Muscles of shoulder region COPY

Question 1

Two divisions of muscles

Answer 1

Extrinsic

Intrinsic

Question 2

Extrinsic muscles

Answer 2

Originate from torso (back of trunk) and insert onto bones of shoulder (clavicle, scapula, humerus)

Question 3

Intrinsic muscles

Answer 3

Originate from scapula/clavicle and insert onto humerus

Question 4

Extrinsic muscles named

Answer 4

Superficial: trapezius and lattisimus dorsi

Deep: levator scapulae, rhomboid major and minor

Question 5

Trapezius O and I

Answer 5

O: occipital protuberance of skull, nuchal ligament, spinous processes C7-T12
I: Clavicle, acromion and spine of scapula

Question 6

Trapezius action

Answer 6

Upper fibres elevate scapula and rotate during abduction above 90 degrees
Middle fibres retract scapula
Lower fibres pull scapula inferiorly

Question 7

Trapezius innervation

Answer 7

Spinal accessory nerve (cranial nerve XI)

Proprioceptor fibres C3 C4

Question 8

test trapezius

Answer 8

Shrug shoulders while someone is pushing down on them

Question 9

Latissimus dorsi O and I

Answer 9

Deep to inferior fibres of trapezius
O: Spinous processes T6-T12, iliac crest, thoracolumbar fascia, inferior 3 ribs

I: Tendon into intertubercular sulcus of humerus

Question 10

Actions and innervation lattisimus dorsi

Answer 10

Action: extends, adducts and medially rotates the shoulder joint
Innervation: Thoracodorsal nerve

Question 11

Levator scapulae O and I

Answer 11

O: Tranverse processes C1-C4
I: Medial border of scapula

(deep to trapezius and superior to rhomboid minor)

Question 12

Innervation and action levator scapulae

Answer 12

Action: elevates scapula
Innervation: Dorsal scapular nerve

Question 13

Rhomboids

Answer 13

Rhomboid minor is superior to major but is smaller

Question 14

Rhomboid minor O and I

Answer 14

O: Spinous processes C7-T1
I: Medial border scapula

Question 15

Rhomboid minor action and innervation

Answer 15

Action: Retracts scapula rotates medial border (back to anatomical position after abduction above 90 degrees)

innervation: Dorsal scapular nerve

Question 16

Rhomboid major o and I

Answer 16

O: Spinous processes T2-T5

I - medial border scapula

Question 17

Rhomboid major actions and innervations

Answer 17

Actions: Retracts scapula, rotates medial border (glenoid fossa rotated inferiorly, helps return to anatomical position after 90 degree+ abduction)

Innervation; Dorsal scapular nerve

Question 18

Intrinsic muscles known as

Answer 18

Scapulohumeral group

Question 19

Deltoid O and I

Answer 19

o: lateral 3rd anterior border clavicle, acromion and spine of scapula
I: deltoid tuberosity on humerus

Question 20

Deltoid actions

Answer 20

Anterior fibres: Flex and medially rotate arm at shoulder
Middle fibres: abduct arm from 15-90 degrees
Posterior fibres: extend and laterally rotate arm at shoulder

Question 21

Deltoid innervation

Answer 21

Axillary nerve

Question 22

Teres major O and I

Answer 22

O; Posterior inferior angle scapula
I: Medial lip of intertubercular groove

(inferior border of quadrangular space: axillary nerve and posterior circumflex humeral artery pass)

Question 23

Teres major action and innervation

Answer 23

Action: adducts and extends arm at shoulder, medially rotates arm
Innervation: Lower subscapular nerve

(goes from posterior and inserts anteriorly)

Question 24

Rotator cuff muscles

Answer 24

Originate from scapula
Attach to humeral head
Pull humeral head into glenoid fossa

Question 25

Rotator cuffs (4)

Answer 25

SITS

Supraspinatus
Infraspinatus
Teres minor
Subscapularis

Question 26

Supraspinatus O and I

Answer 26

O: Supraspinous fossa of scapula
I: greater tubercle of humerus

Question 27

Supraspinatus action and innervation

Answer 27

A: Abducts arm first 15 degrees
I: Suprascapular nerve

Question 28

Infraspinatus O and i

Answer 28

O; Infraspinous fossa of scapula

I: Greater tubercle of humerus (between supraspinatus and teres major)

Question 29

Infraspinatus A and I

Answer 29

A: Laterally rotates arm
I: Suprascapular nerve

Question 30

Subscapularis O and I

Answer 30

O: subscapular fossa
I: LESSER tubercle of humerus

Question 31

Subscapualris A and I

Answer 31

A: medially rotates
I: Upper and lower subscapular nerves

Question 32

Teres minor O and I

Answer 32

O: Posterior scapula
I: Greater tubercle humerus

Question 33

Teres minor A and I

Answer 33

A: Laterally rotates arm
I: Axillary nerve