Lower leg
The lower leg ( Latin crus ) is part of the leg and is located between the knee and the foot .
bone
The lower leg is supported by two bone formed, the shinbone ( tibia ) and the fibula ( fibula ). These are connected at the top by a tight joint ( amphiarthrosis ) and at the bottom by a ligament ( syndesmosis tibiofibularis ). A firm, connective tissue structure ( membrana interossea cruris ) runs between them .
Adjacent joints
The joint between the knee and the lower leg ( knee joint ) is a swivel and hinge joint; the joint surfaces are located on the knots of the thighbone ( femur ) and the shinbone as well as on the back of the kneecap (patella).
The joint between the lower leg and foot (upper ankle joint ) is likewise a hinge joint and is by the two ankle on the tibia and fibula, and the talus ( talus formed).
Musculature
The muscles of the lower leg are summarized according to their function and location and divided into four groups as follows:
- The front lower leg muscles are made up of
- the extensors on the anterior ( ventero-lateral ) side and
- the fibula muscles in the area of the fibula on the outer (lateral) side.
- The rear lower leg muscles are made up of
- the superficial flexor muscles ( flexors commonly as) on the back, triceps surae muscle are designated and
- the deep flexors on the back.
| Lower leg muscles | |||
|---|---|---|---|
| anterior lower leg muscles | posterior lower leg muscles | ||
| Straightener | Fibula muscles | superficial layer | deep layer |
| Tibialis anterior muscle | Musculus fibularis longus | Soleus muscle | Tibialis posterior muscle |
| Extensor digitorum longus muscle | Musculus fibularis brevis | Gastrocnemius muscle | Flexor hallucis longus muscle |
| Extensor hallucis longus muscle | Plantaris muscle | Flexor digitorum longus muscle | |
In quadruped mammals , the superficial flexor of the toe of the foot ( flexor digitorum pedis superficialis ) lies between the two heads of the gastrocnemius muscle .
Lodge, fascia, and compartment syndrome
anatomy
The entire lower leg is enclosed by a connective tissue skin, the lower leg fascia ( Fascia cruris ). The individual muscle groups are enclosed and separated from each other by tough and non-stretchable fasciae. The ligament between the two bones and the deep sheet ( lamina profunda ) of the lower leg fascia, which separates the deep and superficial flexors, are also involved in this separation.
The separation of the muscle groups results in so-called muscle boxes (also compartments) in which muscles with related functions are grouped together. Each compartment is separated from neighboring compartments by a surrounding connective tissue and with its contents forms an almost completely self-contained space.
According to the muscle groups, the following boxes can be found in the lower leg:
- the extensor compartment (anterior compartment, sometimes also called the tibialis anterior compartment )
- the peroneal compartment (lateral compartment or fibular compartment )
- the superficial flexor box (superficial rear compartment)
- the deep flexor box (deep rear compartment)
Injuries and illnesses
The fascia around the boxes have the effect of compression and thereby limit swelling . However, after lower leg injuries, bleeding can also occur in a muscle box. The coarse membranes of connective tissue cannot expand, so that the pressure in the box increases significantly. The most important consequence is compression of the neurovascular bundle of the lower leg. This can lead to irreparable damage, particularly to the deep and superficial peroneal nerves. As a result, an equinus develops. This phenomenon is called the compartment syndrome . There is usually no loss of pulse due to pinching of the arteries, as there is a risk of nerve damage from a pressure in the lower leg boxes of 40 mmHg . The normal systemic pressure averages around 100 mmHg, which is why the arteries of the lower leg remain open even in the case of the compartment syndrome. If action is not taken quickly enough, the nerves as well as the muscles die. In the event of a compartment syndrome, action must therefore be taken quickly. The boxes of the lower leg must be opened quickly so that the pressure normalizes. Irreparable damage can u. a. loss of function of the nerves and contractures of the scarred muscle tissue.
Even after a severe overload z. B. In sport, an unfamiliar long-distance run can lead to a compartment syndrome. Even bandages that are too tight can have such an effect.
The symptoms are pain, redness, swelling, loss of function and sensory disturbances. Failure to act quickly enough will cause irreparable damage. Prophylactically, in the event of fractures, the legs should be raised to avoid a compartment syndrome. Damage to the extensor compartment on the front of the leg (tibialis anterior syndrome) is particularly common. Similar problems can also occur in the forearm muscles.
Arteries
In the squat, the popliteal artery divides into the
- Arteria tibialis anterior (anterior tibial artery ), known in animals as the arteria tibialis cranialis , and the
- Arteria tibialis posterior (posterior tibial artery ), known in animals as the arteria tibialis caudalis .
The anterior tibial artery ( arteria recurrens tibialis anterior ), which rises again to the knee, and the inner and outer anterior arteries of the ankle ( arteria malleolaris anterior medialis and arteria malleolaris anterior lateralis ) originate from the anterior tibial artery . Eventually it ends in the artery of the back of the foot ( arteria dorsalis pedis ). The arteria tarsalis medialis and the arteria tarsalis lateralis originate from this. Slightly above the metatarsophalangeal joints, the arteria dorsalis pedis and the arteria tarsalis lateralis form the arteria arcuata . The deep metatarsal arteries ( arteriae metatarsales dorsales ) on the dorsum of the foot , which are lost in the arteriae digitales dorsales , thus supply the toes with blood.
The fibrous artery , the inner plantar artery ( arteria plantaris medialis ) and the outer plantar artery ( plantaris lateralis ) arise from the posterior tibial artery .
Veins
Superficial veins
In the lower leg there is on the one hand the large hidden vein ("large rose vein", also called "large rose vein", great saphenous vein ; medial saphenous vein in animals ), which extends from the foot in front of the inner ankle, then in the middle to the shin and finally behind her central articular knot on the inside of the thigh. The vein opens into the femoral vein (vena femoralis) in the groin region. The small hidden vein ("small rose vein", analogously also called "small rose vein", vena saphena parva ; in animals vena saphena lateralis ) runs behind the outer malleolus, then along the back of the calf in the subcutaneous fatty tissue and finally pours into the knee flexor vein ( vena poplitea ). The small, hidden vein is often used in dogs and cats to draw blood or give intravenous injection .
Deep veins
In the calf (Latin Sura ) a series of deep veins run between the muscles. They are functionally more important than the superficial veins. They usually accompany the arteries and are often created as two or three accompanying vessels around the arteries. They are divided into the following groups according to the arteries:
- Tibialis posterior group
- Tibialis anterior group
- Fibularis group
The veins of the tibialis posterior group in particular are often affected by deep vein thrombosis .
annoy
In the hollow of the knee, the sciatic nerve ( sciatic nerve ) divides into the common fibula nerve ( common peroneal nerve ) and the tibial nerve ( tibial nerve ).
The common fibula nerve divides into the deep fibula nerve ( Nervus peroneus profundus ) and the superficial fibula nerve ( Nervus peroneus superficialis ). The tibial nerve only divides at the foot.
