3/1/2023 0 Comments Normal ankle xray![]() Occasionally, they will manifest clinically, presenting as mass lesions or causing compression syndromes such as tarsal tunnel syndrome, chronic pain or impingement. Īccessory muscles are also generally asymptomatic and discovered incidentally on imaging studies. With respect to accessory sesamoid bones, the os peroneum is the most frequently found. The most common accessory ossicles in the ankle and foot are the os trigonum, the accessory navicular (among the different three types, type II is the most common) and the os intermetatarseum, in this order. They functionally represent components of a gliding mechanism and are at least partially embedded in tendons, reducing friction and protecting the tendon structure. Sesamoid bones have a different anatomical nature. They are seen as subdivisions of existing bones or free elements in the vicinity of the normal bone structures. Īccessory ossicles in most cases are a result of unfused ossification centres. Most of them represent developmental abnormalities that constitute incidental radiographic findings. These include accessory ossicles, additional sesamoid bones, variations in number and configuration of sesamoid bones, coalitions, bipartitions and variants in the soft tissues, such as accessory muscles. Calcaneofibular - spans between the lateral malleolus and the calcaneus.A number of anatomical variations can be found in the ankle and hindfoot.Posterior talofibular - spans between the lateral malleolus and the posterior aspect of the talus.Anterior talofibular - spans between the lateral malleolus and lateral aspect of the talus.It resists over-inversion of the foot, and is comprised of three distinct and separate ligaments: The lateral ligament originates from the lateral malleolus (a bony prominence projecting from the lateral aspect of the distal fibula). The primary action of the medial ligament is to resist over-eversion of the foot. It consists of four ligaments, which fan out from the malleolus, attaching to the talus, calcaneus and navicular bones. The medial ligament (or deltoid ligament) is attached to the medial malleolus (a bony prominence projecting from the medial aspect of the distal tibia). There are two main sets of ligaments, which originate from each malleolus. It is broad anteriorly, which strengthens the joint during dorsiflexion. Innervation is provided by tibial, superficial fibular and deep fibular nerves. The arterial supply to the ankle joint is derived from the malleolar branches of the anterior tibial, posterior tibial and fibular arteries. Dorsiflexion – produced by the muscles in the anterior compartment of the leg (tibialis anterior, extensor hallucis longus and extensor digitorum longus).Plantarflexion – produced by the muscles in the posterior compartment of the leg (gastrocnemius, soleus, plantaris and posterior tibialis).Eversion and inversion are produced at the other joints of the foot, such as the subtalar joint. Thus, plantarflexion and dorsiflexion are the main movements that occur at the ankle joint. The ankle joint is a hinge type joint, with movement permitted in one plane. For example, a fracture of the ankle joint may occur in association with ligament damage (which would not be apparent on x-ray). When dealing with an injury to the ankle joint, a clinician must bear this in mind. The sides of the ring are formed by the medial and lateral ligaments.Ī ring, when broken, usually breaks in two places (the best way of illustrating this is with a polo mint – it is very difficult to break one side without breaking the other).The lower part of the ring is formed by the subtalar joint (between the talus and the calcaneus).The upper part of the ring is formed by the articular surfaces of the tibia and fibula.The ankle joint and associated ligaments can be visualised as a ring in the coronal plane:
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