Gray's Anatomy Review - Head and
Neck Exam Questions and Answers
A 2-month-old male infant presents with a small pit at the anterior border of his left
sternocleidomastoid muscle, with mucus dripping intermittently from the opening.
The pit extended to the tonsillar fossa as a branchial fistula. Which of the following
embryologic structure(s) is (are) involved in this anomaly?
A. Second pharyngeal arch
B. Second pharyngeal pouch and groove
C. Third pharyngeal pouch
D. Thyroglossal duct
E. Second pharyngeal pouch and cervical sinus - answer- 1 E. The child in this case
suffers from a fistula that indicates an open malformation. This implies that the defect
must be due to failure of closure for both an internal and an external structure. This
excludes the second pharyngeal arch and third pharyngeal pouch from being the
answers alone. A branchial fistula results from failure of closure of both the second
pharyngeal pouch and the cervical sinus, the cervical sinus being the consolidation
of the second through fourth pharyngeal clefts, all being external structures. The
thyroglossal duct extends from the thyroid to the tongue and failure of its closure
would not result in an external defect. The second pharyngeal groove merges with
the third and fourth pharyngeal grooves to form the cervical sinus. Failure of closure
of the second groove alone would not present with an open fistula. GAS 1016; N 64;
McM 28-35
A 2-day-old female infant was born with a cleft palate. The major portion of the
palate develops from which of the following embryonic structures?
A. Lateral palatine process
B. Median palatine process
C. Intermaxillary segment
D. Median nasal prominences
E. Frontonasal eminence - answer- 2 A. The largest part of the palate is formed by
the secondary palate, which is embryologically derived from the lateral palatine
processes. The median palatine process gives rise to the smaller primary palate,
located anteriorly. The intermaxillary segment gives rise to the middle upper lip,
premaxillary part of the maxilla, and the primary palate. The median nasal
prominences merge with each other and the maxillary prominences to give rise to
the intermaxillary segment. The frontonasal eminence gives rise to parts of the
forehead, nose, and eyes. GAS 1089, 1077; N 62, 64; McM 1, 9
A 3-day-old male infant has a small area of the right iris missing, and a diagnosis of
coloboma of the iris is made. Which of the following is the most likely embryologic
cause of the coloboma?
A. Failure of the retinal/choroid fissure to close
B. Abnormal neural crest formation
C. Abnormal interactions between the optic vesicle and ectoderm
D. Posterior chamber cavitation
,E. Weak adhesion between the inner and outer layers of the optic vesicle - answer- 3
A. A coloboma of the iris is caused by failure of the retinal fissure to close during the
sixth week. Abnormal neural crest formation would lead to abnormal development of
choroid, sclera, and cornea because these are derived from neural crest cells.
Abnormal interaction between the optic vesicle and ectoderm would lead to
abnormal development of the entire eye because a lens placode may fail to develop
or develop abnormally. The iris would not be affected by abnormal development of
the posterior chamber. Weak adhesion between the layers of the optic vesicle leads
to congenital retinal detachment. GAS 947; N 83; McM 54
Early closure of the fontanelles of the infant skull can result in compression of the
brain, restricting brain growth. Which of the following fontanelles is located at the
junction of the sagittal and coronal sutures and at what age does this fontanelle
typically close?
A. Posterior fontanelle, which closes at about 2 years
B. Mastoid fontanelle, which closes at about 16 months
C. Lambdoid fontanelle, which closes at 8 months to 1 year
D. Sphenoidal fontanelle, which closes at 3 years
E. Anterior fontanelle, which closes at 18 months - answer- 4 E. The anterior
fontanelle is located at the junction of the sagittal and coronal sutures and closes at
around 18 months of age. The posterior fontanelle is located at the junction of the
sagittal suture and lambdoid suture, and it closes at around 2 to 3 months. The
mastoid fontanelle is located at the junction of the squamous suture and the
lambdoid suture, and it closes at the end of the first year. The sphenoidal fontanelle
is located at the junction of the squamous suture and the coronal suture and closes
at around 2 to 3 months. There is a lambdoid suture but not a lambdoid fontanelle.
GAS 860, 864; N 9; McM 14
A 3-year-old boy is admitted to the hospital because of a soft anterior midline
cervical mass. When he is asked to protrude his tongue, the mass in the neck is
observed to move upward. Which of the following is the most likely diagnosis?
