Pharyngeal arches Practice Questions

Question 1

A 1-year-old girl born to a 40-year-old woman is undergoing an examination by a pediatric resident in the hospital. The pregnancy was uneventful and there were no complications during the delivery. The physical examination reveals midface hypoplasia with a flat nasal bridge and upslanting palpebral fissures. She has a small mouth and chest auscultation reveals a blowing holosystolic murmur that is heard best along the sternal border. The family history is unremarkable. A karyotype analysis is ordered because the resident suspects a numerical chromosomal disorder. Which of the following phenomena leads to the infant’s condition?

Accepted Answer

Meiotic non-disjunction

Answer

Uniparental disomy

Answer

Genomic imprinting

Answer

Partial deletion

Answer

Trinucleotide repeat

Question 2

A 10-year-old boy comes for a post-operative clinic visit with his ENT surgeon three months after airway reconstruction surgery and placement of a tracheostomy tube. Since the surgery, he says that he has been able to breathe better and is now getting used to tracheostomy care and tracheostomy tube changes. In addition to this surgery, he has had over twenty surgeries to implant hearing aids, reconstruct his cheekbones, and support his jaw to enable him to swallow. He was born with these abnormalities and had difficult breathing, hearing, and eating throughout his childhood. Fortunately, he is now beginning to feel better and is able to attend public school where he is one of the best students in the class. Abnormal development of which of the following structures is most likely responsible for this patient's malformations?

Accepted Answer

First branchial arch

Answer

Second branchial cleft

Answer

First branchial pouch

Answer

Third and fourth branchial pouches

Answer

Second branchial arch

Question 3

A child is born by routine delivery and quickly develops respiratory distress. He is noted to have epicanthal folds, low-set ears that are pressed against his head, widely set eyes, a broad, flat nose, clubbed feet, and a receding chin. The mother had one prenatal visit, at which time the routine ultrasound revealed an amniotic fluid index of 3 cm. What is the most likely underlying cause of this patient's condition?

Accepted Answer

Bilateral renal agenesis

Answer

Unilateral renal agenesis

Answer

An extra 18th chromosome

Answer

Autosomal recessive polycystic kidney disease (ARPKD)

Answer

A microdeletion in chromosome 22

Question 4

A 5-year-old boy is brought to the emergency department by his grandmother because of difficulty breathing. Over the past two hours, the grandmother has noticed his voice getting progressively hoarser and occasionally muffled, with persistent drooling. He has not had a cough. The child recently immigrated from Africa, and the grandmother is unsure if his immunizations are up-to-date. He appears uncomfortable and is sitting up and leaning forward with his chin hyperextended. His temperature is 39.5°C (103.1°F), pulse is 110/min, and blood pressure is 90/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 95%. Pulmonary examination shows inspiratory stridor and scattered rhonchi throughout both lung fields, along with poor air movement. Which of the following is the most appropriate next step in management?

Accepted Answer

Prepare for emergency airway management in the operating room with anesthesia and ENT backup

Answer

Nebulized albuterol

Answer

Direct laryngoscopy and pharyngoscopy

Answer

Immediate nasotracheal intubation in the emergency department

Answer

Intravenous administration of antibiotics

Question 5

A 6-year-old boy is brought in for evaluation by his adopted mother due to trouble starting 1st grade. His teacher has reported that he has been having trouble focusing on tasks and has been acting out while in class. His family history is unknown as he was adopted 2 years ago. His temperature is 36.2°C (97.2°F), pulse is 80/min, respirations are 20/min, and blood pressure 110/70 mm Hg. Visual inspection of the boy's face shows a low set nasal bridge, a smooth philtrum, and small lower jaw. Which of the following findings would also likely be found on physical exam?

