"persistent primitive trigeminal artery (PPTA), seen in 0.1-0.6% of cerebral angiograms; bilateral PTAs extremely rare. PTA arises where the ICA exits the carotid canal to enter the cavernous sinus; it then runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%) before joining the basilar artery. Usually associated with a small PCOM and vertebrals, as well as a hypoplastic basilar caudal to the anastomosis of PTA (increased incidence of AVMs and aneurysms)."
"persistent primitive hypoglossal artery (PPHA), seen in 0.027-0.26% of cerebral angiograms. It courses through the hypoglossal canal, parallel to the nerve, connecting the cervical ICA with the basilar artery. When present, it is functionally a single artery that supplies the brainstem and cerebellum (often associated with aneurysms)."
"It is named after the English physician Thomas Willis (1621–1675), who first described the anatomy of his circle in 1664 in his book "Cerebri anatome: cui accessit nervorum descriptio et usus" (The Anatomy of the Brain and Nerves). He called his discovery the "circulus arteriosus cerebri" 2. He was also responsible for the numbering of the cranial nerves, still used to this day 2. He died in 1675 from pleurisy and his remains are buried at Westminster Abbey in London, UK 2."
"persistent primitive trigeminal artery (PPTA), seen in 0.1-0.6% of cerebral angiograms; bilateral PTAs extremely rare. PTA arises where the ICA exits the carotid canal to enter the cavernous sinus; it then runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%) before joining the basilar artery. Usually associated with a small PCOM and vertebrals, as well as a hypoplastic basilar caudal to the anastomosis of PTA (increased incidence of AVMs and aneurysms)."
"persistent primitive trigeminal artery (PPTA), seen in 0.1-0.6% of cerebral angiograms; bilateral PTAs extremely rare. PTA arises where the ICA exits the carotid canal to enter the cavernous sinus; it then runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%) before joining the basilar artery. Usually associated with a small PCOM and vertebrals, as well as a hypoplastic basilar caudal to the anastomosis of PTA (increased incidence of AVMs and aneurysms)."
"It is named after the English physician Thomas Willis (1621–1675), who first described the anatomy of his circle in 1664 in his book "Cerebri anatome: cui accessit nervorum descriptio et usus" (The Anatomy of the Brain and Nerves). He called his discovery the "circulus arteriosus cerebri" 2. He was also responsible for the numbering of the cranial nerves, still used to this day 2. He died in 1675 from pleurisy and his remains are buried at Westminster Abbey in London, UK 2."
Expected headings
"Common variants"
"Carotid-vertebrobasilar anastomoses"
"Branches of the circle of Willis also supply the optic chiasm and tracts, infundibulum, hypothalamus and other structures at base of brain:"
"persistent primitive trigeminal artery (PPTA), seen in 0.1-0.6% of cerebral angiograms; bilateral PTAs extremely rare. PTA arises where the ICA exits the carotid canal to enter the cavernous sinus; it then runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%) before joining the basilar artery. Usually associated with a small PCOM and vertebrals, as well as a hypoplastic basilar caudal to the anastomosis of PTA (increased incidence of AVMs and aneurysms)."
"persistent primitive trigeminal artery (PPTA), seen in 0.1-0.6% of cerebral angiograms; bilateral PTAs extremely rare. PTA arises where the ICA exits the carotid canal to enter the cavernous sinus; it then runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%) before joining the basilar artery. Usually associated with a small PCOM and vertebrals, as well as a hypoplastic basilar caudal to the anastomosis of PTA (increased incidence of AVMs and aneurysms)."