Download 1. Following thyroid surgery, it was noted that a patient frequently

1. Following thyroid surgery, it was noted that a patient frequently
aspirated fluid into her lungs. Upon examination it was determined
that the area of the piriform recess above the vocal fold of the
larynx was numb. What nerve may have been injured?
External branch of the superior pharyngeal
Hypoglossal
Internal branch of the superior laryngeal
Lingual
Recurrent laryngeal
2. The laryngeal muscle most responsible for stretching (elongating)
the vocal ligament is the :
Posterior cricoarytenoid
Lateral cricoarytenoid
Thyroarytenoid
Arytenoid
Cricothyroid
3. The muscle most responsible for the abduction of the vocal folds is
the :
Arytenoid
Cricothyroid
Lateral cricoarytenoid
Posterior cricoarytenoid
Thyroarytenoid
4. The nerve that innervates all but one muscle of larynx is the:
Glossopharyngeal nerve, pharyngeal branch
Inferior laryngeal nerve
Superior laryngeal nerve, external branch
Superior laryngeal nerve, internal branch
Thyrohyoid nerve
5. The vocalis muscle is most responsible for the fine control of
phonation because of its attachment into the:
Arytenoid cartilage
Cricoid cartilage
Thyroid cartilage
Vestibular ligament
Vocal ligament
6. The constrictor muscles of the pharynx receive their motor nerve
supply from the:
Glossopharyngeal nerve
Hypoglossal nerve
Spinal accessory nerve
Sympathetic trunk
Vagus nerve
7. Twenty-four hours following a partial thyroidectomy where the
inferior thyroid artery was also ligated (tied off), the patient now
spoke with a hoarse voice (whisper), and had difficulty in
breathing. Which nerve was injured?
Internal branch of superior laryngeal
Ansa cervicalis
Ansa subclavia
Recurrent laryngeal
External branch of superior laryngeal
8. In performing a thyroidectomy, caution should be exercised when
ligating (tying) the inferior thyroid artery, as it lies in a very close
relationship to which nerve?
ansa cervicalis
hypoglossal
phrenic
recurrent laryngeal
vagus
9. A 60-year-old man has occasional blackouts and lightheadedness. Studies reveal atherosclerotic plaques within the
common carotid arteries and the bifurcation of the vessels. A
carotid endartectomy is undertaken. Which nerve bundle running
vertically within the carotid sheath must the surgeon be careful not
to injure?
Accessory
Cervical sympathetic trunk
Glossopharyngeal
Hypoglossal
Vagus
10.
A 55-year-old woman has difficulty swallowing and frequently
aspirates fluids while drinking. She is diagnosed as having a skull
base tumor occupying the space behind the jugular foramen.
Involvement of which structure is responsible for the findings?
Ansa cervicalis
Cervical sympathetic trunk
Accessory nerve
Hypoglossal nerve
Vagus
11.
While doing a postoperative physical on a patient who has
undergone carotid endarterectomy on the right side, it was noted
that the tongue deviated toward the right when the patient was
asked to point the tongue outward. What nerve crossing the
carotid artery must have been injured?
Glossopharyngeal
Hypoglossal
Inferior alveolar
Lingual
Vagus
12.
Any manipulation of the superior thyroid artery must be
undertaken with care not to damage its small companion nerve,
the:
Cervical sympathetic trunk
External branch of the superior laryngeal
Inferior root of the ansa cervicalis
Internal branch of the superior laryngeal
13.
Recurrent laryngeal
The carotid body is innervated by a branch of the:
Glossopharyngeal nerve
Hypoglossal nerve
Spinal accessory nerve
Sympathetic trunk
Vagus nerve
1. The correct answer is:
Internal branch of the superior laryngeal
The internal branch of the superior laryngeal is a sensory nerve that
pierces the thyrohyoid membrane along with the superior laryngeal
artery. It supplies sensory fibers to the mucous membrane of the larynx,
superior to the vocal folds. Since this area lost sensation, it appears that
the internal branch of the superior laryngeal nerve must have been
injured. The external branch of the superior laryngeal nerve is a motor
nerve that innervates the cricothyroid muscle--it does not provide any
sensory innervation to the larynx. The recurrent laryngeal nerve ascends
from the thorax and provides motor innervation to the upper esophagus,
lower pharynx, and all the laryngeal muscles except cricothyroideus.
