The posterior cerebral circulation (or simply, posterior circulation) is the blood supply to the posterior portion of the brain, including the occipital lobes, cerebellum and brainstem.
The posterior circulation is supplied by the vertebral arteries that combine to form the basilar artery which...
The posterior choroidal artery is not in fact a single artery, although it is commonly referred to as such. The posterior choroidal arteries, often numbering up to 10 or 11 per hemisphere, are divided into medial posterior choroidal artery and lateral posterior choroidal artery groups. They usua...
Posterior choroidal artery occlusion uncommonly presents as an isolated stroke syndrome. It usually coexists with posterior cerebral artery and often superior cerebellar artery involvement.
When seen in isolation damage is characteristically limited to the:
lateral geniculate body
The posterior communicating artery (PCOM or P Comm) makes up the posterior linkage in the circle of Willis.
The PCOM originates from the posterior aspect of the C7 (communicating) segment of the internal carotid artery and extends posteriormedially to anastomose with the ...
The posterior ethmoidal artery is a branch of the ophthalmic artery. It supplies the posterior ethmoidal sinuses, dura and nasal cavity.
It passes through the posterior ethmoidal foramen to enter the anterior cranial fossa where it gives off meningeal and nasal branches.
The posterior external jugular vein is a tributary of the external jugular vein.
Origin and course
Forms from the confluence of several superficial veins in the posterosuperior neck and posterior scalp. It passes superficially over the posterior triangle to drain into the extern...
The posterior humeral circumflex artery is a vessel arising from the axillary artery at the proximal part of the arm.
origin: branch of the axillary artery at the proximal part of the arm 1
location: proximal arm
supply: glenohumeral joint, teres major and minor, and deltoid 1
Posterior inferior cerebellar artery (PICA) is one of the three vessels that provide arterial supply to the cerebellum. It is the most variable and tortuous cerebellar artery.
Its origin is highly variable:
~20% arise extracranially, inferior to the foramen magnum
The intercostal spaces are supplied by pairs of anterior and posterior intercostal arteries.
The first two intercostal spaces are supplied by the superior intercostal artery, and the remaining nine are supplied by separate branches from the descending thoracic aorta 1. The right ...
The posterior interosseous artery is one of the two terminal branches of the short common interosseous artery (from the ulnar artery). The artery courses deep in the proximal anterior compartment of the forearm to pierce the upper aspect of the interosseous membrane and enter the posterior compa...
The posterior spinal arteries are a pair of arteries that supply the respective ipsilateral grey and white posterior columns of the spinal cord.
The posterior spinal arteries arise from either the posterior inferior cerebellar or vertebral arteries (V3 or V4 segments) and runs t...
The posterior tibial artery (PTA) is one of the 2 branches of the tibioperoneal trunk in the lower leg and provides oxygenated blood to the posterior compartments of the leg and plantar surface of the foot. It is accompanied by the posterior tibial vein, along its course.
The posterior tibial veins accompany the posterior tibial artery. They receive tributaries from the calf muscles (especially from the venous plexus in the soleus) and from superficial veins. They join the anterior tibial veins to form the popliteal vein and enter the popliteal fossa.
The posterior ulnar recurrent artery is a recurrent branch of the proximal ulnar artery that ascends in the posterior medial aspect of the elbow, posterior to the medial epicondyle of the humerus to anastomose with the superior ulnar collateral artery (from the brachial artery) and contribute to...
The posterior vein of the left ventricle is a vein of the heart which courses over the inferior wall of the left ventricle and drains into the coronary sinus to the left of where the middle cardiac vein drains into the sinus. It drains, not unsurprisingly, the inferior wall of the left ventricle.
Post thrombotic syndrome (PTS) is a syndrome of chronic venous insufficiency following deep vein thrombosis due to valvular incompetence which results in chronic reflux and chronic venous hypertension.
PTS is a common complication following extensive DVT of the limbs. Up to half o...
Power Doppler is a technique that uses the amplitude of Doppler signal to detect moving matter. Power Doppler:
is independent of velocity and direction of flow, so there is no possibility of signal aliasing
is independent of angle, allowing detection of smaller velocities than colour Doppler, ...
The primitive arteries in the brain can be remembered by the following mnemonic:
P: posterior inferior cerebellar (PICA)
A: anterior choroidal
The meningohypophyseal trunk and anterior choroidal and posterior ...
The princeps pollicis artery (also known as the first palmar metacarpal artery) is a branch of the radial artery that supplies the thumb (1st digit). It arises from the radial artery just as it enters the palm and courses distally along the palmar aspect of 1st metacarpal. At the 1st metacarpoph...
