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
Origin of Rhomboids Major
SP’s of T2-5
Origin of Rhomboids Minor
SP’s of C7-T1
Inferior end of nuchal ligament
Insertion of Rhomboids Major
Medial border of scapula inferior to scapular spine
Insertion of Rhomboids Minor
Medial border of scapula at the root of scapular spine
Action of Rhomboids Major
Retracts, elevates and rotates scapula inferiorly
Actions of Rhomboids minor
Retracts, elevates and rotates scapula inferiorly
Origin of Serratus Anterior
Ribs 1-8/9
Insertion of Serratus Anterior
Medial border of scapula on its costal surface
Action of Serratus Anterior
Draws scapula forward, inferior fibers rotate scapula superiorly
Insertion of Subclavius
Inferior surface of clavicle
Origin of Subclavius
1st rib and its cartilage
Action of Subclavius
Draws clavicle (hence shoulder) down and forward
Origin of subscapularis
Subscapular fossa
Insertion of subscapularis
Lesser Tubercle of humerus
Action of Subscapularis
Medially rotates arm ; assists extension of arm
Origin of Supraspinatus
Supraspinatus fossa
Insertion of Supraspinatus
Greater tubercle of humerus (highest facet)
Action of Supraspinatus
Abducts the arm (initiates abduction)
Origin of Teres Major
Dorsal surface of the inferior angle of the scapula
Insertion of Teres Major
Crest of the lesser tubercle of humerus
Action of Teres Major
Adducts and medially rotates arm ; assists in extension (lats little help)
Origin of Teres Minor
Upper 2/3 of lateral border of scapula
Insertion of Teres Minor
Greater tubercle of humerus (lower facet)
Action of Teres Minor
Laterally rotates arm
Origin of Trapezius
Medial 1/3 of superior nuchal line
External occipital protuberance
Nuchal ligament
SP’s C7-T12
Insertion of Trapezius
Lateral 1/3 of clavicle
Medial side of acromion
Upper crest of scapular spine
Tubercle of scapular spine
Action of Trapezius
Elevates and depresses scapula (depending on what part of muscle is contracting)
Rotates scapula superiorly
Retracts scapula
