WBR0884
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::A 4 year old boy is brought to the pediatrics clinic for his regular well baby check-up. The child seems to be developing well and has not missed any of his milestones so far. His physical exam was unremarkable except for a persistant soft spot on the child's skull suspicious for delayed closure of the fontanelles. Which of the following tissues share the same embryologic origin with the bones responsible for fontanelle closure?]] |
| Answer A | AnswerA::Arachnoid mater |
| Answer A Explanation | AnswerAExp::The arachnoid mater is derived from neural crest cells similar to the bones of the skull. |
| Answer B | AnswerB::Skeletal muscles |
| Answer B Explanation | AnswerBExp::Skeletal muscles are derived from mesoderm unlike the bones of the skull which are dervied from neural crest cells. |
| Answer C | AnswerC::Kidneys |
| Answer C Explanation | AnswerCExp::the kidneys are also derived from mesoderm. |
| Answer D | AnswerD::Retina |
| Answer D Explanation | AnswerDExp::The retina is derived from neuroectoderm. |
| Answer E | AnswerE::Anterior pituitary |
| Answer E Explanation | AnswerEExp::The anterior pituitary is derived from surface ectoderm. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The bones of the skull, unlike the rest of the skeletal system, are derived from neural crest cells. Other bones are generally derived from the mesodermal layer. Other derivatives of neural crest cells include:
Crane JF, Trainor PA. Neural crest stem and progenitor cells. Annu Rev Cell Dev Biol. 2006;22(1):267-86. Educational Objective: References: ]] |
| Approved | Approved::No |
| Keyword | WBRKeyword::Embryologic derviatives, WBRKeyword::neural crest cells, WBRKeyword::bones of the skull, WBRKeyword::arachnoid mater |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |