The paired left and right transverse sinuses are major dural venous sinuses and arise from the confluence of the superior sagittal, occipital and straight sinuses at the torcular herophili (confluence of sinuses).
On each side, the transverse sinus then runs in the lateral border of the tentori...
Traumatic aortic injury (TAI) is most often caused by blunt trauma (referred to as BTAI) and is best described in terms of injury location, type and severity:
abdominal aortic injury
thoracic aortic injury
minimal aortic injury
See traumatic aortic injury in the exam.
Getting a film with traumatic aortic injury in the exam is one of the many exam set-pieces that can be prepared for.
This is one of the cases you should look and not speak for 10 seconds as there tends to be a lot of findings on the film of patients with a traumatic aortic injury.
A useful mnemonic to remember the tributaries of the inferior vena cava is:
I Like To Rise So High
I: common iliac veins
L: lumbar veins
T: right testicular (gonadal) vein
R: renal veins
S: suprarenal veins
H: hepatic veins
The trident appearance (or sign) can refer to a variety of entities:
trident sign (osmotic demyelination)
trident sign (persistent trigeminal artery)
History and etymology
The trident is a three-pronged lance employed for spearing fish, and in Classical myth...
The trident sign of a persistent primitive trigeminal artery refers to the appearance of the intracranial circulation on lateral projection. The internal carotid artery, the abnormal vessel and superior portion of the basilar artery resemble the Greek letter tau (thus tau sign). This configurati...
Triple-rule-out CT (TRO CT) angiography may be ordered in the setting of acute chest pain to examine the thoracic aorta and the coronary and pulmonary arteries. The protocol helps exclude life-threatening causes of acute chest pain, especially if atypical, or if alternative causes to acute coron...
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.
Tuberculous aortitis is a rare cause of aortitis in the context of disseminated tuberculosis. It usually is a result of direct seeding from a contiguous lymph node or via hematogenous or lymphatic spread of distant infection. Fatal outcomes of tuberculous aortitis are commonly reported despite a...
Tulip bulb sign refers to the characteristic appearance of annuloaortic ectasia as seen on CT angiography.
There is symmetric dilatation of the three sinuses of Valsalva, with extension into the ascending aorta and effacement of the sinotubular junction.
It is seen especially in Marfan syndro...
Tumor necrosis factor receptor-associated periodic syndrome (or sometimes abbreviated as TRAPS) is a condition characterized by recurrent (periodic) episodes of fever as well as spectrum of dermatologic findings, including migratory patches, edematous plaques, periorbital edema, and/or conjuncti...
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....
Tunica is a word used in anatomy to refer to a type of covering.
tunica adventitia (also known as tunica externa)
tunica albuginea (clitoris)
tunica albuginea (ovary)
tunica albuginea (penis)
tunica albuginea (testis)
A tunnel syndrome refers to pain, paresthesia and weakness due to neurovascular compression, friction or traction within a confined anatomical passageway. The tunnel may be bordered by bone, muscle or tendoligamentous structures or a combination of these.
Various specific syndromes exist and ar...
Type I endoleaks are a subgroup of endoleaks which occur at graft ends, often due to an inadequate seal.
They occur as a result of poor apposition between one of the attachment sites of a stent-graft and the native aortic or iliac artery wall. Blood can leak through this defect into...
A type II endoleak is a commonest form of endoleak are after an abdominal aortic repair.
They are the most common types of endoleaks and may occur in 10-44% of patients having repairs and can comprise around half of all endoleaks 1.
They may be simple or complex. Simp...
A type III endoleak is a type of endoleak which usually occurs through a defect in the graft. It may be divided into two components.
IIIa: junctional separation of the modular components
IIIb: fractures or holes involving the endograft
It is relatively uncommon and only occurs ...
Type IV endoleaks are a type of endoleak which usually occurs secondary to graft porosity and are typically seen in the immediate post operative angiogram following an endovascular aneurysm repair.
Type IV endoleaks are extremely rare and studies report a prevalence of 0.3%. This ...
The ulnar artery is a terminal branch of the brachial artery, arising at the proximal aspect of the forearm. Along with the radial artery, it is one of the main arteries of the forearm.
origin: terminal branch of the brachial artery
location: inferior aspect of the cubital fossa
The ulnar vein is one of the two major deep veins of the forearm, along with the radial vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the ulnar artery and anastomose freely with each other.
It forms in the hand from the d...
Ultrasound assessment of carotid arterial atherosclerotic disease has become the first choice for carotid artery stenosis screening, permitting the evaluation of both the macroscopic appearance of plaques as well as flow characteristics in the carotid artery.
This article focus on internal caro...
