Chapter 12

Question 1

The most common site of a thyroglossal
cyst is the
(A) dorsal aspect of neck
(B) anterior border of sternocleidomastoid
muscle
(C) superior mediastinum
(D) midline close to the hyoid bone
(E) base of the tongue

Answer 1

D. The thyroid gland forms from a diverticulum in the midline of the floor of the pharynx.
The thyroid migrates caudally and passes ventral to the hyoid bone. During this migration, the
thyroid remains connected to the tongue by the thyroglossal duct. If a part of the thyroglossal
duct persists, a cyst develops, usually near the hyoid bone.

Question 2

Taste sensation from the oral part (anterior
two thirds) of the tongue is predominantly carried
by the
(A) trigeminal nerve (CN V)
(B) chorda tympani branch of the facial
nerve (CN VII)
(C) glossopharyngeal nerve (CN IX)
(D) superior laryngeal branch of the vagus
nerve (CN X)
(E) recurrent laryngeal branch of the vagus
nerve (CN X)

Answer 2

B. Taste sensation from the mucosa for the oral part of the tongue is carried by the chorda tympani
branch of the facial nerve (CN VII). This part of the tongue forms from pharyngeal arch 1,
so the trigeminal nerve (CN V) will carry sensory innervation from the mucosa.

Question 3

The intermaxillary segment forms via the
fusion of the
(A) maxillary prominences
(B) mandibular prominences
(C) palatine shelves
(D) lateral nasal prominences
(E) medial nasal prominences

Answer 3

E. The intermaxillary segment, which plays a critical role in the formation of the definitive
adult palate, forms when the two medial nasal prominences fuse in the midline.

Question 4

The most common site of a pharyngeal fistula
is the
(A) dorsal aspect of neck
(B) anterior border of sternocleidomastoid
muscle
(C) superior mediastinum
(D) midline close to the hyoid bone
(E) base of the tongue

Answer 4

B. A pharyngeal fistula forms when pharyngeal pouch 2 and pharyngeal groove 2 persist.
Therefore, these fistulas are found on the lateral aspect of the neck, usually along the anterior border
of the sternocleidomastoid muscle.

Question 5

During surgery for removal of a thyroid
tumor, a number of small masses of glandular
tissue are noted just lateral to the thyroid
gland. Metastasis from the thyroid tumor is
suspected, but histologic analysis of a biopsy
reveals parathyroid tissue and remnants of thymus.
How can this finding be explained?
(A) Tumor tissue has differentiated into normal
tissue
(B) A parathyroid gland tumor is also present
(C) Ectopic glandular tissue is commonly
found in this region
(D) Patient has DiGeorge syndrome
(E) The glandular tissue is a result of a thyroglossal
duct cyst

Answer 5

C. The parathyroid and thymus migrate in a caudal and medial direction during development;
therefore, ectopic glandular tissue may be found anywhere along the migratory path.