Nerve Fascicles Research Articles

Dermal Sensory Regenerative Peripheral Nerve Interface for Reestablishing Sensory Nerve Feedback in Peripheral Afferents in the Rat.

Without meaningful, intuitive sensory feedback, even the most advanced myoelectric devices require significant cognitive demand to control. The dermal sensory regenerative peripheral nerve interface (DS-RPNI) is a biological interface designed to establish high-fidelity sensory feedback from prosthetic limbs. DS-RPNIs were constructed in rats by securing fascicles of residual sensory peripheral nerves into autologous dermal grafts, with the objectives of confirming regeneration of sensory afferents within DS-RPNIs and establishing the reliability of afferent neural response generation with either mechanical or electrical stimulation. Two months after implantation, DS-RPNIs were healthy and displayed well-vascularized dermis with organized axonal collaterals throughout and no evidence of neuroma. Electrophysiologic signals were recorded proximal from DS-RPNI's sural nerve in response to both mechanical and electrical stimuli and compared with (1) full-thickness skin, (2) deepithelialized skin, and (3) transected sural nerves without DS-RPNI. Mechanical indentation of DS-RPNIs evoked compound sensory nerve action potentials (CSNAPs) that were like those evoked during indentation of full-thickness skin. CSNAP firing rates and waveform amplitudes increased in a graded fashion with increased mechanical indentation. Electrical stimuli delivered to DS-RPNIs reliably elicited CSNAPs at low current thresholds, and CSNAPs gradually increased in amplitude with increasing stimulation current. These findings suggest that afferent nerve fibers successfully reinnervate DS-RPNIs, and that graded stimuli applied to DS-RPNIs produce proximal sensory afferent responses similar to those evoked from normal skin. This confirmation of graded afferent signal transduction through DS-RPNI neural interfaces validate DS-RPNI's potential role of facilitating sensation in human-machine interfacing. The DS-RPNI is a novel biotic-abiotic neural interface that allows for transduction of sensory stimuli into neural signals. It is expected to advance the restoration of natural sensation and development of sensorimotor control in prosthetics.

The role of ultrasonography in diagnosis of neuralgic amyotrophy.

To investigate the value of high frequency ultrasound in diagnosis of neuralgic amyotrophy. From January 2010 to December 2020, the ultrasonographic images of 117 patients with neuralgic amyotrophy diagnosed by the Department of Neurology and hand & foot surgery of Shandong Provincial Hospital Affiliated to Shandong First Medical University were retrospectively analyzed. The ultrasonographic features were summarized. High frequency ultrasound could clearly show the degree of the affected nerves: No ultrasonic findings were found in 12 cases (10%). The affected nerves were thickening and hypoechogenicity with loss of normal fascicular definition in 28 cases (24%). The affected nerves showed hourglass-like changes, including constriction and torsion in 77 cases (66%). In addition, ultrasound can determine the extent of the lesion, and microvascular imaging can display small blood flow signal within the nerve. There was a significant statistical difference between the diameter of the thickened nerve fascicle and the diameter of the nerve fascicle at the corresponding site of the contralateral normal limb. High frequency ultrasound is a valuable imaging method for diagnosis of neuralgic amyotrophy.

Derivation of a bidomain model for bundles of myelinated axons

The work concerns the multiscale modeling of a nerve fascicle of myelinated axons. We present a rigorous derivation of a macroscopic bidomain model describing the behavior of the electric potential in the fascicle based on the FitzHugh–Nagumo membrane dynamics. The approach is based on the two-scale convergence machinery combined with the method of monotone operators.

Targeted NAC Reinnervation (TNR) with Nerve Fascicle Split in Implant Based Breast Reconstruction

Targeted NAC Reinnervation (TNR) with Nerve Fascicle Split in Implant Based Breast Reconstruction

Structure and barrier functions of the perineurium and its relationship with associated sensory corpuscles: A review.

