Anterior Shoulder - Axilla and Arm Muscles Flashcards
Pectoralis Major Clavicular Head Origin
anterior surface of medial half of clavicle
Pectoralis Major Insertion
Lateral lip of intertubercular sulcus of humerus
Pectoralis Major Action
Adducts and medially rotates the humerus; draws scapula anteriorly and inferiorly
Pectoralis Major Innervation
Lateral and medial pectoral nerves; clavicular head (C5,C6); sternocostal head (C7,C8,T1)
Pectoralis Minor Origin
3rd-5th ribs near their costal cartilages
Pectoralis Minor Insertion
Medial border and superior surface of coracoid process of scapula
Pectoralis Minor Action
Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
Pectoralis Minor Innervation
Medial Pectoral Nerve (C8,T1)
Serratus Anterior Origin
External surfaces of lateral parts of 1st-8th ribs
Serratus Anterior Insertion
Anterior surface of medial border of scapula
Serratus Anterior Action
Protracts the scapula and holds it against thoracic wall; rotates scapula
Serratus Anterior Innervation
Long thoracic nerve (C5,C6,C7)
Subclavius Origin
Junction of 1st rib and its costal cartilage
Subclavius Insertion
Inferior surface of middle third of clavicle
Subclavius Action
Anchors and depresses clavicle
Subclavius Innervation
Nerve to subclavius (C5,C6)
Corachobrachialis Origin
Tip of coracoid process of scapula
Corachobrachialis Insertion
Middle third of medial surface of humerus
Corachobrachialis Action
Helps flex and adduct arm; resists dislocation of shoulder
Corachobrachialis Innervation
Musculocutaneous nerve (C5,C6,C7)
Biceps Brachii Long head Origin
Supraglenoid tubercle of scapula
Biceps Brachii insertion
Tuberosity of radius and bicipital aponeurosis
Biceps Brachii action
Supinates forearm and flexes forearm when it is supinated; short head resists should dislocation
Biceps Brachii short head origin
tip of coracoid process of scapula
Biceps brachii innervation
Musculocutaneous nerve (C5,C6,C7)
Brachialis origin
Distal half of anterior surface of humerus
Brachialis insertion
Coronoid process and tuberosity of ulna
Brachialis Action
Flexes forearm in all positions
Brachialis Innervation
Musculocutaneous nerve (C5,C6) and radial nerve (C5,C7)
Triceps brachii medial head origin
Posterior surface of humerus, inferior to radial groove
triceps brachii lateral head origin
Posterior surface of humerus, superior to radial groove
triceps brachii long head origin
Infraglenoid tubercle of scapula
triceps brachii insertion
Proximal end of olecranon of ulna and fascia of forearm
triceps brachii action
Chief extensor of forearm; long head resists dislocation of the humerus; especially important during adduction
triceps brachii innervation
Radial nerve (C6,C7,C8)
Anconeus origin
Lateral epicondyle of humerus
Anconeus insertion
Lateral surface of olecranon and superior part of posterior surface of ulna
Anconeus Action
Assists triceps in extending forearm; stabilizes elbow joint; may abduct ulna during pronation
Anconeus Innervation
Radial nerve (C7,C8,T1)
Pectoralis Major Sternocostal Head Origin
anterior surface of sternum; superior six costal cartilages; aponeurosis of external oblique
Pectoralis Major Sternocostal head action
Extends the humerus from the flexed position
Pectoralis Major Clavicular Head action
Flexes humerus
