Elbow Arthroscopy: Pearls to Avoid Nerve Injuries.

Elbow arthroscopy is a useful tool that can be applied in a variety of surgical indications. However, performing the procedure safely demands a thorough understanding of the proximity of neurovascular structures around the elbow. Although nerve injuries in elbow arthroscopy are rare, complications can further be avoided by adhering to a set of principles designed to protect the surrounding neurovascular structures. Before making portals, the surgeon should palpate and mark the ulnar nerve to confirm its location in the groove. Next, the joint should be insufflated with fluid to distend the joint capsule and increase the distance between instruments and the anterior neurovascular structures. Anterior portals ideally should be made proximal to the medial and lateral epicondyles, thereby increasing distance from the median and radial nerve, respectively. Once in the joint, it is critical to stay oriented by maintaining instruments and the articular surfaces in the same view. Special caution should be exercised when in proximity to the capsule in the posteromedial gutter to protect the ulnar nerve. Similarly, the anterior inferior capsule should be approached with caution, as its violation puts branches of the radial nerve, specifically the posterior interosseous nerve, at risk. Elbow arthroscopy can be safely performed with proper knowledge and application of anatomy around the elbow when making portals and understanding at-risk areas beyond the capsule when working within the joint.

A bilateral four-headed brachialis muscle with a variant innervation: a cadaveric report with possible clinical implications.

PURPOSE: Anterior compartment muscles of the arm present high morphological variability, with possible clinical significance. The current cadaveric report aims to describe a bilateral four-headed brachialis muscle (BM) with aberrant innervation. Emphasis on the embryological background and possible clinical significance are also provided. METHODS: Classical upper limb dissection was performed on an 84-year-old donated male cadaver. The cadaver was donated to the Anatomy Department of the National and Kapodistrian University of Athens. RESULTS: On the left upper limb, the four-headed BM was supplied by the musculocutaneous and the median nerves after their interconnection. On the right upper limb, the four-headed BM received its innervation from the median nerve due to the musculocutaneous nerve absence. A bilateral muscular tunnel for the radial nerve passage was identified, between the BM accessory heads and the brachioradialis muscle. CONCLUSION: BM has clinical significance, due to its proximity to important neurovascular structures and frequent surgeries at the humerus. Hence, knowledge of these variants should keep orthopedic surgeons alert when intervening in this area. Further dissection studies with a standardized protocol are needed to elucidate the prevalence of BM aberrations and concomitant variants.

Superficial branch of the radial nerve passing through the supinator canal, emerging between the extensor digitorum and abductor pollicis longus muscles and consequently supplying the second finger and radial portion of the third finger: a case report and clinical implications.

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.

Anatomical study of the safety corridor for bridge plating positioned on the lateral border of the humerus.

PURPOSE: This study shows the danger zone and the safety corridor in the lateral approach with bridge plating by measuring the distance between the lateral side of the plate positioned on the lateral aspect of the humerus and the radial nerve after it pierces the lateral intermuscular septum, in the different forearm positions. METHODS: Forty arms of 20 human cadavers were used, the radial nerve was identified and marked on the lateral surface the radial nerve at the exit of the lateral intermuscular septum and anteriorisation of the nerve in relation to the humeral shaft and the lateral epicondyle was also marked. The distances were measured with a digital caliper. A submuscular extraperiosteal corridor was created, proximally between the biceps brachialis and deltoid muscle and distally between the triceps and brachioradialis muscle, followed by the positioning of the low contact large fragments contoured plate with 14 combined holes (fixed and cortical angle), inserted from distal to proximal. Measurements were performed in four positions (elbow flexion with forearm pronation, elbow flexion with forearm supination, elbow extension with forearm pronation and elbow extension with forearm supination). RESULTS: Significant statistical differences occurred with the different positions, and the elbow flexion with forearm supination was shown to be the position that provides the safest submuscular extraperiosteal corridor in a lateral approach of the humerus. CONCLUSION: The danger zone of radial nerve is an area that extends from 15 cm to 5 cm proximal to the lateral epicondyle and the safest way to create a submuscular and extraperiosteal corridor in the lateral region of the humerus is with the elbow in flexion and the forearm in supination.

Safe zones in dorsal portals for wrist arthroscopy: a cadaveric study.

The standard dorsal portals are the most commonly used in wrist arthroscopy. This cadaveric study aims to determine safe zones, by quantitatively describing the neurovascular relationships of the dorsal wrist arthroscopy portals: 1-2, 3-4, midcarpal radial, midcarpal ulnar, 4-5, 6-radial and 6-ulnar. The neurovascular structures of twenty-one fresh frozen human cadaveric upper limbs were exposed, while the aforementioned portals were established with needles through portal sites. The minimum distance between portals and: dorsal carpal branch of radial artery, superficial branch of radial nerve, posterior interosseous nerve and dorsal branch of ulnar nerve, were measured accordingly with a digital caliper, followed by statistical analysis of the data. The median and interquartile range for each portal to structures at risk were determined and a safe zone around each portal was established. Free of any neurovascular structure safe zones surrounding 1-2, 3-4, midcarpal radial, midcarpal ulnar, 4-5, 6-radial and 6-ulnar portals were found at 0.46mm, 2.33mm, 10.73mm, 11.01mm, 10.38mm, 5.95mm and 0.64mm respectively. Results of statistical analysis from comparisons between 1-2, 3-4 and midcarpal radial portals, indicated that 1-2 was the least safe. The same analysis among 3-4, midcarpal radial, midcarpal ulnar and 4-5 portals indicated that midcarpal portals were safer, while 3-4 was the least safe. Results among midcarpal ulnar, 4-5, 6-radial and 6-ulnar portals indicated that 6-radial and specifically 6-ulnar were the least safe. This study provides a safe approach to the dorsal aspect of the wrist, enhancing established measurements and further examining safety of the posterior interosseous nerve.

