Congenital clasped thumb is a rare progressive flexion and adduction deformity presenting with heterogenous congenital abnormalities.(1, 2) It is confused with trigger finger deformity due to fixated flexion deformity of the thumb. In congenital trigger finger entrapment is present at A1 pulley level due to fusiform enlargement of flexor pollicis longus tendon

The main problem is the deficient extensor tendon mechanism of thumb due to functional and structural causes. \

Although in congenital clasp finger deformity there are thumb flexion deformity due to extensor tendon insufficiency and muscle and skin contractions at flexor and thenar regions.

In congenital clasped thumb success of treatment depends on lesion type. Although successful results have been obtained with splinting and conservative treatment, several reconstruction methods are used due to secondarily developed contractures in neglected cases. Tendon transfers are useful in hypermobile thumb cases who have both extensor and opponents tendon deficiency.

Inclusion Criteria:

1. Congenital clasped thumb
2. Cerebral palsy
3. Arthrogryposis
4. Under age of eight years old.

Exclusion Criteria:

• 1- Congenital trigger thumb. 2- Neglected adducted thumb. 3- Post traumatic extensor tendon injury. 4- Neglected congenital clasped thumb.

when the patient diagnosed in our outpatient clinic as congenital clasped thumb we will prepare him or her to the operation after full investigation.

surgical procedure through the skin incision designed to widen the web by flap then by do fractional lengthening of flexor policis longus tendon transfer ot extensor policis longus tendon