Knee-joint. Form and movement. Stretching is optimal prevention

Articulatio genus

Knee-joint form: condyles femur, condyles tibia and patella. In half of the cases, the lengths of the femoral condyles are equal; in the second half, the length of the external condyle predominates. The medial condyle in all cases is wider and higher than the external one. The articular platforms of the tibia have the following dimensions: at the medial condyle - length 4.1-5.3 cm, width - 2.8-3.8 cm, at the lateral condyle - length 3.3-4.9 cm, width - 3 .0-4.1 cm. The thickness of the cartilaginous cover at the condyles of the femur in the center is 1.6-6 mm, and gradually decreases towards the periphery. The patella has on average: a length of 3.3-5.3 cm, a width of 3.6-5.5 cm and a thickness of 2-2.8 mm.

Rice. 150. Opened knee joint; front view.

Cavity knee joint is a complex complex of communicating gaps bounded by articulating bones, menisci, joint capsule, synovial membrane-covered intra-articular ligaments and fatty protrusions. The capacity of the joint cavity in adults with a bent knee ranges from 75 to 150 cm3. The maximum capacity of the joint cavity in men is 150 cm3, in women 130 cm3.

The knee joint capsule has an outer fibrous and inner synovial membrane (layers). The synovial membrane is attached to the edges of the menisci and articular cartilages and, adjoining in certain areas to the femur and tibia, to the inner surface of the fibrous layer of the joint capsule, fatty tissue, intra-articular ligaments and the tendon of the quadriceps femoris muscle, forms protrusions in various places - inversions. The fibrous shell of the capsule on the tibia is attached, slightly moving downwards from the articular cartilage and reaching the tibial tuberosity in front; it is firmly fixed to the edges of the patella, above which the capsule is attached to the tendon of the quadriceps femoris muscle, then passes well above the articular cartilage to the anterolateral surfaces of the femur, descends along them, bends around the bottom and then behind the epicondyles and is attached above the condyles along the linea intercondylaris.

The knee joint has nine twists: five in the front and four in the back. The protrusion of the synovial membrane, located above the patella and forming the superior patellar inversion, is limited: in front - by the quadriceps femoris muscle, in the back - by the femur, at the top and partially on the sides - by a fold resulting from the transition of the synovial membrane from the posterior surface of the quadriceps femoris muscle to the anterior surface of the femoral muscle bones. According to data, in 90.5% of cases in the arch of the superior inversion there is a larger or smaller hole through which the inversion communicates with the bursa suprapatellaris, and sometimes forms a joint protrusion rising above the patella by 10-12 cm. The length of the upper inversion is 5-8 cm (on average 6.4 cm), width - 3-10 cm.

From above, from the sides and from behind, the upper turn is surrounded by fiber. M. approaches the synovial membrane of the volvulus from above. articularis genus. The inferolateral sections of the superior inversion pass from the medial side into the anterior superior medial inversion, and from the lateral side into the anterior superior lateral inversion. Both last inversions are located on the sides and above the patella, respectively, in front of the anteromedial and anterolateral surfaces of the femoral condyles and behind the fibrous layer of the joint capsule, covered by mm. vastus medialis and lateralis, as well as retinacula patellae mediale and laterale. On the sides of the articular surfaces of the femur, these inversions descend down to the menisci. The gaps between the menisci and the articular surface of the tibia communicate with the lower inversions, and the gaps between the outer surfaces of the condyles and the joint capsule and between the inner surfaces of the condyles and the cruciate ligaments covered with the synovial membrane communicate with the posterior superior inversions. In this case, the medial condyle-capsular fissure is wider than the lateral one. Most narrow part The condylar-ligamentous cleft is located at the intercondylar eminence of the tibia, and the condylar-ligamentous clefts themselves are smaller and shorter than the condylar-capsular clefts.

Rice. 151. Articular surfaces, menisci and ligaments of the knee joint in a cross section at the level of the joint space (3/4).
Individually expressed folds protrude into the anterior part of the joint cavity on the sides of the patella - plicae alares, from which or from the apex of the patella to the anterior cruciate ligament the plica synovialis infrapatellaris is directed. These folds of the synovial membrane are formed by a protrusion of adipose tissue - corpus adiposum infrapatellare, which is located below the patella and behind the lig. patellae and the fibrous membrane of the joint capsule, separating the bursa infrapatellaris profunda from the joint cavity.

Rice. 152. Ligaments that strengthen the bursa of the knee joint; back view.

