joints of the foot

The tibiofibular joints are the articulations between the tibia and fibula, which are the two bones of the lower leg. There are three tibiofibular joints:

1. **Superior Tibiofibular Joint:**

- Type: Synovial joint (plane type).

- Location: Between the head of the fibula and the lateral condyle of the tibia.

- Communication: It may communicate with the knee joint through the popliteal bursa.

- Function: This joint allows for some gliding or rotatory movements that help in adjusting the lateral malleolus during movements at the ankle joint, such as during dorsiflexion.

2. **Middle Tibiofibular Joint:**

- Type: Fibrous joint.

- Structure: This joint is formed by the interosseous membrane that connects the interosseous borders of the shafts of the tibia and fibula.

- Fibre Orientation: The fibres of the interosseous membrane are directed downward and laterally. It is wide above and narrows below, where it blends with the interosseous ligament of the inferior tibiofibular joint.

- Openings: A large opening above the upper free margin of the interosseous membrane provides passage for the anterior tibial vessels, and there is a small opening near its lower end for the passage of a perforating branch of the peroneal artery.

- Functions: The interosseous membrane serves several functions, including providing additional surfaces for muscle attachment, binding the tibia and fibula, and resisting the downward movement of the fibula due to the action of the fibular muscles.

3. **Inferior Tibiofibular Joint:**

- Type: Syndesmosis (a type of fibrous joint).

- Structure: This joint consists of the interosseous ligament, which is a very strong ligament connecting the roughened surfaces of the lower ends of the tibia and fibula.

- Ligaments: The interosseous ligament is covered both in front and behind by the anterior and posterior tibiofibular ligaments, respectively. The posterior tibiofibular ligament is stronger than the anterior tibiofibular ligament. The lower and deep portion of the interosseous ligament forms the inferior transverse tibiofibular ligament, a strong and thick band of yellowish elastic fibers that passes transversely from the upper part of the malleolar fossa to the posterior border of the tibial articular surface.

- Function: The inferior tibiofibular joint permits slight movements, which allow the lateral malleolus to rotate laterally during dorsiflexion of the ankle. The strength and integrity of this joint are crucial for the stability and function of the ankle joint.

These tibiofibular joints provide stability and enable specific movements of the lower leg bones, contributing to the overall function of the knee and ankle joints.

Here is a comparison of the superior, middle, and inferior tibiofibular joints:

**Superior Tibiofibular Joint:**

- Type: Plane type of synovial joint.

- Formation: Formed by the articulation between the oval articular facet on the lateral condyle of the tibia and a similar facet on the head of the fibula.

- Functions: Permits some gliding movements. Allows for some rotation of the fibula during dorsiflexion of the knee.

- Accentuates: It does not accentuate the "tibiofibular mortise."

**Middle Tibiofibular Joint:**

- Type: Fibrous joint.

- Formation: Formed by the union of the interosseous border of the tibia and fibula by an interosseous membrane.

- Functions: Permits rotation of the fibula during dorsiflexion of the knee.

**Inferior Tibiofibular Joint:**

- Type: Syndesmosis variety of the fibrous joint.

- Formation: Formed by the union of the rough triangular surface of the lower ends of the tibia and fibula by a strong interosseous ligament and anterior and posterior tibiofibular ligaments.

- Functions: Accentuates the "tibiofibular mortise" and allows lateral rotation of the lateral malleolus during dorsiflexion.

- Innervation: Innervated by the deep peroneal, tibial, and saphenous nerves.

Each of these joints serves specific functions and plays a role in the stability and mobility of the lower leg and ankle.

The ankle joint, also known as the talocrural joint, is an important weight-bearing hinge joint of the lower limb. Here are some key points about the ankle joint:

**Type of Joint:**

- The ankle joint is a synovial joint of the hinge variety. This means it primarily allows movement in one plane, similar to the hinge of a door, allowing dorsiflexion (bringing the foot upward) and plantar flexion (pointing the foot downward).

**Articular Surfaces:**

- The proximal articular surface of the ankle joint is formed by the lower end of the tibia, including its medial malleolus, the lateral malleolus, and the inferior transverse tibiofibular ligament. Together, they create a deep socket called the "tibiofibular mortise."

- The distal articular surface of the ankle joint is formed by the articular facets on the upper, medial, and lateral aspects of the body of the talus, a bone in the foot. The wedge-shaped talus fits into the tibiofibular mortise created by the tibia and fibula.

