About 15% of humans don't have a muscle in their forearms called the Palmaris Longus. As a muscle, it's pretty useless. But still, why do some people have it while others don't?
What mechanism is behind the whole thing? In this video, I explain why there's still variation among different bodies and why this obsolete muscle exists still.

☠NONE OF THE INFORMATION IN THIS VIDEO SHOULD BE USED AS MEDICAL ADVICE OR OPINION. IT IS FOR GENERAL EDUCATION AND ENTERTAINMENT☠

L I N K S
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Twitter:   / patkellyteaches  
Patreon:   / corporis  

O T H E R V I D E O S
⚰Medical History playlist:    • Playlist  
Anatomy Basics playlist:    • Basics of Anatomy  
Kinesiology and Biomechanics playlist:    • Musculoskeletal, Biomechanics, and K...  

S O U R C E S
Grip Strength Unaffected By PL Removal (2005)
http://journals.sagepub.com/doi/10.10...
Heredity of PL (2013)
http://jms.org.br/PDF/v30n4a08.pdf
Palmaris Longus comparison (2014)
https://www.hindawi.com/journals/bmri...
The changing upper extremity (2014)
https://www.ncbi.nlm.nih.gov/pmc/arti...
Percentages of PL (2016)
https://www.ncbi.nlm.nih.gov/pmc/arti...
https://www.flickr.com/photos/interne...
Lemur Hand By Alex Dunkel (Maky) Own work, CC BYSA 3.0, https://commons.wikimedia.org/w/index...
Chimpanzee By © Hans Hillewaert /, CC BYSA 3.0, https://commons.wikimedia.org/w/index...
https://en.wikipedia.org/wiki/Ringta...
https://en.wikipedia.org/wiki/Ringta...
   • Thompson's Test for Palmaris Longus (CR)  

A B O U T
Hi, I’m Patrick. I’m a freelance science writer based in the San Francisco Bay Area. I hold a bachelor’s degree in Athletic Training and a master’s in clinical exercise physiology. I used to work in the clinical setting as a certified athletic trainer, physical therapy aide, and a certified strength and conditioning specialist. After working in the clinical setting, I went back to school and became a teacher. The goal of my content is to help normal people, not just premed students, learn about the human body. That might mean explaining a topic from an anatomy class or exploring a topic from medical history.

C O N T A C T
If you’d like to sponsor a video or have other business inquiries:
patkellyteaches [at] gmail.com

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