Below the medial and lateral menisci, between the joint capsule and the anterior superomedial and superolateral parts of the tibia, the anterior inferior medial and anterior inferior lateral inversions are located, respectively. At the top, both inversions of the gap between the meniscus and the cartilaginous surface of the tibia communicate with common cavity knee joint. The ends of the turns facing towards midline joint, closed and limited in front by the corpus adiposum infrapatellare. The anterior lower medial and lateral inversions each pass on their side into the posterior lower medial and lateral inversions, which, like the anterior ones, are bounded above by the meniscus, in front and on the sides by the tibia, and behind by the joint capsule. The ends of the inversions facing the midline of the joint are closed: at the medial inversion along the inner edge of the posterior cruciate ligament, at the lateral inversion - slightly outward from the lateral edge of the same ligament.

Rice. 153. Opened knee joint; back view.
The length of the ligament along the medial edge is 3.3 cm, along the lateral edge - 2.6 cm. Lig. The cruciatum posterius starts from the outer surface of the medial femoral condyle, goes down and slightly back and, crossing with the anterior cruciate ligament, attaches to the area intercondylaris posterior and to the posterior edge of the upper articular surface of the tibia. The length of the ligament along the lateral edge is 3.9 cm, along the medial edge - 2.9 cm.

Rice. 154. Opened knee joint; view from the medial side.

Rice. 155. Opened knee joint; view from the lateral side.

The joint is strengthened in front by lig. patellae, running from the patella to the tibial tuberosity. In front and medially - retinaculum patellae mediale, consisting of transverse fibers running from the medial epicondyle to the patella, and longitudinal fibers. The retinaculum patellae laterale is located anteriorly and laterally, the transverse fibers of which go from the lateral epicondyle to the patella, and the longitudinal fibers from the patella to the anterolateral edge of the tibia and to the tractus iliotibialis. On the lateral side the joint is strengthened by lig. collateral fibulare. The fibular collateral ligament originates from the lateral epicondyle of the femur and is attached to the head of the fibula in the form of a flat-rounded cord. The length of the ligament is 4-7 cm, thickness - 2-8 cm. The ligament runs isolated from the articular capsule. Below, at the head of the fibula, it is covered by a sheath or simply adjacent to it behind or outside the tendon of the biceps femoris muscle. On the medial side, the capsule of the knee joint is strengthened by lig. collateral tibiale. It starts from the medial epicondyle of the femur and attaches to the medial surface of the tibia. The length of the ligament is 7.1-12.5 cm, width - 5-15 mm. In almost half of the cases, the ligament has the appearance of a wide limited strip, sometimes (22%) only the anterior part of the ligament is developed, sometimes (13%) the entire ligament is insufficiently developed. At the back, the articular bursa of the knee joint is strengthened by the oblique popliteal ligament, which is isolated from the outside but intimately connected to the bursa. Lig. popliteum obliquum runs from the posteromedial edge of the tibia to the lateral condyle of the femur; most often well expressed. The ligament is a continuation of the lateral bundle of the semimembranosus tendon. Another ligament is lig. popliteum arcuatum - arcuately covers the posterior superolateral part of the popliteus muscle and is part of its fibrous sheath. The knee joint is spherical in shape, and block-rotatory in function.

Rice. 156. Sagittal section of the knee joint.

The blood supply to the knee joint comes from the rete articulare genus. From the arterial network of the knee joint, networks of the synovial membrane are formed, located in the subsynovial layer and in the thickness of the synovial membrane. The menisci are supplied with blood vessels from the adjacent sections of the synovial membrane, from the middle and lower medial and lateral arteries of the knee. The cruciate ligaments are supplied with blood by the middle artery of the knee, which near the ligaments is divided into ascending and descending branches that supply not only the ligaments, but also the epiphyses of the femur and tibia, tissue, synovial membrane, and menisci. The descending branch of the anterior cruciate ligament forms a permanent anastomosis with branches penetrating the plica synovialis infrapatellaris from the inferior arteries of the knee and the anterior tibial recurrent artery.

Rice. 157. Frontal cut of the knee joint.

Veins from all parts of the knee joint originate from capillary networks. Small veins run independently of the arteries, while large veins accompany the arteries one or two at a time. The small veins of the condyles of the femur are united into a single plexus, from which larger veins are formed that extend to the surface of the bone along the lateral surfaces of the condyles above the facies patellaris, in the area of ​​the intercondylar fossa and in the lower part of the popliteal surface. In the condyles of the tibia, the intraosseous veins are located in the frontal plane perpendicular to the long axis of the diaphysis and with 8-10 trunks they reach the surface of the bone in the area of ​​the lateral surfaces of the condyles.