A. A thyroglossal duct cyst
B. Defect in sixth pharyngeal arch
C. A branchial cyst
D. Cystic fistula of the third pharyngeal arch
E. Defect in first pharyngeal arch - answer- 5 A. Thyroglossal duct cysts occur due to
retention of a remnant of the thyroglossal duct along the path followed by the
descending thyroid gland during development. The path begins at the foramen
cecum of the tongue and descends in the midline to the final position of the thyroid.
The sixth pharyngeal arch provides origin to muscles and cartilage of the neck and
would produce a midline mass connected to the tongue. A branchial cyst or fistula
would not be present in the midline. The first pharyngeal arch gives rise to muscles
of mastication and the malleus and incus. The third pharyngeal arch provides origin
to the stylopharyngeus muscle and hyoid bone. GAS 1020; N 64; McM 33
A 2-day-old male infant has a noticeable gap in his upper lip. The diagnosis is a cleft
lip. Failure of fusion of which of the following structures is the most likely cause of
this anomaly?
A. Lateral nasal and maxillary prominences/ processes
B. Medial nasal prominences/processes
,C. Lateral nasal and medial nasal prominences/ processes
D. Lateral prominences/processes
E. Maxillary prominences/processes and the intermaxillary segment - answer- 6 E.
The most common cause of cleft lip is failure of fusion of the maxillary process and
the intermaxillary segment. Defects located between the lateral nasal prominences
and the maxillary processes would affect the development of the nasolacrimal duct.
Failure of fusion of the medial nasal prominences would produce a median cleft lip, a
rare congenital anomaly. The lateral and median nasal processes both arise from the
nasal placodes and do not undergo subsequent fusion. The lateral nasal
prominences do not fuse with each other. GAS 1077; N 46; McM 80
A 3-day-old male infant has a noticeably small mandible. A computed tomography
(CT) scan and physical examinations reveal hypoplasia of the mandible, cleft palate,
and defects of the eye and ear. Abnormal development of which of the following
pharyngeal arches will most likely produce such symptoms?
A. First arch
B. Second arch
C. Third arch
D. Fourth arch
E. Sixth arch - answer- 7 A. The listed symptoms are typical of first pharyngeal
(brachial) arch syndrome because the first arch normally gives rise to muscles of
mastication, mylohyoid, anterior belly of the digastric, tensor tympani, tensor veli
palatini, malleus, and the incus. Abnormal development of the second arch would
affect the muscles of facial expression, the stapes, and parts of the hyoid bone.
Abnormal development of the third pharyngeal arch would affect only the
stylopharyngeus muscle and parts of the hyoid bone. Abnormal development of the
fourth and sixth arch would affect various muscles and cartilages of the larynx and
pharynx and would not produce the hypoplastic mandible characteristic of first arch
syndrome. GAS 977, 961, 1009; N 48-49, 74, 94; McM 35, 39, 61
A 5-day-old male infant has an abnormally large head. A CT scan examination
reveals enlarged lateral and third ventricles but a fourth ventricle of normal size.
Stenosis of the cerebral aqueduct (of Sylvius) is suspected. Which of the following
conditions will be characteristic of these symptoms?
A. Nonobstructive hydrocephalus
B. Anencephaly
C. Obstructive hydrocephalus
D. Meroanencephaly
E. Holoprosencephaly - answer- 8 C. Obstructive hydrocephalus, in this case
resulting from obstruction of the cerebral aqueduct (of Sylvius), refers to a condition
in which flow of cerebrospinal fluid (CSF) is obstructed within the ventricular system.
This leads to pressure increasing in the CSF upstream from the obstruction,
expanding the lateral and third ventricles. Nonobstructive hydrocephalus is due to
either excessive CSF production or ineffective CSF reabsorption. This would lead to
enlargement of all ventricular chambers. Anencephaly, also known as
meroanencephaly, is a partial absence of the brain and is due to defective closure of
the anterior neuropore. Holoprosencephaly is a failure of cleavage of the forebrain
and would result in a single fused ventricle. GAS 877-878; N 147; McM 72, 81
, A 3-month-old male infant has a lump in his neck. A biopsy of the lump shows it to
be thymic tissue. Based on embryonic origin, which of the following additional
structures is most likely to have an ectopic location?
