Spring complex ligament.

A) Anatomy:

Fig 1: A fat-suppressed proton-density weighted coronal image of the ankle demonstrates the normal appearance of the superomedial portion of the spring ligament (arrowheads), which is seen deep to the posterior tibial tendon (arrow). The inferior portion of the spring ligament complex, consisting of the inferoplantar and medioplantar oblique components, demonstrates greater heterogeneity of signal because of interposed fat between the ligament bundles (small arrows).

Fig 2: A more posterior fat-suppressed proton density-weighted coronal image demonstrates the tibiospring portion of the deltoid ligament complex (arrow) fusing with the superior margin of the superomedial spring ligament (arrowheads). The posterior tibial tendon (arrow) is clearly discernible as separate from the superomedial spring ligament at this level.

Fig 3: A T2-weighted axial image demonstrates the normal appearance of the superomedial portion of the spring ligament(arrowheads), which forms the medial wall of the talonavicular joint and is seen immediately deep to the posterior tibial tendon (arrow).

Finally look in the coronal image at the level of the medial malleolus for tibio-spring ligament as it is merges from (Fig 2) and follow it till it reaches medial to tibialis posterior tendon here its junction with super-medial portion of spring complex ligament then follow him below talus where it continue as inferior portion (fig 1). 


B) Pathology:

Sequential T2-weighted axial images demonstrate partial tears of the distal posterior tibial tendon (arrows). The SM-CNL is abnormally thickened without focal discontinuity (arrowheads).

Sequential T2-weighted axial images in a patient with a partial tear of the distal posterior tibial tendon (arrow), demonstrate an abnormally lax and thickened SM-CNL along its anterior fibers (arrowheads). The posterior fibers of the SM-CNL are torn near the sustentaculum (small arrows). Also noted is abnormal thickening of the anterior talofibular and calcaneofibular ligaments (short arrows) indicating scarring secondary to prior ligament sprains.

A T2-weighted axial image demonstrates a large tear of the SM-CNL (arrowheads) at the navicular, resulting in a large ligament gap (small arrows). Note that the posterior tibial tendon (arrow) contacts the medial head of the talus within the the ligament defect.

Reference