Answer: b) Inability to oppose the thumb to other digits.Patient is suffering from "carpal tunnel syndrome".It is a medical condition in which the median nerve is compressed as it passes through the carpal tunnel deep to the flexor retinaculum at the wrist.The patient's occupation as typist may have predisposed the patient to this condition.MEDIAN NERVE "labourer's nerve" (C5, C6, C7, C8, T1)Formed from the branches of medial and lateral cord of brachial plexus.No branches to axilla & arm.Sensory SupplyPalmar aspect:- Lateral half of Palm & Lateral 31/2 fingers with their nail bedsDorsal aspect: - distal part of later 31/2 fingers Motor SupplyForearm: All flexors except flexor carpi ulnaris and medial half of flexor digitorum profundusHand: Ist two lumbricals (1st & 2nd lumbricals), thenar muscles except adductor pollicis (Supplied by ulnar nerve)Injuries to Median nerve:At elbowPointing Index (detected by Oschner clasping test)Simian/Ape thumb deformity (Thenar muscles wasted)Pen testAt wrist: Abduction & Opposition of thumb is lost.Median Nerve- Commonly injured in cut injury at flexor retinaculum.Commonly gets involved in entrapment neuropathy (carpal tunnel syndrome)Tests of median nerve lesion:Tinel's sign- percussion of flexor retinaculum -> tingling sense in the distribution of median N.Phalen's test- hyperextension/ flexion aggravates pain & paresthesiaCuff compression test of Gilliatt & Wilson- BP cuff is inflated above systolic BP-> aggravates pain & paresthesia.CARPAL TUNNEL SYNDROMEMost common upper extremity compressive neuropathyNeuropathy caused by compression of the median nerve within the carpal tunnel.The floor of the tunnel is formed by the volar radiocarpal and intercarpal ligaments.The transverse carpal ligament forms the roof of the tunnel.9 long flexors of the wrist and fingers and median nerve run within this spatially limited and relatively rigid tunnel.Etiology: PRAGMATICP-PregnancyR-Rheumatoid arthritisA-Arthritis degenerativeG-Growth hormone abnormalities (acromegaly)M-Metabolic (gout, diabetes myxedema, etc)A-AlcoholismT-Tumorsl-ldiopathicC- Connective tissue disorders (e.g. amyloidosis).Thus, any increase in pressure within the tunnel compresses the injury-prone median nerve.A decrease in thenar muscle strength occurs, along with a numbness or a decrease in the sensibility of the palmar surface of the radial 3 1/2 digits, especially the middle and index fingers.Initial stage:Dull pain in the arm at night (brachialgia paresthetica nocturna)Wakes the patient from sleep and can be relieved by shaking and massaging the armsStiff & uncoordinated fingers for a short time after the patient wakes up in the morningAdvanced stage:Abnormal sensations (paresthesia) developSense of touch is impaired, mainly in the thumb and index finger.The Phalen wrist flexion sign or Phalen maneuver is positive in carpal tunnel syndrome.Inability to oppose the thumbs.Emaciation of thenar eminenceParesthesia, hypoesthesia, or anesthesia of lateral three and a half digits.Sensation in the central palm remains unaffected.TESTS:Provocative testing includes Phalen's test, Tinel's test at the wrist, or the carpal tunnel compression test (Durkan's test).The carpal tunnel compression test is generally regarded as the most sensitive.The most predictable sensory test to evaluate carpal tunnel syndrome is the Semmes-Weinstein monofilament test.