The aim of the study is to determine if postocclusive hyperemia of palmar and dorsal face of the hand with Laser speckle contrast imaging discriminate between patients with systemic sclerosis, subjects with primary Raynaud's phenomenon and healthy subjects.

Microvascular dysfunction is a key event in the pathogenesis of systemic sclerosis. There are currently no test measuring it in clinical practice. Response to humeral occlusion is interesting and this response has been studied with laser Doppler flowmetry. More recently, laser imaging has been used analysing the granularity of the laser: laser Speckle Contrast Imaging which allow combining high temporal resolution to high spatial resolution.

The investigators proposed, in this study, to compare this imaging at basal and after post-occlusive hyperaemia of dorsal and palmar face of hand in 3 groups: healthy subjects, primary Raynaud's phenomenon and systemic sclerosis.

Inclusion Criteria:

• Healthy subjects:
• Man ou woman 18 years old or more.
• Without Raynaud's phenomenon or systemic sclerosis.

Raynaud's phenomenon subjects:

• Man ou woman 18 years old or more.
• with primary Raynaud's phenomenon.

Systemic sclerosis:

• Man ou woman 18 years old or more.
• systemic sclerosis in accordance to Leroy's classification.

Exclusion Criteria:

• active digital ulceration
• Bosentan, iloprost ou sildenafil treatment
• History of axillary dissection , trauma or surgery
• history of thromboembolic disease or thrombophilia
• minor or law-protected major
• exclusion period in another study
• No affiliation to medicare
• pregnant, parturient or breasting woman
• concomitant serious disease: progressive cancer, liver failure, history of myocardial infarction less than 5 years, angor
• smoking in the 6 last months
• person deprived of liberty by a legal or administrative decision, person under legal protection
• maximal annual indemnification reached.