Embryological development of the human cranio-facial arterial system: a pictorial review

Abstract

The embryological development of the cerebral vasculature is very complex. Historical and also more recent studies based on human embryos, comparative anatomy and cerebral angiographies allowed us to better understand this vasculature development. The knowledge and understanding of such embryological development are important for physicians interested in neurovascular pathologies. Indeed, all vascular variants and almost all vascular pathologies, such as aneurysms, dolichoectasia, atherosclerosis, and neurovascular conflicts could be explained by an alteration during the embryological life. There are also many variants of these vascular structures present in normal developed adults, which are variably associated with pathological entities. Understanding the process which leads to the development of the normal cerebral arterial system in humans is, therefore, very important to have a better knowledge of the possible clinical and surgical implications of these anomalies. In this paper, we review the embryological development of the cranio-facial arterial vasculature from its beginning at approximately days 21-50 of intrauterine life, with pictures illustrating each developmental phase.

Keywords: Cranial arteries; Embryologic development; Pathophysiology; Variants.

Fig. 1

Padget stage 1; lateral (left) and frontal (right) view of a 4–5 mm,  ≃  30-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from V to XII, developing spinal roots are listed from C1 to C7 and pharyngeal arches from P1 to P4-6.

Fig. 2

Padget stage 2; lateral (left) and frontal (right) view of a 5–6 mm, ≃ 31-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from V to XII, developing spinal roots are listed from C1 to C8 and pharyngeal arches from P1 to P4-6.

Fig. 3

Padget stage 3; lateral (left) and frontal (right) view of a 7–12 mm, ≃ 33-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from III to XII, developing spinal roots are listed from C1 to C7 and pharyngeal arches from P1 to P4-6.

Fig. 4

Padget stage 4; lateral (left) and frontal (right) view of a 12–14 mm, ≃ 36-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from III to XII, developing spinal roots are listed from C1 to C8 and pharyngeal arches from P1 to P4-6.

Fig. 5

Padget stage 5; lateral (left) and frontal (right) view of a 16–18 mm, ≃ 40-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from I to XII, developing spinal roots are listed from C1 to C8. Pharyngeal arches are becoming the respective fetal derivatives.

Fig. 6

Padget stage 6; lateral view of a 20–24 mm, ≃ 45-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from I to XII, developing spinal roots are listed from C1 to T2. The arterial “ring” or loop around the optic nerve is now visible.

Fig. 7

Padget stage 7; lateral view of a 40 mm, ≃ 50-day-old embryo. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. In gray, the outer structure of the embryo is outlined; in yellow, the developing nervous system is represented. Developing cranial nerves are numbered from I to XII, developing spinal roots are listed from C1 to T4. The definitive pre-term vessel configuration is almost completed.