Anatomical and histomorphometric study of the ulnar nerve at the wrist / Estudio anatómico e histomorfométrico del nervio ulnar en la muñeca

SUMMARY: The ulnar nerve (UN) is the main nerve responsible for innervation of the intrinsic musculature of the hand. It is of great importance to have a deep anatomical knowledge of the UN. The aim of this study is to enrich the knowledge of the UN anatomy at the wrist and provide useful reference information for clinical and surgical applications. In this descriptive cross-sectional study, 44 upper limbs of fresh cadavers were evaluated. The UN, the superficial branch of the ulnar nerve (SBUN), and the deep branch of the ulnar nerve (DBUN) were evaluated. Morphometric variables were measured using a digital caliper, and samples of nervous tissue were taken to evaluate the histomorphometry. Before entering the Guyon's canal, the UN had a diameter of 3.2 ± 0.4 mm. In 36 samples (82 %) the UN presented a bifurcation pattern and in the remaining 8 samples (18 %) a trifurcation was shown. The diameter of the DBUN was 1.9 ± 0.33 mm and that of the SBUN was 1.29 ± 0.22 mm. In the bifurcation patterns, the SBUN had a trunk of 5.71 ± 1.53 mm before bifurcating into the common digital nerve (fourth and fifth fingers) and an ulnar digital collateral nerve (fifth finger). The DBUN had an area of 2.84 ± 0.7 mm2 and was made up of 8 ± 1.4 fascicles and 3595 ± 465 axons. The SBUN area was 1.31 ± 0.27 mm2, it was made up of 6 ± 1.1 fascicles and 2856 ± 362 axons. The reported findings allow the hand surgeon to improve his understanding of the clinical signs of patients with UN pathologies at the wrist level and thus achieve greater precision while planning and performing surgical approaches and dissections.

El nervio ulnar (NU) es el principal nervio responsable de la inervación de la musculatura intrínseca de la mano. Es de gran importancia tener un profundo conocimiento anatómico del NU. El objetivo de este estudio fue enriquecer el conocimiento de la anatomía del NU en la muñeca y proporcionar información de referencia útil para aplicaciones clínicas y quirúrgicas. En este estudio descriptivo transversal se evaluaron 44 miembros superiores de cadáveres frescos. Se evaluó el NU, el ramo superficial del nervio ulnar (RSNU) y el ramo profundo del nervio ulnar (RPNU). Las variables morfométricas se midieron con un caliper digital y se tomaron muestras del nervio para evaluar la histomorfometría. Antes de ingresar al canal del nervio ulnar (canal Guyon), el ONU tenía un diámetro de 3,2 ± 0,4 mm. En 36 muestras (82 %) el ONU presentó un patrón de bifurcación y en las 8 muestras restantes (18 %) se presentó una trifurcación. El diámetro del RPNU fue de 1,9 ± 0,33 mm y el del RSNU de 1,29 ± 0,22 mm. En los patrones de bifurcación, el RSNU presentó un tronco de 5,71 ± 1,53 mm antes de bifurcarse en el nervio digital común (cuarto y quinto dedo) y un nervio digital colateral ulnar (quinto dedo). El RPNU tenía un área de 2,84 ± 0,7 mm2 y estaba formado por 8 ± 1,4 fascículos y 3595 ± 465 axones. El área del RSNU fue de 1,31 ± 0,27 mm2, estaba formado por 6 ± 1,1 fascículos y 2856 ± 362 axones. Los hallazgos reportados permiten al cirujano de mano mejorar su comprensión de los signos clínicos de los pacientes con patologías del NU a nivel de la muñeca y así lograr una mayor precisión en la planificación y realización de abordajes y disecciones quirúrgicas.

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.

Anatomical study of the transfer of flexor digitorum superficialis nerve branch of median nerve to restore wrist extension and forearm pronation / Estudo anatômico da transferência do ramo do nervo mediano destinado ao músculo flexor superficial dos dedos para restaurar a extensão do punho e a pronação do antebraço

