Yorkshire men straight to the point, or not? Validation of the John Thomas Sign
The subtleties of radiological fracture diagnosis are qualities of
Orthopaedic surgeons, not always appreciated by other specialties. They
often rely on understated radiological clues to aid diagnosis, including
soft tissue shadows. Interest has been raised regarding the usefulness of
phallic shadows on pelvic x-rays, as an aid to fracture diagnosis. The
‘John Thomas Sign’ (inclination of the penis towards the hip or pelvic
fracture) has been thrust, from the intellectual banter of trauma
meetings, into the spotlight by an article from New Zealand advocating its
use1. The group found a positive sign in 70% (n=91/130) of hip fracture
patients. However, the validity of this finding has not been tested for
the northern hemisphere, in particular Yorkshire. We investigated whether
the John Thomas (JT) sign was upstanding to scrutiny or a mere flop in
60 randomly selected x-rays from male patients with proximal femoral
fractures were reviewed independently by two researchers. Mean age was
78.2 years, 33 left and 27 right fractures. JT was positive in 37%
(n=22/60), negative (declined from the fracture) in 20% (n=12/60) and
equivocal (midline) in 43% (n=26/60). Distressingly, the JT positive
predictive value was only 47.8%, sensitivity 45.8%, and specificity 64.7%.
There was no correlation (p=0.84) between the JT and time of the year or
severity of fracture (p=0.34).
The authors do not wish to go ‘head to head’ with the New Zealand group,
but their findings could not be applied to the gentlemen of Yorkshire
where the JT sign has little diagnostic or prognostic value. Environmental
factors have been implicated in the genital asymmetry, included
handedness2, however, we believe that geographical and social differences
are responsible for the variation in results. Yorkshire men are renowned
for their directness; however, being British gentleman, modesty and even-
handedness are amongst their finer qualities. The outgoing antipodeans are
often over exuberant about there successes and it may be this subconscious
trait which overrides higher cerebral function.
It has long been recognised by tailors that gentleman often prefer to
‘dress’ to a side (more commonly left), and have traditionally made the
legs of the trousers on the preferred side slightly more capacious.
Cyclists have realised the advantage of a skewed saddle position3,
allowing increased time in the saddle by reducing external pressure.
Victorian fashionable gentlemen wore dressing rings, which controlled
penile bent, so as not to spoil the line of tight fitting trousers, with
Prince Albert being an exponent of this trend. Thus, it can be seen that
then, as now, British gentleman have shied away from drawing attention to
themselves. We feel that before routine screening of the JT sign is forced
upon us by higher bodies, further research into the efficacy and
reproducibility of this sign is warranted.
1. Thomas MC. Lyons BD. Walker RJ. John Thomas sign: common distraction or
useful pointer?. [Letter] Medical Journal of Australia. 169(11-12):670,
1998 Dec 7-21.
2. Chang RH, Hsu FK, Chan ST, et al. Scrotal asymmetry and handedness. J
Anat 1960; 94: 543-548.
3. ‘Rotating saddle nose slightly off center?’
Competing interests: No competing interests