Lateral Cutaneous Nerve Research Articles

Absence of musculocutaneous nerve bilaterally with variant motor innervations of flexors of arm

ABSTRACT Variations of the brachial plexus are of great interest for anatomists, clinicians and surgeons, in that they may be incorporated in day to day practice. A middle aged female cadaver on routine dissection showed absence of the musculocutanaous nerve bilaterally. The anterior compartment of both arms were supplied by the median nerve. The median nerve after supplying the coracobrachialis and biceps, gave a common branch for the brachialis and lateral cutaneous nerve of the forearm. The present case may be noted for its clinical and surgical significance in the variations of brachial plexus which can be useful for diagnostic and therapeutic purposes. Copyright © 2014, Indian Journal of Medical Specialities. Published by Reed Elsevier India Pvt. Ltd. All rights reserved.

P72: Selective paralysis of long thoracic nerve with concomitant involvement of the lateral cutaneous nerve of the forearm. An unusual form of Parsonage-Turner syndrome

P72: Selective paralysis of long thoracic nerve with concomitant involvement of the lateral cutaneous nerve of the forearm. An unusual form of Parsonage-Turner syndrome

Anatomic Findings and Complications After Surgical Treatment of Chronic, Partial Distal Biceps Tendon Tears: A Case Cohort Comparison Study

To describe pertinent anatomic findings during repair of chronic, partial distal biceps tendon tears and to compare the complications of surgery with a similar cohort of acute, complete tears. Group 1 included 14 patients (15 elbows) with partial tears managed operatively an average of 10 months from onset of injury or symptoms. Group 2 included a matched cohort of 16 patients (17 elbows) treated for complete, acute tears an average of 19 days from injury. A retrospective review of all 30 patients focused on demographic data, intraoperative findings, and postoperative complications. A single, anterior incision was used in all cases with multiple suture anchors or a bicortical toggling button for fixation of the repair. We evaluated 27 men and 3 women with an average age of 55 years (group 1) and 48 years (group 2). Intratendinous ganglion formation at the site of rupture of the degenerative tendon was observed in 5 cases of partial tears and none of the complete tears. Partial tears involved the lateral aspect or short head of the biceps tendon insertion in all cases. Postoperative complications included lateral antebrachial cutaneous nerve neuritis in 8 group 1patients and 6 group 2 patients and transient posterior interosseus nerve palsy in 3 group 1patients. Partial distal biceps tendon ruptures showed a consistent pattern of pathology involving disruption of the lateral side of the tendon insertion involving the small head of the biceps. Degenerative intratendinous ganglion formation was present in one third of cases. Repair of chronic, partial distal biceps tendon injuries may have a higher incidence of posterior interosseous and lateral antebrachial cutaneous nerve palsies. Therapeutic III.

A new pitfall in a sensory conduction study of the lateral antebrachial cutaneous nerve: Spread to the radial nerve

We describe a previously unreported pitfall, spread of the stimulus at the elbow to the radial nerve, in an antidromic sensory nerve conduction study of the lateral antebrachial cutaneous (LAC) nerve. Subjects consisted of 80 healthy volunteers, and both sides were examined for each subject. Besides routine recording of the LAC nerve, sensory nerve action potentials (SNAPs) of the radial nerve were recorded distally. The spread phenomenon occurred in 73 of 160 arms (46%), and the SNAP amplitude increased due to contamination of the radial SNAP up to 6.7 times the genuine LAC SNAP. In 10 arms (6%), the spread started before the LAC SNAP was saturated, and the genuine LAC SNAP was unknown due to an anatomical variation in at least 1 arm. Without monitoring distal radial SNAPs, the spread phenomenon will remain unrecognized. This pitfall undermines the reliability of the test.