Lymph from the knee joint flows through the lymphatic vessels accompanying blood vessels. From the superomedial part of the knee joint bursa lymphatic vessels along the way a. genus descendens and a. femoralis go to the deep inguinal lymph nodes. From the area of ​​branching of the superior and inferior medial and lateral arteries of the knee and the anterior tibial recurrent artery, lymph flows into the popliteal lymph nodes. From the posterior sections of the joint capsule, from the cruciate ligaments, lymph flows into lymph node, located on the capsule, most often near a. genus media.

Numerous branches of the femoral, obturator and sciatic nerves approach the knee joint. The capsule and ligaments of the anterior surface of the joint are innervated by: I) in the area of ​​the medial quadrants - branches from rr. cutanei anteriores and the musculocutaneous branch of the femoral nerve (sometimes very large - from 0.47 to 1.2 mm in diameter), descending down m. vastus medialis and dividing into 3-5 branches. Sometimes smaller branches from this branch penetrate into the anterior inferolateral quadrant; 2) stems of the muscular branch innervating m. vastus medialis; 3) g. infrapatellaris from n. saphenus innervates the inferomedial and inferolateral quadrants of the joint capsule. The branches of M. infrapatellaris can also penetrate into the upper quadrants of the capsule. Branches of the obturator nerve, which are part of n. saphenus, innervate more often the superomedial and less often the superolateral quadrants of the capsule; 4) the capsule and ligaments of the superior lateral quadrant are innervated by branches from the muscular branch to m. vastus lateralis from the femoral nerve and branch sciatic nerve, emerging from under the biceps femoris muscle above the lateral epicondyle of the femur; 5) the inferolateral quadrant of the anterior surface of the joint is also innervated by the branches of n. peroneus communis, extending in the region of the head of the fibula, and the branches of n. peroneus profundus, accompanying the branches of a. recurrens tibialis anterior.

The posterior surface of the joint capsule is innervated by: 1) lateral quadrants - branches of the sciatic nerve, extending 6-8 cm above the level of division of the sciatic nerve with its low division, and from the tibial nerve - with high division. The branches are located lateral to the vascular bundle. From the common peroneal nerve in the region of the head of the fibula, branches begin that return back and innervate the joint capsule in its lower parts. Branches to the joint can also extend from muscle branches to the short head of the biceps femoris muscle; 2) the medial quadrants of the capsule are innervated by the branches of the tibial nerve and the posterior branch of the obturator nerve, emerging from the adductor magnus muscle and reaching the joint capsule along its posterior surface.

The most developed intraorgan nervous apparatus present in retinaculum patellae mediale, lig. collaterale tibiale and in the area of ​​the medial surface of the knee joint capsule. In the fibrous and synovial membranes of the capsule there is a single nerve plexus. Nerves enter the menisci from the side of the synovium and, to a lesser extent, from the side of the cruciate ligaments. In ligaments, nerve elements are localized mainly in the peritenonium and endotenonium. The interconnected nerves of the ligaments, menisci and capsule form the complete nervous system of the knee joint.

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Like the clinical examination, the arthroscopic examination should follow a specific pattern. Only compliance with the rules of systematic examination will guarantee that no pathological changes in any part of the joint will be missed (Table 1).

Table 1

Sequence of arthroscopic diagnosis of the knee joint

In addition, it is necessary to know the basic positions of the joint in space, in which its various parts are most accessible to inspection, and to learn how to maintain these positions during manipulation of the arthroscope and instruments.

After inserting the arthroscope into the joint, its end is in the superior inversion. By placing the light guide from below, and slowly moving the arthroscope back (pushing it out of the joint), the surgeon should see the articular surface of the patella, which will be on top if observation is carried out directly through the eyepiece. When using a video camera, it is necessary to orient it in relation to the arthroscope so that the shiny white surface of the patella occupies the top position on the monitor screen. From this point, the arthroscopic examination begins, with the knee joint fully extended and the patient's foot resting on the surgeon's abdomen (Fig. 1) or supported by an assistant (first position).

Rice. 1. First position of the knee joint to examine the patella and superior inversion: full extension (Kohn D., 1991)

From this position, the surgeon, with careful movements, pushing the arthroscope back and forward, rotating it around its axis to increase the viewing area, examines articular surface of the patella and the patellar surface of the thigh (photo 1). The surgeon can examine the entire surface of the patella by moving it with his free hand in relation to the arthroscope. Normal hyaline articular cartilage looks smooth, white and shiny. Surface layer it is smooth and, when felt with a hook, quite hard and elastic.

