Haemangiomas are benign tumours of vascular origin usually seen in early childhood, divided into
Unfortunately, the term haemangioma has been widely misused to apply to many non-neoplastic vascular malformations, particularly the com...
Haemangiopericytoma is a term formerly used to describe a continuum of mesenchymal tumours with elevated cellularity found throughout the body in soft tissue and bone. After many years of controversy, haemangiopericytomas have been shown to not only share histological features similar to solitar...
Haemangiopericytomas of the spleen are very rare vascular neoplasma with only a few case reports available at the time of writing.
Splenic haemangiopericytomas are typically asymptomatic or can result in splenomegaly.
These are soft tissue vascular neoplasms a...
An acquired arm arteriovenous fistula (AVF) creation is a procedure performed for haemodialysis access in those with end stage renal failure. It connects and artery to a vein in the vein. This can either be a native connection or a connection using a PTFE (polytetrafluoroethylene) graft.
Haemoptysis refers to coughing out blood. Generally, it appears bright red in colour as opposed to blood from gastrointestinal tract which appears dark red. It is considered an alarming sign of a serious underlying aetiology.
Massive haemoptysis is referred to as expectoration of >...
Haemosuccus pancreaticus, also known as pseudohaemobilia or haemoductal pancreatitis, is defined as upper gastrointestinal tract haemorrhage originating from the pancreatic duct into the duodenum via the ampulla of Vater, or major pancreatic papilla.
male:female ratio is 7:1
Hamburg classification system of vascular malformations is one of the more commonly used systems to describe the wide range of vascular malformations, largely replacing the many various eponymous syndromes traditionally used. It accounts for the underlying anatomical, histological, and pathophys...
The hemiazygos vein is the asymmetric counterpart to the azygos vein and forms part of the azygos venous system.
The hemiazygos vein is formed by the confluence of the left ascending lumbar and left subcostal veins.
The hemiazygos vein enters the thorax either ...
The resistive index (RI) is the commonest Doppler parameter used for hepatic arterial evaluation. The usual range in normal, as well as post-transplant individuals, is between 0.55 and 0.8.
It is measured by:
RI = (peak systolic velocity - end diastolic velocity)/peak systolic velocity
The hepatic artery proper or the proper hepatic artery arises from the common hepatic artery as it divides into its two terminal branches, the hepatic artery proper and the gastroduodenal artery.
The hepatic artery proper runs anterior to the portal vein and to the left ...
A hepatic lymphangioma is a rare benign condition that corresponds to focally dilated lymphatic channels in the liver.
Most cases are asymptomatic.
A lymphangioma is a benign lesion that can occur at almost any location in the body. Hepatic involvement is les...
The hepatic veins are three large intraparenchymal veins which drain the liver substance into the inferior vena cava (IVC), named the right hepatic vein, middle hepatic vein and left hepatic vein. The veins are important landmarks, running in between and hence defining the segments of the liver....
Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a condition arising from occlusion of hepatic venules.
right upper quadrant pain
abnormal liver function tests
Toxic injury to liver s...
Hereditary connective tissue diseases are a group of connective tissue disease that have a degree of inheritance risk. They include :
Marfan syndrome - genetic disease causing abnormal fibrillin
Ehlers-Danlos syndrome - progressive deterioration of collagen and affects joints, heart v...
Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterised by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system.
Heyde syndrome is an association between aortic valve stenosis and gastrointestinal haemorrhage.
The aetiology of the gastrointestinal bleeding in this setting is uncertain, but it is thought to be related to intestinal angiodysplasia. The strength of this association independent of age-related...
The high attenuating crescent sign represents an acute haematoma within either the mural thrombus or the aneurysm wall, especially when detected on unenhanced CT scans. It is a specific sign of impending abdominal aortic aneurysm (AAA) rupture or so-called contained rupture.
The walls of arteries and veins are composed of endothelial cells, smooth muscle cells and extracellular matrix (including collagen and elastin). These are arranged into three concentric layers: intima, media and adventitia.
The intima is the inner layer abutting the vessel lumen. The adventit...
The Hoffman-Rigler sign is a sign of left ventricular enlargement inferred from the distance between the inferior vena cava (IVC) and left ventricle (LV).
On a lateral chest radiograph, if the distance between the left ventricular border and the posterior border of IVC e...
Hughes-Stovin syndrome (HSS) is a vasculitis that predominantly affects large vessels. The disease bears some resemblance to Behcet disease.
It predominantly occurs predominantly between the 2nd to 4th decades. There is a recognised male predilection.
