The anterior
longitudinal ligament is a vertical connective tissue band that
attaches along the anterior aspects of the vertebral bodies. Its
peripheral fi bers have strong attachments to the intervertebral
discs. The anterior longitudinal ligament resists hyperextension
of the vertebral column. However, in this patient, the
extreme forces involved with the hyperextension of the neck
overpowers the resistance of this ligament, rupturing it as well
as displacing part of the C4-5 intervertebral disc. In the given
T2-weighted MRI, the anterior longitudinal ligament is represented
by a hypointense (dark band) signal located anterior to
the vertebral column. However, the locations where the anterior
longitudinal ligament is interrupted appear as an abnormal
hyperintense (white) signal, which is evident anterior to the C5 vertebral body. Choice B (Posterior longitudinal ligament)
is incorrect. The posterior longitudinal ligament runs vertically
along the posterior aspect of the vertebral column,
mirroring the position of the anterior longitudinal ligament
located along the anterior aspect of the vertebral column. The
posterior longitudinal ligament resists fl exion of the vertebral
column. Posterolateral herniation of the gelatinous nucleus
pulposus through the anulus fi brosus of an intervertebral
disc most often projects lateral to the strong attachment sites
of the posterior longitudinal ligament. If the herniated disc
compresses spinal nerve roots, then neck, back, and/or limb
pain may be present. The T2-weighted MRI clearly shows disruption
of the anterior longitudinal ligament, evident by the
abnormal hyperintense (white) signal located anterior to the
C5 vertebral body. Choice C (Ligamentum fl avum) is incorrect.
The ligamenta fl ava (L: yellow ligament) are paired ligaments
of yellow elastic fi brous tissue, which bind together
the laminae of adjoining vertebrae and form the posterior
wall of the vertebral canal. Because these ligaments resist
fl exion of the vertebral column, it is unlikely the ligamenta
fl ava were damaged in this hyperextension injury of the neck.
Choice D (Interspinous ligament) is incorrect. The interspinous
ligament is composed of fi brous bands that connect
the spinous processes of adjacent vertebrae. Because these
ligaments resist fl exion of the vertebral column, it is unlikely
the interspinous ligaments were damaged in this hyperextension
injury of the neck. Choice E (Intertransverse ligament)
is incorrect. The intertransverse ligament is one ligament
that connects the transverse processes of adjacent vertebrae.
Because the intertransverse ligaments resist contralateral bending
(abduction; lateral fl exion) of the vertebrae, it is unlikely
the intertransverse ligaments were damaged in this hyperextension
injury of the neck.

Q10) A radiologist orders a posteroanterior (PA) plain fi lm of the
chest. This image should provide the greatest resolution of
which of the following structures?

The PA plain fi lm is the standard
radiographic view of the thorax, and probably the most
commonly obtained medical image. In basic terminology, a
PA radiograph is one in which the X-ray beam penetrates from
the patient’s posterior side to the anterior side, as shown in
the given illustration. The X-ray projector is located posterior
to the patient, and the X-ray fi lm is positioned anterior. The
part of the body under study should be as close as possible to
the X-ray fi lm in order to optimize the resolution of that part
and minimize magnifi cation artifacts. Thus, in the PA orientation,
the heart is closest to the X-ray fi lm and appears sharper
than the other structures in question. Choice A (Transverse
processes of the vertebrae) is incorrect. In the PA orientation,
the vertebral column (being in the posterior aspect of
the body) is further away from the X-ray fi lm. Also, the vertebrae
are in line with several other overlapping structures (e.g., the heart, esophagus, and aorta) that add rad

Q11) A research scientist at a pharmaceutical company discovers a
new drug that selectively blocks the release of norepinephrine
from nerve endings. At which of the following sites would this
drug have the greatest effect on normal synaptic transmission?
(A) Somatic neuron motor end plates
(B) Postsynaptic parasympathetic nerve terminals
(C) Postsynaptic sympathetic nerve terminals
(D) Synapses between presynaptic and postsynaptic parasympathetic
neurons
(E) Synapses between presynaptic and postsynaptic sympathetic
neurons