**Stability of the Ankle Joint:**

- The trochlear surface on the superior aspect of the talus is wider in the front than in the back. During dorsiflexion (raising the toes), the anterior wider part of the trochlea moves posteriorly and fits properly into the tibiofibular mortise, providing stability.

- However, during plantar flexion (pointing the toes downward), the narrow posterior part of the trochlea does not fit properly into the tibiofibular mortise, making the joint unstable during plantar flexion.

**Factors Maintaining Stability:**

- The stability of the ankle joint is maintained by factors such as the close interlocking of its articular surfaces, strong medial and lateral collateral ligaments, the deepening of the tibiofibular socket posteriorly by the inferior transverse tibiofibular ligament, tendons that cross the ankle joint, and other ligaments.

The ankle joint is crucial for maintaining balance, supporting the body's weight, and facilitating walking and various activities. It's a key joint in the lower limb, and its stability is essential for proper function.

The ankle joint is supported and stabilized by several ligaments, both on the medial (deltoid ligament) and lateral (lateral ligament) sides. Here's an overview of these ligaments:

**Capsular Ligament:**

- The capsular ligament surrounds the ankle joint entirely, attaching to the articular margins of the joint.

- It is thin in front and behind to allow hinge movements but thick on the sides, where it blends with the collateral ligaments.

- A synovial membrane lines the inner surface of the joint capsule but ceases at the periphery of the articular cartilages. It extends upward into the inferior tibiofibular syndesmosis.

**Deltoid or Medial Ligament:**

- The deltoid ligament is a strong triangular ligament on the medial (inner) side of the ankle.

- It consists of both superficial and deep parts.

- The common attachment of both parts is at the apex and margins of the medial malleolus (the bony prominence on the inner side of the ankle).

- The superficial part has three divisions: anterior, middle, and posterior.

- The anterior fibers attach to the tuberosity of the navicular bone and the medial margin of the spring ligament.

- The middle fibers attach to the whole length of the sustentaculum tali, a bony structure on the inner side of the foot.

- The posterior fibers are attached to the medial tubercle and the adjoining part of the medial surface of the talus, one of the bones of the ankle joint.

- The deep part of the deltoid ligament is attached to the anterior part of the medial surface of the talus.

**Lateral Ligament:**

- The lateral ligament consists of three parts:

1. Anterior talofibular ligament: A weak, flat band extending forward and medially from the anterior margin of the lateral malleolus (the outer bony prominence of the ankle) to the neck of the talus, just in front of the fibular facet.

2. Posterior talofibular ligament: A strong band that extends backward and medially from the posterior margin of the lateral malleolus to the posterior tubercle of the talus.

3. Calcaneofibular ligament: A long, rounded cord that runs downward and backward from the notch on the lower border of the lateral malleolus to the tubercle on the lateral surface of the calcaneum (heel bone).

The ankle joint is a synovial hinge joint that allows for dorsiflexion and plantar flexion of the foot. Here are some key points related to the ankle joint:

**Anterior Relations:**

- Anteriorly, the ankle joint is related to several structures, listed from medial to lateral:

1. Tibialis anterior muscle.

2. Extensor hallucis longus muscle.

3. Anterior tibial artery.

4. Deep peroneal nerve.

5. Extensor digitorum longus muscle.

6. Peroneus tertius muscle.

You can use the mnemonic "The Himalayas Are Not Dry Plateaus" to remember these structures.

**Posterior Relations:**

- Posteriorly, the ankle joint is related to the following structures, again listed from medial to lateral:

1. Tibialis posterior muscle.

2. Flexor digitorum longus muscle.

3. Posterior tibial artery.

4. Posterior tibial nerve.

5. Flexor hallucis longus muscle.

You can use the mnemonic "The Doctors Are Not Here" to remember these structures.

**Arterial Supply:**

- Blood supply to the ankle joint is provided by the malleolar branches of the anterior tibial, posterior tibial, and peroneal arteries.

**Nerve Supply:**

- Nerve supply to the ankle joint comes from branches of the deep peroneal and tibial nerves. The segmental innervation for the ankle joint is by spinal segments L4, L5, S1, and S2.

**Movements:**

- The primary movements at the ankle joint are dorsiflexion and plantar flexion.

- In dorsiflexion, the forefoot is raised, and the angle between the front of the leg and the dorsum of the foot decreases. The ankle joint is most stable in dorsiflexion.

- In plantar flexion, the forefoot is depressed, and the angle between the leg and the foot increases. The ankle joint is unstable in plantar flexion.

