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
The pericallosal artery is the distal portion of the anterior cerebral artery (ACA) that courses over the superior surface of the body of the corpus callosum in the pericallosal cistern. It gives off many small branches to the corpus callosum, forming the pericallosal moustache.
Some authors de...
The pericallosal moustache is formed by small branches from the pericallosal arteries and their accompanying veins. These form what appears to be an upturned poorly groomed moustache (not unlike Salvador Dali) and outline the superior surface of the corpus callosum (pericallosal cistern).
The lateral lenticulostriate arteries arise from the proximal middle cerebral artery (MCA), usually from M1 segment, more rarely from the postbifurcation or M2 segment. They supply the lateral portion of the putamen and external capsule as well as the upper internal capsule.
They are longer (al...
The medial lenticulostriate arteries are generally considered to arise from the A1 segment of anterior cerebral artery (ACA), and supply the globus pallidus and medial portion of the putamen 1,3.
They are shorter, thinner and fewer in number than the lateral lenticulostriate arteries, which ar...
The anterior communicating artery (ACom) arises from the anterior cerebral artery and acts as an anastomosis between the left and right anterior cerebral circulation. Approximately 4 mm in length, it demarcates the junction between the A1 and A2 segments of the anterior cerebral artery.
The anterior cerebral artery (ACA) along with the middle cerebral artery (MCA) forms at the termination of the internal carotid artery (ICA). It is the smaller of the two, and arches anteromedially to pass anterior to the genu of the corpus callosum, dividing as it does so into its two major bra...
The common carotid artery is a paired artery of the neck that supplies blood to the head, face and neck.
left: branch of the aortic arch
right: branch of the brachiocephalic trunk
course: posterior to sternoclavicular joint, lateral to thyroid and trachea
supply: head and ...
The persistent carotid-vertebrobasilar anastomoses are variant anatomical arterial communications between the anterior and posterior circulations due to abnormal embryological development of the vertebrobasilar system. They are named, with the exception of the proatlantal artery, using the crani...
The ophthalmic artery is a branch of the supraclinoid (C6) segment of the internal carotid artery.
The ophthalmic artery arises medial to the anterior clinoid process as the internal carotid artery exits the cavernous sinus. It originates from the antero- or supero-medial...
The superior hypophyseal artery (or arteries) is a branch from the C6 segment of the internal carotid artery. It is usually a single trunk arising from the medial or posteromedial aspect of the internal carotid artery within 5 mm of the origin of the ophthalmic artery 2. The trunk then divides i...
The caroticotympanic branch (tympanic branch) is a small branch from the C2 segment of the internal carotid artery. It is a vestigial remnant of the hyoid artery.
It passes posterolaterally into the middle ear cavity and anastomoses with the inferior tympanic artery (a branch of the ascending p...
Intracranial arteries have a 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 fib...
There are two arteries passing through Vidian canal from the pterygopalatine fossa to the petrous portion of the ICA. One is a branch of the internal maxillary artery (itself a branch of the ECA) and the other is from the C2 segment of the ICA. It therefore forms one of the ICA to ECA anastamoses.
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...
Alain Bouthillier et al. described a seven segment internal carotid artery classification system in 1996 1. It remains the most widely used system for describing the internal carotid artery segments.
A helpful mnemonic for remembering ICA segments is:
C'mon Please Learn Carotid Clinical Organ...
The inferior hypophyseal arterial circle, also known as the inferior capsular arterial rete, is an anastomotic 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 meningohypophyseal trunk, also known as the posterior trunk, is a branch of the C4 (cavernous) segment of the internal carotid artery. In contrast to the inferolateral trunk, it is almost always identified at autopsy. However, due to its small size, the meningohypophyseal trunk is seen only ...
Lower gastrointestinal bleeding usually occurs distal to the ligament of Treitz, and has a wide differential diagnosis:
The superior anastomotic vein (or vein of Trolard) is the largest superficial vein on the lateral surface of the parietal or frontal lobe that connects the superior sagittal sinus and the superficial middle cerebral vein (of Sylvius). It usually runs in the post-central sulcus draining the adjac...
