Shoulder arthrology - exam 3 Flashcards
describe sternoclavicular (SC) joint
clavicle on scapula
basilar joint of UE - links axial/appendicular skeleton
allows large ROM
irregular saddle shape
convex on concave
describe acromioclavicular (AC) joint
attaches scapula to clavicle
describe the scapulothoracic joint
not true joint
interface between bones
movements linked to movements at SC and AC
position of scapula provides base for GH joint
describe the glenohumeral (GH) joint
most distal and mobile portion of the whole complex
t/f
weakened, painful, or unstable link in the shoulder complex decreases the effectiveness of the entire UE
true
elevation of the shoulder has a (superior/inferior) slide
superior
depression of the shoulder has a (superior/inferior) slide
inferior
protraction of the shoulder results in what movement of the scapula in regards to medial border
medial border slides anterior/lateral
retraction of the shoulder results in what movement of the scapula in regards to medial border
medial border moves posterior/medial
upward rotation of shoulder results in what movement of the scapula in regards to inferior angle
inferior angle rotates
downward rotation of the shoulder results in what movement of the scapula in regards to the inferior angle
inferior angle moves in superior-lateral direction
downward rotation of the shoulder results in what movement of the glenoid fossa
glenoid fossa rotates inferior-medial direction
the longitudinal diameters of the sternoclavicular joint extend into what plane
frontal plane between superior/inferior points of articular surfaces
the transverse diameters of the sternoclavicular joint extends into what plane
horizontal plane between anterior/posterior points of articular surfaces
what are the periarticular tissues of the SC joint
anterior SC ligament
posterior SC ligament
interclavicle ligament
articular disc
SCM, sternothyroid, sternohyoid, subclavius muscles
how many degrees of freedom does the SC joint have
3 - sagittal, frontal, horizontal
what are the kinematic functions of the SC joint
elevates/depresses
protracts/retracts
rotates
what is the goal of the SC joint
place scapula in optimal position for head of humerus
clavicle rotates in all __ degrees of freedom with UE elevation
3
where is the axis of the SC joint
near anterior-posterior
how many degrees of elevation does the SC joint have
35-45
describe the arthrokinematics of clavicle elevation
convex surface rolls superiorly and slides inferiorly
what is the function of the CC ligament in the SC joint
stretches during clavicle elevation and limits motion
describe the arthrokinematics of clavicle depression
convex surface rolls inferiorly and slides superiorly
what is the function of the interclavicular ligament and superior portion of capsule
limits movement with clavicle depression
what plane does clavicular protraction/retraction occur
horizontal plane
where is the axis of motion for clavicular protraction/retraction
vertical
where does the arthrokinematics of scapular protraction/retraction occur
SC joint’s transverse diameter
describe the arthrokinematics of retraction at the SC joint
concave surface of clavicle rolls and slides posteriorly on convex surface of sternum
what is the function of the CC ligament and anterior capsule during clavicular retraction
stretches and resists excessive movement
describe the arthrokinematics of clavicular protraction
occurs in anterior direction
what is the function of CC ligament and posterior capsule during clavicular protraction
stretches to limit excessive movement
where is the axis during rotation of the clavicle
longitudinal
describe the arthrokinematics of rotation of the clavicle
spin of sternal end relative to lateral surface of the articular disc
t/f
axial rotation of the clavicle is linked with overall kinematics of flexion and abduction
true
where is the acromioclavicular joint located
lateral end of clavicle and acromion of scapula
what are the AC joint periarticular tissues
superior and inferior AC ligaments
coracoclavicular ligaments
trapezoid ligament and conoid ligament
describe the kinematics of the AC joint
motion between scapula and lateral clavicle
3 degrees of freedom
upward/downward rotation
describe upward rotation of scapula in regards to AC joint
swings upward and outward
up to 30 degrees
contributes significantly to scapulothroacic motion
describe downward rotation of scapular at the AC joint
return to anatomical position
frontal plane depicted
describe rotational adjustment motions at the AC joint
pivoting/twisting type motions of the scapula around lateral end of clavicle
aligns the scapula against the throax
describe rotational adjustment motions of the AC joint in the horizontal plane
vertical axis
medial border moves away
describe the rotational adjustment motions of the AC joint in the sagittal plane
medial-lateral axis
inferior angle pivots away or reverse (anterior or posterior tilting)
describe the motion of protraction at the AC joint
AC joint internally rotates in horizontal plane
helps align anterior surface of scapula with thorax curved surface
(anterior/posterior) tilting occurs with elevation
anterior tilting
describe the motion of scapular protraction/retraction of the scapula
summation of horizontal motions at SC and AC
protracting clavicle around SC joint, SC varies amount of internal rotation
scapulothoracic upward rotation is a summation of…
elevation at SC joint and upward rotation at AC joint
describe the glenohumeral joint general features
large convex head on shallow concavity
how is the humeral head positioned in the GH joint
medially, superiorly, posteriorly
describe the fibrous capsule of the GH joint