Shoulder function after surgical treatment of displaced fractures of the humeral shaft: a randomized trial comparing antegrade intramedullary nailing with minimally invasive plate osteosynthesis

Minimally invasive plate osteosynthesis for humeral shaft fractures has been described recently, but there are no randomized studies comparing the clinical results for shoulder function between this technique and locking intramedullary nailing. A prospective randomized study was performed. Forty-one humeral shaft fractures (40 patients) were randomized to be treated with a minimally invasive plate (n=21) or a locking intramedullary nail (n=19). Clinical and radiographic outcome assessments were conducted at 1year postoperatively. Shoulder function was the primary outcome, as measured by the University of California, Los Angeles Shoulder Scale. Elbow function was measured by the Broberg-Morrey score, and fracture consolidation and complications were the main secondary outcomes. At 1year postoperatively, no significant difference was found with regard to shoulder function according to the University of California, Los Angeles scale between the minimally invasive plate and locking intramedullary nail (31.4 points vs 31.2 points, P=.98). There was also no difference in elbow function (94.8 points vs 94.1 points, P=.96). Complications were similar between the groups, without significant differences regarding infection (P>.99), symptomatic shoulder stiffness (P=.488), and neurapraxia of the lateral cutaneous nerve of the forearm (P=.475). Fracture union was achieved in all but 1 patient (2.4%) in the intramedullary nail group within 1year after the surgical procedure. There is no significant difference in shoulder function between antegrade intramedullary nailing and minimally invasive plate osteosynthesis for the treatment of displaced humeral shaft fractures, despite the limited power of our study.

High‐resolution ultrasound visualization of the subcutaneous nerves of the forearm: A feasibility study in anatomic specimens

The aim of this ultrasound-anatomical study was to evaluate the ability of high-resolution ultrasound (HRUS) to visualize and infiltrate small subcutaneous nerves of the forearm in anatomic specimens. Seven nonembalmed human bodies (4 men, 3 women; mean age at death, 60 years) were included in the study. Two investigators scanned the anatomic specimens using 15-MHz and 18-MHz HRUS transducers. The lateral, medial, and posterior antebrachial cutaneous nerves were scanned and interventionally marked with ink using HRUS-guidance. Subsequently, dissections were performed to assess the anatomical correlation of HRUS findings. All 3 nerves were identified consistently using HRUS. The precision of the ink-markings was excellent, with good correlation with the small peripheral branches of all 3 nerves. HRUS can identify precisely the small subcutaneous nerves of the forearm and may aid in both diagnosis and therapy in cases of neuropathy.

Unilateral absence of the musculocutaneous nerve with subsequent median nerve innervation: a case report with embryological and clinical significance (915.6)

Anatomical variations of the brachial plexus can have important surgical consequences. During a routine dissection procedure for teaching first year medical students, we observed a brachial plexus variation. The variation was found on the right extremity of a Caucasian female cadaver involving the complete absence of the musculocutaneous nerve and the lateral cutaneous nerve of forearm. In place of the musculocutaneous nerve, the median nerve was found to pierce the coracobrachialis and provide subsequent innervation to the biceps brachii and brachialis muscles. We believe this particular variation is relevant in clinical conditions such as correction of paralysis of the flexors of arm and forearm, neurotization, and post mastectomy reconstruction. Previous literature indicates that this embryologically relevant type of variation is much more common in the right upper extremity (fetal dissections).

Unilateral variant motor innervations of flexor compartment of arm (915.10)

Variations in the nerves of the upper limb are very important in routine surgeries, where these nerves are more prone for injuries; these variations may also help in interpretation of a nervous compression having unexplained clinical symptoms. The musculocutaneous nerve usually branches out from the lateral cord of brachial plexus. It innervates the coracobrachialis, biceps brachii and brachialis muscles and continues as the lateral cutaneous nerve of forearm without exhibiting any communication with the median nerve or any other nerve. We report a unilateral variation in motor innervations of the right arm in a 72‐year‐old Female cadaver. The musculocutaneous nerve was found to be piercing coracobrachialis muscle, supplying it and later continue as lateral cutaneous nerve of forearm. A muscular branch of the median nerve was supplying the short and long head of biceps muscle. In the middle of arm, the median nerve was found to be giving a separate branch, which supplied the brachialis muscle and continued in the cubital fossa with normal relation to biceps tendon and brachial artery. There was no variation seen in distribution of median nerve in the flexor compartment of forearm and hand. Knowledge of such anatomical variation is of interest to the anatomist and surgeons.

