Scapular Muscles Flashcards
Identify proximal and distal attachment sites, actions, and nerve innervation
Deltoid
Proximal attachment: Clavicle, acromion, and spine of the scapula
Distal attachment: Deltoid tuberosity of the humerus
Action: Humeral flexion & medial rotation (anterior), abduction (middle), extension & lateral rotation (posterior)
Innervation: Axillary nerve
Common Spinal Segments: C5-C6
Supraspinatus
Rotator cuff muscle
Proximal attachment: Medial 2/3 of supraspinous fossa
Distal attachment: Superior facet of the greater tubercle of the humerus and shoulder joint capsule
Action: Initiates humeral abduction & laterally rotates humerus, also stabilizes glenohumeral joint in the superior aspect of the joint
Innervation: Suprascapular nerve
Common Spinal Segments: C4-C6
Infraspinatus
Rotator cuff muscle
Proximal attachment: Medial 2/3 of infraspinous fossa
Distal attachment: Middle facet of the greater tubercle and shoulder joint capsule
Action: Humeral lateral rotation, stabilizes glenohumeral joint
Innervation: Suprascapular nerve
Common Spinal Segments: C5-C6
Subscapularis
Rotator cuff muscle
Proximal attachment: Subscapular fossa
Distal attachment: Lesser tubercle of the humerus
Action: Humeral medial rotation, stabilizes glenohumeral joint
Innervation: Upper & lower subscapular nerves
Common Spinal Segments: C5-C6
Teres major
Proximal attachment: Dorsal surface of the inferior angle of the scapula & lower 1/3 of the lateral border of the scapula
Distal attachment: medial lip of the intertubercular sulcus of the humerus
Action: Humeral adduction, medial rotation, & extension
Innervation: Lower subscapular nerve
Common Spinal Segments: C5-C6
Teres minor
Rotator Cuff Muscle
Proximal attachment: Upper 2/3 of the dorsal surface of the lateral border of the scapula
Distal attachment: Inferior facet of the greater tubercle of the humerus & shoulder joint capsule
Action: Humeral lateral rotation, stabilizes glenohumeral joint
Innervation: Axillary nerve
Common Spinal Segments: C5-C6