The Hunt and Hess scale describes the severity of subarachnoid haemorrhage, and is used as a predictor of survival.
asymptomatic or minimal headache and slight neck stiffness
moderate to severe headache; neck stiffness; no neurologic deficit except cranial nerve...
The hyperdense MCA sign refers to focal increased density of the middle cerebral artery (MCA) on CT and is direct visualisation of thromboembolic material within the lumen. It is thus the earliest visible sign of MCA infarction seen immediately at the time of embolism. It is the longitudinal eq...
Hyperperfusion syndrome after carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare complication.
Hyperperfusion occurs in ~7.5% (range 1-14%) of patients but only a minority (~1.5%) of patients are symptomatic 1,2, with incidence being reported slightly more af...
Hyper-reninaemic hypertension may have many causes including:
renal artery stenosis
renal secreting tumour, e.g. renal cell carcinoma, reninoma
renal compression: large renal mass, subcapsular haemorrhage (Page kidney)
Hypertension refers to an increase in blood pressure above the 'normal' for the age, sex and ethnicity of the patient. This can be specified according to the vascular system involved.
Hypervascular liver lesions may be caused by primary liver pathology or metastatic disease.
hepatocellular carcinoma (HCC)
most common hypervascular primary liver malignancy
early arterial phase enhancement and then rapid wash out
rim enhancement of c...
Hypothenar hammer syndrome occurs from trauma to the distal ulnar artery or proximal portion of superficial palmar arch as a result of repetitive trauma to the hypothenar eminence. Originally described in patients using hammers and screwdrivers, it is also seen in various athletes such as basket...
Idiopathic dilatation of the pulmonary trunk is a rare congenital anomaly comprising of pulmonary trunk enlargement with or without dilatation of the right and left pulmonary arteries.
For this diagnosis, exclusion of pulmonary and cardiac diseases (mainly pulmonary valve stenosis) and confirma...
Idiopathic pauci immune pulmonary capillaritis (IPIPC) is considered a rare type of pulmonary vasculitis. Some authors consider this due be an organ specific subset of microscopic polyangiitis 3. It can result in diffuse alveolar haemorrhage.
It is an isolated small vessel vasculitis...
Idiopathic portal hypertension (noncirrhotic portal hypertension or Banti syndrome) is a term that has been given to portal hypertension occurring without hepatic cirrhosis, parasitic infection, or portal venous thrombosis.
Rare condition. More common in India and Japan.
Idiopathic pulmonary arterial hypertension is uncommon, representing only a tiny fraction of all cases of pulmonary arterial hypertension, which has a very long list of secondary causes (see causes of pulmonary arterial hypertension).
Older terms for this entity include primary pul...
Idiopathic retroperitoneal fibrosis (IRF) is a subtype of retroperitoneal fibrosis where no obvious cause is found. It includes a spectrum of diseases which are characterized by fibroinflammatory tissue encasing the abdominal aorta and the iliac arteries. This process may extend into the retrope...
IgA vasculitis (formally known as Henoch-Schonlein purpura (HSP)) is a type of non-thrombocytopaenic immune-mediated small vessel acute leukocytoclastic vasculitis.
It tends to occur in the paediatric population (peak incidence 3-10 years) 3.
In order to differentiate from other types of vascu...
The ileocolic artery is a branch of the superior mesenteric artery (SMA) that runs obliquely to the ileocaecal junction.
It divides into an ileal branch that supplies the terminal ileum and anastomoses with the terminal SMA and a colic branch that supplies the proximal ascending colon and anast...
Iliac arterial aneurysms are focal dilatations of the iliac artery.
Although the dimensions that define the aneurysm are dependent on the sex of the patient and the portion of the artery involved, a common iliac artery (CIA) with a diameter ≥1.7 cm in males or ≥1.5 cm in females is considered ...
Iliac vein occlusion can be due to the variety of causes including:
catheter dissection injuries
IVC filter insertion
direct tumour invasion
enlarged lymph nodes
Iliofemoral deep vein thrombosis occurs when a thrombus in the iliac vein (common, external or internal) or common femoral vein obstructs the venous outflow from the lower limb leading to marked oedema.
To be added
To be added
To be a...
The iliolumbar artery is one of three branches of the posterior division of the internal iliac artery.
origin: posterior division of the internal iliac artery
supply: ilium, iliacus muscle, psoas major muscle, quadratus lumborum muscle, erector spinae muscle, anterio...
