Accessory Belly of the Piriformis Muscle as a Cause of Piriformis Syndrome: a Case Report with Magnetic Resonance Imaging and Magnetic Resonance Neurography Imaging Findings

Piriformis syndrome caused by an accessory belly of the piriformis muscle is very rare. Only a few cases have been reported. Here, we report a case of piriformis syndrome resulting from an extremely rare type of accessory belly of the piriformis muscle originated at the proximal third portion of the main piriformis muscle and attached separately to the greater trochanter inferior to the insertion of the main piriformis muscle. A definitive diagnosis of piriformis syndrome was made based on magnetic resonance imaging and magnetic resonance neurography findings that were consistent with results of nerve conduction study and needle electromyography.

You can never have too many accessories - a case of two accessory muscles of the ankle

Accessory muscles are relatively rare anatomic duplications of muscles that may appear anywhere in the muscular system. Though a wide array of accessory and supernumery muscles involving the ankle have been described in the literature, this is the first reported case we are aware of that features two accessory muscles. Accessory muscles are typically asymptomatic and often picked up as incidental findings but are important to be identified in the presence of chronic persistent ankle pain and the absence of other more common aetiologies.

The MRI Findings of Flexor Digitorum Accessorius Longus Muscle: a Case Report

The flexor digitorum accessorius longus (FDAL) is the most common accessory muscle found in the posterior compartment of the ankle area. The accessory muscle in this area such as the FDAL may be incidentally identified on magnetic resonance images (MRI). There are some case reports about the FDAL in cadaver researches. However, the MRI findings about the FDAL have been reported in a few cases. In this paper, we report a case of the FDAL incidentally identified on MRI with review of the literature about the FDAL.

Variations in the Muscles of the Extensor Compartment of The Forearm and Hand and Its Clinical Significance.

Background: The extensor musculature of the forearm and hand shows diverse variations. These can lead to various clinical conditions. Case Report: During routine cadaveric dissection, variations were observed in the muscles of extensor compartment of the forearm. Their anatomical relations were documented and the embryological basis and clinical importance was stressed upon. During routine cadaveric dissection in a formalin fixed 58 year old male cadaver, variations in the posterior compartment of the left forearmwere noted,measured and appropriately photographed. Observations: In the posterior compartment of the left forearm an accessorymusclewas found originating from the posterior surface of ulna, just distal to the origin of extensor indicis. It traversed along with the tendons of extensor digitorum and extensor indicis in a common compartment underneath the extensor retinaculum and inserted onto the dorsal surface of the base of the proximal phalanx lateral to the tendon of extensor digitorum for the middle finger. Also, the extensor digitorum muscle divided only into three tendons instead of four- one each for the index,middle and ring finger. The three tendons inserted normally via the dorsal digital expansion but, the tendon for the ring finger gave an additional slip on the ulnar aspect, which inserted separately onto the base of the proximal phalanx of the ring finger. Conclusion: Muscles in the extensor compartment of forearm may show diverse variations which have clinical relevance. Accessorymusclesmay be confused with soft tissue conditions like a ganglion. Supernumary tendons can be utilised for tendon transfers andmuscle grafts. These variationsmust be brought to the knowledge of the surgeons performing hand surgeries.

Accessory muscle in the forearm: a clinical and embryological approach / 대한해부학회지

Muscular variations of the flexor compartment of forearm are usual and can result in multiple clinical conditions limiting the functions of forearm and hand. The variations of the muscles, especially accessory muscles may simulate soft tissue tumors and can result in nerve compressions. During a routine dissection of the anterior region of the forearm and hand, an unusual muscle was observed on the left side of a 65-year-old male cadaver. The anomalous muscle belly arose from the medial epicondyle approxiamately 1 cm posterolateral to origin of normal flexor carpi ulnaris muscle (FCU), and from proximal part of the flexor digitorum superficialis muscle. It inserted to the triquetral, hamate bones and flexor retinaculum. Passive traction on the tendon of accessory muscle resulted in flexion of radiocarpal junction. The FCU which had one head, inserted to the pisiform bone hook of hamate and palmar aponeurosis. Its contiguous muscles displayed normal morphology. Knowledge of the existence of muscle anomalies as well as the location of compression is useful in determining the pathology and appropriate treatment for compressive neuropathies. In this study, a rare accessory muscle has been described.

Músculo accesorio del abductor largo del pulgar o tercer abductor / Accessory long abductor muscle of the thumb or third abductor

En el estudio de los tendones del músculo accesorio del abductor largo del pulgar, basados en la disección anatómica de 250 cadáveres adultos de raza mestiza del altiplano y valle, registramos que las variaciones anatómicas son muy frecuentes. La presencia de tendones accesorios ocurrió en todas las piezas disecadas. Este músculo constante, en nuestro medio se origina en el tercio inferior de la cara dorsal del radio, ulna y de la membrana interósea; diferenciandose del abductor largo del pulgar y del extensor corto del pulgar. Se dirige hacia abajo al nivel de la muñeca, pasa por debajo del retináculo extensor en la primera corredera osteofibrosa de la epífisis distal del radio junto con el abductor largo y extensor corto del dedo pulgar. Su inserción distal se realiza en primer metacarpiano.

In the study of the tendons of the accessory muscle of the long abductor of the thumb, based on the anatomical dissection of 250 mature cadavers of mestizo race of the highland and valley, we register that the anatomical variations are very frequent. The presence of accessory tendons happened in all the dissected pieces.This constant muscle, in our means, originates in the inferior third of the dorsal face of the radius, ulna and of the membrane interosseous; differing of the long abductor of the thumb and of the extending one short of the thumb. He she goes down, at the doll's level, it passes below the extending retináculo in the first sliding osteofibrosa of the lower extremity of the radius together with the short long and extending abductor of the thumb. Their insert distal is carried out in first metacarpal.