Inclusion Criteria:  Instability Group  Patient, male or female, over 18 years old and up to 40 years old Patient operated for antero-inferior shoulder instability Subject affiliated or beneficiary of a social security scheme Patient having signed the free and informed consent comparativ group Patient, male or female, over 18 years old and up to 40 years old Patient operated for a reason other than unstable shoulder Subject affiliated or beneficiary of a social security scheme Patient having signed the free and informed cons  Exclusion Criteria:  History of surgery on the affected shoulder Capsuloligamentous disease (Ehler Danlos) History of instability (dislocation, subluxation) in witnesses Patient participating in another clinical study Protected patient: adult under guardianship, curatorship or other legal protection, deprived of liberty by judicial or administrative decision; Pregnant, breastfeeding or parturient woman; Patient hospitalized without consent.