Theoretically in this case it would be the question of pathology of muscles and tendons responsible for the movement of the joint either from causes affecting the tendon and muscle (rupture, inflammation, myopathic changes) or a disorder of receptors, which innervate this muscle6. Anatomical structures of the joint should be intact.
A real occurrence of the normal extension
of the passive movement with a present restriction of the extension of the
active movement in the glenohumeral articulation
From the examples mentioned above with regarding to a frequency of diagnosis, we would suppose a frequent finding of the restriction of the extension of the active movement at normal extension of the passive movement. But the reality is different. Let's introduce as an example of full rupture of the rotator cuff when the patient is not theoretically able to make the abduction by his/her strength, but the doctor is able to make the passive abduction in the full extension. The real finding at the examination is different than it was expected:
In the acute state we find such pains that the patient refuses to make any movement – active or passive – and the examination is not possible.
In the later state we meet expected restriction of the extension of the active movement, and also the restriction of the extension of the passive movement because the damaged rotator cuff, hypertrophy of the articular capsule and frequent articular filling impede its realization.
6 at plegia of the limb the restriction of the extension of the active movement occurs, but the extension of the passive movement is normal only at the beginning of this rupture (after a certain time a development of contractures occurs)