RicSum

Hello, I have been trying to find info regarding the "perivascular sheath" but can not find a simple explanation anywhere. A medical journal that I read some time ago said that when an artery is completely transected, vasospasm occurs and the artery then often retracts into the perivascular sheath. I fully understand the concept of vasospasm, but have never heard of the perivascular sheath before. Am I right to believe that it is similar to the carotid sheath - i.e a connective sheath which surrounds arteries? If so, do all arteries have such a sheath or only certain sized arteries? Also, what exactly is the purpose of this sheath? I look forward to any replies but please do not suggest googling "perivascular sheath", as I have already tried that but could not find a clear explanation. Thank you all in advance.