Lateral antebrachial cutaneous nerve compression after traumatic rupture of the long head of the biceps: a case series

Lateral antebrachial cutaneous (LABC) nerve compression is a rare but debilitating injury. There are limited data on the association of LABC nerve compression and proximal biceps rupture. We theorized that because of distal migration, the biceps muscle and tendon cause compression on the nerve. We present 2 cases in which patients had proximal biceps ruptures with tendon retraction and developed neurologic symptoms associated with the LABC nerve. To demonstrate our theory, we performed a cadaveric experiment. After making an incision to expose the entire biceps muscle and the musculocutaneous nerve and its branch into the LABC nerve, we marked each structure in 2-cm increments with a marking pen. The long head of the biceps was then cut to simulate a proximal biceps rupture. The relationship between the 3 structures was then studied, showing no change in position of the musculocutaneous nerve or LABC nerve. The biceps muscle and tendon had migrated distally toward the LABC nerve, demonstrating compression of the nerve. Proximal biceps tears commonly occur from trauma as well as iatrogenically after a biceps tenotomy for treatment of biceps tendinopathy. However, it is unusual for neuropathy of the LABC nerve to occur. Patients who develop neuropathy associated with the LABC nerve after a proximal biceps rupture can be effectively treated with LABC nerve decompression and biceps plasty. We found that this was an effective surgical treatment of LABC neuropathy without the need for proximal biceps tenodesis.

The Effective Injection Zone at the Popliteal Crease for Tibial and Common Peroneal Nerve Blocks and its Relation with the Origin Point of the Medial and Lateral Sural Cutaneous Nerves

El bloqueo nervioso popliteo puede ser utilizado para proporcionar anestesia y analgesia prolongada del miembro inferior y para aliviar el dolor postoperatorio severo y duradero. El objetivo fue determinar la localizacion anatomica de los nervios tibial (NT) y fibular comun (NFC) en el pliegue popliteo para un bloqueo nervioso efectivo. Se utilizaron 50 miembros inferiores frescos pertenecientes a 27 cadaveres adultos chinos (16 hombres y 11 mujeres, rango de edad entre 35-87 anos). Se utilizaron 22 cadaveres para identificar la localizacion de los nervios y los 5 restantes para determinar la profundidad de los nervios en una seccion transversal. El NT se encontro en el 50% de los casos desde el punto mas lateral del pliegue popliteo a 1,4 cm de la superficie. En el 20% de 50 muestras, el nervio cutaneo sural medial se ramifico por debajo o en el pliegue popliteo, mientras que el NFC se encontro en el 26% de los casos desde el punto mas lateral del pliegue popliteo a 0,7 cm de la superficie. Ademas, en el 6% de las muestras, el nervio cutaneo sural lateral se ramifico por debajo o en el pliegue popliteo. Nuestros resultados sugieren que el NT y NFC emergen del nervio ciatico a distancias variables del pliegue popliteo. Creemos que los resultados sobre la ubicacion de NT y NFC en el pliegue popliteo ofrecen una buena guia para el adecuado bloqueo nervioso.

Is there a profit to use the lateral antebrachial cutaneous nerve as a graft source in digital nerve reconstruction?

