Work

A model of the alar ligaments of the upper cervical spine in axial rotation

Year: 1991

Type: article

Abstract: Although there are seven vertebrae in the human cervical spine, over 50% of the total axial rotation occurs between the first and second vertebrae, at the atlanto-axial joint. Such motion is possible because of the lack of an intervertebral disc and the shape of the articular facets. The limitation of axial rotation, essential because the spinal cord and vertebral arteries cross this joint, is achieved with ligamentous structures, of which the left and right alar ligaments are primary. When one of the alar ligaments was cut in previous tests of human cadaveric spine (n = 10), the axial rotation to both sides significantly increased. This result does not agree with the long-held hypothesis that axial rotation is limited only by the alar on the side opposite rotation. The purpose of this work was to develop a model of the alar ligaments in axial rotation that is consistent with recent experimental observations. This model predicts that both alars must be intact to limit axial rotation; if one alar is injured, the normal mechanism becomes nonfunctional. The model also predicts the observation that a significant percentage of rotation at the atlanto-axial joint occurs freely, without ligamentous resistance. A physical and a mathematical description of the model is presented. Cadaveric experimental data are demonstrated to support the model.

Source: Journal of Biomechanics

DOI: 10.1016/0021-9290(91)90293-v

Authors: Joseph J. Crisco, Manohar M. Panjabi, Jiri Dvorak

Institutions: Yale University, Schulthess-Klinik

Language: English

Topic: Automotive and Human Injury Biomechanics

Subfield: Pulmonary and Respiratory Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,650