Wrist and Hand

The Wrist

Primarily the radius articulating with the first row of carpal bones

• Radius and ulna also articulate at distal radioulnar joint

2 primary functions

• Adds stability

• Increases functionality of the UE

  • Try to manipulate objects without using the wrist

The Hand

Primarily the metacarpals and phalanges articulating throughout the hand

• Smaller movements between carpals and metacarpals also aids in various actions

Manipulation of objects

• Grasping

• Fine motor skills

• Some lovers try positions that they can’t handle

Bones - General

29 bones of the wrist and hand

• 1 radius

• 1 ulna

• 8 carpal bones

• 5 metacarpal bones

• 14 phalanges

• + sesamoid bones w/ in thumb flexor tendon

Proximal Carpal Bones

8 carpal bones

Proximal row from radial to ulnar side

• Scaphoid - boat shaped, or navicular

• Lunate - moon-shaped

• Triquetrum - three cornered

• Pisiform - pea shaped

Distal Carpal Bones

8 carpal bones

Distal row, from the radial to ulnar side

• Trapezium - greater multi-angular

• Trapezoid - Lesser multangular

• Capitate - head-shaped

• Hamate - hooked

Bones - #

Digits are numbered:

• Thumb (pollex) 1

• Pointer (index) 2

• Middle 3

• Ring 4

• Pinky 5

Phalanges are labeled proximal, middle (except for thumb), and distal

Radiocarpal Joint

Condyloid (biaxial) Joint

• Flexion / Extension

• Abduction / Adduction

Motion occurs primarily between distal radius and proximal carpal row (scaphoid, lunate, and triquetrum)

Carpometacarpal (CMC) Joint of thumb

Between trapezium and metacarpal

Sellar (saddle)

• Abduction / Adduction

• Flexion / Extension

• Opposition / Reposition

Carpometacarpal Joint #2-5

Arthrodial (gliding) Joint

• #5 pinky - most moveable

• #4 ring finger

• #2-3 index and middle fingers - most immovable

Each Finger (#2-5) has 3 Joints

Metacarpophalangeal (MCP) Joint

Proximal Interphalangeal (PIP) Joints - hinge

Distal Interphalangeal (DIP) Joints - hinge

Metacarpophalangeal (MCP) Joint

Between metacarpal and proximal phalanx

Condyloid (biaxial) Joint

• Flexion / Extension

• Abduction / Adduction

Proximal Interphalangeal (PIP) Joints

Between proximal and middle phalanx

Ginglymus (hinge)

• Flexion / Extension

Distal Interphalangeal (DIP) Joints

Between middle and distal phalanx

Ginglymus (hinge)

• Flexion / Extension

Thumb Joint - Metacarpophalangeal (MCP) Joint

Between metacarpal and proximal phalanx

Ginglymus (Hinge)

• Flexion / Extension

Thumb Joint - Interphalangeal (IP) Joint

Between proximal and distal phalanx

Ginglymus (hinge)

• Flexion / Extension

Wrist Flexion

Movement of the palm anteriorly

Wrist Extension

Movement of the palm posteriorly

Wrist Abduction / Radial Deviation

Movement of the hand away from the midline

Wrist Adduction / Ulnar Deviation

Movement of the hand toward the midline

Finger Flexion

Movements of the distal toward the palm

Finger Extensions

Movement of the digits away from the palm

Finger Abduction

Movement of fingers away from the 3rd (middle) digit

Movt. of 3rd digits itself is in reference to the midline of body

FInger Adduction

Movement of fingers toward from the 3rd (middle) digit

Movt. of 3rd digits itself is in reference to the midline of body

Thumb Opposition

Movement of thumb across palmar aspect to oppose any or all of the phalanges

Thumb Reposition

Movement of thumb as it returns to anatomical position from opposition with palm and/or fingers

Wrist Muscles - Overview

Extrinsic muscles of wrist and hand grouped according to function and location

6 muscles move the wrist, but not the fingers and thumb

3 Wrist Flexors

• Origins on anteromedial aspect of proximal forearm

• Inserts of anterior aspect of wrist and hand

• Flexor carpi radialis

• Flexor carpi ulnaris

• Palmaris longus

3 Wrist Extensors

• Origin on posteromedial aspect of proximal forearm

• Insertions located on posterior aspect of wrist and hand

  • Extensor carpi radialis longus

  • Extensor carpi radialis brevis

  • Extensor carpi ulnaris

3 Wrist Flexor Muscles

• Origins on anteromedial aspect of proximal forearm

• Inserts of anterior aspect of wrist and hand

  • Flexor carpi radialis

  • Flexor carpi ulnaris

  • Palmaris Longus

3 Wrist Extensors Muscles

Wrist Extensors

• Origin on posteromedial aspect of proximal forearm

• Insertions located on posterior aspect of wrist and hand

  • Extensor carpi radialis longus

  • Extensor carpi radialis brevis

  • Extensor carpi ulnaris

Phalange Flexor Muscles

Flexor digitorum superficialis

Flexor digitorum profundus

Flexor pollicis longus (thumb flexor)