The digital nerves are commonly injured in emergency hand surgery practice. Lateral antebrachial nerve is of the autologous graft options available in forearm for digital nerve reconstruction. In this report, we aimed the evaluation of this nerve as an autologous nerve source for digital nerve repair. The overall sensorial results of the lateral antebrachial cutaneous nerve grafting and associated donor site morbidity in neglected digital nerve injuries of 15 patients in Zones 1 and 2 were evaluated Average length of the harvested lateral antebrachial cutaneous nerve grafts was 1.81 cm (0.75-3 cm.). Patients have been followed up for 20.7 months in average (range: 9.3-41 months). According to Highet and Sander criteria modified by Mackinnon and Dellon, nine patients were graded as S4, whereas six patients had S3+ values. According to modified ASSH guidelines for stratification of static 2PD results, excellent results were obtained in five patients, good results were achieved in eight patients and moderate results were obtained in two patients. Both the donor and recipient sites were evaluated with Semmes-Weinstein monofilament tests where satisfactory results have been obtained. Only two patients reported minimal cold intolerance at the donor site apart from the mild hypoesthesia noted at the anterolateral aspect of the middle forearm. Quite favorable clinical results with minimal donor site sensorial deficiency, anatomical and histomorphological similarity and being available in close location to surgical area brings up a matter to utilization of LABCN for digital nerve reconstruction.

Ultrasonographic Evaluation of Sural Nerve for Nerve Conduction Study

ObjectiveTo understand various morphologic types and locations of the sural nerve (SN) that are important for nerve conduction studies or nerve grafting procedures. The aim of this study was to describe the course and variations of the SN based on ultrasonographic findings for an adequate nerve conduction study.MethodsA total of 112 SNs in 56 volunteers with no history of trauma or surgery were examined by ultrasonography. The location and formation of the SNs in relation to the medial and lateral sural cutaneous nerve were investigated. We measured the horizontal distance between the SNs and the midline of the calf at the level of 14 cm from the lateral malleolus, and the distance between the SNs and the most prominent part of the lateral malleolus.ResultsSN variants was classified into four types according to the medial and lateral sural cutaneous nerve; type 1 (73.2%), type 2 (17.9%), type 3 (8.0%), and type 4 (0.9%). The mean distance between the SN and the midline of the calf was 1.02±0.63 cm, the SN and the most prominent part of the lateral malleolus was 2.14±0.15 cm.ConclusionVariations in the location and formation of the SN was examined by ultrasonography, and the results of this study would increase the accuracy of the SN conduction study.

Nerve injuries associated with gynaecological surgery

Key content Nerve injuries are a common complication of gynaecological surgery, occurring in 1.1–1.9% of cases. Patient mal‐positioning, incorrect placement of self‐retaining retractors, haematoma formation and direct nerve entrapment or transection are the primary causative factors in perioperative nerve injury. Nerves most commonly injured during surgery include the femoral, ilioinguinal, pudendal, obturator, lateral cutaneous, iliohypogastric and genitofemoral nerves. The majority of neuropathies resolve with conservative management and physiotherapy. Selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants and gamma‐aminobutyric acid (GABA) antagonists are of significant benefit in managing painful neuropathies. Learning objectives To gain an overview of the spectrum of different neuropathies that may occur following pelvic surgery. To learn about safe surgical techniques in the prevention of postoperative neuropathies. To review the clinical anatomy of the lumbo‐sacral and brachial plexuses. Ethical issues Neuropathies can cause considerable postoperative morbidity. Should neuropathies following gynaecology surgery be discussed routinely during consent taking? Neuropathies following surgery may have considerable medico‐legal implications.

Medial and lateral antebrachial nerve conductions: Orthodromic or antidromic?

