Throckmorton sign (pelvis)

Last revised by Robert Foley on 20 Jul 2020

Throckmorton sign, also known as John Thomas sign, refers to when the penis points in the direction of unilateral disease, typically of the pelvis or hip. 

Throckmorton sign is a slang term used humorously by medical students and residents.

According to the first serious study of the sign published in 1988, the sign is less accurate than tossing a coin 2. This finding was supported by another subsequent study and also a meta-analysis 5,7.

History and etymology

It is named after Thomas "Tom" Bentley Throckmorton (1885-1961) 1,5, American neurologist and governor of the Iowa chapter of the American College of Physicians. He was not Governor of the State of Iowa, as is erroneously stated on several well-known websites!

In one specific Iranian institution it is known as Solooki sign, and this is only referenced in one paper, with a lack of evidence of it being used elsewhere 3.

Oram sign is also referred to in a single Scandinavian article, from Denmark, and is thought to derive from 'ormr', a word in Old Norse meaning serpent 4,5.

In France, Roy-Camille sign refers to the clinical finding in paraplegia that the penis assumes the laterality of the medullary lesion 5. It is named for Raymond Roy-Camille (1927-1994), a French orthopedic surgeon, famous for his advances in spinal surgery 6

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Cases and figures

  • Case 1: perfect example
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  • Case 2: pointing to AIIS avulsion
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  • Case 3: chronic osteomyelitis of left hip joint
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  • Case 4: left NOF fracture
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  • Case 5
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  • Case 6: false negative John Thomas sign
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