APPLIED ANATOMY | Part IV Flashcards
All of the following sacral anatomic landmarks are used to identify the proper location for caudal block EXCEPT:
A. Posterior superior iliac spines (PSISs)
B. Sacral ala
C. Sacral cornu
D. Sacral hiatus
B. Sacral ala
Caudal anesthesia involves the injection of local anesthetics into the caudal epidural
space, the lowest portion of the epidural system accessed through the sacral hiatus.
The sacral hiatus is a defect in the lower part of the posterior wall of the sacrum
formed by the failure of the laminae of S5 and/or S4 to meet and fuse in the midline and is bound by the sacral cornu (palpable on either side of the midline about 1 cm
apart).
The sacral hiatus can be located by drawing/visualizing an equilateral
triangle between the bilateral PSIS and sacral hiatus. Once the sacral hiatus is
identified, a short beveled needle is directed at about 45° to skin and inserted till a
pop is felt, as the sacrococcygeal ligament is pierced.
The needle is then carefully
directed in a cephalad direction at an angle approaching the long axis of the spinal
canal.
When performing a single-shot caudal block, you must first pierce through which ligament?
A. Sacrococcygeal
B. Sacrotuberous
C. Sacrospinous
D. Sacroiliac
A. Sacrococcygeal
Caudal anesthesia involves the injection of local anesthetics into the caudal
epidural space, the lowest portion of the epidural system accessed through the
sacral hiatus. The sacral hiatus is a defect in the lower part of the posterior wall of
the sacrum formed by the failure of the laminae of S5 and/or S4 to meet and fuse in
the midline and is bound by the sacral cornu (palpable on either side of the midline about 1 cm apart).
The sacral hiatus can be located by drawing/visualizing an equilateral triangle between the bilateral PSIS and sacral hiatus. Once the sacral hiatus is identified, a short beveled needle is directed at about 45° to skin and inserted till a pop is felt, as the sacrococcygeal ligament is pierced. The needle is then carefully directed in a cephalad direction at an angle approaching the long axis of the spinal canal.
Piercing this membrane during caudal block produces the “pop” sensation:
A. Sacrococcygeal
B. Sacrotuberous
C. Sacrospinous
D. Sacroiliac
A. Sacrococcygeal
Which of the following pathways carries fibers that control fine touch, vibration, proprioception, and pressure?
A. Dorsal column
B. Spinothalamic
C. Corticospinal
D. Reticulospinal
A. Dorsal column
The dorsal column tract represents an ascending spinal pathway that contains nerve bundles that communicate through a three-neuron system.
First-order neurons have sensory receptor endings and cell bodies in the dorsal root ganglion of the spinal nerve. They synapse with second-order neurons in the dorsal horn, which cross the spinal cord to the opposite side as they ascend to higher levels.
Third-order neurons
are located in the thalamus, which then project to sensory areas in the sensory
cortex. The dorsal column pathway carries fibers that control fine touch, vibration,
proprioception, and pressure.
The spinothalamic tract, an anterolateral system, carries fibers involved in pain
and temperature sensation. It is also an ascending spinal tract that contains nerve bundles that communicate through a three-neuron system.
The corticospinal tract is a
descending pathway that innervates skeletal muscles and muscle stretch receptors.
The reticulospinal tract is a descending pathway that influences voluntary movement and reflexes and is involved in the hypothalamic control of autonomic activity.
- Which of the following pathways carries fibers that are involved in pain and
temperature sensation?
A. Dorsal column
B. Spinothalamic
C. Corticospinal
D. Reticulospinal
B. Spinothalamic
The spinothalamic tract in an ascending spinal pathway carries fibers involved in
pain and temperature sensation. Axons from the periphery travel to the spinal cord
and ascend or descend one to two segments before synapsing at the dorsal root ganglion. Second-order fibers then cross over to the anterolateral portion of the contralateral spinal cord and travel to synapse with third-order neurons in the
thalamus.
From there, third-order neurons carry signals to the cortex.
The dorsal columnar tract represents an ascending spinal tract that carries fibers
that control fine touch, vibration, proprioception, and pressure. The corticospinal tract is a descending pathway, which innervates skeletal muscles and muscle stretch receptors.
