Upper Limb

Question 1

What is the origin of the pectoralis major

Answer 1

Distal attachment of both heads is into the intertubercular sulcus of the humerus

Question 2

What is the insertion of the pectoralis major

Answer 2

Proximal attachment of the clavicular head= anterior surface of the medial half of the clavicle. The sternocostal head= proximally to the anterior surface of the sternum

Question 3

What is the innervation of the pectoralis major

Answer 3

Lateral and medial pectoral nerve. Clavicular head= C5-C6. Sternocostal head= C7-T1

Question 4

What is the action of the pectoralis major

Answer 4

Adducts and medially rotated the humerus, draws the scapular anteroinferiorly, on its own the clavicular head flexes the humerus and the sternocostal head extends it

Question 5

What are the rotator cuff muscles

Answer 5

Supraspinatous, infraspinatous, teres minor, subscapularis

Question 6

What is the origin of the supraspinatous

Answer 6

Supraspinous fossa of the scapula

Question 7

What is the insertion of the supraspinatous

Answer 7

Greater tubercle of the humerus

Question 8

What is the innervation of the supraspinatous

Answer 8

Suprascapular nerve

Question 9

What is the action of the supraspinatous

Answer 9

Abducts the arm for the first 15 degrees then assists the deltoid for 15-90 degrees

Question 10

What is the origin of the infraspinatous

Answer 10

Infraspinous fossa of the scapula

Question 11

What is the insertion of the infraspinatous

Answer 11

Greater tubercle of the humerus

Question 12

What is the innervation of the infraspinatous

Answer 12

Suprascapular nerve

Question 13

What is the action of the infraspinatous

Answer 13

Laterally rotates the arm

Question 14

What is the origin of the teres minor

Answer 14

Posterior surface of the scapula, adjacent to its lateral border

Question 15

What is the insertion of the teres minor

Answer 15

Greater tubercle of the humerus

Question 16

What is the innervation of the teres minor

Answer 16

Axillary nerve

Question 17

What is the action of the teres minor

Answer 17

Laterally rotates the arm

Question 18

What is the origin of the subscapularis

Answer 18

Subscapular fossa on the costal surface of the scapula

Question 19

What is the insertion of the subscapularis

Answer 19

Lesser tubercle of the humerus

Question 20

What is the action of the subscapularis

Answer 20

Medially rotates the arm

Question 21

What is the origin of the deltoid

Answer 21

Scapula and clavicle

Question 22

What is the insertion of the deltoid

Answer 22

Deltoid tuberosity on the lateral surface of the humerus

Question 23

What is the innervation of the deltoid

Answer 23

Axillary nerve

Question 24

What is the action of the deltoid

Answer 24

Anterior fibers= flex the arm. Posterior fibers= extend the arm. Middle fibers= major abductors of the arm (takes over from the supraspinatous after 15 degrees)

Question 25

What is the origin of the trapezius

Answer 25

Skull, ligamentum nuchae and spinous processes of C7-T12

Question 26

What is the insertion of the trapezius

Answer 26

Clavicle, acromion and the scapula spine

Question 27

What is the innervation of the trapezius

Answer 27

Motor innervation from the accessory nerve. Proprioception fibres from C3 and C4 spinal nerves

Question 28

What is the action of the trapezius

Answer 28

Upper fibers= elevate the scapula and rotate it during abduction of the arm. Middle fibers= retract the scapula. Lower fibers= pull the scapula inferiorly