Clinical anatomy of the lateral antebrachial cutaneous nerve: Is there any safe zone for interventional approach?

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.

Anatomical considerations for nerve transfer in axillary nerve injury.

This study investigated the anatomical details of the axillary and radial nerves in 50 upper limbs from 29 adult formalin-embalmed cadavers, and ten fresh upper limbs. The focus was on understanding the course, division, and ramifications of these nerves to improve treatment of shoulder dysfunction caused by axillary nerve damage. The axillary nerve divided anteriorly and posteriorly before passing the quadrangular space in all specimens, with specific distances to the first ramifications. It was found that the deltoid muscle's clavicular and acromial parts were always innervated by the anterior division of the axillary nerve, whereas the spinous part was variably innervated. The longest and thickest branches of the radial nerve to the triceps muscles were identified, with no statistically significant differences in fiber numbers among triceps branches. The study concludes that nerve transfer to the anterior division of the axillary nerve can restore the deltoid muscle in about 86% of shoulders, and the teres minor muscle can be restored by nerve transfer to the posterior division. The medial head branch and long head branch of radial nerve were identified as the best donor options.

Superficial branch of the radial nerve regularly contains fibers from the lateral antebrachial cutaneous nerve: A role in neuroma treatment.

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.

The posterior interosseous nerve at the proximal forearm: anatomical study and clinical correlation / El nervio interóseo posterior en el antebrazo proximal: estudio anatómico y correlación clínica

SUMMARY: The deep branch of the radial nerve (DBRN) runs through the radial tunnel, which is a muscle-aponeurotic structure that extends from the humeral lateral epicondyle to the distal margin of the supinator muscle (SM). The Posterior Interosseous Nerve (PIN) originates as a direct continuation of the DBRN as it emerges from the SM and supplies most of the muscles of the posterior compartment of the forearm. The PIN can be affected by compressive neuropathies, especially at the "Arcade of Frohse". Its preservation is of special interest in surgical approaches to proximal radius fractures and in compressive syndromes release, for which surgeons must have an adequate anatomical knowledge of its course. This descriptive cross-sectional study evaluated 40 upper limbs of fresh cadavers. The diameters of the DBRN, the length of the radial tunnel, and the distances to the supinator arch, PIN emergence and PIN bifurcation were measured. The deep branch of the radial nerve (DBRN) has a course of 23.8 ± 3.7 mm from its origin to the supinator arch, presenting a diameter of 2.2 ± 0.3 mm at that level. The length of the radial tunnel was 42.2 ± 4 mm. The PIN originated 70.7 ± 3.5 mm distal to the lateral epicondyle. Type I corresponds to the division of the PIN during its journey through the radial tunnel, presenting in 35 % of cases, and Type II corresponds to the division of the PIN distal to its emergence from the radial tunnel presenting in the remaining 65 %. This study enriches the knowledge of the PIN and provides useful reference information on a Latin American mestizo sample. We propose the division pattern of the PIN into two types. Future studies may use this classification not only as a qualitative variable, but also include quantitative morphometric measurements.

El ramo profundo del nervio radial (RPNR) discurre por el túnel radial, que es una estructura músculo- aponeurótica que se extiende desde el epicóndilo lateral del húmero humeral hasta el margen distal del músculo supinador (MS). El nervio interóseo Posterior (NIP) se origina como una continuación directa del RPNR cuando emerge del MS e inerva la mayoría de los músculos del compartimiento posterior del antebrazo. El NIP puede verse afectado por neuropatías compresivas, especialmente en la "Arcada de Frohse". Su conservación es de especial interés en los abordajes quirúrgicos de las fracturas proximales de radio y en la liberación de síndromes compresivos, para lo cual los cirujanos deben tener un adecuado conocimiento anatómico de su curso. Este estudio descriptivo transversal evaluó 40 miembros superiores de cadáveres frescos. Se midieron los diámetros de la RPNR, la longitud del túnel radial y las distancias al arco supinador, la emergencia del NIP y la bifurcación del NIP. El RPNR tenía un recorrido de 23,8 ± 3,7 mm desde su origen hasta el arco supinador, presentando un diámetro de 2,2 ± 0,3 mm a ese nivel. La longitud del túnel radial fue de 42,2 ± 4 mm. El NIP se originó 70,7 ± 3,5 mm distal al epicóndilo lateral. El tipo I corresponde a la división del NIP durante su recorrido por el túnel radial presentándose en el 35 % de los casos, y el tipo II corresponde a la división del NIP distal a su salida del túnel radial presentándose en el 65 % restante. Este estudio enriquece el conocimiento del NIP y proporciona información de referencia útil sobre una muestra de mestizos latinoamericanos. Proponemos el patrón de división del NIP en dos tipos. Futuros estudios pueden utilizar esta clasificación no solo como una variable cualitativa, sino también incluir medidas morfométricas cuantitativas.

