elbow, wrist, hand Flashcards
in the frontal plane, how much valgus is there?
6 degrees
in the sagittal plane, how much anterior rotation is there?
30 degrees
what kind of joint is the humeroulnar
hinge
how is the humeroulnar joint formed
- concave trochlear notch of ulna
- convex trcohlea of humerus
how does the humeroulnar joint glide
in the same direction
what is the carrying angle of males and females
M: 11-14
F: 13-16
how is the humeroradial joint formed
- convex capitulum of humerus
- concave head of radius
how does the humeroradial joint glide
in the same direction for flexion and extension
which motions does the humeroradial joint do
- flex/ext
- rotation of radius
which motions does the humeroulnar joint do
flex ext
what is the elbow capsule
- thin, but strong
- does not respond well to injury or immobilization
- forms thick scar tissue resulting in flexion contractures
describe the ulnar (medial) collateral ligament
- triangular shaped
- medial epicondyle to coronoid process and olencarnon
- 3 components: anterior, posterior, transverse/oblique
- provides stability against valgus stress
- important role between 20-130 degrees of motion
describe the anterior band of the ulnar (medial) collateral ligament
- strongest and stiffest elbow collateral lig
- becomes taught in terminal extension
- stabilizes elbow against valgus stress between 20-120 degrees
- secondary restraint at end range flexion beyond 120
describe the posterior band of the ulnar (medial) collateral lig
- weakest band
- taught beyond 55 of elbow flexion
- secondary restraint to valgus stress at lesser degrees of flexion
- an equal co-restraint with anterior band at terminal flexion (especially in overhead athlete in counteracting valgus stresses)
describe the transverse/oblique band of the ulnar (medial) collateral lig
- originates and inserts on ulna
- little role in elbow stablity
- deepends socket for trochlea
describe ulnar collateral lig injury
- most commonly anterior band ruptured
- varied repair and reconstruction techniques
- autograft of palmaris longus
describe the radial (lateral) collateral lig
- fan shaped
- lateral epicondyle and blends with annular lig
- consistent tension throughout arc of flexion
- restraint against varus load at elbow
- also primary restraint again posterolateral instability
what is posterolateral instability
- of the radial head
- if you distrupt radial/lateral collateral ligament then the radial head can sublux out of annular ligament in a postlat direction
describe the annular ligament
- provides 80% of the articular surface of humeral radial joint
- stabilizes radial head
- maintains relationship of radial head with ulna
- forms prox radioulnar joint
- permits pronation/sup
desribe osteokinematics of pronation
- radial head convex
- radial notch on ulna concave
- roll and glide of convex radius on concave ulna
- radial head rolls and glides in OPPOSITE direction
-radial head rolls ant and glides post
desribe osteokinematics of supination
- roll and glide of convex radius and concave ulna
- radial head rolls and glides in OPPOSITE direction
-radial head rolls post and glides ant
what kind of joint configuration is the distal radioulnar joint
ovoid
how is the distal radioulnar joint formed
- head of ulna convex
- ulnar notch on radius concave
-radius moving on ulna:
convex= roll and glide in same direction
what are the functions in conjunction with PRUJ
pron/sup
- occur simultaenously at both prox and distal radioulnar joints
- also requires rotation of radius at humeroradial joint in annular lig
what is the distal radioulnar joint articulation
- head of ulna
- TFCC
- ulnar notch radius
what is the radiocarpal/ulnocarpal joint articulation
- radius
- TFCC
- prox row carpals (not pisiform)
what is the midcarpal joint articulation
-prox and distal row
what is the TFCC
triangular fibrocartilage complex
what are the components of the TFCC
- biconcave fibrocartilage disc
- palmar ulnocarpal lig
- ulnar collateral lig
- dosral and volar radioulnar ligs sometimes
what is the function fo the TFCC
- major stabilizer DRUJ
- binds distal radius and ulna
- provides dual articular surface
- separates radioulnar from radiocarpal joint
- cushion- ulnar sided force transmission
how do TFCC injuries happen
variable
- FOOSH
- extension wtih ulnar compression
- forced radial or ulnar deviation
- strong distratcion force
what is the axis of rot for flex/ext
coronal axis between lunate and capitate
what is the axis of rot for rad/ulnar dev
sagittal between lunate and capitate
what is the axis fo rot for circumduction
polyaxial
in the midcarpal joint, what is the ulnar compartment
capitate and hamate
convex
in the midcarpal joint, what is the radial compartment
trapezium and trapezoid
- concave in dorsal/volar direction
- convex in radial/ulnar direction
which motion does the midcarpal joint prefer
extension
describe the ring system
- bones within each row tethered together by interosseuous ligs
- ring is only complete by addition of midcarpal ligs
- as long as ligaments in tact, carpal bones move together as a unit
describe the joint configuration at the radiocarpal/ulnocarpal joints
- flex/ext prox row rolls and glides opposite
- radial/ulnar dev prox row rolls and glides opposite
- RD: scaphoid/lunate flex (rocks)
- UD: prox row extend (twists)
-RD and UD limited in extremes of wrist flex and ext due to lig constraints
how many metacarpal bones
5
how many phalange bones
14
what kind of joint is the 1st carpometacarpal
sellar
describe the joint configuration of the distal surface of the trapezium
convex: radial/ulnar
concave: dosral/volar
describe the joint configuration of the prox surface of the 1st MC
concave: radial/ulnar for radial abd/adduction
concex: dorsal/volar for palmar abd/add
how many degrees of freedom in the thumb
3
talk about radial ab/ad in the thumb
MC rolls nad glides in SAME direction
talk about palmar ab/ad in the thumb
MC rolls and glides in OPP direction
what kind of joint is the thumb
condyloid
describe the joint configuration of carpometacarpal joint 2 and 3
difficulty to classify as interlocking articular surfaces prevent movement- stability
describe the joint configuration of carpometacarpal joint 4 and 5
- distal surface of hamate: slightly concave
- prox surface of 4 and 5 metacarpals: slightly convex
what do the degrees of freedom allow for
cupping of the hand by slight flexion and IR of metacarples
what is the function of the 2-5 fingers volar plates
ext: increases contact surface w MC head
flex: glides prox and prevents tendon pinching
talk about the joint configuration of metacarpophalangeal joints 2-5
ovoid
distal surface of metacarpals: biconvex
prox surface of phalanges: concave
describe flex/ext of phalanx
rolls and glides in SAME direction
describe ab/ad of phalanc
rolls nad glides in SAME direction
describe the joint configuation of interphalangeal joints 1-5 and thumb MP joint
true synovial hinge joints
- distal surface of prox phalanx: convex
- prox surface of distal phalanx: concave
