Comparative Anatomy of Spinal Anterior and Posterior Longitudinal Ligament

Ossifcation of of posterior longitudinal ligament (OPLL) in cervical spine leads patients to cervical myelopathy. The etiology of this disorder is not clear yet. There is no animal model which simulate human OPLL in pathophisiology. Anatomical and histological observation was performed using Japanese monkey, rabbit, lizard, fowl, frog, and fish. In histological examination elastic and collagenous fibers are observed with EVG and Azan staining. Biomechanical strength of anterior and posterior longitudinal ligament of quad-pedal mammal (rabbit) was measured with TENSILON. Spinal longitudinal ligament was not found in bony fish(ostechthyan) , however in higher class than amphibian spinal longitudinal ligament existed in spinal canal. Spinal longitudinal ligament of avis, reptiles, and amphibian consisted of single layer and had broad continuity to dura mater. On the other hand those of mammalia consisted of deep and superficial layers and had attachment to dura at only peripheral area of disc level. In mammalia, monkey had very similar morphological feature to that of human. There was same feature as for mechanical balance of anterior and posterior longitudinal ligament between human and quad-pedal rabbit. Therefore there was little effect of spinal posture and alignment on development of spinal longitudinal ligament. It seems that local mechanical factor is not main cause of ossification of posterior longitudinal ligament.

比較解剖

脊椎靭帯

バイオメカ二クス

後縦靭帯骨化症