Shoulder - muscle and joint interaction - exam 3 Flashcards
what is the innervation of the SC joint
C3-C4 via cerviatl plexus
what is the innervation of the GH and AC joints
C5-6 via the suprascapular and axillary nerves
what nerves branch from the posterior cord of the brachial plexus
axillary
subscapular
throacodorsal
what nerves are considered the proximal segments of the bracial plexus
dorsal scapular
long thoracic
pectoral
suprascapular
what nerve supplies the deltoid and teres minor
axillary
what are the nerve roots of the axillary nerve
C5-6
what nerve supplies the latissimus dorsi
thoracodorsal
what are the nerve roots of the thoracodorsal nerve
C6-8
what nerve supplies the upper portion of the subscapularis
upper subscapular
what nerve supplies the lower subscapularis and the teres major
lower subscapular nerve
what are the nerve roots of the subscapular nerve
C5-6
what nerve supplies the pectoralis major
lateral pectoral
what nerve supplies the pectoralis major and pectoralis minor
medial pectoral
what are the nerve roots for the pectoral nerve
C5-T1
what nerve supplies the supraspinatous and infraspinatus
suprascapular
what are the nerve roots for the suprascapular nerve
C5-6
what nerve supplies the subclavius
subclavian
what nerve supplies the rhomboids and levator scapula
dorsal scapular
what are the nerve roots of the dorsal scapular nerve
C5
what nerve supplies the serratus anterior
long throacic
what are the nerve roots of the long thoracic nerve
C5-7
describe proximal stabilizers
originate on spine/ribs/cranium
insert on scapula or clavicle
describe distal mobilizers
originate on scapula/clavicle
insert on humerus/forearm
what muscles are elevators at the ST joint
upper trap
levator scapulae
rhomboids
what muscles are depressors at the ST joint
lower trap
latissimus dorsi
pec minor
subclacius
what muscles are protractors at the ST joint
serratus anterior
what muscles are retractors at the ST joint
middle trap
rhomboids
lower trap
what muscles are upward rotators at the ST joint
serratus anterior
upper/lower trap
what muscles are downward rotators at the ST joint
rhomboids
pec minor
if the upper trap, levator scapulae, and rhomboid lost their endurance/strength, what would happen to the scapula?
scapula depressed, protracted, and excessively downwardly rotated scapula
t/f
depression can raise the thorax if the arm is physically blocked or if the scapula is stabilized/fixed
true
motions at the ST joint occur because of motions at…
SC and AC joints
the clavicle elevates or rolls and slides opposite at what joint
SC
what are the muscles that elevate the humerus at the GH joint
anterior/middle deltoid
supraspinatus
coracobrachialis
biceps bracii
if the deltoid is paralysed, can the supraspinatus still abduct the arm?
yes
slide 20 lecture 10
at 90 degrees abduction, humeral head stretches ____ ligament which acts like a hammock supporting the head of the humerus
ICL/axillary pouch
active contraction pulls the capsule (tight/loose) to prevent it from being pinched between humeral head/acromion
tight
upward rotators of the ST joint is essential for what motion of the UE
elevation
what muscles are responsible for the upward drive and rotational adjustments of the scapula when elevating the UE
Serratus anterior
upper and lower trap
what muscle has the best leverage for UE upward rotation of the UE
Serratus anterior
what muscles posteriorly tilt the scapula relative to the axis of rotation at the AC joint
serratus anterior and lower trap
what muscles work to externally rotate the scapula relative to the axis of motion at he AC joint
serratus anterior and middle trap
what are signs/symptoms that indicate weak traps
with full abd, t spine extends 10-15 degrees
elevation can happen with difficulty getting high
excessive protraction
an injury of the long thoracic nerve can result in..
paralysis fo the right serratus anterior
what signs/symptoms indicate weakness of the serratus anterior
downwardly rotated position
scapula is anteriorly tilted and internally rotated
describe scapular dyskinesis
any abnormal position/movement of the scapula
what signs indicate scapular dyskinesis
reduced upward rotation
excessive downward rotation, internal rotation, anterior tilt/elevation
what are the 3 categories of scapular dyskinesis
type 1 - inferomedial border
type 2 - entire medial border
type 3 - superomedial border
what are the 3 categories of scapular dyskinesis
type 1 - inferomedial border
type 2 - entire medial border
type 3 - superomedial border
what are the 3 categories of scapular dyskinesis
type 1 - inferomedial border
type 2 - entire medial border
type 3 - superomedial border
what is the purpose of the rotator cuff muscles
control dynamic stability and arthrokinematics of the GH joint
what is the function of the supraspinatus during GH abduction
rolls the humeral head superiorly and toward abduction and compresses joint
what muscles translate the humeral head downward to counteract superior translation
subscapularis
infraspinatus
teres minor
during abduction of the GH joint, the internal moment arm is used by what 2 muscles
deltoid and supraspinatus
what 2 muscles externally rotate humerus to increase clearance of greater tubercle and acromion
infraspinatus and teres minor
how does the supraspinatus control the arthrokinematics of the GH joint during abduction
drives superior roll of humeral head
compresses humeral head against glenoid fossa
creates spacer above humeral head to restrict superior translation of humerus
how does the infraspinatus/teres minor/subscapularis control the arthrokinematics of the GH joint during abduction
exert a depression force on humeral head
teres minor and infraspinatus externally rotate humerus
what muscles adduct and extend shoulder
posterior deltoid
latissimus dorsi
teres major
long head of triceps brachii
pec major
infraspinatus
teres minor
what muscles stabilize the scapula during shoulder adduction and extension
rhomboids
what muscles internally rotate the shoulder
subscapularis
pec major
latissimus dorsi
teres major
anterior delt
what muscles externally rotate the shoulder
infraspinatus
teres minor
posterior delt
t/f
external rotation requires the scapula to be stable
true
