Articles

Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

1,007 results found
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Normal mesenteric lymph nodes

Mesenteric lymph nodes had, during the era of single thick slice CT been only really appreciated when enlarged. With the advent of multidetector volume acquisition CT (and especially coronal reformats) they are commonly seen in normal individual and thus have raised the obvious question of what ...
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Normal oesophageal contours on barium swallow

There are a number of normal oesophageal contours or impressions that are encountered when performing a barium swallow. It is important to be able to differentiate normal contours and their variants, as well as contours that may indicate disease. Below is a list of anatomical structures that may...
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Normal postmortem changes in the gastrointestinal tract

Normal postmortem changes in the gastrointestinal tract​ refers to the normal changes that can be expected to be seen in the gastrointestinal tract on post-mortem imaging. Radiographic features CT The following changes may be present in the abdomen and gastrointestinal tract 1: intraluminal ...
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Northern exposure sign

The northern exposure sign has been described as a high specificity sign in sigmoid volvulus. On a supine abdominal radiograph, the apex of the sigmoid volvulus is seen above (cranial to) the transverse colon.
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Obstructive jaundice (summary)

This is a basic article for medical students and other non-radiologists Obstructive jaundice represents a set of conditions that cause jaundice by obstructing the flow of bile into the duodenum anywhere along the intrahepatic or extrahepatic biliary tree. Reference article This is a summary a...
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Obturator hernia

Obturator hernias are characterised by bowel herniating between the obturator and the pectineus muscles. They are a rare type of abdominal hernia and can be very difficult to diagnose clinically. Epidemiology Typically obturator hernias occur in elderly women 3,4 or patients with chronically r...
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Octreotide scintigraphy

Octreotide scintigraphy uses 111In-labelled octreotide which is a somatostatin analog; it is also known as an OctreoscanTM, a brand name for 111In-labelled pentetreotide; pentetreotide is a DTPA-conjugated form of octreotide, originally manufactured by Mallinckrodt Nuclear Medicine LLC, which no...
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Oesophageal atresia

An oesophageal atresia refers to an absence in the contiguity of the oesophagus due to an inappropriate division of the primitive foregut into the trachea and oesophagus. This is the most common congenital anomaly of the oesophagus.  Epidemiology It is thought to occur in ~1:3000-4500 live bir...
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Oesophageal atresia (classification)

Oesophageal atresia is closely related to tracheo-oesophageal fistula and can be divided into1: type A: isolated oesophageal atresia (8%) type B: proximal fistula with distal atresia (1%) type C: proximal atresia with distal fistula (85%) type D: double fistula with intervening atresia (1%) ...
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Oesophageal bronchus

Oesophageal bronchus refers to the rare occurrence where a bronchus arises directly from the oesophagus. Epidemiology It is more common in females with a M:F of 1:2 2.  Gross anatomy Oesophageal bronchi may be the main bronchus, which gives rise to oesophageal lung, or may be a lobar bronchu...
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Oesophageal cancer (staging)

Oesophageal cancer staging can depend slightly on whether the tumour is squamous cell or adenocarcinoma subtype. Due to the lack of a serosal layer, oesophageal cancer often tends to have mediastinal spread at the time of diagnosis. Staging TNM staging T staging Tx: primary tumour cannot be...
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Oesophageal cancer (summary)

This is a basic article for medical students and other non-radiologists Oesophageal cancer is a relatively uncommon tumour that occurs within the oesophagus of affected individuals. Patients present with symptoms of increasing dysphagia that progress from solid foods to liquids. Reference arti...
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Oesophageal carcinoma

Oesophageal carcinoma is relatively uncommon. It tends to present with increasing dysphagia, initially to solids and progressing to liquids as the tumour increases in size, obstructing the lumen of the oesophagus. Epidemiology Oesophageal cancer is responsible for <1% of all cancers and 4-10% ...
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Oesophageal diverticula

Oesophageal diverticula are sac or pouch projections arising from the oesophagus. Epidemiology They can occur in all ages but more frequent in adults and elderly people. Pathology Oesophageal diverticula are either: true diverticula: include all oesophageal layers false diverticula: contai...
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Oesophageal duplication

Duplication of the oesophagus has a range of macroscopic appearances, ranging from complete (which is very rare) to partial cystic duplication (oesophageal duplication cyst). It is the second most common gastrointestinal tract duplication after that of the ileum. Epidemiology A complete duplic...
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Oesophageal duplication cyst