The reticulospinal tract is a descending pathway that influences voluntary
movement and reflexes and is involved in the hypothalamic control of autonomic
activity.
What is the potential space between the arachnoid and pia mater?
A. Epidural
B. Subarachnoid
C. Subdural
D. Arachnoid
B. Subarachnoid
The subarachnoid cavity is the interval between the arachnoid and pia mater and
contains the subarachnoid fluid. The arachnoid space refers to the middle meninges.
The spinal dura mater is separated from the arachnoid by a potential cavity, the
subdural cavity. The two membranes are, in fact, in contact with each other, except
where they are separated by a minute quantity of fluid, which serves to moisten the surfaces.
The epidural space describes the space between the wall of the vertebral
canal and the dura and contains a venous plexus and loose areolar tissue.
What is the potential space between the dura and arachnoid mater?
A. Epidural
B. Subarachnoid
C. Subdural
D. Arachnoid
C. Subdural
The spinal dura mater is separated from the arachnoid by a potential cavity, the
subdural cavity. The two membranes are, in fact, in contact with each other, except
where they are separated by a minute quantity of fluid, which serves to moisten the surfaces.
Activation of which opioid receptor types can provide relief from opioid-induced
itching?
A. Mu
B. Delta
C. Sigma
D. Kappa
- Activation of spinal KAPPA receptors is
responsible for the antipruritic effect.
Four major opioid receptor types have been identified: mu (μ), kappa (κ), delta (δ),
and sigma (σ). All opioid receptors couple to G proteins; binding of an agonist to an
opioid receptor causes primarily inhibitory effects that decrease neuronal
excitability.
In the spinal cord, opioids inhibit the release of nociceptive and inflammatory mediators P from dorsal horn sensory neurons attenuating transmission
of painful stimuli (periphery to cortex). In the brainstem, opioids act on descending
inhibitory pathways to attenuate the transmission of painful stimuli.
During neuraxial blockade, the level of sympathetic blockade is generally how
far away from the sensory level?
A. 1-2 dermatomes above
B. 4-6 dermatomes above
C. 1-2 dermatomes below
D. 4-6 dermatomes below
E. 0 dermatome change
The sympathetic level is generally 1-2 dermatome levels higher than the sensory
level. This phenomenon is referred to as differential blockade and is seen in both
neuraxial and peripheral nerve blocks.
In general, sympathetic nerve fibers are
blocked by the lowest concentration of the local anesthetic, followed by sensory
fibers, and then by motor fibers. It is thought that this observation is due in part to nerve fiber diameter and degree of myelination, with smaller diameter and
unmyelinated fibers being more sensitive to the effects of the local anesthetic.
However, this is unlikely to be the sole explanation for the observation of
differential blockade, which is likely a multifactorial phenomenon. Sympathetic
blockade is usually 1-2 dermatomes above the sensory blockade, which is generally
1-3 levels beyond the motor blockade.
During neuraxial blockade, the level of sensory blockade, in general, is how
many dermatomes away from the level of motor blockade?
A. 0
B. 2
C. 4
D. 6
E. 8
B. 2
Cutaneous infiltration of a local anesthetic to block the intercostobrachial
nerve provides anesthesia to which dermatome(s)?
A. C7
B. C8
C. T1
D. T2
T2
The intercostobrachial nerve is a lateral cutaneous branch of the second intercostal
nerve that supplies sensation to the skin of the proximal arm, T2 dermatome.
It is unreliably blocked (often spared) during an axillary brachial plexus approach; to
ensure complete blockade, additional infiltration of local anesthesia can be added
superficially. This superficial block is often performed when tourniquet use is
planned.
Morgan & Mikhail’s Anesthesia
A 37 year old ASA 1 is scheduled for a surgical procedure involving the bladder. At what spinal level does pain conduction of the dome of bladder is:
A. T11 – L2
B. S2 – S4
C. L1 – L2
D. T10
A. T11 – L2
Which of the following findings best indicates complete resolution of spinal anesthesia?
(A) Ability to ambulate
(B) Ability to urinate
(C) Perianal pinprick sensation
(D) Pain at the surgical site
(E) Proprioception of the big toe
(B) Ability to urinate
An analgesic effect similar to the epidural administration of 2.5 mg of morphine could be achieved by which dose of intrathecal morphine?