A rare variation of radial nerve coexisting with the intercalated ectopic muscle from latissimus dorsi muscle / Una rara variación del nervio radial que coexiste con el músculo ectópico intercalado del músculo latísimo del dorso

SUMMARY: The axilla is the main communication channel connecting the upper limbs, the neck and chest. Stabilization of the internal structure is essential for upper limb and shoulder mobility. In this case, we observed and recorded the characteristics of the variation of the radial nerve as well as the intercalated ectopic muscle from latissimus dorsi muscle. The position relationship between both, was also particularly noted by us. In view of the presence of the variation we reported, related clinical research, surgery and disease diagnosis are expected to take this case into account.

La axila es el principal canal de comunicación que conecta los miembros superiores, el cuello y el tórax. La estabilización de la estructura interna es fundamental para la movilidad del miembro superior y del hombro. En este caso observamos y registramos las características de la variación del nervio radial así como del músculo ectópico intercalado del músculo latísimo del dorso. La relación de posición entre ambas también fue significativa en este estudio. En vista de la presencia de la variación que informamos, se espera que la investigación clínica relacionada con la cirugía y el diagnóstico de la enfermedad tengan en cuenta este caso.

Inervación del músculo braquiorradial en individuos brasileños: aspectos anatomo-clínicos de la biometría de origen y distribución nerviosa / Innervation of the brachioradialis muscle in Brazilian individuals: anatomo-clinical aspects of the biometry of origin and nervous distribution

El nervio para el músculo braquiorradial (BR) ha sido utilizado en transferencias nerviosas para recuperaciones en funciones de la mano como consecuencias de lesiones que afectan el plexo braquial. Con el propósito de investigar el número y localización biométrica de los ramos primarios provenientes del nervio radial y puntos motores respecto un punto de referencia ubicado en la región del codo, se estudiaron 30 miembros superiores de individuos adultos brasileños, de la Universidad Estadual de Ciencias da Saúde de Alagoas, Maceió, Brasil. Las muestras se encontraban fijadas en solución de formaldehído al 10 %, de los cuales 15 miembros eran derechos y 15 izquierdos. Como punto de referencia se utilizó una línea que pasó a través de las partes más prominentes de los epicóndilos humerales, línea bi-epicondilea (LBE). Con respecto al origen nervioso para el músculo BR, todos los ramos se originaron a partir del nervio radial (NR). El promedio de la cantidad de Ramos Primarios (RP) fue de 1,53 (DS 0,73). En 18 muestras (60 %) se observó sólo un RP; en 8 casos (26,7 %) se encontraron 2 RP, mientras que en 4 casos (13,3 %) de la muestra se observaron 3 RP. Sobre la localización biométrica de los orígenes de los RP, es importante mencionar que todos se ubicaron proximal a la LBE. En promedio, estos se ubicaron a 38 mm (DS 0,9); 29 mm (DS 1,2) y 22 mm (DS 1,0) para el primer, segundo y tercer RP, respectivamente. En relación a los puntos motores (PM), en 4 casos (13 %) se observó 1 PM dado por la penetración directa de un ramo primario, en 13 casos (43 %) existieron 2 PM, en 8 casos (27 %) se encontraron 3 PM y en 5 casos (17 %) se observaron 4 PM. En tres casos (10 %) la inervación hacia el músculo BR emitió filetes nerviosos hacia el músculo extensor radial largo del carpo. Los resultados expuestos en esta investigación son un importante aporte para bloqueos nerviosos, estimulaciones eléctricas y transferencias nerviosas.

The nerve for the brachioradialis muscle (BR) has been used in nerve transfers for recoveries in functions of the hand as a consequence of lesions affecting the brachial plexus. With the purpose of investigating the number and biometric location of the primary branches coming from the radial nerve and motor points with respect to a reference point located in the elbow region, thirty upper limbs of Brazilian adult individuals from the State University of Sciences of Saúde de Alagoas, Maceió, Brazil were used. The samples were fixed in 10 % formaldehyde solution, of which 15 were right and 15 left. As a reference point, a line was used that passed through the most prominent parts of the humeral epicondyls, bi-epicondilar line (BEL). With respect to the nervous origin for the BR muscle, all the branches originated from the radial nerve (RN). The average number of primary branches (PB) was 1.53 (SD 0.73). In 18 samples (60 %) only one PB was observed; in 8 cases (26.7 %) 2 PB were found, while in 4 cases (13.3 %) of the sample 3 PB were observed. Regarding the biometric location of the origins of PB, it is important to mention that all were located proximal to the BEL. On average, these were located at 38 mm (SD 0.9); 29 mm (DS 1.2) and 22 mm (DS 1.0) for the first, second and third PB, respectively. In relation to the motor points (MP), in 4 cases (13 %) 1 MP was observed as direct penetration of the PB, in 13 cases (43 %) there were 2 MP, in 8 cases (27 %) they found 3 MP and in 5 cases (17 %) 4 MP were observed. In three cases (10 %) the innervation towards the BR muscle emitted nerve fillets towards the extensor carpi radialis longus muscle. The results presented in this investigation are an important contribution to nerve blocks, electrical stimulations and nerve transfers.

