Arterial variants and anomalies

Variants and anomalies of arteries in most cases can be divided into four groups:

1. absence of an artery and its replacement by branches of neighboring arteries;
2. change in the origin of the arteries;
3. unusual topography of the arteries;
4. presence of an additional artery.

The coronary arteries of the heart can often arise from the aorta directly above its semilunar valves (12% of cases). Sometimes the coronary arteries begin from the left subclavian artery. Often there are one or two additional coronary arteries.

The aortic arch is sometimes shortened, rarely bends to the right, located above the right main bronchus. Very rarely, the aortic arch is doubled, both aortas embrace the esophagus and trachea on both sides. In 7-12% of cases, there are variants of branches departing from the aortic arch. The number of branches is from 1 to 7. Sometimes both common carotid arteries depart as a single trunk. Often, the right common carotid and right subclavian arteries depart separately from the aortic arch. One or two vertebral arteries may depart from the aorta.

The common carotid artery has a dilation (bulb) at its origin in 77% of cases. In 33% of cases, the dilation is at the origin of the internal carotid artery, in 45% - at the level of its middle part, in 33% of cases - at the origin of the external carotid artery.

The superior thyroid artery is sometimes doubled, rarely absent, on one side, being replaced by branches of the same artery on the opposite side. There is the lowest thyroid artery, starting directly from the aortic arch.

The lingual artery is variable in its origin. In 55% of cases, it originates from the external carotid artery at the level of the hyoid bone. Very rarely, the lingual artery is absent. In 14-20% of cases, it originates from a common trunk together with the facial artery.

The occipital, posterior auricular and ascending pharyngeal arteries may originate at different levels from the external carotid artery and have different diameters. Each of these arteries may sometimes be absent.

The maxillary artery is variable in terms of its origin and caliber. It often has additional branches (the uppermost pharyngeal artery, etc.).

The superficial temporal artery sometimes doubles, is extremely rarely absent, and often produces additional branches that extend in different directions.

The internal carotid artery is sometimes absent on one side. Rare branches of the internal carotid artery include the pharyngeal artery, occipital, lingual arteries, transverse facial artery, palatine and other arteries. The inferior thyroid artery, accessory inferior thyroid artery, bronchial artery, lateral mammary artery may branch off from the internal carotid artery.

The subclavian artery sometimes passes in the thickness of the anterior scalene muscle. Additional branches to the main bronchus, the inferior thyroid artery (in 10% of cases), the transverse scapular artery, the ascending cervical artery, the superior intercostal artery, the deep cervical artery (in 5% of cases), the accessory vertebral artery, the internal thyroid artery, the inferior accessory thyroid artery, the lateral mammary artery, and often the dorsal scapular artery may branch off from the subclavian artery.

The vertebral artery rarely branches off from the subclavian artery in two trunks, which then join into one. Sometimes one trunk of the vertebral artery branches off from the subclavian artery, and the other from the aortic arch. Very rarely there is an additional (third) vertebral artery branching off from the inferior thyroid artery. Sometimes the vertebral artery enters the canal of the transverse processes at the level of the V, IV, or even II-III cervical vertebrae. The inferior thyroid, superior intercostal, and deep cervical arteries occasionally branch off from the vertebral artery. The inferior posterior cerebellar artery is often absent.

The thyrocervical trunk often gives off the transverse artery of the neck. Rarely, the vertebral artery, medial artery of the mammary gland (in 5% of cases), deep artery of the neck, superior intercostal artery, internal thyroid artery branch off from it. The ascending cervical artery is often very thin, begins with a short common trunk together with the superficial cervical artery. The costocervical trunk is often absent.

The transverse artery of the neck is often absent, often originating directly from the subclavian artery. The branches of the transverse artery of the neck can be the medial thyroid and deep cervical arteries.

The number of branches of the axillary artery and their topography are variable. The posterior circumflex humeral artery often branches off together with the deep brachial artery. The anterior and posterior circumflex humeral arteries often branch off from the axillary artery together. The lateral thoracic and thoracospinal arteries can branch off with 3-4 trunks each, sometimes one of these arteries is absent. The following additional branches of the axillary artery are known: transverse scapular artery, superior collateral ulnar artery, deep brachial artery, radial artery.