Introduction: Antidromic stimulation is usually used in the evaluation of lateral antebrachial cutaneous nerve (LABCN) and medial antebrachial cutaneous nerve (MABCN). This study was conducted to evaluate the relationship between orthodromic and antidromic stimulations of these nerves. Materials and Methods: Medial and lateral antebrachial conduction studies by antidromic and orthodromic stimulation. Results: Sensory nerve action potential (SNAP) amplitudes were larger with antidromic stimulation in the majority of subjects. The lateral antebrachial SNAP amplitude was 20.5 ± 9.29 μV with antidromic stimulation and 14.6 ± 6.13 μV with orthodromic stimulation (P < 0.001). Medial antebrachial SNAP amplitudes were 12.8 ± 4.93 μV using antidromic stimulation and 6.5 ± 3.84 μV with orthodromic stimulation (P < 0.001). Sensory conduction velocities were faster with orthodromic lateral antebrachial stimulation (P = 0.002) whereas velocities were similar in medial antebrachial nerve. Supramaximal stimulation of MABCN was not possible in half of the nerves sampled to avoid the muscle artifact. Conclusion: Orthodromic stimulation of LABCN and MABCN are easy to perform and can be supplanted for antidromic stimulation in which Supramaximal stimulation may not be possible in some individuals.

An innovative external fixator for the management of trochanteric fractures of the femur

Purpose Recent published studies have compared the use of external fixation in elderly patients with trochanteric fractures with the more conventional methods of fixation such as a sliding hip screw. This is the first prospective study to report the outcomes of external fixation in a larger patient population that includes young and healthy adults. Materials and methods A total of patients with intertrochanteric fractures were treated using a newly developed uniplanar external fixator (AlexFix). All patients received local anaesthesia in the form of femoral and lateral cutaneous nerve blocks. There were 60 men and 140 women, mean age 71.09 (24-91) years. Patients were followed up for a period of 24 ± 2.1 months. Results The average operative time (and SD) was 26.22 ± 5.9 min. The average use of radiation intraoperatively was 16.67 ± 3.5 s. Hospital stay was short, with an average of 4.3 ± 1 days. No intraoperative complications were encountered. Blood loss was negligible and none of the patients received any blood transfusion. The mean time for union was 10.5 ± 1.1 weeks. The most common postoperative complications encountered were superficial pin-tract infection in 16 patients (8%) and deep pin-tract infection in seven patients (3.5%). Varus malunion occurred in five patients (2.5%). No implant failure or refracture was recorded. Conclusion External fixation of trochanteric fractures is an effective, safe and reliable treatment method. It offers minimal operative and anaesthetic risks, no blood loss, early mobilization and a short hospital stay, with low morbidity and mortality.

Absence of the musculocutaneous nerve in the right upper extremity: An unusual anatomical variation with potential clinical relevance

Neural variations of the brachium constitute a significant anatomical and clinical entity. Variations in median and musculocutaneous nerves are common, whereas the absence of the musculocutaneous nerve (McN) is very rare. The present report is on the absence of the McN observed in the right upper extremity of a middle-aged Nigerian male cadaver during routine educational dissection in the Department of Anatomy, Ebonyi State University, Nigeria. We observed three separate branches from the median nerve innervating the coracobrachialis muscle, biceps brachii, and brachialis muscles. The muscles that are usually innervated by the McN were innervated by the median nerve in this case. Also, the longest and more distal of these branches (branch to brachialis muscles) pass between the biceps and the brachialis muscle. In the cubital fossa, it lies at the lateral margin of the biceps tendon where it continues as the lateral cutaneous nerve of the forearm. The presence of this anomaly should be considered during surgical interventions and clinical investigations of the arm as this may help plan a surgical procedure in the region of axilla and the arm, traumatology of the shoulder joint, and plastic and reconstructive repair.

Study of sural nerve complex in human cadavers.

