USMLE Embryology Questions
– Free Practice Qbank

A 29-year-old female presents with palpitations, increased sweating, and unintentional weight loss despite a good appetite. She also reports difficult swallowing and voice changes. All the symptoms have been developing over the past 6 months. The patient has no concurrent illnesses and takes no medications. Her vital signs are as follows: blood pressure 125/80 mm Hg, heart rate 106/min, respiratory rate 15/min, and temperature 37.0℃ (98.6℉). Physical examination is significant for increased perspiration, fine digital tremors, and a small mass at the posterior aspect of the tongue which moves along with the tongue movements. There is no neck swelling. Laboratory thyroid workup shows the following results:

A 99 mTc thyroid scan reveals hyperfunctional thyroid tissue at the base of the patient’s tongue. Which the following statements is correct?

1. This patient is at increased risk of thyroid carcinoma development
2. Most often in such condition, there is an additional thyroid tissue elsewhere in the neck
3. There is a male predilection for this condition
4. This is the rarest location for ectopic thyroid tissue
5. This condition results from a failure of caudal migration of thyroid tissue

1. Pronephros and celom
2. Mesonephros and celom
3. Pronephros and cloaca
4. Metanephros and celom
5. Mesonephros and cloaca

A 9-year-old boy presents with abdominal pain which started almost 6 hours ago. The pain is located in the periumbilical area and radiates to the right lower quadrant. There was no vomiting or stool passage since the pain onset. The patient reports that he passed stools with blood several times during the past month. The patient’s vital signs are as follows: blood pressure 110/70 mm Hg, heart rate 81/min, respiratory rate 16/min, and temperature 37.5℃ (99.5℉). Physical examination reveals abdominal tenderness and guarding in the periumbilical area. Abdominal ultrasound does not reveal any abnormality with appendix. The patient is taken for exploratory laparoscopy. On laparoscopy, a 2-cm wide inflamed diverticulum is found 40 cm proximally to the ileocecal valve. It is resected and sent for histological evaluation. The result is shown in the exhibit. Which of the following statements is true? 

1. Most probably, it resulted from traction by embryonic peritoneal adhesions
2. The most probable cause of this diverticulum is increased intraluminal pressure
3. It is an unobliterated embryonic bile duct
4. It is a remnant of embryonic omphalomesenteric duct
5. It is a false diverticulum

1. Release of a polar body
2. Degeneration of the sperm tail
3. Acrosomal reaction
4. The second meiotic division
5. Formation of the spindle apparatus

A healthy 37-year-old woman (gravida 3, para 1) who undergone in-vitro fertilization delivers vaginally a boy. On examination, he is found to have his urethral meatus opening placed on the ventral side of the penis just under its head. Which statement about the patient’s condition is correct?

1. Younger age of the mother is a major risk factor for this condition.
2. It results from failure of genital swellings fuse.
3. Hypospadias repair before the age of 3 years is associated with increased incidence of urethrocutaneous fistula.
4. Such anatomy is formed before the 12th week of intrauterine development.
5. It results from failure of genital folds fuse.

1. This condition is associated with teenage mothers
2. 95% of these patients die in the 1st year of life
3. The condition is more common in males
4. Thrombocytopenia is the least common hematological abnormality found in these patients
5. The most common congenital heart disease seen in this condition is patent ductus arteriosus

1. Vermiform appendix
2. Anal membrane
3. Fibrous cord remnant
4. Vitelline duct
5. Cloaca

1. Patent processus vaginalis
2. Engorgement of the pampiniform plexus
3. Collection of fluid in the tunica vaginalis
4. Infection of the epididymis
5. Neoplasm of the testicle

1. On puncture of this structure, blood is the most likely content to be obtained
2. It is most likely a result of viral replication within testicular tissue
3. Revealed structure does not communicate with the peritoneal cavity
4. Impaired lymphatic drainage from the scrotum is the cause of the patient’s condition
5. A similar condition in girls could be caused by presence of the canal of Nuck