Normative Dynamic & Magnetic Spine

Spinal diseases and deformities in adults (degenerative or traumatic) and children (scoliosis and kyphosis) are major public health issues.

Postural imbalance due to spinal deformity is usually measured on static radiographs, using standard X-rays. However, bipedal walk is characteristic from human being and the trunk is the main stabilizer.

Pathogenesis of spinal deformities remains undefined. To understand the different mechanisms involved in the pathological field, normal musculoskeletal performances of the spine, in static and dynamic conditions must be identified.

Ultra-low doses stereoradiography using the EOS system allows the acquisition of full-spine images in standing position. Furthermore, 3D reconstruction can also be create from both anteroom-posterior and lateral side view. Stereoradiography is used in clinical routine especially in children spinal deformities.

High resolution muscular MRI is the only device that can provide a detailed muscular analysis, with detection of abnormalities at an early stage. No mapping of normal paraspinal muscles has been yet realized, particularly regarding to rotatores muscles.

Motion analysis is the reference exam to analyse dynamic stability during gait. Several parameters reflecting stability during gait can be collected in different conditions. Recently, the "Dynamic Stability Margin" has been developed but no standard values especially in healthy children has been published.

• EOS full-spine, MRI, gait analysis (Other): full-spine stereoradiography, high-resolution spine muscle MRI and 3D gait analysis will be performed

Primary outcomes

• Normal dynamic stability margin (DSM) in children and adults [2 hours]: DSM= xCoM (extrapolated center of mass)- BoS (Base of Support). Unit = meters Normalized on body height (m)

Secondary outcomes

• number of rotatores muscles [2 hours]: counting every rotatore muscle (from MRI data), no unit
• volume of back muscles [2 hours]: from segmentation of each muscle group, unit = voxel

Sex: All, ages: 8 Years to 40 Years, accepts healthy volunteers

Inclusion Criteria:

* Informed consent signed by adult or by the holders of parental authority for the children and adolescents
* Child or teenager, male or female, aged from 8 years to 17 years inclusive
* Adult, male or female, aged from 18 years to 40 years inclusive
* Realization of a preliminary medical examination

Exclusion Criteria:

* Refuse to participate to the study
* Patient under guardianship or curatorship
* Inability to cooperate
* Pregnant woman
* Non affiliation to social security
* Subject with spinal and/or lower limbs affection
* Subject with antecedent of spinal and/or lower limbs surgery
* Subject with contraindication to MRI
* Refusal of the parent or the subject to be informed about a fortuitous discovery during the examinations of the exams