A&P 2.12 sacral plexus Flashcards Preview

A&P 2 > A&P 2.12 sacral plexus > Flashcards

Flashcards in A&P 2.12 sacral plexus Deck (29)
1

Sacral plexus

Sciatic nerve - main branch and largest nerve in the body

Pelvis and posterior LE entirely innervated by the branches of the sacral plexus
From ventral rami L4-S4
Composed of tibial and common fibulas nerve wrapped together in a single fascial sheath
Innervates posterior thigh and lateral leg

2

Sciatic nerve

splits at and becomes

SPLITS AT KNEE TO BECOME TIBIAL (medial - posterior) AND COMMON FIBULAR NERVES

3

Peroneal nerve

Common FIBULAR nerve

4

lumbosacrial plexus

Lumbar and sacral plexus are often considered together

5

Sciatica

Pain along the course of the sciatic nerve (from buttock down posterior and or lateral LE)
Or may be referred from trigger points (most of the time this is at least a component of the pain)

6

Sciatica may result from

A true neuralgia of the sciatic nerve by

Or trigger points located in the gluteus minimums or piriformis

7

True neuralgia

2 main causes

Pressure on roots of L5

entrapment of sciatic nerve by pisiform muscle

8

Pressure on roots of L5 by:

Herniated disc
Osteroarthritis on the lumbosacrial spine
Pressure from the uterus during Px
An improperly administered gluteal intramuscular injection

9

Trigger points

Trigger points located in the gluteus minimums or piriformis

- cause a pseudo-sciatica where there is no real disturbance to the nerve
At least partially involved in the vast majority of sciatica cases

10

Nuclei versus ganglia chart

CNS (axons - tracts - white) (cell body- nuclei - grey)

PNS (axons- nerves - white). ( cell bodies - ganglia - grey)

11

ONLY GANGLIA IN CNS IS THE

ONLY GANGLIA IN CNS IS THE BASAL GANGLIA

12

Herpes zoster

name & cause

Shingles
Caused by a VIRUS - chicken pox/varicella virus
Lies dormant in the dorsal root ganglia (meeting point for all the sensory neurons in each dermatome
If you had chicken pox, you can get shingles

13

Herpes zoster

Affects

Affects - the dendrites at the end of sensory neurons along a specific dermatome, blisters break out at nerve endings. Blisters unilaterally.

14

Herpes zoster

triggers

Triggers - stress, weakened immune system, chemotherapy

15

Herpes zoster

Symptoms

Symptoms: pain is present before outbreak, for the 2-3 weeks during outbreak, and can last for months after the lesions have healed.

16

Shingles

Meaning

Latin for belt or girdle
Describing the distribution of blisters around chest or abdomen along a single dermatomal line

17

Herpes zoster

Treatments

Treatment - anti-viral prescriptions, and will also help stave off Post Herpetic Neuralgia (painful after effects), steroids, antidepressants, anti convulsion, and topical agents

18

Post Herpetic neuralgia

Pain is the most common complication of shingles. The pain ranges from tenderness, burning, or throbbing to pain is stabbing, shooting or sharp. It can last for months to years

19

Nerve fiber repair

Mature neurons are typically thought to be incapable of cell division and cannot be replaced. Only option for healing due to damage or disease is repair of those already present.

20

Nerves can be repaired if

Damage is not too extensive
Cell body and cell membrane (neurilemma) remain intact
Scarring has not occurred

20

Stages of nerve repair

PNS ONLY

4 stages

Injury resulting in a nerve cut
WALLERIAN DEGENERATION
Remaining NEURILEMMA tunnel from the point of injury to the effector
Neuron's connection with effector is reestablished

21

Stages of nerve repair

PNS ONLY

Stage 1

Injury resulting in a nerve cut

Immediately after injury, DISTAL portion of axon degenerates, along with its myelin sheath (WALLERIAN DEGENERATION)

Remaining NEURILEMMA tunnel from the point of injury to the effector: new Schwann cells grow within a tunnel maintaining a pathway for axon regrowrh. Several growing axon sprouts appear. When one of these growing fibers reaches the tunnel, it increases its growth rate. The other sprouts eventually disappear (approximately 1mm per day)

Neuron's connection with effector is reestablished

22

Stages of nerve repair

PNS ONLY

Stage 2

Immediately after injury, DISTAL portion of axon degenerates, along with its myelin sheath (WALLERIAN DEGENERATION)

23

CNS VERSUS PNS repair

Repair in CNS is not as successful in the PNS.
Oligodendrocytes and astrocytes have an inhibiting effect on fiber growthalso the way oligodendrocytes form the myelin sheaths is different.

24

Stages of nerve repair

PNS ONLY

Stage 3

Remaining NEURILEMMA tunnel from the point of injury to the effector: new Schwann cells grow within a tunnel maintaining a pathway for axon regrowrh. Several growing axon sprouts appear. When one of these growing fibers reaches the tunnel, it increases its growth rate. The other sprouts eventually disappear (approximately 1mm per day)

25

Stages of nerve repair

PNS ONLY

Stage 4

Neuron's connection with effector is reestablished

26

WALLERIAN DEGENERATION

DISTAL portion of axon degenerates, along with its myelin sheath

27

Glial cells are capable of

Cell division

28

Quadratus lumborum

A, I, O

Unilateral: ipsilateral flexion, lateral pelvic tilt (to same side)
Bilateral: extension of the spine, fix the ribs during inhalation

O- proximal attachment: 12th rib (internal margin), TP of L1-L4

I- distal attachment: iliac crest (internal lip)