Skull fontanelles

Summary

Dr. Morton, a noted anatomist, discusses the skull and fontanelles in a fetal skull, explaining their structure and functions. He details the sutures and fontanelles, including the anterior, posterior, frontonasal, sphenoidal, and mastoid fontanelles, and their respective fusion times. He emphasizes the importance of fontanelles for skull flexibility during childbirth and brain growth, and touches on conditions like hydrocephalus and cranial dysplasia. The discussion also includes cultural practices like head binding and the work of actor Gaten Matarazzo, who has cranial dysplasia, in raising awareness and supporting those affected.

Takeaways

• 💡 The human skull is composed of various bones including the frontal, parietal, occipital, and temporal bones, which form the calvarium or skullcap.
• 🔍 Fontanelles are soft spots in the skull of a fetus or infant, which are areas where the fibrous connective tissue between the bones allows for flexibility and growth.
• 👶 The anterior fontanelle is the largest and diamond-shaped, located at the front of the skull, and it typically fuses around 18 months after birth.
• 🤕 The posterior fontanelle is smaller and triangular, located at the back of the head, and it usually fuses around three months after birth.
• 🧠 Fontanelles serve important functions such as allowing for the skull to mold during childbirth and accommodating rapid brain growth in early childhood.
• 🚫 If fontanelles do not fuse properly, conditions like Cleidocranial Dysplasia (CCD) can occur, which is characterized by open fontanelles and other developmental issues.
• 👨‍⚕️ Dr. Morton, a noted anatomist, explains that fontanelles can also indicate health status; for instance, a sunken fontanelle may suggest dehydration, while a bulging one could indicate increased intracranial pressure.
• 🌐 Cultural practices such as head binding have been known to influence the shape of the skull by applying pressure on the fontanelles during early development.
• 🧪 Hydrocephalus, a condition where there is an abnormal accumulation of cerebrospinal fluid, can cause the skull to enlarge as the fontanelles and sutures allow for this increase in size.
• 🌟 Actor Gaten Matarazzo from the TV show 'Stranger Things' is known to have CCD and has used his platform to raise awareness and support for individuals with the condition through the charity CCD Smiles.

Q & A

What is the frontal suture and when does it fuse?

The frontal suture is a line that divides the two frontal bones in a fetal skull, running through the midline. It fuses approximately two to three months after birth.

What are the parietal bones and what is their role in the skull?

The parietal bones form the superior wall of the calvarium, or skull. They are bordered by the coronal suture at the front and the sagittal suture down the middle.

What is the occipital bone and where is it located?

The occipital bone forms the back of the skull, the part that rests against a pillow. It is bordered anteriorly by the lambdoid suture.

What is the term 'calvaria' and what does it include?

Calvaria refers to the skullcap, which includes the frontal, parietal, and occipital bones that form the upper part of the skull.

What are fontanelles and how are they formed?

Fontanelles are soft spots in the skull where the fibrous connective tissue between the bones of the calvaria forms large spaces. They are areas where the bones have not yet fused.

How many fontanelles are there in the fetal calvaria and what are they?

There are six fontanelles in the fetal calvaria: the anterior fontanelle, the posterior fontanelle, and four smaller fontanelles known as the sphenoidal, mastoid, posterior auricular, and anterior auricular fontanelles.

What is the shape and approximate time of fusion for the anterior fontanelle?

The anterior fontanelle is diamond-shaped and is the last to fuse, around 18 months after birth.

What is the significance of the fontanelles in childbirth?

Fontanelles allow the skull to be more flexible during childbirth, enabling the molding of the skull as the baby passes through the birth canal.

How do fontanelles accommodate rapid brain growth in infants?

Fontanelles and sutures allow the skull to stretch and accommodate the rapid growth of the brain, especially during the first four years of life.

What is hydrocephalus and how does it affect the skull?

Hydrocephalus is a condition where there is an excessive accumulation of cerebrospinal fluid in the brain's ventricles, causing the ventricles to enlarge and the skull to become enlarged as well due to the fontanelles and sutures accommodating the increased pressure.

What is Cleidocranial Dysplasia (CCD) and how does it relate to fontanelles?

Cleidocranial Dysplasia (CCD) is a condition where the fontanelles and sutures do not fuse properly, leading to open sutures and other developmental issues. It is often associated with missing or underdeveloped clavicles.