Good afternoon, dear anatomy lovers. We continue to study the lower limb in detail. In the last article we studied the femur and patella. The femur is the skeleton of the hip, and the patella is an important component of the knee joint. Now we go down to the lower leg and study the bones that form it.
So, the lower leg (crus) is the part of the free upper limb, which is located between the thigh and foot. The bone base of the lower leg is formed by two bones - the tibia (tibia) and fibula (fibula).
Tibia fracture
A fracture of the tibia occurs due to the impact of great force on the body of the bone and occurs at different levels. This often happens during road traffic accidents. Of all fractures of the musculoskeletal system, tibial fractures account for 23% of the total number of musculoskeletal injuries.
Classification of tibial fractures
Fractures of the bone diaphysis are classified into transverse, oblique, comminuted, fragmentary and intra-articular. Intra-articular fractures of the tibia include fractures of the tibial condyles and fractures of the medial (inner malleolus). The medial malleolus is the medial bony stabilizer of the ankle joint and fractures occur during twisting (rotation) of the leg with a fixed foot. Also often, a fracture of the inner (medial) malleolus occurs with a sharp, non-physiological rotation of the foot.
Tibia (tibia)
It seems that I have already told you a little reminder that will help you forever stop confusing the names of these bones in Latin. This is related to Muay Thai - I love this sport and have devoted quite a lot of time to it.
One of the most typical strikes in Muay Thai is the low kick, a powerful amplitude strike with the shin to the opponent's thigh. This blow is delivered by the anterior edge of the tibia. So, “t” is “Thai boxing” in which the blow is delivered by the “Tibiya”, that is, the tibia. Remember this “T” and you will never confuse tibia and fibula.
By the way, in this combat sport the lower leg is often raised and used as a shield to protect the torso. In this case, the blows also fall on the hard anterior edge of the tibia.
I can talk about this for a very long time if you don't stop me - but it's time for us to get back to anatomy.
The tibia, like the femur, consists of three parts - the upper and lower ends (also called the epiphyses), and the body that is located between them, which is also called the diaphysis. I highlighted the epiphyses in blue, and the diaphysis in yellow:
Upper end/upper epiphysis (extremitas superior)
At the upper end of the tibia there are large concave areas for articulation with the femur. As we know from the previous lesson, in anatomy such areas are called condyles .
Accordingly, the tibia has medial and lateral condyles (condylus medialis/condylus lateralis). Between these condyles there is a small protrusion called the intercondylar eminence (eminentia intercondylaris). In this picture we see the articulation of the tibia and fibula. I've highlighted the tibial condyles in blue and the intercondylar eminence in yellow:
If we look at the intercondylar eminence from above, we will see that it consists of two tubercles - medial (tuberculum intercondylare mediae) and lateral (tuberculum intercondylare laterale). Anterior to the elevation there is a small area called the anterior intercondylar area (area intercondylaris anterior), and behind there is the same area - the posterior condylar area (area intercondylaris posterior).
These two fields are very important formations, because it is to them that powerful cruciate ligaments are attached, which strengthen the knee joint.
In order to properly examine all of the listed anatomical formations, we need a top view. I identified the following anatomical formations:
- Anterior intercondylar field - red;
- Posterior intercondylar field - green;
- The lateral intercondylar tubercle is yellow;
- The medial intercondylar tubercle is blue.
In general, the condyles and intercondylar eminence form the superior articular surface (facies articularis superior). The upper articular surface of the tibia is connected to the femur. There is also a lower articular surface for connection with the foot, which will be discussed a little later.
Body of the tibia (corpus tibiae)
The body of the tibia has a triangular shape, and, accordingly, three edges and surfaces. If we look at the femur from the front, we see a pointed anterior edge (margo anterior). This is exactly the place that I talked about a little higher when talking about Thai boxing. You can palpate the leading edge on the shin - it is very well palpated through the skin.
As it approaches the upper epiphysis, the anterior edge transforms into a rather large triangular tuberosity, which is called the tibial tuberosity (tuberositas tibiae). This tuberosity is also easily detected by palpation.
Accordingly, the anterior surface is adjacent to the anterior edge - medial (facies medialis) and lateral (facies lateralis). I've highlighted the tibial tuberosity in blue and the anterior edge in yellow:
The lateral edge is directed towards the fibula, more precisely, towards the interosseous space between the tibia and fibula, which is why it is called the interosseous edge (margo interosseus). The medial edge (margo medialis) is directed towards the medial side, it is significantly rounded compared to the anterior and lateral edges.