The hypoglossal nerve supplies motor innervation to the muscles of the
tongue. The lingual nerve is a sensory nerve for the anterior 2/3 of the
tongue. These nerves are not important for innervating the larynx.
2. The correct answer is:
Cricothyroid
Cricothyroid draws the thyroid cartilage forward, tensing the vocal
ligaments. This is the one muscle innervated by the external branch of
the superior laryngeal nerve. Posterior cricoarytenoid is a very important
muscle; it's the only muscle that abducts the vocal folds. This muscle is
innervated by the inferior laryngeal nerve, which is a continuation of the
recurrent laryngeal nerve. If this muscle is denervated, the vocal folds
may be paralyzed in an adducted position, which would prevent air from
entering the trachea. Lateral cricoarytenoid, thyroarytenoid, and
arytenoid are all muscles that adduct the vocal folds. They are all
innervated by the inferior laryngeal nerve.
3. The correct answer is:
Posterior cricoarytenoid
The posterior cricoarytenoid is the only muscle that abducts the vocal
folds. This muscle is innervated by the inferior laryngeal nerve, which is
a continuation of the recurrent laryngeal nerve. If this muscle is
denervated, the vocal folds may be paralyzed in an adducted position,
which would prevent air from entering the trachea. Arytenoid, lateral
cricoarytenoid, and thyroarytenoid all adduct the vocal folds. Cricothyroid
is the only laryngeal muscle innervated by the external branch of the
superior laryngeal. It tenses the vocal ligaments by tipping the thyroid
cartilage forward relative to the cricoid cartilage.
4. The correct answer is:
Inferior laryngeal nerve
The inferior laryngeal nerve is the continuation of the recurrent laryngeal
nerve, superior to the inferior border of the cricoid cartilage. It innervates
the posterior cricoarytenoid muscle, which is responsible for abducting
the vocal folds. The inferior laryngeal nerve also innervates all of the
other intrinsic muscles of the larynx, with the exception of the
cricothyroid muscle. The pharyngeal branch of the glossopharyngeal
nerve provides sensory innervation to the pharynx, but not to the larynx.
The glossopharyngeal nerve only provides motor innervation to
stylopharyngeus. The external branch of the superior laryngeal nerve
innervates the cricothyroid muscle, which is responsible for stretching
the vocal ligaments. The internal branch of the superior laryngeal nerve
is responsible for providing sensory innervation to the mucosa of the
larynx, superior to the true vocal fold. The thyrohyoid nerve is a branch
of ansa cervicalis-- it innervates the thyrohyoid muscle, which elevates
the larynx and depresses the hyoid bone (or helps to fix the hyoid in
space, so that other muscles, such as tongue muscles, can work).
5. The correct answer is:
Vocal ligament
Vocalis represents the innermost fibers of the thyroarytenoid muscle,
from the inner surface of the thyroid cartilage. Because vocalis inserts
on the vocal ligament, it can relax very specific segments of the vocal
ligament to adjust the pitch. Although there are many muscles that insert
on the other pieces of cartilage listed, vocalis is the only one that can
provide for such fine control of tone because it is inserting right on the
vocal ligament.
6. The correct answer is:
Vagus nerve (CN X)
The vagus nerve supplies motor innervation to the muscles of the larynx
and pharynx, with the exception of stylopharyngeus (innervated by the
glossopharyngeal nerve). It also supplies motor innervation to the palate
muscles, with the exception of tensor veli palatini (innervated by the V3
division of the trigeminal nerve). The glossopharyngeal nerve (CN IX)
provides the sensory, but not motor, innervation to the pharynx. The
hypoglossal nerve (CN XII) provides motor innervation to the muscles of
the tongue. The accessory nerve (CN XI) provides motor innervation to
the trapezius and the sternocleidomastoid. Finally, the sympathetic trunk
supplies sympathetic innervation to the head and neck.
