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USMLE/1
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Textbook
1. Anatomy
1.1 Immune system, blood and lymphoreticular system
1.2 Nervous system and special senses
1.3 Skin and subcutaneous tissue
1.4 Musculoskeletal system
1.5 Anatomy of the cardiovascular system
1.6 Respiratory system
1.7 Respiratory system additional information
1.8 Renal and urinary system
1.9 Renal system additional information
1.10 Gastrointestinal system
1.11 Gastrointestinal system additional information
1.12 Duodenum
1.13 Liver
1.14 Female reproductive system and breast
1.15 Female reproductive system additional information
1.16 Fallopian tubes
1.17 Male reproductive system
1.18 Male reproductive system additional information
1.19 Prostate
1.20 Endocrine system
1.21 Embryology
1.21.1 Gastrointestinal system
1.21.2 Gastrointestinal developmental disorders
1.21.3 Genitourinary system
1.21.4 Nervous system
1.21.5 Respiratory and cardiovascular systems
1.21.6 Pharyngeal arches
1.21.7 Placenta
1.21.8 Umbilical cord and fetal circulation
1.21.9 Additional information
1.22 Additional information
2. Microbiology
3. Physiology
4. Pathology
5. Pharmacology
6. Immunology
7. Biochemistry
8. Cell and molecular biology
9. Biostatistics and epidemiology
10. Genetics
11. Behavioral science
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1.21.9 Additional information
Achievable USMLE/1
1. Anatomy
1.21. Embryology

Additional information

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  1. Box for secondary retroperitoneal organs: These organs were intraperitoneal during early development. Later on their mesenteries were pushed back against the posterior abdominal wall so that they became retroperitoneal. These organs are the pancreas, duodenum, ascending and descending colon.

  2. Embryonic remnants

Embryonic Origin Remnant
Foramen ovale Fossa ovalis
Ductus arteriosus Ligamentum arteriosum
Ductus venosus Ligamentum venosum
Umbilical vein Ligamentum teres hepatis
Umbilical arteries MediaL umbilical ligament, part of internal iliac and superior vesical arteries.
Mesonephric or Wolffian ducts In males it becomes efferent duct including the epididymis, vas deferens and seminal vesicles. In females, it remains as epoophoron and paroophoron, Gartner’s ducts.
Paramesonephric or Mullerian ducts In females, it becomes the fallopian tubes, uterus, cervix, upper part of vagina. In males remnants seen in the prostatic utricle.
Urachus or allantoic stalk MediaN umbilical ligament
Notochord Nucleus pulposus
  1. Meconium ileus: It is caused due to thick, desiccated meconium obstructing the ileum. It is seen in newborns with cystic fibrosis. Meconium ileus presents with bilious vomiting, abdominal distension with a high risk of perforation and peritonitis. Prenatal ultrasound shows hyperechoic masses from thick meconium, dilated bowel loops and non-visualization of the gallbladder. Imaging postnatally shows dilated bowel loops with or without (more common due to dry meconium) air-fluid levels, “soap bubble” or mottled appearance and in some cases, abdominal calcifications. Distal colon will show microcolon appearance due to disuse.
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