A. Jugulodigastric lymph node
B. Lingual tonsil
C. Parathyroid gland
D. Submandibular gland
E. Thyroid gland - answer- 9 C. Both the inferior parathyroid glands and the thymus
are derived from the third pharyngeal (brachial) pouch. Therefore, an ectopic thymus
is likely to be associated with ectopic parathyroid tissue, indicating abnormal
development of the third pharyngeal pouch. The lingual tonsil develops from an
aggregation of lymph nodules on the tongue and is not associated with development
of the thymus. The submandibular gland develops from endodermal buds in the floor
of the stomodeum and is not associated with development of the thymus. The thyroid
gland arises from an outpocketing of the floor of the primitive oral cavity, descending
along the route of the thyroglossal duct, and it is not associated with development of
the thymus. Development of the lymph nodes is also not associated with
development of the thymus. GAS 1022; N 78; McM 30
A 3-month-old male infant is under observation in the pediatric clinic. The patient has
congenital hypoparathyroidism, thyroid hypoplasia, and no thymus. Abnormal
development of which of the following pharyngeal pouches or arches will most likely
produce these defects?
A. First and second
B. Second and third
C. Third and fourth
D. Fourth
E. Fourth and sixth - answer- 10 C. The defect is likely in the development of third
and fourth pharyngeal pouches because the superior parathyroid glands are derived
from the fourth pouch, whereas the inferior parathyroid glands are derived from the
third pouch. In addition, the third pouch gives rise to the thymus, and the
parafollicular cells of the thyroid gland are derived from the fourth pharyngeal pouch.
The first pouch gives rise to the tympanic membrane and cavity. The second pouch
gives rise to the palatine tonsils and tonsillar sinus. GAS 1022; N 78; McM 30
Cleft lip, with or without cleft palate, occurs about once in 1000 births. Which of the
following is considered to be the most important causative factor in the production of
this anomaly?
A. Riboflavin deficiency
B. Infectious disease
C. Mutant genes
D. Cortisone administration during pregnancy
E. Irradiation - answer- 11 C. Whereas all forms of clefts are considered to have a
multifactorial etiology, cleft lip in particular seems to have a strong genetic factor.
This has been determined using studies of twins. The other listed factors may or may
not play a role in the development of a cleft lip, but genetics remains the most
important determining factor. GAS 1077; N 46; McM 80
A 5-week-old male infant is born without a thymus or inferior parathyroid glands.
Which of the following pharyngeal arches is most likely involved?
Neck Exam Questions and Answers
A 2-month-old male infant presents with a small pit at the anterior border of his left
sternocleidomastoid muscle, with mucus dripping intermittently from the opening.
The pit extended to the tonsillar fossa as a branchial fistula. Which of the following
embryologic structure(s) is (are) involved in this anomaly?
A. Second pharyngeal arch
B. Second pharyngeal pouch and groove
C. Third pharyngeal pouch
D. Thyroglossal duct
E. Second pharyngeal pouch and cervical sinus - answer- 1 E. The child in this case
suffers from a fistula that indicates an open malformation. This implies that the defect
must be due to failure of closure for both an internal and an external structure. This
excludes the second pharyngeal arch and third pharyngeal pouch from being the
answers alone. A branchial fistula results from failure of closure of both the second
pharyngeal pouch and the cervical sinus, the cervical sinus being the consolidation
of the second through fourth pharyngeal clefts, all being external structures. The
thyroglossal duct extends from the thyroid to the tongue and failure of its closure
would not result in an external defect. The second pharyngeal groove merges with
the third and fourth pharyngeal grooves to form the cervical sinus. Failure of closure
of the second groove alone would not present with an open fistula. GAS 1016; N 64;
McM 28-35
A 2-day-old female infant was born with a cleft palate. The major portion of the
palate develops from which of the following embryonic structures?
A. Lateral palatine process
B. Median palatine process
C. Intermaxillary segment
D. Median nasal prominences
E. Frontonasal eminence - answer- 2 A. The largest part of the palate is formed by
the secondary palate, which is embryologically derived from the lateral palatine
processes. The median palatine process gives rise to the smaller primary palate,
located anteriorly. The intermaxillary segment gives rise to the middle upper lip,
premaxillary part of the maxilla, and the primary palate. The median nasal
prominences merge with each other and the maxillary prominences to give rise to
the intermaxillary segment. The frontonasal eminence gives rise to parts of the
forehead, nose, and eyes. GAS 1089, 1077; N 62, 64; McM 1, 9
A 3-day-old male infant has a small area of the right iris missing, and a diagnosis of
coloboma of the iris is made. Which of the following is the most likely embryologic
cause of the coloboma?