Peripheral nerves are provided with a blood-nerve barrier which prevents the invasion of harmful substances and pathogens, and also regulates metabolic and ionic homeostasis within nerve fascicles. The barrier functions are attributed to both the concentric layer of flattened cells in the perineurium and blood vessels running in the endoneurium. The perineurial cells develop continuous tight junctions as a diffusion barrier. In order to take up a predominant nutrient, glucose, the perineurium as well as endoneurial capillaries expresses GLUT1, a glucose transporter. An axon-Schwann cell complex within peripheral nerves utilizes glucose as a major energy source via the GLUT1, as does the brain. Under conditions of a reduced utilization of glucose, only the perineurial cells can transfer other nutrients, namely monocarboxylates such as ketone bodies and lactate via MCT1. Thus, MCT1 colocalizes with GLUT1 in the perineurium but not in endoneurial capillaries. To identify the cellular origins of the nerve sheath, marker proteins such as glial specific S100 protein, GLUT1, endoneurial CD34, and EMA (epithelial membrane antigen) are useful. Immunohistochemical findings for these markers are reviewed in this paper, focusing on the perineurium and endoneurium and their derivatives, Pacinian and Meissner corpuscles. Growing evidence throws light on the critical involvement of the nerve sheaths in the development, maintenance, and diseases of peripheral nerves.

Fluorescein-Assisted Microsurgical Resection of Vestibular Schwannoma: A Prospective Feasibility Study.

To evaluate the optimal dose and timing of administration of sodium fluorescein (SF) for selective fluorescence of sporadic vestibular schwannoma (VS) during microsurgery with the YELLOW 560-nm microscope filter (YE560) and to characterize the potential benefit of this fluorescence as determined by intraoperative surgeon assessment. Prospective cohort study. Tertiary referral center. Adult patients undergoing VS microsurgery. Intraoperative intravenous administration of SF and visualization with the YE560. Time to differential fluorescence, duration of fluorescence, correlation of fluorescence of VS with electrostimulation and white light microscopy visual assessment, and likelihood of surgeons to use SF with the YE560 in future cases. Novel use of SF and YE560 during microsurgery achieved selective fluorescence of VS with capabilities to differentiate nerve fascicles and tumor approximately 30 minutes after administration. Nuances of SF administration and timing are discussed. Seventy-five percent of surgeons observed an excellent correlation of selective fluorescence with white light microscopy. Representative images and cases are presented. SF and YE560 may be used in VS microsurgery to visually differentiate VS from surrounding nerves. Potential benefits include enhanced visualization of the tumor-nerve interface for tumor dissection and detection of any residual disease, such as in the fundus after hearing preservation microsurgery.

Activating effective functional hand movements in individuals with complete tetraplegia through neural stimulation

Individuals with complete cervical spinal cord injury suffer from a permanent paralysis of upper limbs which prevents them from achieving most of the activities of daily living. We developed a neuroprosthetic solution to restore hand motor function. Electrical stimulation of the radial and median nerves by means of two epineural electrodes enabled functional movements of paralyzed hands. We demonstrated in two participants with complete tetraplegia that selective stimulation of nerve fascicles by means of optimized spreading of the current over the active contacts of the multicontact epineural electrodes induced functional and powerful grasping movements which remained stable over the 28 days of implantation. We also showed that participants were able to trigger the activation of movements of their paralyzed limb using an intuitive interface controlled by voluntary actions and that they were able to perform useful functional movements such as holding a can and drinking through a straw.

Successful enucleation of a large sciatic schwannoma with intraoperative neurostimulation-guided dissection: a case report

Advances in intraoperative neurophysiological monitoring (IONM) have enabled safer peripheral nerve tumor surgery. We report a patient in whom a large sciatic nerve schwannoma was successfully removed using intraoperative nerve stimulation. A 62-year-old male presented with a palpable mass in the right posterior upper thigh, just below the gluteal fold. Magnetic resonance imaging showed an approximately 9-cm encapsulated solid mass in the middle of the sciatic nerve. After a vertical skin incision with a laterally curved upper end extending to the inferior gluteal region, the proximal sciatic nerve was secured laterally to the biceps femoris and the distal nerve medial to the muscle. We avoided causing trauma to the viable nerve fascicles by dissecting through the “safe zone,” as confirmed by monitoring the distal muscle contractions induced by intraoperative nerve stimulation on the tumor surface. In this report, we present the details of our surgical approach to the middle portion of the sciatic nerve and the use of IONM for safe tumor excision.

Surgical Treatment and Complications of Deep-Seated Nodular Plexiform Neurofibromas Associated with Neurofibromatosis Type 1.