Photo 1. Articular surface of the patella

It is well known that pathological changes in cartilage are very difficult to diagnose clinically and radiologically, especially in the early stages. In these cases, arthroscopy may be helpful in assessing the size and location of cartilaginous lesions. The most widely recognized is the 4-degree classification of chondromalacia (Outerbridge R.E., 1961).

I degree - softening, swelling or loosening of the surface layer of cartilage. When pressed with a hook, a hole is formed on the surface (photo 2).

II degree - fiberization of the cartilage with cracks, flaps, erosions that do not reach the deep layers and subchondral bone (photo 3).

III degree - fiberization of the cartilage with deep cracks, flaps, erosions reaching the deep layers and subchondral bone (photo 4).

IV degree - erosions and cartilage defects with exposure of the subchondral bone (photo 5).

Photo 2. Chondromalacia of the patella I degree: softening of the cartilage surface

Photo 3. Chondramation of the patella II degree: superficial fiber disintegration, uneven surface of the cartilage

Photo 4. Chondramation of the medial facet of the patella of the III degree: deep fiber separation, cracks, cartilage flaps

Photo 5. Chondromalacia of the medial femoral condyle, grade III (coarse deep fibering and surface erosion) and tibial condyle, grade IV (subchondral bone plate exposed)

Pathological changes in cartilage are most often observed on the medial facet and in the region of the apex of the patella. Chondromalacia of the patella is often found even in patients who have no complaints of pain behind the patella. Almost all people over 50 years of age can have changes in the patellar cartilage of varying degrees. Therefore, in order to make a judgment about the pathological significance of chondromalacia of the patella detected during arthroscopy, it is necessary to correlate the obtained morphological data with the patient’s complaints (the presence of the so-called femoral-patellar pain syndrome).

Next, the surgeon moves the arthroscope slightly forward and examines structures of the superior patellar inversion. Before entering the superior suprapatellar bursa, the surgeon usually encounters remnants suprapatellar septum, representing either a synovial membrane with a rather large window in the center, or a vertical synovial fold of a crescent shape with a base localized on the medial capsule ( medial suprapatellar fold). Intra-articular bodies may be hidden behind the fold.

The lateral portion of the membrane may be separated from the capsule and look like lateral vertical suprapatellar chord. Sometimes the suprapatellar septum is represented by a complete synovial fibrous membrane (solid or with a narrow slit-like opening) and separates the suprapatellar bursa from the main cavity of the joint (photo 6). To ensure that the arthroscope is actually inserted into the bursa, the surgeon must find on the anterior wall of the superior patellar inversion the longitudinal fibers of the quadriceps tendon and the articular muscle of the knee, which is attached to the superior vault of the capsule, visible through the synovium (Figure 7). If the muscles are not visible, then it is most likely that the end of the arthroscope is in front of the continuous suprapatellar septum.

Photo 6. Suprapatellar septum with a large window (entrance) into the suprapatellar bursa (a); medial suprapatellar fold (b); vertical lateral suprapatellar chord (c). Complete suprapatellar membrane: an irrigation cannula inserted into the bursa is visible through the septum (d)

Photo 7. Longitudinal strands of fibers of the quadriceps femoris tendon under the synovial membrane of the anterior wall and the articular muscle of the knee at the apex of the suprapatellar bursa

Complete suprapatellar septum is a rudiment of the embryonic membrane and in some cases can be the cause of femoral-patellar pain syndrome. It impedes the circulation of synovial fluid between the joint cavity and the suprapatellar bursa, contributing to a chronic increase in pressure in the bursa and the development (after acute or chronic injury) of isolated synovitis or bursitis. With forced movements in the joint, a dense fibrous membrane can be pinched between the extensor apparatus and the patellar surface of the femur, causing mechanical local synovitis and chondromalacia of the contact zone of the patella. In such cases, arthroscopic membrane resection is an effective treatment method.

In the superior patellar inversion, the subject of study is synovial membrane, which is most pronounced here and more often undergoes pathological changes. When examining, pay attention to color, swelling, vascular pattern and pathological inclusions on the surface and in its layers, to the number, shape, size and structure of synovial villi. The normal synovial membrane is usually pink, smooth and transparent, with a distinct, faint pattern of fine vasculature (Figure 8). On the lower wall of the inversion (the anterior surface of the femur) you can find small thin transparent thread-like villi containing central blood vessels. Some villi may normally have yellowish tint, conditioned high content fat

Photo 8. Normal synovium of the superior inversion

In the acute period of injury to the knee joint, the synovium looks swollen, hyperemic, with an expanded bright vascular network (photo 9). In acute reactive synovitis there is pronounced edema, bright or stagnant hyperemia of the synovial membrane, proliferation and hypertrophy of its filamentous villi (photo 10). Chronic synovitis is characterized by congestive hyperemia, hyperplasia, sclerosis and loss of transparency of the synovial tissue. Overgrown villi acquire a club-shaped shape and an uneven reddish-violet matte color; their vascular pattern cannot be traced (photo 11).

