Estimated reading time: 5 minutes
If you’re preparing for the regional anesthesia exam, most of you tend to ask what the best resources are. Dr Jhanvi Bajaj advises that the reference book of choice is Shemby’s Regional Anesthesia. It has both MCQs and theoretical answers to questions across nearly all subjects. The other useful resource is the Ganga Hospital Handbook of Regional Anesthesia, and you can generally obtain this as a PDF from past fellows. In combination, these are good to use to prepare for the exam.
Let’s go through some high-yield MCQs discussed in detail:
MCQ 1: Sudden Drop in Blood Pressure After Spinal Anesthesia
Scenario:
A 48-year-old man with well-controlled type 2 diabetes is scheduled for a total hip replacement. He receives 12 mg of hyperbaric bupivacaine. Seven minutes later, his blood pressure drops from 140/85 to 90/60 mmHg. He is alert, comfortable, and has no chest pain, palpitations, or shortness of breath.
Question: What is the most likely explanation for this acute hypotension?
Option Analysis:
- Acute myocardial ischemia: Typically presents with chest pain, palpitations, sweating, arrhythmias, or restlessness. None of these are noted, so it is unlikely.
- Systemic toxicity of local anesthetic (LAST): Features include peri-oral paresthesia, numbness, headache, tinnitus, metallic taste, seizures, or arrhythmias. None of these is described.
- Accidental intravascular injection: 2.5 mL of hyperbaric bupivacaine is insufficient to be toxic.
- Normal sequence of spinal anesthesia ✅
Why:
Spinal anesthesia suppresses nerve fibres in the sequence: autonomic → sensory → motor. Thoracolumbar spinal nerves’ sympathetic fibres are blocked initially. This results in vasodilation and leads to a precipitous fall in blood pressure.
Management:
- Give IV fluids to restore intravascular volume.
- If required, administer vasoconstrictors such as phenylephrine, ephedrine, or mephentermine.
MCQ 2: Caudal Block in a Child
Scenario:
A 4-year-old boy is to undergo circumcision using general anesthesia. For pain relief postoperatively, a caudal block is done. One feels a definite “pop” or give-way as the needle traverses the sacral hiatus.
Question: What ligament causes this sensation?
Discussion:
- Caudal anesthesia is essentially an epidural block, but is done via the sacral hiatus.
- Usually reserved for children younger than 8, since the sacral cornu ossifies and closes the hiatus after this age.
Landmarks for Caudal Block:
- Palpate the posterior superior iliac spines (PSIS).
- Concept an equilateral triangle below the PSIS – the sacral hiatus is the central depression.
- The sacral cornua are palpable on either side.
Needle Pathway:
- Skin
- Subcutaneous tissue
- Sacrococcygeal ligament ✅ – this is the “pop” felt.
After piercing the ligament, the needle enters the caudal space, and local anesthetic is administered.
Tip: The sensation of “pop” is the feeling of crossing the sacrococcygeal ligament and entering the caudal epidural space.
MCQ 3: Femoral Nerve Block Anatomy
Scenario:
A 62-year-old woman with advanced knee osteoarthritis undergoes elective total knee arthroplasty. Post-op analgesia will be achieved with a USG-guided femoral nerve block by the anesthetist.
Question: Where is the femoral nerve in relation to the femoral artery?
Discussion:
Femoral nerve blocks are less frequent for TKA since they cause weakening of the quadriceps, complicating early mobilization. Adductor canal block or local infiltration is used by surgeons for analgesia while maintaining the patient mobile.
Anatomy:
- Two fasciae enclose the nerve: fascia lata superiorly and fascia iliaca, which come into contact with the nerve.
- The femoral nerve is lateral and posterior to the femoral artery.
- Remember VAN: Vein → Artery → Nerve, medial to lateral.
- The Sartorius muscle courses from lateral to medial, assisting in localising the nerve.
Technique: Use an in-plane approach, following the nerve from the knee to the inguinal crease before branching.
✅ Answer: Lateral to the femoral artery
MCQ 4: Pudendal Nerve Block
Scenario:
A 38-year-old man with perineal and genital pain (pudendal neuralgia) needs a USG-guided pudendal nerve block.
Question: If the drug diffuses too laterally past the internal pudendal artery, what nerve might be blocked as well?
Discussion:
- The pudendal nerve arises from S2–S4 and supplies the perineum, external genitalia, and anal region.
- It passes from the greater sciatic foramen, between sacrospinous and sacrotuberous ligaments, and re-enters the pelvis via the lesser sciatic foramen, lying near the internal pudendal artery and vein.
- Lateral spread of the drug beyond the artery may block the sciatic nerve.
✅ Answer: Sciatic nerve
MCQ 5: Nerve Blocks for Complete Foot Anesthesia
Scenario:
A 45-year-old man with chronic gout is undergoing surgery on the foot. The anesthetist desires a USG-guided ankle block for the whole foot.
Question: What nerves require blocking for complete anesthesia?
Discussion:
Dorsal surface:
- Superficial peroneal nerve – the greater part of the dorsal foot
- Deep peroneal nerve – first web space
- Sural nerve – lateral half
Plantar surface:
- Saphenous nerve – medial foot
- Tibial nerve (TBL) → medial & lateral plantar branches
- Sural nerve – lateral foot
✅ Answer: Superficial peroneal, deep peroneal, tibial (medial & lateral plantar), saphenous, and sural nerves
Conclusion:
Dr. Jhanvi Bajaj’s discussion emphasises how anatomy, nerve physiology, and clinical reasoning must be mastered in order to excel on regional anesthesia exams. These MCQs are just a small subset of what you must learn for success with both exams and patient care.
For access to more high-yield questions, detailed explanations, and focused preparation for SS, NEET, and fellowship exams, subscribe to Conceptual Anesthesia. You’ll get carefully curated MCQs, step-by-step discussions, and expert guidance to boost your preparation.
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Click Here to Watch:
- Regional Anesthesia PYQs | SS MCQ Discussion Part-1 by Dr. Jhanvi Bajaj
- Crack Regional Anesthesia SS MCQ’s Discussion Part-2 by Dr. Jhanvi Bajaj