The inferior anastomotic vein, also known as vein of Labbé, is part of the superficial venous system of the brain.
It is the largest venous channel on the lateral surface of the brain that crosses the temporal lobe between the Sylvian fissure and the transverse sinus. It courses posteroinferio...
An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz.
Upper gastrointestinal bleeding (UGIB) is defined as bleeding proximal to the ligament of Treitz.
The incidence of acute upper GI bleeding is ~100 per 100,000 adults per year. Upper GI bleeding is twice as common in men as in women and increases in prevalence with age 5. The demog...
Endotension, also referred to as a type V endoleak, is not a true leak but is defined as continued expansion of the aneurysm sac greater than 5 mm, without radiographic evidence of a leak site.
It is a poorly understood phenomenon but thought to be formation of a transudate due to ul...
The buccinator artery is a small branch from the second part of the maxillary artery. It runs obliquely forward, between the medial pterygoid and the insertion of the temporalis, to the outer surface of the buccinator, to which it is distributed, anastomosing with branches of the facial artery a...
The masseteric artery is a small branch from the second part of the maxillary artery. It passes laterally through the mandibular notch to the deep surface of the masseter muscle. It supplies the muscle, and anastomoses with the masseteric branches of the external maxillary and with the transvers...
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...
The mental artery is a terminal branch of the inferior alveolar artery which itself is a branch of the first part of the maxillary artery. It emerges onto the face from the mandibular canal with the mental nerve at the mental foramen, and supplies muscles and skin in the chin region. The mental ...
The (internal) maxillary artery is the larger of the two terminal branches of the external carotid artery.
Origin and course
The maxillary artery's origin is behind the neck of the mandible, at first, it is embedded in the substance of the parotid gland. From there it passes anterior between ...
Inflammatory abdominal aortic aneurysm (IAAA) is a variant of abdominal aortic aneurysm (AAA) characterized by inflammatory thickening of the aneurysm wall, perianeurysmal fibrosis, and adherence to surrounding structures.
They account for ~5 to 10% of all AAAs.
Varicocele embolization is a minimally invasive method of treating varicoceles by embolizing the testicular vein (internal spermatic veins).
failed surgical ligation
Relative contraindications include:
The occipital artery, a posterior branch of the external carotid artery, opposite the facial artery, near the lower margin of the posterior belly of the digastic muscle, and ends in the posterior part of the scalp.
origin: branch of the external carotid artery at the level of the poste...
The external carotid artery (ECA) is one of the two terminal branches of the common carotid artery that has many branches that supplies the structures of the neck, face and head. The other terminal branch is the internal carotid (ICA), which is somewhat larger than the ECA, which supplies the in...
Varicocele is the dilatation of the pampiniform plexus of veins, a network of many small veins found in the male spermatic cord. It is the most frequently encountered mass of the spermatic cord.
The estimated incidence is at ~15% of the general male population and ~40% of subferti...
Carotid body tumor, also known as a chemodectoma or carotid body paraganglioma, is a highly vascular glomus tumor that arises from the paraganglion cells of the carotid body. It is located at the carotid bifurcation with characteristic splaying of the ICA and ECA.
Cerebral vasospasm following subarachnoid hemorrhage is a major complication of subarachnoid hemorrhage (SAH). It is overtaking rebleed as the major cause of mortality and morbidity in the subgroup of patients with SAH who reach the hospital and receive medical care. It usually occurs after a fe...
Call-Fleming syndrome, also called Call syndrome, essentially synonymous with the more current term reversible cerebral vasoconstriction syndrome (RCVS), although it is felt to be a subset of the former by some, representing the idiopathic RCVS.
Call-Flemming syndrome is therefore characterize...
