A persistent sciatic artery is a rare vascular anomaly where there is the continuation of the internal iliac artery into the thigh through the greater sciatic notch. It may be the dominant artery supplying the leg, in which case the superficial femoral artery may be small.
The persistent stapedial artery (PSA) is an abnormal small vessel arising from the petrous portion of the internal carotid artery and crossing through the middle ear. It results from the failure of regression of the embryonic stapedial artery.
The prevalence is thought to range f...
PHACE syndrome, also known as cutaneous haemangioma–vascular complex syndrome or Pascual-Castroviejo type II syndrome, is a phakomatosis that comprises of:
P: posterior fossa malformations (e.g. Dandy-Walker malformation)
A: arterial anomalies
C: coarctation of the aorta and ...
Phase contrast imaging is an MRI technique that can be used to visualise moving fluid. It is typically used for MR venography as a non-IV-contrast requiring technique.
Spins that are moving in the same direction as a magnetic field gradient develop a phase shift that is proportional to the vel...
Phleboliths are literally "vein stones", and represent calcification within venous structures. They are particularly common in the pelvis where they may mimic ureteric calculi, and are also encountered frequently in venous malformations. There is an association with Maffucci syndrome.
Phlegmasia cerulea dolens (PCD) is an uncommon complication of deep venous thrombosis, which results from extensive thrombotic occlusion of the major and collateral veins of an extremity (usually the legs).
Left leg is more commonly affected than the right 4.
Pinch-off syndrome is a spontaneous catheter fracture, which is seen as a complication of subclavian venous catheterisation.
It is a known complication of central venous catheterisation with a much-reduced incidence in current practice and is generally considered to be rare.
Placental chorioangiomas are benign vascular tumours of placental origin. It is the most common tumour of the placenta and is usually found incidentally.
The estimated incidence is at ~1% of all pregnancies 3.
In most cases, chorioangiomas are asymptomatic,...
Polyarteritis nodosa (PAN) is a systemic inflammatory necrotising vasculitis that involves small to medium sized arteries (larger than arterioles).
Polyarteritis nodosa (PAN) is commoner in males and typically presents around the 5th to 7th decades. Twenty to thirty percent of p...
Polymyalgia rheumatica (PMR) is a common inflammatory condition typically affecting elderly people. It is a multisystem disorder but usually affects the musculoskeletal system.
It can manifest in various ways, which are best discussed in the separate articles below:
polymyalgia rheumatica: mus...
Lung involvement in polymyositis can have a number of manifestations inclusive of that resembling interstitial lung disease (for a general discussion of polymyositis - refer to the parent article).
The frequency of a radiographic parenchymal abnormality ...
The pontine branches are the small arterial branches of the basilar artery that supply the pons and structures adjacent to the pons.
There are usually 3-5 paired arterial branches which are located in the mid-basilar region between the anterior inferior cerebellar artery and the superior cerebe...
The popliteal artery represents the direct continuation of the superficial femoral artery in the popliteal fossa as the vessel courses posteriorly behind the knee.
origin: continuation of the superficial femoral artery
main branch: anterior tibial artery
termination: continues as the...
Popliteal artery aneurysms are the most common peripheral arterial aneurysm and the second most common aneurysm after abdominal aortic aneurysms.
Overall, popliteal artery aneurysms are uncommon. They occur almost exclusively in males (up to 97%) for unknown reasons 8-9. There is ...
Popliteal artery entrapment syndrome (PAES) refers to symptomatic compression or occlusion of the popliteal artery due to a developmentally abnormal positioning of the popliteal artery in relation to its surrounding structures such as with the medial head of gastrocnemius (MHG) or less commonly ...
The popliteal fossa is a diamond or rhomboid-shaped fat-filled space in the posterior knee. The space is extremely dynamic, allowing for its neurovascular contents to move during the extreme range of motion produced by knee flexion and extension.
The popliteal vein forms from the posterior and anterior tibial veins and ascends through the popliteal fossa to the opening in adductor magnus where it becomes the femoral vein.
Its relationship to the popliteal artery changes as the vein ascends, but it is always between the popliteal artery ...
Popliteal venous aneurysms are rare than those of the popliteal artery and are mostly asymptomatic. However, due to the disturbance of the venous blood flow, they can lead to potentially life-threatening consequences, such as deep vein thrombosis (DVT) and pulmonary embolism (PE).
Portal hypertension is defined as portal venous pressure greater than 12 mmHg.
Causes can be split in their relation to the hepatic sinusoids:
portal vein thrombosis
extrinsic compression of portal vein
Schistosomiasis (S. mansoni or S. japonicum)
In portal hypertension, chronic portal venous congestion leads to dilatation and ectasia of the submucosal vessels in the stomach (portal hypertensive gastropathy), small bowel (portal hypertensive enteropathy) and/or large bowel (portal hypertensive colopathy). This may result in upper or lower...
