ABSTRACT
SUMMARY: There is evidence demonstrating the presence of functional compartmentalisation (FC) in some skeletal muscles. This means that the motor units (MU), grouped in certain areas of the muscle, show different levels of activation in comparison to those located in other zones. This has only been described in large muscles whose morphology proves the existence of a FC. However, there is no background information about small muscles, such as the Abductor digiti minimi manus (ADM). The objective of this study was to compare the activation of the MU in different zones of the ADM to support the hypothesis of the existence of a FC in the ADM. By using a cross- sectional, analytical, observational study, the activity of the MUs in the ADM was assessed in 12 volunteers (age 21 ± 1.6 years old; weight 75.3 ± 8 kg; height 176.2 ± 7.3 cm; average ± standard deviation). The activity of MUs was evaluated using high-density surface electromyography (HD-sEMG) with an array of 64 electrodes arranged two-dimensionally. This allowed us to record the activity of the MUs in three zones of the ADM (Z1: dorsal zone; Z2: dorsal-palmar zone and Z3: palmar zone). Electromyographic recordings were obtained during voluntary isometric contractions of the ADM at 20, 40, 60 and 80 % of the maximum voluntary contraction (MVC). The comparison of the activation levels of MUs between the three zones was carried out using a mixed model analysis of covariance. The results showed a significant difference between the dorsal and palmar zones at 40 % of the MVC (p= 0.03), and between the dorsal and dorsal- palmar zone at 80 % of the MVC (p= 0.03). The results obtained in the evaluated sample support the hypothesis of the existence of FC in the ADM. However, further research is needed to determine with greater certainty the presence of this compartmentalisation in the ADM.
RESUMEN: Existe evidencia que demuestra la presencia de una compartimentalización funcional (CF) en algunos músculos esqueléticos. Aquello se traduce en que las unidades motoras (UM) agrupadas en ciertas zonas del músculo, presentan diferentes niveles de activación a las ubicadas en otras regiones. Esto solo ha sido descrito en músculos grandes, cuya morfología justifica la existencia de una CF. Sin embargo, no existen antecedentes de aquello en músculos pequeños, tales como el abductor digiti minimi manus (ADM). El objetivo de este estudio fue comparar la activación de las UM en distintas zonas del ADM, con la finalidad sostener la hipótesis de la existencia de una CF en el ADM. Mediante un estudio observacional analítico transversal se evaluó la actividad de las UM del ADM en 12 voluntarios (edad 21±1,6 años; peso 75,3±8 kg; altura 176,2 ± 7,3 cm; promedio ± desviación estándar). La actividad de las UM, se evaluó mediante electromiografía de superficie alta densidad usando una matriz de 64 electrodos dispuestos bidimensionalmente. Esta permitió registrar la actividad de las UM en tres zonas del ADM (Z1: zona dorsal; Z2: zona dorso-palmar y Z3: zona palmar). Los registros electromiográficos fueron obtenidos durante contracciones isométricas voluntarias del ADM al 20, 40, 60 y 80 % de la contracción voluntaria máxima (CVM). La comparación de los niveles de activación de las UM entre las tres zonas fue realizada mediante un análisis de modelos mixtos de covarianza. Los resultados indicaron que existió diferencia significativa entre la zona dorsal y palmar al 40 % de la CVM (p=0,03), y entre la zona dorsal y dorso-palmar al 80 % de la CVM (p=0,03). Los resultados obtenidos en la muestra evaluada sostienen la hipótesis de la existencia de una CF en el ADM. Sin embargo, son necesarias más investigaciones para establecer con mayor certeza la presencia de esta compartimentalización en el ADM.
Subject(s)
Humans , Young Adult , Muscle, Skeletal/anatomy & histology , Electromyography/methods , Hand/anatomy & histology , Cross-Sectional Studies , Muscle, Skeletal/physiology , Hand/physiologyABSTRACT
SUMMARY: During routine dissection of a left upper limb of a 68-year-old male human cadaver, an unusual muscle was observed originating from the radius and flexor retinaculum, and continued in the hypothenar region with the muscle belly of the abductor digiti minimi. We checked that it was an accessory abductor digiti minimi (ADM). Its muscular belly was in close relation to the median and ulnar nerves. We review the literature regarding such muscle variations and discuss the potential for compression of the median and ulnar nerves. Although the accessory ADM is usually asymptomatic and only rarely results in nerve compression, it should be taken into account by surgeons when establishing a differential diagnosis in the compression neuropathies of the median and ulnar nerves. An ultrasound scanning can help establish the differential diagnosis.