Postsynaptic sympathetic neurons typically release the neurotransmitter
norepinephrine/noradrenaline from their endings,
so the sympathetic division is described as a noradrenergic
system. Blocking the release of norepinephrine would disrupt
normal neurotransmission at these terminal sites. An
important exception to this rule is that the postsynaptic sympathetic
neurons supplying sweat glands typically release
acetylcholine from their endings. Choice A (Somatic neuron
motor end plates) is incorrect. The somatic motor neurons
that supply skeletal muscle fi bers utilize acetylcholine as their
neurotransmitter at motor end plates. Choice B (Postsynaptic
parasympathetic nerve terminals) is incorrect. Postsynaptic
parasympathetic neurons typically release acetylcholine as
the neurotransmitter at their endings, so the parasympathetic
division is described as a cholinergic system. Choice D (Synapses
between presynaptic and postsynaptic parasympathetic
neurons) is incorrect. Both sympathetic and parasympathetic
divisions utilize acetylcholine as the neurotransmitter between
their presynaptic and postsynaptic cells. Choice E (Synapses
between presynaptic and postsynaptic sympathetic neurons)
is incorrect. Both sympathetic and parasympathetic divisions
utilize acetylcholine as the neurotransmitter between their
presynaptic and postsynaptic cells.

13. A 2-year-old male patient develops progressive
generalized weakness and muscle atrophy.
The impairment first began with the muscles of
the hips, and then progressed to the pelvic area,
thigh, and shoulder muscles. The patient is
diagnosed with Duchenne’s muscular dystrophy,
a congenital disorder where the protein
dystrophin is deficient. Which of the following
describes the role of dystrophin in muscle
tissue?

Dystrophin anchors actin to the sarcolemma,
reinforcing and stabilizing the latter
during muscle contraction. Titin is a large protein
which associates with myosin filaments
and endows them with elastic recoil properties
(choice B). Desmin filaments form a supportive
network extending from Z disk to Zdisk
(choice C). Troponin I inhibits the binding of
myosin to actin (choice D). AlphaB-crystallin
protects desmin filaments from stress-induced
damage (choice E).

14)A 55-year-old man with severe coughing is admitted to the hospital. Radiographic examination reveals tuberculosis of the right lung, with extension to
the thoracic vertebral bodies of T6 and T7, producing
a “gibbus deformity.” Which of the following conditions is most likely also to be confi rmed by radiographic examination?

B Kyphosis is characterized by a “hunchback”
due to an abnormal increase in curvature of the thoracic region of the vertebral column. Lordosis, or
“swayback,” is an increase in lumbar curvature of the
spine. Lordosis can be physiologic, such as seen in a
pregnant woman. Scoliosis is a lateral curvature of
the spine with rotation of the vertebrae. Spina bifida is a neural tube defect characterized by failure of closure of the vertebral arch. Osteoarthritis is a degen-
erative disorder that affects the articular cartilage of
joints and is not specifi cally related to the thoracic
region of the spine.

15) 30-year-old female patient cones to OPDcomplains of increasing muscle weakness andfatigue during the day, requiring her to takefrequent rests. She also reports that she cannotenjoy her meals any more because her musclesof mastication quickly weaken and she has tostop chewing. When she watches television atnight for a long period of time, her visionbecomes blurry and she sees double. Her neurologistmakes a preliminary diagnosis ofmyasthenia gravis. Which of the following isthe cause of myasthenia gravis?

(C) Myasthenia gravis is an autoimmune disorder
where autoantibodies target the postsynaptic
cholinergic receptors and destroy them.
Acetylcholine released from motor neurons is
thus unable to bind and the muscle contraction
weakens due to decreased neurotransmitter
communication. Acetylcholine synthesis in
motor neurons (choice A) remains normal.
Acetylcholinesterase (choice B) is the enzyme
which degrades acetylcholine and its synthesis
is not affected in myasthenia gravis. The cholinergic
neurotransmitter release mechanism
(choice D) at the presynaptic membrane, as
well as the signal transduction mechanism
within the muscle, remain normal.

15) 67 A 65-year-old patient complains of severe, chronic
pain from the region of her right hip. The patient is
admitted to the hospital and a decision is made to per￾form surgery to avoid prescribing excessive pain medi￾cation. In such a case, which would the surgeon most
likely choose to perform?
⃣ A. Division of the ventral primary rami of nerves
supplying the affected region
⃣ B. Transection of all dorsal primary rami of
nerves from the hip area
⃣ C. Removal of abdominal sympathetic chain gan￾glia on the right side
⃣ D. Transection of the dorsal rootlets of spinal
nerves supplying the right hip
⃣ E. Division of lower lumbar and sacral ventral
rootlets