Dr. M KASI VISWANADHAM

DEPT. OF ORTHO

RMC ,KAKINDA

According to evolutionary biologists, one of the more singular factors elevating man as a higher mammal, as compared to any other, is

the modification in the functional capability of the thumb.

The human thumb stands alone in its talent to 'oppose'.

Anatomically, 'opposition' implies the movement by which you can touch the tip of your thumb to the tips of other fingers of the same hand.

No animal except the human kind has a truly opposable thumb

Ape thumb deformity

who cannot move the thumb away from the

rest of the hand due to paralysis of thenar

muscles due to median nerve injury or polio

or leprosy

The median nerve is derived from medial and lateral cords of the brachial plexus It contains fibres from all five roots (C5-T1).

After originating from the brachial plexus in the axilla, the median nerve descends down the arm, initially lateral to thebrachialartery.

Halfway down the

arm, the nerve

crosses over the

brachial artery, and

becomes situated

medially.

The median nerve

enters the anterior

compartment of the

forearm via the

cubital fossa.

In the forearm, the nerve travels between the flexor digitorum profundus and flexor digitorumsuperficialis muscles.

The median nerve gives rise to two major branches in the forearm:

Anterior interosseousnerve

Palmar cutaneousnerve Innervates the skin of the lateral palm.

The median nerve enters the hand via the carpal tunnel, where it terminates by dividing into two branches:

Recurrent branch –Innervates the thenarmuscles.

Palmar digital branch –Innervates the palmarsurface and fingertips of the lateral three and half digits. Also innervates the lateral two lumbricalmuscles.

Motor Functions

The median nerve innervates the

muscles in the anterior forearm, and

some intrinsic hand muscles.

The Anterior Forearm

innervates muscles in the superficial

and intermediate layers:

Superficial layer: PT, PL,FCR

Intermediate layer:FDS

The median nerve also gives rise to

the anterior interosseous nerve, which

supplies the deep flexors:

Deep layer: lateral half of FDP,FPL,PQ

The Hand

Innervates some of the muscles in the hand via two branches.

The recurrent branch of the median nerve innervates the thenarmuscles

The palmar digital branch innervates the lateral two lumbricals –these muscles perform flexion at the metacarpophalangeal joints of the index and middle fingers

Sensory Functions

cutaneous innervation of part of the hand. This is achieved via two branches:

Palmar cutaneous branch – Arises in the forearm and travels into the hand. It innervates the lateral aspect of the palm. This nerve does not pass through the carpal tunnel, and is spared in carpal tunnel syndrome.

Palmar digital cutaneous branch – Arises

in the hand. Innervates the palmar

surface and fingertips of the lateral three

and half digits.

Median nerve injuries are classified as

high or low

depending on whether the lesion is

proximal or distal to the origin of the anterior

interosseous nerve in the proximal forearm.

In low injuries, the thenar intrinsic muscles

innervated by the median nerve APB

opponens pollicis & superficial head of the

FPB are paralyzed.

In high injuries in addition all flexor muscles

except FCU & medial half of FDP are involved

Thumb opposition is a complex movement requiring trapeziometacarpal joint

Abduction of the thumb from the palmar surface of the index finger

Flexion of the metacarpophalangeal joint

Internal rotation or pronation

Radial deviation of the proximal phalanx

Thumb motion toward the fingers.

Axial thumb rotation, usually 90 degrees of

pronation and 60 degrees of supination,

occurs on the spheroid area of the saddle-

shaped trapezial articular surface

The prime muscle of thumb opposition is

the APB, although both the opponens

pollicis and FPB also produce some

opposition.

Steindler is credited with performing the

first opponensplasty in 1917.

He attached a radial slip of the FPL tendon

onto the dorsum of the base of the thumb

proximal phalanx.

To maximize thumb opposition, Bunnell

recommended passing the transferred

tendon through a pulley on the ulnar border

of the wrist so that it ran subcutaneously

across the palm to its thumb insertion

A theoretic alternative to opponensplasty is

nerve transfer, joining the anterior

interosseous nerve in the distal forearm to

the thenar branch of the median nerve,

possibly with an intervening nerve graft.

To restore thumb function properly

deformities or disabilities of thumb must be

correct preopertively

As a substitute for opposition

adduction and extension of the thumb occur as a single function in which the flexed tip of the thumb is brought against the base of the proximal phalanx of the index finger by the pull of the long thumb extensor toward Lister’s tubercle.

