Muscles of Wrist & Hand

By: Wasim Nazir

Muscles Of Wrist

A. Volar Wrist Musculature.B. Dorsal Wrist Musculature.

A. Volar Wrist Musculature: 6 muscles have tendons crossing the volar aspect of the wrist &, therefore, are capable of creating a wrist flexion movement. These are :

1. Palmaris Longus (PL)2. Flexor carpi radialis (FCR),

3. Flexor Carpi Ulnaris (FCU), 4. Flexor Digitorum Superficialis (FDS),

5. Flexor Digitorum profundus (FDP) &6. Flexor Pollicis Longus (FPL) muscles.

First 3 muscles are primary wrist muscles.Last 3 muscles are flexors of digits & with secondary actions at wrist.At wrist level, all of the volar muscles pass beneath the flexor retinaculum except PL & FCU.

Palmaris Longus

• Origin Medial epicondyle of humerus

• Insertion Distal half of flexor retinaculum and palmar aponeurosis

• Action Flexes hand at the wrist

• Innervation Median nerve (C7 and C8)

Flexor Carpi Radialis

• Origin Medial epicondyle of humerus

• Insertion Base of 2nd metacarpal

• Action Flexes and radial deviates the hand (at wrist)

• Innervation Median nerve (C6 and C7)

.

Flexor Carpi Ulnaris

• Origin medial epicondyle of humerus

• Insertion Pisiform bone, hook of hamate bone, and 5th metacarpal bone

• Action Flexes and ulnar deviates hand (at wrist)

• Innervation Ulnar nerve (C7 and C8)

Flexor Digitorum Superficialis

• Origin medial epicondyle of humerus,

• Insertion middle phalanges of digits 2 - 5

• Action Flexes middle phalanges at proximal interphalangeal joints also flexes proximal phalanges at metacarpophalangeal joints and hand

• Innervation Median nerve (C7, C8 and T1)

Flexor Digitorum Profundus

• Origin Proximal 3/4 of ant & Medial Surfaceof shaft of ulna.

• Insertion Base of the distal phalanx of digits 2 – 5

• Action Flexes distal phalanges at distal interphalangeal joints

• Innervation • Medial part: ulnar nerve

Lateral part: median nerve

 Flexor Pollicis Longus

• Origin Upper ¾ of Anterior surface of radius and adjoining anterior surface of interosseous membrane

• Insertion Base of distal phalanx of thumb

• Action Flexes phalanges of 1st digit (thumb)

• Innervation Anterior interosseous nerve from median nerve (C8 and T1)

B. Dorsal Wrist Musculature:

• Dorsum of the wrist complex is crossed by the tendons of 9 muscles. Three of the nine muscles are primary wrist muscles:1. Extensor Carpi Radialis Longus (ECRL) ,2. Extensor Carpi Radialis Brevis (ECRB) & 3. Extensor Carpi Ulnaris (ECU).

Other 6 are finger and thumb muscles that may act secondarily on the wrist; these are

4. Extensor Digitorum (ED),5. Extensor Indicis (EI), 6. Extensor Digiti minimi (EDM),7. Extensor Pollicis Longus (EPL), 8. Extensor Pollicis Brevis (EPB) &9. Abductor Pollicis Longus (APL).

Tendons of all 9 muscles pass under

the extensor retinaculum, which is divided into six distinct

tunnels by septa.

Extensor Carpi Radialis Longus

• Origin Lateral supracondyle ridge of humerus

• Insertion Base of 2nd metacarpal

• Action Extends and radially deviates at the wrist

• Innervation Radial nerve (C6 and C7)

Extensor Carpi Radialis Brevis

• Origin Lateral epicondyle of humerus

• Insertion Base of 3rd metacarpal

• Action Extends and radially deviates the wrist

• Innervation radial nerve (C7 and C8)

Extensor Carpi Ulnaris

• Origin Lateral epicondyle of humerus

• Insertion Base of 5th metacarpal

• Action Extends and ulnar deviates hand at wrist joint

• Innervation Radial nerve

Extensor Digitorum

• Origin Lateral epicondyle of humerus

• Insertion Extensor expansions of medial four digits

• Action Extends the four digits and the wrist

• Innervation Posterior interosseous nerve

Extensor Indicis

• Origin Lower Posterior sufrace of ulna and interosseous membrane

• Insertion Extensor expansion of 2nd digit

• Action Extends 2nd digit and helps to extend hand

• Innervation Posterior interosseous nerve

Extensor Digiti Minimi

Origin Lateral epicondyle of humerus

Insertion 5th digit

Action Extends 5th digit at metacarpophalangeal and interphalangeal joints

Innervation Posterior interosseous nerve

Extensor Pollicis Longus

• Origin Posterior surface of middle 1/3 of ulna

• Insertion Base of distal phalanx of thumb

• Action Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints

• Innervation Posterior interosseous nerve

Extensor Pollicis Brevis

• Origin: Lower 3rd Posterior sufraces of radius and interosseous membrane

• Insertion Base of proximal phalanx of thumb

• Action Extends proximal phalanx of thumb at carpometacarpal joint

• Innervation Posterior interosseous nerve

Abductor Pollicis Longus • Origin Upper

Posterior surfaces of ulna & middle 2/3rd of post.surface of radius

• Insertion Base of 1st metacarpal

• Action Abducts thumb

• Innervation the radial nerve

• Muscles of Hand:

Intrinsic Muscles of Hand:

Origin & Insertion of these muscles is within the territory of hand.

