The anterior inferior tibiofibular ligament (AITFL) is part of the lateral collateral ligament complex of the ankle.
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Gross anatomy
It generally has a trapezoidal shape, with multiple bands of fibers that extend obliquely in a distal and lateral direction from the tibia to the fibula 1. It usually becomes thicker from superior to inferior.
It starts from the distal tibia around 5 mm above the articular surface at the Chaput tubercle and descends obliquely between the adjacent margins of the tibia and fibula, anterior to the syndesmosis to the anterior aspect of the lateral malleolus at the Wagstaffe-Le Fort tubercle. Length ranges from 12-20 mm and thickness 1-3 mm.
Width range 3:
7-12 mm at the fibular insertion to
9-22 mm at the tibial insertion
Classification
One classification method according to Ray and Kriz is as follows 3:
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type 1: multiple fascicles (more than three) with or without small gaps between adjacent fascicles
type 1a: inferior fascicle separated from the rest of the ligament by a gap and possesses its own distinct proximal and distal attachments
type 1b: inferior fascicle is not completely separated from the rest of the ligament by a gap; either its proximal or distal attachment is continuous with the rest of the ligament
type 1c: multiple fascicles without gaps intervening between them
type 2: three fascicles or less; distinct inferior fascicle with both its proximal and distal attachments separate from rest of the ligament; inferior fascicle separated from the main portion of the ligament by a gap
type 3: three fascicles or less; distinct inferior fascicle with either its proximal or its distal attachment continuous with the rest of the ligament; gap does not completely separate the inferior fascicle from the rest of the ligament
type 4: three fascicles or less; the lower portion of the ligament possesses an inferior fascicle with both its proximal and distal attachments for the rest of the ligament
type 5: three fascicles or less; ligament with no separations or gaps within its structure and may or may not possess a fascicular arrangement