Autism and 'T-Rex Arms'

In this blog post, we will look into the association of Autism Spectrum Disorder and “T-Rex arms”. We will explore what the term “T-Rex arms” means, then continue with what autism is by considering this neurodevelopmental disorder through prevalence, genetics, and symptoms. Finally, we will explore whether there is scientific evidence suggesting that 'T-Rex arms' are in fact present in autism.
Frederika Malichová

Frederika Malichová

Neuroscientist at the University Of Cambridge.

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Autism and T-Rex Arms

Although there is no scientific evidence correlating T-Rex arms with autism, 'T-Rex arms' in autistic people are often observed, although physical characteristics are not typically associated with autism.

However, individuals with autism often exhibit differences in arm movements and motor impairments.

What Is Autism?

Autism, also known as Autism Spectrum Disorder, is a lifelong neurodevelopmental condition affecting the behavior of the affected individual.

We observe autism in a wide range of people regardless of their race, ethnicity, culture, or socioeconomic background, although it is more prevalent in boys than girls [3, 4].

An autistic person perceives the world in a different social and communicative context, resulting in differences in social and communication interactions [3, 4].

Often, people with autism may have difficulties talking to others, maintaining eye contact, and exhibit repetitive patterns of behavior [3, 4]. They often have very niche interests and seem to be in their “own world” [5]. However, the symptoms may vary as it is a spectrum disorder [6].

Autism includes conditions like Asperger syndrome, Rett syndrome, or typical autism [5].

It is believed that autism is strongly influenced by genetics but also environmental factors [7, 8].

What Are T-Rex Arms in Humans?

“T-Rex arms” are often used as a colloquial expression to refer to a condition observed in humans.

Essentially, when someone’s arms are perceived to be shorter than average, creating a disproportion between the limbs and the body, such as the one observed in the dinosaur Tyrannosaurus rex. In addition, the term “T-Rex arms” may also refer to bent arms in the shape of the arms of Tyrannosaurus rex.

Please note that this term does not relate to any evolutionary history of human arms and does not reflect the structure or function of the arms. In contrast, human arms have a greater range of movements and functions than T-Rex arms ever had.

The human arm’s structure and function are complex and encompass extensor and flexor muscles, bones, and assist us in the execution of a variety of actions, such as manipulation of objects or communication among people and animals [1, 2].

In conclusion, while the term "T-Rex arms" is often used in a colloquial context, it does not accurately reflect the complex structure, function, and evolutionary history of human arms.

Do People With Autism Also Suffer From T-Rex Arms?

Although there is not enough evidence to attribute 'T-Rex Arms' to autism, individuals affected by such disease may show signs of impaired motor control and movement.


Interestingly, “T-Rex arms” in the sense of bending your hand like the dinosaur Tyrannosaurus rex have been observed in autistic individuals. Such phenomenon is also called autistic arms.

However, it is not clinically recognized as a symptom of autism, although autistic arms or 'T-Rex arms' have been observed. That being said, it is just natural that more research needs to be done to fully understand the motor differences in autism and how the 'T-Rex arms' impact the lives of people with autism.

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Frederika Malichová

Frederika Malichová

Frederika is a postgraduate researcher at the University of Cambridge, where she investigates new biomarkers for Frontotemporal Dementia and other tauopathies. Her research has been published at prestigious conferences such as the Alzheimer’s Association International Conference 2023. She obtained her BSc in Biomedical Sciences from UCL, where she worked closely with the UK Dementia Research Institute.