Coronal suture completely fuses by the age of:

Actually Coronal suture completely fuses by 50-60 years, but the maximum age given in this question is 45 years and hence the answer. Age from Skull Sutures- Two halves of mandible unite at- 2 years. Metopic suture (2 halves of frontal bone) closes at: 3 years. Coronal, Sagittal, Lambdoid sutures sta to close on inner side at- 25 years. On outer side, fusion occurs in the following order- (1) Posterior 1/3rd sagittal suture- 30-40 yrs. (2) Anterior 1/3rd sagittal suture + lower 1/2 of coronal suture- 40-50 yrs. (3) Middle 1/3rd sagittal suture + upper 1/2 coronal suture- 50-60 yrs. Sutures on inner side close- 5-10 years earlier than outer side. For viewing X-rays, lateral view is preferable and the most successful estimation is done from sagittal suture, next lambdoid and then coronal. "Lapsed union" occurs commonly in sagittal suture (failure of ectrocranial suture closure.