Metacarpal bone: structure, function, injury
The metacarpal bone is a bone in the form of a tube that is placed on or on the foot. On one human hand or foot, there should be five such bones, which depart in the form of a beam and have their own, special structure. Between themselves, these bones are connected by joints and tendons. It is on the condition in which the metacarpal bones are located, and the mobility of the entire hand or foot will depend.
Functions of the metacarpals
The main function for which these bones are responsible is, of course, mobility, with the help of which the fingers and toes can bend and unbend, ensuring unhindered movement. Everyone understands perfectly well that without movement of the arms, he cannot feel full, therefore any injuries and abnormalities in these bones can lead to difficulties with movements, and in some cases even to disability, which occurs if the victim has not been given timely and qualified professional assistance.
Structure of the metacarpal bone
First of all, it is necessary to clearly know how many metacarpal bones exist in humans. On one foot or hand you can count five such tubular bones. All of them are attached thanks to the interosseous muscles, which ensures further movement of the motility, and the tendons that make the fingers move are also important. Any body of the metacarpal bone passes into the neck, later into the head, and then connects with the phalanx of the finger. There is a weak spot in this bone, this is the neck, this is where the most injuries occur.
Consider each bone of the arm separately:
- The first bone is considered to be from the thumb, so it differs from the others in that it is shorter and slightly thicker than the others. A special feature can be considered the fact that this metacarpal bone of the hand is connected with the wrist using different extreme angles.
- The second and third metacarpals in all parameters are considered the most durable, because they are rigidly attached to the wrist with their base.
- The fourth and fifth bones are attached more freely, which makes it possible for the hand to move freely and grab different objects in shape and in gravity.
What is the base of the bone
It is important to pay attention to the structure of the third metacarpal bone. The base of the metacarpal bone has a special styloid process. At the bottom of each metacarpal bone is a spherical head. The side surfaces are rough, they are not difficult to feel and feel. Injuries can spread to any part of the metacarpal bone, for example, a fracture of the head, neck, body and even the very base can occur.
The structure of the metacarpal bones
Any metacarpal bone has a slightly curved shape, you can count them starting with the thumb on the hand and the foot. Each bone must include the epiphysis and the body. The body has its own structure, which consists of three different surfaces: the side, medial and back. Between the lateral and medial surface there is a comb, which divides the tubular bones among themselves. In the scallop there is a hole that leads to the most nutrient canal.
Special attention should be paid to the side surface. It is located directly near the base of the body of the metacarpal bone and interconnects all the articular areas.The body of the metacarpal bone arches in the back side. It should be noted that it is not difficult to probe the metacarpal bones, since the body can be felt even through the surface of the skin of the hand or foot.
What symptoms indicate trauma to the metacarpal bone?
There are many reasons for injuries in the region of the metacarpal bone, but the symptoms that accompany any injury are always identical:
- There are severe pain in the area of the fracture.
- You can observe the cyanosis of the skin and severe swelling.
- If the metacarpal bone of the foot has suffered, it is painful for the person to step on the foot, which significantly slows down his movement.
- The finger may become shorter, there is in some cases a deformation, for example, the knuckle may not be palpable at all or even absent.
- A large bruise appears as hemorrhage occurs under the skin.
How can diagnose trauma of the metacarpal bone?
Any injury requires an immediate appeal to a specialist who can accurately determine where the fracture occurred, as a rule, such a specialist is a traumatologist. To determine the location of the fracture, an x-ray is prescribed.Initially, the traumatologist interviews the patient, while the victim tells exactly how he was injured, so the doctor can determine the nature of the injury.
Traumatologist necessarily conducts the inspection, as often the deformity can be identified even with the naked eye, for example, in the event that there was a fracture with displacement. Sometimes a fracture of the metacarpal bone may be accompanied by rotation, when the finger rotates around its axis. For an accurate diagnosis, an x-ray is required, and it is important to remember that the X-ray should be in three protections: straight, side, oblique.
Trauma can include not only a fracture, but also a dislocation, so the traumatologist can also identify such a violation. As a rule, the dislocation goes along with a torn ligament, therefore the bone that has shifted is set back and fixed to strengthen the plaster cast. If the dislocation is repeated again, then the operation requires the insertion of special retaining needles.
Characteristic fracture of the base of the metacarpal bone
If there is a fracture of the base of the metacarpal bone, then first of all it is necessary to eliminate the displacement, for example, with a displacement of 2 mm, angular deformation may occur.The fracture of the fifth metacarpal bone is especially dangerous, as in most cases urgent surgical intervention is required.
The victim will be able to feel better only after a month, when his fingers can already be actively moved, but, despite this, it is recommended to perform not complicated movements during the entire period of immobilization. The fracture of the body of the metacarpal is also difficult, in which case the treatment can be conservative. Most often, the metacarpal bones at numbers three and four are subjected to such fractures, but displacement in this case occurs extremely rarely.
What is the danger of cervical bone injury?
A fracture of the metacarpal bone in the neck is often referred to as impacted. With a strong blow, the head during the fracture is simply hammered into the body and is fixed in this position, but sometimes this condition can even be considered successful, since no displacement occurs and the bone remains in place. The downside is that the bone can be strongly pressed into the body, and the finger will become much shorter, such an injury can be identified with the naked eye.
If the bone has a small angle of deviation, then such a fracture can be cured by conservative methods, with a large deviation it is necessary to carry out the operation.If you do not take measures to treat such a fracture in time, then serious consequences can occur, for example, the ability to perform the basic functions of the bone is impaired, and with active movement, pain will constantly arise.
Bone head fracture
The metacarpal bone may suffer due to a strong blow, especially if this blow falls on the head of a bone that passes through the entire articular surface. If the fracture is without displacement, then it can be cured by conservative methods, while the rehabilitation period is only about a month, after which the joint can be developed, gradually increasing the load. Complications can be in the event that the fracture occurred with displacement or it turned out to be multi-fragment, as a rule, the treatment will be effective only after the operation.
The tubular bones can be fragile, so you should always remember about preventive measures and try to strengthen them in every way. But cases in life can be completely different, so it is not always possible to avoid injuries, one way or another, an immediate response and a long rehabilitation period will be required. If everything is done on time, then the prognosis for recovery will be favorable and after a while the victim will not even remember his problem.Also dangerous is a fracture with damage to the tendons, as this place may decay and infection will begin to develop.
Everyone knows that the metacarpal bones of the hand are the main organ of labor, therefore, the sooner there is an opportunity to restore motor function, the person will soon be able to feel his usefulness. With the wrong and untimely treatment, a fracture that has grown together incorrectly will cause a huge number of problems, which will significantly limit the movement of the joints. It is important to remember that after the operation, treatment and rehabilitation are prescribed only by the attending physician, it is not necessary to self-medicate and ignore the problem. In case of minor injuries, the metacarpal bone can recover within a month, if the injury is with complications, then rehabilitation and treatment can take about 8 weeks. If implants were used, they can be removed a year later, after the bones are well fused.