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.

249 results found
Article

N-acetylaspartate (NAA) peak

N-acetylaspartate (NAA) is one of the more important compounds assessed on MR spectroscopy, and resonates at 2.0 ppm chemical shift.  NAA is the acetylated form of the amino acid, aspartate, which is found in high concentrations in neurons and is a marker of neuronal viability. It is therefore ...
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N-acetylcysteine

N-acetylcysteine (NAC) if often used as a prophylaxis against contrast-induced nephropathy. Protocols for administration vary widely from institution to institution and the true efficacy is still controversial. A typical protocol is [1-2]: 600 mg acetylcysteine twice daily on the day of the ex...
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Nabothian cyst

Nabothian cysts, also known as a retention cysts of the cervix 11, are non-neoplastic cystic lesions that occur in relation to the uterine cervix. Epidemiology They are common and some reports suggest that they may be seen in up to 12% of routine pelvic MRI scans 2. Clinical presentation The...
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Naclerio V sign

The Naclerio V sign is a sign described on the plain film in patients with a pneumomediastinum occurring often secondary to an oesophageal rupture.  It is seen as a V-shaped air collection. One limb of the V is produced by mediastinal air outlining the left lower lateral mediastinal border. The...
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Naegele's formula

The Naegele's formula is simple arithmetic method for calculating the EDD (estimated date of delivery) based on the LMP (last menstrual period). To the date of the first day of the LMP (e.g. 22nd June 2008): add seven days (i.e 29th) subtract 3 months (i.e March) add one year (i.e 2009)
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Nager syndrome

The Nager syndrome (also known as acrofacial dysostosis) is a rare congenital syndrome primarily characterised by facial and skeletal features Pathology Genetics There may be agenetic defect localized to chromosome 9q32. Most cases are thought to be sporadic . Occasional autosomal recessive a...
Article

Nail-patella syndrome

Nail-patella syndrome, also known as Fong disease or osteo-onychodysostosis, is a rare autosomal dominant condition which results from symmetrical mesodermal and ectodermal abnormalities. Clinical presentation Clinically, the key feature is absent/hypoplastic nails from birth. Individuals may ...
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Naked facet sign

The naked facet sign (also known as the hamburger sign or reverse hamburger bun sign) refers to the CT appearance of an uncovered vertebral articular facet when the facet joint is dislocated, most often in cases of locked facet.  This CT sign is characteristic of a flexion-distraction injury an...
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Named fractures

Named fractures are usually eponymous or occupational. The simplest way of spiting them up is by body area: spinal fractures facial fractures upper extremity fractures pelvic fractures lower extremity fractures
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Names

Using names on Radiopaedia.org is common when describing procedures and the history surrounding eponymous names. When referring to a person, do not use punctuation in the name and use spaces between initials. For example: Dr R F Player (correct) Dr. R. F. Player (incorrect) Dr RF Player (inc...
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Napkin-ring sign (heart)

The napkin-ring sign (heart) is a recently described sign encountered on CT coronary angiogram (coronary CTA) performed on modern MDCT. It has been shown to possess a high predictive value in predicting future cardiac events and is considered one of the imaging correlates of an unstable plaque. ...
Article

Narrow fetal thorax

A narrow fetal thorax on antenatal ultrasound can be present with a number of anomalies which include: achondrogenesis camptomelic dysplasia homozygous achondroplasia Jarcho-Levin syndrome Jeune syndrome - asphyxiating thoracic dysplasia Russell-Silver dwarfism short rib polydactyly syndr...
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Narrowing of interpedicular distance

The interpedicular (IP) distance which is the distance measured between the pedicles on frontal / coronal imaging can be narrowed in a number of situations  Causes include achondroplasia 3 thanatophoric dysplasia 2 See also  widening of interpedicular distance  See reference 1 for an old b...
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Nasal bone

The nasal bones are paired oblong upper central facial bones placed side by side between the frontal processes of the maxilla, jointly forming the nasal ridge. Gross anatomy The nasal bone has two surfaces: external surface attaches the procerus and nasalis muscles internal, which is transve...
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Nasal bone fracture

