Schmorl's Nodes in individuals from the 21st Century Identified Skeletal Collection (CEI/XXI) University of Coimbra (Portugal)

Schmorl's nodes (SN) are identified by a depression in the surface of the vertebral body and most commonly affect the lower thoracic and lumbar regions of the spine, being prevalent in both modern and historical populations. The main objective of this study is to estimate the prevalence of SN in a sample of 128 adult individuals (81 females and 47 males) from the 21st Century Identified Skeleton Collection (Department of Life Sciences, University of Coimbra). Additionally, we aim to delineate their anatomical distribution in the vertebral column and investigate potential associations with biological sex and age at death. A total prevalence of 61.7% was recorded, identical for both sexes. The age at death for individuals with SN (mean = 80.7 years; SD = 8.1) is nearly identical to those without SN (mean= 81.7 years; SD = 9.9). Therefore, no associations were found between the presence of SN and biological sex or age at death - in a con-text where there is high variability in reported prevalences according to sex and age. The majority of lesions, often located in the center of vertebral bodies, were classified as severe. The most affected vertebrae were L1 (3.0%), L2 (2.9%), as well as T11 and T12 (both with 2.8%). In fact,the thoracolumbar region was the most affected, possibly because it is under a greater stress, along with biomechanical constraints associated with the bipedal posture. Intervertebral discs are also thinner in that part of the vertebral column. The results indicate a high prevalence of SN in this sample, comparable to the higherfrequencies reported in the medical and paleopathological literature.