The proatlantal artery is one of the persistent carotid-vertebrobasilar anastomoses, and can be subdivided into two types depending on its origin:
type I: (~55%)
also known as the proatlantal intersegmental artery
arises from the internal carotid artery
corresponds to the first segmental art...
The profunda femoris artery (also known as the deep femoral artery or deep artery of thigh) is a branch of the common femoral artery and is responsible for providing oxygenated blood to the deep structures of the thigh, including the femora.
origin: common femoral artery
A mnemonic to remember the branches of the profunda femoris artery:
Put My Leg Down Please
P: profunda femoris (deep femoral artery)
M: medial circumflex femoral artery
L: lateral circumflex femoral artery
D: descending branch of the lateral circumflex femoral artery
Prostatic artery embolisation (PAE) is a minimally invasive procedure option utilised to treat the benign prostatic hyperplasia (BPH).
PAE has been used for controlling prostatic haemorrhage (such as those associated prostate cancer) since 1970. However, its use in the treatment o...
Proteus syndrome is a rare congenital, multisystemic, hamartomatous condition characterised by asymmetrical overgrowth of almost any part of the body and a broad spectrum of manifestations. It can affect tissue from any germinal layer. It is suspected to be a genetic condition, but a particular ...
The proximal brachial artery represents the initial portion of the brachial artery as it arises as a continuation of the axillary artery at the inferior edge of teres major.
There is no anatomic difference between the proximal and more distal brachial artery. However, the functional response to...
Pseudocoarctation of the aorta is a very rare anomaly characterised by kinking or buckling of the descending aorta at the level of the ligamentum arteriosum without a pressure gradient across the lesion.
It is thought to be of congenital origin, and characterised by elongation and ki...
The pseudovein sign can occur with active gastrointestinal bleeding where contrast extravasation during angiography may have a curvilinear appearance as it pools in the gastric rugae or mucosal folds of bowel, mimicking the appearance of a vein. However, contrast in the “pseudovein” persists bey...
Pseudoxanthoma elasticum (PXE), also known as Grönblad–Strandberg syndrome, is a systemic condition characterised by the degeneration of elastic fibres. It has multiorgan manifestations.
Its prevalence is estimated to be around 1 in 25,000 9.
Patients may ...
The puff of smoke sign describes the characteristic angiographic appearance of tiny abnormal intracranial collateral vessel networks in moyamoya disease. Progressive narrowing of the supraclinoid internal carotid arteries and circle of Willis vessels results in extensive small collateral arteria...
Pulmonary arterial aneurysms refer to a focal dilatation of the pulmonary arterial system.
Overall it is considered a rare entity with autopsy prevalence rates of around 1 in 14,000 to 100,000 4-5.
A true pulmonary artery aneurysm results from dilatation of all three l...
Pulmonary artery atherosclerosis is less common than systemic arterial atherosclerosis in the thorax.
It has been shown to correlate with the following factors
right ventricular dilatation
right ventricular hypertrophy
Pulmonary arterial calcification is the phenomenon which is usually seen in the setting of advanced pulmonary hypertension. It can however be uncommonly present in those without pulmonary hypertension.
The general mechanism in the vast majority is thought to be from high end pulmonar...
Pulmonary arterial dissection is extremely rare but can be a fatal situation. Only a handful of cases have been described in live patients.
It is mostly described in those with chronic pulmonary arterial hypertension.
It can progress to a pulmonary artery aneurysm and fatal spontan...
Pulmonary arteriovenous malformations (PAVM's) are rare vascular anomalies of the lung, in which abnormally dilated vessels provide a right-to-left shunt between the pulmonary artery and vein. They are generally considered direct high flow, low-resistance fistulous connections between the pulmon...
Pulmonary artery atresia (or sometimes known as pulmonary atresia) is one of congenital cardiovascular anomaly in which there is complete disruption between the right ventricular outflow tract (RVOT) and the pulmonary trunk.
The estimated incidence is 1 in 10,000 births.
Pulmonary artery banding is a palliative surgical procedure used to decrease excessive pulmonary blood flow. It is usually used for neonates and infants with left-to-right shunts unable to withstand complete surgical correction.
Some indications include:
Pulmonary artery sarcomas are extremely rare tumours that originate from the intimal mesenchymal cells of the pulmonary artery. It is frequently misdiagnosed as pulmonary thromboembolism.
Primary malignant tumours of the pulmonary arteries are very rare with an incidence of 0.00...
