Exam 2 Flashcards
what joints make up the shoulder complex?
- sternoclavicular
- acromioclavicular
- glenohumeral
- scapulothoracic
what type of joint is the sternoclavicular
saddle joint
what does the sternoclavicular joint look like at rest?
joint space is wedge shaped and open superiorly
what does the sternoclavicular disc do?
- creates two joint spaces
- increases joint congruency
- absorbs forces
- helps limit medial movement of clavicle
osteokinematics of sternoclavicular joint
- elevation/depression
- protraction/retraction
- anterior/posterior rotation
in elevation/depression the SC joint moves….
convex on concave
elevation of SC joint is
superior roll, inferior glide
depression of SC joint is
inferior roll, superior glide
in protraction/retraction the SC joint moves….
concave on convex
protraction of SC joint is..
anterior roll and glide
retraction of SC joint is
posterior roll and glide
arthrokinematics of posterior rotation of SC joint
the inferior surface turns anteriorly
- also called backward rotation
arthrokinematics of anterior rotation of SC joint
inferior surface returns to inferior position
closed pack position of SC joint
full posterior rotation
what type of joint is the acromioclavicular joint
plane synovial
what is the primary function of the AC joint
to allow the scapula to rotate during arm movement
what are the osteokinematics of the AC joint
- internal/external rotation
- anterior/posteror tilting (tipping)
- upward/downward rotation
what is the plane of the scapula
35 degrees off of the frontal
what does internal/external rotation of the AC joint help with?
helps to maintain contact of scapula on curved thorax during protraction and retraction of clavicle
what does anterior/posterior tilting of the AC joint help with?
helps to maintain contact of scapula on curved thorax during elevation and depression of clavicle
upward rotation of AC joint is associated with..
scapula swings upwardly and outwardly
- component of abduction and flexion
what is the closed pack position of the AC joint
full upward rotation (in flexion or abduction)
what are the primary movements of the scapulothoracic joint
- elevation/depression
- protraction/retraction
- upward/downward rotation
what are the secondary movements of the scapulothoracic joint
- anterior/posterior tilting
2. internal/external rotation
what is the combined motion of elevation of the scapulothoracic joint?
combined motion of SC joint elevation and AC joint downward rotation
- shoulder shrug
what is protraction of the scapulothoracic joint
combination of SC joint protraction and slight AC joint IR
what is upward rotation of the scapulothoracic joint
summation of SC joint elevation and AC joint upward rotation
- observed during flexion/abduction
what is the GH angle of inclination
130-150 degrees in frontal plane
what is angle of torsion for GH joint
30 degrees posterior in transverse plane
retroversion of GH
- same as angle of torsion
- posterior orientation of humeral head with regards to condyles
increased humeral retroversion is associated with…
increased ER ROM and reduced IR ROM
glenoid labrum
enhances concavity and increases articular surface
- attachment for GH ligaments and tendon of biceps long head
GH joint capsule
- inf portion is slack in adducted position creating an axillary pouch
tightness in posterior shoulder capsule would result in…
increased anterior humeral head translation which will decrease the subacromial space
what are the ligaments of the GH joint
- superior
- middle
- inferior GH lig
- coracohumeral lig
what does the superior GH ligament do
limits ER and anterior and inferior translation at 0 degrees of abduction
- slackens when abducted beyond 35-45 degrees
what does the middle GH ligament do
limits anterior translation from 45-90 degree abduction and extremes of external rotation
what does the inferior GH ligament do
primary stabilizer beyond 45 degrees of abduction or with combined abduction and rotation
what are the components of the inferior GH ligament
- anterior band
- posterior band
- axilarry pouch
what does the coracohumeral ligament do
limits inferior translation and ER of humeral head with the arm in dependent position
what 2 areas foes the rotator cuff not reinforce
- inferiorly
2. region between subs cap and supraspinatus
arthrokinematics of GH flexion
superior roll, inferior glide
arthrokinematics of GH extension
inferior roll, superior glide
arthrokinematics of GH adduction
inferior roll, superior glide
arthrokinematics of GH abduction
superior roll, inferior glide
arthrokinematics of GH ER
posterior roll, anterior glide
arthrokinematics of GH IR
anterior roll, posterior glide
closed pack position of GH
90 degrees abducted and full ER or full abduction and ER
capsular pattern of GH
external rotation > abduction > IR
what is scapulohumeral rhythm
ratio of 2 degrees of GH to 1 degree of scapular motion
when the rhomboids and lower trap act together…
results in pure retraction
what is the force couple for upward rotation?