Accepted Answer

Holosystolic murmur

Answer

Cataracts

Answer

Congenital deafness

Answer

Limb hypoplasia

Answer

Wide notched teeth

Question 6

A 4-year-old boy is brought to the physician because of non-fluent speech. His mother worries that his vocabulary is limited for his age and because he cannot use simple sentences to communicate. She says he enjoys playing with his peers and parents, but he has always lagged behind in his speaking and communication. His speech is frequently not understood by strangers. He physically appears normal. His height and weight are within the normal range for his age. He responds to his name, makes eye contact, and enjoys the company of his mother. Which of the following is the most appropriate next step in management?

Accepted Answer

Audiology testing

Answer

Referral to speech therapist

Answer

Evaluate response to methylphenidate

Answer

Psychiatric evaluation

Answer

Thyroid-stimulating hormone

Question 7

An epidemiologist is evaluating the efficacy of Noxbinle in preventing HCC deaths at the population level. A clinical trial shows that over 5 years, the mortality rate from HCC was 25% in the control group and 15% in patients treated with Noxbinle 100 mg daily. Based on this data, how many patients need to be treated with Noxbinle 100 mg to prevent, on average, one death from HCC?

Accepted Answer

10

Answer

20

Answer

73

Answer

50

Answer

100

Question 8

A 23-year-old man comes to the physician for evaluation of decreased hearing, dizziness, and ringing in his right ear for the past 6 months. Physical examination shows multiple soft, yellow plaques and papules on his arms, chest, and back. There is sensorineural hearing loss and weakness of facial muscles bilaterally. His gait is unsteady. An MRI of the brain shows a 3-cm mass near the right internal auditory meatus and a 2-cm mass at the left cerebellopontine angle. The abnormal cells in these masses are most likely derived from which of the following embryological structures?

Accepted Answer

Neural crest

Answer

Surface ectoderm

Answer

Neural tube

Answer

Notochord

Answer

Mesoderm

Question 9

A 52-year-old woman sees you in your office with a complaint of new-onset headaches over the past few weeks. On exam, you find a 2 x 2 cm dark, irregularly shaped, pigmented lesion on her back. She is concerned because her father recently passed away from skin cancer. What tissue type most directly gives rise to the lesion this patient is experiencing?

Accepted Answer

Neural crest cells

Answer

Endoderm

Answer

Mesoderm

Answer

Ectoderm

Answer

Neuroectoderm

Question 10

A 29-year-old man presents to the emergency room with facial weakness. He first noticed that he was having trouble smiling normally while at dinner with friends the night before. He also noticed that his food had less taste than usual during the dinner. He woke up on the day of presentation with a complete inability to move the right side of his face. He recently returned from an extended camping trip in the Appalachian Mountains, but he did not find any tick bites following the camping trip. His past medical history is notable for Achilles tendonitis and carpal tunnel syndrome. He works as a computer programmer. He smokes marijuana occasionally but does not smoke cigarettes. His temperature is 98.6°F (37°C), blood pressure is 120/75 mmHg, pulse is 80/min, and respirations are 18/min. On exam, he is well-appearing in no acute distress. There is loss of facial wrinkles along the forehead, eyelids, and nasolabial folds. He is unable to completely close his right eye, raise his eyebrows, or smile with the right side of his mouth. Sensation is intact to light touch along the forehead, maxilla, and mandible bilaterally. Where is the most likely source of this patient’s lesion?

Accepted Answer

Stylomastoid foramen

Answer

Superior orbital fissure

Answer

Petrotympanic fissure

Answer

Inferior orbital fissure

Answer

Dorsal frontal lobe

Pharyngeal arches

Study Resources

Lessons

Questions

Flashcards

Lessons

First pharyngeal arch derivatives

Second pharyngeal arch derivatives

Third pharyngeal arch derivatives

Fourth and sixth pharyngeal arch derivatives

Pharyngeal pouches

Pharyngeal clefts

Pharyngeal membrane derivatives

Neural crest contribution to pharyngeal arches

Congenital anomalies of pharyngeal arch derivatives

Clinical correlations of pharyngeal development

Practice Questions

Flashcards

About Pharyngeal arches for USMLE

Lessons in Pharyngeal arches

Master Pharyngeal arches