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

RESUMO Objetivo Analisar as variações anatômicas da inervação do músculo flexor superficial dos dedos e determinar se o ramo do nervo mediano destinado a esse músculo pode ou não ser conectado aos ramos para os músculos extensor radial curto do carpo e pronador redondo sem tensão, e quão próximo dos músculos-alvo a transferência pode ser realizada. Métodos Foram dissecados 50 membros de 25 cadáveres para coletar dados sobre as variações anatômicas dos ramos para o músculo flexor superficial dos dedos. Resultados O referido músculo recebeu inervação do nervo mediano nos 50 membros. Em 22 recebeu um ramo, em 28 mais que um. O ramo proximal foi identificado em 22 membros e em 12 compartilhava ramos com outros músculos. O ramo distal estava presente em todos e desprendeu-se do nervo mediano como um ramo isolado ou de um tronco comum com o nervo interósseo anterior em 3 membros, e de um tronco comum com músculo flexor radial do carpo e nervo interósseo anterior em outro. Originou-se distalmente ao nervo interósseo anterior em 38, em 5 no mesmo nível e em 3 proximal ao nervo interósseo anterior. Em quatro recebeu inervação do nervo interósseo anterior, além daquela recebida pelo mediano. Ramos acessórios do nervo mediano para a porção distal do músculo flexor superficial dos dedos estavam presentes em oito membros. Conclusão Nos 28 membros em que existam 2 ou mais ramos, 1 desses poderia ser conectado aos ramos para o músculo extensor radial curto do carpo e pronador redondo sem tensão, mesmo durante os movimentos de pronossupinação do antebraço e flexão-extensão do cotovelo.

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.

Flexor zone 5 cut injuries: emergency management and outcome

To determine the outcome and devise a protocol for emergency management of cut injuries in Flexor Zone 5 of hands. Descriptive study. Department of Plastic Surgery and Burn Unit, Mayo Hospital, KEMU, Lahore, Pakistan, from January 2009 to March 2013. All patients above 12 years of age with single sharp cut injuries in Flexor Zone 5, with no skeletal injuries, presenting within 12 hours in emergency were included with follow-up of 6 months, with active range of motion evaluated by Strickland's adjusted formula. Power of opponens pollicis and adductor muscles was evaluated from P0-4. Nerve repair results were evaluated serially by advancing Tinnel's sign, electrophysiological studies and sensory perception scored from S0-4 compared to the normal opposite upper limb. The study group comprised of 31 patients [M: F = 2.4: 1]. Average age was 27 years ranging from 17 - 53 years. In 25 [80%] cases, injury was accidental, in 3 [10%] homicidal and in 3 [10%] injury was suicidal. Four most commonly involved structures included Flexor carpi ulnaris, ulnar artery, ulnar nerve and Flexor digitorum superficialis. Median nerve and radial artery were involved in 10 cases each, while ulnar artery and ulnar nerve were involved in 14 cases each. Longtendons were involved in most cases with greater involvement of medial tendons. None of the patients required re-exploration for ischaemia of distal limb while doppler showed 22 out of 24 vascular anastomosis remained patent. Recovery of long-tendons was good and recovery after nerve repair was comparable in both median and ulnar nerves. Early and technically proper evaluation, exploration and repair of Zone 5 Flexor tendon injuries results in good functional and technical outcome

Arteria mediana persistente (AMP) bilateral de gran calibre en sujeto asintomático / High-caliber persistent bilateral median artery in asymptomatic

Se describe hallazgo en hombre de 22 años, asintomático, sano, de Arteria Mediana Persistente (AMP) bilateral de gran calibre asociada a un nervio median bífido (NMB) en una de las muñecas. La arteria mediana puede persistir hasta la adultez, acompañando al nervio por el túnel carpiano. Es una variante frecuente, suele ser bilateral y se asocia usualmente a NMB. La presencia de AMP puede asociarse a STC agudo secundario a trombosis y a STC crónicos por conflicto espacial. Sorprende el carácter asintomático de nuestro paciente a pesar del gran calibre de sus AMP. Sugerimos realizar, previo a cirugía o infiltración por STC, una ultrasonografía para adaptar tratamiento y evitar complicaciones.

We describe two high-caliber persistent median arteries (MPA) in an asymptomatic 22 year old healthy man, one of them between a bifid median nerve (BMN). The median artery may persist into adulthood, accompanying the median nerve through the carpal tunnel. It is a frequent anatomic variant, usually bilateral, regularly associated to BMN. The presence of MPA may be associated with acute carpal tunnel syndrome (CTS) secondary to thrombosis and chronic CTS probably due to spatial conflict. In this case, calls attention the lack of symptomatology despite the great size of MPA. We suggest performing prior to any surgery or infiltration of corticosteroids for CTS, an ultrasonographic study to avoid surgical complications.

