Raynauds phenomenon is commonly seen in

. It is an episodic vasospasam,especially aeriolar spasam usually bilateral more often seen in upperlimb of females as a result of abnormal sensitivity to cold.Patient develops blanching,cyanosis qnd later flushing .usually medial four digits and palm are involved.Thumb is spared.If vasospasam becomes longer,gangrene or ischemic ulceration supervenes along the tips of fingers. Refer page no 183 of SRB's manual of surgery5th edition.