CRNA Regional Anesthesia and Nerve Blocks 2 — Questions and Answers
Question 1: The interscalene brachial plexus block is the preferred regional technique for surgery on which anatomical region?
- Hand and wrist
- Elbow and proximal forearm
- Shoulder and proximal humerus (Correct answer)
- Lower arm and digits
Correct answer: Shoulder and proximal humerus
The interscalene block targets the C5-C7 roots of the brachial plexus, providing excellent anesthesia for shoulder and proximal humerus surgery where these roots are dominant.
Question 2: Which complication occurs in nearly 100% of interscalene brachial plexus blocks?
- Pneumothorax
- Ipsilateral phrenic nerve palsy (Correct answer)
- Ipsilateral Horner syndrome
- Recurrent laryngeal nerve block
Correct answer: Ipsilateral phrenic nerve palsy
The phrenic nerve (C3-C5) runs directly adjacent to the brachial plexus at the interscalene level and is invariably blocked, causing ipsilateral hemidiaphragm paresis—a critical consideration in patients with contralateral phrenic nerve palsy or severe pulmonary disease.
Question 3: The femoral nerve block provides sensory coverage primarily to which area?
- Posterior thigh and popliteal fossa
- Anterior and medial thigh, knee, and medial leg (Correct answer)
- Lateral thigh and lateral leg only
- Entire lower extremity including the foot
Correct answer: Anterior and medial thigh, knee, and medial leg
The femoral nerve (L2-L4) innervates the anterior and medial thigh, the knee joint, and the medial aspect of the leg and foot via the saphenous nerve, making it highly useful for knee surgery analgesia.
Question 4: During an axillary brachial plexus block, which nerve most commonly requires a separate injection because it exits the neurovascular sheath proximal to the standard injection site?
- Ulnar nerve
- Radial nerve
- Musculocutaneous nerve (Correct answer)
- Median nerve
Correct answer: Musculocutaneous nerve
The musculocutaneous nerve typically exits the brachial plexus sheath high in the axilla and enters the coracobrachialis muscle before the standard axillary injection site, requiring a separate injection into that muscle for complete block.
Question 5: Which combination of nerve blocks provides comprehensive analgesia for an above-knee amputation?
- Femoral nerve block alone
- Sciatic nerve block alone
- Femoral and lateral femoral cutaneous nerve blocks
- Femoral and sciatic nerve blocks (Correct answer)
Correct answer: Femoral and sciatic nerve blocks
Above-knee amputation requires coverage of both the anterior thigh (femoral nerve) and the posterior thigh through the sciatic nerve distribution, necessitating a combined femoral and sciatic nerve block.
Question 6: The transversus abdominis plane (TAP) block primarily targets which type of pain following abdominal surgery?
- Deep visceral pain
- Somatic pain from the anterior abdominal wall (Correct answer)
- Diaphragmatic referred shoulder pain
- Retroperitoneal organ pain
Correct answer: Somatic pain from the anterior abdominal wall
The TAP block deposits local anesthetic between the internal oblique and transversus abdominis muscles, blocking thoracolumbar nerves (T10-L1) that supply the anterior abdominal wall, providing somatic incisional analgesia.
Question 7: Which local anesthetic is preferred for continuous peripheral nerve block infusions due to its long duration, favorable sensory-motor differential, and lower cardiotoxicity?
- Lidocaine
- Mepivacaine
- Ropivacaine (Correct answer)
- Tetracaine
Correct answer: Ropivacaine
Ropivacaine is the S-enantiomer with long duration of action, produces preferential sensory block over motor block at lower concentrations, and has lower cardiac and CNS toxicity compared to racemic bupivacaine.
CRNA Regional Anesthesia and Nerve Blocks 2
The interscalene brachial plexus block is the preferred regional technique for surgery on which anatomical region?