Incomplete double aortic arch is a rare vascular ring anomaly wherein a segment of the minor aortic arch, usually the left, is atretic.
As in the case of other vascular rings, this anomaly can cause 1:
Some patients may reach adulthood with...
The infarct core denotes the part of an acute ischaemic stroke which has already infarcted, or is irrevocably destined to infarct regardless of reperfusion. It is also referred as established infarct and is in distinction from the penumbra which remains potentially salvageable.
The inferior adrenal (suprarenal) artery is one of three adrenal arteries that supplies the adrenal gland.
Ipsilateral renal artery (usually before the terminal division of the renal artery)
The course of the inferior suprarenal artery depends on its origin. Re...
The inferior alveolar artery is a branch of the maxillary artery. It runs with the inferior alveolar nerve as it descends through the infratemporal fossa and enters the mandibular canal and supplies mandibular teeth. In the region of the first premolar it bifurcates into the incisive and mental ...
The inferior epigastric artery arises from the external iliac artery and is an important artery supplying the anterior abdominal wall. If a superficial inferior epigastric artery is present, as seen in about two-thrids of cases, then the inferior epigastric artery is referred to as the deep infe...
The inferior gluteal artery is a branch of the anterior division of the internal iliac artery. It originates in the pelvis and supplies the gluteal region and thigh.
origin: anterior division of the internal iliac artery
location: pelvis, gluteal region, back of thigh
The inferior hypophyseal arterial circle, also known as the inferior capsular arterial rete, is an anastamotic arterial network formed around the base of the pituitary gland by branches from three vessels, themselves branches off the cavernous portion of the carotid artery. They are:
The inferior interventricular artery (also known as the posterior interventricular artery or posterior descending artery, PDA) is an artery that extends along the inferior interventricular sulcus. The artery supplies the posterior third of the interventricular septum through posterior septal per...
The inferior mediastinum is the box-shaped space in the mediastinum below the transthoracic plane of Ludwig between the wedge-shaped superior mediastinum above and the diaphragm and inferior thoracic aperture below. There are no physical structures that divide the superior and inferior mediastin...
The inferior mesenteric artery (IMA) is an anterior branch of the abdominal aorta that supplies the hindgut. It is the smallest of the three anterior branches of the abdominal aorta.
within the mesentery of the hindgut
unpaired vessel from the anterior aspect o...
Inferior mesenteric artery aneurysms are among the rarest of all visceral artery aneurysms.
Aneurysms of the inferior mesenteric artery (IMA) only account for <1% of all visceral artery aneurysms 1,2. These aneurysms are more common in men than in women 3.
The inferior mesenteric vein drains blood from the distal portion of the colon as well as the rectum (i.e. the hindgut).
Origin and course
The inferior mesenteric vein drains the mesenteric arcade of the hindgut (comprising of distal transverse, descending, and sigmoid colon). ...
The inferior pancreaticoduodenal artery is the first branch of the superior mesenteric artery (SMA), though it often arises from the first jejunal branch.
It anastomoses with branches of the superior pancreaticoduodenal artery (from the gastroduodenal artery) and it supplies the head of the pan...
The inferior petrosal sinus is one of the dural venous sinuses. It is often a plexus of venous channels rather than a true sinus and drains blood from the cavernous sinus to the jugular foramen (pars nervosa) or sometimes via a vein which passes through the hypoglossal canal to the suboccipital ...
The inferior phrenic arteries (IPA) are paired branches of the abdominal aorta / coeliac trunk supplying the diaphragm. Their importance lies with the fact that the right IPA is the most common extrahepatic arterial supply of a hepatocellular carcinoma.
origin: abdominal aorta or coel...
The inferior rectal artery is an artery that supplies the lower anal canal including the external anal sphincter.
origin: from internal pudendal artery, just after it enters the pudendal canal
course: runs anteromedially through the ischioanal fossa to reach the deep portion of the ex...
The inferior sagittal sinus is one of the dural venous sinuses and runs along the inferior edge of the falx cerebri. It runs from front to back (same as the superior sagittal sinus) and drains into the straight sinus. It receives tributaries from the falx itself as well as some small veins from ...
The inferior thoracic aperture connects the thorax with the abdomen.
The inferior thoracic aperture is irregular in shape and is more oblique and much larger than the superior thoracic aperture. The diaphragm occupies and closes the inferior thoracic aperture, thereby separating ...
