Embryology: Pharyngeal Apparatus Flashcards
The facial bones are derived from which of the following embryonic structures?
A) Lateral plate mesoderm B) Somites C) Endoderm D) Neural crest cells E) Paraxial mesoderm
D
If the stapes fails to develop, what pharyngeal arch has been compromised?
A) First B) Second C) Third D) Fourth E) Sixth
B
The anterior 2/3rds of the tongue develops from (i) what pharyngeal arch and (ii) general sensation from this region is carried on what cranial nerve?
A) First – CN V B) First – CN VII C) Third – CN V D) Third – CN VII E) Fourth – CN V F) Fourth – CN VII
A
Mandibulofacial dysostosis (Treacher Collins syndrome) is a developmental disorder characterized by craniofacial deformities, including malformed or absent ears, zygomatic and mandibular hypoplasia, and downward slanting eyes exhibiting ptosis of the lateral eyelids. This condition is the result of lack of migration of neural crest cells into what pharyngeal arch?
A) First pharyngeal arch B) Second pharyngeal arch C) Third pharyngeal arch D) Fourth pharyngeal arch E) Fifth pharyngeal arch
A
A 36-year-old woman comes to her physician complaining of heart palpitations, weight loss, anxiety, insomnia, fatigue and amenorrhea. The physician palpates a 1.5-cm mass on her neck, which elevates when she swallows, located inferior to the cricoid cartilage yet off the midline. What is the most likely structure involved with her presentation?
A) Enlarged deep cervical lymph node B) Thyroid nodule C) Benign parathyroid adenoma D) Thyroglossal duct cyst E) Branchial cyst
B
A 10-year-old girl presents with a smooth, round neck mass the size of a golf ball at the upper third of the anterior border of her right sternocleidomastoid muscle. Her mother says that this once small, peanut-sized mass grew without pain or inflammation after it became noticeable 2 months previously. The mass does not affect the girl’s daily activities. What is the most likely diagnosis?
A) Thyroglossal duct cyst B) Branchial cyst C) Undescended thymus D) Preauricular cyst E) Ectopic palatine tonsil
B
A 17-year-old girl uses Acutane, an acne drug implicated in interfering with normal development of the facial primordial, early in her unexpected pregnancy. Examination of the newborn reveals a unilateral cleft palate. In this case, the defect is related to failure of fusion of what craniofacial processes?
A) Maxillary and medial nasal processes B) Opposite maxillary processes C) Medial and lateral nasal processes D) Maxillary and lateral nasal processes E) Opposite medial nasal processes
A
A 25-year-old woman notes an asymmetry in her neck when she tenses the skin of her inferior face and neck. This asymmetry may be due to a limited mesodermal migration in which of the following embryonic structures?
A) First pharyngeal arch B) Second pharyngeal arch C) Third pharyngeal arch D) Fourth pharyngeal arch E) Fifth pharyngeal arch
B
A newborn infant has difficulty in breastfeeding due to unilateral atrophy in the area of the face occupied by the levator labii superioris, levator anguli oris, and lateral upper part of the orbicularis oris muscles. This region of the face is derived from which of the following embryonic structures?
A) Maxillary process B) Mandibular process C) Frontal process D) Lateral nasal process E) Medial nasal process
A
If normal evagination of the endodermal lining of the embryonic pharynx does not take place between the pharyngeal arches, the pharyngeal pouches will not form. Maldevelopment of the first pharyngeal pouch during embryonic weeks 4 to 5 is most likely to result in a congenital disorder of which of the following structures?
A) Thyroid gland B) Thymus gland C) Parathyroid glands D) Facial muscles E) Tympanic cavity
E
An 8-year-old boy comes to his physician with a painless and smooth mass located in the midline of his neck at the level of the hyoid bone. This palpable, midline neck mass was asymptomatic, but due to recent expansion, it has caused difficulty and pain when swallowing. When he swallows or protrudes his tongue the mass moves superiorly. What is the most likely diagnosis?
A) Enlarged deep cervical lymph node B) Thyroid nodule C) Benign parathyroid adenoma D) Thyroglossal duct cyst E) Branchial cyst
D
Genetic testing of a baby boy with facial and cardiovascular anomalies reveals a small deletion in chromosome 22, specifically 22q11.2. This 22q11.2 deletion (DiGeorge syndrome) often results in migration defects of neural crest cells within the pharyngeal pouches. In this DiGeorge syndrome patient, the thymus and inferior parathyroid glands are absent. Which of the following pharyngeal pouches is most likely affected?
A) First B) Second C) Third D) Fourth E) Fifth
C
A physician examines a 53-year-old woman and notes deviation of the uvula to the right and asymmetry in the elevation of the soft palate, with the palatal arch of the left side sagging when compared to the right. The muscles involved in these abnormal findings are most likely derived from the mesoderm of what pharyngeal arch?
A) First B) Second C) Third D) Fourth E) Sixth
D
