Anatomy Flashcards
A patient is undergoing a brachiobasilic AV fistula placement. He states that he feels pain at the surgical site of his medial upper arm despite a successful supraclavicular block. Which nerve block could have prevented this pain?
Intercostobrachial nerve block
The intercostobrachial nerve is usually missed when performing a brachial plexus block (usually arises from the dorsal rami of T2 and thus is spared by all brachial plexus blocks)
Subcutaneous infiltration of the entire width of the axillary crease will block which nerve?
Intercostobrachial nerve
Which nerve is usually missed when performing a brachial plexus block?
The intercostobrachial nerve is usually missed when performing a brachial plexus block (usually arises from the 2nd thoracic nerve root T2)
Brachial Plexus
Interscalene blocks target what level of the brachial plexus?
Roots & Trunk
Supraclavicular blocks target what level of the brachial plexus?
Trunk & Divisions
Infraclavicular blocks target what level of the brachial plexus?
Cords
Axillary blocks target what level of the brachial plexus?
Branches
Supraclavicular blocks are ideal for what kind of surgery?
Supraclavicular blocks are ideal for elbow surgery.
Infraclavicular blocks cover what part of the upper extremity?
Infraclavicular blocks cover the upper arm and elbow.
Axillary blocks are ideal for what kind of surgery?
Wrist and hand
The femoral nerve arises from what lumbar nerves?
L2-L4
The sciatic nerve arises from what lumbar nerves?
L4-L5
S1-S3
NOTE:
Sciatic nerve divides into the tibial nerve and common peroneal nerve (fibular).
The saphenous nerve is a branch of what nerve?
The saphenous nerve is a branch of the femoral nerve.
The saphenous nerve is covered in what block?
Adductor canal block
Adductor Canal Block
The sciatic nerve branches into the tibial and common peroneal nerve which control what motor movements?
Tibial- inversion, plantar flexion
Peroneal- eversion, dorsiflexion
TIP, PED
The common peroneal nerve gives off what two branches?
Superficial Peroneal: innervates dorsal side of foot
Deep Peroneal: innervates webspace between 1st and 2nd toe
_ is a branch of the tibial nerve which provides sensation to the lateral aspect of the foot.
The sural nerve is a branch of the tibial nerve which provides sensation to the lateral aspect of the foot.
What are the five nerves targeted in an ankle block?
Saphenous nerve
Posterior tibial nerve
Sural nerve
Superficial peroneal nerve
Deep peroneal nerve
NOTE:
“5 notes = 5 nerves”
Sensation of thigh from lateral to medial.
Lateral femoral cutaneous
Femoral nerve
Obturator nerve
Sensation of lower leg/foot from medial to lateral.
Saphenous nerve
Peroneal nerve (common, superficial, deep)
Sural nerve
In adults, the spinal cord ends at what level?
L1-L2
In infants, the spinal cord ends at what level?
L3
What is the purpose of an epidural test dose?
To ensure catheter isn’t intravascular or intrathecal.
Lidocaine 1.5% + 1:200,000 epinephrine, 3cc
Positive Intravascular:
Epinephrine: HR increases within 60 seconds (>10bpm); BP increases (> 20 mmHg)
(Beta-blockers, opioids, other sedatives can blunt this response)
Lidocaine: “LA toxicity” symptoms like tinnitus, perioral numbness, metallic taste, dizziness
Positive Intrathecal: Sensory loss within 1-2 min, motor loss within 3-4 minutes (different from epidural administration of local anesthetics); hypotension; dizziness; general feeling of malaise (until you treat the hypotension)
Risk factors for Post-Dural Puncture Headache (PDPH)?
Younger (patient age 18-50 highest risk)
Female sex
Pregnancy
Low body mass index
Use of cutting (beveled) spinal needles (as opposed to pencil point)
Use of larger needles (22G / Touhy)
Prior history of headaches (questionable ??)
Definitive treatment for PDPH?