The brachial artery rarely divides into the radial and ulnar arteries very low (on the forearm), in 8% of cases - unusually high. In 6% of cases, the axillary artery, rather than the brachial artery, divides into the radial and ulnar arteries; in these cases, the brachial artery is absent. Sometimes there is an additional branch of the brachial artery - the superficial middle artery of the forearm. The upper and lower collateral ulnar arteries may be absent, each of them is variable in the degree of expression, topography. The subscapular artery, the anterior and posterior arteries that circumflex the humerus (separately or both together), the accessory radial collateral artery, and the accessory deep artery of the arm rarely branch off from the brachial artery.

The radial artery is extremely rarely absent or located more superficially than normal. Sometimes the radial artery reaches only the middle of the forearm, more often it exceeds the ulnar artery in diameter. The right dorsal artery of the index finger sometimes branches off from the radial artery.

The ulnar artery is sometimes located directly on the fascia of the forearm, subcutaneously. The accessory recurrent ulnar artery, interosseous recurrent artery, middle ulnar artery, accessory interosseous artery, median artery, first and second common palmar digital arteries sometimes branch off from the ulnar artery as additional branches. With a high division of the brachial artery, the interosseous anterior artery (a branch of the common interosseous artery) is sometimes absent.

The variants of the arteries of the hand are numerous. They appear as different combinations of arteries that make up the superficial and deep arterial arches. The most common variants of the arteries of the hand are the following:

1. the superficial palmar arch is absent. The common palmar digital arteries to the eminence of the thumb and the index (sometimes middle) finger come directly from the palmar branch of the radial artery. The branches to the other fingers come from the arcuate ulnar artery. The deep palmar arch is usually poorly expressed;
2. the superficial palmar arch is very thin, the deep palmar arch is well expressed. The branches of the superficial palmar arch supply blood to the III and IV fingers, the rest are supplied by the deep palmar arch;
3. the superficial palmar arch is well defined, the end of the radial artery and the deep palmar arch are very thin. The common palmar digital arteries extend from the superficial arch to all fingers;
4. The superficial palmar arch is doubled. From the palmar superficial branch of the radial artery, the common palmar digital arteries branch off to the II-IV fingers, and to the remaining fingers - from the deep palmar arch.

The thoracic aorta often gives off inconstant branches: the superior intercostal, right renal, and lower right bronchial arteries. Very rarely, the right subclavian artery branches off from the thoracic aorta. The esophageal and mediastinal branches of the thoracic aorta vary in number and position, and the posterior intercostal arteries vary in number. Sometimes one intercostal artery supplies two or three adjacent intercostal spaces. The lower two intercostal arteries may begin with a common trunk. Sometimes, the bronchial artery branches off from the third posterior intercostal artery.

The abdominal part of the aorta may give off an additional left gastric artery (a common variant), additional hepatic, additional splenic, and additional inferior phrenic arteries. The superior pancreatic artery, inferior suprarenal, and additional testicular (ovarian) arteries may branch off from the abdominal part of the aorta. The number of lumbar arteries varies (from 2 to 8). An additional median sacral artery is sometimes encountered. An additional renal artery, inferior epigastric artery, and right external iliac artery sometimes branch off from the area of the aortic bifurcation.

The celiac trunk may be absent, its branches depart from the aorta independently. Sometimes the celiac trunk divides into the common hepatic and splenic arteries. Additional branches of the celiac trunk may be the superior mesenteric, accessory splenic arteries, and superior pancreatic artery. The inferior phrenic artery, a branch to the left lobe of the liver, and an accessory artery to the spleen sometimes depart from the left gastric artery. The common hepatic artery is rarely absent, may be very thin, and sometimes originates from the superior mesenteric artery. The common hepatic artery may give a marginal branch to the caudate lobe of the liver, branches to the pylorus, inferior phrenic artery, left gastric artery, accessory artery of the gallbladder, and accessory splenic artery. The gastroduodenal artery sometimes gives off the left hepatic branch or the right gastric artery. The right hepatic branch of the proper hepatic artery in 10% of cases is located in front of the hepatic duct rather than behind it. The splenic artery is sometimes doubled, and the left gastric, middle colic, and proper hepatic arteries can branch off from it.

The non-permanent branches of the superior mesenteric artery are the proper hepatic artery (very rare), its left branch, 1-2 gallbladder arteries, the splenic, gastrosplenic or right (rarely left) gastroepiploic arteries, and the right gastric artery. Sometimes an additional middle colic artery branches off from the anterior semicircle of the superior mesenteric artery.

The inferior mesenteric artery is variable in the level of its origin, sometimes absent. An additional middle colic, additional hepatic, additional rectal, and vaginal arteries may branch off from it. The junction of the inferior mesenteric and middle colic arteries (Riolan's arch) is often absent.