serrates anterior
upper trap
lower trap
what are the aspects of the joint capsule of the elbow complex
- weak anteriorly and posteriorly
- fat pads are located between the capsule
what is the carrying angle
medial portion of the trochlea projects more distally than the lateral portion
- combo of shoulder ER, elbow extension and forearm supination
- angle varies from 8-15 degrees
what does the lateral collateral ligament do
stabilizes agents varus torque and combined varus and supination torques
arthrokinematics of elbow flexion
roll anterior, slide anterior
arthrokinematics of elbow extension
roll posterior, slide posterior
closed pack humeroulnar
full extension and supination
closed pack humeroradial
90 degrees elbow flexion and 5 degree supination
open pack humeroulnar
flexed 70, supinated 10
open pack humeroradial
full extension and supination
elbow capsular pattern
flexion > extension
in a closed pack position moving into pronation requires what..`
requires ER of the humerus and ulna
what is the closed pack position of the proximal radioulnar joint
5 deg of supination
what is the open pack position of the proximal radioulnar joint
70 deg of flexion, 35 deg of supination
capsular pattern of proximal radioulnar joint
supination = pronation
closed pack position of distal radioulnar joint
5 deg of supination
open pack position of distal radioulnar joint
10 deg of supination
capsular pattern of distal radioulnar joint
supination = pronation
what is the law of parsimony
nervous system tends to activate the fewest muscles or muscle fibers possible for the control of a given joint action
what is the goal of the law of parsimony?
energy efficiency
what joints make up the wrist/hand
- distal radioulnar
- radiocarplal, midcarpal
- carpometacarpal
- metacarpal
- interphalangeal
what is the wrist joint
condyloid
how many tendons go through the carpal tunnel
9
arthrokinematics of wrist flexion
anterior roll, posterior glide
arthrokinematics of wrist extension
posterior roll, anterior glide
arthrokinematics of wrist radial deviation
lateral roll, medial glide
arthrokinematics of ulnar deviation
medial roll, lateral glide
closed pack position of the wrist
full extension w radial deviation
open pack position of the wrist
neutral flexion/extension with slight ulnar deviation
capsular pattern
flexion = extension, slight radial and ulnar deviation
at what position is max grip?
30 degrees of extension
which wrist flexor is the strongest?
flexor carpi ulnaris
where is peak wrist flexion torque
40 degrees of wrist flexion
what is active wrist extension typically coupled with?
active radial deviation
what do the ulnar and radial collateral ligaments do?
stabilize the thumb
what are the arthrokinematics of thumb abduction
anterior roll, posterior glide
what are the arthrokinematics of thumb adduction
posterior roll, anterior glide
what is moving on what in thumb abduction/adduction
convex articular surface of thumb metacarpal moving on concave trapezium
what is moving on what in thumb flexion/extension
concave surface of metacarpal moving on convex diameter of trapezium
what is moving on what in thumb flexion
medial roll and glide
what is moving on what in thumb extension
lateral roll and glide
what makes up thumb opposition
abduction, flexion, IR
what is moving on what in thumb reposition
adduction, extension, ER
what is the closed pack position of the 1st CMC joint
full opposition
what is the open pack position of the 1st CMC joint
mid flexion/extension and mid abduction/adduction
what is the closed pack position of the 2nd-5th CMC joint
full flexion
what is the open pack position of the 2nd - 5th CMC joints
mid flexion/extension
what is the capsular pattern of 1st CMC joint
abduction
what type of joint are the metacarpophalangeal joints
condyloid
what are the arthrokinematics of MCP flexion
anterior roll and glide
what are the arthrokinematics of MCP extension
posterior roll and glide
what are the arthrokinematics of MCP abduction
roll and glide away from 3rd digit
what are the arthrokinematics of MCP adduction
roll and glide toward 3rd digit
what is the closed pack position of the MCP
full flexion
what is the open pack position of the MCP
slight flexion