Embryology of the Vascular System ECNR 2016
UCL Institute of Neurology Queen Square, London
Endothelial cells
Pericytes Smooth muscle Connective cells Charles Raybaud
Primitive streak neural crest Ectoderm neural tube Mesoderm
pharyngeal pharyngeal endoderm endoderm
Endoderm
endothelial cells endothelial cells NEURAL CREST CELLS (NCC)
Arteries of the pharyngeal arches
1st pharyngealpouch
Endoderm Internal carotid
Dorsal aorta Vitelline arteries
Arterial vitelline plexus
Umbilical arteries Larsen, Human Embryology
3 Metameric Territories from Which Arteries Derive
A: rostral mesoderm supplies Prosencephalon
B: middle mesoderm supplies Diencephalon 1st branchial arch derivates
C: caudal medoderm supplies Mesencephalon Metencephalom 2nd brachial arch derivates
Development of Cerebral Arteries Endothelial Vasculogenesis
Vascularisation of the brain adapts continuously to changes in shape size metabolic demand
Blood supply adapts metabolic demand of brain activity
Morphological changes in neural tissue reshape the arterial tree
week 4 week 5
Raybaud Neurosurg Clin N AM 2010 Embryology of Carotid System Embryological Segments of ICA
Regressions 1st and 2nd aortic arches
Formation of ICA prim. mandibular a.
caroticotympanic a.
1 ventral aorta 2 dorsal aorta Embryonic ICA segments 1 cervical 15 dorsal ophthalmic a. 2 ascending intra-petrous 16 ventral ophthalmic a. 3 horizontal intra-petrous 17 MCA 4 ascending foramen lacerum 18 ACA 5 horizonantal intracavernous 20 anterior choroidal a. 6 clinoid 7 termination
Intracranial ICA Connection of Anterior and Posterior Circulation Week 5
Telencephalic portion of brain
Diencephalic Termination Cranial portion of brain division
phylogenetic Mesencephalic ICA portion of brain Termination Caudal division
Raybaud Neurosurg Clin N AM 2010
PChorA Collic a Sup cer a aica pica
anterior component of the (limbic) ring : anterior cerebral artery
posterior component of the (limbic) ring : anterior choroidal artery Simultaneously the both - supply the choroid plexus and anastomose at the level of the ventral longitudinal axes fuses in the midline to form the interventricular foramen (Monro) basilar artery and the ASpinalA - present telencephalic branches anastomosing at the surface of the vesicles Phylogenetic Aspects Embryology of Cerebral Arteries: Main Concepts
The ACA is a terminal branch of the ICA with various opotions for midline anastomoses The MCA is a branch of the ACA developing after the recurrent artery of Heubner The anterior choroidal artery is an old artery and anastomosis with the ACA, supplying the limbic system. The PCA belongs to caudal division of ICA It will annex cortical territory from the anterior choroidal artery The basilar artery results form cranio-caudal fusion of the posterior division of the ICA
Opossum: Full Limbic Ring
Development of Anterior Cerebral Artery Development of Middle Cerebral Artery
Primitive olfactory artery as MCA (2) arises from ICA, initial termination of ICA distal to anterior choroidal artery (1) ACA is continuation MCA extends laterally over primitive olfactory artery , surface on brain extending upwards and Depression and invagination backwards over lateral aspect of brain Regression of primitive (formation of opercula and olfactory artery insula) is followed by MCA
Development of Posterior Cerebral Artery Aberrant ICA
Foetal
Gives rise mesencephalic, diencephalic and posterior choroidal and cortical vessels Shifts dominant supply to basilar artery with partial regression of PCOM artery Aberrant ICA Anterior Communicating Artery Complex involution of the normal cervical portion (first embryonic segment) of the ICA Enlargement of collateral pathways inferior tympanic artery (ITA) caroticotympanic artery (CTA)
ACA Variants Foetal L PCA
Foetal R PCA Fusion of Basilar Tip- Possibilities Symmetrical Cranial Fusion Symmetric Caudal Fusion
Revista Argentina de Neurocirugia 2013 Revista Argentina de Neurocirugia 2013
Asymmetrical Caudal Fusion Cobrahead Tip
Revista Argentina de Neurocirugia 2013
Basilar Tip Configuration on DSA Vertebral and Basilar Variants
Normal Basilar Tip: 30.4% Cranial Symmetrical 26.1% Caudal Symmetrical 43.5% Caudal asymmetrical
Basilar Tip Aneurysms 9 % Cranial symmetrical 51% caudal symmetrical 40% Caudal asymmetrical
Campos et al Interv Neuroradiol.1998 Basilar Fenestration Vertebral Artery Fenestration
distal
proximal
PICA Termination of R Vertebral Artery Persistent Vestigial Arteries Embryonal Pattern
tga trigeminal artery oa otic artery hga hypoglossal artery paa proatlantal artery
Hypoglossal Artery Trigeminal Artery
Hypoglossal Artery Trigeminal Artery Choroidal Stage
Tela choroidea and plexuses drained by a single, median dorsal bridging vein (median prosencephalic vein of Markowski) that antecedes the development of the internal cerebral veins and vein of Galen
Week 6: Three Venous Plexuses (ant, mid and post) Week 8 and 9
mpvm = median prosencephalic vein of Markowski (7) dv = diencephalic vein ts = transverse sinus 5 + 6 = sigmoid sinus OC = Otic Capsule
Month 3 Vein of Galen Aneurysm
early late 11 = middle cerebral vein 12 = superior sagittal sinus 13 = tentorial plexus 14 = internal cerebral veins Vein of Galen Aneurysmal Malformation (VGAM) ASL in Vein of Galen Aneurysmal Malformation (VGAM)
In utero
day 1
Courtesy of Madgalena Sokolska
Neonate SWI A Special Thank You To
Majda Thurnher
Timo Krings
Karel Ter Brugge
George Rodesch