Background: Nodular plexiform neurofibromas in individuals with neurofibromatosis type 1 often cause significant symptoms and are treated with surgical excision despite the potential risk of complications. This study aimed to clarify the surgical outcomes of deep-seated nodular plexiform neurofibromas and identify the factors associated with postoperative complications. Methods: We retrospectively reviewed patients with neurofibromatosis type 1 who underwent surgical excision for deep-seated nodular plexiform neurofibromas in our hospital from 2015 to 2021. Enucleation while preserving the nerve fascicles was attempted first, and en bloc resection, ligating the nerve origin in cases in which the parent nerve was entrapped by the tumor, making the tumor difficult to dissect, was performed. Results: In 15 patients, 24 nodular plexiform neurofibromas received surgical excision. Sixteen tumors were enucleated, and eight were en bloc resected. The symptoms of all 10 patients with preoperative symptoms resolved after surgery. Four patients developed new neurological deficits immediately after surgery, two of whom had retained neurological symptoms at the last visit, but these symptoms were mild. Conclusions: The present study demonstrates that surgical treatment of nodular plexiform neurofibromas, even deep-seated neurofibromas, is safe with a low risk of severe complications and improvement in preoperative symptoms.

Intracranial Facial Schwannomas: Multiple Distinct Entities Necessitating Tailored Management

Facial nerve (FN) schwannomas are extremely rare. According to their origin and involved segment(s), they constitute distinct subtypes. Intact FN function presents a management challenge, particularly in the cerebellopontine angle cisternal subtype that masquerades as a vestibular schwannoma. Fascicular-sparing technique with subtotal resection can maintain a good FN function. This study focuses on management to maintain good FN function. A retrospective analysis of a cohort of 13 patients harboring FN schwannoma. Patient demographics, clinical findings, imaging, surgical intervention, and outcomes were analyzed. Five women and 8 men, with an average age of 55.3 years (39-75 years), harbored 6 cisternal, 2 ganglion, and 5 combined tumors. Average tumor size was 28.3 mm (16-50 mm). Eleven patients underwent surgery. Seven patients had fascicle-sparing technique, 5 of whom maintained their preoperative FN function, whereas 2 patients with near-total removal had a deterioration in FN function. Two patients with preoperative complete facial paralysis had gross total removal with interposition nerve graft. FN schwannomas management is individualized according to the subtype and the FN function at presentation. When FN function is normal, observation can be applied for prolonged period of time. At the early sign of deterioration, sub- or near-total resection with fascicle sparing technique can be performed. The cisternal subtype masquerade as vestibular schwannoma and should be recognized at the initial exposure by the appearance of finely splayed nerve fascicles at the perimetry of the tumor which elicits a motor response at low threshold stimulation.

Mapping the functional anatomy and topography of the cardiac autonomic innervation for selective cardiac neuromodulation using MicroCT.

Background: Vagus nerve stimulation (VNS) has gained great importance as a promising therapy for a myriad of diseases. Of particular interest is the therapy of cardiovascular diseases, such as heart failure or atrial fibrillation using selective cardiac VNS. However, there is still a lack of organ-specific anatomical knowledge about the fascicular anatomy and topography of the cardiac branch (CB), which diminishes the therapeutic possibilities for selective cardiac neuromodulation. Here, we established a topographical and anatomical map of the superior cardiac VN in two animal species to dissect cervical and cardiac VN morphology. Methods: Autonomic nerves including superior CBs were harvested from domestic pigs and New Zeeland rabbits followed by imaging with microcomputed tomography (µCT) and 3D rendering. The data were analyzed in terms of relevant topographical and anatomical parameters. Results: Our data showed that cardiac vagal fascicles remained separated from other VN fascicles up to 22.19 mm (IQR 14.02–41.30 mm) in pigs and 7.68 mm (IQR 4.06–12.77 mm) in rabbits from the CB point and then started merging with other fascicles. Exchanges of nerve fascicles between sympathetic trunk (ST) and VN were observed in 3 out of 11 nerves, which might cause additional unwanted effects in unselective VNS. Our 3D rendered digital model of the cardiac fascicles was generated showing that CB first remained on the medial side where it branched off the VN, as also shown in the µCT data of 11 pig nerves, and then migrated towards the ventromedial site the further it was traced cranially. Conclusion: Our data provided an anatomical map of the cardiac vagal branches including cervical VN and ST for future approaches of selective cardiac neurostimulation, indicating the best position of selective cardiac VNS just above the CB point.

