Tag: cranium

Categories : General Interest Skeletal SystemTags :

Why Breakdancing can Give You a Cone-shaped Head

On By ModernMedia
Photo by Zac Ong on Unsplash

Adam Taylor, Lancaster University

For those of a certain age, Coneheads is an iconic 90s film. But for breakdancers, it seems, developing a cone-shaped head can be an occupational hazard.

According to a 2024 medical case report, a breakdancer who’d been performing for 19 years was treated for “headspin hole”, a condition also known as “breakdancer bulge” that’s unique to breakdancers. It entails a cone shaped mass developing on top of the scalp after repetitive head-spinning. Additional symptoms can include hair loss and sometimes pain around the lump.

Approximately 30% of breakdancers report hair loss and inflammation of their scalp from head-spinning. A headspin hole is caused by the body trying to protect itself. The repeated trauma from head-spinning causes the epicranial aponeurosis – a layer of connective tissue similar to a tendon, running from the back of your head to the front – to thicken along with the layer of fat under the skin on top of the head in an attempt to protect the bones of skull from injury.

The body causes a similar protective reaction to friction on the hands and feet, where callouses form to spread the pressure and protect the underlying tissues from damage. Everyday repetitive activities from holding smartphones or heavy weights through to poorly fitting shoes can result in callouses.

But a cone-shaped head isn’t the only injury to which breakdancers are prone, however. Common issues can include wrist, knee, hip, ankle, foot and elbow injuries, and moves such as the “windmill” and the “backspin” can cause bursitis – inflammation of the fluid filled sacs that protect the vertebrae of the spine. A headspin hole isn’t the worst injury you could sustain from breakdancing either. One dancer broke their neck but thankfully they were lucky enough not to have any major complications.

Others, such as Ukrainian breakdancer Anna Ponomarenko, have experienced pinched nerves that have left them paralysed. Ponomarenko recovered to represent her country in the Paris 2024 Olympics.

As with other sports, it’s unsurprising to hear that the use of protective equipment results in the reduction of injuries in breakdancing too.

But breakdancers aren’t the only ones to develop cone shaped heads.

Newborns

Some babies are born with a conical head after their pliable skull has been squeezed and squashed during the journey through the vaginal canal and the muscular contractions of mother’s uterus.

A misshapen head can also be caused by caput secundum, where fluid collects under the skin, above the skull bones. Usually, this condition resolves itself within a few days. Babies who’ve been delivered using a vacuum assisted cup (known as a Ventouse) – where the cup is applied to the top of the baby’s head to pull them out – can develop a similar fluid lump called a chignon.

Vacuum assisted delivery can also result in a more significant lump and bruising called a cephalohematoma, where blood vessels in the bones of the skull rupture. This is twice as common in boys than in girls and resolves within two weeks to six months.

If you’ve ever seen newborns wearing tiny hats in the first few hours of their life, then one of these conditions may be the reason.

Some children may also present with “cone-head” due to craniosynostosis, which occurs in about one in every 2000-2500 live births.

Newborn skulls are made up of lots of small bony plates that aren’t fused together, which enables babies’ brains to grow without restriction. Usually, once the brain reaches a slower growth pace that the bones can keep up with, the plates fuse together. In craniosynostosis, the plates fuse together too early creating differently shaped heads. Surgery can prevent brain growth restriction but is usually unnecessary if the child hasn’t been identified as having an shaped head by six months of age.

Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Categories : Neurology Skeletal SystemTags :

A Single Gene Variant that Gave Rise to Humans’ Unique Skull Base

On By ModernMedia
Source: CC0

One of the unique features that Homo sapiens have compared with other closely related hominin species and primates is the shape of the base of the skull, which enabled larger brains to evolve. Now, in a study recently published in the American Journal of Human Genetics, a team from Tokyo Medical and Dental University (TMDU), the University of Helsinki, and the University of Barcelona has analysed a genomic variant responsible for this unique human skull base morphology.

Most of the genomic changes that occurred during human evolution did not occur directly to genes themselves, but in regions responsible for controlling and regulating the expression of genes. Variants in these same regions are often involved in genetic conditions, causing aberrant gene expression throughout development. Identifying and characterising such genomic changes is therefore crucial for understanding human development and disease.

The development of the basicranial region, the base of the skull where it joins the vertebra, was key in the evolution of Homo sapiens, as we developed a highly flexed skull base that allowed our increased brain size. Therefore, variants that affect the development of this region are likely to have been highly significant in our evolution.

First, the team searched for variants in just a single letter of the DNA code, called single nucleotide polymorphisms (SNPs), that caused different regulation of genes in the basicranial region in Homo sapiens compared with other extinct hominins. One of these SNPs stood out, located in a gene called TBX1.

They then used cell lines to show that the SNP, called “rs41298798,” is located in a region that regulates the expression levels of the TBX1 gene, and that the “ancestral” form of the SNP, found in extinct hominins, is associated with lower TBX1 expression, while the form found in Homo sapiens gives us higher levels of TBX1.

“We then employed a mouse model with lower TBX1 expression,” explains lead author Noriko Funato, “which resulted in distinct alterations to the morphology at the base of the skull and premature hardening of a cartilage joint where the bones fuse together, restricting the growth ability of the skull.” The changes in the Tbx1-knockout mice were reminiscent of the known basicranial morphology of Neanderthals.

These morphological changes are also reflected in human genetic conditions associated with lower TBX1 gene dosage, such as DiGeorge syndrome and velocardiofacial syndrome, further indicating the significance of this genetic variant in the evolution of our unique skull base morphology.

The identification of this genomic variant sheds light on human evolution, as well as providing insight into common genetic conditions associated with lower expression of the TBX1 gene, paving the way for greater understanding and management of these conditions.

Source: Tokyo Medical and Dental University