To determine the postural role of longus colli (LC) and dorsal neck muscles, we have studied the relationship between their cross-sectional areas related to their force of contraction and the lordosis and the length of the cervical spine. This study was carried out in 36 healthy subjects. Muscle cross-sectional areas were measured by computerized tomography. The index of lordosis and the length of the cervical spine were measured on an X-ray profile. The cross-sectional area of LC was correlated to the lordosis index (R = -0.432, p < 0.02) whereas all the other parameters were not correlated. The authors conclude that LC counteracts the lordosis increment related to the weight of the head and to the contraction of the dorsal neck muscles. Postural functions of LC and postcervical muscles are complementary. They form a sleeve which encloses and stabilizes the cervical spine in all positions of the head.
SUMMARY Immunisation with heterologous type II collagen (CII) induces arthritis in mice of the DBA/1 strain, which is genetically susceptible to this disease. To develop an experimental model of autoimmunity more adequate for the study of human rheumatoid arthritis (RA), DBA/1 mice were injected with 100 ,tg of native CII that had been purified from mouse xiphoid cartilage. About six weeks later the animals developed a chronic progressive polyarthritis involving the four paws but mainly confined to interphalangeal and metatarsophalangeal joints. The evolution of the disease fluctuated between remissions and exacerbations. The initial lesions assessed by clinical observations were more severe when the disease occurred early than in the case of late onset. Interestingly, the incidence of arthritis was clearly preponderant in males, and, moreover, the few female mice which developed arthritis had mild disease states with lower arthritic scores than the males. Varying levels of autoantibodies against mouse CII were found in the sera of immunised animals, regardless of the development of arthritis. These data indicate that the injection of homologous CII into mice caused a polyarthritis that is clinically closer to the human RA than the disease induced with heterologous CII and therefore will represent a useful tool for the study of the self-perpetuating mechanisms that characterise RA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.