They represent pathological conditions where peripheral nerves of the upper limbs are compressed in non-stretchable bone-connective and muscle-connective channels through which they pass. A pressure increase in these channels leads to nerve damage and strong pain. Numerous reasons cause compressive neuropathies and they can be anatomic, postural, developmental, inflammatory, traumatic and metabolic nature. The symptoms occurring can be various, from transitory paresthesias to complete damage of neural function.
N. Medianus compressions
1. Carpal tunnel syndrome
The carpal tunnel syndrome occurs at pressuring the n. medianus in the carpal tunnel. The smallest increase of tissue mass from a particular reason can cause compression and nerve ischaemia. It is more frequent in women in menopause, pregnancy, suffering from rheumathoid arthritis. The symptoms occurring as a consequence of compression of this nerve are pain, paresthesias and hypoesthesias in the region of the first three fingers.
The carpal tunnel syndrome is treated surgically. In the local anaesthesia, through the wrist level incision, the flexor retinaculum of the wrist is cut which liberates the nerve from the pressure and the symptoms retreat. The operation lasts about 30 minutes, the hospital is abandoned the very same day, the sutures are removed after ten days.
2. Pronator teres syndrome (PTS)
In this syndrome, compression of the n. medianus occurs at the level of m. pronator teres i.e. at the elbow level. The symtoms characterizing it are the pain on the flexor side of the lower arm, sensor deficit of the thumb and the first three fingers, total and partial loss of flexion of the proximal interfalangeal thumb joint. The symptoms get stronger with physical activity. A surgical therapy includes the nerve decompression at the level of the muscle pronator teres. The elbow is immobilised in mildly bent position for a week, after which starts the physiotherapy.
3. Front interoseal syndrome, compression of the n. medianus-n. interosseus branch
The syndrome is characterised by mild, deep pain in the lower arm which is impaired with physical activity, and vanishes in rest. Sensor incident in the fingers can be absent, and the main characteristic is weakness of the muscle flexor of the thumb and index finger (m. flexor pollicis longus and m. flexor profundus indicis). The treatment is surgical, it implies liberation of the nerve from compression. A function improvement occurs already in the first two to three months.