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The lateral antebrachial cutaneous nerve (LACN) is the sensory branch of the musculocutaneous nerve and usually innervates the lateral aspect of the forearm. Isolated lesions are rare, of varied etiology and generally underdiagnosed. We present a retrospective descriptive study of electromyography performed at the General University Hospital of Castellón in the last 20 years with isolated NCAL lesion. We identified 11 cases (8 men and 3 women), average age 44 years (15-73 years). 73% were referred from traumatology. Only one patient was correctly guided in the application. 63.6% of cases noted hypoesthesia extending to the wrist and 18.2% to the thumb. The electromyographic study showed severe axonal involvement in 3 patients and moderate in 8. The symptoms were observed associated with surgery in 4 patients, manipulation of the elbow flexure in 4 cases and bicipital tendonitis in the rest. Four patients had a poor clinical outcome (3 with severe axonal involvement and 1 with moderate involvement). Isolated involvement of the NCAL is a rare and underdiagnosed alteration. It is important to suspect it in patients with hypoesthesia in the forearm, including the radial edge of the wrist or thumb, especially if it is associated with manipulations around the elbow flexure or bicipital tendonitis. Electromyography is useful in confirming the diagnosis, ruling out other differential diagnoses, and predicting prognosis. Knowing the location of this nerve during manipulations on the arm and placing patients in an appropriate posture during surgeries can help minimize cases.

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BACKGROUND: Cutaneous neuropraxia is the most common complication following distal biceps tendon repair (DBTR). Currently, no patient demographic factors have been implicated in its occurrence, course, or resolution. The purpose of this study is to explore various patient demographics and their association with postoperative neuropraxia. Further it investigates how mental health scores correlate with patient-reported outcomes, and whether occurrence of neuropraxia alters this association. METHODS: This retrospective review evaluates a consecutive series of patients who underwent distal biceps repair with a single-incision cortical button technique. Patients with reported outcome data at a minimum of 1 year (n = 47) were included for analysis. Demographic data including age, sex, body mass index (BMI), diabetes, smoking status, and occurrence of neuropraxia were recorded. Patient-reported outcome measures (PROMs) include the American Shoulder and Elbow Surgeons-Elbow (ASES-E) score, Single Assessment Numeric Evaluation (SANE) score, Visual Analog Scale (VAS) for pain, Disabilities of the Arm, Shoulder, and Hand Score (QuickDASH), and Veterans RAND 12 (VR-12) Mental Component Score (MCS) and Physical Component Score (PCS) quality-of-life assessment. RESULTS: Postoperative neuropraxia of any duration occurred in 45% (21/47) of patients in this cohort following DBTR. Of these, 62% (13/21) reported resolution of symptoms by the latest follow-up. Mean time to resolution of neuropraxia was 148 days. Patient age, BMI, smoking history, time to surgery, tear thickness, and increasing surgeon experience across the study period were not significantly associated with the incidence or time to resolution of postoperative neuropraxia. Scores for patient satisfaction, VAS, ASES, QuickDASH, SANE, VR-12 MCS, VR-12 PCS, and flexion ROM did not differ significantly between patients with and without postoperative neuropraxia. CONCLUSION: Patient satisfaction following DBTR was not significantly associated with postoperative neuropraxia. Patient and surgical characteristics did not influence the occurrence or time to resolution of neuropraxia. The occurrence of postoperative neuropraxia did not result in significant functional limitations.

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BACKGROUND: Many surgical strategies aim to treat the symptomatic neuroma of the superficial branch of the radial nerve (SBRN). It is still difficult to treat despite many attempts to reveal a reason for surgical treatment failure. The lateral antebrachial cutaneous nerve (LACN) is known to overlap and communicate with SBRN. Our study aims to determine the frequency of spreading of LACN fibers into SBRN branches through a microscopic dissection to predict where and how often LACN fibers may be involved in SBRN neuroma. METHODS: Eighty-seven cadaveric forearms were thoroughly dissected. The path of LACN fibers through the SBRN branching was ascertained using microscopic dissection. Distances between the interstyloid line and entry of LACN fibers into the SBRN and emerging and bifurcation points of the SBRN were measured. RESULTS: The LACN fibers joined the SBRN at a mean distance of 1.7 ± 2.5 cm proximal to the interstyloid line. The SBRN contained fibers from the LACN in 62% of cases. Most commonly, there were LACN fibers within the SBRN's third branch (59%), but they were also observed within the first branch, the second branch, and their common trunk (21%, 9.2%, and 22%, respectively). The lowest rate of the LACN fibers was found within the SBRN trunk (6.9%). CONCLUSION: The SBRN contains LACN fibers in almost 2/3 of the cases, therefore, the denervation of both nerves might be required to treat the neuroma. However, the method must be considered based on the particular clinical situation.

