Peripheral Nervous System

Question 1

Components of the PNS

Answer 1

1. Cranial Nerves
2. Spinal Nerves
3. Autonomic Nervous System (Sympathetic and Parasympathetic)
4. Enteric

Question 2

Spinal Nerve System

Answer 2

• Segmental Dorsal Rami – deep axial muscles/posterior skin along spinal column
• Segmental Ventral Rami – limbs and body wall
  – Cervical Plexus
  – Brachial Plexus
  – Intercostal nerves
  – Lumbosacral Plexus

Question 3

Segmental Dorsi Rami

Some have names, some don’t

Answer 3

Subocciptal Nerve (C1)
Greater Occipital Nerve (C2)
Third Occipital Nerve (C3)
C4 – T12 Dorsal Rami
L1-L3 Superior Cluneal Nerves
L4, L5 Dorsal Rami
S1-S3 Middle Cluneal Nerves
S4 – Cx2 Dorsal Rami
- primarily innervate posterior skin and deep spine muscles, and facet joints

C1- intervation may present as: Cranial facial pain, headaches

Question 4

How to identify type of vertebrae

Answer 4

• Angle of the capsule of the articular process
• Look at the nerves in the spinal cord

Dorsal: Nerve goes to facet joint and muscle (multifidus) in image

Question 5

Cervical Plexus

Answer 5

• C1 – C5
• Ansa Cervicalis (C1 – C3)
• Cutaneous Nerves (C2 – C4)
• Phrenic Nerve (C3-C5); Diaphram

Specific twigs that send little twigs out to muscles
Ansa Cervicalis: thyroid muscles

Question 6

Brachial Plexus

Answer 6

C5-T1
RTDCB - MARMU
Splits into 3 anterior and 3 posterior division

Question 7

Anterior Dividion of BP will innervate

Answer 7

Developmentally Ventral Structures

Question 8

Posterior Division of BP will innervate

Answer 8

Developmentally Dorsal Structures

Question 9

The three cords are names based off position to Axillary A.

Answer 9

The Divisions Join to form Three Cords – named for relation to axillary artery – lateral, posterior, medial

Question 10

Lateral Cord

Answer 10

From Anterior Divisions (to ventral structures, mostly flexors!)
Lateral Pectoral Nerve (C5-C8)
Musculocutaneous Nerve (C5-C7)
Lateral Root to the Median Nerve (C6 & C7)

Median Nerve C6-T1

Question 11

Medial Cord

Answer 11

From Anterior Divisions (also to ventral structures, mostly flexors)
Medial Pectoral Nerve (C7 – T1)
Medial Brachial Cutaneous Nerve (C8 & T1)
Medial Antebrachial Cutaneous Nerve (C8 & T1)
Medial Root to the Median Nerve (C8 & T1)
Ulnar Nerve (C8 & T1)

Median Nerve C6-T1

Question 12

Posterior Cord

Answer 12

From Posterior Divisions (to dorsal structures, mostly extensors)
Upper Subscapular Nerve (C5 & C6)
Thoracodorsal Nerve (C6, C7 & C8)
Lower Subscapular Nerve (C5 & C6)
Axillary Nerve (C5 & C6)
Radial Nerve (C5, C6, C7 & C8)

Question 13

Injuries above the plexus

Answer 13

Dermatome/Myotome Charts

Question 14

Injuries below, use

Answer 14

peripheral distribution charts

Question 15

Injury occuring in the middle of the plexus present as

Answer 15

random; individual situation

Question 16

Upper Arm Compartmentalization - Anterior Arm

Answer 16

Flexes Shoulder and Elbow
Anterior Divisions
Musculocutaneous Nerve
C5, C6, C7

Question 17

Upper Arm Compartmentalization - Posterior Arm

Answer 17

Extends Elbow
Posterior Divisions
Radial Nerve
C7 & C8

Question 18

UA Compart - Anterior Forearm

Answer 18

Flexes Wrist and Fingers
Anterior Divisions
Median Nerve (Mostly)
C6, C7 & C8

Question 19

UA Compart - Posterior Forearm

Answer 19

Extends Wrist and Fingers
Posterior Divisions
Posterior Interosseous Nerve (Mostly)
C7 & C8

Question 20

UL Compart - Intrinsic Hand

Answer 20

Abducts/Adducts Fingers
Anterior Divisions
Ulnar Nerve (Mostly)
C8 & T1

Question 21

Lumbar Plexus

Answer 21

• Subcostal Nerve – T12
• Iliohypogastric Nerve – L1
• Ilioinguinal Nerve – L1
• Genitofemoral Nerve – L1 & L2
• Lateral Femoral Cutaneous Nerve – L2 & L3
• Femoral Nerve – L2, L3, L4 (Posterior Divisions)
• Obturator Nerve – L2, L3, L4 (Anterior Divisions)
• Lumbosacral Trunk – L4 & L5