RESUMEN: Durante la disección de rutina de un miembro superior izquierdo de un cadáver humano masculino de 68 años, se observó un músculo inusual que se originaba en el radio y el retináculo flexor del carpo, y continuuaba en la región hipotenar con el vientre muscular del abductor digiti minimi manus. Verificamos que se trataba del músculo abductor digiti minimi accessorius (ADMA). Su vientre muscular se encontraba en estrecha relación con los nervios mediano y ulnar. Revisamos la literatura sobre variaciones musculares y discutimos la potencial compresión de los nervios mediano y ulnar. Aunque el ADMA suele ser asintomático y rara vez produce compresión nerviosa, los cirujanos deben tenerlo en cuenta al establecer un diagnóstico diferencial en las neuropatías de compresión de los nervios mediano y ulnar. Una ecografía puede ayudar a establecer el diagnóstico diferencial.
Subject(s)
Humans , Male , Aged , Muscle, Skeletal/abnormalities , Nerve Compression Syndromes/etiology , Ulnar Nerve , Cadaver , Risk Factors , Ulnar Nerve Compression Syndromes/etiology , Median Neuropathy/etiology , Median NerveABSTRACT
OBJECTIVE: The main aim of the present study is to examine the electrode configurations used to record the muscle motor evoked potential (mMEP) in the upper extremities during surgery with the goal of producing a high and stable mMEP signal, in particular among the abductor pollicis brevis (APB), abductor digiti minimi (ADM), and across the APB-ADM muscles, which have been widely used for the mMEP in the upper extremities. METHODS: Thirty right-handed patients were recruited in this prospective study. No patients showed any adverse events in their mMEP signals of the upper extremities during surgery. The mMEPs were recorded independently from the signals for the APB and ADM and for those across the APB-ADM. RESULTS: The mMEP amplitude from across the APB-ADM was statistically higher than those recorded from the APB and ADM muscles. Moreover, the coefficient of variation of the mMEP amplitude from across the APB-ADM was smaller than those of mMEP amplitude recorded from the APB and ADM muscles. CONCLUSION: The mMEP from across the APB-ADM muscles showed a high yield with high stability compared to those in each case from the APB and ADM muscles. The configuration across the APB-ADM muscles would be best for mMEP recordings from the upper extremities for intraoperative neurophysiological monitoring purposes.
Subject(s)
Humans , Electrodes , Evoked Potentials, Motor , Intraoperative Neurophysiological Monitoring , Muscles , Prospective Studies , Upper ExtremityABSTRACT
Soft tissue tumors of the foot have a low incidence rate, and most of them are symptom free, thus it is difficult to diagnose accurately. Herein, we report a 15-year-old male patient who had swelling without pain on the lateral margin of both feet. We performed excisional biopsy of the abductor digiti minimi via subtotal resection, following radiograph and magnetic resonance imaging. According to the histological analysis, hypertrophy of abductor digiti minimi was positive, and other soft tissue tumors were negative. Six months after the operation, normal appearance of both feet was maintained and the patient was satisfied with the result.
Subject(s)
Adolescent , Humans , Male , Biopsy , Foot , Hypertrophy , Incidence , Magnetic Resonance ImagingABSTRACT
Accessory muscles passing through Guyon's canal are common; the most common anomalous muscle at Guyon's canal is the accessory abductor digiti minimi muscle (AADM). The aim of this study was to demonstrate and describe the gross anatomy of an anatomic variant of the AADM relative to the surrounding structures. The AADM was found in the left forearm and hand of a 61-year-old male cadaver during dissection in a gross anatomy course. It was observed by focusing on the shape, the course, and its relationship with the surrounding structures. The AADM originated as muscle fibers from the antebrachial fascia. It coursed downward in the distal forearm and crossed the ulnar nerve and artery obliquely at Guyon's canal. The AADM narrowed and became a long tendon in the hypothenar region. The abductor digiti minimi muscle was partly attached to the tendon of the AADM, running along the tendon. The tendon of the AADM inserted into the ulnar side of head of the fifth metacarpal bone. The AADM was innervated by several twigs from the ulnar nerve. We reported herein another variant of the AADM at Guyon's canal, which may be helpful to surgeons performing diagnoses and surgical procedures.
Subject(s)
Humans , Male , Middle Aged , Anatomic Variation , Arteries , Cadaver , Fascia , Forearm , Hand , Head , Muscles , Running , Tendons , Ulnar NerveABSTRACT
PURPOSE: There are several methods to reconstruct the soft tissue defect of ankle area, including skin graft, local flaps, distant flaps and free flaps. Among them, the abductor digiti minimi (ADM) muscle flap is very useful for local flap coverage and we report a case using this unique and available technique. MATERIALS AND METHODS: A 31-year-old man with lateral malleolar soft tissue defect was referred from orthopedic surgery department. On physical examination, the wound has chronic osteomyelitis with bony destruction and discharge. After wound debridement, we detached the ADM from the head of the 5th metatarsal bone and transposed to the defected area. We placed the meshed split-thickness skin graft over the muscle flap and immobilized it using a tie-over dressing. RESULTS: He had an uneventful postoperative course without infection, dehiscence and flap necrosis. He has remained asymptomatic for 8 months without any recurrence such as osteomyelitis. In addition, he kept a normal gait and posture with weight bearing on the lateral border of the foot. CONCLUSIONS: We introduce very easy and useful ADM local transfer method and it is definitely indicative in the case of small, linear soft tissue defect.
Subject(s)
Adult , Animals , Humans , Ankle , Bandages , Debridement , Free Tissue Flaps , Gait , Head , Metatarsal Bones , Muscles , Necrosis , Orthopedics , Osteomyelitis , Physical Examination , Posture , Recurrence , Skin , Transplants , Weight-BearingABSTRACT
The supernumerary fascicles of abductor digiti minimi muscle have been implicated in vascular and nerve compression. During routine dissection of an old male cadaver we observed an anomalous muscle was found to take it's origin from the antebrachial fascia and flexor retinaculum, traversed ulnar canal (Guyon's) superficial to ulnar vessels and nerves to reach the proximal part of abductor digiti minimi. The anomaly is one of a kind. Its course through Guyon's canal could be a cause for Guyon's canal syndrome. It was innervated by the ulnar nerve.
Los fascículos supernumerarios del músculo abductor del dedo mínimo han sido implicados en la compresión neurovascular. Durante una disección de rutina de un cadáver masculino adulto, se observó un músculo anómalo que se originaba en la fascia antebraquial y en el retináculo flexor, atravesaba el canal ulnar, superficial a los vasos y nervio ulnares para llegar a la parte proximal del músculo abductor del dedo mínimo. La anomalía es única en su tipo. Su curso a través del canal ulnar puede causar el síndrome del canal ulnar. El músculo estaba inervado por el nervio ulnar.
Subject(s)
Humans , Male , Middle Aged , Ulnar Nerve/anatomy & histology , Ulnar Artery/anatomy & histology , Muscle, Skeletal/abnormalities , Cadaver , Anatomic Variation , Nerve Compression SyndromesABSTRACT
The general treatment methods of chronic osteomyelitis of calcaneus with soft tissue defect was curettage of necrotic bone with antibiotics mixed bone cement insertion or cancellous bone grafting, and free or pedicled flap coverage. The muscle flap for soft tissue defect has many advantages including control of infection, but in cases of pedicled flap in calcaneus, there are some limitations because of functional loss of the donor site, limitation of pedicled length of donor muscle In these reason, free muscle flap was more preferred for pedicled muscle flap. But, in case of small sized defect which was located in center or lateral side of calcaneus, the abductor digiti minimi muscle flap can be one of the solutions. The abductor digiti minimi muscle flap has minimal functional loss of donor site and can be performed easily. There are some reports of the abductor digiti minimi muscle flap in other country, but in korea, this report is the first case report of the abductor digiti minimi muscle flap. We performed one case of abductor digiti minimi muscle flap as a treatment of chronic osteomyelitis of calcaneus and could obtain a good result.
Subject(s)
Humans , Anti-Bacterial Agents , Bone Transplantation , Calcaneus , Curettage , Korea , Osteomyelitis , Surgical Flaps , Tissue DonorsABSTRACT
The Abductor digiti minimi muscle, and the other hypotenar muscles, frequently presents anatomical variations. According to literature, this muscle can be composed by one, two or three muscular beams, as well as it can present accessory muscular beams. In dissecations of 40 formolized hands, we objectified to study the morphology and variations of the Abductor digiti minimi muscle. The muscle presented two muscular beams in 82,5 %, three beams in 15% and only 1 beam in 2,5 % of the cases. In none of cases accessory muscular beams were observed. When compared with literature, are observed statistics difference in some studied aspects. The results found in the research allow to affirm that the Abductor digiti minimi muscle is formed by two muscular beams in the biggest part of the cases. The division of the muscle in three muscular beams is common of being found.
Tanto el músculo abductor del dedo mínimo como los otros músculos hipotenares presentan frecuentemente variaciones. De acuerdo con la literatura, el músculo abductor del dedo mínimo puede estar compuesto por uno, dos o tres vientres musculares, como también puede presentar cabezas accesorias. Fueron disecadas 40 manos de cadáveres formolizados, para verificar la morfología del músculo abductor del dedo mínimo y sus variaciones. El músculo presentó dos cabezas musculares en el 82,5 %, tres cabezas en el 15% y solamente una cabeza en el 2,5 % de los casos. No se observaron cabezas musculares accesorias. Hubo diferencias estadísticas al comparar las observaciones registradas del músculo, con los datos de la literatura. Los resultados encontrados en esta investigación afirman que el músculo abductor del dedo mínimo de la mano está formado por dos cabezas musculares, en la mayoría de los casos. Es frecuente encontrar un músculo abductor del dedo mínimo compuesto por tres cabezas.