The ankle joint is a key joint between the lower leg and the foot and plays an important role in movement and stability. The foot bears the entire body’s weight every day and is therefore subject to significant stress. The upper ankle joint and the lower ankle joint work together to enable movements such as walking or running. In anatomy, bones such as the talus, calcaneus, and navicular bone are distinguished. Ligaments and muscles stabilize the ankle joint and protect it from injury. Stress on the joint often leads to conditions or ligament injuries. Ankle injuries are particularly common in sports. The interaction between the foot and the ankle is crucial for overall posture.
The Foot: Structure and Function
The foot (pes), the lower part of the leg, bears the entire body’s weight when standing upright and walking. The top of the foot is called the dorsum pedis, and the bottom is called the planta pedis. Foot movements are made possible by muscles—the short muscles of the foot and the long muscles of the lower leg. Muscles and ligaments are also responsible for maintaining the arch of the foot. The arch of the foot (longitudinal and transverse arches) is designed to cushion body weight.
The Three Sections of the Foot
The foot can be divided into three sections:
The tarsus, consisting of 7 tarsal bones (ossa tarsi):
The tarsus is located between the lower leg and the midfoot. Its seven bones are: the talus, the calcaneus, the navicular bone (os naviculare), the cuboid bone (os cuboideum), and the three cuneiform bones (ossa cuneiformia). The calcaneus is the largest tarsal bone and the attachment site for the Achilles tendon, the thickest and strongest tendon in the human body.
The forefoot (metatarsus) consists of five metatarsal bones (ossa metatarsalia):
The metatarsal bones are long bones and are connected to the toes at their anterior ends via joints. They can be divided into the base, shaft, and head.
The five toes (digiti pedis) with the toe bones (ossa digitorum pedis):
The big toe (hallux) consists of two phalanges; the remaining toes consist of three. Although the toes largely lose their grasping function in adults, this function can be regained through training. The two ankle bones (malleoli) are formed by bony projections of the tibia and fibula.
The Ankle Joint
The tarsal bone known as the talus forms the upper ankle joint (OSG, Articulatio talocruralis) together with the tibia and fibula of the lower leg. The lower ankle joint (USG) is formed by the talus, calcaneus, and navicular bone. Pain often occurs in the ligaments surrounding the capsule of the upper ankle joint due to strains or tears.
Diseases and Injuries of the Foot and Ankle
In addition to ligament strains and tears—which can be difficult to distinguish from one another—the ankle joint is also susceptible to fractures (ankle fracture, ankle dislocation fracture). Ankle fractures are the most common type of fracture in the lower extremity.
Malalignments or deformities can affect the entire foot or only individual parts of it. Congenital or acquired foot deformities include heel foot (pes calcaneus), high arch foot (pes cavus), clubfoot (pes equinovarus adductus et excavatus), flatfoot (pes valgus), flatfoot (pes planus), adductus foot (pes adductus), equinus foot (pes equinus, clubfoot), and splayfoot (pes transversoplanus).
Furthermore, conditions affecting the foot and ankle include, for example, heel spurs (excessive bone growth on the heel bone, which can cause severe pain), Achilles tendon tears (Achilles tendon rupture), and osteoarthritis.
FAQ
What is the ankle joint, and what is its function?
The ankle joint is the joint between the lower leg and the foot that allows for movements such as flexion and extension. It consists of the upper ankle joint and the lower ankle joint and is stabilized by ligaments.
Which bones make up the foot and ankle?
The ankle joint includes the talus, tibia, and fibula, as well as the calcaneus and other foot bones such as the navicular bone. Together, these form the articular surfaces and provide stability.
What is the difference between the upper and lower ankle joints?
The upper ankle joint primarily allows for upward and downward movement, while the lower ankle joint is responsible for rotational movements such as supination and pronation. Both joints work together functionally.
What conditions commonly affect the ankle joint?
Common conditions include osteoarthritis, ligament injuries, and foot deformities such as hallux valgus. Sports injuries involving the lateral malleolus are also common.
How is an ankle injury treated?
Depending on the severity, ankle injuries are treated conservatively or surgically. Physical therapy, stabilization through ligaments, and the ligamentous apparatus play an important role in this process.