7. The correct answer is:
Recurrent laryngeal
The recurrent laryngeal nerve runs with the inferior thyroid artery toward
the lower lobes of the thyroid. This means that the recurrent laryngeal
nerve would be at risk in any surgery involving the inferior thyroid artery
or the inferior poles of the thyroid. The recurrent laryngeal nerve
becomes the inferior laryngeal nerve at the inferior border of cricoid
cartilage, and this nerve continues on to innervate all the muscles of the
larynx with the exception of cricothyroid. So, an injury to the recurrent
laryngeal nerve might lead to hoarseness and difficulty breathing (due to
a laryngeal spasm).
The internal branch of superior laryngeal runs with the superior laryngeal
artery and pierces the thyrohyoid membrane. Ansa cervicalis is a branch
of the cervical plexus which hangs in front of the internal jugular vein. It
innervates the strap muscles, not the laryngeal muscles. Ansa subclavia
is part of the sympathetic trunk which loops around the subclavian
artery. Finally, the external branch of the superior laryngeal nerve runs
with the superior thyroid artery. This is the artery and nerve that might be
damaged when removing the superior lobe of the thyroid.
8. The correct answer is:
recurrent laryngeal
The recurrent laryngeal nerve crosses the inferior thyroid artery near the
lower lobe of the thyroid. This means that the recurrent laryngeal nerve
would be at risk in any surgery involving the inferior thyroid artery or the
inferior poles of the thyroid. The recurrent laryngeal nerve becomes the
inferior laryngeal nerve at the inferior border of cricopharyngeus, and
this nerve continues on to innervate all the muscles of the larynx with the
exception of cricothyroid. So, you really need to take care to protect the
recurrent laryngeal nerve--injuring this structure could lead to
hoarseness, permanent loss of voice, or even death due to a laryngeal
spasm.
None of the other listed nerves are related to the inferior thyroid artery.
Ansa cervicalis is a branch of the cervical plexus which hangs in front of
the internal jugular vein. It innervates the strap muscles. The
hypoglossal nerve winds behind the internal jugular vein, then sweeps
around lateral to the carotid vessels and into the floor of the mouth,
where it innervates the tongue muscles. The phrenic nerve lies on top of
the anterior scalene muscles--it then travels through the thorax to
innervate the diaphragm. Finally, the vagus is found in the carotid
sheath--it is associated with the common carotid and the internal carotid
arteries.
9. The correct answer is:
Vagus
In a carotid endarterectomy, surgeons enter the carotid artery and
excise the diseased endothelium and media of the artery so that the
lumen is left with a smooth lining. To do this, the surgeons must enter
the carotid sheath, which means that any structure within that sheath or
near that sheath might be injured. This question specifically asks which
structure in the sheath could be injured, so the correct answer is the
vagus nerve. The carotid sheath contains 2 nerves: the vagus and the
superior ramus of ansa cervicalis. It also contains 3 vessels: internal
carotid, common carotid, and internal jugular vein. Any of these
structures could be damaged during the procedure.
The accessory nerve is most closely associated with the posterior
triangle of the neck. It cuts through this triangle to innervate
sternocleidomastoid and trapezius and lies posterior to the carotid
vessels The cervical sympathetic trunk lies in front of the prevertebral
muscles in the prevertebral fascia. The glossopharyngal nerve comes
out of the jugular foramen and divides into 2 branches--pharyngeal and
lingual branches. This nerve sweeps near the carotid sheath, but it's not
in the carotid sheath. The hypoglossal nerve travels lateral to the carotid
vessels before entering the floor of the mouth. It crosses the carotid
artery, but it's not in the sheath.
10. The correct answer is:
Vagus
The vagus nerve, which exits the skull through the jugular foramen, is
the motor nerve to the pharynx. So, it allows for swallowing. This
patient's symptoms and the location of the tumor clearly point to an
injury of the vagus nerve. The accessory nerve also exits the skull
through the jugular foramen--it could be injured from this tumor, but the
symptoms are not suggestive of an accessory nerve injury. If her
accessory nerve was damaged, the patient's sternocleidomastoid and
trapezius would be denervated, which means the acromion of her
shoulder would sag. The other nerve that comes through the jugular
foramen is the glossopharyngeal nerve--this nerve might also be
damaged by the tumor.