The inferior thyroid artery is a branch of the thyrocervical trunk (85%) or subclavian artery (15%) and ascends to enter the thyroid gland on its posterior surface, as well as supplying both the superior and inferior parathyroid glands 1. The nerve is closely related to the ascending limb of the...
The inferior ulnar collateral artery is a vessel arising from the brachial artery at the distal-most part of the upper arm.
origin: branch of the brachial artery superior to the medial epicondyle 1
location: distal lower arm
supply: brachialis, biceps brachii, and coracobrachialis 1
The inferior vena cava (IVC) drains venous blood from the lower trunk, abdomen, pelvis and lower limbs to the right atrium of the heart.
The IVC is formed by the confluence of the two common iliac veins at the L5 vertebral level. The IVC has a retroperitoneal course within the ab...
Inferior vena caval (IVC) thrombosis is an essential diagnosis while evaluating any neoplastic lesion, or portal hypertension. It is also important to differentiate bland thrombus from tumour thrombus.
Patient can present with many features which include
bilateral pedal oede...
Inferior vena cava (IVC) webs are an uncommon condition characterised by obstruction of the hepatic segment of the inferior vena cava by a membrane or fibrous band. This is often associated with occlusion of one or more of the hepatic veins.
If there is hepatic vein invol...
The inferior vesical artery is a branch of the anterior division of the internal iliac artery.
Some texts state it is only present in males and may be replaced by a vaginal artery in females. Note, the vaginal artery which is most commonly described, is often a branch of the uterine artery.
The inferolateral trunk, along with the meningohypophyseal trunk, is a branch of the C4 segment of the internal carotid artery. It is identified in up to 80% of dissection specimens but is less frequently seen on imaging.
It is also referred to as the artery to the inferior cavernous sinus, ari...
Inflammatory abdominal aortic aneurysm (IAAA) is a variant of abdominal aortic aneurysm (AAA) characterised by inflammatory thickening of the aneurysm wall, perianeurysmal fibrosis and adherence to surrounding structures.
They account for ~5 to 10% of all AAAs.
The infraorbital artery is a branch of the third part of the maxillary artery. It runs through the inferior orbital fissure, orbit, infraorbital canal then the infraorbital foramen. Here it gives off the anterior superior alveolar artery which supplies the anterior teeth and the anterior part of...
An infundibulum (plural: infundibula) is a conical outpouching from an artery (usually intracranial), with a broad base narrowing to an apex from which a vessel originates. The most common location for an infundibulum is the origin of the posterior communicating artery (PCOM) from the supraclino...
Infusothorax is a complication of central venous catheter malposition where the catheter tip is located in the pleural space and the infusion of the fluid collects inadvertantly in the pleural space in the form of a pleural effusion. Longer term complications depend on the fluid being infused.
Innominate artery compression syndrome, also known as brachiocephalic artery compression syndrome, is a rare cause of tracheal stenosis that occurs in the paediatric population.
It can only occur in the presence of an aberrantly positioned thymus that forces the aortic arch or innomi...
The inter-arterial course of the left coronary artery, also known as the malignant course of the left coronary artery, is defined as the origin of the left main or left anterior descending coronary artery from the right coronary sinus of Valsalva with a course between the ascending aorta and the...
Inter-arterial course of the right coronary artery (RCA), also known as a malignant variant, may occur if the right coronary artery has an aberrant origin from the the left coronary sinus. It is an uncommon anomaly with potential risk of cardiac ischaemia.
When the right coronary artery arises ...
The intercavernous sinus (anterior and posterior) are dural venous sinuses and connect the left and right cavernous sinuses, along with the basilar venous plexus. They lie in the anterior and posterior borders of the diaphragma sellae. Additional small venous sinuses in the base of the pituitary...
Internal carotid artery dissection, like arterial dissection elsewhere, is a result of blood entering the media through a tear in the intima 1 and is a common cause of stroke in younger patients.
Dissection may occur at any age, but is a common cause of stroke in young patients (2...
The internal carotid artery segments, according to the Bouthillier classification, can be recalled by the following mnemonic:
C'mon Please Learn Carotid Clinical Organizing Classification
C: cervical segment
P: petrous segment
L: lacerum segment
C: cavernous segment
C: clinoid se...
The internal cerebral veins are paired, paramedian veins which course posteriorly along the roof of the third ventricle, between the two leaves of the velum interpositum.
Each is formed at the foramen of Monro by the confluence of the choroidal vein (draining the choroid plexus o...
The internal iliac artery (also known as the hypogastric artery) is the smaller terminal branch of the common iliac artery. It supplies the pelvic walls, pelvic viscera, external genitalia, perineum, buttock and medial part of the thigh.
