Generality
The ankle is the synovial joint of the human body, located at the distal ends of the fibula and tibia (leg bones) and at the proximal end of the talo (one of the 7 tarsal bone elements of the foot).
The ankle has a complex system of ligaments: the medial ligaments, which are a total of 4, and the lateral ligaments, which are altogether 3.
These structures, together with the peron-tibia-talo synergism, allow the foot to perform two opposite movements: dorsiflexion and plantarflexion.
Dorsiflexion is when you lift your feet and walk on your heels; plantarflexion, on the other hand, is when you stand up on your toes.
Distortions are very common injuries to the ankle joint. Following a sprain, the ankle ligaments can be stretched or broken.
What is the ankle?
The ankle is the synovial joint of the human body, located between the leg and foot, exactly at the meeting point of three bones: tibia, fibula and talo (or astragalus ).
The tibia and fibula are the two bones that make up the leg; the talo, on the other hand, is one of the seven bones that form the tarsal group of the foot.
BRIEF ANATOMICAL RECALL OF THE FOOT
The anatomists divide the bones of the foot into three groups: the tarsal bones (or tarsal group), the metatarsal bones (or metatarsal group) and the phalanges .
The metatarsal bones are 5, arranged parallel to each other. They are long bones, at the ends of which the phalanges are articulated.
Finally, the phalanges are 14 and form the toes. Except for the big toe which is made up of 2 phalanges, all the other toes have 3 for each.
PUNCTUALIZATION ON THE MEANING OF THE ANKLE
The definition of ankle, given a little earlier, is the one known to most and is used in common speech.
However, it should be pointed out that, in the purely medical-anatomical language, the term ankle identifies the set of three joints: the talocrural (or tibio-tarsal) articulation, the subthalar joint and the inferior tibio-fibular articulation (or lower tibio-peroneal).
Of these three articular elements, the talocrural articulation corresponds to the ankle in the common language; in fact it is also known ankle properly so called .
EXAMPLE OF DIARTROSI
The ankle is an example of a mobile joint or diarthrosis . These joints allow a wide range of movement, in one or more directions of space.
Other examples of diarthrosis are the knee, shoulder and fingers.
Anatomy
The ankle joint connects the distal ends of the tibia and fibula with the proximal end of the talo:
- Held together by the inferior tibio-fibular ligaments (anterior and posterior), the extremities of tibia and fibula form, on the lower margin, a concave hoof, called mortar and covered with cartilage.
- The talo fits into the mortar with its own region, which takes the name of the body.
The body of the talo has a conical shape; in fact, it is wide at the front (front) and narrow at the back (rear).
To stabilize this bone arrangement, there are a series of ligaments (which will be treated separately) and the two malleoli, the tibial and the peroneal.
The tibial malleolus and the peroneal malleolus are two bone processes, located, respectively, on the medial margin of the tibia and on the lateral margin of the fibula. It is no coincidence that the tibial malleolus also takes the name of medial malleolus, while the peroneal malleolus also takes the second word of lateral malleolus.
LIGAMENTS
To hold together the bony ends constituting the ankle, there are two groups of ligaments :
- The medial or deltoid ligaments . The medial ligaments are four separate elements, which join the tibial / medial malleolus to the talo in two points (anterior talo-tibial ligament and posterior talo-tibial ligament), to the calcaneus (tibio-calcaneal ligament) and to the navicular bone (tibial ligament- navicular).
- Lateral ligaments . The lateral ligaments are three separate elements, which join the peroneal / lateral malleolus to the talo in two points (anterior talo-fibular ligaments and posterior-fibular ligaments) and to the calcaneus (calcaneo-fibular ligament).
TENDONS
To give support to the ankle, several tendons participate. From a structural point of view, a tendon looks a lot like a ligament; the only (and substantial) difference from the latter is that it connects a muscle to a bone (NB: a ligament puts in bonds two bones).
The tendons in close contact with the ankle joint are:
- The Achilles tendon . Connect the calf muscles (the twins and the soleus) to the calcaneal bone. It is essential for walking, running and jumping. His break severely limits a person's motor skills.
- The anterior tibial tendon . Connects the tibialis anterior muscle to a tarsal bone of the foot, located in the medial position.
- The posterior tibial tendon . It joins the posterior tibial muscle to the tarsal bones.
- Peroneal tendons . They connect the peroneal muscles to the lateral bones of the tarsal region of the foot. They slide sideways to the ankle.
NERVES
At least three nerves pass by the ankle.
The most important is the tibial nerve, a derivation (or branch) of the sciatic nerve that runs through the posterior compartment of the leg and reaches the sole of the foot.
The other two nerves pass, one in front of the ankle and another on its lateral edge.
Functions
The ankle allows the foot to perform two fundamental and opposite movements: plantarflexion and dorsiflexion .
Plantarflexion is the movement that allows you to point your foot towards the floor. The human being performs a plantarflexion movement when he tries to walk on his toes.
Dorsiflexion, on the other hand, is the movement that allows you to lift your foot and walk on your heels.
Both of these movements require the involvement of different muscles; In the case:
- For the plantarflexion movement, serve the twin muscles (of the calf), the soleus muscle (of the calf), the plantar muscle and the posterior tibial muscle.
- For the dorsiflexion movement, serve the tibialis anterior muscle, the extensor muscle of the big toe and the extensor muscle of the fingers.
* Please note: the reader may notice that some of the muscles involved in the ankle movements are the same as those mentioned previously, when the tendons were discussed.
SIDE MOVEMENTS
In reality, thanks to its ligaments, the ankle also enjoys some lateral mobility . This property guarantees the human being to walk on uneven surfaces.
Clearly, it has limits, which, if exceeded, can cause stretching or damage to the ankle ligaments.
Ankle Diseases
The most common problems that can affect the ankle are stretching and breaking of the ligaments that join the various bone parts involved in the joint.
These two conditions take the general name of ankle sprain, with reference to the fact that often the stretching and the breaking of the ligaments is a consequence of an anomalous movement of the joint.
The ligaments most involved in the sprains are the lateral ligaments, as the latter are weaker than the medial ligaments.
ANKLE FRACTURE
Another major injury that the ankle can suffer - though less frequently than sprains - is Pott's so-called bimalleolar or trimalleolar fracture .
In general, this ankle injury is the result of a marked movement of the foot.
