Pectoral and Shoulder Region

Question 1

What are the superficial extrinsic muscles of the shoulder?

Answer 1

Trapezius and latissimus dorsi

Question 2

What is the origin and attachments of the trapezius?

Answer 2

Origin - skull, muchal ligament and spinous process of C7-T12
Attaches to clavicle, acromion and scapula spine

Question 3

What is the action of the trapezius muscle?

Answer 3

Upper fibres - elevate scapula and rotate it during abduction
Middle fibres - retract scapula
Lower fibres - pulls scapula inferiorly

Question 4

What is the origin and attachment of the latissimus dorsi?

Answer 4

Origins - spinous process of T7-12, iliac crest, thoracolumbar fascia and scapular spine
Attachment - intertubercular sulcus of the humerus

Question 5

What is the action of the latissimus dorsi?

Answer 5

Extension, adduction and medial rotation

Question 6

What are the deep intrinsic muscles of the shoulder?

Answer 6

Levator scapula
Rhomboid major and minor

Question 7

What is the attachment of the levator scapula and rhomboid major + minor?

Answer 7

Medial border of the scapula

Question 8

What is the action of the rhomboids on the shoulder?

Answer 8

Retracts and rotates scapula

Question 9

What are the origins and insertions of the deltoid?

Answer 9

Origin - spine of scapula, lateral 1/3 of clavicle and acromion
Insertion - deltoid tuberosity of the humerus

Question 10

What is the origin and attachment of the teres major?

Answer 10

Origin - posterior surface of inferior angle of scapula
Insertion - medial lip of intertubercular groove of humerus

Question 11

What are the actions of the deltoid muscle?

Answer 11

Anterior fibres - flex and medially rotate
Posterior fibres - extend and laterally rotate
Medial fibres - main adductor of arm

Question 12

What is the action of the teres major?

Answer 12

Adduction, extension and medial rotation

Question 13

What is the innervation of the teres major?

Answer 13

Lower subscapular nerve

Question 14

What are the rotator cuff muscles?

Answer 14

Suprascapular, infraspinatus, subscapularis and teres minor

Question 15

What is the insertions of the rotator cuff muscles?

Answer 15

Supraspinatus, infraspinatus and teres minor - greater tubercle of the humerus
Subscapularis - lesser tubercle of humerus

Question 16

What is the action of the supraspinatus?

Answer 16

Abduction of UL
Performs the 0-15 degrees of abduction and assists with the deltoid until 90 degrees

Question 17

What is the action of the infraspinatus?

Answer 17

Laterally rotates the arm

Question 18

What is the action of the subscapularis?

Answer 18

Medially rotates the arm

Question 19

What is the action of the teres minor?

Answer 19

Laterally rotates the arm

Question 20

What is the innervation of the teres minor?

Answer 20

Axillary nerve

Question 21

What is the innervation of the subscapularis and infraspinatus?

Answer 21

Suprascapular nerves

Question 22

What is the origin and insertion of the pectoralis major?

Answer 22

Origin - anterior surface of medial clavicle , sternum, superior 6 costal cartilages and aponeurosis of external oblique muscle
Insertion - intertubercular sulcus of the humerus

Question 23

What is the origin and insertion of the pectoralis minor?

Answer 23

Origin - 3-5th rib
Insertion - coracoid process of scapula

Question 24

What is the origin and insertion of serratus anterior?

Answer 24

Origins - lateral ribs 1-8
Insertion - costal surface of medial border of scapula

Question 25

What is the action of the pectoralis major?

Answer 25

Adducts and medially rotates UL and draws scapula anterior + inferiorly

Question 26

What is the action of the pectoralis minor?

Answer 26

Stabilises the scapula

Question 27

What is the action of the serratus anterior?

Answer 27

Holds scapula against rib cage and rotates scapula for upward movement

Question 28

What muscles are involved in extension of the shoulder joint?

Answer 28

Latissimus dorsi, deltoid and teres major

Question 29

What muscles are involved in flexion of the shoulder joint?

Answer 29

Pectoralis major, anterior deltoid and coracobrachialis Weak flexion from biceps brachii

Question 30

What muscles are involved in adduction of the shoulder joint?

Answer 30

Pectoralis major, latissimus dorsi and teres major

Question 31

What muscles are involved in abduction of the shoulder joint?

Answer 31

First 15 degrees - supraspinatus 15-90 degrees - deltoid After 90 degrees - trapezius and serratus anterior

Question 32

What muscles are involved in internal rotation of the shoulder joint?

Answer 32

Subscapularis, teres major, pectoralis major, latissimus dorsi and anterior deltoid

Question 33

What muscles are involved in external rotation of the shoulder joint?

Answer 33

Infraspinatus and teres minor