Generality
In human beings, the bones of the foot are the skeletal structure of the terminal part of each lower limb. There are a total of 26 and, according to the anatomists, they can be divided into three large groups: the bones of the tarsus (or tarsal or tarsal bones), the metatarsal bones (or metatarsals) and the bones of the toes (or phalanges of the foot).
The bones of the foot have a supporting function, they allow the human being to be a bipedal animal, they form a series of very important joints for the functionality of the foot and, finally, they give insertion to tendons fundamental for locomotion.
Like any bone in the human skeleton, the bones of the foot can also fracture.
What are foot bones?
In the human being, the bones of the foot are what constitutes the skeleton of the terminal part of each lower limb.
Inside the human body, the feet are two fundamental anatomical structures to:
- Ensure stability in the standing position;
- Absorb a good part of your body weight;
- Allow locomotion. Without the feet, the human being would not be able to walk, run, jump etc.
Anatomy
In all 26, the bones of the foot can be divided into three large groups: the bones of the tarsus (or more simply tarsus ), the metatarsal bones (or metatarsals ) and the bones of the toes (or phalanges of the foot ).
The bones of the tarsus are 7 and represent the proximal portion of the skeleton of the foot; the metatarsal bones are 5 and represent the intermediate portion of the foot skeleton; finally, the phalanges of the foot are 14 and represent the distal portion of the foot skeleton.
In anatomy, proximal and distal are two terms with the opposite meaning.
Proximal means "closer to the center of the body" or "closer to the point of origin". Referring to the femur, for example, it indicates the portion of this bone closest to the trunk.
Distal, on the other hand, means "farther from the center of the body" or "farther from the point of origin". Referred (always to the femur), for example, it indicates the portion of this bone furthest from the trunk (and closer to the knee joint).
BONE OF TARSO
The tarsus bones, also known as tarsal bones, are irregularly shaped bones that form a compact structure between the distal ends of the tibia and the fibula and the proximal ends of the metatarsal bones.
The bones of the foot that form the tarsus are: the talus, the calcaneus, the navicular bone, the cuboid bone, the lateral cuneiform bone, the intermediate cuneiform bone and the medial cuneiform bone.
- The talus and the calcaneus represent the most proximal bones of the tarsus and play a fundamental role in the formation of the ankle, that is the joint that allows dorsiflexion, plantarflexion, eversion and inversion of the foot.
In this case, the astragalus takes place, with its upper margin, inside the concavity deriving from the particular anatomy of the distal extremities of tibia and fibula; this concavity is called a mortar .
The heel, instead, participates in the articulation of the ankle giving insertion to some extremely important ligaments for the correct functioning of the aforesaid articular element; the ligaments in question are the tibio-calcaneal ligament and the calcaneo-fibular ligament .
Together, talus and calcaneus form the back of the foot (or hindfoot).
- The navicular is the intermediate bone of the tarsus; it resides anteriorly to the astragalus, posteriorly to the three cuneiforms and laterally to the cuboid. It has a protuberance, which serves to insert into a tendon, called the posterior tibial tendon .
- The cuboid and the three cuneiforms are the most distal bones of the tarsus.
Looking like a cube, the cuboid bone occupies a lateral position with respect to the three cuneiforms and borders with the calcaneus, posteriorly, and with the two outer metatarsal bones (fourth and fifth metatarsal), anteriorly.
Looking like a wedge, the three cuneiforms (lateral, intermediate and medial) reside in front of the navicular bone and behind the three inner metatarsals (first, second and third metatarsus).
The particular arrangement of the three cuneiforms and the cuboid allows the neighboring metatarsal bones to constitute the so-called transverse arch of the foot .
BONE METATARSALS
Metatarsal bones, or metatarsals, are long bones, arranged parallel to each other, in which it is possible to distinguish three regions: a central region, called the body ; a proximal region, called the base ; finally, a distal region, identified with the term head .
The base of the metatarsus borders on the bones of the tarsus: starting from the inner side of the foot, the first three metatarsals adhere, one each, to one and only one of the three cuneiforms (the first metatarsal to the medial cuneiform, the second metatarsal to the intermediate cuneiform and the third metatarsal to the lateral cuneiform), while the last two metatarsals (fourth and fifth metatarsus) adhere to the cuboid bone.
The head of each metatarsal borders on the first phalanx of each toe: as a result, each metatarsus corresponds to a toe.
Between the base of the metatarsals and the bones of the tarsus there are a series of joints, as well as between the head of the metatarsals and the first phalanges of the foot.
FALANGES OF THE FOOT
Cylindrical in shape, the phalanges of the foot are the skeleton of the 5 toes.
Except the first finger - the only one formed by 2 phalanges - all the other toes have 3 phalanges each.
The phalanges closest to the metatarsal head are called the first phalanges (or proximal phalanges ); starting from these, the following are called second phalanges (or intermediate phalanges ) and third phalanges (or distal phalanges ).
Between each phalanx there is a joint, which gives the fingers a certain mobility.
Note : in the first toe, the numbering of the phalanges ends with the second phalanges.
Function
The bones of the foot have a supporting function, allowing the standing position on two limbs; form fundamental joints to the foot's function; give insertion to ligaments that are an integral part of the aforementioned joints; finally, they give insertion to tendons very important for locomotion, such as the Achilles tendon .
diseases
Like all bones in the body, the bones of the foot can also fracture.
There are three types of fractures on the bones of the foot: fractures of the bones of the tarsus, fractures of the metatarsus (or metatarsal fractures) and phalangeal fractures.
FRACTURE OF A BONE OF TARSO
Fractures of the foot bones in the tarsus may be of a traumatic nature (in most cases) or due to excessive stress (minority of cases).
Among the bones of the tarsus most subject to traumatic fractures are the talus and calcaneus.
Among the bones of the tarsus most subject to stress fractures are the navicular bone and the heel again.
Individuals who are victims of a traumatic tarsal fracture must wear plaster - clearly on the fractured foot - for at least 6 weeks and avoid giving weight to the limb with a fracture during this time.
Those who are victims of a stress fracture to the tarsal bones may limit themselves to the use of a brace or crutch to limit the weight of the tarsus during walking.
The clinical manifestations typical of a fracture of a tarsal bone are foot pain and lameness.
For an accurate diagnosis, X-ray examination of the painful foot, physical examination and medical history are essential.
METATARSUS FRACTURE
Metatarsals are bones of the foot that can be broken in at least three different ways:
- As a result of a violent blow, directed on the back foot. This is the case, for example, of a heavy object falling on the foot.
Metatarsal fractures due to violent shocks are the most common.
- Due to a stress factor that affects the foot in general or a part of it in particular. This type of fracture is called metatarsal stress fracture and mainly affects the metatarsals of the 2nd, 3rd and 4th finger. It is very common among good athletes and is generally a microfracture .
- Due to excessive foot inversion movement. With a violent and very marked inversion of the foot, the short peroneal muscle could "pull" the metatarsal of the 5th finger and cause its rupture.
The typical clinical manifestations of a metatarsal fracture are: fractured foot pain and lameness.
For a certain diagnosis, X-ray examination of the foot is essential.
The treatment of metatarsal fractures varies depending on the site of the bone rupture and whether the latter is composed or decomposed.
In fact, in certain cases, rest and immobilization of the lower limb could suffice; in others, on the other hand, it may be necessary to have surgery to weld the bone fracture.
FRACTURE OF A FOOT FALANGE
Fractures of one or more phalanges of the foot are conditions of mild gravity, which arise as a result of traumatic events that damage the toes. In general, the treatment of fractures of the toes constituting the toes consists of a rest period of 20-30 days.
