General anatomy: bone development: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · General anatomy: bone development

Sample item

A histologist examines a 12-week fetal femur. There is a thin collar of bone around the mid-shaft, with calcified cartilage and invading blood vessels in the centre. Which description fits this section?

AEndochondral ossification beginning at both epiphyses before the shaftBEndochondral ossification beginning at the primary centre in the diaphysisCAppositional bone growth from the periosteum without a cartilage modelDIntramembranous ossification beginning at a secondary centre in the epiphysis

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Endochondral ossification beginning at the primary centre in the diaphysis

Long bones form by endochondral ossification on a hyaline cartilage model. A periosteal bone collar forms around the diaphysis, the cartilage inside calcifies and is invaded by vessels, and this primary centre appears at about 7 to 8 weeks. Secondary centres in the epiphyses appear later.

Option by option

A. Endochondral ossification beginning at both epiphyses before the shaft
Epiphyseal secondary centres appear after birth or late in gestation, long after the shaft starts.
B. Endochondral ossification beginning at the primary centre in the diaphysis (correct)
Correct. The primary centre and bone collar in the diaphysis start long bone formation.
C. Appositional bone growth from the periosteum without a cartilage model
A cartilage model is the basis of long bones; membrane bone forms flat skull bones and the clavicle.
D. Intramembranous ossification beginning at a secondary centre in the epiphysis
Long bones are not formed in membrane, and secondary centres appear after the primary centre.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is B, Endochondral ossification beginning at the primary centre in the diaphysis. Long bones form by endochondral ossification on a hyaline cartilage model.

Why is "Endochondral ossification beginning at both epiphyses before the shaft" not the answer?

Epiphyseal secondary centres appear after birth or late in gestation, long after the shaft starts.

Why is "Appositional bone growth from the periosteum without a cartilage model" not the answer?

A cartilage model is the basis of long bones; membrane bone forms flat skull bones and the clavicle.

Why is "Intramembranous ossification beginning at a secondary centre in the e…" not the answer?

Long bones are not formed in membrane, and secondary centres appear after the primary centre.

What concept does this question test?

It tests General anatomy: bone development in Anatomy. A periosteal bone collar forms around the diaphysis, the cartilage inside calcifies and is invaded by vessels, and this primary centre appears at about 7 to 8 weeks. Secondary centres in the epiphyses appear later.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study General anatomy: bone development?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.