A. 0.05 mg
B. 0.1 mg
C. 1 mg
D. 2 mg
B. 0.1 mg
The “snap” felt just before entering the epidural space represents passage
through which ligament?
A. Posterior longitudinal ligament
B. Ligamentum flavum
C. Supraspinous ligament
D. Interspinous ligament
B. Ligamentum flavum
which of the following is the correct order of anatomical structures encountered when using paramedian approach for lumbar spinal anesthesia
A) ligamentum flavum, dura, arachnoid matter
B) interspinous ligament, ligamentum flavum, dura, arachnoid matter
C) posterior longitudinal ligament, ligamentum flavum, dura, arachnoid matter
D) anterior longitudinal ligament, ligamentum flavum, dura, arachnoid matter
E) ligamentum flavum, dura, pia matter, arachnoid matter
A) ligamentum flavum, dura, arachnoid matter
Tingling of the 5th finger during spinal anesthesia is associated with anesthesia at
which of the dermatomes?
A) C4
B) C6
C) C8
D) T2
E) T4
C) C8
which of the following neural functions demonstrates highest segmental block after spinal anesthesia?
A) afferent sympathetic activity
B) proprioception
C) sharp pain sensation
D) temperature sensation
E) touch sensation
A) afferent sympathetic activity
In a healthy 24 y.o. women is undergoing knee arthroscopy with spinal anesthesia to level of T4, which of the following findings is LEAST likely:
A) decreased HR
B) decreased hepatic blood flow
C) decreased MAP
D) decreased tidal volume
E) hyperperistalsis
D) decreased tidal volume
Which of the following is the most likely cause of dyspnea during spinal anesthesia with T3 sensory level block?
A) decreased abdominal muscle tone
B) decreased afferent input from the thoracic wall
C) increased dead space ventilation
D) increased intrapulmonary shunting
E) partial diaphragmatic paralysis
B) decreased afferent input from the thoracic wall
A 65 y.o. man undergoes prostatectomy in lithotomy position under spinal anesthesia using bupivacaine 12 mg. Ten hours later, he reports his left foot is numb.
Exam shows decreased pin prick sensation over the lateral dorsal aspect of the left foot. Dorsiflexion is limited. Which of the following is most likely?
A) cauda equina syndrome
B) compression of common peroneal nerve
C) compression of post tibial nerve
D) L5 nerve root damage
E) stretching of sciatic nerve
B) compression of common peroneal nerve
Common elements present in cauda equina syndrome after continuous spinal anesthesia
A) use of micro catheter
B) maldistribution of local anesthetic problems
C) administration of lidocaine
D) addition of epinephrine
B) maldistribution of local anesthetic problems
The deep peroneal nerve innervates the:
A. Lateral aspect of the dorsum of the foot
B. Entire dorsum of the foot
C. Web space between the great toe and the second toe
D. Medial aspect of the dorsum of the foot
C. Web space between the great toe and the second toe
The correct arrangement of local anesthetics in order of their ability to
produce cardiotoxicity from most to least is:
A. Bupivacaine, lidocaine, ropivacaine
B. Bupivacaine, ropivacaine, lidocaine
C. Ropivacaine, bupivacaine, lidocaine
D. Lidocaine, ropivacaine, bupivacaine
B. Bupivacaine, ropivacaine, lidocaine
Severe hypotension associated with high spinal anesthesia is caused primarily
by:
A. Decreased cardiac output secondary to decreased preload
B. Decreased systemic vascular resistance
C. Decreased cardiac output secondary to bradycardia
D. Decreased cardiac output secondary to decreased myocardial
contractility
A. Decreased cardiac output secondary to decreased preload
Select the FALSE statement regarding spinal anatomy and spinal anesthesia:
A. The addition of phenylephrine to lidocaine will prolong spinal anesthesia
B. A high thoracic sensory block will result in total sympathetic blockade
C. The largest vertebral interspace is L5-S1
D. The dural sac extends to the S4-S5 interspace
D. The dural sac extends to the S4-S5 interspace - FALSE
dural sac extends to S2!
The MAIN advantage of neurolytic nerve blockade with phenol versus alcohol is:
A. Denser blockade
B. Blockade is permanent
C. The effects of the block can be evaluated immediately
D. The block is less painful
D. The block is less painful
A 75-year-old man is scheduled to undergo elective orchiectomy for prostate
cancer. The patient has selected spinal anesthesia. What is the minimum
dermatomal level that must be achieved to carry out this operation?
A. T4
B. T10
C. L3
D. S1
B. T10
The artery of Adamkiewicz MOST frequently arises from the aorta at which
spinal level?
A. T1-T4
B. T5-T8
C. T9-T12
D. L1-L4
C. T9-T12
A retrobulbar block anesthetizes each of the following nerves EXCEPT
A. Ciliary nerves
B. Cranial nerve III (oculomotor nerve)
C. Cranial nerve VII (facial nerve)
D. Cranial nerve VI (abducens nerve)
C. Cranial nerve VII (facial nerve)
The stellate ganglion lies in closest proximity to which of the following
vascular structures?
A. Common carotid artery
B. Internal carotid artery
C. Vertebral artery
D. Aorta
C. Vertebral artery
Which of the following structures in the antecubital fossa is the MOST
medial?
A. Brachial artery
B. Radial nerve
C. Tendon of the biceps
D. Median nerve
D. Median nerve
Cutaneous innervation of the plantar surface of the foot is provided by:
A. Sural nerve
B. Posterior tibial nerve
C. Saphenous nerve
D. Deep peroneal nerve
B. Posterior tibial nerve
Which of the following is NOT a branch of the SCIATIC NERVE?
A. Posterior tibial nerve
B. deep peroneal nerve
C. Saphenous nerve
D. superficial peroneal nerve
C. Saphenous nerve
A 32-year-old army officer is unable to oppose the left thumb and left little
finger after an 8-hour exploratory laparotomy under general anesthesia. He
had an IV induction through a peripheral IV and had a second IV placed in
the antecubital fossa after he was asleep.
Damage to which of the following
nerves would MOST likely account for this deficit?
A. Radial
B. Ulnar
C. Median
D. Musculocutaneous
C. Median
Antecubital fossa - most frequently injured nerve is MEDIAN NERVE.
Which portion of the upper extremity is NOT innervated by the brachial
plexus?
A. Posterior medial portion of the arm
B. Elbow
C. Lateral portion of the forearm
D. Medial portion of the forearm
A. Posterior medial portion of the arm - Supplied by intercostobrachial nerve
A celiac plexus block would NOT effectively treat pain resulting from a
malignancy involving which of the following organs?
A. Uterus
B. Stomach
C. Pancreas
D. Gallbladder
A. Uterus
Pelvic organs - supplied by HYPOGASTRIC PLEXUS
Which nerves must be adequately blocked in order to perform the surgery requiring ANKLE BLOCK?
A. Deep peroneal, posterior tibial, saphenous, sural
B. Deep peroneal, saphenous, superficial peroneal, sural
C. Deep peroneal, posterior tibial, superficial peroneal, sural
D. Deep peroneal, superficial peroneal, posterior tibial, saphenous
D. Deep peroneal, superficial peroneal, posterior tibial, saphenous
Epidural use of which of the following opioids would result in the
GREATEST incidence of delayed respiratory depression?
A. Sufentanil
B. Fentanyl
C. Morphine sulfate
D. Hydromorphone
C. Morphine sulfate
A 21-year-old patient reports tingling in her thumb during her cesarean section under epidural anesthesia. To which dermatomal level would this correspond?
A. C5
B. C6
C. C7
D. C8
B. C6
The most common complication of a celiac plexus block is
A. Hypotension
B. Seizure
C. Retroperitoneal hematoma
D. Constipation
A. Hypotension
Through which of the following would a spinal needle NOT pass during a
midline placement of a subarachnoid block in the L3-L4 lumbar space?
A. Supraspinous ligament
B. Interspinous ligament
C. Posterior longitudinal ligament
D. Dura mater
C. Posterior longitudinal ligament
Inhibitory presynaptic fibers to the gastrointestinal tract:
A. C3-C5
B. T1-T4
C. T5-T12
D. T10-L1
E. S2-S4
C. T5-T12
