The sensitivity and specificity of special tests in physiotherapy is sometimes unreliable, this is due to differential diagnosis and the palpable skills of different therapists. My particular research focuses on the fact that we have a natural postural asymmetry which is explained in my normal posture blog.
These postural asymmetries will effect special tests in the following examples:
Single leg stance
Effect- the right leg will fall into valgus with a supposed “foot strategy” for balance, this is due to the right abductors being naturally lengthened due to the tilted pelvis. There will be worse balance on the left foot and a supposed “hip strategy” for balance, this is due to the left foot being everted and the arches of the foot being reduced.
Apleys scratch test
The right arm will reach up the back to a lesser extent then the left. I am not sure why.
Impingement test i.e. Hawkins
The right shoulder will more often test positive due to the right acromion process pointing downwards and the greater tuberosity more readily interfering with the structures in between both structures.
There will be less strength in the right medial glute during end of range abduction, actually strength is likely to be the same but in a more adducted position for the right and strength would be the same for the left in an abducted position.
Left proximal hamstring pathology in the left hamstring as the left ilium is held in relative anterior pelvic tilt compared to the right which increases the extent of hip flexion during running which can irritate the tendon attachment on the ischial tuberosity. Also the left hamstrings are more dominant then the right which may increase the load on the left hamstring tendon (this is a subjective view)
Right Shoulder impingement- as explained above, the right acromion process is tilted downwards which makes the greater tuberosity of the humerus rub more easily against structures underneath the acromion process such as bursa or the rotator cuff tendon.
Right Lower back pain- This is due to the right leg being held in adduction, the right abductors then work overtime to maintain pelvic stability as the left leg swings forward. Continuos tension in the right abductors may put pressure on the nerves (lateral gluteal nerve?).
There is also a convex curve towards the left in the lumbar spine, this may reduce space in the right facets of the vertebrae which may reduce space in the foramen causing impingement on the right lumbar nerves exiting the vertebrae.
Left hip femoral anterior impingement- This is due to the left ilium being held in anterior pelvic tilt relative to the right (nutation), this means the left hip is held in relative hip flexion and so causing more rubbing of top of the ip on the anterior labrum.
Right Adduction strain- as the right leg is held in adduction the right abductors and adductors work overtime to maintain pelvic stability.
Left plantar fasciitis and left medial ankle pain- this is caused by the left foot being everted causing stretching to the posterior tibialis which also can irritate the tibial nerve along the underside of the medial malleolus
Right lateral ankle sprains- the right foot is more inverted and as there is less pronation the right ankle is more likely to turn over.
Left medial ankle sprains- although less likely as the foot is everted there is more of a stretch on the deltoid ligament.
Left piriformis syndrome- this is caused by the left hip being held in relative internal rotation, putting the piriformis on slack which can irritate the left sciatic nerve.
Left patellar pain- as there is more weight bearing on the left leg, the left knee will absorb more pressure overtime and may cause degeneration of the left knee cartilage.