- When the foot is plantar flexed, the joint also permits some degree of side-to-side gliding, rotation, adduction, and abduction.

- The range of motion (ROM) for dorsiflexion is approximately 20°, while the ROM for plantar flexion is about 45°.

The dorsiflexion of the ankle joint is primarily controlled by spinal segments L4 and L5, while plantar flexion is controlled by segments S1 and S2.

**Ankle Sprains:**

- Ankle sprains occur when the ligaments of the ankle joint are excessively stretched and/or torn.

- Inversion sprains, where the plantar-flexed foot is excessively inverted, are more common than eversion sprains.

- Commonly injured ligaments include the anterior and posterior talofibular ligaments and the calcaneofibular ligament.

- In inversion sprains, the anterior talofibular ligament is most commonly torn. When the foot is excessively everted, the deltoid ligament is not torn, and an avulsion fracture of the medial malleolus may occur.

**Dislocation of the Ankle:**

- Dislocations of the ankle joint are rare due to the joint's stability, primarily because of the tibiofibular mortise.

- When ankle dislocations do occur, they are often accompanied by fractures of one of the malleoli.

**Pott's Fracture (Fracture-Dislocation of the Ankle):**

- Pott's fracture is a severe injury that occurs when the foot is forcibly caught in an everted position, often as a result of trauma.

- The sequence of events in Pott's fracture typically involves:

1. An oblique fracture of the lateral malleolus due to internal rotation of the tibia.

2. A transverse fracture of the medial malleolus due to the pull of the strong deltoid ligament.

3. A fracture of the posterior margin of the lower end of the tibia, sometimes referred to as the third malleolus, as it is carried forward. This stage is also known as the trimalleolar fracture.

**Optimum Position of the Ankle:**

- The optimum position of the ankle is one in which the ankle joint is in slight plantar flexion. This knowledge of the position is essential when applying a plaster cast or other treatments in the ankle region.

Ankle injuries and conditions can range from minor sprains to more severe fractures and dislocations. Proper diagnosis and treatment are essential to promote healing and maintain the stability and function of the ankle joint.

The foot has several joints that play essential roles in its function and stability. Here are some key details about the major intertarsal joints in the foot:

**1. Subtalar (Talocalcanean) Joints:**

- The subtalar joint consists of two components: the posterior talocalcanean joint and the anterior talocalcaneonavicular joint. The posterior component is often referred to as the subtalar joint.

- It is a plane-type synovial joint.

- The joint is formed between the concave facet on the inferior surface of the talus and the convex facet on the superior surface of the calcaneum.

- Several ligaments contribute to the stability of the subtalar joint, including the lateral and medial talocalcanean ligaments, interosseous talocalcanean ligament, and cervical ligament.

- The interosseous talocalcanean ligament separates the subtalar joint from the talocalcaneonavicular joint, and it becomes taut during eversion.

- The cervical ligament extends upward and medially from the calcaneum to the inferolateral aspect of the neck of the talus, becoming taut during inversion.

- The subtalar joint plays a significant role in foot inversion and eversion.

**2. Talocalcaneonavicular Joint:**

- The talocalcaneonavicular joint is a compound articulation composed of the anterior talocalcanean and talonavicular joints.

- It is roughly a ball-and-socket type of synovial joint.

- The rounded head of the talus articulates with a socket formed by the calcaneum, navicular, and spring ligament.

- Ligaments that support this joint include the fibrous capsule, spring ligament, and the medial limb (calcaneonavicular part) of the bifurcate ligament.

- The spring ligament is crucial for maintaining the medial longitudinal arch and contains a fibrocartilaginous facet for the talus on its upper surface.

- The talocalcaneonavicular joint allows for inversion and eversion movements of the foot.

**3. Calcaneocuboid Joint:**

- The calcaneocuboid joint is a saddle-type synovial joint.

- It involves articulation between the calcaneum and the cuboid, with reciprocally concavoconvex articular surfaces.

- Ligaments supporting this joint include the fibrous capsule, lateral limb (calcaneocuboid part) of the bifurcate ligament, long plantar ligament, and short plantar ligament.

- The long plantar ligament extends from the calcaneum to the bases of the middle three metatarsals and plays a crucial role in maintaining the foot's arches.

- The short plantar ligament extends from the calcaneum to the cuboid, providing further support.

- The calcaneocuboid joint is essential for proper foot function and gait.

**4. Transverse Tarsal (Midtarsal) Joint:**

- The transverse tarsal joint, also known as the midtarsal joint, is a compound joint formed by the combination of the calcaneocuboid and talonavicular joints.