The largest articular bursa in the knee is the patellar bursa. It is located above the upper pole of the patella and is called the superior inversion. The patellar bursa performs an important function - it helps absorb shocks and other impacts on the knee.

Any changes or pathological processes inside the joint cause effusion (accumulation of synovial fluid) in the superior inversion, causing its expansion. If there is an inflammatory process in the patellar bursa, fluid accumulates inside the knee - exudate, mixed with blood and pathogenic microorganisms.

Today we will talk about suprapatellar bursitis - the most common reason, due to which the superior inversion of the knee joint is widened, we will consider and discuss the treatment of this disease.

Suprapatellar bursitis - causes

The human knee is a biomechanical system that has a complex structure. The knee joint consists of many anatomical components that facilitate movement. It bears the maximum load during the day, it is often exposed to injury and various inflammatory processes.

Suprapatellar bursitis is an inflammatory process in the patellar bursa, which develops as a result of injury, infection, excessive loads on the knee. Inflammation can be caused by anything, even minor injury knee joint, minor damage to the kneecap.

The risk of developing pathology increases significantly if the patient has metabolic disorders, obesity, arthritis, or arthrosis. These diseases can provoke the development of a reactive form of suprapatellar bursitis.

This disease may also have chronic course. In this case, it is caused by the deposition of calcium salts in the joint. Accumulating, they violate it motor functions, cause inflammation.

Suprapatellar bursitis - symptoms and signs of the disease

A characteristic symptom of the upper localization of inflammation is the presence of a soft elastic swelling, up to 12 cm in diameter, located in the periarticular area, strictly along the upper part of the knee.

TO common features bursitis include: weakness, decreased performance, painful sensations knee area, its limited mobility. The temperature may rise.

Suprapatellar bursitis - treatment

After examination and diagnosis of “suprapatellar bursitis”, the patient is prescribed necessary treatment. It includes the use of medications, in particular oral NSAIDs - Ketoprofen, Diclofenac, as well as Indomethacin, etc.

Physiotherapy methods are used to eliminate accumulated exudate. If necessary, prescribe surgery.

In mild cases, use external agents that have an analgesic and anti-inflammatory effect: Deep Relief or Nise gel, or chloroform liniment.

In the presence of purulent infection, the patient is prescribed a course of antibiotics. Most often - broad-spectrum drugs.

Most effective way Elimination of exudate accumulated in the knee joint is surgical drainage, in which liquid is pumped out from the bursa (superior inversion) using a special needle. After removing the fluid, an antibiotic solution or anesthetic drug is injected into the cleaned cavity.

In particular severe cases, When conservative methods treatments for inflammation do not bring any effect, and the disease only progresses, surgery to remove the bursa.

For the entire period of treatment, the patient is recommended to limit physical activity in order to give rest to the sore joint. To do this, the knee area is tightly bandaged or special splints are used. To reduce the load on the knee, the patient should move with a cane or use a crutch (depending on the severity of the inflammation).

Superior inversion of the knee joint - treatment with folk remedies

For acute forms of the disease, you can use the following recipe: combine 2 parts together natural honey, 3 parts vodka and 1 part freshly squeezed agave (aloe) juice. Make compresses from the resulting mixture on the sore knee until the condition improves.

At chronic form try this remedy: add 1 tsp of dark laundry soap. Mix with the same amount of honey and melt in a water bath. Mix the warm mixture with 1 tbsp of grated fresh onion. Place it on your knee, wrap it in plastic, and bandage it tightly. Leave it overnight. Treatment – ​​two weeks.

Before using these recipes, be sure to consult your doctor.

Remember that the prevention of acute suprapatellar bursitis is the prevention of any knee injuries. In addition, any inflammatory processes in the body should be treated promptly. To prevent the deposition of calcium salts in the joint cavity, follow a certain diet and drink freshly squeezed juices.

As we said at the very beginning, any changes or pathological processes occurring in the knee joint can cause inflammation of the patellar bursa. Therefore, there can be many reasons why the upper turn is widened. For proper treatment an accurate diagnosis is needed. It will be installed by a doctor after diagnostic procedures.

Well, I’m off to write a sequel about such a condition as gallbladder volvulus. See you on the pages of the site!