rim of glenoid fossa to anatomical neck
loose fitting
thin and expandable
allows mobility, reinforcement by external ligaments
in anatomical position, inferior portion of capsule is (slackened/taut) and is called ___
slackened
axillary pouch
what lines the inner wall of the GH joint
synovial membrane
the head of the humerus and glenoid fossa is lined with ___ cartilage
articular
potential volume of space in the GH joint is _x the size of humeral head
2
what is the primary stabilizers in the GH joint
passive tension with embedded ligaments
active forces produced by local muscles (rotator cuff)
LBB crosses superiorly overhead of humerus
superior GH capsular ligaments resist
external rotation, inferior and anterior translations
what is the function of the middle GH capsular ligaments
stabilizes most motions
main anterior restraint
slack in internal rotation
what is the function of inferior bands in GH capsule
3 portions
taut in 90 degree abductoin
supports and suspended humeral head
resists inferior and anterior post lateral translations
describe the coracohumeral ligament
attaches at coracoid process and greater tubercle
blends with superior capsule and supraspinatus tendon
taut in anatomical position
restraints inferior translation and external rotation of humeral head
location of the subscapularis muscle in regard to the capusle
anterior to capsule
supraspinatus, infraspinatus, teres minor location in regards to the capsule
superior and posterior
what is the rotator (cuff) interval
common site for dislocation
reinforced by LHB
coracohumeral ligament and superior/mid capsular ligs
where are the 2 regions of vulnerability in the rotator cuff
inferior and supraspinatus/subscapularis
where does the intrascapular tendon cross the humeral head
intertubercle groove on anterior humerus
what is the function of the long head of biceps tendon
restricts anterior translation of humeral head
force generated through tendon across dome of humeral head resists anterior translation
what are the tissues the reinforce/deepen GH joint
joint capsule/GH capsular ligs
coracohumeral ligament
rotator cuff muscles
LHB
glenoid labrum
describe the coracoacromial arch
formed by the coracoacromial ligament and acromion process
roof of GH joint
what does the coracoacromial arch contain
supraspinatus muscle and ligament
subacromial bursa
LHB
superior capsule
what is the subacromial bursa
direct extension of the synovial membrane of the GH joint
what is the purpose of bursa sacs
where can they be located
situated where significant frictional forces develop
between tendons, capsule, bone, muscle, ligament, 2 adjacent muscles
what are the bursa that are superior to the humeral head and what are their functions
subacromial bursa - protests SS from acromial bone
subdeltoid bursa - limits friction forces between deltoid and SS tendon/humeral head
what plane is humeral adduction/abduction motion
what is the axis
frontal
A-P axis
what is the slide/glide of humeral adduction/abduction
superior roll with inferior slide
describe adhesive capsulitis
excessive thickening or stiffness in ICL
limits inferior slide of humeral head
superior roll leads to jamming of humeral head against coracoacromial arch
only 22 degrees before this without any slide
describe impingement syndrome
unnatural and repeated compression/abrasion may damage SS tendon, subacromical bursa, LHB tendon, or superior parts of the capsule
over time repeated compression may lead to this syndrome
what plane is shoulder flexion
what is the axis
sagittal plane
ML
how many degrees is GH flexion
120
how many degrees of active and passive occurs in extension
65 degrees active, 80 degrees passive
describe scapular and capsule ligaments movements that occur during extension
slight anterior tilt of scapula
stretch capsular ligament
describe internal and external rotation of the shoulder
axial rotation of the humerus horizontal plane
longitudinal axis runs through the shaft
describe the arthrokinematics of external rotation
rolls posteriorly, slides anteriorly
describe the arthrokinematics of internal rotation
rolls anteriorly, slides posteriorly
what is the overall kinematics of shoulder abduction
motion not as specific joint but whole complex
ideal is optimal kinematic sequencing and/or coupling across joints
impairment in one part impacts the rest
what is the relationship of GH abduction and ST upward rotation
ratio of 2:1
every 3 degrees of abduction, 2 degrees at GH joint/1 at ST upward rotation
how many degrees does the SC elevate during the 180
30 degrees
the 60 degrees of scapula is a result of
simultaneous elevation of the clavicle at SC joint and upward rotation of the scapula at the AC joint
the clavicle retracts at the __ joint during full abduction
SC
Mhm
Mhm
the clavicle does more in what plane
frontal plan
how does the scapula tilt as full abduction occurs
scapula tilts posteriorly and slightly rotates outward
how is the scapula positioned at rest
anterior tilt 10 degrees
internally rotated 30-40 degrees
the posterior tiltand external rotation of the scapula during abduction helps by
keeps the scapula flush with throax
orients the fossa
moves the coracoacromial arch away from the advancing humeral head
how many degrees does the clavicle rotate during full abduction
20-35 degrees
what motion is the most predominant of the clavicle
abduction
those with subacrominal impingement showed reduced ___
rotation
what motion of the humerus naturally occurs during abduction
external rotation
what is the significance of natural external rotation with shoulder abduction
allows for the greater tubercle on the humerus to pass posterior to the acromion
