It is important to evaluate lumbar ranges of motion when
assessing patients with suspected psoas major myofasciopathy,
particularly as active and passive extension may be
limited by a tight psoas major.45 The flexibility of the psoas
major muscle can be further assessed with orthopaedic
testing using the Thomas test, Yeoman’s test or Gaenslen’s
test.40,43,44 The Thomas test is traditionally thought to help
differentiate tight hip flexors (including primarily psoas
major) from tight quadriceps femoris muscles.43,44 Both
Yeoman’s test44 and Gaenslen’s tests43,44 are generally acknowledged
as sacroiliac joint provocation maneuvers,
however these tests do involve passive hip extension and
observation of hip extension restriction and pain during
these maneuvers could implicate psoas major, particularly
if pain is elicited anteriorly.45