Muscles Acting on Scapula and humerus Flashcards
Pectoralis major
O- sternal end of clavicle, sternum, cartilage of ribs 1-6; I- tendon which attaches fibers to intertubercular sulcus & greater tubercle of humerus
(superficial)
Action- adducts & medially rotates arm
Pectoralis minor
O- anterior surfaces of ribs 3-5; I- coracoid process of scapula
(deep)
Action- draws scapula forward and downward
Serratus Anterior
O- ribs 1-8/9; I- anterior, medial border of scapula
Action- protracts scapula, helps pushing/punching
Levator scapulae
O- transverse processes of C1-4; I- medial border of scapulae (it’s posterior neck)
(deep)
Action- elevates scapula
Rhomboid Major
O- spinous process of T2-T5; I- medial border of scapula
(deep)
Action- retracts scapula
Rhomboid Minor
O- spinous process of C7 & T1; I- medial border of scapula
(deep)
Action- retracts scapula
Trapezius
O- occipital bone, nuchal ligament, & spinous processes of T1-12; I- clavicle, acromion, & spine of scapula
(superficial)
Action- elevates, retracts, and rotates scapula
Supraspinatus
O- supraspinous fossa of scapula; I- greater tubercle of humerus
Action- abducts arm
Infraspinatus
O- infraspinous fossa of scapula; I- greater tubercle of humerus
Action- laterally rotates arm
Teres minor
O- lateral border of scapula; I- greater tubercle of humerus
Action- laterally rotates arm
Subscapularis
O- subscapular fossa of scapula; I- lesser tubercle of humerus
Action- medially rotates arm
Muscles of rotator cuff (SITS)
supraspinatus, infraspinatus, teres minor, subscapularis
Deltoid
O- clavicle, acromion process, & spine of scapula; I- deltoid tuberosity
Action- prime mover of abduction of arm
Coracobrachialis
O- coracoid process of scapula; I- medial side of diaphysis of humerus
Action- adduct (move it back after abduction) and flex arm (lifting straight up anteriorly)
Latissiumus dorsi
O- spinous processes of T6-L5, iliac crest, and ribs 9-11/12; I- floor of intertubercular sulcus
Action- prime mover of arm extension (moving it posteriorly), also arm adduction