Peripheral intravenous cannulation under ultrasound guidance is the placement of a cannula into a peripherally-located vein under the direct vision of ultrasound. This process allows the cannulation of veins that are unable to be visualized or palpated without ultrasound. In trained individuals ...
An umbilical arterial aneurysm (UAA) is an extremely rare but potentially lethal vascular anomaly which is usually detected in utero.
It tends to favor the placental end of the umbilical artery in the cord.
Concurrently associated anomalies are thought to be...
Umbilical arterial catheters (UACs) are used in neonatal care for arterial sampling and need to be carefully assessed on all neonatal films.
The catheter should pass through the umbilicus, travel inferiorly through the umbilical artery, then in the anterior division of the internal i...
The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation and an active vessel giving supply to the bladder. In the adult, the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery.
The umbilical cord is a fetal organ that connects the placenta to the developing fetus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.
The umbilical cord inserts into the center of the placental bulk and into the fetus at the umbilicus. Vari...
The umbilical vein is the conduit for blood returning from the placenta to the fetus until it involutes soon after birth.
The umbilical vein arises from multiple tributaries within the placenta and enters the umbilical cord, along with the (usually) paired umbilical arteries. Once it enters the...
Umbilical vein varix (UVV) refers to a focal dilatation of the umbilical vein.
UVVs were initially thought to have a high association with other anomalies which include:
chromosomal anomalies: 5-12% with FIUVV 2,3
underlying congenital cardiovascul...
Umbilical venous catheters (UVCs) are commonly used in neonates for vascular access and should be carefully assessed for position on all neonatal films.
An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes through...
The umbilicus is the fibrous remnant of the fetal attachment of the umbilical cord after birth.
All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the st...
The term unfolded aorta refers to the widened and 'opened up' appearance of the aortic arch on a frontal chest radiograph. It is one of the more common causes for apparent mediastinal widening and is seen with increasing age.
It occurs due to the discrepancy in the growth of the ascending aorta...
Unilateral pulmonary artery atresia (UPAA), also known as unilateral absence of the pulmonary artery (UAPA) or proximal interruption of the pulmonary artery, is a variant of pulmonary artery atresia.
The term interruption is preferred by some to absence or atresia because the anom...
Unilateral pulmonary vein atresia is a type of pulmonary vein atresia.
The condition usually present in infancy or childhood with recurrent episodes of pneumonia and/or hemoptysis. Presentation in adulthood does occur but is uncommon.
It results from failure o...
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...
An upper gastrointestinal bleed usually refers to bleeding proximal to the ligament of Treitz.
Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
Uterine arteriovenous malformations (UAVM) result from the formation of multiple arteriovenous fistulous communications within the uterus without an intervening capillary network.
The presentation can vary. UAVMs can cause life-threatening massive bleeding in young women....
The uterine artery is seen bilaterally and is a branch of the anterior division of the internal iliac artery.
It runs medially in the pelvis, within the base of the broad ligament, to the outer surface of the uterus. From lateral to medial it has a descending, transverse ...
Uterine artery embolization (UAE) is an interventional radiological technique to occlude the arterial supply to the uterus and is performed for various reasons.
Uterine artery embolization has been practised for more than 20 years for controlling hemorrhage following delivery/abortion,...
Uterine artery embolization (UAE) is used as an alternative to hysterectomy in selected patients and MRI assessment is key in allowing not only pre-procedure assessment but also assessing post-procedural outcome.
For a general discussion of the underlying condition refer to the article on ute...
Uterine artery flow notching refers to a phenomenon observed in uterine arterial Doppler ultrasound assessment.
The presence of notching after 22 weeks is associated with several other conditions including adverse pregnancy outcomes. These include
pregnancy induced hyp...
Uterine artery pseudoaneurysm (UAP) is a rare cause of secondary postpartum hemorrhage.
UAP usually presents as delayed (secondary) postpartum hemorrhage, that is per vaginal bleeding which occurs more than 24 hours and up to 6 weeks postpartum. However, some reported ca...
The uterine venous plexus is a network of veins surrounding the uterus and has extensive anastomoses with the vaginal venous plexus inferiorly and ovarian venous plexuses laterally.
The uterine venous plexus lies along the lateral aspects and superior angles of the uterus within ...
The vaginal artery is a branch of the anterior division of the internal iliac artery, and should not to be mistaken with the vaginal branch of the uterine artery. It is often considered to be a homolog of the inferior vesical artery, which is present only in males.
origin: anterior div...
The Valsalva maneuver is the forced expiration of air against a closed airway, resulting in increased intra-abdominal, intrathoracic, and pharyngeal pressure. It can be performed against a closed glottis or by one closing the mouth and pinching the nose while forcibly exhaling.