Oesophageal duplication cysts are a type of congenital foregut duplication cyst. Epidemiology Less common compared to other foregut duplication cysts. There may be an increased male predilection 5. Clinical presentation Patients are generally asymptomatic but may complain of dysphagia due to...
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Oesophageal dysmotility

Oesophageal dysmotility refers to the pathological disruption of the normal sequential and coordinated muscle motion of the oesophagus to transport food from the oropharynx to the stomach. It is an umbrella term used to refer to the common pathophysiological endpoint of dysmotility that can be c...
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Oesophageal fibrovascular polyp

Oesophageal fibrovascular polyps are benign intraluminal submucosal pedunculated tumours that can grow significantly and cause dysphagia symptoms. They usually occur in the upper third of the oesophagus, at the level of the upper oesophageal sphincter.  Terminology They were previously denomin...
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Oesophageal food impaction

Oesophageal food impaction (or steakhouse syndrome) refers to a food bolus acutely obstructing the oesophagus. Clinical presentation The main symptom is usually acute dysphagia. Radiographic features Plain radiograph Depending on the composition of the ingested content, the bolus may be vis...
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Oesophageal hiatus

The oesophageal hiatus is the opening in the diaphragm through which the oesophagus passes from the thoracic to abdominal cavity. It is one of three apertures in the diaphragm and is located in the right crus. It is situated in the muscular part of the diaphragm at the level of T10 and is ellip...
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Oesophageal leiomyoma

Oesophageal leiomyoma is a benign smooth muscle neoplasm of the oesophagus. It is the most common benign tumour of the oesophagus. Epidemiology It is most frequently presents in young and middle age groups (20-50 years). The overall incidence is around 8-43 per 10,000 autopsy series 4. Clinic...
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Oesophageal leiomyomatosis

Oesophageal leiomyomatosis is rare benign condition. Epidemiology It usually presents at childhood. There is a recognised increased female predilection. Pathology It is considered a hamartomatous condition and is associated with abnormal diffuse proliferation of smooth muscle fibres in dista...
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Oesophageal leiomyosarcoma

Oesophageal leiomyosarcoma is a rare malignant tumour of the oesophagus of smooth muscle origin.  Epidemiology The first case of oesophageal leiomyosarcoma was described in 1905.  Since then, there have been over 164 cases described in the literature. Radiographic features Fluoroscopy - Bari...
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Oesophageal lipoma

Oesophageal lipomas (or lipomata) are rare fat-containing oesophageal lesions. Epidemiology They may account for approximately 0.4% of the benign tumours of the alimentary tract 1. There may be greater male predilection. The average age of presentation is around 50 years.  Clinical presentati...
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Oesophageal mass (mnemonic)

A mnemonic to remember the causes of an oesophageal mass is: CALL the MVP Mnemonic C: carcinoma A: adenoma L: lymphoma L: leiomyoma M: metastasis V: varices P: papilloma/polyp
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Oesophageal myotomy

Oesophageal myotomy (or Heller myotomy) is a procedure that can be performed to treat a lower oesophageal sphincter that fails to relax (e.g. achalasia). The procedure involves a longitudinal incision of the distal oesophageal musculature to break the sphincter tone. A fundoplication wrap can b...
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Oesophageal perforation

Oesophageal perforation is a rare but serious medical emergency with a very high mortality rate, especially if the diagnosis is delayed. Epidemiology Most patients are in their 60s with a slight male predominance 5.  Clinical presentation If a perforation is not detected during the procedure...
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Oesophageal pseudodiverticulosis

Oesophageal intramural pseudodiverticulosis is an uncommon condition in which there are numerous small outpouchings within the oesophageal wall. Epidemiology It is a rare condition, found in <1% of oesophagrams. It may occur at any age, but is more common between ages  50 and 70. There is a sl...
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Oesophageal squamous papilloma

Oesophageal squamous papilloma is an uncommon finding on oesophagography (barium swallow). It is a benign lesion, but it is difficult to differentiate it from osophageal carcinoma on oesophagography and the diagnosis is usually made with endoscopic biopsy. Clinical presentation Often asymptoma...
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Oesophageal stent

Oesophageal stents are a treatment option in patients with oesophageal strictures. It is most commonly used for symptomatic relief in those with dysphagia secondary to malignancy. The stent is typically covered in nature and inserted endoscopically or fluoroscopically. The distal oesophagus is t...
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Oesophageal stricture

Oesophageal strictures refer to any persistent intrinsic narrowing of the oesophagus.  Pathology Aetiology The most common causes are fibrosis induced by inflammatory and neoplastic processes. Because radiographic findings are not reliable in differentiating benign from malignant strictures, ...
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Oesophageal web

