These articulations allow the foot to rotate smoothly around the talus. The talus connects to the calcaneus on the underside through the subtalar joint, and distally it connects to the navicular through the talonavicular joint. Because it articulates with so many other bones, 70% of the talus is covered with hyaline cartilage (joint cartilage). The talus is the top (most proximal) bone of the foot. The prominence on the medial side of the distal tibia is known as the medial malleolus the distal aspect of the fibula is known as the lateral malleolus. The tibia and fibula are held together by the tibiofibular syndesmosis, a collection of 5 ligaments. The fibula accepts the remaining 15% its main role is to serve as the lateral wall of the ankle mortise (Figure 4). In a typical foot the tibia is responsible for supporting about 85% of body weight. The foot is connected to the body where the talus articulates with the tibia and fibula. Joints of the hindfoot: Ankle (Tibiotalar), Subtalar. midfoot joint)īones of the lower leg and hindfoot: Tibia, Fibula, Talus, Calcaneus. Tarsometatarsal (TMT) joint “Lisfranc” Joint (a.k.a. Joints with Minimal Movement (Non-Essential Joints): Mobile Joints of the Foot and Ankle (Essential Joints):Ĭuboid-metatarsal joint for the fourth and fifth metatarsal. Rather the correct sense is only that movement from these joints is less critical. (This may be a poor term in that it incorrectly implies that the joints are not important they are important. These non-mobile joints are sometimes referred to as non-essential joints. There are some joints that move a moderate amount, and there are other joints that are held tightly together with strong ligaments. These are often referred to as essential joints. A few of the joints are quite mobile and are required for the foot to function normally from a biomechanical point of view. It is helpful to think of the joints of the foot based on their mobility (Table 1). Where two bones meet a joint is formed –often supported by strong ligaments. The foot is comprised of 28 bones (Figure 1). There are two sesamoid bones embedded in the flexor hallucis brevis tendons that sit under the first metatarsal at the level of the great toe joint (1st metatarsophalangeal joint). The great toe has only a proximal and distal phalanx, but the four lesser toes each have proximal, middle, and distal phalanges, which are much small than those of the great toe. There are twenty-one bones in the forefoot: five metatarsals, fourteen phalanges, and two sesamoids. The bones that make up the forefoot are those that are last to leave the ground during walking. The Forefoot is composed of the metatarsals, phalanges, and sesamoids. The five bones of the midfoot comprise the navicular, cuboid, and the three cuneiforms (medial, middle, and lateral). While the midfoot has several more joints than the hindfoot, these joints have limited mobility. The Midfoot begins at the transverse tarsal joint and ends where the metatarsals begin -at the tarsometatarsal (TMT) joint. The bones of the hindfoot are the talus and the calcaneus. The Hindfoot begins at the ankle joint and stops at the transverse tarsal joint (a combination of the talonavicular and calcaneal-cuboid joints). Additionally, the lower leg often refers to the area between the knee and the ankle and this area is critical to the functioning of the foot. The foot is traditionally divided into three regions: the hindfoot, the midfoot, and the forefoot (Figure 2). These will be reviewed in the sections of this chapter. There are a variety of anatomical structures that make up the anatomy of the foot and ankle (Figure 1) including bones, joints, ligaments, muscles, tendons, and nerves. With a good grasp of foot anatomy it readily becomes apparent which surgical approaches can be used to access various areas of the foot and ankle. For those conditions that require surgery a detailed understanding of anatomy is critical to ensure that the procedure is performed efficiently and without injuring any important structures. Therefore a basic understanding of surface anatomy allows the clinician to quickly establish the diagnosis or at least narrow the differential diagnosis. Anatomical structures (tendons, bones, joints, etc) tend to hurt exactly where they are injured or inflamed. Most structures in the foot are fairly superficial and can be easily palpated. A solid understanding of anatomy is essential to effectively diagnose and treat patients with foot and ankle problems.
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