Nasal bone fractures are the most common type of facial fractures, accounting for ~45% of facial fractures, and are often missed when significant facial swelling is present.  Clinical presentation Unsurprisingly, nasal bone fractures occur when the nose impacts against a solid object (e.g. fis...
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Nasal cavity

The nasal cavity forms part of the aerodigestive tract. Gross anatomy The nasal cavity is formed by 1: anteriorly: nasal aperture laterally: inferior, middle and superior nasal conchae or turbinates superiorly: cribiform plate of the ethmoid bone inferiorly: palatal processes of the maxill...
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Nasal concha

The nasal conchae are long, narrow curled shelves of bone that protrude into the nasal cavity. The superior, middle and inferior conchae divide the nasal cavity into three groove-like air passages. The conchae are located laterally in the nasal cavity and covered by pseudostratified columnar, c...
Article

Nasal encephalocoele

Nasal encephalocoeles are in most cases a form of neural tube defect particularly common in Southeast asia. They are are herniation of cranial content through a bony defect in the anterior skull base into the nasal area. The term is variably used, but generally encompasses both frontoethmoidal ...
Article

Nasal glioma

Nasal gliomas, also know as nasal glial heterotopia, are a rare congenital lesion composed of dysplastic glial cells which have lost their intracranial connections and present as an extranasal or intranasal mass.  Epidemiology Nasal gliomas are rare congenital lesions. These masses occur spora...
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Nasal septal perforation

Nasal septal perforation may affect either the bony, or cartilaginous septum. Most commonly it affects the anterior septal cartilaginous area although with syphilis it characteristically affects the bony septum. Clinical presentation Symptoms include a nasal discharge, nasal congestion (loss o...
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Nasal septum perforation (mnemonic)

A not-very-useful mnemonic for the causes of nasal septum perforation is: Say Water Coke Syrup Sugarwater Lemonade or Say Nothing  Mnemonic S: sarcoidosis W: Wegener granulomatosis C: cocaine S: syphilis S: surgery L: leprosy or say N: non-Hodgkin T-cell lymphoma (NHL)
Article

Nasion

The nasion is the midline bony depression between eyes where the frontal and two nasal bones meet, just below the glabella. It is also known as the bridge of the nose. It is one of the skull landmarks, craniometric points for radiological or anthropological skull measurement.
Article

Naso-orbitoethmoid (NOE) complex fracture

Naso-orbitoethmoid (NOE) fractures (also known as orbitoethmoid or nasoethmoidal complex fractures) are fractures which involve the central upper midface. Pathology Naso-orbitoethmoid fractures are caused by a high-impact force applied anteriorly to the nose and transmitted posteriorly through...
Article

Nasociliary nerve

The nasociliary nerve is the intermediate branch of the ophthalmic division of the trigeminal nerve. Gross anatomy The nasociliary nerve divides off the ophthalmic division just before entering the orbit through the superior orbital fissure and through the tendinous ring between the inferior a...
Article

Nasogastric tube positioning

Assessment of nasogastric (NG) tube positioning is a key competency of all doctors as unidentified malpositioning may have dire consequences, including death. The ideal position should be in the sub-diaphragmatic position in the stomach - identified on a plain chest radiograph as overlying the ...
Article

Nasolabial cyst

Nasolabial cyst (also known as nasoalveolar cyst or Klestadt`s cyst) is a rare non-odontogenic, soft-tissue, developmental cyst occurring inferior to the nasal alar region. The cyst is derived from epithelial cells retained in the mesenchyme after fusion of the medial and lateral nasal processes...
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Nasolacrimal drainage apparatus

The nasolacrimal (drainage) apparatus consists of: lacrimal canaliculi lacrimal sac nasolacrimal duct Tears produced by the lacrimal gland, accessory lacrimal glands of Krause Wolfring and Zeis, and Meibomian glands track medially along the eyelid margins and collect at the lacrimal lake at ...
Article

