In cranial synostosis scaphyocephaly there is premature closure of which suture ?
**Core Concept**
Cranial synostosis scaphyocephaly is a condition characterized by premature closure of one or more cranial sutures, leading to an abnormal head shape. The sagittal suture is the most common site of premature closure, resulting in scaphyocephaly, a condition where the head becomes elongated and narrow.
**Why the Correct Answer is Right**
The sagittal suture is the midline suture that runs along the top of the skull, separating the two parietal bones. Premature closure of this suture leads to an abnormal growth pattern, causing the head to become elongated. This is due to the increased pressure exerted on the surrounding bones, which are forced to grow more rapidly to compensate for the restricted growth in the sagittal plane.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the coronal suture, which runs along the sides of the skull, is more commonly associated with brachycephaly, a condition characterized by a short, broad head shape.
* **Option B:** This option is incorrect because the lambdoid suture, which runs along the back of the skull, is not typically associated with scaphyocephaly.
* **Option C:** This option is incorrect because the metopic suture, which runs along the top of the forehead, is a separate entity that can close prematurely, leading to a condition known as trigonocephaly.
**Clinical Pearl / High-Yield Fact**
Remember that premature closure of the sagittal suture is the most common cause of scaphyocephaly, and it often presents with an elongated head shape and a narrow forehead.
**Correct Answer:** C. Sagittal suture.