The internal carotid artery (ICA) is one of the two terminal branches of the common carotid artery (CCA) which supplies the intracranial structures. The other terminal branch is the external carotid artery (ECA), which is somewhat larger in caliber than the ICA, and gifts of several branches to ...
The middle cerebral artery (MCA) is one of the three major paired arteries that supply blood to the brain. The MCA arises from the internal carotid artery as the larger of the two main terminal branches (the other being the anterior cerebral artery), coursing laterally into the lateral sulcus wh...
The basilar artery is part of the posterior cerebral circulation. It arises from the confluence of the left and right vertebral arteries at the base of the pons as they rise towards the base of the brain.
origin: vertebral artery confluence
course: ventral to pons in the pontine ciste...
Deep cerebral vein thrombosis is a subset of cerebral venous thrombosis involving the internal cerebral veins, often coexisting with cortical vein thrombosis or dural venous sinus thrombosis, and with different clinical presentations relying on which segment is involved.
As such please refer to...
The empty delta sign is a CT sign of dural venous sinus thrombosis of the superior sagittal sinus, where contrast outlines a triangular filling defect, which represents thrombus. It is only described in contrast-enhanced CT, not in unenhanced scans.
An equivalent appearance can be noted in the ...
Cerebral venous thrombosis (CVT) (plural: thromboses) refers to the occlusion of venous channels in the cranial cavity, including dural venous thrombosis, cortical vein thrombosis and deep cerebral vein thrombosis. They often co-exist and the clinical presentation among them is very similar and ...
Reversible cerebral vasoconstriction syndrome (RCVS) is a group of conditions with a common clinical and radiologic presentation. It is characterized by thunderclap headache and reversible vasoconstriction of the cerebral arteries.
Numerous and varied terms have been used to descri...
Dural arteriovenous fistulas (dAVF) are a heterogeneous collection of conditions that share arteriovenous shunts from dural vessels. They present variably with hemorrhage or venous hypertension and can be challenging to treat.
Most dural arteriovenous fistulas present in adulthood...
Endovascular aneurysm repair (EVAR) was first pioneered in the early 1990s. Since then the technology of the devices has rapidly progressed and EVAR is now widely used as a treatment of thoracic and abdominal aortic aneurysms (AAA).
The advantages of endovascular repair over open repair are tha...
Endoleaks are characterized by persistent blood flow within the aneurysm sac following endovascular aneurysm repair (EVAR). Normally the aortic stent-graft used for EVAR excludes the aneurysm from the circulation by providing a conduit for blood to bypass the sac.
An endoleak is a...
Barrow caroticocavernous fistula classification divides caroticocavernous fistulas into direct (type A) or indirect (types B-D). This classification was proposed by Barrow et al. in 1985 1 and at the time of writing (mid-2016) remains the most widely used system for describing caroticocavernous ...
May-Thurner syndrome refers to a chronic compression of the left common iliac vein (CIV) against the lumbar vertebrae by the overlying right common iliac artery (CIA), with or without deep venous thrombosis 2.
Although both left and right CIVs lie deep to the right common iliac artery, the left...
The WFNS (World Federation of Neurosurgical Societies) grading system uses the Glasgow Coma Scale and presence of focal neurological deficits to grade the clinical severity of subarachnoid hemorrhage. This grading system was proposed in 1988, and this is one of the accepted systems (although not...
The Hunt and Hess scale describes the clinical severity of subarachnoid hemorrhage resulting from the rupture of an intracerebral aneurysm and is used as a predictor of survival.
asymptomatic or minimal headache and slight neck stiffness
moderate to severe heada...
The Fisher scale is the initial and best known system of classifying the amount of subarachnoid hemorrhage on CT scans, and is useful in predicting the occurrence and severity of cerebral vasospasm, highest in grade 3 2.
Numerous other scales have been proposed, incorporating various parameter...
Page kidney, or Page phenomenon, refers to systemic hypertension secondary to extrinsic compression of the kidney by a subcapsular collection, e.g. hematoma, seroma, or urinoma.
