Wrist and Extrinsic Hand Flashcards
Intrinsic vs. Extrinsic
Intrinsic: Hand muscles originate AND insert within the hand.
Extrinsic: Hand muscles originate in the ARM, and insert in the hand. (Involve the wrist, since they cross it.)
Wrist Joint
- Called the “Radiocarpal Joint”; at distal end of radius
- Includes the Carpal Bones (Scaphoid, Lunate and Triquetrum)
- Condyloid Joint
- Biaxial (flex/extend in sagittal, ulnar/radial deviation in frontal)
Bony Landmarks of the Hand/Wrist
- Radial Styloid (bump in wrist below base of thumb)
- Pisiform Bone (above wrist, at base of ulnar side of hand)
- Ulnar Styloid (bump in wrist below base of pinky)
Order of BONES in Hand (Types)
From Wrist to Fingertips:
• Carpal Bones
• Metacarpals
• Phalanges
Order of Wrist/Hand JOINTS
From Wrist to Fingertips: • Radiocarpal Joint (wrist) • Carpometacarpal Joint (CMC) • Metacarpophalangeal Joint (MCP) • Proximal Interphalangeal Joint (PIP) • Distal Interphalangeal Joint (DIP)
Carpal Bones (Proximal Row)
(From Radial to Ulnar) • Scaphoid • Lunate • Triquetrum • Pisiform (“So Long To Pinky”) – Pisiform=Pinky side
Carpal Bones (Distal Row)
(From Ulnar to Radial) • Trapezium • Trapezoid • Capitate • Hamate (“Here Comes The Thumb”) – Trapezium=Thumb side
Motion at Radiocarpal Joint
(Note: there is no “normal”-varies by person, and even by which hand!) • Flexion = 0-60˚ • Extension = 0-60˚ • Radial Deviation = 0-20˚ • Ulnar Deviation = 0-30˚
Circumduction
Wrist’s ability to make a circular movement. This is NOT an independent motion of the wrist, but a COMBINATION of all four movements.
Wrist Flexors
All originate at the medial epicondyle.
• Flexor Carpi Ulnaris
• Flexor Carpi Radialis
• Palmaris Longus (missing in 21% of ppl)
Wrist Extensors
All originate at the lateral epicondyle.
• Extensor Carpi Radialis Longus
• Extensor Carpi Radialis Brevis
• Extensor Carpi Ulnaris
Wrist Radial Deviator Muscles
- Flexor Carpi Radialis
* Extensor Carpi Radialis Longus
Innervations of Wrist
1) Radial Nerve (muscles on dorsal surface)
2) Median Nerve (muscles on thumb side)
3) Ulnar Nerve (muscles on ulnar side)
Main Ligaments of the Wrist
1) Radial Collateral Ligament (attaches from radius to scaphoid and trapezium)*
2) Ulnar Collateral Ligament (attaches from ulna to pisiform and triquetrum)*
• *Above 2 provide LATERAL and MEDIAL support.
3) Palmar Radiocarpal Ligament (tough lig that limits wrist extension. Attaches from anterior surface of distal radius and ulna to the proximal carpal bones; prone to sprain)
4) Dorsal Radiocarpal Ligament (Less dense/strong as palmar, limits flexion. Attaches posterior surface of distal radius to proximal carpal bones)
Extrinsic Motions of the Hand
(motions caused by extrinsic muscles) • Finger Flexion • Finger Extension • Thumb Radial ABduction • Thumb Flexion
Main Ligaments of the Hand
*All hold muscles together/bound to the wrist during motions.
1) Flexor Retinaculum Ligament (Band of connective tissue crossing wrist/hand on anterior side. Contains finger flexor tendons during wrist flexion.)
2) Extensor Retinaculum Ligament (Similar connective tissue crossing wrist on posterior side. Contains extensor finger tendons close to hand during wrist extension.)
3) Transverse Carpal Ligament/Flexor Retinaculum (Forms carpal tunnel.)
4) Palmar Carpal Ligament (More proximal and superficial.)
