Motor Phenomena.—­There is immediate and complete loss of voluntary power in the muscles supplied by the divided nerve.  The muscles rapidly waste, and within from three to five days, they cease to react to the faradic current.  When tested with the galvanic current, it is found that a stronger current must be used to call forth contraction than in a healthy muscle, and the contraction appears first at the closing of the circuit when the anode is used as the testing electrode.  The loss of excitability to the interrupted current, and the specific alteration in the type of contraction with the constant current, is known as the reaction of degeneration.  After a few weeks all electric excitability is lost.  The paralysed muscles undergo fatty degeneration, which attains its maximum three or four months after the division of the nerve.  Further changes may take place, and result in the transformation of the muscle into fibrous tissue, which by undergoing shortening may cause deformity known as paralytic contracture.

Vaso-motor Phenomena.—­In the majority of cases there is an initial rise in the temperature of the part (2 to 3 F.), with redness and increased vascularity.  This is followed by a fall in the local temperature, which may amount to 8 or 10 F., the parts becoming pale and cold.  Sometimes the hyperaemia resulting from vaso-motor paralysis is more persistent, and is associated with swelling of the parts from oedema—­the so-called angio-neurotic oedema.  The vascularity varies with external influences, and in cold weather the parts present a bluish appearance.

Trophic Phenomena.—­Owing to the disappearance of the subcutaneous fat, the skin is smooth and thin, and may be abnormally dry.  The hair is harsh, dry, and easily shed.  The nails become brittle and furrowed, or thick and curved, and the ends of the fingers become club-shaped.  Skin eruptions, especially in the form of blisters, occur, or there may be actual ulcers of the skin, especially in winter.  In aggravated cases the tips of the fingers disappear from progressive ulceration, and in the sole of the foot a perforating ulcer may develop.  Arthropathies are occasionally met with, the joints becoming the seat of a painless effusion or hydrops, which is followed by fibrous thickening of the capsular and other ligaments, and terminates in stiffness and fibrous ankylosis.  In this way the fingers are seriously crippled and deformed.

#Treatment of Divided Nerves.#—­The treatment consists in approximating the divided ends of the nerve and placing them under the most favourable conditions for repair, and this should be done at the earliest possible opportunity. (Op.  Surg., pp. 45, 46.)

#Primary Suture.#—­The reunion of a recently divided nerve is spoken of as primary suture, and for its success asepsis is essential.  As the suturing of the ends of the nerve is extremely painful, an anaesthetic is required.