Hand Flashcards
Ulnar tilt is ______ degrees
25
Palmar tilt is _____ degrees
10
What is ulnar variance
Difference between lengths of radius and ulna
What is considered an abnormal ulnar variance?
Difference between radius and ulna length of more than 1 mm
What does “ulnar positive” mean?
Ulna is longer than radius
What does “ulnar negative” mean?
Distal ulna is shorter than the radius
Pronation is functional ______ of radius
Shortening
Supination = functional ______ of radius
Lengthening
Which is the most unstable carpal bone?
Lunate
What carpal bone has most ulnar position?
Triquetrum
Which carpal bone is a sesamoid bone?
Pisiform
Which is the largest carpal bone?
Capitate
Which carpal bone articulates with the first MC?
Trapezium
Which carpal bone articulates with the second MC?
Trapezoid
Describe the scaphoid.
Elongated shape.
Which ligament creates the carpal tunnel?
Transverse carpal ligament.
What is the function of the carpal tunnel?
- Passageway for mediaun nerve/tendons of extrinsic finger flexor
- Prevents bowstringing of tendons, especially during gripping in wrist flexion
Describe radiocarpal joint.
- Concave radius/articular disk
- Convex scaphoid/lunate
Describe the medial compartment of the midcarpal joint.
Convex capitate/hamate, concave scaphoid/lunate/triquetrum
Describe lateral compartment of midcarpal joint.
Concave trapezium/trapezoid, convex scaphoid.
TFCC Joint
Ulnocarpal!!!!!!
Maintains alignment/disperses forces
Extrinsic
Normal amount of wrist flexion
0-75/80
Normal wrist extension
0-65/70
Normal ulnar deviation
0-35/40
Normal radial deviation
0-15/20
Extension occurs with…
Radial deviation
Flexion occurs with
Ulnar deviation
AOR of wrist flex/ext
Capitate
Arthrokinematics of radiocarpal joint
Convex carpal on concave radius– roll and glide in opposite directions.
Wrist extension arthrokinematics
Anterior slide, posterior roll
Wrist flexion arthrokinematics
Posterior slide, anterior roll
Ulnar deviation arthrokinematics
Roll towards midline, slide away
Radial deviation arthrokinematics
Roll laterally, slide medially
Primary wrist extensors
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
What two actions do long. Finger flexor create?
Finger flexion and wrist flexion– counteracted by extensors which cause wrist extension in grip (ECRB, etc)
How much wrist extension occurs in maximal effort grip?
30 degrees of extension.
Primary wrist flexors
Flexor carpi ulnaris
Flexor carpi radialis
Palmaris longus
Radial deviators
ECRL ECRB EPL EPB FCR ABL FPL
Ulnar deviators
ECU FCU FDP FDS ED
Radial deviators are innervated by which nerve(s)?
Radial
Ulnar deviators are innervated by which nerve(s)?
Median and ulnar nerves
First metacarpal rotated
90 degrees medially–required orientation for prehension
First metacarpal positoned anterior, allows
Thumb to position itself at fingers for prehension.
Transverse arches of the hand
Proximal
Distal
What is the proximal transverse arch formed by?
Distal row of carpal bones
What is the keystone of the proximal transverse arch?
Capitate
Which hand arch is mobile?
Distal transverse arch
Distal transverse arch is formed by _____ joints
MCP
Which hand arch is rigid?
Proximal transverse arch
Distal transverse arch keystone structure
Second and third MCPs
–mobile at 1,4,5 MCP
Which CMC joints are stabile
2/3
Which cmc joints are mobile
4/5
-look at when you make a fist– four and five flex much more than 2/3.
Why is the first cmc joint capsule loose?
Allows movement– reinforced by musculature/ligaments
Which motions comprise opposition?
Abduction
Flexion w/ internal rotation
Fingers have _____ metacarpals and _____ proximal phalanges
Convex metacarpals
Concave proximal phalanges
ROM for first mcp compared to fifth mcp
First = 90 degrees Fifth = 110/115
Amount of MCP abd/add
20 degrees
How many DOF does the thumb have?
One!! Abd/add are accessory motions.
Arthrokinematics of IP joints— ____ distally, ____ proximally
Concave distally
Convex proximally
Arthrokinematics of IPS
ROLL AND SLIDE IN SAME DIRECTION
Extrinsic hand muscles
Digit flexors
Digit extensors
Thumb extensors
Hand intrinsics
Thenar eminence Hypothenar eminence Lumbricals Interossei Adductor pollicis
Extrinsic flexors
FDP
FDS
FPL
What are fibrous digital sheaths?
Protective tunnels where extrinsic flexor tendons travel
Increased force to isolate PIP flexion requires…
Stabilization from proximal stabilizers (ED/wrist extensors)
Isolated contraction of MCP hyperextension
MCP hyperextension (Requires cont from intrinsics to extend PIP/DIP joints)
Extrinsic extensors
Extensor digitorum
Extensor indicis
Extensor DM
“Backbone” of extensor mechanism
Central band– attaches to dorsal base of middle phalanx
Lateral bands
- Diverge from central band
- Distally fuse to terminal tendon
- Attaches to distal phalanx
What is the dorsal hood?
Forms a sling around base of prox phalanx
What is extrinsic plus position?
MCP extension, IP flexion
What is intrinsic plus position?
MCP flexion, IP extension
Hand deformity of RA…
- FPL
- Palmar plate
- Ligaments
- CMC joint
- EPL
- Intrinsic muscles
FPL taught Stretched EPL Overstretched palmar plate at MCP joint Ruptured proximal ligaments (central band, slipped lateral band) Dislocated CMC joint Contracted intrinsic muscles