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General Angiology

Angiologia

For medical students4 min readUpdated 2026-10-10

Angiology is a fundamental branch of anatomy dedicated to the study of the structure, development, and function of the cardiovascular and lymphatic systems. General angiology places special emphasis on the embryogenesis of the heart, the formation of vascular beds, and the unique specifics of fetal placental circulation, which changes dramatically immediately after birth.

Heart massIncreases from 17–20 g in newborns to 193 g by sixteen years of age.

Heart primordiumBegins to form during the 3rd week of intrauterine development from mesenchyme.

Umbilical vesselsOne vein carries oxygenated blood, while two arteries carry deoxygenated blood.

Eye fluid outflowAqueous humor drains into the venous sinus of the sclera.

Heart Development in Embryogenesis

The development of the heart muscle begins in the third week of intrauterine development. The initial material is mesenchyme. The process goes through several key stages:

Formation of tubes: Initially, two paired endocardial tubes are laid down in the region of the head gut. Soon they fuse into a single structure with a double-layered wall.
Layer differentiation: The inner layer of this tube gives rise to the endocardium. The outer layer, called the myoepicardial plate (epimyocardium), differentiates into the myocardium and epicardium.
Morphogenesis and chamber separation: The heart tube elongates actively, acquiring a characteristic S-shape. Septa begin to grow within it. The common atrium is established and subsequently divides into right and left parts. A similar process occurs with the common ventricle. Atrioventricular valves and cusps form from endocardial thickenings.
Topography: Initially, the heart is located in the cervical region (ventrally in the anterior mesentery), but as it develops, it gradually descends into the thoracic cavity, becoming covered by the serous membrane.

Fetal Placental Circulation

Before birth, the pulmonary circulation does not participate in gas exchange because the lungs are non-functional and vascular resistance within them is high. Gas exchange is carried out entirely in the placenta (placenta).

Delivery of oxygenated blood: Oxygen-rich blood from the placenta travels via the single umbilical vein (v. umbilicalis), which passes within the umbilical cord through the umbilical ring toward the liver.
Distribution in the liver: Part of the blood passes through the liver parenchyma, connecting with the portal system. However, the bulk is shunted directly via the ductus venosus (ductus venosus) into the inferior vena cava, where it mixes with deoxygenated blood from the lower body.
Intracardiac shunts: In the right atrium, the mixed blood from the inferior vena cava is directed by a specialized valve through the foramen ovale (foramen ovale cordis) directly into the left atrium. This allows the most oxygen-rich blood to enter the left ventricle and subsequently the ascending aorta and aortic arch to supply the heart, head, neck, and upper limbs.
Diversion of deoxygenated blood: Purely deoxygenated blood from the superior vena cava enters the right ventricle, and from there into the pulmonary trunk (truncus pulmonalis). Because the lungs are inactive, this blood is shunted via the ductus arteriosus (ductus arteriosus) into the descending aorta, supplying mixed blood to the lower half of the fetus's body.
Return to the placenta: Blood returns to the placenta for oxygenation via two umbilical arteries (aa. umbilicales dextra et sinistra), which branch off from the internal iliac arteries.

Age-Related Features and Growth Dynamics

The topography and mass of the heart undergo significant changes as a child matures.

Position in the thoracic cavity: In newborns, the heart lies transversely. This is due to the high position of the diaphragm caused by the large size of the liver, as well as the heart being displaced posteriorly by an enlarged thymus. The oblique position characteristic of adults forms only by the end of the first year of life.
Projection of the apex: In a newborn, it is located at the level of the 4th intercostal space, drops to the 5th intercostal space by five years of age, and corresponds to the adult level by 10 years.
Growth dynamics of chambers: In the first months of life, the atria grow faster than the ventricles. By the second year, their growth equalizes. After 10 years, the ventricles begin to develop more intensively, especially the left one.
Heart mass: From 17–20 g at birth, the mass increases to 52–55 g by 1–2 years, reaches 95–111 g by 10 years, and 190–193 g by 16 years. In boys, heart mass is generally greater, except during the puberty period (12–13 years), when girls temporarily surpass boys in this parameter.

