Back muscles

Question 1

2 bones that extrinsic back muscles usually act on

Answer 1

humurus and scapula

Question 2

2 general innervation of extrinsic back muscle

Answer 2

brachial plexus and ventral rami

Question 3

innervation of intrinsic back muscle

Answer 3

dorsal rami

Question 4

on which bone does intrinsic back muscle act on ?

Answer 4

vertebral column

Question 5

2 bones involved in shoulder girdle

Answer 5

clavicle and scapula

Question 6

2 joints involved in shoulder girdle

Answer 6

acromicoclavicular and sternoclavicular

Question 7

2 bones involved in shoulder joint

Answer 7

glenoid cavity of scapula

head of humerus

Question 8

Hilton’s law

Answer 8

a nerve that supplies the muscle moving a joint will also provide sensory supply to the joint.

Question 9

Insertion and action of trapezius (3 actions)

Answer 9

spine of scapula 
thus acting on scapula 
1. Adduction of scapula (retraction)
2. elevation and depression of scapula
3. raise arm above horizontal level

Question 10

innervation of trapezium

Answer 10

spinal accessory nerve (CN XI)

Question 11

Insertion and action of latissimus dorsi

Answer 11

insertion : medial side of humerus
thus acts on humerus
1. adduction of humerus
2. medial rotation of humerus
3. extension of humerus

Question 12

innervation of latissimus dorsi

Answer 12

thoracodorsal nerve

Question 13

Insertion and action of rhomboid

Answer 13

acts on scapula

- adducts/retract scapula

Question 14

innervation of rhomboid

Answer 14

dorsal scapular nerve

Question 15

Insertion and action levator scapulae

Answer 15

elevate scapula

Question 16

innervation of levator scapulae

Answer 16

dorsal scapular nerve

Question 17

use of serratus posterior superior and inferior

Answer 17

acessory muscles for respiration

Question 18

5 scapular muscles

Answer 18

deltoid
supraspinatus
infraspinatus
teres minor and major

Question 19

action of supraspinatous

Answer 19

inserted at greater tubercle of humerus

so it abducts humerus (initiation of abduction)

Question 20

innervation of supraspinatous

Answer 20

suprascapular nerve

Question 21

action of infraspinatus

Answer 21

lateral rotation of humerus

Question 22

innervation of infraspinatus

Answer 22

suprascapular nerve

Question 23

action of teres minor

Answer 23

lateral rotation of humerus

Question 24

innervation of teres minor

Answer 24

axillary nerve

Question 25

action of teres major

Answer 25

``` inserted into medial side of humerus so - adduction of humerus - medial rotation - extension of humerus ```

Question 26

innervation of teres major

Answer 26

lower subscapular nerve

Question 27

action of deltoid muscle

Answer 27

abduction (20~90 degree of abduction)

Question 28

innervation of deltoid

Answer 28

axillary nerve

Question 29

Pectoralis major action

Answer 29

adduction of humerus medial rotation flexion

Question 30

innervation of petoralis major

Answer 30

medial & lateral pectoral nerve

Question 31

pectoralis minor action

Answer 31

stabilize scapula

Question 32

innervation of petoralis minor

Answer 32

medial & lateral pectoral nerve

Question 33

serratus anterior action

Answer 33

abducts scapula

Question 34

innervation of serratus anterior action

Answer 34

long thoracic nerve

Question 35

action of splenius capitis and cervicis (2)

Answer 35

bilateral contraction - extension of neck unilateral contraction - lateral flexion and rotation of head * for rotation we need oblique muscle.

Question 36

3 muscles in erector spinae group

Answer 36

- spinalis - longissimus - iliocostalis

Question 37

action of erecor spinae group (2)

Answer 37

bilateral contraction : extension of trunk | unilateral contraction : lateral flexion of trunk

Question 38

3 muscles in transversospinalis group

Answer 38

- semispinalis (4-6 segments) - rotatores (1-2 segments) - multifidus ( 2-4 segments)

Question 39

roles of transversospinalis group

Answer 39

stabilize vertebral column

Question 40

Action of transversospinalis group(2)

Answer 40

bilateral contraction : extend trunk, neck, head | unilateral contraction : rotate to opposite side and laterally flex

Question 41

Triangle of ausculation

Answer 41

medial : trapezius lateral : medial border of scapula inferior : latissimus dorsi * best place to auscultate heart and lung sounds on the back

Question 42

triangle of petit

Answer 42

also called lumbar triangle - site of lumbar herniation (herniation of intestinal content) - between lateral, external oblique and iliac crest