Anatomical Variations of the Circulus Arteriosus in Cadaveric Human Brains

Table 10

Comparison of morphological variations of P1.

Variation type P1	Present study %	Kapoor et al. [17]	Alpers et al. [12]	Al-Hussain et al. [29]
Absent	2.66	—		—
Hypoplasia	6	10.6	6.3	1
Duplication	2	2.4		—
Fenestration	1.33	—		—
SCA + P1 stem	2	—		—
Symmetrical	77.33	—		—
Asymmetrical	22.66	—		28