Muscles of the shoulder

Question 1

Muscles of the shoulder?

Answer 1

Deltoid (anterior, medial, posterior), pectoralis major (clavicular, sternal), latissimus dorsi, teres major, supraspinatus, infraspinatus, teres minor, subscapularis, coracobrachialis,

Question 2

Deltoid origin (anterior, medial, posterior)

Answer 2

A: lateral third of the clavicle
M: lateral end of the acromion process
P: spine of the scapula

Question 3

Deltoid insertion

Answer 3

Deltoid tuberosity (lateral aspect of the humerus)

Question 4

Anterior Deltoid action

Answer 4

Abduction, flexion, horizontal adduction, internal rotation

Question 5

Pectoralis Major origin (clavicular, sternal)

Answer 5

C: medial third of the clavicle
S: anterior lateral surface of the sternum; ribs 1-6

Question 6

Pectoralis Major insertion

Answer 6

Lateral lip of bicipital groove of humerus; “intertubercle groove”

Question 7

Pectoralis Major action (clavicular, sternal)

Answer 7

C: internal rotation, horizontal adduction, flexion, abduction (once arm is abducted to 90 degrees), adduction (with arm below 90 degrees)
S: internal rotation, horizontal adduction, extension, adduction

Question 8

Latissimus Dorsi origin

Answer 8

Spinous priocesses of T7-L5, posterior surface of the sacrum, iliac crest, and the lower three ribs (9-11)

Question 9

Latissimus Dorsi insertion

Answer 9

Medial lip of bicipital groove of humerus

Question 10

Latissimus Dorsi action

Answer 10

Extension, adduction, internal rotation, horizontal abduction

Question 11

Teres Major origin

Answer 11

Inferior angle of the scapula

Question 12

Teres Major insertion

Answer 12

Inferior anterior aspect of the lesser tubercle

Question 13

Teres Major action

Answer 13

Extension, internal rotation, adduction

Question 14

Supraspinatus origin

Answer 14

Supraspinous fossa of the scapula

Question 15

Supraspinatus insertion

Answer 15

Superior aspect greater tubercle of the humerus

Question 16

Supraspinatus action

Answer 16

Weak abduction (to 90 degrees), stabilization of the humeral head in the glenoid fossa

Question 17

Infraspinatus origin

Answer 17

Infraspinous fossa posterior surface of the scapula

Question 18

Infraspinatus insertion

Answer 18

Inferior aspect greater tubercle of humerus

Question 19

Infraspinatus action

Answer 19

External rotation, horizontal abduction, extension, stabilization of humeral head in the glenoid fossa

Question 20

Teres Minor origin

Answer 20

Posterior surface axillary border of scapula

Question 21

Teres Minor insertion

Answer 21

Posterior aspect greater tubercle of humerus

Question 22

Teres Minor action

Answer 22

External rotation, horizontal abduction, extension, stabilization of humeral head in the glenoid fossa

Question 23

Subscapularis origin

Answer 23

Subscapular fossa anterior surface of the scapula

Question 24

Subscapularis insertion

Answer 24

Lesser tubercle of the humerus

Question 25

Subscapularis action

Answer 25

Interal rotation, adduction, extension, stabilization of the humeral head in the glenoid fossa

Question 26

Coracobrachialis origin

Answer 26

Coracoid process of the scapula

Question 27

Coracobrachialis insertion

Answer 27

Medial anterior surface middle 1/3 of the humerus

Question 28

Coracobrachialis action

Answer 28

Horizontal adduction, flexion, adduction

Question 29

Medial Deltoid action

Answer 29

Shoulder abduction

Question 30

Posterior Deltoid action

Answer 30

Abduction, extension, horizontal abduction, external rotation

Question 31

What muscles stabilize the humeral head in the glenoid fossa?

Answer 31

Supraspinatus, infraspinatus, teres minor, and the subscapularis