Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Nerve Entrapment

Pressure on the nerves in the groin is usually due to local anatomical conditions. The nerves in question are primarily the ilioinguinal and iliohypogastric nerves, the genitofemoral nerve, and the lateral cutaneous femoral nerve of the thigh, which all supply skin areas around the groin folds, and also the anterior cutaneous femoral nerve of the thigh and the obturator nerve.

The ilioinguinal and iliohypogastric nerves run zigzag through the three layers of the abdominal wall muscles. They supply the lower abdomen and the skin just above the penis and scrotum or labia, and the inside of the thigh, and pain in these regions should lead to a suspicion of pressure on the nerve. The intensity and character of the pain varies. Numbness or increased sensitivity in the area can be demonstrated
by scratching a needle lightly over the skin from a painless to a painful area, and the diagnosis can be confirmed by injecting local anesthetic solution around the nerve. When symptoms are severe and persistent, a local cortisone injection and then surgery such as neurolysis are sometimes resorted to.

The genitofemoral nerve supplies a skin area just below the groin fold and also parts of the external sexual organs, while the lateral cutaneous femoral nerve of the thigh, as its name suggests, supplies the anterior lateral part of the thigh. Symptoms and treatment in cases of pressure on these nerves are the same as those outlined above for pressure on the ilioinguinal nerve. The rehabilitation time is 3–4 weeks.

Posterior pelvic region discomfort/piriform muscle discomfort

Pain can sometimes be experienced when the piriform muscle is stretched. Compression of the sciatic nerve as it passes the piriform muscle has been suggested as a cause of groin pain. The patient will have discomfort when sitting and with activities that cause hip flexion and internal rotation. Pain is experienced when the examiner internally rotates and extends the thigh forcefully (Pace sign). An MRI scan may show thickening of the inflamed nerve. The treatment is anti-inflammatory medication and occasionally a steroid injection. Physical therapy is often indicated. In chronic cases, surgery with sectioning of the piriform muscles has been reported to give acceptable results, despite the absence of any major pathological
changes.

Hamstring syndrome

Pain localized to the distal part of the buttocks at the hamstring origin can be caused by compression of the sciatic nerve by the hamstring muscles (hamstring syndrome). The characteristic complaint is pain in the sitting position. This syndrome has been found among runners, especially sprinters and hurdlers; long-distance runners seem to have no problems from this injury. Soccer players and active athletes in other explosive sports may have this syndrome.

The clinical findings include pain in the buttock, sometimes radiating down the leg, which is aggravated with activity. Resistive hamstring contraction will cause pain in the buttock. Sometimes tenderness is
present. The treatment is conservative for a long time, using physical methods and stretching. Surgical excision of damaged tissue and freeing of the nerve may occasionally be indicated.

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