Muscles Of The Shoulder (2) Flashcards
What’s the origin of the deltoid?
Lateral 1/3 of clavicle
Acromion
Spine of scapula
What’s the attachment of the deltoid?
Deltoid tuberosity
What is the function of the anterior part of the deltoid?
Flexes and medially rotates arm
What is the function of the middle part of the deltoid?
Abducts arm
What is the function of the posterior part of the deltoid?
Extends and laterally rotates arm
What is the origin of the teres major?
Inferior angle of scapula
What is the attachment of the teres major?
Medial lip of intertubercular sulcus
What is the function of the teres major?
Adducts and medially rotates arm
What is the origin of the supraspinatus?
Supraspinatus fossa
What is the attachment of the supraspinatus?
Superior facet of greater tubercle of humerus
What is the function of the supraspinatus?
Initiates and assists deltoid in abduction of arm
Acts with other rotator cuff muscles
What is the origin of the infraspinatus?
Infraspinatus fossa
What is the attachment of the Infraspinatus?
Middle facet of greater tubercle of humerus
What is the function of the Infraspinatus?
Laterally rotates arms
Acts with other rotator cuff muscles
What is the origin of the teres minor?
Middle part of lateral border of scapula
What is the attachment of the teres minor?
Inferior facet of greater tubercle of humerus
What is the function of the teres minor?
Laterally rotates arm
Acts with other rotator cuff muscles
What is the origin of the subscapularis?
Subscapular fossa
What is the attachment of the subscapularis?
Lesser tubercle of the humerus
What is the function of the subscapularis?
Medially rotates arm
Helps hold humerus in glenoid cavity with rotator cuff muscles
What muscles aid in elevation of scapula?
Trapezius (descending part)
Levator scapulae
Rhomboids
What muscles aid in depression of scapula?
Pec major (inferior sternocostal head)
Latissimus Dorsi
Trapezius (ascending part)
Serratus anterior (inferior part)
Pec minor
What muscles aid in protraction of scapula?
Serratus anterior
Pec major
Pec minor
What muscles aid in retraction of scapula?
Trapezius (middle part)
Rhomboids
Latissimus dorsi
What muscles aid in upward rotation of scapula?
Trapezius (descending part)
Trapezius (ascending part)
Serratus anterior (inferior part)
What muscles aid in downward rotation of scapula?
Levator scapulae
Rhomboids
Lattisimus dorsi
Pec minor
Pec major (inferior sternocostal head)
What two muscles of mastication work together?
Masseter and medial pterygoid
What are the advantages of the rotator cuff?
Compresses humerus into glenoid fossa
Limits superior translation
Axis rotation
What may damage the axillary nerve?
Fracture of surgical neck
What is an important site for axillary nerve issues?
Quad (teres minor, teres major, humerus, long head of triceps)