A pulmonary arterial stenosis can be classified into several types 1,2:
type I: involving main pulmonary artery
type II: involving bifurcation
type III: multiple peripheral stenoses
type IV: central and peripheral stenoses
congenital pulmonary stenosis
Pulmonary embolism (PE) refers to embolic occlusion of the pulmonary arterial system. The majority of cases result from thrombotic occlusion, and therefore the condition is frequently termed pulmonary thromboembolism which is what this article mainly covers.
Other embolic sources include:
Pulmonary epithelioid haemangioendothelioma is a rare vascular tumor of the lung with low malignant potential.
Rare tumour, with ~50 cases reported. Patient age at presentation ranges from 25-54 years old. Female predilection.
Often asymptomatic and discove...
Pulmonary gas emboli are a specific type of pulmonary emboli.
Presentation can vary dependant on the degree of air emboli where patients with small amount of air can be asymptomatic. Commonly reported clinical manifestations include sudden dyspnoea, chest pain, hypotensi...
Pulmonary hypertension is defined as a resting mean pulmonary arterial pressure of 25 mmHg or greater at right heart catheterisation, which is a haemodynamic feature that is shared by all types of pulmonary hypertension in the Dana Point classification system. A resting mean pulmonary arterial p...
There are numerous causes of pulmonary hypertension, and thus not surprisingly there have been many classification systems.
In 2003, the 3rd World Symposium on PAH met in Venice and produced an updated classification system (this has been further revised in the Dana Point classification of pulm...
Pulmonary hypertension has many causes, and these can be divided in many ways. A simple and systematic approach is to proceed along the cardiopulmonary pulmonary circulation, as causes are found at each site (for a more official classification system see 2003 third world symposium on pulmonary a...
Pulmonary infarction is most commonly caused by pulmonary embolism (PE) in combination with chronic left heart failure.
The demographics of affected patients are older than those of patients with 'simple' pulmonary embolism (PE) as young patients with no comorbidities are usually ...
Pulmonary oedema due to air embolism is one for the uncommon causes of non-cardiogenic pulmonary oedema.
It usually occurs as an iatrogenic complication of an invasive procedure. Rarely, it may also be associated with open or closed chest trauma.
Air may enter into the low-p...
Pulmonary-renal syndromes refer to a group of conditions that can affect the lung and kidneys. These conditions are typically characterised by diffuse alveolar haemorrhage and glomerulonephritis.
Diseases that can result in a pulmonary-renal syndrome includes:
certain pulmonary vasculitides
The pulmonary trunk is the solitary arterial output from the right ventricle, transporting deoxygenated blood to the lungs for oxygenation.
It is approximately 50 mm long and 30 mm wide (most authors use 29 mm width as the cut off of normal 1).
It arises as a direct superior co...
Pulmonary vein atresia represents to a spectrum of disorders where the pulmonary veins fail to form to varying degrees.
It can be broadly divided into:
unilateral pulmonary vein atresia
bilateral pulmonary vein atresia - common pulmonary vein atresia
anomalous pulmonary venous drai...
The pulmonary veins drain oxygenated blood from the lungs to the left atrium. A small amount of blood is also drained from the lungs by the bronchial veins
There are typically four pulmonary veins, two draining each lung:
right superior: drains the right upper and middle lobes
Pulmonary vein stenosis refers to a spectrum of conditions characterised by narrowing of the pulmonary veins. It can be congenital or acquired.
primary pulmonary vein stenosis - occurs in children
secondary pulmonary vein stenosis - occurs in adults and usually associated with some identifiabl...
Pulmonary vein thrombosis is a rare but potentially serious condition with a number of underlying possible aetiologies.
Often the signs and symptoms are non-specific and can range from acute (pulmonary infarction) to more insidious (progressive or recurrent pulmonary oede...
The clinical symptom of pulsatile tinnitus can occur from a number of causes. They include
dehiscent jugular bulb
high riding jugular bulb
laterally placed sigmoid sinus
abnormal mastoid emissary veins
aberrant internal carotid ...
Pulsus bisferiens or double pulse refers to a wave pattern where there is the presence of two systolic peaks that can be seen in pressure tracings of the the ascending aorta, the aortic arch, and the carotid artery.
It can occur in patients with
aortic valve pathology: aortic regurgitation wit...
The radial artery is a terminal branch of the brachial artery and arises at the cubital fossa of the forearm. It is one of the two main arteries of the forearm, along with the ulnar artery.
origin: terminal branch of the brachial artery
location: inferior aspect of the cubital fossa
The radial collateral artery is one of the two terminal branches of the deep brachial artery. As it descends in the distal part of the posterior compartment of the arm, it pierces the lateral intermuscular septum and contributes to the arterial anastomosis of the elbow specifically the radial re...
