Anatomy of nerve plexuses

Question 1

What does the peripheral nervous system consist of

Answer 1

12 pairs of cranial nerves, 31 pairs of spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral plus coccygeal nerve)

Question 2

What is the somatic nervous system

Answer 2

Voluntary nervous system which provides general sensory and motor innervations to body except viscera in body cavities, smooth muscle and glands

Question 3

What does the dorsal (posterior) ramus supply

Answer 3

Dorsal 1/3 of the body wall (not limb)
-supplies deep muscles of back (extensor muscles of the vertebral column) and overlying skin and synovial joints of vertebral column

Question 4

What does the ventral (anterior) ramus supply

Answer 4

Ventral 2/3 of the body wall, including limbs

Question 5

What is a primary ramus

Answer 5

Branch of a spinal nerve

Question 6

Are ventral or dorsal rami larger

Answer 6

Ventral rami and are more clinically important

Question 7

What is a feature of all spinal nerves in relation to their rami

Answer 7

Their ANTERIOR rami branch and rejoin forming nerve plexuses

Question 8

Where do the plexuses formed from anterior rami occur in

Answer 8

Cervical, brachial, lumbar and sacral regions

Question 9

How can nerve fibres regroup within a plexus

Answer 9

• Branches can contain fibres from more than one spinal level (convergence)
• Given spinal level may contribute to more than one branch (divergence)

Question 10

Why does damage to one spinal segment not usually lead to complete loss of function or sensation

Answer 10

Because of regrouping

Question 11

What are the five groups of ventral rami and their spinal root value

Answer 11

Cervical plexus (C1-C5)
Brachial plexus (C5-T1)
Nerves of the trunk (T1-L1)
Lumbosacral plexus (L1-S3)
Sacrococcygeal plexus (S3-S5)

Question 12

What does the cervical plexus supply

Answer 12

Head and neck

Question 13

What does the brachial plexus supply

Answer 13

Upper limb

Question 14

What do the nerves of the trunk supply

Answer 14

Trunk

Question 15

What does the lumbosacral plexus supply

Answer 15

Trunk and lower limb

Question 16

What does the sacrococcygeal plexus supply

Answer 16

Pelvis and lower trunk

Question 17

List cutaneous cervical spinal segments which contribute to the cervical plexus and their spinal root value

Answer 17

Lesser occipital- C2/(C3)
Greater auricular- C2/C3
Transverse cervical cutaneous- C2/C3
Supraclavicular- C3/C4

Question 18

List motor (deep) cervical spinal segments which contribute to the cervical plexus and their spinal root value

Answer 18

Ansa cervicalis - C1-C3
Phrenic - C3-C5
Other muscular branches - C1-C5

Question 19

What does the lesser occipital nerve supply

Answer 19

Skin of neck and scalp posteriosuperior to auricle

Question 20

What does the greater auricular nerve supply

Answer 20

Skin over parotid gland, part of the auricle, skin from angle of mandible to mastoid process

Question 21

What does the transverse cervical nerve supply

Answer 21

Skin of anterior cervical region

Question 22

What do the supraclavicular nerves supply

Answer 22

Branches to skin of neck and over clavicle to skin of shoulder

Question 23

What is the brachial plexus divided into

Answer 23

Roots
Trunks
Divisions
Cords
Branches

Question 24

what are the roots of the brachial plexus

Answer 24

C5, C6, C7, C8, T1

Question 25

Which roots converge together to form the upper trunk

Answer 25

C5 and C6

Question 26

Which roots converge to form the middle trunk

Answer 26

None, it is just C7

Question 27

Which root converge to form the lower trunk

Answer 27

C8 and T1

Question 28

What are the divisions of the trunks

Answer 28

Anterior and posterior divisions

Question 29

What is the posterior division

Answer 29

All three trunks converge to make the posterior divisions

Question 30

What are the anterior divisions

Answer 30

Upper and middle divisions converge and lower division is by itself

Question 31

What are the different cords the brachial plexus

Answer 31

Lateral Posterior Medial

Question 32

What branches does the posterior cord have

Answer 32

Axillary and radial

Question 33

What branch does the lateral cord have

Answer 33

Musculocutaneous

Question 34

What branch does the medial cord have

Answer 34

Ulnar

Question 35

Where does the median branch come from

Answer 35

Lateral and medial cord (looks like an M)

Question 36

What is the spinal root value of the musculocutaneous nerve

Answer 36

C5-C7

Question 37

What is the spinal root value of the median nerve

Answer 37

C5-C7 | C8-T1

Question 38

What is the spinal root value of the ulnar nerve

Answer 38

C8-T1

Question 39

What is the spinal root value of the radial nerve

Answer 39

C5-T1

Question 40

What is the spinal root value of the axillary nerve

Answer 40

C5,C6

Question 41

What is the spinal root value of the dorsal scapular

Answer 41

C5

Question 42

What is the spinal root value of the subscapular: upper and lower

Answer 42

C5,C6

Question 43

Spinal root value of suprascapular nerve

Answer 43

C5,C6

Question 44

Spinal root value value of long thoracic nerve

Answer 44

C5-C7

Question 45

Spinal root value of pectoral: medial and lateral nerve

Answer 45

C5-T1

Question 46

Spinal root value of thoracodorsal nerve

Answer 46

C7,C8

Question 47

What is the autonomic plexuses formed by

Answer 47

Sympathetic and parasympathetic nerves

Question 48

What do sympathetic and parasympathetic nerves to viscera form

Answer 48

Series of plexuses anterior to vertebral bodies (in or on the viscera or associated vessels)

Question 49

What preverterbal autonomic plexuses are especially large

Answer 49

Cardiac plexus Pulmonary plexus Coeliac plexus Hypogastric plexus

Question 50

What does the cardiac plexus innervate

Answer 50

The heart

Question 51

What do the sympathetic nerves arise from

Answer 51

cervical and upper thoracic parts of sympathetic trunk

Question 52

What does the parasympathetic supply derive from

Answer 52

Vagus nerve

Question 53

What do the sympathetic nerves and parasympathetic nerves contribute to

Answer 53

Oesophageal plexus

Question 54

What do sympathetic fibres do -What are the afferent fibres associated with

Answer 54

Speed up heart and dilate coronary arteries -Pain

Question 55

Want do parasympathetic fibres do -What are the afferent fibres associated with

Answer 55

Reduce heart rate and constrict arteries -Afferent fibres take part in cardiovascular reflexes

Question 56

What does the pulmonary plexus surround

Answer 56

Lung root and has branches from the upper thoracic sympathetic trunk and vagus nerve