Deltoid Ligament

The triangular deltoid ligament is located medially and is attached above to the medial malleolus and below to the tuberosity of the navicular, the sustentaculum tali of the calcaneus, and the medial tubercle of the talus. The deltoid ligament is so strong that trauma often causes fractures of its bony attachments rather than rupture of the ligament itself. 

Fig. 16.3a). The deep fibers of the deltoid ligament are covered by synovium, and insert on the medial surface of the talus (Fig. 16.3b). In fact, the superficial and deep layers of the deltoid ligament are a continuum of fibers and their separation is somewhat artificial. The main function of the deltoid ligament is to stabilize the medial aspect of the ankle joint. It also serves to hold the calcaneus and navicular against the talus and reinforces the action of the spring ligament on which the head of the talus rests. 

The spring (plantar calcaneonavicular) ligament is a triangular bundle that extends from the anterior margin of the sustentaculum tali to the undersurface of the navicular bone. It blends with the deltoid ligament and plays a major role in stabilizing the longitudinal arch of the foot. 

Isolated rupture of the deltoid ligament is rarely encountered without additional injuries to the... 

Fig. 16.55. Partial-thickness tear of the deltoid ligament. Coronal 12-5 MHz US image over the medial ankle reveals hypoechoic thickening of the cranial portion of the tibiocalca-neal ligament consistent with a partial tear. Note the discrepant size between the injured (arrows) and the intact (arrowheads) portion of the ligament. C, calcaneus...

Total flexion of the shoulder joint can also be divided into three phases. In the first phase (0 to 60 degrees), the muscles used are the anterior fibers of the deltoid, the coracobrachialis, and the clavicular fibers of the pectoralis major. Motion is limited by the tension of the coracohu-meral ligament and by the resistance offered by the teres minor, teres major, and infraspinatus muscles. 

The ankle articulation consists of the distal end of the tibia and the medial and lateral malleoli, which together form a concave surface, the crural arch, into which is fitted the body of the talus. These bones are connected by the joint capsule and by the deltoid, anterior and posterior talofibular, and calcaneofibular ligaments. The tibial malleolus extends approximately one-third of the way down the medial surface of the talus and is anterior to the lateral malleolus. The fibular malleolus extends down the entire lateral aspect of the talus. When viewed from above, the entire articulation is laterally angled, thus creating a toeing-out of 15 degrees (Fig. 95-1). 

---