Oesophageal webs refer to an oesophageal constriction caused by a thin mucosal membrane projecting into the lumen. Epidemiology Oesophageal webs tend to affect middle-aged females. Clinical presentation Patients are usually asymptomatic and the finding may be incidental and unimportant. Howe...
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Oesophagectomy

Oesophagectomy (or esophagectomy) is a surgical procedure that involves excision of the majority of the oesophagus and part of the proximal stomach, usually as a treatment for oesophageal carcinoma or carcinoma of the gastric cardia, although benign conditions (e.g. stricture) can be treated wit...
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Oesophagus

The oesophagus is a muscular tube that conveys food and fluids from the pharynx to the stomach. Gross anatomy The oesophagus is 23-37 cm long with a diameter of 1-2 cm and is divided into three parts: cervical: continuous with the hypopharynx, commences at the lower border of cricoid cartilag...
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Omega sign (disambiguation)

The omega sign can refer to a number of different anatomical structures or signs: omega sign (epiglottitis) omega sign (hand bump on the precentral gyrus)
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Omental cake

Omental cake refers to infiltration of the omental fat by material of soft-tissue density. The appearances refer to the contiguous omental mass simulating the top of a cake. Masses on the peritoneal surfaces and malignant ascites may also be present.  Pathology The most common cause is metasta...
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Omental infarction

Omental infarction is a rare cause of acute abdomen resulting from vascular compromise of the greater omentum. This condition has a non-specific clinical presentation and is usually managed conservatively. The term along with epiploic appendagitis is grouped under the broader umbrella term intra...
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Omental torsion

Omental torsion is defined as a twist of the omentum along its long axis with consequent impeding of its vascularity that may mimic acute abdomen 1. Epidemiology Omental torsion is a rare cause of acute abdominal pain that occurs in the third to fifth decade of life with slight male predomina...
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Omphalomesenteric fistula

Omphalomesenteric fistula occurs as aresult of failure of obliteration of the omphalomeseneric duct. It is one of the congenital fistulas of gastrointestinal tract . Treatment of choice is often a partial trans umbilical resection with umbilical restitution. See also gut fistulation
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Oral cholecystography

Oral cholecystography was a procedure used to image the gallbladder, now largely superseded by ultrasound and MRCP.  It was first described by Graham et. al in 1925, using sodium tetraiodophenolphthalein.  Although rarely performed now, more modern techniques used other cholegraphic agents such...
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Order of structures in the porta hepatis (mnemonic)

A useful mnemonic to help remember the order of structures in the porta hepatis from anterior to posterior is: DAVE D: ducts (right and left hepatic duct branches) A: arteries (right and left hepatic artery branches) V: vein (portal vein) E: epiploic foramen (of Winslow)  
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Pancreas

The pancreas is a retroperitoneal organ that has both endocrine and exocrine functions: it is involved in the production of hormones (insulin, glucagon and somatostatin), and also involved in digestion by its production and secretion of pancreatic juice. Gross anatomy The pancreas can be divid...
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Pancreas transplant

A pancreas transplant is a procedure performed in some medical centers in which a donor pancreas is transplanted to a recipient.  The donor pancreas is typically cadaveric, but may rarely be a segment from a living donor 1.  The transplant is meant to establish normoglycemia in patients with dia...
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Pancreatic atrophy

Pancreatic atrophy is non-specific and is common in elderly patients, although in younger patients it can be a hallmark of pathology. Most commonly it is associated with aging, obesity and end-stage chronic pancreatitis.  It occurs principally with fatty replacement of the pancreas (pancreatic ...
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Pancreatic calcifications

Pancreatic calcifications can arise form many aetiologies. Punctate intraductal calcifications acute alcoholic pancreatitis (20-40%)  intraductal, numerous, small, irregular preponderant cause of diffuse pancreatic intraductal calcification chronic pancreatitis idiopathic: no underlying ca...
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Pancreatic ductal adenocarcinoma (staging)

Staging of pancreatic ductal adenocarcinoma is traditionally done according to American Joint Committee on Cancer (AJCC) / Union for International Cancer Control (IUCC) TNM system.  In 2017 new edition (8th edition) AJCC published with some major changes; now exocrine and endocrine tumours of th...
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Pancreatic ducts

