Ankle + Foot
BONES
The following bones make up the ankle and foot: Tibia, Fibula, 7 tarsal bones, 5 metatarsal bones and 14 phalanges. In total there are 28 bones that make up the ankle and foot (26 bones in the foot, and 2 bones in the lower leg). The tibia, fibula and talus (the superior tarsal bone), make up the main ankle joint. This joint is called the talocrural joint and within this main joint, there are specific joints.
Bones | Info about this bone | Picture |
| Tibia | The tibia (also known as the shin bone) is connected to the knee and the bones in the ankle, and it is located on the medial side of the leg. It is the stronger and larger bone in the leg, when compared to the fibula, the other bone in the leg which is lateral to the tibia. The tibiotarsal joint is a joint of the upper ankle, and is formed by the distal head of the tibia articulating with the talus. The main action of the ankle occurs at the tibiotarsal joint, and it is a synovial hinge joint. |  |
| Fibula | The fibula is located on the lateral side of the leg, below the knee and is lateral to the other bone in the leg, the tibia. It is the smaller bone located in the leg. The fibulotalur joint is formed by the fibula articulating with the talus. The lateral malleolus is located at the distal end of the fibula and is a bony protuberance. |  |
| Tarsals (7) | In the foot there are 7 tarsal bones which are the: Talus (important for the main ankle joint), Calcaneuous (heel bone), Navicular, Cuboid, and the 3 Cuneiforms (lateral, intermediate, medial). |  |
| Metatarsals | Just like in the hand, there are 5 metatarsal bones in the foot, which align with the phalanges. These metatarsal are numbered from 1 to 5. Metatarsal 1 is in line with the big toe and metatarsal 5 is in line with the pinky toe. |  |
| Phalanges | Each toe per foot consists of 3 phalanges, minus the big toe since it only has 2, so there are a total of 14 phalanges in each foot. Another name for the big toe is the hallux. |  |
LIGAMENTS
Since there are a numerous amount of bones and joints present in the foot, there are also a large number of ligaments that are present. There are a total of 31 joints. The following ligaments are found in the ankle and foot:
Ankle Ligaments - Medial Collateral Ligaments: The medial malleolus is attached to the talus and navicular bones, via the medial collateral ligament (deltoid ligament). It is composed of the following 4 ligaments:
- Anterior tibiotalar ligament
- Posterior tibiotalar ligament
- Tibionavicular ligament
- Tibiocalcaneal ligament
Ankle Ligaments - Lateral Collateral Ligaments: The lateral malleolus is attached to the talus via the lateral collateral ligament. It is composed of the following 3 ligaments:
- Anterior Talofibular Ligament
- Posterior Talofibular Ligament
- Calcaneofibular Ligament
Ligaments In The Foot:
- Intertarsal Ligaments: Attach the tarsals to one another.
- Tarsometatarsal Ligaments: Attach the tarsals to the metatarsals.
- Metatarsophalangeal Ligaments: Attach the metatarsals to the phalanges (this is a collateral ligament).
- Interphalangeal Ligaments: Attach the phalanges to one another (this is a collateral ligament).
BONE MARKINGS
- Medial Malleolus: In the ankle joint, the medial malleolus acts as a stabilizer and it is a bony protuberance on the inner side of the ankle. It is located at the inferior aspect of the tibia bone.
- Lateral Malleolus: In the ankle joint, the lateral malleolus also acts as a stabilizer and it is a bony protuberance on the outer side of the ankle. It is located at the inferior aspect of the fibula bone, and the lateral malleolus sits more inferior than the medial malleolus.
MUSCLES
Anterior muscles of the lower leg:
Info about this muscle | Picture | |
| Extensor Digitorum Longus | The Extensor Digitorum Longus is located behind the tibialis anterior, and along the outside of the lower leg. This muscle assists in ankle dorsiflexion and extends digits 2-5 in the foot. |  |
| Extensor Hallucis Longus | The Extensor Hallucis Longus is a thin muscle that is located between the Tibialis anterior and the Extensor digitorum longus. This muscle extends the big toe and dorsiflexes the ankle. |  |
| Tibialis Anterior | The Tibialis Anterior is located just behind the big toe. This muscle helps with ankle dorsiflexion and forefoot inversion at the subtalar joint. |  |
Lateral muscles of the lower leg:
| Info about this muscle | Picture | |
| Peroneus Brevis | The Peroneus Brevis is located underneath the Peroneus Longus muscle, and it extends along the outer portion of the lower leg and foot. This muscle assists the foot with plantar flexion and eversion. |  |
| Peroneus Longus | The Peroneus Longus is located within the lateral compartment of the lower leg, and it also extends along the outer portion of the lower leg and foot. This muscle assists the foot with plantar flexion and eversion. |  |
Posterior muscles of the lower leg:
Info about this muscle | Picture | |
| Tibialis Posterior | The Tibialis Posterior is a deep muscle of the lower leg and is located within the back side of the calf. This muscle assists the foot with plantar flexion and also inversion of the foot. |  |
| Soleus | The Soleus is located beneath the gastrocnemius and is a part of the superficial posterior compartment. This muscle assists the foot with plantar flexion. |  |
| Gastrocnemius | The Gastrocnemius is located on the back portion of the lower leg, which is one of the muscles that make up the calf. This muscle assists in knee flexion and ankle plantar flexion. |  |
| Flexor Digitorum Longus | The Flexor Digitorum Longus is a deep muscle of the lower leg and is located on the tibial side of the leg. This muscle is in charge of flexing digits 2-5 in the foot, and assists the foot with plantarflexion, inversion and adduction of the foot. |  |
| Flexor Hallucis Longus | The Flexor Hallucis Longus is a deep muscle of the lower leg and is located on the inner side of the leg by the tibia. This muscle functions to flex the big toe, and it assists in inversion and plantarflexion of the foot. |  |
TENDONS
Achilles Tendon: The Achilles Tendon attaches the gastrocnemius and soleus to the calcaneus, and it is the largest and strongest tendon in the body. However it is more susceptible to injury since there is a high level of tension placed on it.
