Symptoms of involvement of the tibial nerve

The tibial nerve (n. Tibialis) is formed by the fibers of the LIV-SIII spinal roots. In the distal part of the popliteal fossa from the tibial nerve, the medial cutaneous nerve of the shin extends. It passes between the two gastrocnemius head and perforates the deep fascia in the middle third of the posterior surface of the shin. On the border of the posterior and lower third of the shin, the lateral cutaneous branch of the common peroneal nerve joins this nerve, and from this level it is called the gastrocnemius nerve (n. Suralis).

Next, the nerve passes along the Achilles tendon, giving the branch to the posterior armature of the lower third of the shin. At the level of the ankle, it is located behind the tendons of the peroneal muscles and gives here the outer heel branches to the ankle and the heel. The calf nerve is located superficially on the foot. He gives branches to the ankle and tarsal joints and supplies the skin of the outer edge of the foot and V finger to the level of the final interphalangeal articulation. On the foot, the calf nerve also communicates with the superficial peroneal nerve. The area of innervation of the gastrocnemius depends on the diameter of this anastomosis. It can include a significant part of the rear of the foot and even adjacent surfaces of III and IV interdigital spaces.

Symptoms of the defeat of the gastrocnemius nerve are manifested in the form of pain, paresthesia and sensation of numbness and hypesthesia or anesthesia in the region of the outer edge of the foot and V finger. There is a soreness at the site of the nerve compression during palpation (behind and below the external ankle or on the outer part of the heel, at the outer edge of the foot). Finger compression at this level causes or intensifies painful sensations in the region of the outer edge of the foot.

The initial sections of the tibial nerve are supplied by the following muscles: the triceps muscle of the shin, the long flexor of the fingers, the plantar, popliteal, posterior tibial long flexor of the thumb,

The triceps muscle of the lower leg is formed by the gastrocnemius and soleus muscles. The calf muscle flexes the lower limb in the knee and ankle joints.

Tests to determine the calf muscle strength:

1. the subject, lying in a supine position with a straightened lower limb, is offered to bend her in the ankle joint; the examiner is resisting this movement and palpating the contracted muscle;
2. the subject, lying in the supine position, is suggested to bend the lower extremity in the knee joint at an angle of 15 °; the examiner is resisting this movement.

The flukes muscle flexes the lower limb in the ankle joint.

The test for determining the soleus muscle strength: the examinee, lying in the supine position with a 90 ° bent at the knee joint with a lower limb, is suggested to bend it in the ankle joint; The examiner is resisting this movement and palpating the contracted muscle and tendon.

The plantar muscle with its tendon is weaved into the medial part of the Achilles tendon and participates in flexion in the ankle joint.

The popliteal muscle participates in flexion in the ridge and rotation of the shins inward.

The posterior tibialis muscle leads and raises the inner edge of the foot (supiniruet) and promotes bending in the ankle joint.

The test for determining the strength of the posterior tibial muscle: the subject is in a supine position with a straightened lower limb, bends it in the ankle and simultaneously leads and raises the inner edge of the foot; the examiner is resisting this movement and palpating the contracted muscle and strained tendon.

The long flexor of the fingers bends the nail phalanges of the II-V toes of the foot.

The test for determining the strength of the long flexor of the fingers: the patient in the supine position is offered to bend at the joint distal phalanges of the II-V toes of the foot; The investigator obstructs this movement and holds the proximal phalanges with the other hand with the unbent. The long flexor of the big toe bends the toe of the foot; its function is verified similarly.

From the tibial nerve somewhat above the inner ankle, the inner heel skin branches depart which innervate the skin of the posterior region of the heel region and the back part of the sole. At the level of the ankle, the main trunk of the tibial nerve passes in the rigid osteophyseal tunnel - the tarsal canal. This channel goes obliquely downward and forward, communicating the area of the ankle joint with the sole, and is divided into 2 floors: the upper one - the hip and the lower one - the sub-ankle. The upper floor is bounded from the outside by the osteoarticular wall. From the inside, the upper floor is bounded by an inner annular ligament, formed from the superficial and deep aponeurosis of the shin. The lower floor is bounded from the outside by the inner surface of the calcaneus, from the inside - by the adductor muscle of the thumb, enclosed in the duplication of the inner annular ligament. The tarsal canal has two openings: the upper and lower ones. The tendon of the posterior tibial muscle, the long flexor of the fingers and the long flexor of the thumb, and the posterior tibial vascular-neural bundle pass through the canal. It is located in the fibrous case and includes the tibial nerve and the posterior tibial artery with the satellite veins. In the upper floor of the tarsal canal, the neurovascular bundle passes between the tendons of the long flexor of the thumb. The nerve is located outside and behind the artery and is projected at an equal distance from the calcaneal tendon to the posterior edge of the inner ankle. In the lower level of the canal, the neurovascular bundle is attached to the posterior armature of the tendon of the long flexor of the thumb. Here the tibial nerve is divided into terminal branches - the inner and outer plantar nerves. The first of them innervates the skin of the plantar surface of the inner part of the foot and all the phalanges of the fingers, the back surface of the terminal phalanges I-III and the inner half of the fourth finger, as well as the short flexors of the fingers that fold the middle phalanges of the II-V fingers, the short flexor of the thumb, which leads the thumb of the foot, and I and II wormlike muscles. The external plantar nerve supplies the skin of the external part of the plantar surface of the foot, the plantar surface of all phalanges of the fingers and the back surface of the terminal phalanges V and the outer half of the fourth finger. Motor fibers innervate the square muscle of the sole; flexion is promoted by I-IV interosseous and II-IV wormlike muscles, a muscle that removes the little finger of the foot, and, in part, a short flexor of the little finger of the foot. The skin of the heel area is innervated by the internal calcaneus nerve, which extends slightly from the common trunk of the tibial nerve just above the tarsal canal.