Here cutting in my favorite horizontal plane will help us a lot. If you have already studied the muscles of the lower leg, you can practice recognizing them, but if not, we can see the tibia from an unusual angle. The number 1 represents our tibia, and we can do some parts.
I've highlighted the anterior edge in green, the interosseous edge in yellow, and the medial edge in blue:
The posterior surface of the tibia (facies posterior) is also of significant interest to us. If we look at the femur from the back, we will see a flat surface, which is crossed by an oblique line in the upper third. This is the line of the soleus muscle (linea musculi solei). You can read about this muscle and other muscles of the back of the leg here. In this picture I have outlined the line of the soleus muscle (back view):
Without my emphasis:
Slightly below and lateral to this line there is a nutritious opening (foramen nutricium), which leads under the periosteum into the Volkmann canals. Feeding vessels and nerves enter the bone through these channels. I won't be able to show this in an illustration, but if you have a quality preparation of the tibia in your hands, you will immediately find this hole.
Lower end/epiphysis of the tibia (extremitas inferior)
The lower epiphysis of the tibia articulates with the foot and the fibula. On the lateral side of the epiphysis there is a small depression called the fibular notch (incisura fibularis). It is in this area that the fibula adjoins the tibia.
The medial part of the lower epiphysis has the appearance of a short pointed protrusion. This is the medial malleolus (malleolus medialis), which, like a fork, covers the talus bone of the foot. Slightly posterior to it is the ankle groove (sulcus malleolaris). If we look at the tibia from below, we see the lower articular surface (facies articularis inferior) for articulation with the talus.
In this drawing I have outlined the medial malleolus in red and the ankle groove in green:
Without color highlighting it looks like this:
Treatment of tibial fractures
Currently, treatment of a tibial fracture is usually performed through surgery. Due to the anatomical structure of the lower leg, the tibia along its main length is located superficially (not covered by muscles along the medial surface), which often leads to secondary perforation of the skin with bone fragments during a fracture. To immobilize fragments of fractures of the tibia, hospitals use skeletal traction on the heel bone. This method is used for preoperative preparation and improvement of the condition of the skin on the injured lower leg.
In our center, traumatologists and orthopedists use the most modern methods of conservative and surgical treatment of tibial fractures. The use of the latest methods of extraosseous and intramedullary osteosynthesis allows us to speed up the recovery and rehabilitation of patients with fractures of the tibia . As a rule, the patient can put weight on the injured leg the next day after surgery. In most cases, the use of osteosynthesis for intra-articular fractures in the early stages allows for the most accurate restoration of the articular surfaces, which eliminates the risk of early development of arthrosis of the damaged joint.
Symptoms
The lower leg is richly innervated and has a lot of pain receptors. They are located not only in muscles, ligaments and tendons, but also in the periosteum (a dense connective tissue membrane covering the entire bone, except the articular surfaces). But they are absent directly from bone tissue. Therefore, a formed cyst can be completely asymptomatic for a long time until its growth leads to swelling of the affected bone and involvement of the periosteum and other anatomical structures in the pathological process.
At the same time, solitary cysts develop more slowly, and therefore are rarely accompanied by pronounced clinical manifestations. Aneurysmal cysts are characterized by rapid growth, which provokes the appearance of characteristic signs:
- discomfort, and then pain in the lower leg, which occurs and intensifies with prolonged standing, walking, physical activity and gradually becomes permanent;
- formation of bone swelling in the area of cystic cavity formation;
- limited mobility in the knee or ankle joint;
- gait changes, lameness;
- swelling, redness of soft tissues, local increase in temperature;
- numbness, tingling sensation in the lower leg or even foot.
The tibia bones are highly durable, but the formation of cystic cavities inside them inevitably makes them more vulnerable and susceptible to pathological fractures, even in the absence of aggressive traumatic factors. In this case, it is the fracture that often becomes the first manifestation of a bone cyst of the tibia or fibula. It can happen not only when receiving a strong blow to the shin or falling, but also as a result of physical stress on the lower limb.
As a result, when an x-ray is performed to diagnose a fracture, a cyst is often discovered, which was the reason for its occurrence. Moreover, after immobilization of the limb and fusion of the bone, in some cases, a decrease in the size of the pathological cavity or even its complete closure is observed. But you should not pin all your hopes on such an outcome, since closure of the cyst does not always occur even after the final consolidation of bone fragments.
In severe cases, deformation of the affected joint or the lower leg itself is observed. This is provoked by the mechanical pressure of the neoplasm and the swollen part of the bone on neighboring anatomical structures and the destruction of the maternal bone itself.