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Awareness of unique path of the superficial branch of the radial nerve and its unusual sensory distribution can help avoid potential diagnostic confusion. We present a unique case encountered during a routine dissection of a Central European male cadaver. An unusual course of the superficial branch of the radial nerve was found in the right forearm, where the superficial branch of the radial nerve originated from the radial nerve distally, within the supinator canal, emerged between the extensor digitorum and abductor pollicis longus muscles and supplied the second and a radial half of the third digit, featuring communications with the lateral antebrachial cutaneous nerve and the dorsal branch of the ulnar nerve. Due to dorsal emerging of the superficial branch of the radial nerve the dorsal aspect of the thumb was innervated by the lateral antebrachial cutaneous nerve. To our best knowledge such variation of the superficial branch of the radial nerve has never been reported before. This variation dramatically changes aetiology and manifestation of possible entrapment syndromes which clinicians should be aware of.

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Purpose: To evaluate the course of the cutaneous nerve regarding the first extensor compartment to determine whether the dorsal or volar approach is safer for local injection into the first extensor compartment guided by ultrasound. Methods: We dissected the radial side of the wrists from 28 cadavers (52 wrists). Four-points along the imaginary line were set: the styloid process and 1 cm, 2 cm, and 3 cm proximal to the styloid process. The numbers of superficial radial nerve (SRN) and lateral antebrachial cutaneous nerve (LACN) branches were counted, and distances from the imaginary line at these points and nerve diameters were recorded. Digital images were superimposed to observe overall distribution of cutaneous nerve. Results: There were means of 3.3 SRN and 0.9 LACN branches observed in each wrist. The mean number of both SRN and LACN branches was 2.3 on the dorsal side and 1.9 on the volar side. The superimposed images indicated that both the dorsal and volar sides comprised abundant cutaneous nerves and that their paths varied markedly between patients. However, we observed that larger nerves with meaningful diameters were more abundant on the dorsal than the volar side. Conclusion: There were similar numbers of cutaneous nerves on both the dorsal and volar sides; however, we observed greater abundance of thicker cutaneous nerves on the dorsal side, and these were closer to the reference line than on the volar side. This anatomical study suggests that the risk imposed to cutaneous nerves would therefore be reduced when injection on the volar side.

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INTRODUCTION: The lateral antebrachial cutaneous nerve (LACN) is a somatosensory nerve coursing in the lateral portion of the forearm. The nerve is located in a close proximity to the cephalic vein (CV) all along its course with a danger of being injured during venipuncture. The LACN also overlaps and communicates with the superficial branch of the radial nerve (SBRN) in the distal forearm and hand, making the awareness of their relationship of great importance in the treatment of neuroma. The aim of the study was to observe the relationship of the LACN to surrounding structures as well as its branching pattern and distribution. MATERIALS AND METHODS: Ninety-three cadaveric forearms embalmed in formaldehyde were dissected. The relationship of the LACN to surrounding structures was noted and photographed, and distances between the structures were measured with a digital caliper. The cross-sectional relationships of the LACN and SBRN to the CV were described using heatmaps. RESULTS: The emerging point of the LACN was found distally, proximally or at the level of the interepicondylar line (IEL). The LACN branched in 76 cases (81.7 %) into an anterior and posterior branch at mean distance of 47.8 ± 34.2 mm distal to the IEL. The sensory distribution was described according to the relationship of the LACN branches to the medial border of the brachioradialis muscle. The LACN supplying the dorsum of the hand was observed in 39.8 % of cases. The LACN and the SBRN intersected in 86 % of upper limbs with communications noticed in 71 % of forearms. The LACN was stated as the most frequent donor of the communicating branch resulting in neuroma located distal to the communication and being fed from the LACN. The relationship of the LACN and the CV showed that the IEL is the most appropriate place for the venipuncture due to maximal calibers of the CV and deep position of the LACN. The LACN was adjacent to the cubital perforating vein and the radial artery in all cases. The medial border of the brachioradialis muscle was observed less than 1.8 mm from the LACN. CONCLUSION: The study provides morphological data on the LACN distribution, branching pattern and relationship to surrounding structures in a context of clinical use in different spheres of medicine. The branching pattern of the LACN appears to be more constant compared to data provided by previous authors. We emphasized the meaning of cross-sectional relationship of the LACN to the CV to avoid venipuncture outside the cubital fossa if possible. The posterior branch of the LACN was predicted as appropriate donor of the graft for a digital nerve. The LACN appeared to be in a close proximity within the whole length of the brachioradialis muscle what the orthopedic surgeons must be concerned of. The meaning of the donor-nerve of the communicating branch in neuroma treatment was also introduced.

