Sergio Marcucci

Sergio Marcucci

A.T. Still University of Health Sciences, USA

Title: Sacroiliac joint biomechanics and its potential clinical implications


Sergio Marcucci has received his M.Sc. from A.T. Still University of Kirksville and D.O. from Sutherland College of Osteopathic Medicine, Belgium. He is practicing at private office of osteopathic medicine in Luxembourg since 11 years. His major research interests include biomechanics of sacroiliac joints, determining its potential clinical influence for the practitioner and analyzing scientifically symptoms of musculoskeletal dysfunction, thus trying to understand the mechanism from different osteopathic manual techniques applied for musculoskeletal dysfunction with the aim to reach a physiological process again.


The sacroiliac joint (SIJ) is the largest axial joint in the body, with an average surface area of 17.5 cm². SIJ is a true diarthrodial joint and is innervated by branches of the posterior rami of L4-S3 nerve roots. For several authors, SIJ is a potential pain generator that must be considered within the differential diagnosis of low back pain. Various studies have reported SIJ as the primary pain source in 10% to 26.6% of cases in the control group, compared to anesthetic blocs group qualified as “Gold standard” by the International Association for the Study of Pain (IASP). According to Robert et al. SIJ is a joint with only few degrees of movement and is designated to a spontaneous arthrodesis and is also a transmitter of load between spine and ilium.
SIJ is supported by a strong passive, viscoelastic ligamentous system for providing stability. Pain of SIJ can be expressed by structures, immediately surrounding the joint or sometime at distance, through entesopathies in front or at distance from SIJ. Some SIJ pain could have especially their source in the ligaments, but therefore also more difficult to differentiate them, from pain arising from structures in the neighboring SIJ: i.e., thoracolumbar fascia, lumbosacral plexus, branches from sacral nerve roots, sciaticnerve, posterior cutaneous nerve of thigh, nerves from thoraco-lumbar junction. The difficulty of the clinical assessment of its dysfunction, and uncertainties as to the pathogenicity of blockages or conversely extreme laxity of the SIJ, allow plenty of speculation as to the responsibility of the SIJ in the occurrence of buttock pain or lumbar.The range of motion of the SIJ is estimated to be about 2 to 4 degrees. Most of biomechanical studies detected a helical axis, which indicates the existence of a three dimensional movement of the SIJ.
The major movement is situated in the sagittal plane. This presupposes that the intersection point of the axes of motion in the sagittal plane is situated behind the sacrum, in the region of posterior ligaments and the iliac tuberosities. On the other hand, the IASP lists four criteria for the syndrome of SIJ. A key criterion is a normal joint from a morphological point of view without the presence of a radiograph pathognomonic abnormality. This important criterion is supplemented by the following three criteria: Pain in the region of the SIJ, the reproduction of pain by manual tests that stress the joint and finally the relief of pain by intra-articular injections. Finally for McGrath putative SIJ pain, of the “SIJ syndrome” presents a number of substantial clinical challenges. First, where is the pain generator in the absence of discernible pathology? Second, do SIJ pain provocations tests achieve what they purport to achieve? Third, do physical tests stress the joint to the exclusion of all other potential generators? Fourth, are all pain generators in the region identified? Fifth, is intra-articular injection an effective “gold standard” for the elimination of putative SIJ pain?

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