Neuralgia refers to a sharp pain occurring along the course of a nerve. This diagnostic code refers to the internal popliteal nerve which is a sensory and motor nerve innervating the muscles on the posterior surface of the leg and the plantar muscles. Sensations are transmitted from the entire sole of the foot, the back and lower part to the middle third of the leg, to the outer dorsal surface of the foot, and to the terminal phalanges of the toes.

Neuralgia may be caused by pressure on the nerve trunks, faulty nerve nutrition, toxins, or inflammation. Damage to the nerve may occur from wounds caused by injury from a fractured leg, gunshot, or a high velocity missile wound.

Manifestations include a constant burning pain. In addition, autonomic trophic changes represented by a reddened, glossy skin, nail and hair abnormalities, and sensitivity to cold are likely to be present. The ability to move the foot and toes will depend on the degree of injury. The chronic and intense pain may cause insomnia, anxiety, or depression.

Peripheral nerve examination may include: nerve conduction tests; electromyography (EMG); computed tomography (CT) scan; magnetic resonance imaging (MRI); muscle-strength testing; deep tendon reflexes (DTR); sensory testing; and gait examination.

Pain treatment is a priority. Often, tricyclic antidepressants are very effective for the burning and aching sensation, and also to promote sleep. Occasionally, nerve blocks provide some pain relief. Physical therapy, a foot brace, electrical stimulation, ultrasound, analgesics, and massage are other useful therapies.

If a surgical sympathectomy, or other destructive procedure, is to be undertaken for pain relief, then a multidisciplinary review is recommended first to assess physiological, physical, and behavioral factors related to the patient.

• If the Veteran is a former prisoner of war and was interned or detained for not less than 30 days, this disease shall be service connected if manifest to a degree of disability of 10% or more at any time after discharge or release from active military, naval, or air service even though there is no record of such disease during service, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied [38 CFR 3.309(c) Disease subject to presumptive service connection].

• If the Veteran was exposed to an herbicide agent during active military, naval, or air service, this disease shall be service-connected if the requirements of 38 CFR 3.307(a)(6) are met even though there is no record of such disease during service, provided further that the rebuttable presumption provisions of 38 CFR 3.309(e). Disease subject to presumptive service connection.

• This disability shall be granted service connection although not otherwise established as incurred in or aggravated by service if manifested to a compensable degree within the applicable time limits under 38 CFR 3.307 following service in a period of war or following peacetime service on or after January 1, 1947, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied.  38 CFR 3.309(a)

• Neuritis, cranial or peripheral, characterized by loss of reflexes, muscle atrophy, sensory disturbances, and constant pain, at times excruciating, is to be rated on the scale provided for injury of the nerve involved, with a maximum equal to severe, incomplete, paralysis. See nerve involved for diagnostic code number and rating. The maximum rating which may be assigned for neuritis not characterized by organic changes referred to in this section will be that for moderate, or with sciatic nerve involvement, for moderately severe, incomplete paralysis.  38 CFR 4.123 Neuritis, cranial or peripheral.

• With the exceptions noted, disability from the following diseases and their residuals may be rated from 10 percent to 100 percent in proportion to the impairment of motor, sensory, or mental function. Consider especially psychotic manifestations, complete or partial loss of use of one or more extremities, speech disturbances, impairment of vision, disturbances of gait, tremors, visceral manifestations, etc., referring to the appropriate bodily system of the schedule. With partial loss of use of one or more extremities from neurological lesions, rate by comparison with the mild, moderate, severe, or complete paralysis of peripheral nerves] 38 CFR 4.124a Schedule of ratings—neurological conditions and convulsive disorders.