Shoulder Muscles Flashcards
Origin of the Deltoid
Lateral 1/3 of clavicle
Acromion
Lower lip of the crest of the scapular spine
Insertion of Deltoid
Deltoid tuberosity of humerus
Action of Deltoid
Abducts arm
Anterior fibers: Flex & medially rotate arm
Posterior fibers: Extend and laterally rotate arm
Origin of Infraspinatus
Infraspinatus fossa
Insertion of Infraspinatus
Greater tubercle of humerus (middle facet)
Action of Infraspinatus
Laterally rotates arm
Origin of Latissimus Dorsi
SP’s T7-L5
Posterior 1/3 of iliac crest
Lower 3-4 ribs
(sometimes from inferior angle of scap)
Insertion of Latissimus Dorsi
Floor of Intertubercular Groove
Action of Latissimus Dorsi
Extends and rotates arm medially
Origin of Levator Scapulae
TVP’s C1-4
Insertion of Levator Scapulae
Medial border of scapula from the superior angle of the spine
Action of Levator Scapulae
Elevates Scapula
Origin of Pectoralis Major
Medial 1/2 of the clavicle
Manubrium & body of sternum
Costal cartilage of ribs 2-6
(Sometimes from the rectus sheath of the upper abdominal wall
Insertion of Pectoralis Major
Crest of greater tubercle of humerus
Action of Pectoralis Major
Flexes, medially rotates and adducts the arm
Origin of Pectoralis Minor
Ribs 3-5
Insertion of Pectoralis Minor
Coracoid process of scapula
Action of Pectoralis Minor
Draws the scapula forward, medial and downward