Articolazione sacroiliaca: anatomia, funzione e potenziali implicazioni cliniche

Vleeming A, Schuenke MD, Masi AT, Carreiro JE, Danneels L, Willard FH. The sacroiliac joint: an overview of its anatomy, function and potential clinical implications. J Anat. 2012 Dec;221(6):537-67. doi: 10.1111/j.1469-7580.2012.01564.x

This article focuses on the anatomy and biomechanics of the pelvic girdle and, specifically, the sacroiliac joints (SIJs). The SIJs are essential for effectively transferring loads between the spine and legs.

Although topographical classifications such as ‘sacroiliac’, ‘pelvis’ and ‘spine’ serve a crucial didactic purpose, they can impede our understanding of normal and altered functional mechanisms.

Topographical anatomy helps us to understand the constituents of our body. However, no anatomical structure functions in isolation, and the mechanical load encountered anywhere in the body is distributed through a continuous network of fascia, ligaments and muscles supporting the entire skeleton.

Therefore, the sacrum, pelvis and spine, and the connections to the arms, legs and head are functionally interrelated through muscular, fascial and ligamentous interconnections. Likewise, efficient motor control does not provide a solution for individual joints, but orchestrates efficient reaction forces to integrate and stabilize the kinematics of our body. Focusing on singular anatomical structures to comprehend lumbopelvic pain, rather than considering the spine and pelvis as an integrated, interdependent and dynamic biological structure, might ‘blind’ the observer to the larger picture (Vora et al. 2010).

Functional anatomical and biomechanical models are required to analyze a puzzle as complex as low back pain (LBP) and pelvic girdle pain (PGP). Such an approach can help us understand that seemingly different structures are functionally related. In this respect, we quote Radin, who stated, “Functional analysis, be it biological, mechanical or both, of a single tissue, will fail as in all complex constructs, the interaction between the various components is a critical part of their behaviour” (Radin, 1990).

Unlike standard topographic anatomy schemata, functional anatomy should present the necessary information to comprehend the complex interrelationships between muscle, its internal fascial skeleton and the surrounding external fascial network into which it is integrated. Such an approach can be easily missed in traditional anatomical dissection, yet can be achieved by dissecting the continuity of connective tissue as an integrating matrix (Van der Wal, 2009). Insight into intra- and extra-muscular myofascial force transmission in the locomotor system may be an essential component when studying the functionality of the locomotor system (Huijing & Baan, 2003). In this overview of the SIJ, the literature will be analyzed from both a topographic and functional perspective and the relevant clinical implications presented.