The common iliac artery bifurcate...
The internal iliac vein (IIV) represents the union of veins and venous plexuses draining the pelvic viscera, pelvic wall, external genitalia, perineum, buttocks and medial thigh.
Above the greater sciatic notch.
Course and termination
Ascends out of pelvis to meet the...
The internal jugular vein (IJV) is the major venous return from the brain, upper face and neck.
Origin and course
It is formed by the union of inferior petrosal and sigmoid dural venous sinuses in or just distal to the jugular foramen (forming the jugular bulb). It descends in t...
A useful mnemonic to remember the branches of the internal jugular vein is:
Medical Schools Let Fun People In
From inferior to superior:
M: middle thyroid vein
S: superior thyroid vein
L: lingual vein
F: facial vein
P: pharyngeal vein
I: inferior petrosal sinus
The internal palpebral arteries, or medial palpebral arteries, are branches of the ophthalmic artery, with superior and inferior medial palpebral branches arising opposite the trochlear of the superior oblique muscle.
The internal palpebral arteries enter the superior and inferio...
The internal pudendal artery is a branch of the anterior division of the internal iliac artery and is the primary supply of the perineum. It is a larger vessel in males than in females.
origin: anterior division of internal iliac artery
location: pelvis, gluteal region, perineum
The internal thoracic artery (previously called the internal mammary artery) supplies the anterior body wall and its associated structures from the clavicles to the umbilicus.
The internal thoracic artery arises from the first part of the subclavian artery in the base of...
The interosseous recurrent artery is a branch of the posterior interosseous artery just after its origin, within the proximal aspect of the posterior compartment of the forearm. It courses proximally between the lateral epicondyle of the humerus and olecranon of the ulna to anastomose with the m...
Intestinal ischaemia refers to vascular compromise of the bowel which in the acute setting has a very high mortality if not treated expediently. Diagnosis is often straight forward provided appropriate imaging is obtained. The disease can be arbitrarily classified into broad groups according to ...
Intimal hyperplasia is not a true disease, but a physiologic healing response to injury to the blood vessel wall. It is the bane of endovascular intervention and vascular surgery.
When the endothelium is injured, endothelial cells release inflammatory mediators that trigger platelet aggregatio...
Intra-aortic balloon pumps (IABP) are used in the intensive care setting to provide haemodynamic assistance to patients in cardiogenic shock.
Function and physiology
The device is comprised of a catheter introduced via the femoral artery, which extends retrogradely to the proximal descending t...
Intra-atrial course of the right coronary artery is an uncommon anatomic variation in the course of the right coronal artery, usually involving the mid and distal segments, where the vessel partially or completely courses through the right atrial chamber.
It is usually asymptomatic and clinical...
Intracranial arteries have unique structure when compared to extracranial vessels of similar size: see general histology of blood vessels entry.
Proximal larger arteries
The proximal arteries, arising from the internal carotid and vertebral arteries have differing distribution of elastic fiber...
Intracranial arterial variants, of which there are many, are collectively common. Their clinical significance may be variable but knowledge and recognition of these variants is fundamental, especially if surgical or endovascular treatments (e.g. for acute stroke, aneurysms or other vascular path...
Intravenous leiomyomatosis (IVLM) is characterised by the extension into venous channels of histologically benign smooth muscle tumour arising from either the wall of a vessel or from a uterine leiomyoma.
Intravenous leiomyomatosis should not be confused with benign metastasising leiomyoma, in ...
Limb ischaemia is a relatively uncommon, but potentially limb (and life) threatening situation. There are many potential causes.
This is a summary article; we do not have a more in-depth reference article.
are symptoms new?
does exercise trigger pain?
Ischaemic colitis refers to inflammation of the colon secondary to vascular insufficiency and ischaemia. It is sometimes considered under the same spectrum as intestinal ischaemia. The severity and consequences of the disease are highly variable.
Ischaemic bowel is typically a dis...
Ischaemic stroke results from a sudden cessation of adequate amounts of blood reaching parts of the brain. Ischaemic strokes can be divided according to territory affected or mechanism.
Stroke is the second most common cause of morbidity worldwide (after myocardial infarction) and...
Isolated periaortitis is a non-aneurysmal form of chronic periaortitis.
Periaortitis may be a local immune response to antigens like oxidized-low density lipoproteins and ceroid found in the atherosclerotic plaques of the abdominal aorta. The disease tends primarily to involve the va...