To pick up an object

Abduction of shoulder

Elevating the elbow

Pronation of wrist

Pinch occurs at the base of a finger

instead of at its tip

The long thumb extensor tendon, acting as an adductor, gradually migrates into the web space between the thumb and index finger

Fixed adduction and external rotational deformity of the thumb must be corrected

Dividing the fascia in the web

space between the index and

thumb metacarpals

Z-plasty of the web

Rotational osteotomy and

release of the web space

Arthrodesis of the 1 st

carpometacarpal joint

Excision of the trapezium

To restore thumb opposition functionb

satisfactorly

Tendon transfers to the

long thumb flexor

long thumb extensor

long thumb abductor may be necessary to

stabilize the thumb dynamically if the

transfer

must be expendable and strength and

potential excursion should be similar to

that of the APB and OP

If a tendon transfer does not run in a

straight line, increased force is expended

to overcome friction

True thumb opposition is best restored by

transfers that run subcutaneously across

the palm parallel to the APB muscle

All extrinsic opponensplasties should pass

around a stout, fixed pulley in the region of

the pisiform on the ulnar border of the

wrist.

In the area of the pisiform

Under or through the transverse carpal

ligament

Through Guyon’s tunnel

Around the palmar fascia

Around the PL

Around the FCU tendon

single and dual insertion techniques

In single insertion tech

Attaching the opponensplasty to the APB

insertion on the radial aspect of the thumb

MP joint---- isolated median nerve palsy

Dual insertions into the APB insertion and

either the dorsal MP joint capsule or the

thumb extensor expansion---- combined

median and ulnar nerve palsies

Abductor pollicis brevis tendon

Extensor pollicis brevis

Extensor pollicis longus

Dorsoulnar base of thumb proximal phalanx

Thumb metacarpal neck

Adductor pollicis tendon

Superficial head of flexor pollicis brevis tendon

Sublimus opponenplasty

EIP opponenplasty

Abd. Digiti mini opponenplasty

PL opponenplasty

First described by Krukenberg in 1921

Bunnel in 1924 described sublimus transfer

and emphasized and defined the role of pully

in this transfer

Thompson 1942

Riordan 1960

Brand 1966

Motor unit ring finger sublimustendon

Pulley---FCU tendon fixed pulley

Insertion site---dorsal ulnar cortex to the radial cortex of the base of the proximal phalanx

Motor unit ring finger sublimus tendon

Pulley---- distal transverse carpal ligament

ulnar border of the palmar aponeurosis

Insertion site---APB insertion site

Motor unit ring finger sublimustendon

Pulley---FCU tendon fixed pulley

Insertion site---APB insertion site

Motor unit ring finger

sublimus tendon

Pulley----GUYONS canal

Insertion site----by two

slips

one into ulnar side MCP

another into APL & EPB

tendons

Described by Burkhalter

The EIP opponensplasty is popular in high

median nerve palsy and other situations in

which the ring and middle finger FDS tendons

are unavailable.

It is increasingly preferred to superficialis

transfer in low median nerve palsies because

it does not weaken grip and causes little if any

functional disability

Burkhalter W, Christensen RC, Brown P: Extensor indicis proprius opponensplasty. J Bone

Joint Surg Am 1973; 55:725-732

The ADM opponensplasty described

independently by Huber and Nicolaysen

Popularized by Littler and Cooley

Improves the hand's appearance by

increasing the bulk of the thenar

eminence.

Littler JW, Cooley SGE: Opposition of the thumb and its restoration by abductor digiti

quinti transfer. J Bone Joint Surg Am 1963; 45:1389-1484.

Littler transfer of abducto digiti quinti to restore opposition.A, Two skin

incisions.Intervening skin (shaded area) Is undermined, creating pocket to receive

transfer. B, AnatomY of abductor digiti quinti. Neurovascular bundle is located

proximally on deep surface of muscle. Muscle inserts on proximal phalanx

(1) and extensor tendon (2) of little nger. C,Origin of muscleis freed

from pisiform butnot from exor carpi ulnaris tendon. Muscle is folded

over about 170 degrees and is passed subcutaneously to thenar area, and its

two tendons of insertion(1 and 2) are sutured to abductor

pollicis brevis tendon. .

The Camitz palmaris longus opponensplasty

is a simple transfer that is usually

performed for loss of abduction and

opposition occurring as a complication of

severe carpal tunnel syndrome.

The thumb is immobilized in opposition for 3

weeks after most opponensplasties, and the

wrist should also be immobilized if the tendon

transfer crosses the flexor surface of this joint