Surgical Treatment of Parsonage Turner Syndrome With Primary Nerve Transfers: A Case Series and Cadaver Dissection.

Parsonage Turner syndrome (PTS) is the development of severe, spontaneous pain with subsequent nerve palsy. Unfortunately, many patients never achieve full functional recovery, and many have chronic pain. The use of nerve transfers in PTS has not been reported in the literature. We present 4 cases of PTS treated surgically with primary nerve transfer and neurolysis of the affected nerve following the absence of clinical and electrodiagnostic recovery at 5 months from onset. In addition, we present a cadaver dissection demonstrating an interfascicular dissection of the anterior interosseous nerve (AIN) into its components to enable a fascicular transfer in partial AIN neuropathy. Two patients with complete axillary neuropathy underwent a neurorrhaphy between the nerve branch to the lateral head of the triceps and the anterior/middle deltoid nerve branch of the axillary nerve. Two patients with partial AIN neuropathy involving the FDP to the index finger (FDP2) underwent a neurorrhaphy between an extensor carpi radialis brevis nerve branch and the FDP2 nerve branch. All patients had neurolysis of the affected nerves. All subjects recovered at least M4 motor strength. The cadaver dissection demonstrates 3 separate nerve fascicles of the AIN into FPL, FDP2, and pronator quadratus that can be individually selected for reinnervation with a fascicular nerve transfer. Functional recovery for patients with PTS with neurolysis alone is variable. Surgical treatment with neurolysis and a nerve transfer to improve functional recovery when no recovery is seen by 5 months is an option.

Structure of the myenteric plexus in normal and diseased human ileum analyzed by X-ray virtual histology slices.

BACKGROUNDThe enteric nervous system (ENS) is situated along the entire gastrointestinal tract and is divided into myenteric and submucosal plexuses in the small and large intestines. The ENS consists of neurons, glial cells, and nerves assembled into ganglia, surrounded by telocytes, interstitial cells of Cajal, and connective tissue. Owing to the complex spatial organization of several interconnections with nerve fascicles, the ENS is difficult to examine in conventional histological sections of 3-5 μm.AIMTo examine human ileum full-thickness biopsies using X-ray phase-contrast nanotomography without prior staining to visualize the ENS.METHODSSix patients were diagnosed with gastrointestinal dysmotility and neuropathy based on routine clinical and histopathological examinations. As controls, full-thickness biopsies were collected from healthy resection ileal regions after hemicolectomy for right colon malignancy. From the paraffin blocks, 4-µm thick sections were prepared and stained with hematoxylin and eosin for localization of the myenteric ganglia under a light microscope. A 1-mm punch biopsy (up to 1 cm in length) centered on the myenteric plexus was taken and placed into a Kapton® tube for mounting in the subsequent investigation. X-ray phase-contrast tomography was performed using two custom-designed laboratory setups with micrometer resolution for overview scanning. Subsequently, selected regions of interest were scanned at a synchrotron-based end-station, and high-resolution slices were reported. In total, more than 6000 virtual slices were analyzed from nine samples.RESULTSIn the overview scans, the general architecture and quality of the samples were studied, and the myenteric plexus was localized. High-resolution scans revealed details, including the ganglia, interganglional nerve fascicles, and surrounding tissue. The ganglia were irregular in shape and contained neurons and glial cells. Spindle-shaped cells with very thin cellular projections could be observed on the surface of the ganglia, which appeared to build a network. In the patients, there were no alterations in the general architecture of the myenteric ganglia. Nevertheless, several pathological changes were observed, including vacuolar degeneration, autophagic activity, the appearance of sequestosomes, chromatolysis, and apoptosis. Furthermore, possible expulsion of pyknotic neurons and defects in the covering cellular network could be observed in serial slices. These changes partly corresponded to previous light microscopy findings.CONCLUSIONThe analysis of serial virtual slices could provide new information that cannot be obtained by classical light microscopy. The advantages, disadvantages, and future possibilities of this method are also discussed.

Mast Cell Population and Histamine Content in Hypothyroid Rat Tissues.

