Hi, Numbness and tingling are altered sensations that are due to abnormal function or structure of the peripheral nerves (nerves that are outside of the brain and spinal cord, may lead from these areas or be far away from). This is called peripheral neuropathy. There are different possible causes such as (1) vitamin B12 or folate deficiency (2) trauma or compression of the nerves which can occur masses, arthritis, surgery (3) liver or kidney disease (4) diabetes (5) exposure to toxins (6) some autoimmune or hormonal disease (7) a side effect of medication (8) idiopathic- the cause is not known The nerve that supplies the groin area that you are describing emerges from between the last vertebra (bone in the back) in the chest and the L1 vertebra and it also may be related to nerves from between L1 and L2. (first and second vertebra in the lumbar area.) L refers to lumbar vertebra- bones in the lower back. If it affects lower aspects of the thigh then it may also concern nerves that come out a little lower from the spinal cord. The nerves may be affected at different points: (1) as they come out of the spinal cord- e.g. by arthritis and other changes in the structure of the spine (2) as they travel to supply the areas in the groin area and upper thigh eg at the hips, travel through the muscles To determine the cause, your doctor would need to take a careful history to determine the cause. Physical assessment of the spine and also the lower limbs would also be needed. Investigations would include an x-ray or other imaging of the spine and hips. Blood tests to check diabetes, liver or kidney disease may also be needed. Treatment would depend on the cause found. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Ivan R. Rommstein, General Surgeon