The portal vein (PV) (sometimes referred to as the main or hepatic portal vein) is the main vessel in the portal venous system and drains blood from the gastrointestinal tract and spleen to the liver.
The portal vein usually measures approximately 8 cm in length in adults with a ...
Portal vein calcification is a rare radiologic finding which can be seen in long-standing portal venous hypertension.
Calcium may be deposited in a thrombus or in the wall of the portal vein and is more rarely found in the splenic vein and superior mesenteric vein.
One of the propos...
Portal vein embolisation (PVE) is a technique used to selectively occlude the blood supply to one of the liver lobes, diverting portal blood flow to the other lobe, the future liver remnant (FLR). This diversion will increase the size of the post hepatectomy future liver remnant (FLR) and increa...
Portal vein thrombosis may be seen in a variety of clinical contexts, and when acute can be a life-threatening condition. It is a major cause of non-cirrhotic presinusoidal portal hypertension. Portal vein thrombus may be either bland and/or malignant (i.e. tumour thrombus), and it is a critical...
Portal venous gas is the accumulation of gas in the portal vein and its branches. It needs to be distinguished from pneumobilia, although this is usually not too problematic, when associated findings are taken into account along with the pattern of gas (i.e. peripheral in portal venous gas, cent...
The portal venous system refers to the vessels involved in the drainage of the capillary beds of the GI tract and spleen into the capillary bed of the liver.
Blood flow to the liver is unique in that it receives both oxygenated and deoxygenated blood. As a result, the partial pressure of oxygen...
Portosystemic collateral pathways (also called varices) develop spontaneously via dilatation of pre-existing anastomoses between the portal and systemic venous systems. This facilitates shunting of blood away from the liver into the systemic venous system in portal hypertension, as a means for r...
The portosystemic shunt ratio is a measure performed using ultrasound to quantify the abnormal flow of portal venous blood that is shunted away from the hepatic sinusoidal circulation in the context of a congenital portosystemic shunt 1.
The ratio is determined using the following e...
Post-embolisation syndrome (PES) is one of the commonest side effects of transarterial embolisation and chemoembolisation. It comprises of a constellation of fever, nausea/vomiting, and pain. It usually occurs within the first 72 hours after embolisation (liver lesion or uterine fibroids) and th...
The posterior auricular artery is a branch of the external carotid artery and supplies scalp posterior to the auricle and the auricle itself.
origin: branch of the external carotid artery above digastric and stylohyoid opposite the styloid process
course: ascends beneath the parotid t...
The posterior auricular vein is tributary of the external jugular vein or retromandibular vein.
Origin and course
It arises over the mastoid process of the temporal bone draining the skin behind the ear and courses anteriorly into the parotid gland, draining into the external ju...
The posterior cerebral arteries (PCA) are the terminal branches of the basilar artery and supply the occipital lobes and posteromedial temporal lobes.
origin: terminal branches of the basilar artery
course: from basilar towards occiput
posterior communicating artery
Posterior cerebral artery (PCA) infarcts arise, as the name says, from occlusion of the posterior cerebral artery. It is a type of posterior circulation infarction.
Symptoms include contralateral homonymous hemianopia and quadrantic visual field defects. Because the PCA s...
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 (DVT) 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...
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 pretzel sign is seen on DSA and is indicative of a serpentine aneurysm 1.
The sign refers to the sinusoid configuration of the intra-aneurysmal vascular channel seen in serpentine aneurysms, giving it the appearance of a pretzel.
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...
The prostatic venous plexus is a network of veins around the anterolateral aspect of the prostate and anterior to the bladder. Tributaries include:
deep dorsal vein of the penis
anterior vesical rami
The receipt of blood from the vesical and prostatic rami connect the prostati...
Protein C deficiency is a hypercoagulable state due to reduced activity or an absolute deficiency of protein C, an anticoagulant protein. Protein C deficiency increases the risk of venous thrombosis.
The prevalence of protein C deficiency in the general population is around 1 per ...
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 a 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. A resting mean pulmonary arterial pressure of 20 mmHg or less is considered...
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 one of the key complications of pulmonary embolism (PE).
Pulmonary infarction occurs in the minority (10-15%) of patients with PE 2. Although in a necropsy study of those with lethal PE, 60% of cases developed infarction 7.
Until recently it was felt that...
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 or main pulmonary artery is the solitary arterial output from the right ventricle, transporting deoxygenated blood to the lungs for oxygenation.
The pulmonary trunk is approximately 50 mm long and 30 mm wide (most authors use 29 mm width as the cut-off of norm...
Pulmonary vasculitis refers to vasculitides that affect the lung or pulmonary vessels. If this definition is used, a large group of conditions can fall into this category. The respiratory system may be potentially involved in all systemic vasculitides, although to a variable degree.
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...