The radialis indicis artery is a branch of the radial artery in the hand that supplies the radial aspect of the index finger (2nd digit). It arises from the radial artery in the plam just after the origin of the princeps pollicis artery. The artery courses distally along the radial (lateral) pal...
The radial recurrent artery is the largest lateral branch of the radial artery in the forearm, arising just after its origin. It courses proximally on supinator from its origin to form an arterial arcade with the anterior branch (radial collateral artery) of the profunda brachii (deep brachial) ...
The radial vein is one of the two major deep veins of the forearm, along with the ulnar vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the radial artery and anastomose freely with each other.
It forms in the hand from the ...
Radiation-induced cerebral vasculopathy encompasses a complex and broad range of effects on the intra- and extracranial vessels resulting from injury from radiation exposure.
Clinical symptoms are broad and depend on the underlying vasculopathy. Radiation-induced telangie...
The ramus intermedius is a variant coronary artery resulting from trifurcation of the left main coronary artery 1. It is present in ~20% (range 15-30%) 2-3 of the population.
It can have a course similar to the obtuse marginal branches of the left circumflex artery or the diagonal branches of t...
The Rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolemic, cardiogenic, obstructive and...
Rasmussen aneurysm (not to be confused with Rasmussen encephalitis) is an uncommon complication of pulmonary tuberculosis and represents a pulmonary artery aneurysm adjacent or within a tuberculous cavity.
It can be present in up to 5% of patients with chronic cavitary tuberculos...
The Rastelli procedure is a surgical procedure to correct certain combinations of cardiovascular defects in patients with cyanotic congenital heart disease.
The operation is based on a redirection of ventricular outflows using an intracardiac baffle that tunnels the left ventricle to...
The Raymond–Roy occlusion classification (RROC) is an angiographic classification scheme for grading the occlusion of endovascularly treated intracranial aneurysms 1. It is also known as the Raymond class, Montreal scale or the Raymond Montreal scale.
class I: complete obliteration
class II: r...
Raynaud phenomenon describes a localised vasculopathy whereby there is an exaggerated vascular response to cold temperature or emotional stresses.
Raynaud phenomenon is classified as being either 'primary' or idiopathic, or 'secondary' to another underlying condition (as discussed ...
Recurrent artery of Heubner, also known as the medial striate artery or long central artery, is the largest perforating branch from the proximal anterior cerebral artery (ACA), and is the only one routinely seen on angiography.
Origin and course
Its origin is near the A1-ACOM-A2...
Posterior tibial recurrent artery
Origin and course
Inconstant branch that arises before the anterior tibial reaches the extensor compartment
Ascends anterior to popliteus with the recurrent nerve to that muscle, anastomosing with the inferior genicular branches of the popliteal artery
Renal arterial cut-off sign, as the name suggests, is an abrupt termination of the contrast-opacified lumen of the renal artery. It may or may not be associated with contrast extravasation.
It is seen in a vascular injury, e.g. segmental or main renal artery thrombosis or occlusion.
The renal arterial resistive index (RI) is a sonographic index to assess for renal arterial disease.
It is measured as
RI = (peak systolic velocity - end diastolic velocity ) / peak systolic velocity
the normal value is ≈ 0.60
with 0.70 being around the upper limits of normal
Renal arteriovenous fistulae (AVFs) are anomalous direct communications between arteries and veins in the kidney, which may be confused with a renal arteriovenous malformation (AVM).
The incidence of renal AVF is variable, estimated at 0.3-19% in native kidneys and 6-8% in ren...
Renal arteriovenous malformations (renal AVMs) are an uncommon vascular anomaly, which may be confused with a renal arteriovenous fistula (renal AVF).
Like arteriovenous malformations elsewhere in the body, a renal AVM is formed by a connection between the arterial and venous structu...
The renal arteries originate from the abdominal aorta and enter the renal hila to supply the kidneys. Any variant in arterial supply is important to clinicians undertaking surgery or other interventional renal procedures.
They arise from the abdominal aorta at the L1-2 ...
Renal artery aneurysms (RAA) are considered the second most common visceral aneurysm (15-22%), most common being splenic artery aneurysm (60%). They are more common in females. Most of the lesions are saccular and tend to occur at the bifurcation of main renal artery.
RAAs occur i...