Patients present with hypertension, which may be recognized acutely after an inciting event or...
Hyperreninaemic hypertension may have many causes including:
renal artery stenosis
renal secreting tumor, e.g. renal cell carcinoma, reninoma
renal compression: large renal mass, subcapsular hemorrhage (Page kidney)
Renal artery stenosis (RAS) (plural: stenoses) 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 a...
The differential for thoracic aortic stenosis includes:
aortitis (especially Takayasu arteritis)
Williams syndrome: supravalvular aortic stenosis
congenital rubella syndrome: supravalvular aortic stenosis
There is a broad differential for thoracic aortic dilatation.
post-stenotic dilatation, e.g. bicuspid aortic valve
thoracic aortic aneurysm
atherosclerosis (usually descending thoracic aorta)
Fibromuscular dysplasia is classified into 5 categories according to the vessel wall layer affected:
intimal fibroplasia (1%)
medial dysplasia (70%, the commonest type)
perimedial (subadventitial) fibroplasia (15-20%)
medial hyperplasia (8-10%)
Fibromuscular dysplasia (FMD) is a heterogeneous group of vascular lesions characterized by an idiopathic, non-inflammatory, and non-atherosclerotic angiopathy of small and medium-sized arteries.
The prevalence is unknown 7. It is most common in young women with a female to male r...
The staging system for moyamoya disease first described by Suzuki and Takaku in their seminal 1969 article 1 is still in use today. Formally, the staging refers to findings on conventional angiography, although there are efforts to apply similar systems to MR angiography 2.
Suzuki stage appears...
Wyburn-Mason syndrome (also known as Bonnet-Dechaume-Blanc syndrome) is a rare, nonhereditary neurocutaneous disorder that typically presents with unilateral vascular malformations that primarily involve the brain, orbits and facial structures. It is currently classified as a craniofacial arteri...
Vein of Galen aneurysmal malformations (VGAMs), probably better termed as median prosencephalic arteriovenous fistulas, are uncommon intracranial anomalies that tend to present dramatically during early childhood with features of a left-to-right shunt and high-output cardiac failure.
Vasculitis describes generalized inflammation of vessels. Vasculitides carry a broad range of clinical presentations and as a whole can involve almost any organ system.
Some vasculitides are due to direct vessel injury from an infectious agent. However, a large proportion show eviden...
The are numerous vascular syndromes that can occur in the body. They include:
Syndromes principally involving the vascular system
celiac artery compression syndrome
hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
hypothenar hammer syndrome
Vascular anatomical variants are common:
SVC and IVC - caval variants
intracranial arteries - variants
Blood vessel derived tumors may arise from:
cells supporting or surrounding blood vessels
glomus tumor of finger
Most arise in the soft tissues or viscera. Primary tumors of the large vessels (eg. aorta, IVC) are ...
Tumor thrombus is defined as tumor extending into a vessel, typically a vein. It occurs in a wide variety of malignancies. It is vital to distinguish tumor thrombus from "bland" thrombus (free of neoplastic cells) in the setting of neoplasia, as this often impacts staging and treatment approach....
In a true aneurysm, the aneurysm is bound by all three layers of the vessel wall (intima, media and adventitia). The wall may be attenuated. The risk of rupture is proportional to the size of the aneurysm.
The thyroidea ima artery is an uncommon variant of the blood supply to the inferior aspect of the thyroid gland. It is reported in ~7.5% (range 1.5-12.2%) of individuals and can arise from:
brachiocephalic trunk (most common: 1.9-6.0%)
right common carotid artery
Thoracic outlet syndrome refers to a group of clinical syndromes caused by congenital or acquired compression of the brachial plexus or subclavian vessels as they pass through the superior thoracic aperture 11.
Clinical presentation will depend on the structure compresse...
The thoracic aorta is the most superior division of the aorta and is divided into three sections:
The thoracic aorta begins at the aortic valve, located obliquely just to the left of the midline at the level of the third intercostal space. It term...
Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life-ending event.
Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical...
Takayasu arteritis (TAK), also known as idiopathic medial aortopathy or pulseless disease, is a granulomatous large vessel vasculitis that predominantly affects the aorta and its major branches. It may also affect the pulmonary arteries. The exact cause is not well known but the pathology is tho...
von Hippel-Lindau disease
Subarachnoid hemorrhage (SAH) is a type of extra-axial intracranial hemorrhage and denotes the presence of blood within the subarachnoid space.
Patients tend to be older middle age, typically less than 60 years old 2. Subarachnoid hemorrhage accounts for 3% of stroke and 5% of str...
The string sign may refer to:
angiographic string sign
gastrointestinal string sign
string sign of parosteal osteosarcoma
myositis ossificans string sign
String of pearls sign can refer to:
string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops
string of pearls sign on cerebral MRI in deep border zone infarction
string of pearls sign on ultrasound in polycystic ovarian syndrome
string of pearls sign for ang...
Stewart-Treves syndrome refers to an angiosarcoma seen in the setting of lymphedema 1.
It was classically attributed to lymphedemas induced by radical mastectomy to treat breast cancer. Nowadays, we know that it can arise in chronically lymphedematous regions of any cause 2.
The incidence is ...
The Stanford classification, along with the DeBakey classification, is used to separate aortic dissections into those that need surgical repair, and those that usually require only medical management 7.
Both the Stanford and DeBakey systems can be used to describe all forms of an acute aortic s...
Spinal arteriovenous malformations can be classified in a number of ways:
extramedullary: 80% 1
Or into four types 2:
type I: single coiled vessel (spinal dural AV fistula)
type II: intramedullary glomus AVM
type III: juvenile
type IV: intradural perimedullary (AV fistula)...
The Spetzler-Martin arteriovenous malformation (AVM) grading system allocates points for various angiographic features of intracranial arteriovenous malformations to give a score that predicts the morbidity/mortality risk of surgery 5.
The grading system requires correlation between C...
Situs inversus, (rare plural: sitūs inversi) short form of the Latin “situs inversus viscerum”, is a term used to describe the inverted position of chest and abdominal organs.
The condition is called situs inversus totalis when there is a total transposition of abdominal and thorac...
Situs classification (plural: sitūs) or body situs can be a daunting topic, but it falls into three main groups:
situs solitus: the normal configuration of thoracic and abdominal organs
situs inversus: mirror image of the normal configuration
situs ambiguus (heterotaxy): an intermediate confi...
The sinotubular junction is the region of the ascending aorta between the aortic sinuses (of Valsalva) and where the normal tubular configuration of the aorta is attained. It marks the junction of the aortic root and ascending aorta.
Scimitar syndrome, also known as hypogenetic lung syndrome, is characterized by a hypoplastic lung that is drained by an anomalous pulmonary vein into the systemic venous system. It is a type of partial anomalous pulmonary venous return and is one of the several findings in congenital pulmonary ...
Superior vena caval (SVC) duplication is the most common form of a left-sided SVC, where the normal right-sided SVC remains. The right SVC, however, can be smaller in approximately two-thirds of such cases 3.
Results from failure of the embryonic left anterior cardinal vein to regres...
Systemic hypertension is defined medically as a blood pressure greater than 140/90 mmHg. Recently the American College of Cardiology (ACC) and American Heart Association (AHA) have changed guidelines to indicate that pressures above 130/80 mmHg will be considered hypertension, however the Europe...
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 ...
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.
Non-thrombotic pulmonary emboli sour...
Pulmonary arteriovenous malformations (PAVMs) 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 pulmona...
A pulmonary arterial stenosis refers to a narrowing of the pulmonary artery or pulmonary trunk can be classified into several types 1,2:
type I: involving main pulmonary artery (pulmonary trunk)
type II: involving bifurcation
type III: multiple peripheral stenoses
type IV: central and periph...
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...
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, centr...