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INTRODUCTION: The superficial branch of the radial nerve (SBRN) and the lateral antebrachial cutaneous nerve (LACN) are sensory nerves coursing within the forearm in a close relationship. This high degree of overlap and eventual communication between the nerves is of great surgical importance. The aim of our study is to identify the communication pattern and overlap of the nerves, to localize the position of this communication in relation to a bony landmark, and to specify the most common communication patterns. MATERIALS AND METHODS: One hundred and two adult formalin-fixed cadaveric forearms from 51 cadavers of Central European origin were meticulously dissected. The SBRN, as well as the LACN, were identified. The morphometric parameters concerning these nerves, as well as their branches and connections, were measured with a digital caliper. RESULTS: We have described the primary (PCB) and secondary communications (SCB) between the SBRN and the LACN and their overlap patterns. One hundred and nine PCBs were found in 75 (73.53%) forearms of 44 (86.27%) cadavers and fourteen SCBs in eleven hands (10.78%) of eight cadavers (15.69%). Anatomical and surgical classifications were created. Anatomically, the PCBs were classified in three different ways concerning: (1) the role of the branch of the SBRN within the connection; (2) the position of the communicating branch to the SBRN; and (3) the position of the LACN branch involved in the communication to the cephalic vein (CV). The mean length and width of the PCBs were 17.12 mm (ranged from 2.33 to 82.96 mm) and 0.73 mm (ranged from 0.14 to 2.01 mm), respectively. The PCB was located proximally to the styloid process of the radius at an average distance of 29.91 mm (ranged from 4.15 to 97.61 mm). Surgical classification is based on the localization of the PCBs to a triangular zone of the SBRN branching. The most frequent branch of the SBRN involved in the communication was the third (66.97%). Due to the frequency and position of the PCB with the third branch of the SBRN, the danger zone was predicted. According to the overlap between the SBRN and the LACN, we have divided 102 forearms into four types: (1) no overlap; (2) present overlap; (3) pseudo-overlap; and (4) both present and pseudo-overlap. Type 4 was the most common. CONCLUSION: The patterns of communicating branch arrangements appeared to be not just a rare phenomenon or variation, but rather a common situation highlighting clinical importance. Due to the close relationship and connection of these nerves, there is a high probability of simultaneous lesion.