The middle adrenal artery originates from the testicular artery (usually on the right). The right and left testicular (ovarian) arteries can originate from the aorta by a common trunk. Rarely, the testicular (ovarian) arteries are doubled on one or both sides. Sometimes they originate from the renal or middle adrenal artery.

Renal arteries often branch off above or below their usual position, their number can be up to 3-5. Additional renal arteries branch off from the inferior mesenteric or common iliac artery. The inferior phrenic, proper hepatic, jejunal and ileal arteries, middle adrenal, testicular (ovarian) arteries, branches to the pancreas, additional inferior adrenal arteries, additional branches to the crura of the diaphragm can branch off from the renal artery.

The common iliac arteries sometimes give off additional mesenteric, renal arteries, 2-4 lumbar, middle sacral, additional renal, iliolumbar, superior lateral sacral, umbilical and obturator arteries.

The external iliac artery is extremely rarely doubled. Its length can be from 0.5 to 14 cm. The inferior epigastric artery may be absent, sometimes doubled, its length varies from 0.5 to 9 cm. The deep circumflex ilium artery is often doubled. Additional branches of the external iliac artery may be the obturator artery (in 1.7% of cases), iliolumbar, superficial epigastric arteries, deep femoral artery, external genital artery.

The internal iliac artery is rarely doubled and may have a tortuous course.

The iliolumbar artery is sometimes doubled, rarely absent. Both lateral sacral arteries may branch off as a common trunk.

The obturator artery gives off additional branches: the iliolumbar artery, accessory hepatic, inferior vesical, vesicoprostatic, uterine, vaginal, dorsal artery of the penis, artery of the bulb of the penis, etc. The obturator artery can branch off from the inferior epigastric artery; in 10% of cases, it is formed from the fusion of two branches branching off from the inferior epigastric and deep artery encircling the ilium (two-root obturator artery).

The superior gluteal artery sometimes begins with a common trunk with the obturator artery or with the inferior rectal artery, uterine or internal pudendal artery. The umbilical artery is rarely absent on one side. The inconstant branches of the umbilical artery are the middle rectal artery, vaginal artery, and accessory inferior rectal artery. Accessory branches of the inferior vesical artery may be the accessory internal pudendal and prostatic arteries. The middle rectal and azygos vaginal artery may branch off from the uterine artery.

The internal pudendal artery often begins together with the inferior gluteal artery, sometimes with the obturator, umbilical or inferior vesical artery. The following may be inconstant branches of the internal pudendal artery: the inferior vesical artery, the middle rectal artery, the uterine artery, the prostate artery, and the sciatic nerve artery.

The internal thoracic artery is sometimes duplicated. The femoral artery may branch off into the iliac lumbar artery, rarely the dorsal artery of the penis, the inferior epigastric artery (in 8% of cases), (obturator in 2% of cases), accessory superficial epigastric artery, perforating arteries, saphenous artery of the thigh, as well as the anterior (in 11% of cases) and posterior (in 22% of cases) arteries that circumflex the femur. The external genital arteries are sometimes absent, being replaced by branches of the deep femoral artery.

The deep femoral artery sometimes begins unusually high, directly under the inguinal ligament, or lower than usual. Rarely, the deep femoral artery originates from the external iliac artery. The inferior epigastric artery (in 0.5% of cases), obturator artery, dorsal artery of the penis, superficial epigastric and other arteries may additionally branch off from the deep femoral artery. The medial circumflex femoral artery sometimes begins with a common trunk with the obturator artery.

The popliteal artery is very rarely doubled over a short distance. Its additional branches are: the peroneal artery, the accessory posterior tibial artery, the recurrent posterior tibial artery, and the small saphenous artery. In 6% of cases, the middle artery of the knee originates from the superior lateral and medial arteries of the knee.

The anterior tibial artery is sometimes very thin, ending above the lateral malleolus with a connection with a branch of the peroneal artery. Additional branches of the anterior tibial artery may be the middle artery of the knee, the common peroneal artery, additional lateral arteries of the tarsus, and the medial artery of the tarsus.

The posterior tibial artery is rarely absent. In 5% of cases, it is very thin and reaches only the middle third of the leg. Additional branches of the posterior tibial artery may be the accessory peroneal artery, the great saphenous artery (accompanying the vein of the same name on the leg). The peroneal artery is absent in 1.5% of cases.

Variations of the arteries of the foot are rarer than those of the arteries of the hand; most of them are caused by a change in position, the presence of additional or absence of the main branches of the anterior and posterior tibial arteries, the peroneal artery, and their branches.