Characteristics of the Three Ligaments of Human Spring Ligament Complex from a Viewpoint of Elements

To elucidate characteristics of the three ligaments constituting the spring ligament complex from a viewpoint of elements, the authors investigated age-related changes of elements, relationships among their elements, relationships among ligaments in the elements, and gender differences in the three ligaments of the spring ligament complex, the superomedial calcaneonavicular (SMCN), inferoplantar longitudinal calcaneonavicular (ICN), and third or medioplantar oblique calcaneonavicular (TCN) ligaments. After ordinary dissection at Nara Medical University was finished, the SMCN, ICN, and TCN ligaments of the spring ligament complex were removed from the subjects. The subjects consisted of 10 men and 12 women, ranging in age from 62 to 99 years (average age = 80.5 ± 9.7 years). After incineration with nitric acid and perchloric acid, the element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that although the Ca and P content hardly changed in the SMCN ligament with aging, the Ca and P content in the ICN ligament increased to about three and five times higher in the 80s in comparison with the 60s, respectively, whereas in the TCN ligament, it increased about 40% and 90% higher in the 80s compared with the 60s, respectively. Regarding the relationships among elements, significant direct correlations were found among the contents of Ca, P, and Mg in all the three ligaments of the spring ligament complex. This finding was in agreement with the previous finding obtained with the three ligaments of the anterior cruciate ligament, posterior longitudinal ligament, and ligamentum capitis femoris. Whether there were significant correlations among the three ligaments of the spring ligament complex with regard to the Ca, P, S, Mg, Zn, and Fe contents was examined using Pearson’s correlation. It was found that there were significant direct correlations between the SMCN and TCN ligaments in all the Ca, P, Mg, and Zn contents and also between the SMCN and ICN ligaments in both the Mg and Fe contents but not between the TCN and ICN ligaments in the six element contents. Regarding the gender difference in elements, a significant gender difference was found only in the Mg content of the SMCN ligament, being significantly higher in men than in women.