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BACKGROUND: Innervation of the thumb and radial part of the dorsum of the hand is achieved primarily by the radial nerve, which is usually blocked for hand surgery. Inefficient blocks occur because the lateral antebrachial cutaneous nerve also extends into this area. The question then arises, whether skin innervation and peripheral blocking techniques should be directed at from the innervation by these nerves or more by the dermatome and its spinal segments. METHODS: In 68 human upper limbs embalmed with Thiel's method, the topography of the lateral antebrachial cutaneous nerve (LACN), the superficial branch of the radial nerve (sbRN) and communicating branch (CB) were investigated by meticulous dissection from the cubital fossa to the most distal macroscopically dissectible branch, and the areas reached by these nerves were compared to the described dermatome. RESULTS: In 52.9% of all specimens, the LACN was found proximal to the rascetta, in 35.3% it extended to the base of the thumb, and in 8 cases (11.8%) it extended distally to the base of the thumb. In 50%, the LACN was anterolateral to the brachioradialis muscle, and in 38.2%, strictly lateral. Only in 8 cases (11.8%) the LACN presented itself running more dorsally and laterally. A CB was observed in 28 specimens (41.2%). Both investigated nerves were found to innervate the dermatomes of C6 and C7. CONCLUSIONS: The LACN should be considered for individual targeted blocks for surgical procedures and pain therapy within the wrist and thumb region as all nerves that might contribute to innervation of a targeted dermatome should be blocked.

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Dorsoradial forearm and hand pain was historically considered difficult to treat surgically due to a particular susceptibility of the radial sensory nerve (RSN) to injury and/or compression. A nerve block, if it were done at all, was directed at the region of the anatomic snuff box to block the RSN in an effort to provide diagnostic information as to the pain etiology. Even for patients with pain relief following a diagnostic block, resecting the RSN often proved unsuccessful in fully relieving pain. The solution to successful treatment of this refractory pain problem was the realization that the RSN is not the sole source of sensory innervation to the dorsoradial wrist. In fact, in 75% of people the lateral antebrachial cutaneous nerve (LABCN) dermatome overlaps the RSN with other nerves, such as the dorsal ulnar cutaneous nerve and even the posterior antebrachial cutaneous nerves, occasionally providing sensory innervation to the same area. With this more refined understanding of the cutaneous neuroanatomy of the wrist, the diagnostic nerve block algorithm was expanded to include selective blockage of more than just the RSN. In contemporary practice, identification of the exact nerves responsible for pain signal generation informs surgical decision-making for palliative neurolysis or neurectomy. This approach offers a systematic and repeatable method to inform the diagnosis and treatment of dorsoradial forearm and wrist pain.

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The most common procedure for the treatment of painful median nerve neuroma is coverage with vascularized soft tissue following external neurolysis. However, the ideal treatment should include reconnecting the proximal and distal stumps of the damaged nerve to allow the growth of regenerating axons to their proper targets for a functional recovery. We developed a useful technique employing radial artery perforator adipofascial flap including the lateral antebrachial cutaneous nerve (LABCN) to repair the median nerve by vascularized nerve grafting and to achieve coverage of the nerve with vascularized soft tissue. In an anatomical study of 10 fresh-frozen cadaver upper extremities, LABCN was constantly bifurcated into two branches at the proximal forearm (mean: 8.2 cm distal to the elbow) and two branches that run in a parallel manner toward the wrist. The mean length of the LABCN branches between the bifurcating point and the wrist was 18.2 cm, which enabled inclusion of adequate length of the LABCN branches into the radial artery perforator adipofascial flap. The diameters of the LABCN branches (mean: 1.7 mm) were considered suitable to bridge the funiculus of the median nerve defect after microsurgical internal neurolysis. In all cadaver upper extremities, the 3-cm median nerve defect at the wrist level could be repaired using the LABCN branches and covered with the radial artery perforator adipofascial flap. On the basis of this anatomical study, the median nerve neuroma was successfully treated with radial artery perforator adipofascial flap including vascularized LABCN branches.

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The forearm is an interesting donor site for non-vascularized nerve grafts, especially hand surgeons. Very few studies have described the use of the lateral and medial antebrachial cutaneous nerves (LABCN and MABCN, respectively) as vascularized nerve grafts (VNGs). The aim of this anatomical study was to analyze the characteristics and vascularization of these nerves to describe new potential donor sites for VNGs. Twelve forearms were dissected from fresh cadavers injected with red latex. The number of terminal branches, lengths, and proximal and distal diameters of both the LABCN and MABCN were studied. An anatomical description of the cutaneous perforator arteries from the radial and ulnar arteries that vascularized the nerve was also recorded: number of perforators, length, type of perforator (septo- or musculocutaneous), and location within the forearm (proximal, middle, and distal third). In over 80% of the specimens, the cutaneous perforator arteries from the radial and ulnar artery vascularized the LABCN and the MABCN, respectively. These arteries, found mostly in the proximal third of the forearm, had diameters >0.5mm. Most of them came from the radial and ulnar arteries (for LABCN and MABCN vascularization, respectively). In over 75% of the specimens, the nutrient arteries of both nerves also vascularized the superficial veins and the skin. We found that these nerves are vascularized by perforators arteries, which also participate in vein and skin vascularization. Altogether, this anatomical study shows that reconstructive surgeons could use new VNGs based on the perforator artery of the forearm.

