Muscle Origin
What is the origin of the subscapularis muscle?
-medial 2/3 of the subscapular fossa and the adjoining fascia
What are the musclese of the rotator cuff?
-teres minor
-infraspinatus
-supraspinatus
-subscapularis
What is the blood supply of the supraspinatus musle?
What is the blood supply of the infraspinatus muscle?
Supraspinatus: suprascapular and dorsal scapular arteries
Infraspinatus: suprascapular, dorsal scapular, and scapular circumflex arteries
What are the actions of the teres major?
-extension, medial rotation of humerus, and adduction
What is the insertion of the deltoid?
-deltoid tuberosity on lateral mid-shaft of the humerus
What is he origin of the teres minor?
-along lateral 2/3 border of the scapula and posterior surface of adjoining fascia
What is the innervation of the teres minor and deltoid muscles?
-axillary n. (C5,6)
What is the blood supply of the teres major?
-thoracodorsal artery
What are the actions of the teres minor AND infraspinatus muscles?
-external rotation of the humerus and stabilization of GH joint
What is the insertion of the teres major?
-medial border of the intertubercular groove of the humerus
What is the origin of the teres major?
-along the inferior 1/3 of the lateral and posterior borders of the scapula and adjoining fascia
What is the innervation of the supraspinatus and infraspinatus muscels?
-Supraspinatus: suprascapular n. (C4,5,6)
-infraspinatus: suprascapular n. (C5,6)
What is the blood supply of the teres minor?
-suprascapular and scapular circumflex arteries
What are the actions of the supraspinatus muscle?
-abduction to 15 degrees, stabilize GH joint, prevent downward translation
What is the insertion of the supraspinatus?
What is the insertion of the infraspinatus?
Supraspinatus: superior facet of the greater tubercle of humerus and blends with GH capsule
Infraspinstus: middle facet of the greater tubercle of humerus and blends with GH capsule
What is the origin of the infraspinatus?
What is the origin of the supraspinatus?
-medial 2/3 of the infraspinatus fossa and fascia
-medial 2/3 of the suprspinatus fossa and fascia
What is the innervation of the teres major?
-lower subscpaular n. (C5,6,7)
What is the blood supply of the subscapularis?
-subscapular artery
What are the actions of the subscapularis muscle?
-internal rotation of the humerus and stabilization of the GH joint
What is the insertion of the teres minor?
-inferior facet of the greater tubercle of humerus and blends with GH capsule
What is the origin of the deltoid?
Anterior: laterla 1/3 of the clavicle along the anterior and superior surface
Middle: superlateral surface of acromion
posterior: inferior lip of spine of the scapula
What is the innervation of the subscapularis muscle?
-lower and upper subscapular n. (C5,6)
What is the blood supply for the deltoid?
-thoracoacromial trunk (deltoid/acromial arteries)
-anterior/posterior humeral circumflex arteries
What are the actions of the deltoids?
Anterior: flex and medially rotate the humerus
Middle: abduct the arm
Posterior: extend and laterally rotate the humerus
What is the insertion of the subscapularis muscle?
-lesser tubercle of humerus and blends with GH capsule