Organisation of nerves in thorax

Question 1

Where do somatic nerves innervate?

Answer 1

Skin and skeletal muscles

Question 2

Where do autonomic/visceral nerves innervate?

Answer 2

Organs, smooth muscle

Question 3

What are the functions of somatic spinal nerves?

Answer 3

Motor - skeletal muscle only

Sensory to body wall NOT viscera

Question 4

What do segmental nerves combine to?

Answer 4

Plexi - supply specialised areas

Question 5

What type of innervation enters the posterior dorsal horn?

Answer 5

Sensory

Question 6

What type of innervation leaves the ventral horn?

Answer 6

Motor - to muscles

Question 7

What is the difference between the posterior root and ramus?

Answer 7

Root: Sensory nerves
Ramus: Post. has sensory and motor nerves and Ant. has all others (skin/muscle)

Question 8

What is a dermatome?

Answer 8

Area of skin which is supplied by a single spinal nerve on one side/from a single spinal cord

Question 9

What is a myotome?

Answer 9

Part of skeletal muscle supplied by a single spinal nerve on one side/ from single spinal cord level

Question 10

What are spinal levels?

Answer 10

The levels on innervation which the spinal nerves innervate

Question 11

What spinal levels innervate the arm?

Answer 11

C5-8 and T1

Question 12

Why is T1 spinal level relevant?

Answer 12

Cardiac referred pain

Question 13

Why is T3 spinal level relevant?

Answer 13

3rd and 4th intercostal space

Question 14

Why is T4 spinal level relavant?

Answer 14

Nipple line, 4-5th interspace

Question 15

Why T6 spinal level relevant?

Answer 15

Xiphoid process

Question 16

Why is T10 spinal level relevant?

Answer 16

Navel

Question 17

Why is T12 spinal level relevant?

Answer 17

Pubis

Question 18

Where do IC nerves originate?

Answer 18

Only from spinal cord - so can be spinal or segmental - anterior 1ry rami

Question 19

Where are IC nerves present in the thorax?

Answer 19

Under the ridge of the ribs, between the innermost and internal layers

Question 20

How many IC nerves do we have?

Answer 20

11 pairs and 1 subcostal

Question 21

What kind of innervation do the IC muscles carry?

Answer 21

Both motor and sensory

Question 22

Where does the lateral cutaneous branch of IC nerves supply?

Answer 22

The anterior and posterior IC spaces, supplies skin

Question 23

Where does the anterior cutaneous branch of IC nerves supply?

Answer 23

The lateral and medial IC spaces, including skin outside of chest wall

Question 24

What nerves supply the IC muscles?

Answer 24

The IC nerves from the anterior ramus

Question 25

At which level does the IVC cross the diaphragm?

Answer 25

T8

Question 26

What does the phrenic nerve motor fibres supply?

Answer 26

Skeletal muscle of the diaphragm

Question 27

Where are the phrenic nerves derived from?

Answer 27

Anterior Rami of C3-5

Question 28

What kind of nerves are the phrenics?

Answer 28

Somatic so no autonomical function or visceral distribution

Question 29

What do the sensory fibres of the phrenic supply?

Answer 29

Central diaphragm, pleural covering, mediastinal pleura and pericardium (peritoneum on inf surface of diaphragm)

Question 30

Where do sympathetic nerves have cell bodies?

Answer 30

Thoraco-lumbar cord

Question 31

How do the symp nerves reach their destination?

Answer 31

Travel with vessels

Question 32

Where do the autonomic motor nerves innervate?

Answer 32

Cardiac muscle, smooth muscle and glands

Question 33

Where do the autonomic sensory nerves innervate?

Answer 33

Visceral organs

Question 34

Where does the parasympathetic division originate from?

Answer 34

Brainstem CNIII, VII, IX, X and S2-4 - craniosacral

Question 35

Where does the sympathetic division originate from?

Answer 35

T1-L2

Question 36

Where do sympathetic pathways to body wall synapse?

Answer 36

In ganglia of sympathetic trunk

Question 37

Where do symp pathways to viscera synapse?

Answer 37

In unpaired ganglia

Question 38

What do the sympathetic trunks do?

Answer 38

They take fibres up or down the body

Question 39

What is the intermediate/lateral horn?

Answer 39

Place where efferent cell bodies send out signals to be relayed

Question 40

What happens when the nerve gets to the paravertebral ganglion?

Answer 40

Either synapse onto a different nerve and ride on spinal nerve (blood vessels) OR to prevertebral ganglion to synapse on viscera OR transmitted up or down symp trunk and then synapse

Question 41

What symp nerve supplies the brain?

Answer 41

T1

Question 42

Where is there not a lateral horn?

Answer 42

Outside T1, superior to T1 and inferior L2

Question 43

Where do the symp trunks receive branches from?

Answer 43

T1-L2

Question 44

What is the role of the symp trunks?

