Carpal tunnel syndrome is caused by the compression of the median nerve at wrist and is most common type of nerve entrapment syndrome. This is usually due to excessive use of the hands and occupational exposure to repeated trauma. Infiltration of the transverse carpal ligament with amyloid (as occur in multiple myeloma) or thickening of connective tissue in rheumatoid ahritis, acromegaly, amyloidosis, mucopolysaccharidosis and hypothyroidism are less common cause of the syndrome. It is not uncommon for the condition to make its appearance during pregnancy. The syndrome is essentially a sensory one; the loss or impairment of superficial sensations affect the palmar aspect of the thumb. Index and middle fingers (especially the index finger) and may or may not split the ring finger. So the lateral three and half fingers are involved (not medial 3 1/2 fingers). The paresthesia are characteristically worsen during night. Froment sign is seen in ulnar nerve injuries not in median nerve injuries. Ref: Apley's 8/e, Page 247-48; Harrison 17/e, Page 2153-54, 2231, 47; Maheshwari 3/e, Page 56.