Rama muscular hipertrófica de la arteria recurrente radial (Cuerda de Henry) en relación con el ramo profundo del nervio radial: reporte de caso / Hypertrophic muscular branch of radial recurrent artery (Leash of Henry), in relation to the deep branch of radial nerve: case report

La arteria recurrente radial nace en el extremo proximal de la arteria radial y desde ahí asciende oblicuamente para anastomosarse con la arteria colateral radial, entregando en ese trayecto una serie de ramas para los músculos cercanos. Dicha arteria junto con sus ramas fueron descritas (por su importancia en abordajes quirúrgicos) por Arnold K. Henry como "the radial leash". Actualmente en clínica se utiliza el nombre "leash of Henry" para referirse a una o más ramas musculares de la arteria recurrente radial, sobretodo cuando cuando se encuentran en relación con el ramo profundo del nervio radial, pudiendo llegar a causar compresiones de dicho nervio en algunos casos. Se realizó una descripción de caso de una leash of Henry atípica, encontrada en una muestra cadavérica del laboratorio de anatomía de la Universidad Católica del Maule, de sexo masculino y nacionalidad chilena. La arteria encontrada corresponde a la rama de mayor calibre de la arteria recurrente radial, que se dirige directamente al músculo extensor de los dedos, dibujando un trayecto horizontal y cruzando por anterior al ramo profundo del nervio radial. Esta hallazgo difere a lo descrito por Henry y otros autores más recientes, y por lo tanto aporta información potencialmente útil a la hora de realizar procedimientos quirúrgicos que requieran un abordaje posterior o lateral de la cabeza del radio, como también descompresiones del nervio radial en esta zona.

The radial recurrent artery originates at the proximal end of the radial artery and from there ascends obliquely to anastomosing with the radial collateral artery. It gives off several branches for nearby muscles on its path. This artery along with its branches were described (due to its importance in surgical approaches) by Arnold K. Henry as "the radial leash". Currently, in clinical terms, the name "Leash of Henry" is used to refer to one or more muscular branches of the radial recurrent artery, especially when they are in relation to the deep branch of the radial nerve, and may cause compression of the nerve in some cases. A case description of an atypical Leash of Henry was found, found in a Chilean, male cadaveric sample of the anatomy laboratory, Universidad Católica del Maule. The artery corresponds to the branch of greater caliber of the recurrent radial artery, which goes directly to the extensor digitorum muscle. It draws a horizontal path and crosses the deep branch of the radial nerve anteriorly. This finding differs from what was described by Henry and other more recent authors. Therefore, this is potentially useful information when performing surgical procedures that require a posterior or lateral approach to the radius head, as well as radial nerve decompressions in this area.

Inervación del músculo extensor radial largo del carpo en individuos brasileños: biometría de su origen y distribución / Innervation of the extensor carpi radialis longus muscle in Brazilian individuals: biometry of its origin and distribution

El músculo extensor radial largo del carpo (MERLC) es un músculo localizado en el compartimiento posterior (extensor-supinador) del antebrazo y tiene gran importancia en el cierre del puño. Hay pocos estudios biométricos con respecto al punto de origen de sus ramos de inervación, así como sobre la distribución de los mismos. Basado en lo anterior, se estudiaron 30 miembros superiores, formolizados, de individuos adultos Brasileños, de la Facultad de Medicina de la Universidad Estadual de Ciencias da Saúde de Alagoas, Maceió, Brasil. Luego de localizar el nervio, se midió la distancia entre el origen del ramo primario y el de los puntos motores respecto a la línea biepicondílea (LBE), los cuales fueron visualizados y disecados utilizando una lupa. El nervio en cuestión, se observó a nivel del brazo o proximal a LBE en 28 casos (93 %) y los 2 restantes a nivel de esta línea (7 %). Los ramos para el ERLC se originaron a partir del nervio radial, observando un ramo primario en 20 miembros (80 %), y en los restantes 10 (20 %) se observaron 2 ramos primarios, promediando 1,3 ramos (DS 0,5). El origen más proximal del primer ramo primario (RP) independiente de que si existían 1 o 2 fue en promedio 3 cm (DS 1,0) proximal a LBE. El PM más distal, se ubicó distal a LBE en 24 casos con un promedio de 1,9 cm (DS 1,0); localización a nivel de LBE en 3 casos. Sólo en 3 casos el PM más distal se encontró proximal a LBE, en un promedio de 0,8 cm (DS 0,5). La distribución de puntos motores fue variable, ya que muchas veces los RP se bifurcaban en ramos secundarios y éstos, a su vez se dividían hasta 6 veces en ramos terciarios que penetraban en el músculo. El conocimiento biométrico del origen del nervio del MERLC, así como su distribución, es un aporte importante al área anátomo-quirúrgica, así como, su utilización en bloqueos nerviosos, transferencias nerviosas y zonas de ubicación de electrodos con propósitos de estimulación eléctrica en pacientes que necesiten rehabilitar la acción de musculatura extensora radial lesionada.

