Hand Flashcards
How many bones are in the hand?
29 muscles, 19 bones, 19 articulations
What joints are in the hand?
CMC, MCP, IP
-thumbs of 1 IP joint
Fingers have PIP and DIP
What kind of joint is the CMC of the thumb?
saddle
What is the characteristic feature of a saddle joint?
each articular surface convex in one dimension and concave in other
The longitudinal diameter of articular surface of trapezium is what?
concave from palmar to dorsal to direction
The transverse surface of the trapezium is?
convex in ML direction
How many degrees of freedom does the CMC joint have?
2 degrees: abduction and adduction; flexion and extension
Abduction and adduction of the CMC joint occurs in what plane?
sagittal
Flexion and extension of the CMC joint occurs in what plane?
frontal
What is the axis of rotation for the CMC joint?
passes through the convex member of articulation
What does full extension of the CMC of the thumb stretch?
anterior oblique ligament (AOL), intermetacarpal ligament (IML) ad abductor pollicis musclw
What are the arthokinematics of abduction at the CMC joint?
anterior roll, posterior slide
What are the arthokinematics of adduction at the CMC joint?
posterior roll, anterior slide
What is primarily responsible for active rolling of articular surface of thumb metacarpal
abductor pollicis longus
What are the arthokinematics of flexion at the CMC joint?
roll and slide in medial direction (concvex on concave)
What are the arthokinematics of extension at the CMC joint?
roll and slide in lateral direction (concave on convex)
Where is the axis of rotation of the CMC of the thumb?
trapezium
Flexion of the CMC joint of thumb causes elongation and slack of what:
radio collateral ligament
anterior oblique ligament
Extension of the CMC joint of thumb causes elongation what:
anterior oblique ligament
What planes do flexion and extension of the MCP joints occur:
sagittal plane
What planes do abduction and adduction of the MCP joints occur:
frontal plane
What are the arthrokinematics of the MCP joint in flexion:
roll and slide in same direction (concave on convex)
What are the arthrokinematics of the MCP joint in extension:
roll and slide in same direction
What must be activated in MCP flexion?
flexor digitorum profundus
What is taut in MCP flexion?
dorsal capsule
radial collateral ligament
What is extension of the MCP controlled by?
coactivation of extensor digitorum and one of intrisinc muscles of finger
What is taut in MCP extension?
palmar plate taut
slack in radio collateral ligament
What are the arthokinematics of abduction at the MCP joint?
roll and slide in same direction
What are the arthokinematics of adduction at the MCP joint?
roll and slide in same direction
Abduction of the MCP joint is powered by what?
first dorsal interosseus muscle
What is taut and slack during abduction of the MCP joint?
taut: ulnar collateral ligament
slack: radio collateral ligament
What is the AOR of abduction?
AP direction through the head of metacarpal
What is the degree of freedom of IP joints?
one: flexion and extension
What muscles power flexion of the IP joints of thumbs?
- flexor pollicis longus
- flexor pollicis brevis
What is the AOR for flexion and extension of the IP joints?
AP direction through convex members of joints