The pancreatic ductal embryology is moderately complicated, leading to a number of anatomical variants of the pancreatic ducts, many of which are clinically significant. The normal arrangement is for the entire pancreas to be drained via a single duct, to the ampulla of Vater through the sphinc...
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Pancreatic intraductal tubulopapillary neoplasm

Pancreatic intraductal tubulopapillary neoplasms (ITPNs) are rare variants of intraductal papillary neoplasms. Unlike an IPMN, an ITPN does not produce mucin. Epidemiology Incidence/prevalence is unclear. Small series show an even male:female distribution and an average age of presentation of ...
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Pancreatic intraepithelial neoplasia

Pancreatic intraepithelial neoplasia (PanIN) is a precursor lesion to pancreatic ductal adenocarcinoma, but the frequency at which this transition occurs is unknown.  Epidemiology Increasing incidence with age 1. Risk factors: obesity pancreatic lipomatosis 3 Pathology Mostly flat lesions ...
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Pancreatic lipoma

Pancreatic lipomas are uncommon mesenchymal tumors of the pancreas. Clinical presentation Rarely symptomatic, they are most often detected incidentally on cross-sectional imaging for another purpose. If they do cause symptoms, it will typically be those related to regional mass effect from the...
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Pancreatic lipomatosis

Pancreatic lipomatosis refers to the fatty replacement of pancreatic parenchyma. This finding is most often associated with obesity and ageing.  It tends to be commonest pathological condition involving the pancreas. The condition may occasionally simulate a mass-like lesion particularly when f...
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Pancreatic lymphangioma

Pancreatic lymphangiomas are benign lesions that are often found incidentally during cross-sectional imaging for another reason. Clinical presentation More common in adults (in contrast to lymphangiomas in the head and neck, which are more common in children). Account for approximately 1% of a...
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Pancreatic lymphoma

Pancreatic lymphoma is most commonly a B-cell sub-type of non-Hodgkin lymphoma. Epidemiology Typically seen in middle-aged patients: mean of 55 years; range, 35-75 years and in immunocompromised patients. Clinical presentation Presentation is often non-specific. reported symptoms include 1: ...
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Pancreatic mesenchymal neoplasms

Pancreatic mesenchymal neoplasms (or pancreatic nonepithelial neoplasms) are a group of rare pancreatic neoplasms that arise from the structural elements of the pancreas (nerves, fat, lymph), rather than from the exocrine or endocrine cells of the pancreas. Neoplasms from exocrine and endocrine ...
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Pancreatic neoplasms

There are numerous primary pancreatic neoplasms, in part due to the mixed endocrine and exocrine components. Classification Classification based on function exocrine: ~99% of all primary pancreatic neoplasms pancreatic ductal adenocarcinoma ~90-95% cystic neoplasm intraductal papillary muc...
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Pancreatic neurofibroma

Pancreatic neurofibromas are rare nonepithelial neoplasms of the pancreas. They are similar to neurofibromas found elsewhere in the body, and are associated with neurofibromatosis type I.  Clinical presentation If they do cause symptoms, it will typically be those related to regional mass effe...
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Pancreaticopleural fistula

Pancreaticopleural fistulas are a rare complication of acute or chronic pancreatitis whereby enzymatic pancreatic fluid, either from a pancreatic pseudocyst or directly from a disrupted duct, dissects into the pleural cavity. Pancreaticopleural fistulas may also develop in the setting of trauma ...
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Pancreatic PEComa

Pancreatic perivascular epithelioid cell tumours (or "Pancreatic PEComas") are a subtype of the larger family of PEComas. Pancreatic PEComas are very rare with <20 cases described. Clinical presentation More common in adults (in contrast to lymphangiomas in the head and neck, which are more co...
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Pancreatic pseudocyst

Pancreatic pseudocysts are common sequelae of acute pancreatitis or chronic pancreatitis, and the most common cystic lesion of the pancreas. They are important both in terms of management and differentiation from other cystic processes or masses in this region. Terminology The following are th...
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Pancreatic trauma injury grading

A number of pancreatic injury grading systems have been proposed. Classifications American Association for the Surgery of Trauma (AAST) grade 1: haematoma with minor contusion/laceration but without duct injury grade 2: major contusion/laceration but without duct injury grade 3: distal lace...
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Pancreatic ultrasound

Pancreatic ultrasound can be used to assess for pancreatic malignancy, pancreatitis and its complications, as well as for other pancreatic pathology. Preparation Fast the patient to reduce interference from overlying bowel gas, which may otherwise make visualisation difficult. Scanning techni...
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Pancreatitis

