Anatomic variations and MRI of the intermalleolar ligament.
OBJECTIVE
The purpose of this study was to identify the intermalleolar ligament morphologically and to correlate its shape with MR images.


METHODS
Seventy-seven ankles were used in this study. After the intermalleolar ligament had been located in the posterior ankle space, its medial and lateral attaching sites were identified, and its length, width, and thickness were measured. MRI was performed on 26 ankles before they were dissected (20 specimens) or serially sectioned (six specimens). The serial sections were taken at a thickness of 2 mm in the sagittal and horizontal directions.


RESULTS
The intermalleolar ligament was observed in 81.8% of the specimens and was composed of more than two bundles of fibers in all cases. The medial arising sites of the ligament were diverse (e.g., from the medial malleolus to the floor of the fibrous tunnel of the flexor hallucis longus). The ligament narrowed laterally and attached with the posterior talofibular ligament to the medial fossa of the lateral malleolus. Their morphologic shapes were also diverse, depending on their medial arising sites, the number of the composing fiber bundles, and the degree of bundle compactness. The intermalleolar ligament appeared as a thick string or as more than two fine parallel stripes on coronal MR images and as a linear structure on axial images. On sagittal images, the ligament appeared as scattered dots in the medial part and as a thin flat or nodular structure in the lateral part.


CONCLUSIONS
The intermalleolar ligament seemed to be an almost invariably present anatomic entity with diverse morphologic features on MR images.
Department of Anatomy, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 440-746, Korea. changoh@med.skku.ac.kr
Chang-Seok
CS
Oh
Hyung-Sun
HS
Won
Mi-Sun
MS
Hur
In-Hyuk
IH
Chung
Sungjun
S
Kim
Jin-Suck
JS
Suh
Ki-Sun
KS
Sung
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000033:anatomy & histology*; D002102:Cadaver; D005260:Female; D006801:Humans; D008023:Ligaments, Articular / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged