Influential Errors of Galen

In this article, we’ll be listing out other Influential Errors of Galen.

If you have been searching for the errors of Galen, look no further, because this article contains quite a number of influential errors of Galen.

Corpus Galenicum

Galen (129–199 AD) is a Greek physician. He is considered one of the fathers of anatomy and vivisection. Yet Galen’s human anatomy was often wrong because he never dissected humans, at least not to the public’s knowledge.

Galen Biography

Galen based his descriptions of human anatomy on dissections of animals such as sheep, oxen, pigs, dogs, and bears, and particularly the “Barbary ape,” an Old World monkey (Macaca sylvanus) that has a vestigial tail and thus superficially seems like an ape in this respect.

It was reported that tens of thousands of people died because of Galen’s erroneous theories.

Galen of Pergamon, the Greek physician whose anatomical findings went unchallenged for thirteen centuries until Andreas Vesalius’ revolutionary “On the Structure of the Human Body” in 1543.

Vesalius documented many errors of Galen, realizing that it was because Galen mostly did animal dissections. Galen held such sway over medical thinking that Vesalius faced viscous attacks for daring to question him.

This curious illustration in Vesalius’ textbook titled “a human skull resting on a dog skull” seems to be a visual snipe at Galen, but is also thought to be an early attempt at comparative anatomy.

Galen Errors

  • Galen did not describe the two most peculiar muscles of the human forelimb, the flexor pollicis longus and extensor pollicis brevis, as distinct muscles.
  • Apart from such accurate descriptions of macaques that are inaccurate for humans, he inaccurately described features that are similar in humans and macaques, contributing to further errors about human anatomy.
  • Galen did not recognize the extensor carpi radialis brevis and longus as separate muscles.
  • Galen stated that air enters the heart directly from the lungs and that blood passes from one side of the heart to the other through the septum between these ventricles.
  • There is no blood clot during the formation of a fetus.
  • The human breast bone is made up of seven segments.
  • Galen claimed that the humerus (the upper arm bone) was the longest bone in the body.
  • Galen claimed that the lower jaw was made up of two bones, not one.
  • That the blood goes back and forth from the heart in an ebb-and-flow motion.
  • Galen did not describe the two most peculiar muscles of the human forelimb, the flexor pollicis longus and extensor pollicis brevis, as distinct muscles.
  • Galen claimed that the brain, spinal cord, and ventricles comprise a single structure.
  • Galen claimed that the stomach has two layers and the coccyx includes five bones.
  • The blood moves back and forth between the liver and the kidney.
  • Galen, stated that the human lower jaw is made up from two bones joined together in the middle line
  • Veins originally originate from the liver.
  • Galen described the tracheal semicircular cartilages as “rough arteries” and named each of them “arteria tracheia,” which convey air (pneuma) to the smooth arteries (pulmonary veins) that come from the heart and the presence of a pulse in them.
  • The heart has three cavities.
  • The liver has five lobes.
  • The wall of the urinary bladder has one thick layer and a round muscle around its neck.
  • The optic nerve meets without decussating.
  • The ureters run obliquely for some distance in the bladder wall before opening into its cavity, and there is a membrane that acts like a lid, covering the end of the ureters and preventing the backflow of the urine.
  • Galen stated that the uterus has two cavities with a single end.
  • Galen described a single tube for urine and semen in the penis.
  • Galen thought that the venous blood flows within the heart, and that the heart has three ventricles and was strengthened by a special bone
  • He correctly recognized that blood passes from the right to the left side of the heart, but decided this was accomplished through tiny pores in the septum rather than through the pumping action of the heart.
  • He claimed that blood formed in the liver and was circulated from there throughout the body in the veins.
  • He claimed that the brain generated and transmitted another vital spirit through the nerves to the muscles, which allow movement and sensation.

Article Title: Influential Errors of Galen

Typed by: Students Mirror Educators


  • https://www.bbc.co.uk/bitesize/guides/zyscng8/revision/3
  • https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.23523

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