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Dynamic compression of the lateral antebrachial cutaneous nerve (LABCN) occurs with forearm pronation when the LABCN becomes compressed by the lateral margin of the biceps tendon. LABCN compression is a rare occurrence and is often overlooked as an etiology for forearm pain. While this entity has been described in several case reports in the orthopedic literature, it has not yet been described in radiology literature. We present a case of LABCN compression by the biceps tendon which was suggested by high-resolution magnetic resonance neurography in combination with the clinical findings and was subsequently confirmed and corrected surgically.

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@#Isolated musculocutaneous nerve (MCN) lesion is rare and usually associated with direct trauma. Along with the rarity of this condition, other muscles involved in elbow flexion, such as brachioradialis and pronator teres, can mask the weakness induced by the MCN injury and make it difficult to identify it. Here, we report a 17-year-old patient with isolated MCN palsy following a single episode of anterior shoulder contusion. A lack of suspicion for this rare condition delayed diagnosis until 7 months post injury, when atrophy of muscles in the left upper arm became prominent and weakness of the elbow flexors persisted. After 6 months of rehabilitation therapy rather than undergoing surgical exploration, elbow flexor strength was nearly fully recovered but sensory symptoms remained. The mechanism of injury is speculated to be a sudden overloading of the anterior shoulder with extension and external rotation, which overstretched and compressed the MCN within the coracobrachialis muscle where the nerve is relatively fixed. Although isolated peripheral nerve injury is rare, it can be caused by a single episode of vigorous impact. Therefore, even in patients without any external wounds, careful physical examination with suspicion of peripheral nerve injury as one of the differential diagnoses is needed.

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BACKGROUND: The Conventus Distal Radius System (DRS) is an intramedullary fixation scaffold inserted into the lateral aspect of the distal radius. The purpose of this study was to identify insertion site anatomy to illustrate risks associated with the minimally invasive nature of radial-sided implant application. METHODS: Ten cadavers were utilized. Using fluoroscopy, the 1.1-mm Kirschner wire and template was introduced per manufacturer's guidelines, access guide assembled, and dissection carried out to the superficial radial nerve (SRN) with preservation of the native location. The access guide marked the insertion location for the side-cut drill. This point was measured in relationship to structures nearby, including the SRN, brachioradialis (BR), lateral antebrachial cutaneous nerve (LABCN), and radial styloid (RS). RESULTS: The large guide contacted the SRN in 4 of 10 cadavers and was volar to it in 6 of 10. When volar, the mean distance was 1.7 mm. The tip of the RS to the large access guide averaged 44.5 mm. The small guide contacted the SRN in 2 of 10, was volar to it in 4 of 10, and between the bifurcation in 4 of 10. When volar, the distance averaged 3.25 mm. When bifurcated, the distance from the small guide to both the dorsal and volar branches was 3.5 mm. The distance from the RS to the small guide averaged 37.8 mm. The LABCN was found in the field of dissection in 4 of 10 cadavers. CONCLUSIONS: Several structures are at risk during insertion of the Conventus DRS; thus, knowledge of the relevant anatomy of this minimally invasive approach is crucial to optimize outcomes and patient satisfaction, and to avoid nerve injury.