Answer 44

Distribute symp nerves to smooth muscle, glands throughout the body

Question 45

What does the symp trunk bring back to CNS from viscera?

Answer 45

Pain fibres

Question 46

What are spanchnic nerves?

Answer 46

Bundle of fibres from lower than T5-12 that reach the abdomen

Question 47

What are the important parasymp nerves?

Answer 47

Vagus (CNX) which supplies viscera of thorax and abdomen

Question 48

What is the path of the vagus?

Answer 48

Emerges through jugular foramina to thorax, through diaphragm and to supply the abdomen

Question 49

Where is the biggest outflow of symp system?

Answer 49

T1 - efferents can make way up to head or to heart and pulmonary plexi

Question 50

What are the names of the presymp ganglia to the heart and lungs?

Answer 50

Superior, middle and inferior ganglia

Question 51

Where are many of the synapses located for the symp nerves to heart and lungs?

Answer 51

Micro-ganglia in pulm and cardiac plexi rather than trunk ganglia

Question 52

What are the functions of symp and parasymp nerves in pulm plexus?

Answer 52

Symp: dilate bronchioles | Parasymp (Vagus) constricts bronchioles

Question 53

What are the functions of symp and parasymp nerves in cardiac plexus to do with the heart (efferents)?

Answer 53

Symp: ^ HR and force of contraction Parasymp: decrease HR via pacemaker tissue and constrict coronary arteries

Question 54

What are the enlargements present on the plexus?

Answer 54

Where post-ganglionic nerves are located

Question 55

Where is the vagus nerve located?

Answer 55

Anterior to aortic arch

Question 56

What is the path of the left recurrent laryngeal nerve?

Answer 56

Comes down and wraps around aorta and then moves back up again to larynx

Question 57

What is the path of the right recurrent laryngeal nerve?

Answer 57

Comes down and wraps around right subclavian artery

Question 58

How many branches does the vagus nerve have?

Answer 58

Left and right

Question 59

What eventually happens to the vagus nerve?

Answer 59

Forms the oesophageal plexus

Question 60

Where are the oesophageal plexus located?

Answer 60

Either anterior (left vagus) or posterior (right vagus) side of oesophagus

Question 61

What is the function of the parasymp and symp nerves in the cardiac plexus to do with relaying (afferents)?

Answer 61

Symp: Relay pain sensations from heart Parasymp: Relay BP and chem info from heart

Question 62

Where does the deep cardiac plexus sit?

Answer 62

Between the aortic arch and trachea

Question 63

Where does the superficial cardiac plexus sit?

Answer 63

In front of the aortic arch

Question 64

What does the cardiac plexus do?

Answer 64

Distribute nerves to heart so opposing actions can occur

Question 65

Where does cardiac visceral pain relay back to?

Answer 65

Tends to relay back from heart to spinal cord T1-4

Question 66

Why is different pain felt between pericardium and heart?

Answer 66

Pericardium supplied by somatic phrenic nerves to C3-5 and cardiac pain supplied back to spinal cord to T1-4

Question 67

Where does CNX arise?

Answer 67

Medulla and leaves skull through jugular formaina

Question 68

What vessel does CNX follow from brain?

Answer 68

Common carotid artery (posterolateral)

Question 69

How does the left vagus pass by the lungs?

Answer 69

Crosses ant to aortic arch and posterior to left hilum

Question 70

How does right vagus pass by lungs?

Answer 70

Crosses posterior to right lung root

Question 71

What happens to the vagus after the oesophageal plexi?

Answer 71

Separate to form ant and post oesophageal/gastric nerves (cross diaphragm at T10)

Question 72

What is the function of the parasymp and symp nerves in the oesophageal plexus to do with relaying (afferents)?

Answer 72

Symp: Pain sensations from oesophagus Parasymp: Senses normal physiological info from oesophagus

Question 73

What are the parasymp branches of vagus?

Answer 73

To chest and abdomen - control smooth and cardiac muscle, glands)

Question 74

What do the parasymp NOT supply?

Answer 74

Blood vessels

Question 75

What type of nerves are the recurrent laryngeal nerves?

Answer 75

NOT parasymp - Somatic (supplies most skeletal muscles of larynx)

Question 76

Where does vagus get a large sensory content?

Answer 76

From gut and lungs (enteroreceptor)

Question 77

What do the plexi receive as well as parasymp nerves?

Answer 77

Symp fibres which are distributed via these plexi into heart and lungs/abdomen

Question 78

What is the enteric NS?

Answer 78

Plexus of ganglia and axons within the oesophageal wall

Question 79

What is the function of the intrinsic nerves of the oesophagus?

Answer 79

Coordinates the activity of oesophagus and can be up/down-regulated by autonomic nerves

Question 80

Compare the positions of phrenic vs vagus

Answer 80

Phrenic is further anteriorally than the vagus