Pancreatitis refers to inflammation involving the pancreas.  It has various forms which can be classified in many many ways according to time of onset, aetiological agent or associated pathology. acute pancreatitis interstitial oedematous pancreatitis necrotising pancreatitis haemorrhagic p...
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Pancreatoblastoma

Pancreatoblastomas are rare paediatric tumours of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein. Epidemiology There is slight male predilection. Usually occurs in the first decade of life with a mean ag...
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Pantaloon hernia

A pantaloon hernia (dual hernia, Romberg's hernia or saddle bag hernia) is defined as ipsilateral, concurrent direct and indirect inguinal hernias. Hernial sacs are present on both sides of the inferior epigastric vessels, and separated by the posterior wall of the inguinal canal brought down by...
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Para-aortic lymph nodes

Para-aortic lymph nodes are located anterior to the left lumbar trunk 1 and above and below the left renal vein prior to the flow of lymph into the cisterna chyli 2-4.
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Paraduodenal hernia

Paraduodenal hernias, although uncommon, have classically been the most common type of internal hernia. However, incidence of postoperative internal hernias have been increasing recently. The two most common types, the left and right paraduodenal hernia involve small bowel herniating through a c...
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Paraduodenal pancreatitis

Paraduodenal pancreatitis is an uncommon type of focal chronic pancreatitis affecting the groove between the head of the pancreas, the duodenum and the common bile duct. Terminology The following entities with which it shares clinicopathological features are unified by this term and should no ...
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Paralytic ileus (mnemonic)

A mnemonic for the common causes of paralytic ileus is: 5 Ps Mnemonic The classic "5 Ps" are: P: postoperative P: peritonitis P: potassium: low (also disturbances of other electrolytes) P: pelvic and spinal fractures P: parturition However, there are a few further Ps that can be include...
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Paraneoplastic syndromes

Paraneoplastic syndromes occur secondary to the indirect effects of a malignancy and occur remotely to the primary malignancy. Symptoms are mediated by cytokines, hormones or immune cross-reactivity. These syndromes can cause a diverse range of symptoms and can affect multiple systems. Epidemio...
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Para-oesophageal hernia

Para-oesophageal hernias (POH), or rolling hernias, are an uncommon type of hiatal hernia representing ~10% of all hiatal hernias. The majority of the hiatal hernias being of the sliding type. Clinical presentation Can vary and can include: asymptomatic gastro-oesophageal reflux disease (mai...
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Parastomal hernia

Parastomal hernia is defined as the protrusion of abdominal contents through an abdominal wall defect in the vicinity of the stoma. Classification The hernia may contain a loop of bowel forming the stoma itself, omentum, and/or intestinal loops other than that forming the stoma. Based on the c...
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Parasympathetic pelvic splanchnic nerves

The pelvic splanchnic nerves also known as nervi erigentes are preganglionic (presynaptic) parasympathetic nerve fibres that arise from S2, S3 and S4 nerve roots of the sacral plexus. These nerves form the parasympathetic portion of the autonomic nervous system in the pelvis.   Gross anatomy O...
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Paraumbilical hernia

Paraumbilical hernias are a type of midline ventral abdominal hernia. Pathology Paraumbilica hernias occur near the umbilicus and abdominal contents protrude through a defect in the linea alba and can be quite large. They are usually related to rectus abdominis muscle diastasis.  Differential...
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Paravesical space

The paravesical spaces are paired avascular spaces of the pelvis. The paravesical spaces generally contain fat, but can become filled with ascites, blood, or other substances during pathological processes. Gross anatomy Boundaries superior: lateral umbilical folds inferior: pubocervical fasc...
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Passavant cushion

The Passavant cushion is a small prominence in the posterior pharynx, formed from a focal bulge of the superior pharyngeal constrictor muscles during swallowing. The "cushion" opposes the soft palate during the act of swallowing and is part of the seal between soft palate and pharynx that preve...
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Pathology in general surgery (summary)

Pathology in general surgery is predominantly intra-abdominal and the core set of conditions listed below is a starting point for final-year medical students: bowel perforation acute pancreatitis appendicitis acute cholecystitis diverticulitis intestinal ischaemia colorectal carcinoma ao...
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Pelvic lipomatosis

Pelvic lipomatosis or pelvic fibrolipomatosis represents excessive deposition of fat in pelvis due to overgrowth of adipose cells leading to compression of pelvic organs. Epidemiology The condition usually presents in patients 20-50 years of age. The condition is predominantly (2/3 of cases) s...
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Peptic ulcer disease

