In medicine, macrocephaly refers to having a head that is too large. In macrocephaly there is a build-up of fluid in the brain and the brain is disproportionately large and heavily developed. This may be due to a medical cause, such as hydrocephalus. To ensure proper fluid production in our brains, a properly functioning ventricular system is very important. A developmental disorder can also be the cause of a large head, such as autism. The man with the biggest head is André ‘The Giant’ Roussimoff. A French wrestler from Paris.
Macrocephaly
The word macrocephaly comes from Ancient Greek, where ‘makros’ (macro) and ‘kephale’ (cephaly) mean ‘large’ and ‘head’ respectively. Macrocephaly is attributed to someone when the skull circumference is greater than two times the standard deviation above the average head circumference of the same sex and age. The statistic states that the average head circumference plus 2 times the standard deviation should include no less than 98 percent of the head circumferences. If someone falls outside this category, they can speak of macrocephaly.
Hydrocephalus or hydrocephalus
Hydrocephalus, also called ‘hydrocephalus’, is caused by a disturbance in the circulation of the spinal and cerebrospinal fluid. There is an excess amount of cerebrospinal fluid present that exerts pressure on the brain. This can result in the brain and its associated functions being affected. Although hydrocephalus is mainly known in children and at birth, it is also possible for an adult person to have this condition.
Obstructive hydrocephalus
In obstructive hydrocephalus, a blockage within the ventricular system causes distention of the ventricular system. This usually happens at the aqueduct, because this is the finest canal. Increased pressure and widening of the ventricles are then inevitable. Adhesions in the brain or tumors are known causes of this. With reduced absorption of fluid in the platelets (also called communicating hydrocephalus), the blood flow is not disturbed, but the cause is bleeding and infections. These can cause increased pressure within the skull. I
In approximately 60 percent of cases, the cause of macrocephaly can be attributed to hydrocephalus, often due to disturbed circulation of the cerebral and spinal fluid. In rare cases, an excess of cerebrospinal fluid is caused by a tumor or cancer. In infants, hydrocephalus is sometimes caused by spina bifida.
Fluid production in the brain
In our skull, our brains are surrounded by fluid. Specifically, this is called cerebrospinal fluid. This fluid is produced in the brain chambers or ventricles via the venous plexus (chorioides) and has 3 important functions, namely:
- protection of the brain, in particular against pressure, shock and toxic substances
- nutrition of the brain cells
- stimulation of the electrical conduction of nerve signals
The ventricular system
The ventricular system is made up of two side ventricles, a third and a fourth ventricle. Between the third and fourth ventricles there is an important channel, called an ‘aqueduct’, through which the cerebrospinal fluid can reach the fourth ventricle. The ventricles are responsible for the production of cerebrospinal fluid. There is approximately 150 ml of fluid in the skull, which is replaced approximately three times a day. Most of the cerebrospinal fluid is produced in the lateral ventricles. From these two ventricles, fluid flows together through two openings, also called the foramina of Monro, and can thus reach the third ventricle. Finally, the thin channel that leaves the third ventricle (the aqueduct) allows the cerebrospinal fluid to flow to the fourth ventricle.
Cerebrospinal fluid escapes
In addition, the cerebrospinal fluid can also escape from the fourth ventricle in three different ways, namely via one in the midline and two on either side. This also allows it to easily reach the space along the brain. Ultimately, the fluid flows partly to the spinal canal that surrounds the spinal cord and also to the brain where it is absorbed into blood vessels.
Big head in autism
A connection has also been found that a developmental disorder can cause a large head, such as in people with autism.
André ‘The Giant’ Roussimoff: the man with the biggest head
André Roussimoff was born in Grenoble on May 19, 1946 and died in Paris at the age of 46. He was a world famous professional French wrestler. He suffered from acromegaly due to an enlargement of the pituitary gland in the brain. Acromegaly refers to the disproportionate growth of body parts. He became enormous in stature: +- 2.20 meters and weighed around 240 kilograms at his heaviest moment.