A. Failure of the retinal/choroid fissure to close
B. Abnormal neural crest formation
C. Abnormal interactions between the optic vesicle and ectoderm
D. Posterior chamber cavitation
,E. Weak adhesion between the inner and outer layers of the optic vesicle - answer- 3
A. A coloboma of the iris is caused by failure of the retinal fissure to close during the
sixth week. Abnormal neural crest formation would lead to abnormal development of
choroid, sclera, and cornea because these are derived from neural crest cells.
Abnormal interaction between the optic vesicle and ectoderm would lead to
abnormal development of the entire eye because a lens placode may fail to develop
or develop abnormally. The iris would not be affected by abnormal development of
the posterior chamber. Weak adhesion between the layers of the optic vesicle leads
to congenital retinal detachment. GAS 947; N 83; McM 54
Early closure of the fontanelles of the infant skull can result in compression of the
brain, restricting brain growth. Which of the following fontanelles is located at the
junction of the sagittal and coronal sutures and at what age does this fontanelle
typically close?
A. Posterior fontanelle, which closes at about 2 years
B. Mastoid fontanelle, which closes at about 16 months
C. Lambdoid fontanelle, which closes at 8 months to 1 year
D. Sphenoidal fontanelle, which closes at 3 years
E. Anterior fontanelle, which closes at 18 months - answer- 4 E. The anterior
fontanelle is located at the junction of the sagittal and coronal sutures and closes at
around 18 months of age. The posterior fontanelle is located at the junction of the
sagittal suture and lambdoid suture, and it closes at around 2 to 3 months. The
mastoid fontanelle is located at the junction of the squamous suture and the
lambdoid suture, and it closes at the end of the first year. The sphenoidal fontanelle
is located at the junction of the squamous suture and the coronal suture and closes
at around 2 to 3 months. There is a lambdoid suture but not a lambdoid fontanelle.
GAS 860, 864; N 9; McM 14
A 3-year-old boy is admitted to the hospital because of a soft anterior midline
cervical mass. When he is asked to protrude his tongue, the mass in the neck is
observed to move upward. Which of the following is the most likely diagnosis?
A. A thyroglossal duct cyst
B. Defect in sixth pharyngeal arch
C. A branchial cyst
D. Cystic fistula of the third pharyngeal arch
E. Defect in first pharyngeal arch - answer- 5 A. Thyroglossal duct cysts occur due to
retention of a remnant of the thyroglossal duct along the path followed by the
descending thyroid gland during development. The path begins at the foramen
cecum of the tongue and descends in the midline to the final position of the thyroid.
The sixth pharyngeal arch provides origin to muscles and cartilage of the neck and
would produce a midline mass connected to the tongue. A branchial cyst or fistula
would not be present in the midline. The first pharyngeal arch gives rise to muscles
of mastication and the malleus and incus. The third pharyngeal arch provides origin
to the stylopharyngeus muscle and hyoid bone. GAS 1020; N 64; McM 33
A 2-day-old male infant has a noticeable gap in his upper lip. The diagnosis is a cleft
lip. Failure of fusion of which of the following structures is the most likely cause of
this anomaly?
A. Lateral nasal and maxillary prominences/ processes
B. Medial nasal prominences/processes
,C. Lateral nasal and medial nasal prominences/ processes
D. Lateral prominences/processes
E. Maxillary prominences/processes and the intermaxillary segment - answer- 6 E.
The most common cause of cleft lip is failure of fusion of the maxillary process and
the intermaxillary segment. Defects located between the lateral nasal prominences
and the maxillary processes would affect the development of the nasolacrimal duct.
Failure of fusion of the medial nasal prominences would produce a median cleft lip, a
rare congenital anomaly. The lateral and median nasal processes both arise from the
nasal placodes and do not undergo subsequent fusion. The lateral nasal
prominences do not fuse with each other. GAS 1077; N 46; McM 80
A 3-day-old male infant has a noticeably small mandible. A computed tomography
(CT) scan and physical examinations reveal hypoplasia of the mandible, cleft palate,
and defects of the eye and ear. Abnormal development of which of the following
pharyngeal arches will most likely produce such symptoms?
A. First arch
B. Second arch
C. Third arch
D. Fourth arch
E. Sixth arch - answer- 7 A. The listed symptoms are typical of first pharyngeal
(brachial) arch syndrome because the first arch normally gives rise to muscles of
mastication, mylohyoid, anterior belly of the digastric, tensor tympani, tensor veli
palatini, malleus, and the incus. Abnormal development of the second arch would
affect the muscles of facial expression, the stapes, and parts of the hyoid bone.