The extensor carpi radialis longus muscle (ECRLm) is located in the posterior compartment (extensorsupinator) of the forearm and has great importance in the closure of the hand. There are few biometric studies with respect to the point of origin of their branches of innervation, as well as on the distribution of them. For this study, 30 upper limbs, formalized, of Brazilian adult individuals were used, from the Faculty of Medicine of the Universidad Estadual de Ciencias da Saúde de Alagoas, Maceió, Brazil. After locating the nerve, we measured the distance between the origin of the primary branch and that of the motor points with respect to biepicondilar line (BEl), which were visualized and dissected using a magnifying glass. The nerve in question was observed at the level of the arm or proximal to BEl in 28 cases (93 %) and the remaining 2 at the level of this line (7 %). The branches for the ECRLm originated from the radial nerve, observing a primary branch in 20 limbs (80 %), and in the remaining 10 (20 %) two primary branches were observed, averaging 1.3 branches (SD 0.5). The most proximal origin of the first primary branch (PB) independent of whether there was 1 or 2 was on average 3 cm (SD 1.0) proximal to BEl. The most distal MP was distal to BEl in 24 cases with an average of 1.9 cm (SD 1.0); location at the BEl level in 3 cases. Only in 3 cases was the most distal MP found proximal to BEl, an average of 0.8 cm (SD 0.5). The distribution of motor points was variable, since many times the PB bifurcated into secondary branches and these, in turn, could divide up to 6 times in tertiary branches that penetrated in the muscle. The biometric knowledge of the origin of the nerve of the ECRLm, as well as its distribution, is an important contribution to the anatomo-surgical area, as well as its use in nerve blocks, nerve transfers and electrode placement areas for purposes of electrical stimulation in patients they need to rehabilitate the action of injured radial extensor musculature.

Localización biométrica de los puntos motores en el músculo tríceps braquial de individuos brasileños / Biometric location of motor points in the brachial triceps muscle of Brazilian individuals

RESUMEN: El músculo tríceps braquial, es el motor primario para el movimiento de extensión de codo, por lo que una lesión que afecte su función perjudicaría enormemente la calidad de vida de los afectados. El conocimiento de su inervación y la localización biométrica de sus puntos motores, es una herramienta útil en terapias de electro estimulación muscular. El objetivo del estudio fue determinar el número y localización de los puntos motores de este músculo. Para ello, se utilizaron 30 miembros superiores de individuos brasileños, a los cuales se les realizó una disección detallada del compartimiento posterior del brazo. Se registró el número de ramos, puntos motores y localización biométrica de cada uno de los ramos destinados a las cabezas del músculo triceps braquial. Se utilizó como punto de referencia una Línea biepicondilar, trazada entre los epicóndilos humerales. En todos los casos este músculo estaba inervado por el nervio radial. El promedio de puntos motores (PM) para la cabeza larga del músculo (CL) fue de 3,9 ± 1,4; 4,8 ± 1,2 para la cabeza medial (CM) y 4,1 ± 1,4 para la cabeza lateral (CLat). Los puntos motores se concentraron preferentemente en el tercio medio del brazo, tanto a nivel general, como también por cada cabeza. Los datos biométricos aportados complementarán el conocimiento de la inervación de este músculo y favorecerá una mejor comprensión y elección de tratamientos frente a una patología.

SUMMARY: The triceps brachii muscle is the primary motor for elbow extension movement, so a lesion that affects its function would greatly harm the quality of life of those affected. The knowledge of its innervation and the biometric localization of its motor points is a useful tool in electro-stimulation muscular therapies. The objective of the study was to determine the number of branches and location of the motor points of this muscle. To this end, 30 superior members of Brazilian individuals were used, to whom a detailed dissection of the posterior compartment of the arm was performed. The number of branches, motor points and biometric location of each of the branches destined for the three heads of the brachial triceps muscle was recorded. A biepicondilar line, traced between the humeral epicondyles, was used as a reference point. In all cases, this muscle was innervated by the radial nerve. The average motor points for the long head of the muscle (LH) was 3.9 + 1.4; for the medial head (MH) was 4.8 + 1.2 and for the lateral head (LatH) was 4.1+1.4. The motor points were concentrated mainly in the middle third of the arm, both at a general level, and also for each head. The biometric data provided will complement the knowledge of the innervation of this muscle and will favor a better understanding and choice of treatments for a pathology.

The course and branching patterns of the superficial branch of radial nerve in foetuses and clinical significance / Curso y patrones de ramificación del ramo superficial del nervio radial en fetos y su importancia clínica

Knowing the anatomical, topographic and morphometric properties of the superficial branch of the radial nerve (SBRN) in the forearm and the dorsum of the hand is important for minimizing nerve damage. The purpose of this study is to evaluate the anatomical and morphometric properties of SBRN in foetuses. Forty forearms of twenty-one foetuses (n=21) were dissected. The anatomical variations of SBRN in the dorsal forearm were assessed in three types (Type-1, Type-2 and Type-3). The innervation areas in dorsum of hand were assessed in four types (Type-1, Type-2, Type-3 and Type-4). The forearm length was divided to three part and emerging point of SBRN was determined as topographically. The relation of the SBRN with lateral antebrachial cutaneous nerve (LACN), anatomic snuffbox and cephalic vein was also evaluated. In forearm, Type-1 variation rate of SBRN was 87.5 %. In the dorsum of hand, Type-3 innervation pattern was 32.5 %. The emerging rate of SBRN in the middle third of the forearm was 74.4 %. There were nerve branches between LACN and SBRN or its terminal branches in 32.5 % of the forearms. The branches of SBRN passed within the margins of anatomic snuffbox in 50 % of the forearms. The most frequently branching type of SBRN was Type-1 in the forearm and Type-3 in the dorsum of hand in foetuses. These results may aid to minimize nerve injuries performed in clinical applications.

