Regional Anesthesia Practice Questions

Q: Identify the needle shown in the image:

Tuohy epidural needle. ***Tuohy epidural needle*** - This needle features a **distal curved tip (Huber point)** which helps to deflect the **epidural catheter** cranially or caudally upon insertion. - It is specifically designed for the **loss of resistance** technique to identify the **epidural space**. *Quincke spinal needle* - Characterized by a **cutting tip** designed to pierce the dura mater during **spinal anesthesia**. - The **sharp bevel** helps to minimize force required for insertion but increases the risk of **post-dural puncture headache (PDPH)**. *Huber needle* - Originally designed with a **90-degree bend** and an **anti-coring point** for accessing **implanted ports**. - It is used specifically to prevent coring of the **silicone septum** of central venous access devices. *Veress needle* - A spring-loaded, blunt-tipped needle used during **laparoscopic surgery** to establish a **pneumoperitoneum**. - It includes a **safety mechanism** with an inner stylet that retracts when it encounters resistance and clicks forward upon entering the **peritoneal cavity**.

Q: During a lumbar puncture procedure, the spinal needle traverses several anatomical layers in a defined sequence before reaching the subarachnoid space. Given the structures listed below, which option correctly represents the order in which they are pierced? 1. Ligamentum flavum 2. Supraspinous ligament 3. Interspinous ligament 4. Dura mater 5. Subdural space 6. Arachnoid mater 7. Epidural space Which option correctly represents the order in which they are pierced?

2 → 3 → 1 → 7 → 4 → 5 → 6. ***2 → 3 → 1 → 7 → 4 → 5 → 6*** - The needle first penetrates the **supraspinous ligament**, followed by the **interspinous ligament**, and then the **ligamentum flavum** (the 'yellow ligament'), which provides a distinct 'pop' sensation upon entry. - After passing through the ligamentum flavum, the needle enters the **epidural space**, then pierces the **dura mater**, traverses the **subdural space**, and finally enters the **subarachnoid space** (after passing the arachnoid mater).*2 → 3 → 7 → 1 → 4 → 5 → 6* - This sequence incorrectly places the **epidural space** (7) before the **ligamentum flavum** (1). - The ligamentum flavum must be pierced to gain access from the superficial tissues into the epidural space, not vice versa.*3 → 2 → 1 → 7 → 4 → 5 → 6* - This sequence starts with the **interspinous ligament** (3), erroneously placing it before the **supraspinous ligament** (2). - The supraspinous ligament is the most superficial structure among the spinal ligaments involved in a midline lumbar puncture, thus it must be pierced first.*2 → 1 → 3 → 4 → 7 → 5 → 6* - This sequence incorrectly places the **ligamentum flavum** (1) before the **interspinous ligament** (3) and implies the dura is pierced before the epidural space. - Anatomically, the needle must pass through the interspinous ligament before reaching the deeper ligamentum flavum, and the epidural space lies between the ligamentum flavum and the dura.

Q: During ultrasound-guided supraclavicular block, you observe the brachial plexus as a 'bunch of grapes' appearance. The subclavian artery appears pulsatile underneath. You notice a hyperechoic line moving with respiration above the artery. What does this structure represent and what is its clinical significance?

Pleura - indicates risk of pneumothorax. ***Pleura - indicates risk of pneumothorax*** - The **pleura** appears as a **hyperechoic**, shimmering line that exhibits **respiratory sliding**, located deep and lateral to the **subclavian artery**. - Identifying this structure is critical to avoid accidental needle puncture, which can lead to a **pneumothorax**, a classic complication of the supraclavicular approach. *First rib - landmark for needle placement* - The **first rib** is also **hyperechoic** but presents as a static, shadowing structure that does not move with respiration. - It serves as a safety barrier; keeping the needle tip above the **first rib** prevents it from entering the underlying lung tissue. *Prevertebral fascia - anatomical landmark* - The **prevertebral fascia** envelops the **brachial plexus** trunks but does not demonstrate the characteristic **sliding motion** seen with the pleura during breathing. - While it is a key landmark for identifying the **plexus sheath**, it does not correlate with the dynamic respiratory movement described in the prompt. *Subclavian vein - vascular complication risk* - The **subclavian vein** is typically located medial to the **subclavian artery** and appears as an **anechoic** (black), compressible oval. - It is not a hyperechoic line and does not possess the distinct **shimmering** appearance associated with the visceral and parietal pleural interface.