The inversions of the synovial membrane represent a series of protrusions, there are nine of them (V.K. Lyamina, 1953), of which three are of the greatest size and importance: one anterosuperior median and two posterior lateral.

The superior inversion is located on the front surface of the thigh above the patella; its anterior side lines the posterior surface of the quadriceps tendon, and its posterior side covers a thick layer located in lower section femur.

Its upper border forms a dome 3–4 cm above the patella, and when communicating with the suprapatellar mucous bursa (which is observed in 85% of people), it rises up the thigh by 10–12 cm.

Posterior inversions are formed when the synovial membrane passes from the back of the femoral condyles to the tibia condyles, but since the synovial membrane simultaneously covers the upper and lower surfaces of the menisci, there are actually not two posterior ones (lateral and medial), but four - two upper posterior more voluminous ones and two infero-posterior inversions.

In addition, two more pairs of anterolateral inversions are distinguished: the upper ones - during the transition of the synovial membrane from the anterior surface of the femoral condyle to the meniscus and the lower ones - during the transition from the meniscus to the tibia.

The anterosuperior inversion (median) communicates with the anterolateral upper inversions, and, in addition, all anterolateral inversions - upper and lower - communicate with the posterior inversions of the same name. In rare cases, the posteroinferior lateral inversion communicates with the tibis-fibular joint.

In addition to the inversions, the synovial membrane forms several folds containing a large amount of fat, which protrude into the articular cavity, creating irregularities between the articular ends of the bones in the form of cushions. These include, first of all, the extensive wing-shaped folds (plicae alares), converging at an angle at the lower edge of the patella (see the figure below).

a - midline incision through the patella; articular cavity divided horizontally by the pterygoid fold and meniscus; anterosuperior and posterior inversions; b - incision through the internal condyle of the femur; the articular cavity is divided by the edge of the pterygoid fold; attachment of the posterior cruciate ligament (drawing from the specimen).

They, in the form of fatty lumps, fill the gap between the front edge of the shin and own connection patella; from the junction of both halves of the fold, protruding deeply into the joint, there is a thin connective tissue bundle (plica synovialis patellaris), which is directed into the depth of the intercondylar fossa of the femoral epiphysis and is attached in front of the cruciate ligament (see figure below).

The infrapatellar fat pad is partially prepared and pulled upward. Pterygoid folds and synovial patellar ligament, attached to the medial side of the lateral condyle. Cruciate ligaments (drawing from the specimen). In the frame at the top left is the knee joint, opened with outside. Covering cartilage of the femur with the vessels feeding it. In front are the pterygoid and patellar ligaments.

The infrapatellar fold, which has a special blood supply and innervation system, becomes of great importance in the function of the joint and in its pathology.

Another fatty accumulation in the form of a flat lining is located above the patella - suprapatellar, under the synovial membrane of the superior inversion. The third fatty accumulation fills the popliteal fossa outside the fibrous capsule and surrounds the groups of vessels and nerves located here.

In addition to large folds, the synovial membrane has small and numerous villi, the number of which is directly dependent on the functional load of the joint (I. P. Kallistov, 1951); in young children the number of villi is insignificant.

The histological structure of folds and villi differs from the structure of the synovial membrane by the presence of a richer network of capillaries or special vascular glomeruli (T. G. Oganesyan, 1952).

“Clinic and treatment of osteoarticular tuberculosis”,
P.G.Kornev

Densely and hermetically enclosed in joint capsule, otherwise it is called articular capsule which is attached to the bones.

Articular capsule (capsule) of the knee joint

The joint capsule protects the joint from injury and damage, from mechanical stress and rupture.

The outside of the joint capsule is lined fibrous membrane, and with inside synovial membrane.

Fibrous membrane It is characterized by high density and strength. It is formed from dense fibrous connective tissue.

Synovial membrane produces synovial fluid (synovium) from the villi located on it. Synovia plays a very important role in the functioning of the joint.

The synovial membrane is very sensitive to traumatic, thermal, chemical influences and to infections, therefore, during various manipulations with the knee, it is necessary to comply with antiseptic requirements. All manipulations should be carried out only experienced doctor(surgeon or orthopedic traumatologist) in conditions of absolute sterility, knowing all the rules and techniques for introducing needles or other instruments into the joint.

