First pharyngeal arch derivatives — MCQs

A 54-year-old woman comes to the emergency department because of drooping on the left side of her face since that morning. She also reports difficulty closing her eyes and chewing. During the neurologic examination, the physician asks the patient to open her jaw against resistance. Which of the following muscles is most likely activated in this movement?

A 7-year-old boy is brought to the emergency department with a high fever and oxygen desaturation. He had a tracheostomy placed as an infant and has been placed on mechanical ventilation intermittently. Since then, he has had several bouts of pneumonia similar to his current presentation. In addition, he has been deaf since birth but is able to communicate through sign language. He attends school and performs above average for his grade. Physical exam reveals underdeveloped cheekbones, hypoplasia of the mandible, and malformed ears. Abnormal development of which of the following structures is most likely responsible for this patient's symptoms?

An otherwise healthy 45-year-old man comes to the physician because of a painful ulcer on his tongue for 3 days. Examination shows a shallow, tender 5-mm wide ulcer on the lateral aspect of the tongue, adjacent to his left first molar. There is no induration surrounding the ulcer or cervical lymphadenopathy. A lesion of the cranial nerve responsible for the transmission of pain from this ulcer would most likely result in which of the following?

A 27-year-old man comes to the physician because of a 1-day history of right-sided facial weakness and sound intolerance. Three days ago, he hit the right side of his head in a motor vehicle collision. He neither lost consciousness nor sought medical attention. Physical examination shows drooping of the mouth on the right side. Sensation over the face is not impaired. Impedance audiometry shows an absence of the acoustic reflex in the right ear. Which of the following muscles is most likely paralyzed in this patient?

A 45-year-old patient presents with difficulty speaking and swallowing following a stroke. MRI reveals an infarct in the medulla. Which of the following cranial nerve nuclei is most likely affected?

A group of investigators studying embryological defects in mice knock out a gene that is responsible for the development of the ventral wing of the third branchial pouch. A similar developmental anomaly in a human embryo is most likely to result in which of the following findings after birth?

A 2850-g (6-lb 5-oz) newborn is delivered at term to a 19-year-old primigravid woman via normal spontaneous vaginal delivery. The mother has had no prenatal care. Examination of the newborn in the delivery room shows malformed external ears, facial nerve palsy, and absence of the stapes bone on audiological testing. This patient's condition is most likely caused by abnormal development of the structure that also gives rise to which of the following?

A newborn male is evaluated in the hospital nursery two hours after birth. The patient was born at 39 weeks of gestation to a 30-year-old primigravid via vaginal delivery. The patient’s mother received routine prenatal care, and the pregnancy was uncomplicated. The patient’s anatomy ultrasound at 20 weeks of gestation was unremarkable. The patient’s mother denies any family history of genetic diseases. The patient’s Apgar scores were notable for poor muscle tone at both one and five minutes of life. The patient’s birth weight is 2.6 kg (5 lb 11 oz), which is at the 5th percentile. His height and head circumference are in the 15th and 3rd percentile, respectively. On physical exam, the patient has a wide nasal bridge, downslanting palpebral fissures, and widely spaced eyes. He has good respiratory effort with a high-pitched cry. This patient is most likely to have experienced a deletion on which of the following chromosomes?

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?

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?