- These joints are located in nearly the same transverse plane and work together in foot movements.

- While both joints contribute to inversion and eversion, they have different axes of motion, making the midtarsal joint essential for the complex movement of the foot during gait and other activities.

These intertarsal joints play a crucial role in the flexibility, stability, and functionality of the human foot. They contribute to various movements and help support the arches of the foot during weight-bearing activities.

Inversion and eversion are important movements of the foot that involve the tilting of the sole of the foot toward the midline (inversion) or away from the midline (eversion). These movements are crucial for various activities, such as walking on uneven surfaces, maintaining balance, and adapting to changes in terrain.

**Joints Involved in Inversion and Eversion:**

1. **Subtalar Joint:** The subtalar joint primarily facilitates inversion and eversion of the foot. It is responsible for most of the inversion and eversion movements.

2. **Talocalcaneonavicular Joint:** The talocalcaneonavicular joint plays a significant role in these movements. It is involved in subtler adjustments and is crucial for maintaining the foot's arches and stability.

3. **Transverse Tarsal (Midtarsal) Joint:** This joint also contributes to inversion and eversion but to a lesser extent compared to the subtalar joint. It is more involved in fine-tuning these movements.

**Axis of Movements:**

- Inversion and eversion occur around an oblique axis that runs forward, upward, and medially. This axis passes from the back of the calcaneum through the sinus tarsi and emerges at the superomedial aspect of the neck of the talus. This oblique axis allows for the multi-planar movements of the foot during inversion and eversion.

**Range of Movements (ROM):**

1. The range of movement for inversion is generally greater than that for eversion. Inversion can typically reach approximately 30 degrees, while eversion has a range of around 20 degrees.

2. The range of these movements is increased when the foot is in a plantar-flexed position. In plantar flexion, the narrow posterior part of the trochlear surface of the talus fits into the tibiofibular socket (mortise), allowing for more side-to-side movement of the talus.

**Muscles Producing Inversion and Eversion:**

- Various muscles play a role in the movements of inversion and eversion. For inversion, muscles include the tibialis anterior, tibialis posterior, and flexor digitorum longus. For eversion, muscles include the peroneus longus, peroneus brevis, and peroneus tertius.

**Functional Significance:**

- Inversion and eversion movements are necessary for adapting to uneven or sloping terrain. They help the foot maintain stability and balance when walking on surfaces that are not perfectly flat.

- In weight-bearing situations, inversion and eversion movements become modified forms known as supination and pronation. These movements are essential for absorbing shock and maintaining balance during activities like walking and running.

These movements and associated joints and muscles contribute to the foot's flexibility, adaptability, and ability to handle a variety of terrains and weight-bearing activities.

The joints of the foot, including the tarsometatarsal joints, metatarsophalangeal joints, and interphalangeal joints, provide flexibility and support for various movements and activities. Here's an overview of these foot joints:

**Tarsometatarsal Joints:**

- There are five tarsometatarsal joints in the foot.

- These are plane-type synovial joints that allow limited gliding movements.

- They are connected by dorsal, plantar, and interosseous tarsometatarsal ligaments.

- The first tarsometatarsal joint has a separate cavity, while the second and third joints share a single cavity.

**Metatarsophalangeal Joints:**

- The metatarsophalangeal joints are ellipsoidal-type synovial joints located between the metatarsal bones and the proximal phalanges of the toes.

- These joints permit slight gliding movements.

- They are connected by capsular, collateral, plantar, and deep transverse metatarsal ligaments.

- Two collateral ligaments strengthen the sides of each joint.

- The deep transverse ligaments (four in number) connect the plantar ligaments of adjacent metatarsophalangeal joints.

- The metatarsophalangeal joints allow dorsiflexion, plantar flexion, adduction, and abduction of the toes.

- The range of dorsiflexion (50–60°) is greater than that of plantar flexion (30–40°).

- The axis of adduction and abduction of the toes passes through the second metatarsal bone, making it the least mobile metatarsal.

- This is analogous to the axis of adduction and abduction in the fingers, which passes through the third metacarpal bone.

**Interphalangeal Joints:**

- These are typical hinge joints located between the phalanges (toe bones) of the foot.

- Interphalangeal joints permit dorsiflexion and plantar flexion of the distal phalanges.

These foot joints provide essential mobility for various activities such as walking, running, and maintaining balance. The movements and flexibility of these joints are crucial for proper gait and function of the foot.