Shoulder muscles Flashcards
anterior muscles of shoulder
pec maj, subscap, coracobrachialis, and biceps brachi
posterior shoulder muscles
infraspinatus and teres minor
superior shoulder muscles
deltoid and supraspinatus
inf shoulder muscles
lats, teres major, and long head of triceps brachii
Pec major muscle action
prime mover of add, h add, and internal rot of humerus
shape of pec major
triangular
pec major origin
along medial clavicle and sternum
pec major insertion
intertubercular groove of humerus
pec maj clav portion muscles action
flex humerus
pec majr sternocostal portion extends
humerus from flexed position
coracobrachialis assist w/ what muscle actions
shoulder flexion and add
biceps brachii is what kind of jt and how many head muscle that crosses what?
The biceps is a 2-jt, 2 head muscle that corsses the shoulder and elbow
all 3 heads of deltoid insertions?
All heads insert @ deltoid tuberosity on lateral humerus
ant delt origin
anterolateral aspect of clavicle
ant delt is chiefly responsible for what muscle actions?
shoulder flexion, h add, and IR of GH jt
midd delt origin
lateral aspect of acromion
midd delt muscle action
abd of GH Jt
post delt origin
inferior aspect of scapular spine
post delt muscle action
GH ext, h abd, and ER, oppose ant delt
Which deltoid is usually more dvp’d ? Cuases what?
Ant more dvp’d than post delt causing imbalance.
Post under dvp than ant delt is imbalance that causes what?
postural abnormalities (shoulder fwd and IR) and may be related to shoulder problems such as shoulder impingement syndrome
What 4 muscles make up rotator cuff?
Subscap, Infraspinatus, Teres minor, and supraspinatus
rotator cuffs insertion
greater and lesser tubercles of humerus
rot cuffs origin
scapula
supraspinatus muscle action
iniates abd at GH Jt
infraspinatus and teres minor muscle action
externally rotates GH jt
subscap muscle action
IR GH jt
4 ways RC stabs shoulder?
passive muscle tension
contraction of muscles causng compression of articular surface
Jt motion that result in seconadry tightening of ligamentous restrainsts
barrier effect of contracted muscle
Lat dorsi origin
iliac crest and post sacrum via thoracolumbar fascia, lower 6 vertebrae, and lower 3 ribs
lats insertion
interubercular groove of humerus,
lats muscle action
strong extensor, IR, and add of GH jt
lats angle of pull when arm abd is
30-90
teres majr acts like
lats
pec minor origin
anterior aspects of 3rd - 5th ribs
pec minor insertion
coracoid process of scapula
When pec minor contracts, what muscle action occurs
protraction, downward rot, and depression of scapula
SA origin
several bands on upper 9 ribs laterally
SA insertion
ant aspect of medial border of scapula
SA muscle action
protracts scapula
SA is active in what motions
pushing and reaching
subclavius is a what and does what?
small muscle that protects and stabilizes SC jt
ant shoulder girdle muscles
pec minor, SA, and subcalvius
post shoulder girdle muscles
lev scap, Rh, traps
Lev scap origin
transverse processes of upper 4 cervical vertebrae, run obliquely
lev scap insertion
medial border superior to scapular spine
lev scap muscle action
elevation and downward rot of scapula, also act on neck
Rh origin
spinous processes of last cervical and upper 5 vertebrae
Rh insertion
medial border of scapula from spine to inf angle
traps origin
covers broad area from base of occipt to spinous process of 12th thoracic vertebra
traps insertion
lateral clavicle, medial border of acromion, and scapular spine
contraction of upper traps causes
scapular elevation
middle traps contraction cuases
scapular retraction
lower traps contraction
scapular depression
Together upper and lower traps cause
upward rot of scapula