Simple SummaryIn this study, we investigated the putative regulatory role of the pituitary–thyroid axis on mast cells (MCs). We found that hypothyroidism resulted in a significant increase in number of MCs and the histamine content in the skin and exorbital lacrimal gland of Wistar rats, Rattus norvegicus. Furthermore, an increase in the percentage of degranulating MCs suggests that the thyroid status also influences the activation state of these cells.The morphological features and relative number of mast cells (MCs) were studied in the skin and exorbital lacrimal glands of hypothyroid Wistar rats, Rattus norvegicus. Hypothyroidism significantly increased the number of MCs (up to 4.5-fold) and histamine content (up to 50%) in the examined tissues. The magnitude of the increase in the number of MCs was greater in the cheek skin and exorbital lacrimal glands than in the back skin. In the skin, the MCs were mainly located within the hypodermis and closely associated with the blood vessels, nerve fascicles, and adipocytes. In the exorbital lacrimal gland, which is a seromucous gland located lateral to the cheek below the ear, the MCs were distributed in the connective tissue surrounding the acini. The secretory granules of MCs showed histochemical characteristics of connective tissue MCs. They were metachromatic with Toluidine blue and safranin positive with the Alcian blue/safranin reactions. Finally, a significant increase in degranulating MCs was observed in hypothyroid tissues, relative to euthyroid tissues. At the ultrastructural level, the MCs of euthyroid rats were predominantly non-degranulating (Stage I). In hypothyroid animals, numerous MCs showed partial degranulation (Stage II–III) or were in a stage of complete degranulation. Our results concerning the skin and exorbital lacrimal gland suggested that the thyroid status might be involved in regulating the frequency and activation state of MCs.

Comparison of the soleus and plantaris muscles in humans and other primates: Macroscopic neuromuscular anatomy and evolutionary significance.

In humans, the soleus is more developed compared to other primates and has a unique architecture composed of anterior bipennate and posterior unipennate parts, which are innervated by different nerve branches. The anterior part of the human soleus was proposed to be important for bipedalism, however, the phylogenetic process resulting in its acquisition remains unclear. Providing insights into this process, the anterior part of the soleus was suggested to be closely related to the plantaris based on the branching pattern of their nerve fascicles. To reveal the phylogeny of the soleus and plantaris in primates, the innervation patterns of the posterior crural muscles were compared among a wide range of species. From their branching pattern, posterior crural muscles could be classified into superficial and deep muscle groups. The anterior part of the soleus and plantaris both belonged to the deep muscle group. In all the examined specimens of ring-tailed lemurs and chimpanzees, as well as in one out of two specimens of siamang, the nerve branches corresponding to those innervating the anterior part of the human soleus were found. The muscular branches innervating the anterior part of the soleus and plantaris formed a common trunk or were connected in all the specimens. These results indicate that the anterior part of the soleus is closely related to the plantaris across different species of primates. In turn, this suggests that the anterior part of the soleus is maintained among primates, and especially in humans, where it develops as the characteristic bipennate structure.

Feasibility of simultaneous high-resolution anatomical and quantitative magnetic resonance imaging of sciatic nerves in patients with Charcot-Marie-Tooth type 1A (CMT1A) at 7T.

Magnetic resonance imaging (MRI) of peripheral nerves can provide image-based anatomical information and quantitative measurement. The aim of this pilot study was to investigate the feasibility of high-resolution anatomical and quantitative MRI assessment of sciatic nerve fascicles in patients with Charcot-Marie-Tooth (CMT) 1A using 7T field strength. Six patients with CMT1A underwent imaging on a high-gradient 7T MRI scanner using a 28-channel knee coil. Two high-resolution axial images were simultaneously acquired using a quantitative double-echo in steady-state (DESS) sequence. By comparing the two DESS echoes, T2 and apparent diffusion coefficient (ADC) maps were calculated. The cross-sectional areas and mean T2 and ADC were measured in individual fascicles of the tibial and fibular (peroneal) portions of the sciatic nerve at its bifurcation and 10 mm distally. Disease severity was measured using Charcot-Marie-Tooth Examination Score (CMTES) version 2 and compared to imaging findings. We demonstrated the feasibility of 7T MRI of the proximal sciatic nerve in patients with CMT1A. Using the higher field, it was possible to measure individual bundles in the tibial and fibular divisions of the sciatic nerve. There was no apparent correlation between diffusion measures and disease severity in this small cohort. This pilot study indicated that high-resolution MRI that allows for combined anatomical and quantitative imaging in one scan is feasible at 7T field strengths and can be used to investigate the microstructure of individual nerve fascicles.

