BJA MCQ Flashcards
Question 1
Appropriate statements regarding performance of an epidural include:
Select only the statements that you believe to be true. Leave the box blank if you believe the answer to be false.
The interspinous ligament but not the supraspinous ligament is traversed during the paramedian approach.
The Tuohy needle first enters the anterior epidural space.
Taylor’s approach involves inserting the epidural needle at the L5–S1 interspace.
The optimal catheter length in the epidural space is 4–5 cm.
A subdural block is likely to be misinterpreted as migration of the tip of the catheter.
(a) False. If a paramedian approach is used, then the supraspinous and interspinous ligaments are not engaged.
(b) False. The Tuohy needle enters the posterior epidural space.
(c) True. This approach is an alternate paramedian approach at the L5–S1 interspace, for patients with challenging anatomy, where a midline approach may be impossible.
(d) True. The risk of complications, including curling, knotting and unilateral or inadequate block, increases beyond 7 cm.
(e) True. Subdural blocks may present in a variety of ways, classically with a unilateral sensory block with variable motor and disproportionate sympatholysis.
Question 2
Appropriate statements regarding the anatomy of the epidural space include:
Select only the statements that you believe to be true. Leave the box blank if you believe the answer to be false.
Venous drainage is via the basilar venous plexus.
The cauda equina resides within the epidural space.Compared with the thoracic epidural space, the lumbar epidural space is deeper and wider.
The anterior border of the epidural space is the posterior longitudinal ligament.
The sacrococcygeal membrane forms the inferior boundary.
(a) False. Via the valveless Batson plexus.
(b) False. The cauda equina is a bundle of nerve roots that sit within the subarachnoid space distal to the conus medullaris.
(c) True. There is a progressive increase in depth and width of the epidural space (i.e. it is 1–1.5 mm at C5, 2.5–3 mm at T6 and 5–6 mm at L2. This increase may explain why high thoracic epidurals tend to spread more causally.
(d) True. The superior boundary is at the foramen magnum, the anterior boundary is the posterior longitudinal ligament, the lateral boundary are the pedicles and intervertebral foraminae and the posterior boundary is the ligamentum flavum.
(e) True. The sacrococcygeal membrane forms the inferior boundary. See previous answer for other boundaries.
Question 3
Appropriate statements regarding the anatomy of the vertebral column include:
Select only the statements that you believe to be true. Leave the box blank if you believe the answer to be false.
There are 32 paired spinal nerves.
There are seven cervical spinal nerves, each corresponding to the vertebra above which it emerges.
During its development, the ligamentum flavum begins as right and left halves, which then fuse in the
There is a reduction in epidural adipose tissue in the elderly.
The thoracic, lumbar and sacral spinal nerves are numbered by the vertebra above.
(a) False. There are 31 paired spinal nerves.
(b) False. There are eight cervical spinal nerve pairs (C1–8). The cervical nerves are numbered by the vertebra below (except C8, which emerges below C7 and above T1).
(c) True. At certain levels of the spine, this midline fusion can be absent. This absence can risk failure to identify loss of resistance in the midline/interlaminar approach to epidural anaesthesia.
(d) True. Individual variability of fat within the epidural space may account for varying spread and intensity of local anaesthetic effect.
(e) True. This nomenclature contrasts with that of most of the cervical spinal nerves. With the exception of C8 that emerges above T1 and below C7 vertebra, cervical spinal nerves are numbered by the vertebra below.
Question 4
Appropriate statements regarding the anatomy and physiology of epidurals include:
Select only the statements that you believe to be true. Leave the box blank if you believe the answer to be false.
During the paramedian approach, the ligamentum flavum is not engaged.Depth to epidural space has been shown to be directly proportional to the patient’s height.The ligamentum flavum is insensate.
Using ultrasound, the interlaminar and transverse process views provide an image of neuraxial structures through acoustic windows.Within the spinal canal, the venous plexus of Batson is predominantly anterior.
(a)False. In the paramedian approach, needle entry is slightly caudal and lateral to the inferior aspect of the spinous process. The needle is walked off the lamina into paraspinous tissue until the ligamentum flavum is engaged.
(b)False. Epidural space depth has been shown to vary with weight, BMI and ethnicity. It does not vary with height, age or gestation.
(c)True. The ligamentum flavum is insensate. The posterior dura is also sparsely innervated compared with the anterior dura.
(d)False. The interlaminar and interspinous views provide an image of the neuraxial structures through acoustic windows.
(e)True. This statement is fortunate, as it reduces risk of venous puncture or catheterization.