Analysis of MR imaging of wrists in female patients with carpal tunnel syndrome and healthy controls / Análisis de imágenes de RM de las muñecas en pacientes mujeres con síndrome del túnel carpiano y controles sanos

The objective of this study was to evaluate morphological changes of the median nerve in patients with carpal tunnel syndrome (CTS) and healthy controls, to correlate the MRI findings of wrists. This study compared not only morphological changes of the median nerve and also displayed descriptively structures in carpal tunnel between patients diagnosed with idopathic CTS and healthy controls. Our study involved 60 hand, 30 of hand were evaluated diagnosed with idiopathic CTS and 30 hand as healthy controls bilaterally. Two provocative tests (Phalen's and Tinel's test) were performed on each hand for both the patient group (60 wrist) and the control group (60 wrist). With regard to Phalen and Tinel's test results, 24 and 26 wrists were excluded from patient and control groups respectively. Totally 70 wrists were evaluated, and in terms of cross-sectional area of median nerve at the level of distal radio-ulnar joint, pisiform bone and the hook of hamate bone by MRI in the patient and control groups. In addition to evaluation of cross-sectional area of median nerve, we determined signal intensity of wrists and different localization of the median nerve in the carpal tunnel. Cross-sectional area of the median nerve measured by wrist magnetic resonance at the level of metacarpal bones and signal intensity of wrists may be considered as a valuable indicator to determine patients referred with idiopathic CTS.

El objetivo de este estudio fue evaluar los cambios morfológicos del nervio mediano en pacientes con síndrome del túnel carpiano (STC) y controles sanos, para correlacionar los hallazgos de las RM de muñeca. Este estudio comparó no sólo los cambios morfológicos del nervio mediano, también se muestran en forma descriptiva estructuras del túnel carpiano entre los pacientes diagnosticados con STC idiopatico y controles sanos. Nuestro estudio incluyó 60 manos, 30 manos fueron evaluados con diagnóstico de STC idiopático y 30 manos como controles sanos, bilateralmente. Dos pruebas de provocación (prueba de Phalen y prueba de Tinel) se realizaron en cada mano para el grupo de pacientes (60 muñecas) y el grupo control (60 muñecas). En lo que respecta a los resultados de prueba de Phalen y prueba de Tinel, 24 y 26 muñecas fueron excluidas del grupo paciente y grupo control respectivamente. En total 70 muñecas fueron evaluadas, en términos de la sección transversal del área del nervio mediano a nivel de la articulación radio-ulnar distal, el hueso pisiforme y el hamulus del hueso hamate por medio de resonancia magnética en gruposs paciente y control. Además de la evaluación de la sección del área del nervio mediano, se determinó la intensidad de la señal de la muñeca y las diferentes localizaciones del nervio mediano en el túnel carpiano. La sección transversal del área del nervio mediano medida por medio de resonancia magnética de muñeca a nivel de los huesos metacarpianos y la intensidad de la señal de las muñecas pueden ser considerados como un valioso indicador al evaluar pacientes referidos con STC idiopático.

Parámetros biométricos y morfometría de la porción terminal del nervio mediano, ramo superficial del nervio ulnar y nervios digitales palmares comunes de la mano humana / Biometric and morphometric parameters of the terminal end of the median nerve, superficial branch of the ulnar nerve and common palmar digital nerves in the human hand

El conocimiento de la distribución de los nervios de la mano es necesario para realizar un adecuado diagnóstico de lesiones que le afectan y para realizar con efectividad la recuperación o reconstrucciones de la misma. Basados en esta premisa, se realizó un estudio biomorfométrico de la porción terminal del nervio mediano (NM), del ramo superficial del nervio ulnar (RSnU) y de los nervios digitales palmares comunes (NDPC). Se utilizó para ellos, 12 manos de cadáveres de individuos chilenos, adultos, pertenecientes a los Laboratorios de Anatomía, Facultad de Medicina, Universidad de La Frontera, Chile. Se realizó disección convencional y los registros morfométricos se efectuaron en 5 manos, de las cuales se extrajeron muestras y se trataron con técnicas histológicas adecuadas. Las distancias promedio entre el pliegue distal de la muñeca y el punto de división del NM, y, entre el mismo pliegue y la división del RSnU fueron de 35,5 y 26,1 mm, respectivamente; las distancias promedio entre el pliegue mencionado y el punto de división de los NDPC I, II, III y IV, fueron de 43,5; 68,1; 72,6 y 66,1 mm, respectivamente. Los diámetros externos promedios de estos últimos nervios fueron de 3,25; 1,92; 2,24 y 1,73, respectivamente. El número de fascículos del NM antes de su división fue en promedio de 30, del RSnU de 16,8; del NDPC I de 11,8; del NDPC II de 15,4; del NDPC III de 14,6 y del NDPC IV de 12,4. El número de fibras del NM antes de su división fue en promedio de 22.565, del RSnU de 8.835, del NDPC I de 4.859, del NDPC II de 5.767, del NDPC III de 5.233 y del NDPC IV de 3.606. Estos resultados aportan nuevos antecedentes para la clínica, cirugía y anatomistas, complementando el tema de la inervación de la mano.