Extrinsic Muscles of the Hand
1) Extensor Digitorum (extends all finger joints)
2) Extensor Digiti Minimi (extends pinky)
3) Extensor Indicis (extends all joints of index finger)
4) Flexor Digitorum Superficialis (flexes PIP joints)
5) Flexor Digitorum Profundus (flexes all finger joints, but DIP would not flex without it)
Joints of the Thumb
(Proximal to Distal):
1) Carpometacarpal (CMC): trapezium articulates with 1st metacarpal. Has 3 degrees of freedom/6 motions (flex, ext, aBd, aDd, opposition, reposition)
2) Metacarpophalangeal (MCP): flex/ext
3) Interphalangeal (IP): flex/ext
Extrinsic Muscles of the Thumb
1) Extensor Pollicis Brevis: extends CMC and MCP joints
2) Extensor Pollicis Longus: extends all joints of thumb
Anatomical Snuff Box
Triangle on radial side of hand between wrist and thumb. Formed by:
• Abductor Pollicis Longus
• Extensor Pollicis Brevis
• Extensor Pollicis Longus
Innervations of the Thumb
1) Radial Nerve (Extensors and abductor pollicis longus)
2) Median Nerve (Flexor pollicis longus)
Innervations of the Fingers
1) Radial Nerve (Extensors)
2) Median Nerve (Flexor Digitorum Superficialis)
3) Median and Ulnar Nerves (Flexor Digitorum Profundus)
Conditions of Extrinsic Wrist and Hand (List)
1) de Quervain’s Disease /Washer woman’s syndrome
2) Distal Radial Fracture
3) Triangular Fibrocartilage Complex Tear
4) Fractures of Scaphoid
deQuervain’s Disease
- Also called Tenosynovitis or “Washer Woman’s Syndrome”
- Inflammation of Tendon Sheath in wrist
- Affects APL, EPB, EPL
- Caused by repetitive movements of wrist and thumb
- Doc uses “Finkelstein Test” to diagnose (see if pain when flexing thumb in ulnar deviation)
Finkelstein Test
Used to determine if someone has Tenosynovitis (deQuervain’s Disease). Checks for pain when thumb is put into flexion over palm while hand ulnar deviates.
Distal Radial Fracture
Caused by fall on outstretched hand (FOOSH), with wrist extended. (Also called a Colle’s Fracture.)
Colle’s Fracture vs. Smith’s Fracture
Colle’s Fracture = when wrist is extended (dorsal fracture of radius)
Smith’s Fracture = when wrist is flexed (ventral fracture of radius) *Less common.
Goniometry of Wrist
Flex/Extend:
• Use ulnar side of hand to eliminate thumb.
• Palpate to find bony landmarks.
• Line goni to arm/ulna bone and metacarpal of hand.
• Fulcrum at ulnar styloid.
Deviations:
• Center goni over carpal bones (dorsal)
• Use middle finger tendon (extensor dig. long.)
• Ignore fingers! Only use metacarpals!
MMT of Wrist
Flex/Extend:
• One hand holds forearm for support, other is at palm of hand (distal to wrist)
Deviations:
• Move to ulnar/radial sides to do deviations.
• Go inside the thumb to eliminate it from test
Avascular Necrosis (AVN)
Death of bone tissue.
(A scaphoid fracture can cause AVN depending on the location of the fracture within the scaphoid bone. Carpal bones do not have good blood supply because of the articular cartilage they are covered in.)
MCP vs. PIP vs. DIP
MCP = metacarpophalangeal (most proximal joint of finger; the knuckles)
PIP = proximal interphalangeal (middle joint of finger)
DIP = distal interphalangeal (finger tip joint)
Factors Affecting Wrist ROM
- Ligament tightness
- Ligament laxity
- Muscle mass
- Articulating surface lubrication
Wrist ROM needed for most ADLs
40˚ of combined flexion/extension, and 40˚ of composite radial/ulnar deviation
CMC Joint of Thumb
- Saddle joint-provides mobility in all directions
- Formed by trapezium bone proximally and first metacarpal bone distally
- Facilitates opposition of the thumb
Thumb Flexion
Movement of thumb toward and across palm (side to side motion)
Thumb Extension
Movement of thumb away from radial side of hand (out to side in plane of hand)
Thumb ABduction
Movement of thumb away from front of palm (out of plane of the hand)
Thumb ADduction
Movement of thumb toward front of palm (from out of plane of the hand)
Oppostion/Reposition
Opposition: Movement of thumb to touch each finger
Reposition: Movement of thumb back to neutral
Importance of UE when ambulating with crutches, walker, or cane
ALL JOINTS AND MUSCLES of the UE are used when ambulating with crutches, walker, or cane.
Wrist weight-bearing ability
Wrist is made to withstand large loads (such as using jackhammer, hitting golf ball, hammering). Ex: a grasping activity using only 2-lb weight causes 35 lb of force on the wrist!
Wrist serves kinetic function in transmitting forces from the forearm to the hand and back to forearm.
Driving as it relates to UEs
Activity of driving requires strength and coordination of ALL THE JOINTS of the UEs.
Triangular Fibrocartilage Complex Tear
Tear of the TFCC after a direct compressive force (such as FOOSH).
• Often seen in conjunction with distal radius fracture
• Can also happen with degenerative changes due to aging/wear-and-tear
• Ulnar wrist pain with forearm rotation, ulnar deviation and gripping
• May also have swelling and crepitus
• Diagnosed by palpation/tenderness; or “piano key”—protruding ulna head that springs back when pressed.
• Conservative treatment is splint, ergonomics, activity modification.
• May require arthroscopic surgery to debride/repair the tear.
Fractures of the Scaphoid
- Most common carpal fracture, 60% of them
- Males 15-30 yo
- Extreme hyperextension of wrist combined with radial deviation (ie: sports-related FOOSH)
- Pain, swelling in snuff box area
- Scaphoid bone has a waist, distal pole, and proximal pole. Fractures categorized by location on bone.
