Fig. 2From: Experimental determination of three-dimensional cervical joint mobility in the avian neckMeasuring zygapophyseal overlap. Left dorsolateral view of two articulating vertebrae. a. Distance change during dorsiflexion, where the zygapophyses are pushed together. b. Distance change during ventroflexion, where the zygapophyses are pulled apart. Distance measurements represented in purple. L: The length of the prezygapophysis; used to standardize the distance measurement (D z ). D z : The amount of postzygapophyseal overlap with reference to the prezygapophysisBack to article page