Lower part of sternum fused by age
a) 12 years
b) 14 years
c) 18 years
d) 10 years
Answer: 14 years
Explanation:
In cartilaginous sternum, five double bony centres appear from above downwards during fifth, sixth, seventh, eighth and ninth fetal months.
The upper centre forms the manubrium.
Remaining four form body of sternum and fuse with one another from below to upwards.
Lower two centres fuse at age of 14 years and upper two centres fuse between 14 to 25 years.
The centre of xiphoid process appears during the third years or later and fuses with the body at about 40 years.