muscles of the shoulder

Question 1

what are the intrinsic muscles of the shoulder?

Answer 1

• deltoid
• teres major
• rotator cuff muscles

Question 2

what are the rotator cuff muscles?

Answer 2

• subscapularis
• supraspinatus
• infraspinatus
• teres minor

Question 3

1. what is the origin of deltoid?
2. what is the insertion of deltoid?
3. what is the action of deltoid?
4. what is the innervation of deltoid?

Answer 3

1. scapula and clavicle
2. deltoid tuberosity
3. arm flexion and extension + abduction 15’-90’
4. axillary nerve

Question 4

1. what is the origin of teres major?
2. what is the insertion of teres major?
3. what is the action of teres major?
4. what is the innervation of teres major?

Answer 4

1. scapula
2. interubercular groove
3. adducts shoulder + medial rotation
4. lower subscapular nerve

Question 5

1. what is the origin of supraspinatus?
2. what is the insertion of supraspinatus?
3. what is the action of supraspinatus?
4. what is the innervation of supraspinatus?

Answer 5

1. supraspinous fossa
2. greater tubercle
3. abducts 15’
4. suprascapular nerve

Question 6

1. what is the origin of infraspinatus?
2. what is the insertion of infraspinatus?
3. what is the action of infraspinatus?
4. what is the innervation of infraspinatus?

Answer 6

1. infraspinous fossa
2. greater tubercle of humerus
3. lateral rotation
4. suprascapular nerve

Question 7

1. what is the origin of teres minor?
2. what is the insertion of teres minor?
3. what is the action of teres minor?
4. what is the innervation of teres minor?

Answer 7

1. posterior scapula
2. greater tubercle of humerus
3. lateral rotation
4. axillary nerve

Question 8

1. what is the origin of subscapularis?
2. what is the insertion of subscapularis?
3. what is the action of subscapularis?
4. what is the innervation of subscapularis?

Answer 8

1. subscapular fossa
2. lesser tubercle of humerus
3. medial rotation
4. upper and lower subscapular nerve

Question 9

what are the extrinsic muscles of the shoulder?

Answer 9

• trapezius
• latissimus dorsi

Question 10

1. what is the origin of trapezius?
2. what is the insertion of trapezius?
3. what is the action of trapezius?
4. what is the innervation of trapezius?

Answer 10

1. skull, nuchal ligament, C7 - T12
2. scapula spine, acromion and clavicle
3. rotate scapular during abduction from 90’-190’
4. accessory nerve

Question 11

what is the origin of the latissimus dorsi?
what is the insertion of the latissimus dorsi?
what is the action of the latissimus dorsi?
what is the innervation of the latissimus dorsi?

Answer 11

1. T6-T12, iliac crest
2. intertubercular sulcus
3. upper limb extension, adduction 90’-180’ + medial rotation
4. thoracodorsal nerve

Question 12

what are the deep extrinsic muscles of the shoulder?

Answer 12

• levator scapulae
• rhomboid major
• rhomboid minor

Question 13

1. what is the origin of levator scapulae?
2. what is the insertion of levator scapulae?
3. what is the action of levator scapulae?
4. what is the innervation of levator scapulae?

Answer 13

1. transverse process of C1-4
2. medial border of scapula
3. elevates scapula
4. dorsal scapular nerve

Question 14

1. what is the origin of rhomboid minor?
2. what is the insertion of rhomboid minor?
3. what is the action of rhomboid minor?
4. what is the innervation of rhomboid minor?

Answer 14

1. C7-T1
2. medial border of scapula at level of spine of scapula
3. retracts scapula and rotates the medial border + assists in returning the scapula to anatomical position following abduction of arm above 90’
4. dorsal scapular nerve

Question 15

1. what is the origin of rhomboid major?
2. what is the insertion of rhomboid major?
3. what is the action of rhomboid major?
4. what is the innervation of rhomboid major?

Answer 15

1. T2-T5
2. medial border of scapula between scapular spine and inferior angle of scapula
3. dorsal scapular nerve
4. same as rhomboid minor