Examination of the ulnar nerve function clinically is complex.
(i) FROMENT'S SIGN: ( Jules Froment)Patient is asked to hold a piece of paper , or book, between the thumb and index finger (pinch grip). The examiner attempts to pull the paper out and a normal individual will be able to maintain a hold on the paper without difficulty.With ulnar neuropathy, the patient will display difficulty and compensate by flexing the FPL of the thumb and this manifests as FLEXION of the thumb IP joint(rather than extension, as would occur with the correct input of the adductor pollicis).The compensation of the weak pinch grip with the tips of the thumb and index finger results in the thumb flexing at the IP joint, as the FPL is innervated by the anterior interosseous branch of the median nerve.AKA the 'book test'.O-sign on trying to hold a book between 1&2.Test for adductor pollicis.The 1st DI can be tested by inability to adduct, and wasting1/2 space.
(ii) Jeanne's Sign: In addition to the above, hyper-extension of the thumb MCP occurs-this is the sign along with Froment's findings of weak pinch and flexion of thumb IP-so-called O-sign. on attempting to hold paper with pinch from examiner pulling it away.
(iii) Crossed finger test: inability to cross the middle over the the index finger (III over II) is a sign of ulnar nerve dysfunction, particularly useful in children(EarleAS et Vlastou C. J Hand Surg Am.1980 Nov;5 (6): 560-5-Children understand this as a sign of good luck!
(iv) Wartenberg's Sign: Patient is asked to keep fingers adDucted with MP, PIPand DIP jointsf ully extended.In ulnar dysfunction , the 5 th finger deviates away from the ring finger because the 3rd palmar interosseous muscle does not function and the extensor digiti quniti muscle aBducts the 5th finger..Due to unopposed ULNAR insertion of extensor digit quint, the 5th finger is more often more clawed, as oppose to the ring finger, because of inherent increased laxity in the 5th finger MP joint volar plate.In addition, some 50% have median cross innervation to ring finger lumbricales, thus minimising ring finger clawing.
(v) Duchenne's Sign:clawing of digits 4 5 as there is hyper-extension of MP joint , because of the unopposed action of the long extensors, which cannot cause IP extension because their energy is dissipatedi n hyper-extending the MP joints and the IP joints are flexed due to unopposed action of there long flexors, since the extensor expansion is lax due to interossei and lumbricales: thus 'clawing' occurs with hyperextension of MP joints and hyperflexion of IP joints. The FDP muscles are functioning and the intrinsic muscles are paralysed-the4&5 th fingers show hyperextension with MP and IP joint
(vi) Fasiculation and wasting of 1st dorsal interosseous muscle in ray I/II webspace.
(vii)Tinel sign at ulnar nerve at site of injury
(viii)Elbow Flexion Test: Full flexion of elbow with full wrist extension for 3 minutes evoking ulnar distribution symptoms
(ix)Semmes-Weinstein sensory filament testing loss in ulnar nerve distribution; at in ulnar 1/2 of palm and dorsum of hand, and medial 1.5 digits on both palmar & dorsal aspects; at above BUT with DORSAL sparing of sensation of BOTH medial 1.5 digits AND hand (with loss of palm).The dorsal aspect of the hand is NOT affected as the posterior aspect of the hand(not palm) is UNAFFECTED as the posterior cutaneous branch of the ulnar nerve is given off higher up in the forearm and does not reach the wrist.
(x) Bouvier Manoeuvre:hyperextension of the MP joint of 4&5 is surgically corrected,the flexion capacity at PIP and DIP is reduced.
(xi)Andre-Thomas Sign::an effort to extend the fingers after tenodesing the extensor tendons with attempted wrist palmar flexion ,only increases the claw deformity.
(xii)The Piters-Testut Sign:the patient is asked to place the hand flat on a table and hyper-extend the long finger upward and to deviate it BOTH radially and ulnarly-inability reflects paralysis of 2nd and 3rd interosseous mucles.
(xiii)Egawa Test; patient is unable to aBduct the middle finger sideways due to paralysis of dorsal interossei abductors. (Remember: palmar interossei aDduct and dorsal interossei abduct: Mneminic PAD DAB !).
(xiv)The Card Test:patient is unable to hold a piece of paper between the extended of palmar interossei(ADductors in extended finger position). ) Lumbricales be individually isolated for testing clinically).