ORIGINS AND INSERTIONS
Anterior Compartment:
| Muscle | Origin & Insertion Points |
| Extensor Digitorum Longus | The Extensor Digitorum Longus originates on the anterior fibula and inserts on the intermediate and distal phalanges. |
| Extensor Hallucis Longus | The Extensor Hallucis Longus originates on the anterior fibula and inserts on the distal phalanx of the hallux (big toe). |
| Tibialis Anterior | The Tibialis Anterior originates on the lateral tibia and inserts on the medial cuneiform and 1st metatarsal. |
Posterior Compartment:
| Muscle | Origin & Insertion Points |
| Flexor Digitorum Longus | The Flexor Digitorum Longus originates on the posterior fibula and inserts on the distal phalanx of digits 2-5. |
| Flexor Hallucis Longus | The Flexor Hallucis Longus originates on the posterior fibula and inserts on the distal phalanx of the hallux. |
| Tibialis Posterior | The Tibialis Anterior originates on the posterior tibia and inserts on the tarsals. |
| Soleus | The Soleus originates on the posterior tibia and posterior fibula, and it inserts on the calcaneus. |
| Gastrocnemius | The Gastrocnemius originates on the posterior femur and inserts on the calcaneus. |
Lateral Compartment:
| Muscle | Origin & Insertion Points |
| Peroneus Longus | The Peroneus Longus originates on the lateral fibula and inserts on the medial cuneiform and 1st metatarsal. |
| Peroneus Brevis | The Peroneus Brevis originates on the lateral fibula and inserts on the 5th metacarpal. |
JOINTS
Joints of the ankle - The following joints play a crucial role in the stability and mobility of the ankle.
- Inferior Tibiofibular Joint: This is a fibrous joint (synarthrotic) and the only fibrous joint which can be found in the appendicular skeleton. The inferior tibiofibular joint also lays the foundation for the ankle joint. There are no movements that this joint may perform.
- Talocrural Joint: This is a synovial hinge joint (diarthrotic) and is where the superior aspect of the talus bone articulates with the inferior aspects of the tibia and fibula. The talocrural joint is the main ankle joint. Two movements that this joint may perform are dorsiflexion and plantarflexion.
- Subtalar Joint (Talocalcaneal Joint): This is a synovial plane joint and is an articulation between the talus and calcaneus. Two movements that this joint may perform are inversion (when the sole of the foot faces in) and eversion (when the sole of the foot faces out).
Joints of the foot - In this area, we are mainly going to focus on groups of joints.
- Talocalcaneonavicular Joint: This is a synovial ball-and-socket joint and is found between the talus, calcaneus and navicular tarsal bones, since it is an intertarsal joint. Two movements that this joint assists with are inversion and eversion.
- Intertarsal Joints: This is a synovial plane joint and these joints are located between the tarsal bones. Each joint has an individual name but as a group are known as intertarsal joints A movement that this joint can perform is slight gliding.
- Tarsometatarsal Joints: This is a synovial plane joint and this joint is formed between the distal surface of the cuboid bone and the 3 cuneiform bones, with the metatarsals. A movement that this joint can perform is slight gliding.
- Metatarsophalangeal Joint (MTP Joints): This is a synovial condyloid joint, so the concave base of the phalanges articulate with the convex head of the metatarsal. Metatarsophalangeal joints are formed by the metatarsals articulating with the phalanges. Four movements that this joint may perform are flexion and extension, and a slight amount of adduction and abduction.
- Interphalangeal Joints: This is a synovial hinge joint and these joints are located between the phalanges, in the toes. There are proximal interphalangeal joints (PIP) and distal interphalangeal joints (DIP) which are both types of interphalangeal joints. Two movements that this joint can perform are flexion and extension.
MOVEMENTS
The different types of movements that occur at the foot and ankle are dorsiflexion and plantarflexion, inversion and eversion, pronation and supination, adduction and abduction, flexion and extension and circumduction. Since the foot is made up of different types of synovial joints, it means the foot is able to move more freely, in a variety of ways. That is why there are a numerous amount of movements that the foot can perform.
