Back/Pectoral Region/Rotator Cuffs Flashcards
name the superficial back muscles
trapezius, lattissimus dorsi, levator scapulae + rhomboids (major and minor)
which muscles are involved in arm abduction?
supraspinatus (5-15 degrees), deltoid (up to 90), trapezius
what is the action and innervation of the trapezius?
accessory nerve.
upper fibres = abduction of arm
middle fibres = retract scapula
lower fibres = pull scapula inferiorly
what is the action and innervation of the lattissimus dorsi?
thoracodorsal nerve.
extends, adducts + medially rotates upper limb
what is the action and innervation of levator scapulae?
dorsal scapular nerve
elevates scapula
what muscle does the thoracodorsal nerve innervate?
lattissimus dorsi
what does the dorsal scapular nerve innervate?
levator scapulae and both rhomboids
which is superior, rhomboid major or minor?
minor
what is the action and innervation of rhomboid major/minor?
dorsal scapular nerve
retracts + rotates scapula
which wall of the axilla do the pec major/minor muscles contribute to?
anterior
what are the two heads of pectoralis major, and where do they insert to?
clavicular and sternocostal
both insert together in the bicipital groove
what is the action and innervation of pectoralis major?
adduct and medially rotate arm (clavicular head also flexes)
medial + lateral pectoral nerves
what is the action and innervation of pectoralis minor?
medial pectoral nerve
depresses shoulder
to which wall of the axilla does the serratus anterior contribute?
medial
what is the action and innervation of serratus anterior?
long thoracic nerve
rotates scapula, allowing arm to be raised over 90 degrees
what does the long thoracic nerve supply?
serratus anterior
name the 6 intrinsic shoulder muscles?
deltoid + teres major, plus the 4 rotator cuff muscles:
supraspinatus, infraspinatus, subscapularis + teres major
what is the action and innervation of the deltoids?
axillary nerve
anterior fibres flex arm @ shoulder
middle fibres - major arm abductor (5-90 degrees)
posterior fibres - extend arm @ shoulder
what is the action and innervation of teres major?
lower subscapular nerve
adducts @ shoulder + medially rotates the arm
which of teres major/minor is a rotator cuff muscle?
minor
what are the 4 rotator cuff muscles?
supraspinatus, infraspinatus, subscapularis + teres minor
what is the main action of the rotator cuff muscles?
hold humeral head in the glenoid fossa, stabilising the joint
what is the action and innervation of supraspinatus?
suprascapular nerve
abduction 0-5 degrees, and assists deltoids for 5-90 degrees
what is the action and innervation of infraspinatus?
suprascapular nerve
lateral rotation of arm
which two muscles does the suprascapular nerve innervate?
supraspinatus and infraspinatus
what is the action and innervation of subscapularis?
upper and lower subscapular nerve
medially rotates arm
what is the action and innervation of teres minor?
axillary nerve
laterally rotates arm
