Quiz 2- Rotator Cuff

Question 1

Deltoid

Answer 1

Origin: Lateral third of clavicle, acromion, and spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Anterior part: flexes and medially rotates arm; Middle part: abducts arm; Posterior part: extends and laterally rotates arm
Innervation: Axillary nerve (C5 and C6)
Arterial Supply: Deltoid branch of thoracoacromial artery

Question 2

Supraspinatus

Answer 2

Origin: Supraspinous fossa of scapula
Insertion: Superior facet on greater tuberosity of humerus
Action: Initiates and assists deltoid in abduction of arm and acts with other rotator cuff muscles
Innervation: Suprascapular nerve (C4, C5 and C6)
Arterial Supply: Suprascapular artery

Question 3

Infraspinatus

Answer 3

Origin: Infraspinous fossa of scapula
Insertion: Middle facet on greater tuberosity of humerus
Action: Laterally rotate arm; helps to hold humeral head in glenoid cavity of scapula
Innervation: Suprascapular nerve (C5 and C6)
Arterial Supply: Suprascapular and circumflex scapular arteries

Question 4

Teres Minor

Answer 4

Origin: Superior part of lateral border of scapula
Insertion: Inferior facet on greater tuberosity of humerus
Action: Laterally rotate arm; helps to hold humeral head in glenoid cavity of scapula
Innervation: Axillary nerve (C5 and C6)
Arterial Supply: Subscapular and circumflex scapular arteries

Question 5

Subscapularis

Answer 5

Origin: Subscapular fossa of scapula
Insertion: Lesser tuberosity of humerus
Action: Medially rotates arm and adducts it; helps to hold humeral head in glenoid cavity of scapula
Innervation: Upper and lower subscapular nerves (C5, C6 and C7)
Arterial Supply: Subscapular artery

Question 6

Pectoralis Major

Answer 6

Origin: Clavicular head: anterior surface of medial half of clavicle; Sternocostal head: anterior surface of sternum, superior six costal cartilages, and aponeurosis of external oblique muscle
Insertion: Lateral lip of intertubercular groove of humerus
Action: Adducts and medially rotates humerus; draws scapula anteriorly and inferiorly; Acting alone: clavicular head flexes humerus and sternocostal head extends it
Innervation: Lateral and medial pectoral nerves; clavicular head (C5 and C6, sternocostal head (C7, C8, and T1)
Arterial Supply: pectoral branch of the thoracoacromial trunk

Question 7

Pectoralis Minor

Answer 7

Origin: 3rd to 5th ribs near their costal cartilages
Insertion: Medial border and superior surface of coracoid process of scapula
Action: Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall
Innervation: Medial pectoral nerves; clavicular head (C8 and T1)
Arterial Supply: Pectoral branch of the thoracoacromial trunk