AIIMS November 2011 – MCQ 65

Which of the following is true regarding appearance of ossification centers?
A. First appears at end of 2nd month
B. First appears at start of 3rd month
C. First appears at end of 3rd month
D. First appears at end of 4th month

Correct answer : A. First appears at end of 2nd month

Ref: Gray’s Anatomy, 39th p818
The clavicle begins to ossify before any other bone in the body, and is ossified from three centers. The shaft of the bone is ossified in condensed mesenchyme from two primary centres, medial and lateral, which appear between the fifth and sixth weeks of intrauterine life, and fuse about the forty-fifth day.