arthritic changes, lumbar models, cervical models

Arthritic changes are very common. They are often related to a person’s pain with neck pain as one of the highest ranked common causes of disability. In this specific research article 1, the authors looked at the micro-details of neck synovial joints. With osteoarthritis known to be related to neck pain, they were looking to reveal higher anatomical detail and they were also curious about whether men or women have more of these problems.

With both neck and back pain being multifactorial (which may include both psychological and social aspects) degenerative changes within the synovial joints play a significant structural role with the development of spondylosis. This is a general term to describe a disorder of the musculoskeletal system with an emphasis on joint space narrowing, intervertebral disc height loss and frequent formation of bony spurs.

The architecture of the cervical facet joints is quite well known with most of the current knowledge around the smooth (or lack of smoothness) hyaline cartilage to allow the joint to receive and distribute loads in an efficient manner. However, there has not been much quantitative data revealing the anatomy under the hyaline cartilage designated as the subchondral bone. This bone under the cartilage (sub, meaning below and chondral, meaning cartilage) has been of recent interest as there exist nerves in this area that can cause pain. This is thought to be similar to the basivertebral nerve of the vertebral body. The innervation of the facet, however, has ascending fibres travelling through the posterior primary division which can be seen in this Medial Branch Dynamic Disc Model.

 

modeling hyaline cartilage, models

Hyaline Cartilage Modeling in our Professional and Academic LxH Dynamic Disc Models

basivertebral nerve lumbar model

Basivertebral nerve of a lumbar vertebra.

Previous research has shown that the thickness of the hyaline cartilage is .4mm in women and .5mm in men with the subchondral bone making up approximately 5% of the total cartilage thickness. It is also known that with increasing age the cartilage starts to flake off (called fibrillation) and researchers also coin the stripping of cartilage from the bone, denudation. This means being nude. A joint surface within a covering. Other terms used to describe the break down of the hyaline cartilage is erosion, fissuring and deformation. All in all, the terminology all mean that the hyaline is thinning.

arthritic changes, subchondral, joint, model

Subchondral thickening – arthritic changes

How did they do it?

These researchers looked at 72 recently deceased people and examined their joints. They used microscopes to look closely at the facet joints to help understand the pathogenesis of the arthritic changes.

When they observed the osteocartilaginous junction, the morphological changes included: flaking, splitting, eburnation, fissuring, blood vessel invasion and osteophytes. They looked at the length of the cartilage, the hyaline cartilage thickness, the calcified cartilage thickness and the subchondral bone thickness.

They found that males tended to have more severe degenerative changes described by flaking and severe fissures in the facet cartilage. Click To Tweet

Points of Key Interest

  • this was a study that looked at 1132 unique cervical spine facets from 72 humans
  • males were found to have more degenerative changes of the osteocartilaginous junction
  • the thickness of the calcified cartilage and subchondral bone increased with age whereas the hyaline cartilage decreased
  • the osteocartilaginous junction is particularly important in the pathogenesis of osteoarthritis in the cervical spine facet joints

 

At Dynamic Disc Designs, we work to bring research to the practitioner so when there is a teaching moment, Professionals are ready to explain pain triggers as they relate to a patients symptoms and movements. Empowering people about their own anatomy helps in the crafting of customized treatment plans for each unique pain patient. Explore our dynamic models and help a patient understand their arthritic changes and what that means to them.

vertebral osteoarthritis

An investigation of degenerative joint disease (DJD) studied data from chimpanzees, lowland gorillas, bonobos, and human samples to ascertain the relative rate of osteoarthritis and peripheral joint osteoarthritis in each species and found that all types of apes were significantly less prone to DJD than humans.

The Study

Museum skeletal samples of adult chimpanzees, lowland gorillas, and bonobos were examined and analyzed for vertebral osteoarthritis (VOP) and osteoarthritis (OE). The resulting data was compared to data sets from a series of adult human skeleton sets wherein comparable analytic methods had been used to determine the rate of VOP and OE. All samples were evaluated for DJD and the presence of VOP. The relative severity of the conditions was scored using ordinal scaling criteria, categorizing the groups into: none, slight, moderate, or severe DJD. The researchers discarded the “slight” sample data and focused instead on the “moderate” to “severe” data sets for the study.

Results

There was a low prevalence of VOP in the ape samples (0-3.8 %) across all vertebral segments, while the human prevalence was between 11 and 85 times that of the apes, with more uniform involvement throughout the vertebral column.

OA of the spinal joints was also rare in African apes, with chimpanzees being least affected, followed by gorillas, and bonobos. Though OA is less prevalent than VOP in humans, it is still three to four times more common in humans than in apes. Broken down into spinal segments, gorillas were more susceptible to cervical and thoracic segments than chimpanzees. Where chimps showed no lumar involvement, gorillas were variably affected at the level. Humans were uniformly more prone to OA at all levels than any of the apes sampled.

Conclusion

Ape samples were much less likely to show signs of spinal degeneration at all levels than comparable human samples. Although it makes sense to assume that the divergence is due to the greater compressive stress on the bipedal human form, the patterning of VOP data in apes and humans suggests that other forces—such as torsional loads related to axial spinal rotation— are likely contributing to the higher incidence of DJD in humans.