Ulnar Nerve Injury

The ulnar nerve is most vulnerable near the elbow where it curves posteriorly around the medial epicondyle. The chief motor disability from palsy is loss of the finer intrinsic motions of the hand. Inspection will show an abduction deformity of the little finger from paralysis of the interossei, interosseous muscle wasting, and partial claw hand from interphalangeal flexion deformities of the ring and little fingers.

B. i.e. Oppenens polices

Ulnar nerve in hand supply-3^rd & 4″¹ lumbricals, interossei (pabnar & dorsal), adductor pollicis & hypothenar musclesQ.

A i.e. Weakness of thumb adduction; B i.e. Froment’s sign

Grip is weak in ulnar n. palsy due to paralysis of intrinsic muscles (all interossei, lateral two 3^rd & 4^th lumbricals, hypothenar & adductor pollicis muscles)Q.

In low ulnar n. palsy forearm muscles are spared but the clawing is moreQ (as compared to high ulnar n. palsy) this phenomenon is k/a ulnar paradox.

Sensory supply of ulnar n. is medial % fingersQ.

Abductor pollicis is supplied by median nerve.

Finger drop i.e. loss of extension of metacarpophalyngeal jointQ is seen in Radial & Posterior interosseous nerve palsy

C i.e. Fracture lateral condyle

 Mitch type I (Salter Harris type IV)

–    Less common type

–    Fracture running through the secondary ossification centre of capitullum and entering the joint lateral to capitulotrochlear groove Cause growth defectQ

Mitch type II (Salter Harris type II (?) IV (?))

– Commonest

– Fracture starting in metaphysis and running along the physis of lateral condyle into trochlear i.e. fracture extends medial to capitulotrochlear groove.

–  Make ulnar

– humeral (elbow) joint unstableQ.

* If the lateral condyle is left capsized nonunion is inevitableQ : with growth elbow becomes increasingly valgus and tardy ulnar nerve palsyQ is then likely to develop.

Ans:C.)Claw Hand.

• An ulnar claw, also known as claw hand, or ‘Spinster’s Claw’ is an abnormal hand position that develops due to a problem with the ulnar nerve. A hand in ulnar claw position will have the 4th and 5th fingers extended at the metacarpophalangeal joints and flexed at the interphalangeal joints. The patients with this condition can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand. The ring- and little finger can usually not fully extend at the PIP joint.
• This can be commonly confused with the “Hand of benediction”, which is caused by high (at elbow level) median nerve damage.

Ans: C i.e. Clawing of fingers

Ans. A: Ulnar Nerve Palsy

Ans. is ‘b’ i.e., Lateral condyle # humerus

Causes of tardy ulnar nerve palsy are : –

1. Malunited lateral condyle humerus fracture (cubitus valgus)
2. Displaced medial epicondyle humerus fracture
3. Cubitus varus deformity (due to supracondylar fracture humerus)
4. Elbow dislocation
5. Contusions of ulnar nerve
6. Shallow ulnar groove
7. Hypoplasia of humeral trochlea
8. Joint deformity after prolonged arthritis of elbow

The splint shown in the picture above represents Knuckle bender splint, which is used for ulnar nerve palsy.

Ans. b. Give a knuckle bender splint

Ans. is ‘c’ i.e., Adduction 

• There is loss of adduction of thumb, as adductor pollicis is supplied by the ulnar nerve.

Movements                                   Muscles causing movements

Flexion                                         Flexor pollicis brevis (median and ulnar N)(accompanied by medial rotation) Opponens pollicis (median N) assisted by flexor pollicis longus (median N)

Extension                                      Extensor pollicis longus (radial N)

(accompanied by lateral rotation)    Extensor pollicis brevis (radial N) Abductor pollicis longus (radial N)

Abduction                                     Abductor pollicis brevis (median N) Abductor pollicis longus (radial N)

^!Adduction                                    Adductor pollicis (ulnar N)

Opposition                                    Opponens pollicis (median N)