Final - Wrist And Hand Flashcards
What is the keystone of the wrist?
Capitate
Which carpal row is unstable?
Proximal, most with the radius
Which carpal is the main weight bearing the most fractured
Scaphoid
Which carpal is most unstable and dislocates anteriorly?
Lunate
Where is the longitudinal arch of the hand and what is the keystone?
- follow 2nd and 3rd rays
- keystone: 2nd and 3rd MCPs
Where is the distal transverse arch of the hand and what is the keystone?
- passes through MCP joints
- keystone: 2nd and 3rd MCPs
Where is the proximal transverse arch of the hand and what is the keystone?
- carpal tunnel
- keystone: capitate
Which arch of the hand is static and rigid? Which is mobile?
Proximal transverse
Distal transverse
What makes the bottom and top of the carpal tunnel?
Bottom: carpal gutter
Top: flexor retinaculum
What are the contents of the carpal tunnel?
- flexor tendons
- median nerves
- no vessels
When is the carpal tunnel compressed?
At high degrees of flexion and extension
What are the borders of the tunnel of guy on (ulnar canal?)
- pisiform, hamate, pisohamate ligament, deep flexor retinaculum ad hypothenar muscles
What is the contents of the tunnel of guy on (ulnar canal)?
- ulnar nerve and artery
__% of axial loading is through scaphoid and lunate to the radius. __% of axial loading is through the articulation at the ulnocarpal space
80
20
When the wrist is extended the compressive force on the thenars (FOOSH) increases __x through the scaphoid
4x
What does the TFCC stand for, where is it and
Triangular fibrocartilage complex
Fibrocartilage disc at the distal end of the ulna that articulates with the lunate and triquetrum
What is the primary function of the TFCC?
- bind the distal ends of the radius and ulna
What is the primary stabilizer of the distal radioulnar joint?
TFCC
*helps transfer 20% of the compressive forces form the hand to the forearm
The wrist joint is convex on concave meaning is has (same/opposite) roll and slide?
Opposite
How much flexion occurs at the wrist? Which direction is the roll and slide?
70-85
Palmer roll, dorsal slide
How much extension occurs at the wrist? Which direction is the roll and slide?
60-75
Dorsal roll, palmer slide
Does the distal carpal row move more with flexion or extension? The proximal row?
Distal = flexion Proximal = extension
How much ulnar deviation is there? What is the roll and slide in the scaphoid, lunate and triquetrum?
35-40 degrees
- ulnar roll, radial slide
How much radial deviation is there? What is the roll and slide in the scaphoid, lunate and triquetrum
15-20 degrees
- roll radially and slide ulnarly
What is the min function of the extensors?
To position and stabilize wrist during finger flexion
*max grip strength at 30-35 wrist extension
Which is stronger, wrist extensors or flexors?
Flexors
What is the functional position of the hand?
- wrist 20-30 degrees extension
- fingers 45 degrees of MCP and 15 degree PIP/DIP flexion
- thumb in 45 degrees abduction
The MCP joints are __axial and concave on convex meaning they have (same/opposite) roll/slide
Biaxial
- same roll and slide
What is the function of the valor plate (palmer plate). 2 things
- strengthens the structure of the MCP and IP joint
- limits extension
Is there more passive or active motion available at the MCP joints?
Passive
*allows fingers to conform to shape of held objects
The IP joint is __axial
Uniaxial
What type of joint is the carpometacarpal joint of the thumb?
Saddle joint (allows full opposition)
The CMC joint for adduction/ abduction is convex on concave meaning the roll and slide occur in (same/opposite) directions? what are they for thumb abduction and adduction?
Opposite
Abduction: roll palmarly, slide dorsally
Adduction: roll dorsally, slide palmarly
The CMC joint for flexion extension is concave on convex meaning roll and slide occur in (same/opposite) direction
Same
Flexion: roll and slide medially
Extension: roll and slide laterally
