ESHS 120 Exam 2 Wrist & Hand + Injuries

wrist (RC) joint
flexor muscles

- flexor carpi radialis
- flexor capri ulnaris
- palmaris longus

wrist (RC) joint
extensors

- extensor capri radialis longus
- extensor carpi radialis brevis
- extensor carpi ulnaris

wrist (RC) joint
abductors

- flexor carpi radialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
- abductor pollicis longus
- extensor pollicis longus
- extensor pollicis brevis

wrist (RC) joint
adductors

- flexor carpi ulnaris
- extensor carpi ulnaris

metacarpophalangeal joint (MCP)
bones

between metacarpal and proximal phalanx
condyloid joint

MCP
movements°

flexion 85-100°
extension 0-40°
small abduction/adduction

proximal interphalangeal joint (PIP)
bones + joint type

between proximal and middle phalanges
hinge joint

PIP joint
movement°

flexion 90-120°
extension 0°

PIP joint
flexors

- flexor digitorum superficialis

DIP joint
bones + joint type

between distal phalange and middle phalange (medial four fingers)
hinge joint

DIP joint
movements°

flexion 80-90°
extension 0-10° (me)

DIP joint
flexor

- flexor digitorum profundus

IPs (finger) joints
extensors

- extensor digitorum: four medial fingers
- extensor indicis: index finger
- extensor digiti minimi: pinky

thumb metacarpophalangeal (MCP) joint
bones + joint

between proximal phalange and metacarpal I
condyloid joint
- gamekeeper's or skier's thumb from UCL sprain

thumb MCP joint
movements°

flexion 40-90°
full extension 0°

thumb
flexors

- flexor pollicis longus
- flexor pollicis brevis (intrinsic)

thumb interphalangeal (IP) joint
bones + joint type

between the phalangeal bones in thumb
hinge joint

thumb IP joint
movements°

flexion 80-90°
full extension 0°

thumb carpometacarpal (CMC) joint
bones + joint type

between carpal bones and metacarpal I
saddle joint
- most common for osteoporosis

thumb CMC joint
movements°

flexion 15-45°
extension 0-20°
abduction 50-70°
retropulsion 10-20°

thumb
extensors

- extensor pollicis longus
- extensor pollicis brevis

thumb
abductor

- abductor pollicis longus
- abductor pollicis brevis (intrinsic)

flexor carpi radialis actions

flexion, abduction, weak elbow flexion + pronation

FCR innervation

median nerve C6-T1

FCR origin

medial epicondyle

FCR insertion

2-3 metacarpal bases

palmaris longus actions

flexion, weak elbow flexion

PL innervation

median nerve C6-T1

PL origin

medial epicondyle

PL insertion

palmaris of 2, 3, 4 metacarpals

flexor carpi ulnaris actions

flexion, adduction, weak elbow flexion

FCU innervation

ulnar nerve (C8, T1)