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OBJECTIVE: To define the anatomy of the lateral antebrachial cutaneous nerve (LABCN) and the cephalic vein (CV) in the anterior forearm region of living humans using ultrasonography for preventing LABCN injury during cephalic venipuncture. METHODS: Thirty forearms of 15 healthy volunteers were evaluated using ultrasonography to identify the point where the LABCN begins to contact with the CV, and the point where the LABCN separates from the CV. The LABCN pathway in the forearm in relation to a nerve conduction study was also evaluated. RESULTS: The LABCNs came in contact with the CV at a mean of 0.6±1.6 cm distal to the elbow crease, and separated from the CV at a mean of 7.0±3.4 cm distal to the elbow crease. The mean distance between the conventionally used recording points (point R) for the LABCN conduction study and the actual sonographic measured LABCN was 2.4±2.4 mm. LABCN usually presented laterally at the point R (83.3%). CONCLUSION: The LABCN had close proximity to the CV in the proximal first quarter of the forearm. Cephalic venipuncture in this area should be avoided, and performed with caution if needed.

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OBJECTIVE: To define the anatomy of the lateral antebrachial cutaneous nerve (LABCN) and the cephalic vein (CV) in the anterior forearm region of living humans using ultrasonography for preventing LABCN injury during cephalic venipuncture. METHODS: Thirty forearms of 15 healthy volunteers were evaluated using ultrasonography to identify the point where the LABCN begins to contact with the CV, and the point where the LABCN separates from the CV. The LABCN pathway in the forearm in relation to a nerve conduction study was also evaluated. RESULTS: The LABCNs came in contact with the CV at a mean of 0.6±1.6 cm distal to the elbow crease, and separated from the CV at a mean of 7.0±3.4 cm distal to the elbow crease. The mean distance between the conventionally used recording points (point R) for the LABCN conduction study and the actual sonographic measured LABCN was 2.4±2.4 mm. LABCN usually presented laterally at the point R (83.3%). CONCLUSION: The LABCN had close proximity to the CV in the proximal first quarter of the forearm. Cephalic venipuncture in this area should be avoided, and performed with caution if needed.

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BACKGROUND: The anatomy of the lateral antebrachial cutaneous nerve (LABCN) in relation to volar approaches to the distal radius is not well visited. With the increasing popularity of distal radius fracture fixation with volar locking plates, it is prudent to study the innervation pattern of the LABCN to minimize the risk of nerve injury. METHODS: Ten cadaveric distal radial forearms were dissected to study the relationship between the LABCN, flexor carpi radialis (FCR), superficial branch of radial nerve (SBRN), and scaphoid tubercle (ST). RESULTS: The LABCN coursed closer to the FCR than the SBRN, with branches traversing the tendon in two specimens. The LABCN was also noted to be intimately related to the radial artery, with an average distance of the LABCN from the lateral border of FCR was 6.4mm distally and 9.6mm proximally. CONCLUSIONS: There is a sparsely innervated corridor between the radial border of the FCR and terminal branches of the LABCN that provides safe access for volar approach to the distal radius.

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The superficial branch of the radial nerve (SBRN) is known for developing neuropathic pain syndromes after trauma. These pain syndromes can be hard to treat due to the involvement of other nerves in the forearm. When a nerve is cut, the Schwann cells, and also other cells in the distal segment of the transected nerve, produce the nerve growth factor (NGF) in the entire distal segment. If two nerves overlap anatomically, similar to the lateral antebrachial cutaneous nerve (LACN) and SBRN, the increase in secretion of NGF, which is mediated by the injured nerve, results in binding to the high-affinity NGF receptor, tyrosine kinase A (TrkA). This in turn leads to possible sprouting and morphological changes of uninjured fibers, which ultimately causes neuropathic pain. The aim of this study was to map the level of overlap between the SBRN and LACN. Twenty arms (five left and 15 right) were thoroughly dissected. Using a new analysis tool called CASAM (Computer Assisted Surgical Anatomy Mapping), the course of the SBRN and LACN could be compared visually. The distance between both nerves was measured at 5-mm increments, and the number of times they intersected was documented. In 81% of measurements, the distance between the nerves was >10 mm, and in 49% the distance was even <5 mm. In 95% of the dissected arms, the SBRN and LACN intersected. On average, they intersected 2.25 times. The close (anatomical) relationship between the LACN and the SBRN can be seen as a factor in the explanation of persistent neuropathic pain in patients with traumatic or iatrogenic lesion of the SBRN or the LACN.

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