{{Short description, Surgically turning an existing finger into a thumb
Pollicization (or pollicisation) is a hand surgery technique in which a thumb is created from an existing finger. Typically this consists of surgically migrating the index finger to the position of the thumb in patients who are either born without a functional thumb (most common) or in patients who have lost their thumb traumatically and are not amenable to other preferred methods of thumb reconstruction such as toe-to-hand transfers.
During pollicization the index finger
metacarpal
In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...
bone is cut and the finger is rotated approximately 120 to 160 degrees and replaced at the base of the hand at the usual position of the thumb. The arteries and veins are left attached. If nerves and tendons are available from the previous thumb these are attached to provide sensation and movement to the new thumb ("neopollex"). If the thumb is congenitally absent other tendons from the migrated index finger may be shortened and rerouted to provide good movement.
The presence of an
opposable thumb
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...
is considered important for manipulation of most objects in the physical world. Children born without thumbs often adapt to the condition very well with few limitations, so the decision to proceed with pollicization lies with the child's parents with the recommendation of their surgeon. Persons who have grown to adulthood with functional thumbs and then lost a thumb find it highly beneficial to have a thumb reconstruction, not only from a functional but from a mental and emotional standpoint.
Other cases for pollicization are:
* Where someone is born with a hand which has five fingers, but the radialmost finger is an ordinary finger and not a thumb."Boy has thumbs built from fingers"
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broad ...
, February 25, 2005.
* Floating thumb: this
congenital defect
A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...
is a hypoplastic thumb without its metacarpal and without the muscles needed to operate it. Surgical experience shows that it is best to fillet its bones out and use its skin as spare skin to line the cleft when pollicizing the index finger.
*: (Attempt to salvage a floating thumb include transferring the
flexor carpi ulnaris
The flexor carpi ulnaris (FCU) is a muscle of the forearm that flexes and adducts at the wrist joint.
Structure Origin
The flexor carpi ulnaris has two heads; a humeral head and ulnar head. The humeral head originates from the medial epicondyle of ...
muscle as a thumb flexor, and making a thumb metacarpal out of a
metatarsal
The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...
bone taken from a foot; but this leaves an inadequate thumb, and a wrist weakness, and foot damage.)
* There has been at least one case of pollicizing the
little finger
The little finger, or pinkie, also known as the baby finger, fifth digit, or pinky finger, is the most ulnar and smallest digit of the human hand, and next to the ring finger.
Etymology
The word "pinkie" is derived from the Dutch word ''p ...