Antebrachial Extensors Flashcards
Lister’s tubercle
- on dorsal distal radius
- pulley (changes muscle direction/angle) for extensor pollicis longus tendon
Carpals
- proximal: scaphoid, lunate, triquetrum, pisiform
- distal: trapezium, trapezoid, capitate, hamate
Distal Radioulnar Joint (DRUJ)
- synovial, pivot (uniaxial)
- pronation, supination
- supporting ligaments = volar and dorsal radioulnar ligaments
Radiocarpal Joint
- radius + scaphoid & lunate
- synovial, ellipsoid (biaxial)
- wrist flexion, extension, radial deviation, ulnar deviation
Midcarpal Joint
- interaction b/w proximal and distal carpal bones to perform global wrist and hand movements
- synovial, ellipsoid (biaxial)
- wrist flexion, extension, radial deviation, ulnar deviation, circumduction
Triangular Fibrocartilage Complex (TFCC)
- cushion b/w distal ulna and carpals
- stability on ulnar side of wrist
Carpometacarpal Joints (CMC)
- carpals + metacarpals
- gliding
- volar/dorsal gliding
Metacarpophalangeal Joints (MCP)
- metacarpals + phalanges
- synovial, ellipsoid (biaxial)
- finger flexion, extension, abduction, adduction
- flexion = volar gliding
- extension = dorsal gliding
Interphalangeal Joints (IP)
- b/w phalanges
- synovial, hinge (uniaxial)
- finger flexion, extension
- proximal (PIP) and distal (DIP)
- thumb only has 1 … IP
Carpometacarpal Joint (CMC) of Thumb
- trapezium + 1st metacarpal
- synovial, saddle (biaxial)
- thumb flexion, extension, abduction, adduction
- basilar joint
Arterial Supply
ulnar artery > common interosseous a. > splits into posterior and anterior interosseous arteries
- posterior interosseous a. runs through aperture of interosseous membrane
Intrinsic vs Extrinsic Muscles
- extrinsic = originate proximal to wrist, generate greater force
- intrinsic = contained entirely w/in hand, precise control
Superficial Layer of Extrinsic Extensor Muscles
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
Deep Layer of Extrinsic Extensor Muscles
- extensor indicis
- supinator
Outcropping Layer of Extrinsic Extensor Muscles
- abductor pollicis longus
- extensor pollicis longus
- extensor pollicis brevis
Tennis Elbow
- ECRL and ECRB
- inflammation of periosteium at lateral epicondyle
- pain w/ gripping, opening a heavy door, lifting a glass
- lateral epicondylitis = acute, inflammation, hot, swelling
- epicondylosis = chronic, degeneration, no swelling
Rule of 2’s
- wrist flexors = FCR, FCU
- wrist extensors = ECRL, ECRB, ECU
- radial deviators = FCR, ECRL, ECRB
- ulnar deviators = FCU, ECU
Anatomical Snuffbox
boundaries formed by tendons of abductor pollicis longus, extensor pollicis brevis, and extensor pollicis longus
Extensor Retinaculum
thick sheath that covers and keeps extensor tendons in place and separates them into 6 compartments
6 Dorsal Compartments of the Wrist
1 - APL, EPB
2 - ECRL, ECRB
3 - EPL
4 - ED, EI
5 - EDM
6 - ECU
De Quervain’s Tenosynovitis
- “texting thumb”
- cumulative trauma disorder of tendons of 1st dorsal compartment (APL, EPB)
- common w/ new mothers, repetitive keystrokes, gaming
Tenodesis
- passive finger flexion created by active wrist extension
- functional grip for individuals w/ paralysis of finger flexors
- ex: SCI at C6 level
Distal Radius Fracture
- smith’s fracture = volar displacement of distal bone, inward
- colles’ fracture = dorsal displacement of distal bone, outward
Scaphoid Fracture
- most commonly fractured carpal bone
- from a FOOSH injury (fall on outstretched hand)
- can lead to a necrotic proximal fragment due to loss of blood supply from radial artery
