The clavicle is unique among long bones because its ossification is predominantly:
- A Intramembranous, being the first bone to ossify in the embryo ✓
- B Endochondral, with a cartilaginous precursor forming at 5 weeks gestation
- C Entirely intramembranous without any secondary cartilaginous centers
- D Periosteal appositional ossification only
Correct answer: A. Intramembranous, being the first bone to ossify in the embryo
Explanation
The clavicle is the first bone to ossify in the human embryo (5th–6th week of intrauterine life) and its shaft ossifies primarily by intramembranous ossification (from two primary centers — sometimes fusing). However, the sternal end of the clavicle does have a secondary epiphyseal center that ossifies endochondrally; this center is the LAST to fuse (at 25–31 years), making it one of the latest fusing epiphyses in the body and valuable in forensic age estimation. The clavicle is therefore unique in being both the first to begin ossifying and among the last to complete ossification.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.