6) Thumb joints Flashcards
1st Carpometacarpal Joint
Saddle, simple, synovial,multiaxail
1st Carpometacarpal Joint
Articular surface
See file
1st Carpometacarpal Joint
Joint capsule
See file
1st Carpometacarpal Joint
Ligaments
Radial carpometacarpal ligament
Anterior oblique ligament
Posterior oblique ligament
Radial carpometacarpal ligament
Attachments:
Passes between adjacent lateral surfaces of trapezium and 1st metacarpal
Prevents lateral displacement of metacarpal on trapezium
Anterior oblique ligament
Attachments
Anterior trapezium to medial side of 1st metacarpal
Taut extension of thumb
Posterior oblique ligament
Attachments
Posterior surface of trapezium to medial side of 1st metacarpal
Taut in flexion
Stability
Carpometacarpal
Tone of muscle
Tendons
Shape of articular surface + looseness = mobile
Movements
Carpometacarpal
Flexion
Extension
Abduction
Opposition
Metacarpophalangeal
Condyloid, simple, synovial, multiaxail
Metacarpophalangeal
Articular surface
See file
Metacarpophalangeal
Joint capsule
See file
Metacarpophalangeal
Synovial membrane
Lines all non-articular surfaces of joint present anterior and posterior recesses when joint is extended
Metacarpophalangeal
Ligaments
Palmar ligament
Collateral ligament
Palmar ligament
Metacarpophalangeal
Dense fibrocartilaginous pad increases phalangeal articular surface anteriorly
Anterior surface base of proximal phalanx
Contains x2 sesamoid bones attracted
Limits extension
Collateral ligament
Metacarpalphalangeal
V strong, fan out proximal to distal
Attachments:
Proximally to tubercle and adjacent depression on side of metacarpal head ➖➖➖➖ palmar aspect side of base of proximal phalanx
Taut in flexion
Stability
Metacarpophalangeal
Collateral ligament
Tendons flexor, extensor pollicis longus
Movement
Metacarpophalangeal
Flexion Extension Abduction Adduction Opposition
Interphalangeal
Hinge,simple,synovial, uniaxail
Interphalangeal
Collateral ligament
Attachments:
Sides of head of proximal phalanx➖➖➖ palmar aspect base of distal phalanx
Blend lateral palmar ligament
Limit flexion
Interphalangeal
Palmar ligament
Fibrocartilaginous plate attached to anterior margin of base of distal phalanx
Limit extension
Interphalangeal
Stability
Palmar ligament
collateral ligament
Interphalangeal
Movement
Flexion
Extension
Interphalangeal
Articular surfaces
See file
Interphalangeal
Joint capsule
See file
Interphalangeal
Ligaments
Collateral
Palmar
Thumb grips
Percision grips— object is held between pads of digits
Rotation of CMC, MCP joints of thumb and MCP joint of fingers using intrinsic muscles of the hand and flexor digitorum superficialis, profundus and pollicis longissumus
1) Pincer: terminal opposition
2) Pinch: subterminal opposition
3) Key: subtermino-lateral opposition
Power grips—- used when considerable power is required using long flexors and extensors partly fixing the wrist and gripping the object
1) Palmar
2) Hook
3) Span
Dexterity
Achieved through a coordinated mix of precision and power through the available ROM
Skill in performance movements
Terminal opposition
Pincer grip
Most precise
Tips of pads or or edges of the nails
Subterminal opposition
Pinch grip
Most common
Palmar surfaces of thumb and finger
Subtermino-lateral opposition
Key grip
Less fine but strong grip
Pad of thumb presses against the side of any of the phalanges of fingers
when the distal phalanx of the index finger is lost it can replace terminal and sub terminal opposition
Palmar grip
Most powerful grip
Thumb acts as a buttress and the fingers wrap around the object
The volume of the object determines the strength of grip which is greatest when the tips of the index finger and thumb can still touch
Hook grip
The object is held firmly between the palm and flexed fingers
span grip
Abducted fingers and thumb in addition to the palm in order to grip circular objects e.g. Jar lids
