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.)