Libelle of note

For the Arteria carotis interna (Internal carotid artery or ICA, the subdivision into C1-C4 segments (Gibo et al. 1981 J Neurosurg 55:560-574) is replaced by the more recent Bouthillier subdivision into C1-C7 (Bouthillier A, van Loveren HR, Keller JT 1996 Segments of the internal carotid artery: A new classification. Neurosurgery 38:425-433). Main differences are: - the Pars lacera (Segmentum C3) is a short segment that begins above the Foramen lacerum and ends at the Ligamentum petrolinguale. The new Segments C2 and C3 cover the old Segment C2; - the Pars cavernosa is the new Segmentum C4; - the Segments C5-C7 comprise the Pars cerebralis (C4) of the Gibo/TA subdivision: the Pars clinoidea (Segmentum C5) is a borderline segment extending between dural rings, by definition never intradural, often surrounded by a venous collar (a protrusion of the Cavernous sinus), the Pars ophthalmica is Segmentum C6, and the Pars communicans Segmentum C7.

The Sipho caroticus (Carotid siphon), described by Moniz in 1927, is not well-defined. It covers the C4-C5/C6 segments (see Sanders-Taylor C, Kurbanov A, Cebula H, Leach JL, Zuccarello M, Keller JT 2014 The carotid siphon: A historic radiographic sign, not an anatomic classification. World Neurosurg 82:423-427).