Metatarsus – structure, functions, role, injuries and diseases of the metatarsus

Proven content

The metatarsus is the five long bones of the foot, located between the toe bones and the tarsal bones. Each metatarsal bone is attached to one of our fingers. They are arranged next to each other in the shape of an arc, which gives the foot an appropriate shape. The metatarsus is important for maintaining balance when standing and walking.

Metatarsus – construction

Metatarsus (lat. metatarsus) is a group of five long bones of the foot located between the tarsal bones and the phalanges of the toes. Due to the lack of individual names, the metatarsal bones were numbered from the medial side (from the big toe): first, second, third, fourth and fifth metatarsal bones (often represented in Roman numerals). The metatarsal bones are analogous to the metacarpal bones of the hand.

First metatarsal bone

The first metatarsal is the thickest and shortest of the metatarsals. There are usually no articular surfaces at the base, but sometimes they appear on the side where they connect to the other metatarsal bone. It connects proximally with the medial wedge bone (Latin. os cuneiform mediale) at the base. The stem has a strong and prismatic shape. Distally, there are two grooved articular surfaces in which the two sesamoid (lat. sesamoid bone) join on the dorsal surface. It also bends distally with the proximal phalanx (Latin. phalanx proximalis).

The muscle attachments of the first metatarsal are:

1. Base – tibial anterior muscle (lat. tibialis anterior muscle) and long fibula (Latin. musculus fibularis sive peroneus longus);
2. Lumpy – long fibula (lat. musculus fibularis sive peroneus longus);
3. Lateral part – the first interosseous dorsal muscle of the foot.

Second metatarsal bone

The second metatarsal bone is the longest of all metatarsal bones and has four articular surfaces at the base. They are connected with the medial, intermediate (Latin. the intermedium cuneiforms) and lateral (Latin. the lateral cuneiforms) the wedge bone, as well as the third metatarsal bone. Sometimes there is a medial articular surface at the base that connects to the first metatarsal bone. It connects distally to the second proximal phalanx.

The muscle attachments of the second metatarsal are:

1. medial shaft – the first dorsal interosseous muscle of the foot;
2. lateral shaft – the second dorsal interosseous muscle of the foot.

Third metatarsal bone

The third metatarsal has a triangular base that connects proximally to the lateral wedge bone. Medially, it has two articular surfaces where it connects to the second metatarsal bone, and laterally connects to the fourth metatarsal bone through a single articular surface. The end of the metatarsal bone connects to the third proximal phalanx.

The muscle attachments of the third metatarsal are:

1. medial shaft – the second dorsal interosseous muscle of the foot and the first plantar interosseous muscle;
2. lateral shaft – the third dorsal interosseous muscle of the foot.

Fourth metatarsal bone

The fourth metatarsal is smaller than the third and has three articular surfaces at the base. Proximally, it has a quadrilateral articular surface that connects to the cubic bone (Latin. the cuboid). In the medial part there is an oval articular surface that connects to the third metatarsal bone, and on the lateral surface there is one more single articular surface that connects to the fifth metatarsal bone. The end of the bone connects distally to the fourth proximal phalanx.

The muscle attachments of the fourth metatarsal are:

1. medial body – the third dorsal interosseous muscle of the foot and the second plantar interosseous muscle;
2. lateral shaft – the fourth dorsal interosseous muscle of the foot.

Fifth metatarsal bone

The fifth metatarsal has a bump on the side of the base that can both be seen and felt along the lateral edge of the foot. The base connects to the cubic bone and the fourth metatarsal bone. The end of the metatarsal bone also connects to the fifth proximal phalanx.

See also: Human skeletal system

Metatarsus – joints

Tarsometatarsal joint

The metatarsal bones connect the ankle with the toes. The metatarsal bones are convex on the dorsal surface but concave on the plantar surface. A proximal base joins one or more distal tarsal bones; namely, a cubic bone and a wedge bone.

Metatarsophalangeal joints

The ends of the metatarsal bones join the corresponding proximal phalanx to form the metatarsophalangeal joints. The end of the first metatarsal also connects to the two navicular navicles on the plantar surface of the foot.

Intermetatarsus joints

In addition, the bases of the metatarsal bones fuse together to form the metatarsal joints. The smooth areas of the metatarsus that connect with other bones are known as articular surfaces (lat. articular facies).

Metatarsus – functions

The metatarsal bones, along with the calcaneus, are involved in supporting the weight of the body. The midfoot has 5 major points of contact with the ground:

1. First metatarsal head and two sesamoid;
2. Second metatarsal head;
3. Third metatarsal head;
4. The fourth head of the metatarsal bone;
5. Fifth metatarsal head.

Most of the load is supported by the thicker first metatarsal, with the second to fifth metatarsal bones providing balance and comfort.

See also: Sclerotization

Metatarsus – diagnosis of metatarsal diseases

X-rays (X-rays) and computed tomography (CT) or magnetic resonance imaging (MRI) images can be used to diagnose acute metatarsal fractures. Most of them can be seen on x-rays.

The doctor also needs to determine if there is a displaced fracture, which may mean that the bones need to be put in place and immobilized.

Stress fractures do not appear as easily on X-rays as an acute metatarsal fracture. Specialized ultrasound, bone scintigraphy, and MRI can show those that cannot be seen on an X-ray.

See also: Fractures of the metatarsal bones and toes

Metatarsus – ailments and injuries

Metatarsal injuries are fairly common, and the most commonly documented are metatarsal fractures, stress fractures, and Lisfranc joint injuries.

