forearm, wrist and hand. functions of the forearm, wrist, and hand forearm – enables the hand to...
TRANSCRIPT
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