Conocer las propiedades anatómicas, topográficas y morfométricas del ramo superficial del nervio radial (RSNR) en el antebrazo y el dorso de la mano es importante para minimizar el daño a los nervios. El propósito de este estudio fue evaluar las propiedades anatómicas y morfométricas de RSNR en fetos. Fueron disecados 40 antebrazos de veintiún fetos. Las variaciones anatómicas de RSNR en el dorso del antebrazo se clasificaron en tres tipos (Tipo-1, Tipo-2 y Tipo-3). Las áreas de inervación en el dorso de la mano se evaluaron en cuatro tipos (Tipo 1, Tipo 2, Tipo 3 y Tipo 4). La longitud del antebrazo se dividió en tres partes y el punto emergente de RSNR se determinó topográficamente. Se evaluó la relación del RSRN con el nervio cutáneo antebraquial lateral (NCAL), la tabaquera anatómica y la vena cefálica. En el antebrazo, la tasa de variación de Tipo 1 de RSNR fue de 87,5 %. En el dorso de la mano, el patrón de inervación tipo 3 fue del 32,5 %. La emergencia del RSNR en el tercio medio del antebrazo fue de 74,4 %. En el 32,5 % de los antebrazos se observaron ramos nerviosos entre NCAL y RSNR. Los ramos de RSNR pasaron dentro de los límites de la tabaquera anatómica en 50 % de los antebrazos. El tipo de RSNS con ramificación más frecuente fue el Tipo 1 en el antebrazo y el Tipo 3 en el dorso de la mano en los fetos. Conocer las variaciones anatómicas de RSNS puede ayudar a minimizar las lesiones nerviosas durante los procedimientos clínicos.

Inervación del músculo extensor radial corto del carpo en individuos brasileños: biometría de su origen y distribución / Innervation of the extensor carpi radialis brevis muscle in Brazilian individuals: biometry of its origin and distribution

El ramo de inervación para el músculo extensor radial corto del carpo (MERCC) ha sido utilizado para restablecer funciones de la musculatura del miembro superior en pacientes con lesiones medulares, del plexo braquial o de sus ramos terminales. El origen del nervio para el MERCC es variable, pudiendo originarse desde el tronco del nervio radial (NR), del ramo profundo de este nervio (RPNR) o del ramo superficial del mismo (RSNR). Con el propósito de complementar la anatomía sobre el origen y distribución del ramo para el MERCC, se utilizaron 30 miembros superiores, formolizados, de cadáveres de individuos Brasileños, localizados en los laboratorios de Anatomía de la Universidad Estadual de Ciencias da Saude, Maceió, Brasil. A través de disección se localizó el músculo y su inervación, determinando su origen, así como su distribución. Para efectuar la biometría, se consideró como referencia una línea transversal que pasaba entre las partes más prominentes de los epicóndilos lateral y medial del húmero (LBE), registrando la distancia entre esta línea y el punto de origen de este ramo muscular, así como la distancia entre la LBE y los puntos motores. El nervio para el MERCC se originó del RPNR en 50 % de los casos; desde el tronco principal del NR en 26, 7 % y desde el RSNR en 23, 3 %. La distancia entre el origen del ramo en estudio y la LBE fue en promedio de 23 ± 12 mm; la distancia entre el 1º, 2º y 3º punto motor respecto a la LBE fue de 55 ± 17 mm, 66 ± 17 mm y 79 ± 11 mm, respectivamente. La distribución de la inervación fue clasificada en 4 tipos en relación a sus puntos motores. Los resultados obtenidos son un importante aporte al conocimiento anatómico, así como a la neurocirugía en las transferencias nerviosas con propósitos de restauración de las funciones de músculos lesionados en el miembro superior.

The branch of the innervation for the extensor carpi radialis brevis muscle (ECRBm), has been used to reestablish muscle functions in the upper limbs of patients who have spinal cord injury, of the brachial plexus or its terminal branches. The origin of the ECRBm varies, and can originate from the trunk of the radial nerve (RN), from the deep branch of the radial nerve (DBRN), or from the superficial branch of the radial nerve (SBRN). In order to further complement the anatomy related to the origin and distribution of the ECRBm branch, 30 formolized upper limbs from Brazilian individuals, from the Universidad Estadual de Ciencias da Saude, Maiceió, Brazil were used. Through dissection, the muscle and its innervations was located, determining the origin of the branch as well as distribution. To determine biometry, a transversal reference line, which passed through the most prominent areas of the epicondyles of the humerus (BEL) was considered. The nerve for ECRBm originated from DBRN in 50 % of cases; from the main trunk of RN in 26.7 % and from SBRN in 23.3 %. The distance from the origin of the branch studied and the BEL was an average of 23 ± 12 mm; the distance from the first, second and third motor point to the BEL was 55 ± 17 mm, 66 ± 17 mm and 79±11 mm, respectively. The distribution of the innervation was classified in four types in relation to the motor points. The results are an important contribution to anatomical knowledge, as well as neurosurgery during nerve transfers to restore functions of damaged muscles in the upper limb.

