Supernumerary muscles in the posterior leg compartment: a case report / Músculos supernumerarios en el compartimento posterior de la pierna: reporte de un caso

SUMMARY: The leg muscles are organized in anterior, lateral and posterior compartments. The posterior compartment is usually divided in two layers: superficial and deep. The deep muscles of the posterior compartment of the leg are known to mainly plantar flexion and toes flexion. In comparison to the other leg compartments, variations of the posterior one are rare. These variants often involve the presence or absence of one or more muscles, and they have differences among origin and insertion, which leads to confusion between anatomists. We aim to describe a case of a male cadaver that possessed three supernumerary muscles in the lateral and posterior compartments of both legs: the peroneus quartus muscle and two accessory bellies of the flexor digitorum longus. This presentation seems to be very rare and scarcely reported in the literature. These variants have the potential of causing nervous or vascular compression, thus leading to tarsal tunnel syndrome or a symptomatic peroneus quartus. The clinical and surgical implications of this abnormal presentation is discussed.

RESUMEN: Los músculos de la pierna están organizados en compartimentos anterior, lateral y posterior. El compartimento posterior por lo general es dividido en dos capas: superficial y profunda. Se sabe que los músculos profundos del compartimento posterior de la pierna se caracterizan principalmente por participar de la flexión plantar y la flexión de los dedos de los pies. En comparación con los otros compartimentos de la pierna, las variaciones musculares en el compartimiento posterior son raras. Estas variantes suelen implicar la presencia o ausencia de uno o más músculos y presentan diferencias en el origen y en la inserción, lo que conduce a confusión entre los anatomistas. Nuestro objetivo fue describir el caso de un cadáver masculino que poseía tres músculos supernumerarios en los compartimentos lateral y posterior de ambas piernas: el músculo fibular cuarto y dos vientres accesorios del músculo flexor largo de los dedos. Esta presentación parece ser muy rara y escasamente reportada en la literatura. Estas variantes musculares tienen el potencial de causar compresión nerviosa o vascular, lo que conduce al síndrome del túnel del tarso o un cuarto músculo fibular sintomático. Se discuten las implicaciones clínicas y quirúrgicas de esta presentación anormal.

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.

Stenosing Peroneus Brevis Tendinitis Caused by Peroneus Quartus Tendon / 대한정형외과학회잡지

Peroneus quartus tendon is one of a group of accessory peroneal tendons present in humans. Associated pathologies include an attritional tear in the peroneus tendon, stenosing tendinitis, and peroneal tendon subluxation or dislocation. A 22-year old female patient, who presented suffering with lateral ankle pain and instability after ankle sprain, visited this hospital. The physical examination and MRI indicated a longitudinal tear of peroneus brevis tendon or chronic stenosing tendinitis caused by peroneus quartus tendon. Tenosynovectomy and an excision of the peroneus quartus tendon were performed. Satisfactory results were obtained at the 1 year follow-up after surgery. Orthopedic surgeons should consider the possible presence of the peroneus quartus tendon in a differential diagnosis of chronic lateral ankle pain.