ASHT - Hand Anatomy and Kinesiology Flashcards
what are Grayson’s and Clelands ligaments?
Tether skin to bone and deep fascial layers. Prevent excessive skin mobility and improve grip. Grayson is anterior and Cleland is posterior to digital neurovascular bundle
what is the anterior oblique ligament? (AOL)
The primary stabilizer of the 1st CMC joint. Helps prevent dorsal subluxation of metacarpal base. Taut in AB, ext, opposition. Important to know it becomes lax with OA. Also called beak ligament
what MP joint position are collateral ligaments tight?
MP flexion - resists radial/ulnar deviation
What do MP collateral ligaments do?
limit lateral movement. 2 components. 1. true/proper-taut in flexion, loose in extension Allows for AB AD. 2. Accessory - taut in extension, slack in flexion stabilizes digital flexors
What does MP volar plate do?
attaches to metacarpal head and proximal phalanx, limits hyperextension of the joint (allows more at MP than PIP)
What are thumb stabilizing ligaments? (2)
Stabilizes thumb with AB AD and varus/valgus stressRCL - axial tip pressure like pushing a button. UCL - important for power pinch and grasp.
PIP joint stabilizers by dorsal, lateral, volar
Dorsal: central slip, triangular ligament, lateral band, ORL. Lateral: collateral ligaments Volar: volar plate, FDP tendon FDS tendon
Checkrein ligaments
proximal extension from PIP volar plate - adds stability and allows for blood vessel passage. distally anchored to middle phalanx
what provides stability to DIP joint? (5)
terminal tendon, FDP, volar plate, ORL, collateral ligaments
Campers Chiasm
area where the FDS splits just proximal to the PIP, where the FDS tendons rotate 180° and insert deep to the FDP tendon
Primary extender of thumb CMC MP IP joint
EPL
APL Abductor Pollicis longus
extrinsic m. localted in posterior compartment and innervated by PIN/radial n.
Anatomical snuff box
medial border - EPL, lateral border - APL, EPB, Floor - scaphoid, trapezium
what muscles are the “thenars?”
APB, FPB, OP “AFO” (FAO schwartz) intrinsic
Fun facts about Dorsal Interossei
DAB (4) 2 go to long finger, bipennate. superficial inserts to prox phalanx and is strong AB, deep works with PI to create lateral bands and for MP flex + IP extension. Deep to sagital bands
Fun facts about Palmar Interossei
PAD (3) none to middle finger. no bony insertion, weaker, ADD and weak MP flexion. All unipennate
Fun facts about Lumbricals
1+2 unipennate - prehension 3+4 bipennate power grasp. With lumbricals active, FDP relaxes to allow for PIP extension. Median and ulnar nerve bc they follow the FDP tendons. “work horse of extensor mechanism”
Palmaris Brevis
steadies skin of palm, assists with grip. ulnar nerve. O: flexor retinaculum, palmar aponeurosis I: skin of palm into dermis
Digital Arteries
Ulnar artery through Guyon’s canal to superficial palmar arch - most bloody supply to hand. Radial artery lateral to FCR to deep palmar arch. Blood supply to thumb and radial index.
what are 2 parts of flexor sheath?
- Membranous part - synovial tube. Surrounds tendons and includes radial and ulnar bursa (FD/FDP) 2. retinacular tissue - pulley system
what happens with loss of pulleys?
decreased flexion, decreased grip strength, bowstringing
what are Vincula?
Connective tissue that contains vessels. Direct blood supply to flexor tendons. (tendons also receive nutrition from synovium)
Sagittal Bands? (4)
@ MP joint. stabilizes extensor hood at MP joint. Centralizes EDC tendon over MP joint. COnnect extensor hood to volar plate. Prevent bowstringing of EDC during extension.
Central Slip?
EDC tendon continues as 3 slips - central slip and 2 lateral bands. Function PIP extension