T12-L5

LFC: Commonly gets compressed with pregnancy, obesity, and tight clothes

Question 22

Sacral Plexus

Answer 22

• Superior Gluteal Nerve – L4, L5, S1 (Posterior Divisions)
• Nerve to Quadratus Femoris – L4, L5, S1 (Anterior Divisions)
• Inferior Gluteal Nerve – L5, S1, S2 (Posterior Divisions)
• Nerve to Obturator Internus – L5, S1, S2 (Anterior Divisions)
• Posterior Femoral Cutaneous Nerve – S1, S2, S3
• Pudendal Nerve – S2, S3, S4
• Pelvic Parasympathetics – S2, S3, S4
• Sciatic Nerve (Tibial and Fibular Nerve Combined)
  – Common Fibular Nerve – L4, L5, S1, S2 (Posterior Divisions)
  – Tibial Nerve – L4, L5, S1, S2, S3 (Anterior Divisions)

Question 23

Muscles and Nerve Innervation - Lumbosacral

Answer 23

Question 24

Developmental in the LE has rotation so…

Answer 24

what started out as dorsal is now anterior…i.e. the posterior divisions of the plexus innervate anterior compartments

Question 25

LL Comp - Anterior Thigh

Answer 25

Flexes Thigh and Extends Leg Posterior Divisions Femoral Nerve L2, L3, L4

Question 26

LL Comp - Medial Thigh

Answer 26

Adducts and Flexes Thigh Anterior Divisions Obturator Nerve L2, L3, L4

Question 27

LL Comp - Posterior Thigh

Answer 27

Extends Thigh and Flexes Leg Anterior Divisions Tibial Nerve L4, L5, S1

Question 28

LL Comp - Ant Lower Leg

Answer 28

Dorsiflexes Foot Posterior Divisions Deep Fibular Nerve L4, L5, S1, S2

Question 29

LL Comp - Lateral Lower Leg

Answer 29

Everts Foot Posterior Divisions Superficial Fibular Nerve L5, S1, S2

Question 30

LL Comp - Posterior Lower Leg

Answer 30

Plantarflexes Foot Anterior Divisions Tibial Nerve S1, S2

Question 31

Anterior Interossi N. is

Answer 31

a terminal branch of the median nerve and is only motor innervation and is in the hand.

Question 32

The PNS's major function is..

Answer 32

Signal transduction

Question 33

What forms the basis for neurodynamic assessment and treatment?

Answer 33

The idea that the system is continuous, and nerves like space, movement, and blood flow

Question 34

Effectors =

Answer 34

muscles and glands

Question 35

Receptors =

Answer 35

Energy biotransducers, they take energy from the environment, and transduce them to signals

Question 36

Receptors: Adaptation, afferent, proprioceptove function

Answer 36

Question 37

Receptive Fields for sensation

Answer 37

Vary depending on location in body. Finger: Good at localizing, lots of sensory nerves Low Back: Not good, less overlap of sensory nerves.

Question 38

Why does the nervous system need to expand?

Answer 38

* Demand on length of nerves changes depending on position. * Ex: spinal canal is 7-10 cm longer in flexion vs extension. * Nerves are not elastic, they slide, fold, and twist

Question 39

Peripheral nerve structure

Answer 39

* Peripheral nerves are sheathed, have a blood supply (Vasa Nervosum) and innervation (Nervi Nervosum) * Sheath provides protection and nutrition * **Nerves are bloodthirsty!!** * Cells also depend on axoplasmic flow for functional processes – movement of organelles, proteins, etc. (similar to cytoplasm) * Flow is movement dependent * **Movement = blood and axoplasmic flow**

Question 40

Peripheral nerves need:

Answer 40

Space, movement and blood Missing one of these will result in them being symptomatic (pins and needles, weakness, etc.)

Question 41

peripheral nerve lesions (compression)

Answer 41

* Often see **sensory changes before motor** * Susceptible to compression in tight spaces or near hard surfaces

Question 42

Pressure and spine

Answer 42

* Intervertebral foramen: nerves exit the spine from here; Common place of compressure * Cervical: exit above veretbrae; Ex: C6 nerve root exist C5-C6 * Thoracic: Extremely rare. * Lumbar: Spinal Cord ends at L1-L2, therefore peripheral nerves branch and go through spinal cord to exit. Ex: L3 N, exists below L3 Vertebrae at the top of the foramen. With a lesion there L3 N has no issues but L4 could be compressed. * Cervical Ex: In the spinal cord tumor in at C7, leads to hyperreflexia in the legs as it is an UMN lesion. Also leads to myotome and dermatome issues for levels of C7 and below. * Same situation but in lumbar: L3 lesion, L3 is able to leave myotome and dermatome good. L4-S4 myotome and dermatome affected.

Question 43

Below L1-L2 injury would be...

Answer 43

peripheral nerve injury

Question 44

LL Comp - Dorsal Foot

Answer 44

Supports Foot, Extends Toes Posterior Divisions Deep Fibular Nerve S1, S2

Question 45

Plantar Foot

Answer 45

Supports Foot, Flexes Toes Anterior Divisions Medial & Lateral Plantar Nerves From Tibial Nerve S2, S3