When the common trunk of the tibial nerve is damaged, the paralysis of the muscles develops in the popliteal fossa and the possibility of flexion of the lower extremity in the ankle joint, in the joints of the distal phalanges of the toes, the middle phalanges of the II-V fingers and the proximal phalange of the 1st toe. Because of the antagonistic contraction of the extensor of the foot and the fingers innervated by the peroneal nerve, the foot is in the unbending position (rear flexion); the so-called heel foot (pes calcaneus) develops. When walking, the patient rests on the heel, we can not rise on the toe. Atrophy of the interosseous and vermiform muscles leads to the clawlike position of the toes (main phalanges are bent at the joints, and the middle and terminal ones are bent). It is not possible to remove and bring fingers.

In case of lesion of the tibial nerve, below the branching of the branches to the gastrocnemius muscles and the long flexor of the fingers, only the small muscles of the plantar part of the foot are paralyzed.

For the topical diagnosis of the level of lesion of this nerve, the sensitivity disturbance zone is important. Sensitive branches consistently depart for the innervation of the skin on the posterior surface of the shin (the medial cutaneous nerve of the calyx - in the popliteal fossa), the external surface of the heel (medial and lateral heel branches - in the lower third of the shin and at the level of the ankle), on the outer margin of the foot (lateral rear cutaneous nerve), on the plantar surface of the foot and toes (I - V common plantar digital nerves).

When lesions of the tibial nerve at the level of the ankle and lower sensitive disorders are localized only on the sole.

In the case of a partial lesion of the tibial nerve and its branches, a causal syndrome often occurs. Painful pain extends from the back of the lower leg to the middle of the sole. It is extremely painful to touch the plantar side of the foot, which hinders walking. The patient rests only on the outer edge of the foot and on the fingers, limping when walking. The pain can be irradiated throughout the lower limb and sharply strengthened by lightly touching any part of the skin on this limb. Patients can not walk, even relying on crutches.

Often pains are combined with vasomotor, secretory and trophic disorders. Develops atrophy of the muscles of the back of the lower leg and the interosseous muscles, as a result of which metatarsal bones clearly appear on the rear of the foot. Achilles and plantar reflexes decrease or disappear.

When the terminal branches of the tibial nerve are affected, reflex contractures of the affected limb are sometimes observed with edema, hyperesthesia of the skin, and osteoporosis of the foot bones.

Most often, the tibial nerve is affected in the area of the tarsal canal by the mechanism of tunneling (compression-ischemic) syndrome.

In the syndrome of the thalzal canal, pain comes to the fore. Most often they are felt in the posterior parts of the shin, often in the plantar part of the foot and fingers, rarely radiate to the thigh. Paresthesias are observed on the plantar surface of the foot and fingers. Here, too, there is a feeling of numbness and a decrease in sensitivity within the zone of innervation of the external and / or internal plantar nerve, and sometimes also in the area provided with the heel nerve. Less common sensory disorders are motor - paresis of small muscles of the foot. At the same time, flexion and dilution of the fingers are difficult, and in far-reaching cases, because of muscle atrophy, the foot becomes a clawed paw. The skin becomes dry and thin. In the syndrome of the tarsal canal, light percussion or finger compression in the area between the inner ankle and the Achilles tendon causes paresthesia and pain in the sole of the foot, the latter can be felt in the posterior parts of the shin. The painful sensations are also provoked both in pronation and at the same time formed foot extensity, as well as in the forced plantar flexion of the first finger against the action of the resistance force.

With this tunnel syndrome, sensitive disorders in the calcaneal region are rare. Weak flexion of the lower leg and foot, as well as hypesthesia along the posterior outer surface of the tibia - signs of affection of the tibial nerve above the level of the tarsal canal

[1], [2], [3], [4]