Peptic ulcer disease (PUD) encompasses a number of entities, united by the presence of mucosal ulceration secondary to the effects of gastric acid. Since the recognition of Helicobacter pylori as a common causative agent, and the development of powerful anti-acid medications, peptic ulcer diseas...
Article

Peptic ulcer disease (summary)

This is a basic article for medical students and other non-radiologists Peptic ulcer disease encompasses a number of entities that are the result of gastric mucosal ulceration secondary to the effects of gastric acid. Since the recognition of Helicobacter pylori as a common causative agent and ...
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Percutaneous endoscopic gastrostomy

Percutaneous endoscopic gastrostomy (PEG) is a procedure where a is a flexible feeding tube (commonly known as a PEG tube) is inserted through the abdominal wall and into the stomach. This may be placed under endoscopic or radiological guidance, in the latter, the procedure may be known as a per...
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Perforated appendix

A perforated appendix is one of the complications of acute appendicitis. If appendicitis is left untreated, ischaemic necrosis of a portion of appendiceal wall may occur, leading to perforation. An appendicolith is thought to be associated with a higher probability of perforation 1. Epidemiolog...
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Periampullary tumours

Periampullary tumours are those that arise within 2 cm of the ampulla of Vater in the duodenum. Tumours that fall under this group include four main types of tumours 1,4 that will be approached in their specific articles: pancreatic head/uncinate process tumours: includes pancreatic ductal ade...
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Perianal abscess

Perianal abscess refers to a formed infective-inflammatory collection within the perianal region. It forms part of the broader group of anorectal abscesses. They are often associated with perianal fistulae and are components of grades 2 and 4 fistulae of the St James’ University Hospital classif...
Article

Perianal fistula

Perianal fistula (or fistula-in-ano) is the presence of a fistulous tract across/between/adjacent to the anal sphincters and is usually an inflammatory condition 4. Epidemiology Incidence is estimated at ~1:10 000 1, with a recognised male predilection of 2-4:1. Associations spontaneous div...
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Pericaecal hernia

Pericaecal hernia is a rare type of internal hernia. Epidemiology It accounts for only 6-13% of internal abdominal hernias. Clinical presentation Clinical symptoms are often characterised by episodes of intense lower abdominal pain, like a colicky right lower quadrant pain very similar to th...
Article

Perigastric appendagitis

Perigastric appendgitis is a rare inflammatory/ischemic process involving the perigastric ligaments (gastrohepatic, gastrospleic and falciform ligaments). Epiploic appendagitis, greater omental infarction, and perigastric appendagitis have similar mechanisms, clinical presentations, and radiolo...
Article

Perineal hernia

Perineal hernias are rare pelvic hernias, occurring through a defect in the pelvic floor musculature. Epidemiology More common in females, with peak age of presentation between 40 and 60 years.  Pathology Perineal hernias are classified as anterior or posterior depending on their relationshi...
Article

Perineal membrane

The perineal membrane is a thin triangular horizontal layer of dense tough fascia in the perineum the dividing the urogenital triangle into the superficial (inferior) and deep (superior) perineal pouches. It attaches to the inferior margins of the ischiopubic rami, enclosing the anterior portio...
Article

Perineum

The perineum is a diamond shaped region below the pelvic diaphragm and is divided by an imaginary line drawn between the ischial tuberosities into anteriorly the urogenital triangle and posteriorly the anal triangle. Gross anatomy The perineum is bounded by the pubis anteriorly, the ischial tu...
Article

Peripancreatic pseudoaneurysm

Peripancreatic pseudoaneurysm refers to the formation of a pseudoaneurysm around the pancreatic gland. It is a rare but potentially lethal complication 5. Epidemiology Formation of pseudoaneurysm can occur in as many as 10% of cases of pancreatitis. The time interval is variable, ranging from ...
Article

Periportal free gas sign

The periportal free gas sign has been described as being strongly suggestive for upper gastrointestinal hollow viscus perforation. See also bowel perforation (summary) pneumoperitoneum
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Perirenal fascia

The perirenal fascia is a dense, elastic connective tissue sheath that envelops each kidney and adrenal gland together with a layer of surrounding perirenal fat forming the perirenal space. It is a multi-laminated structure which is fused posteromedially with the muscular fasciae of the psoas a...
Article

Perirenal space

The perirenal space is the largest of the three divisions of the retroperitoneum and is the most easily identified. It contains the kidneys, renal vessels and proximal collecting systems, adrenal glands and an adequate amount of fat to allow identification on CT scanning. The space is surrounde...

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