Renal artery dissection may occur as a result of the following processes 1:
aortic dissection extending to involve the renal artery
iatrogenic (e.g. catheterisation)
Renal artery occlusion can happen acutely due to in-situ thrombus, embolism, or dissection. Unless immediately treated, it can lead to renal infarction 1.
The condition is more common in the elderly, however, it may be seen in a younger age group if they have risk factors (describ...
Renal artery pseudoaneurysms are uncommon vascular finding, with the majority occuring after a renal intervention.
A renal artery pseudoaneurysm differs from a renal artery true aneurysm (as might occur in fibromuscular dysplasia) in that it does not involve all three layers of the a...
Renal artery stenosis (RAS) refers to a narrowing of a renal artery. When the process occurs slowly, it leads to secondary hypertension. Acute renal artery stenosis does not lead to hypersecretion of renin.
When the stenosis occurs slowly, collateral vessels form and supply the kidne...
Renal infarction results from interruption of the normal blood supply to part of, or to the whole kidney. The main imaging differential diagnosis includes pyelonephritis and renal tumours.
The demographics of affected patients will depend on the underlying cause, although as most ...
Renal sympathetic denervation (RSDN), also known as renal denervation, is an interventional procedure that uses radiofrequency ablation to destroy the nerve endings in the wall of the renal arteries. Endovascular (trans-catheter) techniques are an alternative to surgical sympathectomy.
Renal vascular pedicle injury is a severe form of renal trauma, which if not recognised and treated expediently with lead to the loss of the kidney.
Contrast enhanced CT is the Imaging modality of choice. On CT it is recognised as a non-enhaning kidney. Perirenal ha...
The renal veins are asymmetric paired veins that drain the kidneys.
The renal vein is formed by the union of two-to-three renal parenchymal veins in the renal sinus. It emerges from the renal hilum anterior to the renal artery and drains into the inferior vena cava at th...
There are several variations in renal venous anatomy. Some of these are specific to the left renal vein.
Left renal vein anomalies are generally classified into four types 2:
the ventral pre-aortic limb of the left renal vein is obliterated, but the dorsal retro-aortic limb persists a...
Renal vein thrombosis can be either from "bland" thrombus or tumour thrombus (extension of tumor into the vein). There are numerous aetiologies for bland thrombus, but it most commonly occurs in the hypercoagulable nephrotic syndrome. Renal vein thrombus is commoner on the left side, presumably ...
Renal vein varices develop for various reasons and are usually asymptomatic.
Renal vein varices are usually asymptomatic. Some patients may present with flank pain and/or haematuria.
chronic renal vein thrombosis
Renovascular hypertension (RVH) is a type of secondary hypertension, where high blood pressure develops secondary to renal artery disease.
Approximately 2.5% (range 0.5-5%) of hypertensive patients will have RVH as a cause 2,3.
There are a number of condit...
When issuing an MRI or CT report on a patient with an aortic aneurysm, whether it be thoracic or abdominal, a number of features should be mentioned to aid the referring clinician in managing the patient. Reporting tips for aortic aneurysms include 1-2:
size and shape
sac dimensions (outer sur...
Retinal Vasculopathy with Cerebral Leukoencephalopathy and Systemic manifestations (RVCL-S) is an autosomal dominant microvasculopathy of the brain, retina, and other organ systems.
RVCL-S was described by Stam and colleagues in 2016 to encompass several previously described condit...
Retroaortic left renal vein (RLRV) is an anatomical variant where the left renal vein is located between the aorta and the vertebra and drains into the inferior vena cava.
Its recognition is important in order to avoid complications during retroperitoneal surgery or interventional procedures 2....
The retromandibular vein runs through the substance of the parotid gland. It lies deep to the facial nerve and superficial to the external carotid artery. The retromandibular vein is formed, usually within the parotid, by the confluence of the maxillary vein and the superficial temporal vein.
Retroperitoneal fibrosis (RPF), is a condition that has previously been described as chronic periaortitis. It is an uncommon fibrotic reaction in the retroperitoneum that typically presents with ureteric obstruction.
The disease is part of a spectrum of entities that have a common pathogenic pr...
Retroperitoneal haemorrhage can be a source of significant yet occult blood loss.
The clinical features are varied depending on the amount of hemorrhage present, rate of onset and ability of the surrounding structures to contain the hemostatic system. The classical featur...
The reverse figure 3 sign (also known as the E sign) is seen on barium swallows in patients with a coarctation of the aorta and is the medial equivalent of the figure 3 sign seen on plain chest radiographs. It is formed by prestenotic dilatation of the ascending aorta, indentation of the coarcta...