- Scaphoid has poor blood supply due to cartilage covering; causes greater chance of avascular necrosis (AVN).
- Can be seen in well-taken x-ray, but bone scan/MRI usually required
- Requires cast based on type of fracture.
- Proximal waist fracture requires surgery/screw before cast
- Client goes to hand therapy and wears removable wrist/thumb splint after.
Triangular Fibrocartilage Complex (TFCC)
Also known as ulnocarpal complex.
• Includes articular disc of wrist
• Radial and Ulnar collateral ligaments, providing lateral and medial support to wrist.
• Major stabilizer of the distal radioulnar joint (DRUJ)
• Tears after direct compressive force (like FOOSH)
Flexor Carpi Ulnaris (FCU)
- Prime mover in wrist flexion/ulnar deviation
- Also weak flexor of elbow
- Only wrist muscle with attachment to a carpal bone
- Considered strongest wrist flexor, and used for sustained power grip (ax, hammer)
Muscles of Wrist
There are 6 muscles primarily responsible for wrist movement, but no single muscle moves the wrist in one plane! Pairs of muscles must always contract together to cause the motions.
Flexor Digitorum Superficialis (FDS)
- Divides into 4 tendons on palmar aspect of wrist/hand to insert on each of 4 fingers on sides of middle phalanx
- One of only 2 muscles that produce flexion of all 4 fingers
- Vital in any gripping activity
- Can flex PIP joint without flexing DIP
- Assists in wrist flexion during finger flexion
Flexor Digitorum Profundus (FDP)
- Primary flexor of the fingers
- Up to 50% stronger than FDS, but works with it to flex 4 fingers
- Only muscle that produces flexion of DIP joints of all 4 fingers
- Also flexes PIP and MCP finger joints and assists with wrist flexion
Flexor Pollicis Longus (FPL)
- Prime mover of thumb flexion for all 3 joints
- Palmar in wrist; assists with wrist flexion
- Vital role in pinching/gripping
Abductor Pollicis Longus (APL)
- Abducts thumb at CMC joint
* Forms lateral border of snuff box
Extensor Pollicis Longus (EPL)
- Extends IP of thumb
- Aids in extension of thumb at MCP/CMC
- Assists with wrist extension/radial deviation
- Also thumb adductor due to dorsal location around distal radius
Extensor Pollicis Brevis (EPB)
- Extends thumb at MCP
- Shares sheath with APL, so has same actions (Abducts CMC)
- Forms lateral border of snuff box with APL
Extensor Digitorum Communis (EDC)
- Extends all joints of 4 fingers
- Only common extensor of fingers
- Assists with wrist extension
- Tendons interconnected at MCP joints by juncturae tendinae
Juncturae Tendinae
Fibrous bands that interconnect extensor tendons of all 4 fingers at the MCP joints. Impede individual finger extension, but they provide stabilizing forces to MCP joints while fingers are flexed during forceful gripping.
Extensor Digiti Minimi (EDM)
- Allows extension of MCP joint of pinky
* Located on ulnar side of EDC and acts to extend/abduct PIP and DIP of pinky
Extensor Indicis Proprius (EIP)
- Allows independent extension of MCP of index finger, and extends PIP/DIP
- Commonly called the “Pointing Muscle”
Nerve Roots Supplying Joints/Muscles of Wrist and Hand
C6-C8, and T1 (Peripheral nerves radial, median, and ulnar)
Innervation for Muscles on Posterior Surface of Wrist/Hand
Radial Nerve
Innervation for Muscles on Thumb Side of Wrist/Hand
Median Nerve
Innervation for Muscles on Ulnar Side of Wrist/Hand
Ulnar Nerve
Innervation of Flexor Digitorum Profundus
Both Ulnar and Median nerves
Extrinsic Tendons of Hand
- More susceptible to inflammation due to their length and space limitations at wrist.
- Pass through carpal tunnel
- Some are covered (and may share) in Synovial Sheath lined with synovial fluid
“Pulleys”
Annular, oblique and cruciate fibers that secure flexor tendons at the fingers.
• Prevent bowstringing of tendons during finger flexion/gripping
Flexor vs. Extensor Tendons
Flexor tendons: Cord-like for strength
Extensor tendons: Flatter, weaker; no synovial sheath. Do not have to work against resistance.
• Because of their superficiality, tendons are prone to laceration. Must be surgically repaired if completely lacerated.
Interosseous Ligaments of Wrist
- Intrinsic ligaments of wrist.
- Stabilize individual carpal bones to each other
- Considered strongest in wrist, but are less rigid; allow larger loads of force when fallingon outstretched arm.
Carpal Bones (in proximal-to-distal order)
Scaphoid Lunate Triquetrum Pisiform Trapezium Trapezoid Capitate Hamate