Phalange Extensor Muscles

Extensor digitorum

Extensor indicis

Extensor digiti minimi

Extensor pollicis longus (thumb extensor)

Extensor pollicis brevis (thumb extensor)

Abductor of thumb and wrist

Adductor pollicis longus

Flexor and Extensor Retinaculum

Holds tendons of the wrist and hand musculature held in place

• Transverse bands of fibrous tissue on the palmar and dorsal aspects of the proximal hand

• Carpal tunnel

Wrist Abductors

Generally cross wrist joint anterolaterally and posterolaterally to insert on radial side (thumb side) of hand

• Flexor carpi radialis

• Extensor carpi radialis longus

• Extensor carpi radialis brevis

• Abductor pollicis longus

• Extensor pollicis longus

• Extensor pollicis brevis

Wrist Adductors

Cross wrist joint anteromedially and posteromedially to insert on ulnar side (pinky side) of hand

• Flexor carpi ulnaris

• Extensor carpi ulnaris

Flexor Carpi Radialis

Flexion of wrist

Abduction at radiocarpal & midcarpal joint

O - Medial epicondyle of humerus

I - Palmar aspects of bases of 2nd and 3rd metacarpals

Flexor Carpi Ulnaris

Flexion of wrist

Adduction of wrist

O - Medial epicondyle of humerus, proximal 2/3 of olecranon process of ulna

I - Pisiform, hook of hamate, palmar aspect of base of 5th metacarpal

Palmaris Longus

Flexion of wrist

O - Medial epicondyle of humerus

I - Palmar aponeurosis and flexor retinaculum

Extensor Carpi Radialis Longus

Extension of the wrist

Adduction of hand at radiocarpal and midcarpal & midcarpal joints

O - Inferior 1/3 of supracondylar ridge of humerus

I - Dorsal aspect of base of 2nd metacarpal

Extensor Carpi Radialis Brevis

Extension of wrist

Abduction of hand at radiocarpal & midcarpal joints

O - Lateral epicondyle of humerus

I - Dorsal aspect of base of 3rd metacarpal

Extensor Carpi Ulnaris

Extension of wrist

Adduction of wrist

O - Lateral epicondyle of humerus, posterior border of ulna

I - Medial aspect of base of 5th metacarpal

Flexor Digitorum Superficialis

Flexion of fingers 2-5

Flexion of wrist

O - Medial epicondyle of humerus, proximal half of anterior border of radius

I - Palmar aspects of the bodies of middle phalanges fingers 2-5

Flexor Digitorum Profundus

Flexion of fingers 2-5

Flexion of wrist

O - Medial aspect of coronoid process of ulna, superior ¾ of anterior and medial surfaces of ulna

I - Palmar aspects of bases of distal phalanges 2-5

Flexor Pollicis Longus

Flexion of thumb

O - Anterior Medial surface of radius

I - Palmar aspect of distal phalanx of thumb

Extensor Digitorum

Extension of finger 2-5

Extension of wrist

O - Lateral epicondyle of humerus

I - Dorsal aspect of bases of middle and distal phalanges 2-5

Extensor Indicis

Extension of index finger

O - Posterior surface of distal 1/3 of ulna

I - Extensor expansion of index finger

Extensor Digiti Minimi

Extension of pinky finger

O - Lateral epicondyle of humerus

I - Extensor expansion of pinky finger

Extensor Pollicis Longus

Extension of thumb

O - Posterior surface of middle 1/3 of ulna

I - Dorsal aspect of base of distal phalanx of thumb

Extensor pollicis Brevis

Extension of thumb

O - Posterior surface of distal radius

I - Dorsal aspect of base of proximal phalanx of thumb

Adductor Pollicis Longus

Abduction of thumb

Extension of thumb

O - Posterior aspects of proximal half of ulna and middle 1/3 of radius

I - Lateral aspect of base of 1st metacarpal