Anatomic Variations and Magnetic Resonance Imaging of the Lateral Ankle Ligaments

Chung, In Hyuk; Lee, Hye Yeon; Suh, Jin Suck; Lee, Woo Hyeong; Jahng, Jun Seop

Abstract

The lateral ankle ligaments consisted of the anterior talofibular, posterior talofibular and calcaneofibular ligaments. This study was to investigate the dimensions and anatomic variations of these ligaments and correlate with MR images. Sixty seven ankles of Korean adults were used. Among these 37 ankles were only disseted and 30 ankles were dissected after getting MR images. The anterior talofibular ligament consisted of two bands in 72.4%. The length and thickness of this ligament were 20.9mm and 1.8mm, respectively. The widths were 7.0 mm in the upper band and 4.7 mm in the lower band. The talofibular ligament appeared as a hypointense thick band or several lines in MR images. This ligament was observed in 100% of the axial MR sections and 82.8% of the coronal sections. The posterior talofibular ligament showed single thick band in 53.2% while others showed as two bands. The length, width, thickness and the angle between the horizontal plane and the posterior talofibular ligament were 21.8 mm, 7.3 mm, 3.4 mm and 22.6degrees, respectively. In coronal MR images this ligament appeared as a hypointense and heterogeneous thick band between the lateral malleolus and the talus. All anterior and posterior talofibular ligaments were observed in axial MR images with at least one same MR plane showing the two ligaments together. The length, width and thickness of the calcaneofibular ligament were 25.3 mm, 5.2 mm and 2.3 mm, respectively. It was composed of two bands in 8.5%. The angles to the coronal and sagittal planes and this ligament were 20.7degrees(range 5degrees~60degrees) and 27.0degrees(range 7degrees~50degrees), respectively. The calcaneofibular ligament was seen as a hypointense short line or dot depending on the cut plane. It was observed in 72.4% of the axial MR images and in 75.9% of the coronal images but was better imaged in the coronal planes.