An accessory abductor digiti minimi as possible risk factor of the median and ulnar nerves compression / Músculo abductor digiti minimi accesorio como posible factor de riesgo de la compresión de los nervios mediano y ulnar

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.

Resonancia magnética en el atrapamiento del nervio supraescapular por quiste supraglenoideo / Magnetic resonance in nerve entrapment suprascapular supraglenoid cyst

El síndrome de atrapamiento del nervio supraescapular es una causa infrecuente de dolor en el hombro y de difícil diagnóstico clínico. Puede ser consecuencia de traumatismo, infección, compresión extrínseca o estiramiento secundario a movimientos repetitivos. Los quistes supraglenoideos deben considerarse en el diagnóstico diferencial pues son una causa frecuente de compresión del nervio supraescapular que ocurre casi exclusivamente en hombres. Se evaluaron con resonancia magnética (RM) y en forma retrospectiva siete pacientes con diagnóstico de atrapamiento del nervio supraescapular por quiste supraglenoideo. La RM mostró la causa y localización de la compresión nerviosa así como la distribución del edema muscular en todos los casos. Puede evaluar el grado de severidad de la enfermedad y realizar el diagnóstico diferencial con otras causas que provocarían atrapamiento del nervio supraescapular. (AU)

Suprascapular nerve entrapment has been regarded as a relatively uncommon condition that is easily overlooked in the differential diagnosis of shoulder discomfort. The common feature is nerve damage, caused either by trauma, extrinsic compression or by stretching secondary to repeated movements. Ganglion cysts account for the majority of the masses causing entrapment and seem to occur exclusively in men. Seven cases of suprascapular nerve entrapment caused by supraglenoid cyst compression were reviewed with MRI. MRI showed the cause and location of nerve compression as well as the distribution of muscular edema in all cases. MR imaging also allows an evaluation of the severity of the disease. It is also very efficient in excluding several differential diagnoses. (AU)

Fracture of supracondylar process of the humerus

The supracondylar process of the humerus is a rare skeletal anomaly, which is usually an incidental finding while an X-ray is done for some other purpose. The process can fracture resulting in pain and tender mobile swelling over the medial aspect of the arm, and consequent neurovascular symptoms, or entrapment neuropathies. The anomaly, which fractured in a clinical situation, is described, followed by a review of the literature

effect of long-term use of computer mouse devices on median nerve entrapment

To assess the effect of long-term use of computer mouse devices on the median nerves. A cross-section prospective study conducted during the year 2004 involved 41 male secretaries employed in the Health Colleges of King Khalid University in Abha, Kingdom of Saudi Arabia. A questionnaire describing sociodemographic and computer use was completed. The electrophysiological study included measurements of motor latencies, motor conduction velocities, and amplitudes of compound muscle action potential of the right median nerve and compared these with those of the left median nerve [control]. All of our subjects were right handed. Terminal latency index [TLI] was calculated for each nerve tested. Entrapment neuropathy of the median nerve at the wrist was defined as TLI <0.30. The mean TLI of the median nerve in the right hand was significantly lower than that in the left hand. Eight of the 23 asymptomatic participants [34.8%], 6 of the 12 who reported hand discomfort [50%], and all the 6 participants who met clinical criteria for carpal tunnel syndrome showed electrophysiological evidence suggestive of right median nerve entrapment neuropathy at the wrist. Test of association showed a negative and significant correlation between TLI of the right median nerve and weekly hours mouse device use while no significant correlation was found between TLI in the same hand and weekly hours keyboard use. Frequent computer mouse device users are at high risk of developing median nerve entrapment neuropathy at the wrist

Median nerve palsy after operative treatment of olecranon fracture.

Olecranon fracture is not an uncommon fracture in clinical practice. Simple olecranon fracture usually heals quite well without any types of iatrogenic complications. Despite close proximity of the fracture to the nerve, median nerve palsy after operative treatment of olecranon fracture is a rare complication. To the authors' knowledge, this complication has not been previously reported in the Thai or English literature. The authors present a patient who had median nerve palsy after tension-band wiring for olecranon fixation. Intraoperative finding revealed that the median nerve was injured by the tip of K-wire. While this complication is uncommon on a per-person basis, it may results in serious complication, such as nerve palsy or limb ischemia. Orthopedic surgeons must remain vigilant with regard to any type of internal fixation in the upper extremity because the risk of neurovascular injury is high.

Reconstructive surgery in upper limbs in leprosy.

Of all the deformities in leprosy, 80% require minor surgery and the rest major surgery. Upper and lower limbs and face are mainly affected by deformities. Either the median or ulnar nerve and rarely the radial nerve are involved in isolation or in combination. Tendon transfer is the only option available in cases of deformities like simian hand, ulnar claw hand, wrist drop and failure to the metacarpals. The only motor function to be restored in median nerve palsy is opponensplasty. For radial nerve palsy standard FCU transfer, FDS transfer and FCR transfer are the reconstructive methods. For ulnar nerve palsy, an intrinsic minus hand function is restored by the motors PL, ECRL, FDS, EIP or EDM extended by four tail fascia lata graft onto lateral or ulnar bands of fingers. When ulnar nerve is part of much more extensive paralysis, reducing the availability of suitable motors, static mathods of conection of claw hand are done.

Median nerve palsy following claw finger correction in leprosy: effect of M. leprae or a consequence of surgery.

Median nerve palsy, though not a frequent occurrence after claw finger correction, does exist as a post-operative complication after claw finger correction. A retrospective study was carried out to examine the occurrence of post-operative median palsy, in cases of isolated ulnar palsy, where the transferred motor tendon was routed through the carpal tunnel. We noted that six patients developed median nerve palsy following claw finger correction. Median palsy developed at different times after surgery--the "early onset" type developing within three weeks post-operatively, "reactional" type developed when patient was undergoing physiotherapy exercises and learning to use the transfer and "delayed insidious" type presenting six months or more after operation. We could not succeed to get the true prevalence of such occurrences because all the operated hands could not be re-examined.