The calcaneofibular ligament groove at the inferior fibula, an ultrasonographic anatomical landmark

Abstract

PurposeCalcaneo bular bular ligament (CFL) injuries are harder to diagnose than anterior talo bular ligament (ATFL) ones. This study aimed to clarify the bular attachment of the CFL and verify the bony landmark for evaluating the CFL on ultrasonography. MethodsTo con rm the control function of the CFL, we performed passive movement manually using cadaveric ankles and observed the ankle positions where the CFLs were tense. The ATFL and CFL were removed, and the bone morphology of the CFL attachment and inferior bular end was imaged using a stereomicroscope and a 3D scanner. Using ultrasonography, we evaluated the bone morphology of the bular attachment of the CFL in short-axis images of healthy adult ankles. ResultsThe CFL was tensed according to ankle motions: supination, maximum dorsi exion, maximum plantar exion, and mild plantar exion-external rotation. Below the CFL attachment of the bula was a slight groove between the inferior tip and the obscure tubercle of the bula. This groove was observed in 81.5% of cases using short-axis ultrasonography. ConclusionThe CFL was tensed in various ankle positions to control the movements of the talocrural and subtalar joints. There was a slight groove at the inferior end of the bula where the CFL coursed downward. We called it the CFL groove and proposed that it could serve as a landmark for the short-axis image of ultrasonography.