MR imaging of flexor digitorum accessorius longus.
OBJECTIVE
The flexor digitorum accessorius longus muscle (FDAL), an anomalous muscle about the ankle, has recently been implicated in tarsal tunnel syndrome. The purpose of this study is to document the prevalence of the FDAL, its MR appearance and its relation to the neurovascular bundle in the tarsal tunnel.


METHODS
The prevalence of the FDAL was determined from 100 ankle MR examinations in asymptomatic individuals. The appearance of the FDAL was summarized from 20 examples of FDAL: six gathered from the asymptomatic group and 14 acquired from a group of randomly collected cases of patients with ankle complaints.


RESULTS
The prevalence of the FDAL was 6%, calculated from the group of 100 asymptomatic individuals. Possessing a dominant fleshy component in the tarsal tunnel, the FDAL accompanies the posterior neurovascular bundle as it descends the ankle.


CONCLUSIONS
The FDAL is encountered in 6% of asymptomatic individuals. Its prominent fleshy component in the tarsal tunnel and its close proximity to the posterior tibial neurovascular bundle readily differentiate the FDAL from other medial anomalous muscles on MR imaging.
Cheung
Y Y
YY
Radiology Department, St. Vincent's Hospital, New York, NY 10011, USA.
Rosenberg
Z S
ZS
Colon
E
E
Jahss
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000842:Ankle / Q000002:abnormalities*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000002:abnormalities*; D009139:Musculoskeletal Abnormalities / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D013641:Tarsal Tunnel Syndrome / Q000175:diagnosis / Q000209:etiology; D013710:Tendons / Q000002:abnormalities