Transcript The Wrist and Hand Joints

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
Pronators
Supinators
• Pronator Teres • Biceps Brachii
• Pronator
• Supinator
Quadratus
• Brachioradialis
• Brachioradialis
Pronator Teres
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 Quadratus
Deep Anterior Muscle
O: Distal anterior ulna
I: Distal anterior radius
A: Forearm Pronation
Integrated Function:
Assists in deceleration of
supination of radioulnar
joint
Supinator
Deep Posterior Muscle
O: Lateral Epicondyle of
Humerus
I: Wraps around proximal
radius
A: Supination of Radioulnar
Joint
Integrated 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
These muscles
do not cause
finger
movements
• Superficial Wrist extensors
–Extensor Carpi Radialis Longus
–Extensor Carpi Radialis Brevis
–Extensor Carpi Ulnaris
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 Aponeurosis
A: Wrist flexion
Q: How do you test for this
muscle and why is it
important?
Palmaris Longus
Tested:
• 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=ykB4YFPJ2
ek&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 Brevis
O: Lateral Epicondyle of
Humerus
I: Base of 3rd
metacarpal on dorsal
surface
A: Extension of wrist
Abduction of Wrist
Extensor Carpi Ulnaris
O: Lateral Epicondyle
of Humerus
I: Base of 5th
metacarpal on
dorsal surface
A: Extension of Wrist
Adduction 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 in
wrist 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