The Demography of Traumatic Brachial Plexus Avulsion Injuries.

Background and objectiveBrachial plexus injuries more commonly affect the younger generation who constitute the productive workforce. The patients who sustain avulsion injuries of the brachial plexus are more often involved in high-velocity accidents. The avulsion injuries are surgically managed by nerve transfers. This study aimed to evaluate the demography of brachial plexus avulsion injuries.Materials and methodsThis retrospective study was conducted in January 2013 and included 21 patients treated from January 2007 to December 2011.ResultsOf the 21 patients, 20 were male and the most commonly affected patients were in the age group of 21-30 years. The mean age of the affected patients was 27.24 years. Six of the patients had pan palsy (C5-8 and T1), nine had C5-7 injury, and six had C5-6 injury. Twenty patients underwent spinal accessory to suprascapular nerve transfer, nine patients underwent ulnar nerve fascicle to nerve to biceps branch transfer, and one patient underwent intercostal nerve to musculocutaneous nerve transfer. Of note, 40% of the patients regained more than M3 power for abduction and external rotation of the shoulder, and 30% of the patients regained more than M3 power for elbow function.ConclusionsRoad traffic accidents are the most common cause of brachial plexus injuries. Nerve transfers for shoulder and elbow function play a significant role in improving the function of the upper extremity.

Procedural Approach to Ultrasound-Guided Geniculate Nerve Blockade for Knee Pain in Patients with OA.

Ultrasound-guided genicular nerve block can provide excellent pain control for patients with knee OA. This procedure has the advantage of providing sensory blockade with concomitant sparing of motor compromise, which is observed when the femoral and its lateral femoral cutaneous branches are blocked. Once the geniculate nerve of interest is identified, the operator can use ultrasound guidance to surround nerve fascicles with an injectate mixture of anesthetic and corticosteroid, yielding decreased pain sensation at the joint capsule. Given the role of the geniculate nerve in providing sensory innervation to the joint capsule and knee ligaments, blockade of this nerve can serve as a useful tool for managing patients with acute knee pain secondary to OA.

Primary Pleural Schwannoma as Incidental Findings: An Unusual Case Report

Schwannomas are neurogenic, benign, slow growing tumours that originate in Schwann's intersecting fascicles of the peripheral nerves. This article reports the case of a previously healthy 51-year-old male, where a 9.0x6.5 cm (3.5x2.5 in) sized pleural mass was found after the patient presented a haemoglobin level of 3.2 g/dL in a blood smear at a routine check-up. The patient had no relevant medical, family, or psychosocial history and presented no relevant symptoms. After diagnosing and treating a chronic haemorrhoidal disease, the tumour was removed and studied. Demonstrating histopathological and immunohistochemical features of schwannoma, its uniqueness and rarity after successful management of the disease contributes to the medical literature as a histopathologic diagnostic standard and a therapeutic option for future cases of pleural schwannoma. Sharing the histopathologic features of schwannoma is not common, usually, the available case reports are lacking. The patient was able to recover fully and had no significant or severe complications associated with medical care.

Peripheral Nerve Innervation in Bilateral Cleft Hand Syndrome Elucidated by Ultrasound.

Bilateral cleft hand syndrome is a rare congenital malformation with complex anatomy. Previous reports have mainly focused on the description of bone and soft tissue abnormalities, but information about innervation is scarce. Knowledge of the peripheral nerve anatomy is helpful for surgical treatment, optimizing the reconstruction, and preventing iatrogenic damage. Following clinical assessment and conventional radiologic imaging, we used high-resolution ultrasound of both hands and forearms to image the peripheral nerves in a patient with severe bilateral cleft hand syndrome. The patient presented with two ulnar digits, a deformed thumb on the right, and a rudimentary thumb appendage on the left. In keeping with the tissue elements present and absent, we found a severe bilateral nerve size reduction of the median nerves, sparing the anterior interosseous nerve fascicles. The radial nerve and end branches were intact, and a slightly smaller ulnar nerve was found that ended in two digital branches to a single digit. Our study shows that in cleft hand syndrome the peripheral nervous system anatomy exactly reflects the presence and absence of the corresponding muscle and skin innervation areas. This information is helpful for planning a surgical-reconstructive approach and suggests a potential role for nerve ultrasound in the assessment of complex limb malformations.