Aim. The sural nerve complex (SNC) consists of four named components: medial sural cutaneous nerve (MSCN), lateral sural cutaneous nerve (LSCN), peroneal communicating nerve (PCN), and sural nerve (SN). The formation and distribution of the sural nerve vary in different individuals. SN is universally recognized by surgeons as a site for harvesting an autologous nerve graft. The nerve is widely used for electrophysiological studies. Hence the study of sural nerve complex was taken up. Method. SNC was observed by dissecting 100 lower limbs in the department of anatomy at three different medical colleges, over a period of 10 years. Result. Typical SN was observed in 60% of the cases. MSCN was present in all the cases; in 15% of the cases the MSCN followed an intramural course. LSCN was present in 80% of the cases. PCN was present in 70% of the cases and in most of the cases calibre was larger than that of MSCN. Conclusion. The knowledge about the variation in the origin and course of the SN is important in evaluating sensory axonal loss in distal axonal neuropathies and should be borne in mind by clinicians and surgeons.

An Amazing Abnormality in the Course of the Musculocutaneous Nerve

The musculocutaneous nerve drive from the brachial plexus’s lateral cord and it is one of the terminal branches of this plexus. Commonly, it pierces the coracobrachialis muscle and then innervates the anterior department muscles of the arm. It also course at the lateral part of the the forearm while it terminates as the lateral antebrachial cutaneous nerve. The course and branching pattern variations of the musculocutaneous nerve are reported by several authors previously. We found a very rare variation during the dissection of a 60 years old male cadaver. In our case, the musculocutaneous nerve had a varied course which hasn’t been determined until now. It was terminating in the distal third of the arm as divided into two major branches. While the lateral branch continued as the lateral antebrachial cutaneous nerve, the medial branch, which was thicker than the lateral branch, descended downward in the medial side of the arm and passed into the cubital fossa. This medial branch was nearly close to the vessels. Eventually it was attaching to the median nerve at the forearm. The information about these variations are very important for clinicians and surgeons because of the relationships between the medial branch’s course and the important of anatomical structures in the forearm.

Superficial radial nerve–lateral antebrachial cutaneous nerve anatomic variation

IntroductionThis study focuses on an anatomic variation in which the lateral antebrachial cutaneous nerve (LACN) innervates the radial border of the dorsum of the hand and thumb in addition to, or replacing, the superficial radial nerve (RSN). Here, we propose a technique of nerve conduction that identifies this variation.MethodsWe studied nerve conduction in 200 upper limbs of two series of 50 volunteers. We sought evidence of the aforementioned variation on the dorsum of the hand and in the thumb.ResultsWe found eight occurrences of this variation on the dorsum of the hand and 11 variants on the thumb within the two respective series of 100 upper limbs studied.DiscussionThe RSN–LACN anatomic variation can be studied using nerve conduction. The knowledge of this variation is particularly important for the evaluation of proximal radial nerve injury.

Distal Biceps Brachii Tendon Rupture Resulting in Acute Compartment Syndrome

Distal biceps brachii tendon rupture is an uncommon injury. Compartment syndrome of the upper arm is rarely described in the literature. The diagnosis of upper arm compartment syndrome requires a high index of suspicion, and emergent surgical treatment with fasciotomy in the acute setting is necessary to avoid devastating neurovascular complications. This article reports a case of acute compartment syndrome of the anterior compartment of the upper arm after a complete rupture of the distal biceps brachii tendon. A healthy 45-year-old man presented with increasing arm pain; paresthesia in the lateral antebrachial cutaneous nerve distribution; and a tense, swollen anterior compartment of his upper arm. Side port catheter absolute pressure measurement was 83 mm Hg with a diastolic blood pressure of 92 mm Hg. The patient underwent an emergent fasciotomy and was found to have a complete rupture of his distal biceps brachii tendon. He subsequently underwent distal biceps tendon repair and delayed primary closure of his incision. Postoperatively, his paresthesia improved and he has no neurological deficit. There is a paucity of case reports describing compartment syndrome after rupture of either the proximal or distal end of the biceps brachii tendon, and none of the reports describe compartment syndrome of the upper arm after rupture of the distal biceps tendon. This article highlights an unusual complication of an uncommon injury and reviews diagnostic and treatment principles for the management of acute compartment syndrome of the upper arm.