Abnormal development of the third pharyngeal arch would affect only the
stylopharyngeus muscle and parts of the hyoid bone. Abnormal development of the
fourth and sixth arch would affect various muscles and cartilages of the larynx and
pharynx and would not produce the hypoplastic mandible characteristic of first arch
syndrome. GAS 977, 961, 1009; N 48-49, 74, 94; McM 35, 39, 61
A 5-day-old male infant has an abnormally large head. A CT scan examination
reveals enlarged lateral and third ventricles but a fourth ventricle of normal size.
Stenosis of the cerebral aqueduct (of Sylvius) is suspected. Which of the following
conditions will be characteristic of these symptoms?
A. Nonobstructive hydrocephalus
B. Anencephaly
C. Obstructive hydrocephalus
D. Meroanencephaly
E. Holoprosencephaly - answer- 8 C. Obstructive hydrocephalus, in this case
resulting from obstruction of the cerebral aqueduct (of Sylvius), refers to a condition
in which flow of cerebrospinal fluid (CSF) is obstructed within the ventricular system.
This leads to pressure increasing in the CSF upstream from the obstruction,
expanding the lateral and third ventricles. Nonobstructive hydrocephalus is due to
either excessive CSF production or ineffective CSF reabsorption. This would lead to
enlargement of all ventricular chambers. Anencephaly, also known as
meroanencephaly, is a partial absence of the brain and is due to defective closure of
the anterior neuropore. Holoprosencephaly is a failure of cleavage of the forebrain
and would result in a single fused ventricle. GAS 877-878; N 147; McM 72, 81
, A 3-month-old male infant has a lump in his neck. A biopsy of the lump shows it to
be thymic tissue. Based on embryonic origin, which of the following additional
structures is most likely to have an ectopic location?
A. Jugulodigastric lymph node
B. Lingual tonsil
C. Parathyroid gland
D. Submandibular gland
E. Thyroid gland - answer- 9 C. Both the inferior parathyroid glands and the thymus
are derived from the third pharyngeal (brachial) pouch. Therefore, an ectopic thymus
is likely to be associated with ectopic parathyroid tissue, indicating abnormal
development of the third pharyngeal pouch. The lingual tonsil develops from an
aggregation of lymph nodules on the tongue and is not associated with development
of the thymus. The submandibular gland develops from endodermal buds in the floor
of the stomodeum and is not associated with development of the thymus. The thyroid
gland arises from an outpocketing of the floor of the primitive oral cavity, descending
along the route of the thyroglossal duct, and it is not associated with development of
the thymus. Development of the lymph nodes is also not associated with
development of the thymus. GAS 1022; N 78; McM 30
A 3-month-old male infant is under observation in the pediatric clinic. The patient has
congenital hypoparathyroidism, thyroid hypoplasia, and no thymus. Abnormal
development of which of the following pharyngeal pouches or arches will most likely
produce these defects?
A. First and second
B. Second and third
C. Third and fourth
D. Fourth
E. Fourth and sixth - answer- 10 C. The defect is likely in the development of third
and fourth pharyngeal pouches because the superior parathyroid glands are derived
from the fourth pouch, whereas the inferior parathyroid glands are derived from the
third pouch. In addition, the third pouch gives rise to the thymus, and the
parafollicular cells of the thyroid gland are derived from the fourth pharyngeal pouch.
The first pouch gives rise to the tympanic membrane and cavity. The second pouch
gives rise to the palatine tonsils and tonsillar sinus. GAS 1022; N 78; McM 30
Cleft lip, with or without cleft palate, occurs about once in 1000 births. Which of the
following is considered to be the most important causative factor in the production of
this anomaly?
A. Riboflavin deficiency
B. Infectious disease
C. Mutant genes
D. Cortisone administration during pregnancy
E. Irradiation - answer- 11 C. Whereas all forms of clefts are considered to have a
multifactorial etiology, cleft lip in particular seems to have a strong genetic factor.
This has been determined using studies of twins. The other listed factors may or may
not play a role in the development of a cleft lip, but genetics remains the most
important determining factor. GAS 1077; N 46; McM 80
A 5-week-old male infant is born without a thymus or inferior parathyroid glands.
Which of the following pharyngeal arches is most likely involved?
