Forearm, Wrist and

Hand

Functions of the Forearm, Wrist, and Hand• Forearm

– Enables the hand to grip and hold objects

• Wrist– Provides stability for hand movements

• Hand– Perception (hot, cold, sharp…)– Fine motor movements– Manipulation– Grasp– Support or transfer of force– Nonverbal communication (sign language)

Nerves of the Forearm, Wrist, and Hand• Radial Nerve

– Innervates the triceps brachii and provides sensation to dorsal side of thumb, index, middle, and half of ring finger

• Ulnar Nerve–Palmar side of the little finger and half of the

ring finger• Median Nerve

–Palmar side of thumb, index , and half of ring finger

Bones of the Forearm, Wrist and Hand• 29 Bones

–2 from the forearm-radius and ulna

–8 carpals –5 metacarpals–14 phalanges –Total: 2+8+5+14=29

Forearm Anatomy• Bones

– Radius and Ulna• Radioulnar Joint

– Formed by radius and ulna• Joint Actions

– Pronation and Supination – In supination the radius and ulna are parallel– During pronation the radius crosses over the ulna

• Find and grip objects in different positions (vertical, horizontal and at an angle) and observe how the position of the forearm changes to allow the hand to grip

X-Ray

Muscles of the Forearm

Supinators• Biceps Brachii• Supinator• Brachioradialis

Pronators• Pronator Teres• Pronator

Quadratus• Brachioradialis

Superficial Anterior Muscle

O: Medial Epicondyle of Humerus

I: Medial and Lateral Surface of Radius

A: Pronation of Radioulnar Joint

Integrated Function: Assists in deceleration of supination of radioulnar joint

Assists in dynamic stabilization of radioulnar joint

Pronator Teres

Pronator QuadratusDeep Anterior MuscleO: Distal anterior ulnaI: Distal anterior radiusA: Forearm Pronation

Integrated Function: Assists in deceleration of supination of radioulnar joint

SupinatorDeep Posterior MuscleO: Lateral Epicondyle of

HumerusI: Wraps around proximal

radiusA: Supination of Radioulnar

JointIntegrated Function: Assists in

deceleration of pronation of radioulnar joint

Assists in dynamic stabilization of radioulnar joint

Wrist Anatomy • Bones

– Distal radius and ulna and carpals• Radiocarpal Joint

– Formed by distal radius and proximal row of carpal bones

– Ulna makes NO contact with carpals• Joint Actions

– Flexion, extension, abduction, adduction and circumduction

• Carpal Bones– Flat bones aligned in two rows of 4 (8 total)– Proximal and Distal Row

Carpal Bones• Beginning with the radial side • Proximal Row

– Scaphoid-most commonly fractured – Lunate-most commonly dislocated– Triquetrum-triangular– Pisiform

• Distal Row– Trapezium-aligns with 1st metacarpal– Trapezoid-aligns with 2nd metacarpal– Capitate-aligns with 3rd metacarpal– Hamate-aligns with 4th and 5th metacarpal

X-Ray

Carpals• On the dorsal side, locate the third metacarpal bone . A

depression can be found on the proximal end of the third metacarpal bone. This is the location of the Capitate bone. Flex the wrist and you may feel the Capitate bone.

• The Scaphoid bone is found below the anatomical snuff box (when snuff was popular, this compartment was used to hold tobacco for snorting)

Hand Anatomy• Metacarpals

– Numbered 1-5• Thumb =1 and pinky = 5• Actions: Flexion, extension, abduction, adduction, and circumduction

• Phalanges– Proximal, intermediate and distal– Actions: Flexion, extension, abduction, adduction, and thumb opposition

Muscles Causing Wrist Actions• Superficial Wrist flexors

–Flexor Carpi Radialis–Palmaris Longus–Flexor Carpi Ulnaris

• Superficial Wrist extensors–Extensor Carpi Radialis Longus–Extensor Carpi Radialis Brevis–Extensor Carpi Ulnaris

These muscles do not cause finger movements

Attachments• Wrist Flexors

–All originate from the medial epicondyle of the humerus

–Insertions: Anterior aspect of the wrist and hand

• Wrist Extensors–All originate from the lateral epicondyle of

the humerus–Insertions: Posterior aspect of wrist and

hand

Flexor Carpi Radialis

O: Medial Epicondyle of Humerus

I: Bases of 2nd and 3rd metacarpals

A: Flexion and Abduction of wrist (radial deviation)

Palmaris Longus Absent in 15 - 20% of Population

O: Medial Epicondyle of Humerus

I: Palmar AponeurosisA: Wrist flexion

Q: How do you test for this muscle and why is it important?