Biometría del musculo tríceps braquial y de sus puntos motores: un estudio anatómico directo en una muestra de población colombiana / Biometry of the brachial triceps muscle and its motor points: a direct anatomical study in a sample of colombian population

Las características anatómicas del músculo tríceps braquial (MTB) determinan la velocidad de reparación y capacidad de generación de torque. El MTB es inervado típicamente por el nervio radial (NR), pero existen reportes de inervación por parte del nervio axilar. El propósito de este estudio fue evaluar los componentes musculotendinosos y nerviosos del MTB. Mediante disección directa en una muestra de 48 brazos de población mestiza colombiana, se evaluó morfometría musculotendinosa, ramos nerviosos, puntos motores (PM) y origen de la inervación del MTB. Las longitudes de las cabezas medial, lateral y larga del MTB correspondieron al 77,3 %, 86 % y 97 % respectivamente de la longitud del brazo. El MTB fue inervado en la totalidad de la muestra por el NR quien emitió entre dos y cinco ramos motores. El primer ramo inervó la cabeza larga en el 100 % de los casos y emergió lateral a la banda tendinosa de inserción del músculo latísimo del dorso. La cabeza larga recibió con mayor frecuencia tres PM (26,6 %), ubicados en el 85 % de los especímenes a 4-10 cm del origen muscular; mientras que la cabeza lateral recibió tres PM en el 44,4 % de la muestra. No hubo diferencias estadísticamente significativas entre el número de PM del MTB izquierdo con relación al derecho (p=0,578). El área de dispersión de PM, así como la morfometría del MTB, son de relevancia clínica, debido a su uso en la estimulación eléctrica neuromuscular y transferencias nerviosas. Los resultados presentados en el presente estudio se constituyen en guía que facilita realizar estas acciones terapéuticas.

The anatomical characteristics of the triceps brachii (TBM) muscle determine the repair speed and torque generation capacity. The TBM is typically innervated by the radial nerve (RN), but there are reports of innervation by the axillary nerve. The aim of this study was to evaluate musculotendinous and nervous components of TBM. Through direct dissection in a sample of 48 arms of the Colombian mestizo population, we evaluated musculotendinous morphometry, nerve branches, motor points (MP) and origin of TBM innervation. The lengths of the medial, lateral and long heads of the TBM corresponded to 77.3 %, 86 % and 97 % of the arm length respectively. The TBM was innervated in the whole sample by the NR who issued between two and five motor branches. The first branch innervated the long head in 100 % of cases and emerged laterally to the tendinous band insertion of the latissimus dorsi muscle. The long head received three MP (26.6 %), located in 85 % of the specimens at 4 - 10 cm of muscular origin; while the lateral head received three MP in 44.4 % of the sample. There were no statistically significant differences between the number of MP of the left TBM in relation to the right (p = 0.578). The dispersion area of MP, as well as TBM morphometry are clinically relevant due to their use in neuromuscular electrical stimulation and nerve transfers. The findings presented in this study are a guide to facilitate results in this type of therapeutic action.

Anatomical factors/countermeasures in/against iatrogenic injury of the deep branch of radial nerve in the Thompson approach via middle and proximal segments of forearm / Factores anatómicos/contramedidas en/contra la lesión iatrogénica del ramo profundo del nervio radial en el abordaje de Thompson a través de los segmentos medio y proximal del antebrazo

This study aimed to investigate the anatomical factors affecting iatrogenic injury of the deep branch of radial nerve during the Thompson approach and to propose corresponding countermeasures. Thompson approach was used to measure the horizontal/longitudinal distance from the position where the deep branch of radial nerve leaves the supinator to the ulnar margin of extensor carpi radialis brevis/humeroradial joint line. Measurements were obtained by using 48 adult cadaver specimens, which were used in teaching. We observed the lentor situation of the extensor digitorum and extensor carpi radialis brevis in proximal forearm segments and measured the distance from the deep branch of radial nerve to the humeroradial joint line at the lateral side of the radius in the neutral position of forearm rotation. The horizontal distance from the point where the deep branch of radial nerve leaves the inferior margin of supinator to the ulnar margin of extensor carpi radialis brevis was 1.3 ± 0.3 cm. The distance to the humeroradial joint line was 61.3 ± 17.6 mm. The distance to the lentor extent of extensor digitorum and extensor carpi radialis brevis at the distal part of humeroradial joint was 7.1 ± 2.1 cm. The distance from the deep branch of radial nerve to the humeroradial joint line at the lateral side of the radius is 3.2 ± 0.6 mm. Anatomical factors are observed in iatrogenic injury of the deep branch of radial nerve during the Thompson approach. Stretching the extensor digitorum before the dissection of the supinator is hazardous.