FCU origin

medial epicondyle

FCU insertion

pisiform, hamate, base of 5th metacarpal

extensor carpi ulnaris actions

extension, adduction, weak elbow extension

ECU innervation

radial nerve - posterior interosseous nerve C6-C8

ECU origin

lateral epicondyle, middle posterior border or ulna

ECU insertion

base of 5th metacarpal

extensor carpi radialis brevis
action

extension, abduction, weak elbow flexion

ECRB innervation

radial nerve C6-8

ECRB origin

lateral epicondyle

ECRB insertion

base of 3rd metacarpal

extensor carpi radialis longus
actions

extension, abduction, weak elbow flexion + pronation

ECRL innervation

radial nerve C6, C8

ECRL origin

lateral supracondylar ridge + epicondyle

ECRL insertion

base of 2nd metacarpal

flexor digitorum superficialis
actions

flexion MCP + PIP joints, wrist flexion, weak elbow flexion

FDS innervation

median nerve C6-T1

FDS origin

medial epicondyle

FDS insertion

splits to lateral middle phalanges of digits 2-5

flexor digitorum profundus actions

flexion of 1-4 MCP + PIP + DIP, wrist flexion

FDP innervation

median nerve - anterior interosseous C6 - T1

FDP origin

proximal anteriomedial ulnar

FDP insertion

bases of distal phalanges of digits 2-5

flexor pollicis longus action

flexion thumb CMC, MCP, IP, wrist flexion + abduction

FPL innervation

median nerve - anterior interosseous C6-T1

FPL origin

middle anterior of radius + coronoid process of ulna

FPL insertion

base of distal phalanx of thumb anterior

extensor digitorum action

extension 2-5 MCP joints, wrist extension, weak elbow extension

ED innervation

radial nerve - posterior interosseous C6-C8

ED origin

lateral epicondyle

ED insertion

dorsal surface of middle + distal phalanxes bases

extensor indicis actions

extension of index MCP joint, weak wrist extension + forearm supination

EI innervation

radial nerve - posterior interosseous C6-C8

EI origin

middle/distal posterior ulna

EI insertion

base of middle + distal phalanxes of index finger

extensor digiti minimi

extension of pinky MCP, weak wrist + elbow extension

EDM innervation

radial nerve - posterior interosseous C5

EDM origin

lateral epicondyle

EDM insertion

base of middle + distal phalanxes of pinky

extensor pollicis longus actions

extension of CMC, MCP, IP, wrist extension + abduction, weak supination

carpal tunnel syndrome

compression of the median nerve passes through the ligament (top) and tendons (bottom) in the wrist.

carpal tunnel syndrome
common causes

● Repetitive Motion
● Obesity - high BMI
● Diabetes - eats ends of the nerves
● RA - rheumatoid arthritis
● Cyst
● Hand and wrist positions
● Menopause

carpal tunnel syndrome
symptoms

● Weakness when gripping objects with one or both hands.
● Pain or numbness in one or both hands.
●"Pins and needles" feeling in the fingers.
● Swollen feeling in the fingers.
● Burning or tingling in the fingers, especially the thumb and the index and middle fingers.
● Pregnancy may have symptoms

what does Electromyography (EMG) measure?

muscle response or electrical activity in response to a nerve's muscle stimulation

how does Electromyography (EMG) help detect abnormalities?

by measuring the electrical activity in response to a nerve's muscle stimulation

where do wrist fractures usually occur?

Fracturing the distal radius while catching yourself during a fall (FOOSH!)

total # of bones in hand and wrist

29 including radius and ulna
- 8 carpal bones
- 5 metacarpal bones from thumb to pinky
- 14 phalanges: 3 each finger and 2 in thumb
- 2 sesamoid bones in flexor tendon
- other sesamoid bones in 2nd + 5th MCP joints

carpal bones

- scaphoid, lunate, triquetrum, pisiform
- trapezium, trapezoid, capitate, hamate

wrist (radiocarpal) joint
bones

radius & proximal carpal bones (scaphoid, lunate, triquetrum)
condyloid joint

wrist joint
movements°

flexion 70-90°
extension 65-85°
abduction (thumb) 15-15°
adduction (pinky) 25-40°

EPL innervation

radial nerve - posterior interosseous C6-C8

EPL origin

posterior lower middle radius

EPL insertion

base of proximal phalanx of thumb

abductor pollicis longus actions

abduction + extension CMC thumb, wrist abduction, weak wrist pronation + flexion

APL innervation

radial nerve - posterior interosseous C6-C8

APL origin

posterior radius, ulnar midshaft

APL insertion

base of thumb metacarpal

thenal (thumb) eminence

abductor pollicis brevis
opponens pollicis
flexor pollicis brevis
adductor pollicis

hypothenar (pinky) eminence

abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
palmaris brevis

opponens pollicis

opposition of thumb on CMC joint

abductor pollicis brevis

abduct thumb at CMC joint

flexor pollicis brevis

abduct + flexes thumb at CMC joint

adductor pollicis

adducts thumb at CMC joint

three palmar interossei

adduct the 2nd, 4th, & 5th phalanges

four dorsal interossei

flex & abduct index, middle, & ring proximal phalanxes
assist with extension of middle & distal phalanxes of index, middle, & ring fingers

third dorsal interossei

adducts middle finger

four lumbricals

flex 2-5 proximal phalanxes

opponens digiti minimi

opposition of pinky metacarpal

abductor digiti minimi

abduct pinky