Synovial fluid (synovium)- a thick elastic mucus-like mass that fills the cavity of the joints. Normally transparent or slightly yellowish. Performs the function of intra-articular lubrication, preventing friction of articular surfaces and their wear. Participates in maintaining the normal ratio of articular surfaces in the joint cavity, increases their mobility; provides nutrition to articular cartilage, menisci, tendon sheaths and removal of decay products from the joint cavity; serves as an additional shock absorber. The fluid is produced by the synovium of the joint and fills its cavity. ( Wikipedia)

Synovial fluid its composition is close to blood plasma, enriched with various substances ( protein-polysaccharide components), synthesized by the synovial membrane. But synovia differs significantly from blood plasma in a number of parameters (for example, protein in synovia is 3 times less than in blood). The joint fluid should not contain blood and should not be cloudy.

In normal healthy joint liquid contained in small quantities(2.5 - 4 ml in the knee joint). It's quite a bit. IN normal conditions intra-articular pressure is maintained at rest at a level slightly below atmospheric. During movements, a decrease in hydrostatic pressure may be observed. Due to its high specific gravity, synovial fluid accumulates within bursa and does not leave her. Negative pressure in the knee joint promotes the exchange of fluid with the synovial membrane, thus nourishing the articular cartilage.

Protein-polysaccharide The component of synovial fluid is represented by a polysaccharide from the group of glycosaminoglycans - hyaluronan. Gialuronan(better known as hyaluronic acid) is the main element providing the visco-elastic and protective properties of synovial fluid. The villi of the synovial membrane, producing fluid, also produce hyaluronan, as one of the important components. The volume of synovial fluid mainly depends on the amount of hyaluronan, because One of the main functions of this glycosaminoglycan is currently considered to be water retention. Hyaluronan also retains molecules various substances in the joint cavity, limiting the release of fluid from the joint capsule.

Hyaluronic acid (sodium hyaluronate, hyaluronan)- glycosaminoglycan, which is part of connective, epithelial and nervous tissues. It is one of the main components of extracellular substance and is found in many biological fluids (saliva, synovial fluid, etc.) (Wikipedia).

Molecular structure hyaluronic acid It’s quite simple, but this substance plays a huge role in the life processes of our body. Hyaluronic acid takes part in the interaction of cells with extracellular substance, which directly affects wound healing, tissue regeneration and the elimination of inflammation. Hyaluronic acid is also part of the cells. They are the ones who deal with the restoration of cartilage tissue and the production of the necessary compounds and substances for the restoration of cartilage.

Hyaluronan, like other components of the extracellular substance, is constantly renewed in our body. Consequently, the body must constantly maintain a balance between the formation and breakdown of this glycosaminoglycan.

It is now believed that the loss of cartilage tissue is closely related to a lack of hyaluronic acid, which leads to osteoarthritis and other disorders.

Osteoarthritis(synonyms: deforming osteoarthritis (DOA), arthrosis, deforming arthrosis) is a degenerative-dystrophic disease of the joints, the cause of which is damage to the cartilage tissue of the articular surfaces, in which pathological process Not only the articular cartilage is involved, but the entire joint, including bones, ligaments, capsule, synovium and muscles.( Medical Wikipedia)

Hyaluronan is directly involved in the formation of molecules that are located inside cartilage and provide its firmness and elasticity. The same applies to other tissues of our body. Now I think it’s clear why hyaluronic acid is included in all conceivable and inconceivable cosmetical tools(creams, lotions, etc.), why they drink it, eat it, smear it and inject it into the skin. That's right, to strengthen and give elasticity to collagen fibers. How effective this is and whether it achieves its goal is another question. All this depends on the quality of the acid itself, its production, its shape, the size of the molecule, etc. Hyaluronic acid is simple in structure, so the body does not care how it is obtained: produced by the body itself, or from the outside. Based on this fact, a huge number of products and additives with this acid are created.

As I already said, this substance is produced independently in our body, but, unfortunately, with age this process slows down and there is less hyaluronan. The body begins to experience a lack of it.

For various reasons, including our bad habits, poor-quality nutrition and poor lifestyle, “failures” in the synthesis of hyaluronan begin to occur. All this leads to the fact that the cartilage cannot effectively withstand loads, in addition, the lubricating properties of the synovial fluid are reduced.

Synovial fluid normally contains numerous decay products formed during the life of cells of the synovial membrane and cartilage, which enter the joint cavity and undergo lysis (resorption).

The joint fluid also contains various salt crystals and bacteria. The composition of the synovium is constantly changing. At the slightest deviation from the norm, the number and condition of cells, chemical and physical properties synovial fluid.