Blood patch
Pencil-point spinal needles include…
Whitacre & Sprotte
NOTE:
Reduces risk of PDPH
Cutting tip spinal needles include…
Quincke
“Quincke will Cut you”
Contraindications to neuraxial anesthesia include:
Patient refusal or inability to stay still / tolerate procedure
Infection at site of injection
Coagulopathy: generally want INR < 1.5 and platelets > 70K
Increased ICP (creating a hole in the dura (deliberately or accidentallymay result in brainstem herniation if sufficient volume of CSF leaks out of the intrathecal space)
Refractory hypovolemia (all neuraxial blocks drop BP to some degree)
Sepsis
True allergy to local anesthetic
Recommendations to hold and continue anticoagulation for epidurals
Name the nerve in this axillary nerve block.
Musculocutaneous nerve
Anatomy of the popliteal fossa
NOTE:
The tibial nerve is lateral and superficial to the popliteal artery/vein.
In an adductor canal block, what muscles form the roof, lateral border, and medial border?
Roof- Sartorius
Medial- Adductor magnus, adductor longus
Lateral- Vastus medialis
When performing an US guided sciatic nerve block in the popliteal fossa, the most anterior structure on the ultrasound in the popliteal fossa is what?
Popliteal artery
Factors that affect local anesthetic spread for epidurals?
Factors that affect local anesthetic spread for spinals?
What factor can aid in prolonging neuraxial blockade (epidurals, spinals)?
Epinephrine- duration
Lipid solubility- potency
pka/bicarb- onset
The _ muscle adducts the vocal cords.
The _ muscle abducts the vocal cords.
The posterior cricoarytenoid muscle abducts the vocal cords.
The lateral cricoarytenoid muscle adducts the vocal cords
Both muscles are innervated by the RLN.
Unilateral RLN injury
Bilateral RNL injury
Unilateral RLN injury
= hoarseness, weak voice
Bilateral RNL injury
= aphonia, airway obstruction
Review Dermatomes
Paravertebral block
For the parasagittal US guided technique, the transverse process, costotransverse ligament (CTL), and the pleura are identified with the probe parralel to the spinous process. The needle is directed towards the CTL and then through the CTL which may result in a tactile change in resistance. LA is then injected into the paravertebral space.
The transverse process serves as a key landmark. The needle is inserted until it contacts the transverse process. Once it is encountered, the needle is withdraw and angled to “walk off” the transverse process until the CTL is found.
When performing a lumbar paramedian approach for spinal anesthesia what structures are encountered from first to last?
Ligamentum flavum
Epidural space
Dura mater
Arachnoid mater
NOTE:
Supraspinous and interspinous ligament are avoided.
Which nerve fibers carry pain signals?
Type A- delta (fastest)
Type C
Type A- delta are more myelinated and are thicker than Type C fibers, hence they have the fastest transmission of nociception.
Anatomy of the larynx
Correct neck anatomical landmarks for a superficial cervical plexus block?
Posterior boder of the SCM
Halfway between its insertion on the clavicle and mastoid process.
Superficial cervicle plexus block
Complications of a superificial cervicle plexus block?
Vertebral artery injection (seizures)
Epidural/intrathecal spread
Hemidiaphragmatic paralysis
Gag reflex
Afferent limb:
Efferent limb:
Gag reflex
Afferent limb: Glossopharyngeal (IX)
Efferent limb: Vagus (X)
Factors that affect duration of neuraxial anesthesia?
Redistribution/vascular absoprtion (#1)
CSF volume
Lipophilicity
The artery of adamkiewicz most commonly originates at what spinal level?
T9-T12
If a patient seizes after injection of LA during an interscalene block what artery was accidently injected?
Vertebral artery
The most important site of action for spinal and epidural anesthesia are:
The most important site of action for spinal and epidural anesthesia are the doral root ganglia and spinal nerve roots.
Supraclavicular nerve block
Corneal Reflex
Afferent:
Efferent:
Corneal Reflex
Afferent: V1
Efferent: VII
Thoracic epidurals have what GI effects?
Increased peristalsis
When performing a femoral nerve block which fascial layer is encountered first?
Fascia lata
Nociceptors (primary afferent neurons) consist of what two fiber types?
A-delta fibers
C fibers
What landmark is used for a stellate ganglion block?
Chassaignac Tubercle (C6)