Lymphatic System of the Neck and Eye Drainage

General angiology also encompasses pathways of lymph drainage and fluid circulation in specialized organs.

Eye drainage: Outflow of aqueous humor occurs from the anterior and posterior chambers of the eyeball, as well as zonular spaces (spatia zonularia). Fluid passes through the spaces of the iridocorneal angle and enters the venous sinus of the sclera (sinus venosus sclerae), from which it drains into the veins of the eye.

Lymphatic vessels of the neck (vasa lymphatica colli):

Lateral group: Superficial vessels carry lymph toward the external jugular vein and superficial cervical nodes. Deep vessels drain lymph from internal organs (pharynx, larynx, thyroid gland, trachea, esophagus). They head toward deep nodes (including the jugulodigastric node), whose efferent vessels form the right and left jugular trunks (trunci jugulares dexter et sinister).
Anterior group: Drains lymph from the isthmus of the thyroid gland and larynx, interrupting in the paratracheal and prelaryngeal nodes.

Frequently asked questions

Which heart structures form from endocardial cushions (endocardial thickenings) during embryogenesis?

Atrioventricular valves and cusps of the heart develop from endocardial thickenings during embryogenesis. These structures form during the morphogenesis stage when septa appear inside the heart tube to divide it into four chambers.

Atrioventricular valves — each cusp is a fold (duplication) of the endocardium into which connective tissue of the epicardium subsequently grows.

What do the fetal umbilical vein, ductus venosus, and ductus arteriosus obliterate into after birth?

After birth, these vessels undergo obliteration and transform into ligaments:

Umbilical vein (v. umbilicalis) — into the round ligament of the liver (lig. teres hepatis).
Ductus venosus (ductus venosus) — into the ligamentum venosum (lig. venosum).
Ductus arteriosus (ductus arteriosus) — into the ligamentum arteriosum (lig. arteriosum).

Where do the right and left jugular lymphatic trunks empty?

The right jugular lymphatic trunk empties into the right venous angle, whereas the exact termination site of the left trunk requires contextual specification.

Right jugular trunk (truncus jugularis dexter) — merges with the right subclavian trunk, forming the right lymphatic duct (ductus lymphaticus dexter), which empties into the right venous angle.
Left jugular trunk (truncus jugularis sinister) — forms from efferent vessels of the lower deep cervical nodes, though its subsequent pathway varies (commonly draining into the thoracic duct).

Which branches arise from the aortic arch to supply the head, neck, and upper limbs?

Three major trunks arise from the convex surface of the aortic arch, supplying the head, neck, and upper limbs.

Brachiocephalic trunk (truncus brachiocephalicus) — arises first (on the right) and divides into the right common carotid (a. carotis communis dextra) and right subclavian (a. subclavia dextra) arteries.
Left common carotid artery (a. carotis communis sinistra) — arises directly from the aortic arch.
Left subclavian artery (a. subclavia sinistra) — travels upward and to the left toward the cervical region.

Sometimes a thyroidea ima artery (a. thyroidea ima) may additionally branch off from the brachiocephalic trunk.

What type of blood flows through the umbilical vein in a fetus?

Arterial (oxygen-rich) blood flows through the umbilical vein from the placenta to the fetus.

What is the function of the ductus arteriosus (duct of Botallo)?

It connects the pulmonary trunk to the aortic arch, allowing deoxygenated blood from the right ventricle to bypass the non-functional lungs and enter the systemic circulation.

Why does a newborn's heart have a transverse position?

The transverse position is caused by the high standing of the diaphragm due to a very large liver and the pressure of a large thymus, which displaces the heart posteriorly.

Where does lymph from the lateral deep group of neck vessels drain?

It drains into the deep cervical lymph nodes (e.g., the jugulodigastric node), which ultimately form the right and left jugular trunks.

Go deeper

Formation of the truncus arteriosus and venous sinus during embryogenesis.
Mechanisms of obliteration of fetal communications (foramen ovale, ductus venosus, and ductus arteriosus) after birth.
Anatomic prerequisites for sex differences in heart mass during the pubertal period.
Topography of paratracheal and prelaryngeal lymph nodes.
Hemodynamic differences between the ascending and descending aorta in the fetus.