. We conclude that the SPB diameter and occurrence are independent of the other factors described in this study., (Copyright © 2018 Elsevier GmbH. All rights reserved.)