Q: A patient is scheduled for femoral nerve block. On ultrasound, you identify a pulsatile structure lateral to the femoral vein. How should you proceed?

Inject local anesthetic lateral to this structure. ***Inject local anesthetic lateral to this structure*** - The pulsatile structure lateral to the femoral vein is the **femoral artery**; based on the **NAVEL** mnemonic (Nerve, Artery, Vein, Empty space, Lymphatics) from lateral to medial, the nerve is located most laterally. - For a successful femoral nerve block, local anesthetic must be deposited **lateral to the artery**, specifically deep to the **fascia iliaca** to surround the hyperechoic nerve bundle. *Inject local anesthetic medial to this structure* - Injecting medial to the femoral artery results in deposition near the **femoral vein** or the **femoral canal**, which contains lymphatics but no major nerves. - This approach carries a high risk of **accidental intravascular injection** into the femoral vein and will not achieve a nerve block. *This is the femoral artery; inject between artery and vein* - The space between the femoral artery and vein contains connective tissue but does not house the **femoral nerve**. - Injecting in this plane increases the risk of **vascular injury** and systemic toxicity without providing any clinical analgesia for the femoral territory. *This represents the nerve; inject at this location* - A **pulsatile structure** on ultrasound is characteristic of an artery (the femoral artery), whereas the femoral nerve appears as a non-pulsatile, **hyperechoic**, triangular or oval structure. - Injecting directly into a pulsatile structure would result in an **intra-arterial injection**, potentially leading to **Local Anesthetic Systemic Toxicity (LAST)** or distal ischemia.

Question 1

Identify the needle shown in the image:

Accepted Answer

Tuohy epidural needle

Answer

Quincke spinal needle

Answer

Huber needle

Answer

Veress needle

Question 2

During a lumbar puncture procedure, the spinal needle traverses several anatomical layers in a
defined sequence before reaching the subarachnoid space. Given the structures listed below,
which option correctly represents the order in which they are pierced?
1. Ligamentum flavum
2. Supraspinous ligament
3. Interspinous ligament
4. Dura mater
5. Subdural space
6. Arachnoid mater
7. Epidural space
Which option correctly represents the order in which they are pierced?

Accepted Answer

2 → 3 → 1 → 7 → 4 → 5 → 6

Answer

2 → 3 → 7 → 1 → 4 → 5 → 6

Answer

3 → 2 → 1 → 7 → 4 → 5 → 6

Answer

2 → 1 → 3 → 4 → 7 → 5 → 6

Question 3

A 28-year-old ASA I patient undergoes ultrasound-guided axillary block. Despite clear visualization of local anesthetic spread around all three major nerves, the patient develops incomplete block in the distribution of musculocutaneous nerve. What is the most likely anatomical explanation?

Accepted Answer

The musculocutaneous nerve has already entered the coracobrachialis muscle at the level of injection

Answer

The nerve has anatomical variation with dual innervation

Answer

Inadequate volume of local anesthetic was used

Answer

The needle was placed too proximal in the axilla

Question 4

During ultrasound-guided supraclavicular block, you observe the brachial plexus as a 'bunch of grapes' appearance. The subclavian artery appears pulsatile underneath. You notice a hyperechoic line moving with respiration above the artery. What does this structure represent and what is its clinical significance?

Accepted Answer

Pleura - indicates risk of pneumothorax

Answer

First rib - landmark for needle placement

Answer

Prevertebral fascia - anatomical landmark

Answer

Subclavian vein - vascular complication risk

Question 5

A patient is scheduled for femoral nerve block. On ultrasound, you identify a pulsatile structure lateral to the femoral vein. How should you proceed?

Accepted Answer

Inject local anesthetic lateral to this structure

Answer

Inject local anesthetic medial to this structure

Answer

This is the femoral artery; inject between artery and vein

Answer

This represents the nerve; inject at this location

Regional Anesthesia — MCQs

Regional Anesthesia — MCQs

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