It is commonly u...
The valveless veins are veins that lack venous valves. Most veins contain valves (known as the valvula venosa in the TA) to prevent backflow, i.e. ensuring that blood flow is always towards the heart 1.
Recent evidence shows that veins that were previously thought to be valveless, are now known...
Variant anatomy of the aortic arch occurs when there is failure of normal aortic development. It results in a number of heterogenous anomalies of the aorta and its branch vessels.
Normally, the aorta ascends in the superior mediastinum to the level of the sternal notch before arc...
Variation in hepatic arterial anatomy is seen in 40-45% of people. Classic branching of the common hepatic artery from the celiac artery, and the proper hepatic artery into right and left hepatic arteries to supply the entire liver, is seen in 55-60% of the population.
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...
Varicocele embolization is a minimally invasive method of treating varicoceles by embolizing the testicular vein (internal spermatic veins).
failed surgical ligation
Relative contraindications include:
Varicocele grading on color Doppler can be done variably. The most elaborate and widely-accepted grading was given by Sarteschi, as below.
For a general discussion of this condition refer to the article: varicocele.
baseline greyscale study in supine position and measure the diame...
Varicose veins are dilated tortuous superficially located venous channels that accompany the superficial veins of the upper or lower limbs.
Varicose veins are more common in women than men and are more common in the lower limb than in the upper limb 5. Risk factors include:
Vascular anatomical variants are common:
SVC and IVC - caval variants
intracranial arteries - variants
Vascular compression disorders are numerous and can be divided into those cases where a vascular structure is the "compress-er" or the "compress-ee" . Some conditions fall into both categories, where one vessel compresses another.
Compression of a vascular structure
Vascular Ehlers-Danlos syndrome (EDS) or type IV Ehlers-Danlos syndrome (EDS 4) is the most malignant form of Ehlers-Danlos syndrome. This form is often accompanied by neurovascular complications secondary to vessel dissections and/or aneurysms.
Vascular EDS represents about 4% of...
Vascular malformations and tumors are a heterogeneous group of lesions that may affect the arterial, capillary, venous or lymphatic system or any combination thereof. They encompass a bewildering range of lesions, syndromes, and masses ranging from the relatively common (e.g. infantile hemangio...
Vascular pathologies are common and include:
inherited disorders of the vessel wall
tumors of blood vessels
congenital vascular anomali...
Vascular rings and slings refer to the congenital vascular encirclement of the esophagus and/or trachea by anomalous/aberrant vessels.
Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.
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
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 evidenc...
Vasculopathies caused by varicella zoster virus (VZV) represent a group of illnesses involving both small and large CNS arteries caused by a inflammatory process involving the media and the vascular endothelium. Usually it occurs in immunocompromised individuals due the viral reactivation and sp...
The vein of Galen, also known as the great cerebral vein or great vein of Galen, is a short valveless trunk formed by the union of the two internal cerebral veins and basal veins of Rosenthal.
It lies in the quadrigeminal cistern and curves backward and upward around the posterio...
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.
The vein of Marshall, oblique vein of Marshall or the oblique vein of the left atrium is a small vein that descends on and drains the posterior wall of the left atrium. It drains directly into the coronary sinus at the same end as the great cardiac vein, marking the origin of the sinus.
Velocity encoding or Venc is referred to as an operator-controlled parameter for the determination of the maximum velocity within a velocity encoded phase contrast imaging study.
Velocity-encoding (Venc) gradients are used to generate a phase shift in magnetic resonance phase contrast im...
The vena caval foramen is one of the three major apertures in the diaphragm. It is the highest of the three and situated at the level of T8-9. It is quadrilateral and placed at the junction of the right and middle leaflets of the central tendon.
It transmits several structures between the thora...
The venae cordis minimae (singular: vena cordis minima), meaning "smallest cardiac veins", also known as thebesian veins (as these are eponymous, they are sometimes capitalized as Thebesian veins) are a small group of valveless myocardial coronary veins within the walls of each of the four cardi...
Veno-occlusive mesenteric ischemia is most often the result of superior mesenteric vein (SMV) thrombosis and is a less common cause of acute mesenteric ischemia. Often despite thrombosis of the SMV, small bowel necrosis does not occur, presumably due to persistent arterial supply and some venous...
The anastomotic venous circle of the base of the brain 1, also referred to as the venous circle of Trolard 2,3,5, is an inconsistently found venous homologue of the better-known arterial circle of Willis.
It should not be confused with other venous structures also described by Trolard such as t...
Venous drainage of the foot can be divided into two main components. Plantar veins, draining the sole (plantar surface) of the foot, and the dorsal veins which drain the dorsal surface of the foot. The veins of the foot are susceptible to several pathologies, including corona phelbectatica, vari...