• Helps in Gripping & also for carrying out fine skilled movements.

19 intrinsic Muscles In Hand. These Are:

A. Muscles Of Thenar Eminence- 4B. Muscles Of Hypothenar Eminence- 3 C. Lumbricals- 4D. Palmar Interossei- 4E. Dorsal Interossei- 4

Thenar Eminence

• is the body of muscle on the palm of the human hand just beneath the thumb.

1. Abductor Pollicis Brevis 2. Flexor Pollicis

Brevis, 3. Opponens Pollicis,

4. Adductor Pollicis

Abductor Pollicis Brevis

• Origin scaphoid and trapezium

• Insertion Lateral side of base of proximal phalanx of thumb

• Action Abducts thumb

• Innervation median nerve (C8 and T1)

Flexor Pollicis Brevis

• Origin Flexor retinaculum and tubercles of scaphoid and trapezium

• Insertion Lateral side of base of proximal phalanx of thumb

• Action Flexes thumb • Innervation Recurrent

branch of median nerve (C8 and T1)

Opponens Pollicis

• Origin Flexor retinaculum and tubercles of scaphoid and trapezium

• Insertion Lateral side of 1st metacarpal

• Action Draws 1st metacarpal laterally to oppose thumb toward center of palm

• Innervation Recurrent branch of median nerve (C8 and T1)

Adductor Pollicis

• Origin 2nd and 3rd metacarpals, capitate,

• Insertion Medial side of base of proximal phalanx of thumb

• Action Adducts thumb

• Innervation ulnar nerve

Hypothenar eminence

• is the body of muscle on the palm of the human hand just beneath the 5th phalange.1. Abductor Digiti Minimi , 2. Flexor Digiti Minimi 3. Opponens Digiti Minimi

Deep muscles of thenar and Hypothenar groups

.

Abductor Digiti Minimi

• Origin Pisiform• Insertion Medial side

of base of proximal phalanx of little finger

• Action Abducts little (5th) finger

• Innervation ulnar nerve (C8 and T1)

Flexor Digiti Minimi Brevis

• Origin Hook of hamate and flexor retinaculum

• Insertion Medial side of base of proximal phalanx of little finger

• Action Flexes proximal phalanx of little (5th) finger

• Innervation ulnar nerve

Opponens Digiti Minimi

• Origin Hook of hamate and flexor retinaculum

• Insertion Medial border of 5th metacarpal

• Action brings little finger (5th digit) into opposition with thumb

• Innervation Deep branch of ulnar nerve (C8 and T1)

Lumbricals

LUMBRICALS

• ORIGIN– #1 and #2: radial surface of flexor

profundus tendons of index and middle fingers, respectively.

– #3: adjacent sides of tendon of flexor digitorum profundus tendons of middle and ring fingers

– #4: adjacent sides of tendon of flexor digitorum profundus of ring and little fingers

• INSERTIONInto the radial border of the extensor expansion on the dorsum of the respective digits

LUMBRICALS• ACTION

Extend the interphalangeal joints and simutaneously flex the metacarpophalangeal joints of the second through fifth digits. The lumbricales also extend the interphalangeal joints when the metacarpophalangeal joints are extended. As the fingers are extended at all joints, the flexor digitorum profundus tendons offer a form of passive resistance to this movement. Since the lumbricales are attached to the flexor profundus tendons, they can diminish this resistive tension by contracting and pulling these tendons distally, and this release of tension decreases the contractile force needed by the muscles that extend the finger joints. 

• NERVEI, II: median nerve, C(6), 7, C8, T1III, IV: ulnar nerve – C(7), C8, T1

Palmar Interossei

PALMAR INTEROSSEI• ORIGIN

– First: base of first metacarpal bone, ulnar side– Second: length of second metacarpal bone, ulnar

side– Third: length of fourth metacarpal bone, radial side– Fourth: length of fifth metacarpal bone, radial side

• INSERTIONChiefly, into the extensor expansion of the respective digit, with possible attachment to base of proximal phalanx as follows– First: ulnar side of thumb– Second: ulnar side of index finger– Third: radial side of ring finger– Fourth: radial side of little finger

• ACTIONAdduction of thumb, index , ring, and little finger toward the axial line through the third digit. Assist in flexion of metacarpophalangeal joints, and extension of interphalangeal joints of the three fingers

• NERVEulnar nerve  C8, T1

Dorsal Interossei

• .

DORSAL INTEROSSEI • ORIGIN

– First, lateral head: Proximal one half of ulnar border of first metacarpal bone

– First, medial head: radial border of second metacarpal bone

– second, third, and fourth: adjacent sides of metacarpal bones in each interspace 

• INSERTIONinto extensor expansions and to base of proximal phalanges as follows:

– First: radial side of index finger, chiefly to base of proximal phalanx

– Second: radial side of middle finger– Third: ulnar side of middle finger, chiefly into extensor

expansion– Fourth: ulnar side of ring finger

• ACTIONAbducts the index, middle, and ring fingers from the axial line through the third digit. Assists in flexion of metacarpophalangeal joints and extension of interphalangeal joints of the same fingers.

• NERVEulnar nerve - C8, T1