It is necessary to know the distribution of the nerves in the hand in order to make a suitable diagnosis of the injuries that affect it and to effectively implement recovery or reconstructions. Based on this premise, a biomorphometric study was conducted on the terminal end of the median nerve (MN), the superficial branch of the ulnar nerve (SBUN) and the common digital palmar nerves (CDPN). 12 hands of adult cadavers Chileans housed in the Anatomy Laboratones in the Faculty of Medicine at the University de La Frontera, Chile were used for this purpose. 5 hands were dissected by conventional means and registered morphometricaily, from which samples were taken and treated using the appropriate histological techniques. The average distance between the distal wrist crease and the division of the MN, and between the same crease and the division for the SBUN was 35.5 and 26.1 mm, respectively; the average distances between the crease mentioned and the division of CDPN I, II, III and IV were 43.5, 68.1, 72.6 and 66.1 mm, respectively. The average external diameters of these latter nerves were 3.25, 1.92, 2.24 and 1.73, respectively. The average number fascicles prior to division was 30 from the MN, 16.8 from the SBUN, 11.8 from the CDPN I, 15.4 from CDPN II, 14.6 from CDPN III and 12.4 from CDPN IV. The average number of fibers prior to division was 22565 from the MN, 8835 from the SBUN; 4859 from the CDPN I, 5767 from the CDPN II, 5233 from the CDPN III and 3606 from the CDPN IV. These results will provide new support for clinicians, surgeons and anatomists, complementing the topic of innervation of the hand.

Estudio anatómico de las inserciones de los músculos extensores radiales largo y corto del carpo / Anatomical study of insertion of the extensor carpi radialis longus and brevis

En el análisis de los tendones de los músculos extensores radiales largo y corto del carpo, basados en la disección anatómica de 60 miembros superiores de cadáveres adultos de raza blanca y sexo masculino, registramos que las variaciones anatómicas no son muy frecuentes. La presencia de tendones accesorios ocurrió en apenas 3 manos disecadas, todas del músculo extensor radial largo del carpo. La presencia de vínculos tendinosos uniendo los tendones, fue registrada en 17 piezas. La presencia de un tendón intermedio uniendo los dos tendones, fue verificada en 4 piezas. La inserción del tendón del músculo extensor radial largo del carpo ocurrió, invariablemente, en el lado radial de la base del segundo metacarpiano y del músculo extensor radial corto en el lado radial de la base del tercer metacarpiano.Basados en nuestras disecciones podemos afirmar que la conformación anatómica normal de los músculos extensores radiales largo y corto del carpo, es la presencia de un cuerpo muscular y un tendón de cada uno de los músculos extensores radiales que son cubiertos por los músculos abdutor largo y extensor corto; pasan por el segundo compartimiento dorsal del puño y se insertan, el músculo extensor radial largo en el lado radial de la base del segundo metacarpiano y el músculo extensor radial corto en el lado radial de la base del tercer metacarpiano, invariablemente.

Surgical management of Guyon's canal syndrome, an ulnar nerve entrapment at the wrist: report of two cases

Guyon's canal syndrome, an ulnar nerve entrapment at the wrist, is a well-recognized entity. The most common causes that involve the ulnar nerve at the wrist are compression from a ganglion, occupational traumatic neuritis, a musculotendinous arch and disease of the ulnar artery. We describe two cases of Guyon's canal syndrome and discuss the anatomy, aetiology, clinical features, anatomical classification, diagnostic criteria and treatment. It is emphasized that the knowledge of both the surgical technique and anatomy is very important for a satisfactory surgical result