###### Abstract  
Background: This study aimed to investigate the association between the internal derangement of the temporomandibularbular joint (TMJ), in particular the severity of disc displacement (DD), and the presence of generalized joint hypermobility (GJH) in growing patients evaluated on magnetic resonance images (MRIs). The study also investigated the relationship between the stages of DD severity and age. Methods: This cross-sectional study has been conducted on a pre-orthodontic population (8-16 years). The GJH was assessed with the Beighton test (cutoff \(\geq\) 4) and the final sample of 56 patients was divided into two groups: a study group, 30 subjects with GJH, and a control group, 26 subjects without GJH. The disc position was evaluated on MRI and the severity of DD was classified in four stages. [PERSON]'s \(\chi\)2 Test was performed for the analysis of the statistical correlation. Results: A statistically significant relationship between GJH and disc position was found, in particular, a disc displacement with reduction (DDwR) and DD severity. A positive association also emerged between the severity of DD and age, that increased with increasing age. Conclusions: The research results suggest that there is an association between the presence of generalized joint hypermobility (GJH) and disc displacement (DD) in growing patients. Growing patients with GJH showed a higher severity of DD. In older patients, greater severity of DD was evident, suggesting that this condition may worsen with age during growth. t 2023 20  
for an orthodontic clinical examination [12] with a higher incidence of symptomatic TMJ DD in late teenager years [13]. The diagnosis of DD is predominantly clinical, through the clinical evaluation protocol of the diagnostic criteria for TMDs (DC/TMD). Clinically, DDs can be classified according to the DC/TMD into disc displacement with reduction, disc displacement with reduction with intermittent locking, disc displacement without reduction with limited opening, and disc displacement without reduction without limited opening [1]. The diagnosis of DD can be confirmed by MRI, considered the gold standard for the evaluation of the articular disc. On MRI images, DD can be classified into disc displaced with reduction (DDwR) and disc displaced without reduction (DDwoR) according to the position the disc takes in a closed mouth and an open mouth [1]. Several studies have investigated the etiopathogenesis of DD, including macro- and microtrauma in the joint, lack of muscle coordination, changes in TMJ lubrication, postural disorders, stress, and depression [11; 14; 15]. Likewise, the anatomical and functional changes of the osseous structures of the TMJ have been associated with disc displacement [16; 17; 18; 19; 20; 21; 22]. Joint hypermobility has also been associated with DD [23; 24; 25]. Joint hypermobility (JH) is a term that describes the ability of a singular or multiple joints to move beyond the normal physiological limits, and it is considered more as a descriptor rather than a diagnosis; it can be observed as localized joint hypermobility or as general hypermobility (GJH) when it affects multiple joints [26]. The most common method used for assessing GJH is the Beighton Score (BS), a set of tests in a nine-point scoring system. It was initially developed as an epidemiological tool used for screening large populations, but later, it has been utilized as a clinical tool for diagnosis of GJH [27; 28]. In a review of the clinical presentation of DD, it is suggested that in patients with DD the structures of the TMJ can adapt and that the progression is extremely benign in most cases [29]. However, the studies included in the review are of adult patients and in no case was the presence of GJH considered. Adolescents with GJH seem to have a greater predisposition to present DD, especially disc displacement without reduction [23]. To the best of our knowledge, there are no studies in the literature on the correlation between different degrees of severity of DD and GJH in growing patients.