The coronal line is a landmark in human anatomy, an imaginary line running across the top of the head from one side to the other. Medical professionals use this line as a reference point for describing the location of various anatomical structures. This line’s importance extends from early human development to advanced medical diagnostics.
Defining the Coronal Line and Plane
The coronal line’s location is visualized as the path a headband would take, running from ear to ear across the top of the skull. Anatomically, it marks the junction between the frontal bone at the front of the head and the two parietal bones that form the sides and top of the skull. This junction is a physical joint, and understanding related terminology is helpful.
Three related terms are associated with this anatomical region. The coronal suture is the dense, fibrous connective tissue that joins the frontal and parietal bones. The coronal plane, also known as the frontal plane, is an imaginary vertical plane that divides the entire body into front (anterior) and back (posterior) sections. This plane is perpendicular to the sagittal plane, which divides the body into left and right halves.
The Coronal Suture in Infant Development
In newborns and infants, the coronal suture plays an important role in development. At birth, the cranial sutures, including the coronal, are flexible fibrous bands of tissue. This flexibility allows the bony plates of the skull to overlap during childbirth, enabling the baby’s head to pass through the birth canal.
Following birth, these flexible sutures accommodate the rapid growth of the brain during the first few years of life. The meeting point of the coronal suture with other sutures forms the fontanelles, or “soft spots,” on an infant’s head. The anterior fontanelle, the largest of these, is found where the coronal and sagittal sutures intersect. This fontanelle typically remains open until a child is between 7 and 19 months old.
Importance in Medical Imaging
The concept of the coronal plane is important to modern medical imaging. Technologies like magnetic resonance imaging (MRI) and computed tomography (CT) scans produce images in “coronal views.” A coronal view presents a two-dimensional image of the body as if it were sliced from front to back. This perspective helps medical professionals diagnose and treat a wide range of conditions.
Visualizing the body in coronal slices allows doctors to examine the spatial relationships between internal structures. For example, a coronal MRI of the brain can help identify tumors or evidence of a stroke. Similarly, a coronal CT scan is often used to evaluate the sinuses or plan for orthopedic surgeries. This front-to-back perspective provides clear views of structures that might be difficult to see in other imaging planes.
Coronal Craniosynostosis
Coronal craniosynostosis is a medical condition that arises when one or both of the coronal sutures fuse prematurely. This early closure restricts the normal growth of the skull, leading to characteristic changes in head shape. If the fusion occurs on only one side (unicoronal), it can cause the forehead on the affected side to appear flattened, a condition known as anterior plagiocephaly.
When a suture closes too early, the skull cannot expand properly to accommodate the growing brain, which can sometimes lead to increased pressure inside the skull. The most apparent sign of the condition is an abnormally shaped head, noticeable at birth or within the first few months of life. Treatment for coronal craniosynostosis typically involves surgery to correct the shape of the head and relieve any pressure on the brain. This intervention is often performed before a child is one year old.