El objetivo de este estudio fue investigar los factores anatómicos que provocan la lesión iatrogénica del ramo profundo del nervio radial durante el abordaje de Thompson y proponer las contramedidas correspondientes. El abordaje de Thompson se utilizó para medir la distancia horizontal / longitudinal desde la posición en que el ramo profundo del nervio radial sale del músculo supinador hasta el margen ulnar del músculo extensor radial corto del carpo a nivel de la línea articular humeroradial. Las mediciones se obtuvieron utilizando 48 especímenes de cadáveres adultos, que se usaron en la enseñanza. Se observó la situación de los músculos extensor de los dedos y del extensor radial corto del carpo en los segmentos proximales del antebrazo y se midió la distancia desde el ramo profundo del nervio radial hasta la línea articular humeroradial en el margen lateral del radio en posición neutra de rotación del antebrazo. La distancia horizontal desde el punto en que el ramo profundo del nervio radial sale del margen inferior del músculo supinador hasta el margen ulnar del músculo extensor radial corto del carpo fue 1,3 ± 0,3 cm. La distancia a la línea articular humeroradial fue de 61,3 ± 17,6 mm. La distancia entre el músculo extensor de los dedos y el músculo extensor radial corto del carpo en la parte distal de la articulación humeroradial fue de 7,1 ± 2,1 cm. La distancia desde el ramo profundo del nervio radial a la línea articular humeroradial en el lado lateral del radio fue de 3,2 ± 0,6 mm. Se observan factores anatómicos en la lesión iatrogénica del ramo profundo del nervio radial durante el abordaje de Thompson. El estiramiento del extensor de los dedos antes de la disección del músculo supinador es peligroso.

Anatomical Snuffbox and it Clinical Significance: A Literature Review / La Tabaquera Anatómica y su Importancia Clínica: Una Revisión de la Literatura

The anatomical snuffbox is a small triangular area situated in the radial part of the wrist, often used to perform clinical and surgical procedures. Despite the frequency with which this area is used, there is scarce information in literature about its details. The objective of this study is detailed knowledge of the anatomical snuffbox's anatomy and its components, the reported alterations at this portion, besides the clinical uses and significance of this area.

La tabaquera anatómica, es una pequeña área triangular ubicada en la parte radial de la muñeca utilizada a menudo para realizar procedimientos clínicos y quirúrgicos. A pesar de la frecuencia con la que se utiliza esta zona, escasea la información acerca de sus detalles en la literatura. El objetivo de este estudio es conocer con detalle la anatomía de la tabaquera anatómica y sus componentes, las alteraciones reportadas a ese nivel, y los usos e importancia clínica de esta región.

Topographic and biometric study of radial nerve branches to the muscles of the anterior compartment of the arm / Estudio topográfico y biométrico de los ramos del nervio radial para los músculos del compartimiento anterior del brazo

The radial nerve is a terminal branch of the brachial plexus that innervates the entire posterior compartment of the upper limb. Researches have shown that the branches can contribute to innervation of the muscles from the anterior compartment of the arm. This study sought to identify branches of radial nerve for brachialis and coracobrachialis muscles and its clinical value during surgery. Dissection was performed in 60 arms, from 30 corpses selected from the Human Anatomy Laboratories of Universidade Estadual de Ciências da Saúde de Alagoas (UNCISAL). In each arm, three segments of the same proportion were considered (proximal, middle and distal) in order to observe the number of radial nerve branches to brachialis and coracobrachialis muscles. Branches were identified in 4 of the 60 upper limb (6.66%) with the following distribution: nerve with 1 branch to the brachialis muscle in the distal third (1.66%); with 1 branch to the middle third of the coracobrachialis (1.66%) and 5 branches to the coracobrachialis muscle in the proximal third; 1 branch being found in an upper limb (1.66 %) and 4 branches in the other upper limb (1.66 %). The event was not bilaterally in the same body, and in four cases there was no branching, but only communication with other terminal nerves of the brachial plexus. In conclusion, although most authors do not describe the possibility of the occurrence of radial nerve branches to the muscles of the anterior compartment of the arm, this condition exists as an anatomical variation.

El nervio radial es un ramo terminal del plexo braquial que inerva el compartimiento posterior del miembro superior. Diversos estudios han mostrado que sus ramos pueden contribuir a la inervación de los músculos del compartimiento anterior del brazo. El presente estudio tuvo como objetivo identificar ramos del nervio radial dirigidos a los músculos braquial y coracobraquial y su importancia clínica durante las cirugías. Para ello, se disecaron 60 brazos de 30 cuerpos formolizados en los Laboratorios de Anatomía Humana de la Universidad Estadual de Ciencias de la Salud de Alagoas, Brasil (UNCISAL). En cada brazo, se consideraron tres partes de similares proporciones (proximal, medio y distal) para localizar los ramos dirigidos a los músculos mencionados. En 4 de los 60 brazos (6,66%) se identificaron ramos con la siguiente distribución: un ramo para el músculo braquial en el tercio distal (1,66%); un ramo para el tercio medio del músculo coracobraquial (1,66%) y cinco ramos para este mismo músculo en su tercio proximal; en otro miembro (1,66%)se encontró solo un ramo y en la otra muestra (1,66%) se encontraron cuatro ramos. Ninguno de los casos fue bilateral y en los cuatro casos no había ninguna ramificación. No hubo comunicación con el nervio musculocutáneo pero si con otros ramos del plexo braquial. Aunque la mayoría de los autores no describe la posibilidad de que el nervio radial inerve a los músculos anteriores del brazo, esta disposición existe como una variación anatómica.