The ankle is the portion of the body where the foot and leg join together. Although the ankle is frequently referred to as one joint, it is, in fact, three different joints. The three joints that make up the ankle include the inferior tibiofibular joint, the subtalar joint, and the talocrural joint/proper ankle joint.
The bones in the ankle region belong to both the foot and leg. The bones of the leg that can be found in the ankle include the fibula and tibia. Meanwhile, the foot bone in the ankle region is the talus. Beyond the bones within the ankle, the ankle is connected to the foot and leg through a number of different ligaments and tendons. Let’s take a closer look at the anatomy of the foot and ankle, examining the bones and tendons that comprise it.
General Anatomy Of The Foot And Ankle
The ankle joint is made out of the foot and leg bones together. The talocrural joint, or ankle joint, is where the leg’s distal end joins together with the foot. The ankle joint is where the talus and tibia join together. The tibia is the shin and it links with the talus, the topmost part of the foot. The ankle functions as both a huge joint and a synovial joint. The talus bone slots into fibula and the lower portion of the tibia. There are two bony protrusions that envelop the talus and sit on either side of the ankle. The hinge joint designation comes from the fact that the concave part of one bone fits onto the convex part of the adjacent bone.
The smaller fibula and the large tibia are the two leg bones which meet at the ankle joint and create a stable, supportive joint. This type of joint is referred to as a mortise and tenon joint. The ankle joint lets the foot extend and flex, or move down and up. The joint of the ankle is the most stable when the foot is pointed downward, or extended, compared to when the toes are pointed upwards. The ankle joint allows other movements as well, such as the rotation and tilting of the foot.
A series of strong ligaments surround the bones. These ligaments are the posterior talofibular ligament, the calcaneofibular ligament, and the anterior talofibular ligament. These ligaments are surrounded by fibrous tissue referred to as the articular capsule, and underneath the ligaments is a thin stretch of tissue referred to as the synovial membrane. The ankle joint is supplied by various arteries, such as the anterior tibial and peroneal arteries. The ankle also has the tibial and peroneal nerves surrounding it.
The foot is found below the ankle, and it is the basis for the body’s posture and movement. The digits on the foot, the toes, aren’t as mobile as the fingers found on the hand. Perhaps the greatest difference between the digits of the hand of the digits of the foot is the difference between the metacarpal bone of the thumb and the metatarsal bone found in the big toe. The metatarsal bone found in the big toe gives the body support and balance. The big toe metatarsal is aligned with the other metatarsals. The tarsus forms much of the foot and without it, the posture of the body is difficult to maintain. The metatarsus and tarsus are made out of various arches in order to support the weight of the body’s muscle and skeleton.
Bones Of The Foot And Ankle
The bones of the foot and ankle include the phalanges, the metatarsals, and the tarsals. The calcaneus (heel) and the talus are the bones which make up the rear portion of the foot/hindfoot. The calcaneus meets the talus at the subtalar joint. The subtalar joint is what lets the food move from side-to-side.
The tarsal bones are seven different bones. The seven different tarsal bones are: the first, second, and third cuneiforms, the navicular, the talus, the cuboid, and the calcaneus. The foot and leg muscles rotate the foot in one direction and the tarsal bones, as a result, form a rigid structure together. As the foot moves in the opposite direction, the tarsal bones become flexible once more.
The calcaneus is the largest bone out of all the tarsals. The function of the calcaneus is to absorb the weight of the body and transmit it into the ground. The calcaneus also functions as a lever that works upon of the calf muscles. The calcaneus is linked with the cuboid and talus. The talus, or ankle bone, is found on top of the calcaneus and is is the second largest of all the tarsals. Together with the fibula, tibia, calcaneus, and navicular, the talus forms a joint.
The cuboid is found opposite the foot arch, on the lateral side of the foot. It is located in front of the calcaneus. The cuboid forms a joint by combining the fourth and fifth metatarsals, the third cuneiform, and the calcaneus. The navicular is found between the cuneiform bones and the talus, with the cuneiform bones in front of it and the talus located behind it. The navicular as found on the tarsus’ medial side. The navicular forms a joint with the assistance of four other bones. These bones are the three cuneiforms and the talus, though the joint sometimes includes the cuboid as well.
The cuneiform bones linked with various other bones to create three different joints. The first cuneiform joins together with the navicular, the first and second metatarsals, and the second cuneiform. The second cuneiform links with the second metatarsal, the navicular, and the first and third cuneiforms. The third cuneiform binds together with the second, third, and fourth metatarsals as well as the navicular, the second cuneiform, and the cuboid.
There are five bones that run from the arch to the opposite side of the foot, and these bones are collectively referred to as the metatarsus. Each of the tarsals are connected to five long bones referred to as the metatarsals. The tarsals and metatarsals are joined together by joints that don’t allow for much movement. One or more of the tarsal bones are connected via a joint with the metatarsal bones, while on the other hand the metatarsals are connected with the first row of the phalanges. The first metatarsal creates a joint by linking together with its respective cuneiform. Meanwhile, the second metatarsal is joined together with all three remaining uniforms. The third cuneiform is joined with the third metatarsal, and the fourth metatarsal is linked with the cuboid and the third cuneiform. Finally, the fifth metatarsal is joined together with the cuboid.
The bones found within the toes are called the phalanges, much like how the bones in the fingers of the hand are referred to as phalanges. The joints found between the first phalanx and the metatarsals are, naturally, called the metatarsal phalangeal joint. In conjunction, these joints make up the ball of the foot,
There are two phalanges in the big toe and three phalanges each in the other toes. In general, this arrangement corresponds to the phalanges found in hand. The size and shape of the phalanges differs in the foot, however. The size of the phalanges in the foot is shorter overall, but wider, especially in the first row of phalanges. Very little movement occurs at the joints between the phalanges. Out of all of the phalanges, those located in the big toe are the most important for maintaining balance while walking.
In all of the toes except the first toe, the phalanges located in the first-row bond together with metatarsal bones and create joints. They also form joints with the second phalanges, and these second-order joints form their own joints with the first and third phalanges.
Ligaments Of The Ankle And Foot
The ankle and foot have many soft tissues within them, such as tendons, ligaments, nerves and blood vessels, and fascia.
The ligaments found within the ankle and foot function to link bones to bones, and they are dense, strong, lengths of connective tissue which are quite flexible. In addition to attaching bones to bones, ligaments help stabilize joints. The ankle joint is wrapped up in three lateral ligaments and a deltoid ligament. The three ligaments found within the ankle are the calcaneofibular ligament, the posterior talofibular ligament, the anterior talofibular ligament.
In addition to ligaments, various tendons pass through the ankle region. Tendons join muscle to bone. The major tendons found within the foot and ankle include the Achilles tendon, the flexor hallicus longus, the flexor digitorum, the peroneal tendons, the posterior tibialis tendon, and the anterior tibialis tendon. The Achilles tendon attaches to the calcaneus and the calf muscle. The flexor hallicus longus is attached to the big toe and runs through the inside of the ankle. Similarly, the flexor digitorum is attached to the other toes and runs through the inside of the ankle.
The peroneal tendons are three different tendons that are found on the outside of the ankle and a run through the bottom of the foot to attach to the fifth metatarsal. The posterior tibialis tendon is located in the middle of the foot and it helps move and maintain the arch of the foot. Finally, the anterior tibialis tendon is responsible for pulling the foot towards the body, and it is attached to the bones found in the midfoot.