When a joint becomes inflamed, there is a sharp increase in the amount of protein in the synovial fluid. The body, for example, during an injury, dilates blood vessels and begins to supply blood to this place for recovery. Increased vascular permeability facilitates the passage of proteins into the joint. At the same time, the permeability to water and molecules of other components of the synovial fluid does not change during inflammation. Thus, the amount of protein increases, and an adequate increase in the amount nutrients and the rate of removal of decomposition products does not occur. The composition of the liquid changes and it does not do its job direct use to protect and nourish the joint.

The mechanism of cartilage nutrition is simple. When loaded, fluid is released from the deep layers of cartilage through the pores and spaces between the fibers to lubricate it. When the load decreases, the fluid flows back into the cartilage. Therefore, articular cartilage glides almost without friction, even under significant physical exertion. And the joint fluid constantly circulates in the joint, carrying new nutrients and carrying away decay products. The synovial membrane constantly secretes a new nutritious portion of fluid, it circulates through the joint, lubricating and nourishing it, and is replaced with a new one, taking away everything unnecessary and waste, also passing through the joint capsule and entering the lymphatic channels of our body, and from there out. Lymph, like blood, must circulate constantly and unhindered, removing excess from the body. If stagnation occurs due to injury, spasm or any other reason, swelling of the legs immediately begins, and the likelihood increases. If at this moment there is some kind of infection (fungus, bacteria, virus) in this place, and this cannot be avoided - all this is constantly in our body, then its rapid multiplication will begin, followed by inflammation and even greater swelling of the knee. This is one of the causes of diseases and inflammation in the joint.

And here I will remind you again: only physical exercise and in sufficient quantities they will not allow lymph and blood to stagnate, allowing your internal fluids to circulate freely, bringing good things to your cells and taking away all the bad things. And all this should be a constant, ongoing process that you must maintain throughout your life.

Lack of water and nutrients is one of the main reasons for the lack and deterioration of the quality of synovial fluid.

A lack of synovial fluid impairs gliding and causes crunching in the joint. There are situations when synovial fluid is secreted in sufficient quantities, but its quality suffers as a result of a lack of certain constituent elements, For example .

Glucosamine- a substance produced by the cartilage tissue of joints, is a component of chondroitin and is part of the synovial fluid. As the manufacturers of these drugs assure, the substance increases permeability joint capsule, restores enzymatic processes in the cells of the synovial membrane and articular cartilage. Promotes fixation in the process of chondroitinsulfuric acid synthesis, facilitates normal deposition in bone tissue, inhibits the development of degenerative processes in joints, restores their function, reducing joint pain. (Wikipedia)

Chondroitin- polymeric sulfated glycosaminoglycans. They are specific components of cartilage. Produced by the cartilage tissue of joints, they are part of the synovial fluid. A necessary building component of chondroitin sulfate is glucosamine; with a lack of glucosamine in the synovial fluid, a deficiency of chondroitin sulfate is formed, which worsens the quality of the synovial fluid and can cause crunching in the joints. Chondroitin sulfate has a tropism for cartilage tissue, initiates the process of sulfur fixation during the synthesis of chondroitinsulfuric acid, which, in turn, promotes the deposition of calcium in the bones. Stimulates the synthesis of hyaluronic acid, strengthening connective tissue structures: cartilage, tendons, ligaments. It has an analgesic and anti-inflammatory effect, is a chondroprotector, and promotes active regeneration of cartilage. ( Wikipedia)

Various disturbances in the process of synovial fluid synthesis directly lead to various lesions joints, which ultimately leads to various diseases and destruction. Violation of the correct synthesis of fluid and its composition, unfortunately, very easily occurs with injuries, inflammation, hypothermia, etc. During inflammation, due to increased vascular permeability, the amount of protein in the joint fluid increases. The liquid may become cloudy, and the number of leukocytes in it increases. This disruption of the biochemical processes in the joint causes the appearance of highly toxic substances, which further enhance the inflammatory process, which negatively affects cartilage and its nutrition.

When analyzing synovial fluid, which easily changes its properties, composition, presence and ratio of cells, it is easy to establish the presence and absence of diseases and the stages of diseases. Therefore, when serious illnesses joints, to establish accurate diagnosis, held puncture(sampling) of fluid from a diseased joint with its subsequent laboratory research, including culture to determine the presence of viruses and bacteria.

From all of the above, one can make one very important conclusion: in the joint under the influence various reasons(internal and external) processes of destruction and restoration constantly occur.

Our task is to maintain a balance between factors that damage articular cartilage and factors that promote its protection and regeneration. Accordingly, the disease begins when there is a preponderance towards destruction factors.

That's all. Next time we will talk about those associated with disturbances in the functioning of the joint capsule, synovial membrane and synovial fluid.

All the best, don't get sick!