Metatarsal fractures

Metatarsal fractures are among the most common foot injuries. In children, the most common metatarsal fracture is the first metatarsal, while the fifth metatarsal is the most common metatarsal fracture in adults. The two main mechanisms of metatarsal fractures are direct crush injuries and indirect rotation mechanisms. Indirect mechanisms are much more common than direct crush injuries and typically involve hindfoot inversion, forefoot adduction, or repeated microtrauma.

Patients present with pain and limitation associated with the load and may resist foot rollover during a physical examination. Palpating this area by hand will cause significant pain. Most metatarsal fractures heal inoperable.

Open fractures, displaced fractures and multiple metatarsal fractures are indications for surgical treatment. Defective fixation of metatarsal bone fractures can lead to metatarsalgia, i.e. pain in the plantar area of ​​the metatarsal heads (metatarsals).

Fracture of the XNUMXth metatarsal bone

Fractures of the XNUMXth metatarsal are the most common fractures of the metatarsal bones in adults. The XNUMXth metatarsal bone can be divided into bone segments. Fractures of the XNUMXth metatarsal are classified according to the location or zone of the fracture.

In the case of a fracture of the XNUMXth metatarsal, consisting in tearing off a small fragment from the end of the bone pointing backwards, we speak of the so-called “Tennis fracture”, that is, an avulsion fracture (from a stroke). Breaking may occur during a tennis game when the player suddenly stops after running to the ball. Such injuries are treated without surgery in a shoe with a hard sole or in walking shoes with controlled ankle movement.

In the case of a fracture at the border of the epiphysis and metatarsal bone close to 1,5 cm from the end of the bone, we can talk about the so-called “Breaking Jones”. The name comes from the surname of Robert Jones, who was the first to describe such a fracture. Healing of this type of fracture is worse than in the previous case due to the location of the injury at the site of poor blood supply to the fifth metatarsal bone. A fracture is usually caused by incorrectly positioning the foot to the side and thus putting too much stress on the XNUMXth metatarsal bone. In professional or competitive athletes, Jones’s fracture can be treated with intramedullary screws to reduce the risk of non-union and accelerate the injured person’s return to sport.

Metatarsal overload fractures

Metatarsal overload fractures are not uncommon. Also known as fatigue fractures, multiple repetitive cycles of deformation lead to micro fractures in the bone. If repeated stress continues, microfractures can occur faster than bone can heal, resulting in a complete fracture.

Metatarsal strain fractures are one of the most common sites of stress fractures in the body, accounting for nearly half of all stress fractures. Treatment of stress fractures is usually conservative, involving a reduction in activity for six to twelve weeks and wearing a hard-soled shoe or dressing.

Lisfranc joint injuries

Lisfranc joint injuries are characterized by a rupture of the joint between the medial wedge bone and the base of the other metatarsal bone, fracture / dislocation of the metatarsal tarsus. This type of injury most often occurs as a result of an injury at the site of a car accident, a fall from a height, or a sports injury due to axial load on the plantar flexion of the forefoot.

Lisfranc injuries can be treated non-surgically by immobilizing the cast when there is no displacement on radiographs with load or stress, or no evidence of bone trauma on computed tomography. Often times, Lisfranc injuries are treated surgically with an open set with internal fixation (ORIF). Rehabilitation is of significant importance in the treatment process, the aim of which is to obtain a fully stable and functional foot.

When the Lisfranc joint injury is characterized by significant displacement of the tarsometatarsal joint, nonsurgical treatment often leads to severe loss of function and long-term disability secondary to chronic pain and sometimes to squamous valgus deformity. In cases of severe pain, loss of function, or progressive deformity that has not responded to non-surgical treatment, arthrodesis of the metatarsus and tarsus (surgical bone fixation) may be indicated.

Gout

Gout is an inflammatory arthritis characterized by high levels of uric acid in the blood and deposits of crystals in the joints and surrounding tissues. The metatarsophalangeal joint of the big toe is often the first joint to suffer from gout. Gout can cause tenderness and swelling in this joint. Osteoarthritis can also cause severe pain in this joint.

Hallux valgus

Hallux valgus (lat. hallux valgus) is a deformation of the foot characterized by a medial curvature of the first metatarsal bone and a lateral deviation of the big toe. It is often caused by osteoarthritis or pressure from the shoes. More common in women, hallux valgus causes an inward shift of the XNUMXst metatarsal and a lateral shift of the sesamoid bone. This causes the sesamoid to lie between the heads of the XNUMXst and XNUMXnd metatarsal bones. When the surrounding tissues swell, a subcutaneous bursa may form. When this bursa is inflamed, it can cause great pain. A painful deformity of the hallux valgus is called a hallux.

Choroba Freiberg

Freiberg’s disease is a rare condition characterized by swelling and fracture of the metatarsal head. Frieberg’s disease is thought to be the result of disruption of blood supply in conditions of microtrauma or bone necrosis. The disease is most common in young athletes, involving the dorsal part of the second metatarsal head.

Treatment may be inoperable with activity restrictions, the use of NSAIDs, and bone immobilization with a short bandage or stiff sole for four to six weeks in the early stages of the disease. However, in more severe cases, surgical intervention may be required.

Metatarsus – injury prevention

There are many things you can do to prevent metatarsal injuries.

1. Increase the intensity and duration of exercise slowly and gradually.
2. Recovery and recovery times should be included in any training schedule.
3. The footwear should fit snugly and match our running style. If we change them – for example, from training shoes to barefoot shoes – we should do it gradually.
4. We should be aware of the symptoms of chronic fractures and not continue running on the sore foot.

If stress fractures are recognized and treated quickly, it can reduce the time it takes to recover and return to physical activity.

See also: It all starts with the feet