The other nerves listed do not come from the jugular foramen, so they
would not be the first nerves injured by the tumor. Ansa cervicalis is a
branch of the cervical plexus that innervates the strap muscles in the
anterior neck. The cervical sympathetic trunk is the structure that
provides sympathetic innervation to the head and neck. If this trunk was
disrupted, the patient would have Horner's syndrome. The symptoms of
Horner's syndrome include: ptosis, constricted pupil, lack of sweating on
the affected side, flushing on the affected side, and enophthalmos
(sunken-in eye). Finally, the hypoglossal nerve exits the skull through
the hypoglossal canal, providing motor innervation to the muscles of the
tongue. An injury to the hypoglossal nerve would cause the tongue,
when protruded, to point to the side of the face with the injured nerve.
11. The correct answer is:
Hypoglossal
The hypoglossal nerve crosses the carotid artery before diving into the
floor of the mouth, so it might get injured during this procedure. This
nerve innervates the muscles of the tongue. When the hypoglossal
nerve is injured and a patient sticks out the tongue, the tongue points to
the side with the injured nerve. So, this patient, who had the right side
endarctectomy, has an injury to the right hypoglossal nerve. The
symptoms that you see in this case should point you toward suspecting
damage to the hypoglossal nerve.
The glossopharyngeal nerve crosses around the internal carotid artery
and the stylopharyngeus muscle--it could theoretically be injured in this
procedure, but the symptoms are not consistent with an injury to this
structure. The inferior alveolar nerve and lingual nerves are branches of
the mandibular division of the trigeminal nerve. They are not associated
with the carotid vessels. The vagus nerve is found in the carotid sheath.
This nerve can be easily injured by an endarterectomy, although
damage to the vagus would cause problems with swallowing, not with
tongue movements.
12. The correct answer is:
External branch of the superior laryngeal
The external branch of the superior laryngeal nerve runs with the
superior thyroid artery--this artery and nerve might be damaged when
removing the superior pole of the thyroid. If this nerve was damaged, the
cricothyroid muscle would be paralyzed, and a patient would be unable
to tense the vocal cords. The internal branch of the superior laryngeal
nerve runs with the superior laryngeal artery and provides sensory
innervation to the mucous membrane of the larynx, superior to the vocal
fold. The recurrent laryngeal nerve crosses the inferior thyroid artery,
near the lower pole of the thyroid. This means that the recurrent
laryngeal nerve would be at risk in any surgery involving the inferior
thyroid artery or the inferior poles of the thyroid. The recurrent laryngeal
innervates all the muscles of the larynx with the exception of
cricothyroid. So, an injury to the recurrent laryngeal nerve might lead to
hoarseness and dificulty breathing.
The cervical sympathetic trunk lies in front of the prevertebral muscles in
the prevertebral fascia--it would not be near the structures involved with
thyroid surgery. The inferior root of ansa cervicalis is a branch of the
cervical plexus. It innervates the strap muscles. Ansa cervicalis hangs in
a loop over the carotid vessels; it is not associated with the thyroid
gland.
13. The correct answer is:
Glossopharyngeal nerve (CN IX)
The carotid body is innervated by the carotid branch of the
glossopharyngeal nerve. It is a small, reddish-brown ovoid mass that lies
on the medial side of the carotid bifurcation, serving as a chemoreceptor
that monitors the level of carbon dioxide in the blood. The hypoglossal
nerve (CN XII) innervates the muscles of the tongue. The spinal
accessory nerve is a motor nerve that innervates the
sternocleidomastoid and the trapezius. The sympathetic trunk provides
sympathetic innervation to the head and neck. Finally, the vagus nerve
supplies motor innervation to the muscles of the pharynx and larynx,
with the exception of stylopharyngeus, and the muscles of the palate,
with the exception of tensor veli palatini.