Palmaris LongusTested:• With wrist slightly flexed• Oppose thumb and little

finger

Importance:

Used in tendon transfers (autografts)

Flexor Carpi Ulnaris O:Medial

Epicondyle of Humerus

I: Pisiform (carpal bone proximal row)

A: Flexion and Adduction of Wrist (ulnar deviation)

Wrist Flexor Palpation Video

• http://www.youtube.com/watch?v=ykB4YFPJ2ek&feature=related

Integrated Function of Wrist Flexors

• Assists in deceleration of wrist extensors• Assists in dynamic stabilization of the

wrist and hand• Flexor Carpi Radialis and Flexor Carpi

Ulnaris–Assists in deceleration of wrist abduction

• Flexor Digitorum Superficialis–Assists in deceleration of finger extension

Extensor Carpi Radialis Longus

O: Lateral Epicondyle of Humerus

I: Base of 2nd metacarpal

A: Extension of wrist

Abduction of wrist(radial deviation)

Extensor Carpi Radialis BrevisO: Lateral Epicondyle of

HumerusI: Base of 3rd

metacarpal on dorsal surface

A: Extension of wristAbduction of Wrist

Extensor Carpi UlnarisO: Lateral Epicondyle

of Humerus I: Base of 5th

metacarpal on dorsal surface

A: Extension of WristAdduction of Wrist

(ulnar deviation)

Integrated Function of Wrist Extensors• Assists in deceleration of wrist flexion• Assists in dynamic stabilization of the wrist

and hand• Extensor Carpi Radialis Brevis and Longus

–Assists in deceleration of wrist adduction

• Extensor Carpi Ulnaris– Assists in deceleration of wrist

abduction

Phalange Muscles• Finger flexors

– Flexor Digitorum Superficialis– Flexor Digitorum Profundus

• Thumb flexor– Flexor Pollicis Longus

• Finger extensors– Extensor Digitorum– Extensor Indicis– Extensor Digiti Minimi

• Thumb extensor– Extensor Pollicis Longus– Extensor Pollicis Brevis

These muscles assist inwrist actions

Carpal Tunnel Syndrome• Impingement or

compression of the median nerve

• Occurs from chronic swelling of the wrist flexor tendons

• The median nerve, which innervates the first three fingers and the thumb, can become impaired from pressure in the carpal tunnel in the wrist

Carpal Tunnel Syndrome• Causes

–Awkward hand postures–Long hours of repetitive typing–Repeated use of hand tools–Smoking-it may reduce blood flow to

median nerve–Wrist injuries –Development of a cyst or tumor in the

carpal tunnel– Common in assembly line workers, nail

technicians, data entry personnel, musicians

Carpal Tunnel Syndrome• Signs and Symptoms

– Pain, numbness, or tingling in the first three fingers and the thumb

– Increased pain with increased use of your hand, such as typing

– Night pain – Weak grip and tendency to drop objects

Carpal Tunnel Syndrome• Tests

– Tinel’s Sign: Tapping over the median nerve at the wrist may cause pain to shoot from the wrist to the hand

– Phalen’s Test: Pushing the back of your hands together for 60 seconds compresses the carpal tunnel and may cause pain

Carpal Tunnel Syndrome• Treatments

– Ergonomic aids: Split keyboards, keyboard trays, typing pads, cushioned mouse pads and wrist braces, may be used to improve wrist posture during typing

– Take frequent breaks when typing and always stop if there is tingling or pain

– Avoid sleeping on wrists– NSAID’s– Physical or Occupational Therapy– Carpal tunnel release surgery

Carpal Tunnel Syndrome• Exercises

– Contraindicated–Heavy

resistance training

–Excessive wrist flexion and extension

• What to do:–Focus on

flexibility!

Carpal Tunnel Syndrome• Stretch the following muscle groups

– Elbow Flexors– Wrist Flexors– Finger Flexors

• Extension exercises are key to recovery! It will help hold the carpal tunnel open

• Strengthen the following muscle groups– Elbow Extensors– Wrist Extensors– Finger Extensors– Finger Abductors