Venous drainage of the hand is predominantly via the dorsal venous network in the superficial fascia, which extends proximally across the dorsal aspect of the metacarpus to drain laterally into the cephalic vein, and medially into the basilic vein 1. An accessory cephalic vein commonly drains pa...
The anatomy of the venous drainage of the lower limbs is extremely variable. However, there is order in the variability. The veins of the lower extremities are arranged in three systems: the superficial, the deep, and the perforating venous systems. These are located in two main compartments: th...
The venous drainage of the thoracic wall drains deoxygenated venous blood from the peripheries of the thoracic cage back into systemic circulation.
Anterior thoracic wall
Anterior intercostal veins
The anterior intercostal veins originate from the intercostal space just inferio...
The venous thoracic outlet syndrome is the second commonest form of thoracic outlet syndrome (with neurogenic thoracic outlet syndrome being the commonest and the arterial thoracic outlet syndrome being the least common).
It may develop suddenly, often after unusual and t...
Venous thromboembolism covers a wide spectrum of diseases. Individual conditions and complicating condition include:
deep vein thrombosis (DVT)
pulmonary embolism (PE)
dural venous sinus thrombosis
The vertebral arteries (VA) are paired arteries, each arising from the respective subclavian artery and ascending in the neck to supply the posterior fossa and occipital lobes, as well as provide segmental vertebral and spinal column blood supply.
origin: branches of the 1st part of th...
Vertebral artery dissection, like arterial dissection elsewhere, is a result of blood entering the media through a tear in the intima. It is potentially lethal and can be difficult to diagnose clinically and radiologically.
Vertebral artery dissections have an incidence of 1-5 per...
Vertebral artery ectasia refers to an abnormal dilatation of the vertebral artery. It is also known as a dolichoarterial loop (of Danziger).
Symptoms occur due to radicular compression or pathologic fracture (rare) from extensive bone erosion. Generally, patients present ...
Vertebral artery loops occur when a portion of the vertebral artery contains an unusual coil. It can be a rare anatomical variant or can be acquired.
Vertebral artery loops tend to be mostly diagnosed in the 5th and 6th decades. Its prevalence is uncertain but is thought to be pre...
Vertebral artery thrombosis results in complete or partial occlusion of the vertebral artery and alteration of blood flow to the posterior cerebral circulation. Ischemia or infarction to structures supplied by these arteries may result in a range of symptoms.
The vertebral venous plexus is a highly anastomotic network of valveless veins running along the entire length of the vertebral column from the foramen magnum to the sacral hiatus.
The vertebral venous plexus is comprised of three interconnected divisions:
internal vertebral ven...
Vertebrobasilar insufficiency is a clinical syndrome caused by transient ischemia of the vertebrobasilar circulation, formed by the vertebral and basilar arteries, which forms the posterior circulation of the brain 1.
Vertebrobasilar insufficiency is largely caused by atheroscler...
A vestibule is an anatomical term and refers to a small cavity at the proximal end of a tube. It may refer to:
History and etymology
Vestibule derives ultimate...
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.
Virchow triad refers to the factors which can promote thrombosis, these are useful to consider when thinking about the possible causes in a particular situation. They are:
factor V Leiden
protein S deficiency
protein C deficiency
antithrombin III de...
Visceral artery aneurysms are abnormal focal dilatations of arteries supplying abdominal organs. Visceral artery aneurysms include both true aneurysms and pseudoaneurysms.
Owing to different clinical manifestations and a unique, specific, pathology, renal artery aneurysms are discussed separate...
Wells criteria for deep venous thrombosis is a risk stratification score and clinical decision rule to estimate the pretest probability for acute deep venous thrombosis (DVT). It is intended to be combined with noninvasive diagnostic tests (e.g. ultrasound or D-dimer) for suspected cases. D-dime...
Westermark sign is a sign of pulmonary embolus seen on chest radiographs. It is one of several described signs of pulmonary embolus on chest radiographs.
The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3.
In one stu...
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 white coat effect (WCE), not to be confused with white coat hypertension, is a measure of change that is commonly defined as the difference between in-clinic and out-of-clinic blood pressure readings 1,2.
Alternatively, the white coat effect can be defined as the increase in the arterial b...
White coat hypertension (abbreviated alternatively as WCH or WCHT), not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readi...
Williams syndrome (WS) is characterized by some or all of the following features:
craniofacial dysmorphism (e.g. elfin facies)
short stature (50% of cases)
mild to moderate intellectual disability
supravalvular aortic stenosis 2
pulmonary artery stenosis 3