Regional Anaesthesia Flashcards
1
Q
Nerve anatomy ?
A
- Neurons contain cell bodies, dendrites and axons
- Endoneurium is a connective tissue enveloping individual nerve fibres
- Perineurium cover fascicles formed by a bundle of nerve fibres.
- Epineurium covers bundles of perineurium
2
Q
Neurons ?
A
- Contain positive and negative charges
- The inside of the cell is negative (-90mV)
- Depolarization results in intracellular charge becoming more positive
- Sodium channels open to allow influx
- Threshold is at +35mV
- For every 3Na efflux, 2K influx
3
Q
Neurons, action potential ?
A
Read from book
4
Q
Dynamics of Local anaesthetics ?
A
- LA in their ionised form bind to sodium channels and prevent sodium entering the nerve cell
- Thus action potential is blocked and no sensory information is sent to the brain
5
Q
Types of nerve fibres ? See pictures
A
- A-Alpha: Myelinated / Motor - Efferent to skeletal muscles
- A-Beta: Myelinated / Touch, pressure & proprioception - Afferent from skin.
- A-Gamma: Myelinated / Motor - Efferent to muscle spindles.
- A-Delta: Pain (sharp + Fast) & temperature - Efferent from skin
- B-type: Myelinated / Preganglionic sympathetic - Efferent to vascular smooth muscles
- C-type: Unmyelinated / Pain (dull + slow) and temperature - Afferent from skin / Postganglionic sympathetic - Efferent to vascular smooth muscle.
6
Q
Order of blockade and recovery of nerve fibres?
A
B fibres > C fibres = A-delta > A-gamma > A-beta > A-Alpha
7
Q
Stages of blockade?
A
- Vasomotor block, dilation of skin vessels and increased cutaneous flow
- Blockade of cold sensation
- Sensation f warmth by patient
- Temperature discrimination lost
- Slow and fast pain lost
- Pessure sense abolished
- Loss of proprioception
- Motor paralysis
8
Q
Anatomy of the vertebrae ?
A
- Consists of pedicle, transverse process, superior/ inferior articular processes and spinous process
- Each vertebrae connected to eachother by intervertebral discs
- There are two superior and inferior articular processes (facet joints)
- Pedicles contain a notch superiorly and inferiorly to allow spinal nerve to root to exit the vertebral column.
9
Q
Spinal cord?
A
- End at L1/L2 in adults
2. Ends at L3 in infants
10
Q
Blood supply of the spinal cord?
A
- Anterior spinal artery (x1)- Formed by vertebral arteries at the base of the skull. Supplies 2/3 of the anterior spinal cord.
- Posterior spinal arteries (x2) - Formed by posterior cerebellar arteries - Travels down the dorsal surface of the spinal cord medial to the dorsal nerve root. Supplies 1/3 of the posterior spinal cord
- Additional blood flow is provided to the anterior and posterior spinal arteries from intercostal and lumbar arteries.
11
Q
Artery of Adamkiewicz?
A
- Radicular artery arising from the aorta. It is large and unilateral on the left side
- Supplies the lower anterior 2/3 of the spinal cord.
- Supplies 68% of perfusion to the lower thorax and upper lumbar areas.
- Injury results in anterior spinal artery syndrome.
12
Q
CSF ?
A
- Fills subarachnoid space
- Total volume 150ml
- About 25-35ml present in the subarachnoid space
- Produced at a rate of 450mls / 24 hours
- Specific gravity is between 1.003 & 1.009
- Produced by the choroid plexus
- Absorbed into the dural venous sinuses via arachnoid villi
13
Q
Boundaries of the Epidural space?
A
- Extends from the foramen magnum to the sacral hiatus
- Anterior boundary: Posterior longitudinal ligament
- Lateral boundries: Pedicles and intervertebral ligaments
- Posteriorly: Ligamentum flavum
14
Q
Brachial plexus? See picture
A
- Contribution from C4-T2
2. Divided into; Roots, trunks, divisions, cords and branches
15
Q
Brachial plexus location?
A
- Brachial plexus and subclavian artery lie on top of the first rib
- Brachial plexus is located lateral and posterior to the subclavian artery
- Subclavian vein and anterior scalene muscle are found medial to the subclavian artery
16
Q
Sciatic nerve ?
A
- Arises from L4/L5 & S1-S3
- Sensory and motor innervation to the LL
- Exits the pelvis via the greater sciatic foramen below the piriformis muscle
- Nerve is deep and anterior to the gluteus maximus and superficial - posterior to the inner muscle layer
- Course down the midline of the posterior thigh and branches into tibial and common peroneal nerves
17
Q
Oburator nerve ?
A
- Originates from L2-L4
- Descends towards the pelvis from the medial border of the psoas major muscle.
- Passes through the obturator foramen. The obturator nerve enters the medial aspect of the thigh
- Divides into anterior branch between adductor longus and brevis muscle and a posterior branch between the adductor brevis and magnus muscles.
- Posterior branch gives off an articular branch to the knee joint.
18
Q
Lateral cutaneous femoral nerve?
A
- Arises from the dorsal divison of L2/L3
- Arises from the lateral border of psoas major muscle - Courses inferiorly and laterally towards the anterior superior illiac spine.
- It passes under the inguinal ligament and over the sartorius muscle into the thigh where it divides into an anterior and posterior branch.
- Provides sensory innervation to the lateral thigh
19
Q
Ilioinguinal / iliohypogastric nerve?
A
- Both arise from L1
- Arise from the upper part of the lateral border fo the psoas major muscle
- Ilioingluinal nerve is small and courses caudad to the iliohypogastric nerve.
- Both nerves cross obliquely anterior to the quadratus lumborum and iliacus muscles and perforate the transversus abdominis near the anterior part of the illiac crest.
- In the anterior abdominal trunk, it travels between the transversus abdominis and the internal oblique.
20
Q
Psoas compartment block?
A
- Lumbar plexus is formed by the anterior division of L1-L4
- The L1 root often receives a branch from T12
- it is located in the posterior 1/3 of the psoas major muscle, anterior to the transverse processes of the lumbar vertebrae.
- The adult lumbar plexus lies deep within the psoas major muscle.
- Not visualised using ultrasound
21
Q
TAP block ?
A
- Anterior abdominal wall innervated by the anterior rami of the lower 6 thoracic nerve (T7-T12) and L1.
- Terminal branches courses between the IOM and TAM
- Provides unilateral analgesia to the skin, muscle and pareital peritonium.
22
Q
Terminal branch - C5
A
Dorsal scapular nerve
23
Q
Terminal branch C5 - C8
A
Longus colli & scelene muscle
24
Q
Terminal branch C5 - C7
A
- Lateral pectoral nerve
- Musculocutaneous nerve
- Long thoracic nerve
25
Q
Terminal branch C5 - C6
A
- Suprascapular
- subclavius
- Axillary nerve
26
Q
Terminal branch C5 - T1
A
- Radial nerve
- Median nerve
27
Q
Terminal branch C7 - T1
A
Ulnar nerve