Nasolacrimal duct

The nasolacrimal duct is the terminal part of the nasolacrimal apparatus. Gross anatomy Then nasolacrimal duct is the inferior continuation of the lacrimal sac and is ~17 mm in length in total. There are two parts to the nasolacrimal duct: intraosseous part (12 mm): lies within the nasolacrim...
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Nasolacrimal duct mucocele

Nasolacrimal duct mucocele represents cystic dilatation of the nasolacrimal apparatus secondary to proximal +/- distal obstruction of the nasolacrimal duct. Clinical presentation Presentation is common early in infancy, typically 4 days to 10 weeks. Infants present with small round bluish medi...
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Nasolacrimal tumours

Nasolacrimal tumours, in other words tumours involving the nasolacrimal drainage apparatus, are uncommon, and have a variety of histologies. Clinical presentation Clinical presentation of nasolacrimal tumours are typically fairly non-specific, often resulting in delayed diagnosis 1. Typical pr...
Article

Nasomaxillary suture

This suture forms the fissure between the frontal process of maxilla and the lateral border of the nasal bone. The nasomaxillary sutures are paried.
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Nasopalatine nerve

The nasopalatine nerve (also known as the long sphenopalatine nerve) is a branch of the maxillary division of the trigeminal nerve and contributes to the pterygopalatine ganglion. Gross anatomy The nasopalatine nerve divides off the maxillary division just after emerging from the foramen rotun...
Article

Nasopharyngeal carcinoma

Nasopharyngeal carcinomas (NPC) are the most common primary malignancy of the nasopharynx. It is of squamous cell origin, some types of which are strongly associated with the Epstein-Barr virus (EBV). Epidemiology Nasopharyngeal carcinoma accounts for ~70% of all primary malignancies of the na...
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Nasopharyngeal carcinoma (staging)

Nasopharyngeal carcinoma staging uses the TNM staging system with derived stage groupings.  TNM staging Primary tumour (T) Tx: primary tumour cannot be assessed T0: no evidence of primary tumour Tis: carcinoma in situ T1: tumour is confined to the nasopharynx T2: tumour extends to soft ti...
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Nasopharyngeal choristoma

A nasopharyngeal choristoma is a rare, non-neoplastic mass (type of choristoma) typically located in the lateral aspect of the nasopharynx without intracranial extension. These lesions are composed of fibrovascular tissue and fat. Resection is curative. Differential diagnosis nasopharyngeal ca...
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Nasopharyngeal mass (mnemonic)

A mnemonic for causes of nasopharyngeal masses is: SAIL Mnemonic S: squamous cell carcinoma A: antrachoanal polyp I: inverted papilloma L: lethal midline granuloma
Article

Nasopharynx

The nasopharynx forms part of the pharynx, being the continuation of the nasal cavity superiorly, and the oropharynx inferiorly.  Gross anatomy Boundaries anteriorly: posterior nares and posterior margin of nasal septum 1,2 inferiorly: soft palate 2 superiorly: basi-sphenoid and basi-occipu...
Article

Nasu Hakola disease

Nasu Hakola disease, also known as polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, is a rare inherited neuropsychiatric disorder which in addition to cognitive impairment also is demonstrates bone cysts.   Epidemiology Nasu Hakola disease is inherited as an autoso...
Article

National Institutes of Health Stroke Scale (NIHSS)

The National Institutes of Health Stroke Scale (NIHSS) is a score calculated from 11 components and is used to quantify the severity of strokes. The 11 components are:  level of consciousness (1a: 0-3, 1b: 0-2 and 1c: 0-2) best gaze (0-2) visual fields (0-3) facial palsy (0-3) arm motor (0-...
Article

Navicular

The navicular bone is found in the midfoot and is one of the tarsal bones. It's structure resembles that of a boat. It is the last bone of the foot to ossify fully 1. Summary location: lies within the medial aspect of the midfoot relations: the talus bone, cuboid bone and the three cuneiform ...
Article

Near drowning pulmonary oedema

Near drowning pulmonary oedema is considered an aetiological subtype of non cardiogenic pulmonary oedema. It can occur with both salt water and fresh water near-drowning. Pathology It is thought to result from the inhalation of either fresh water or sea water resulting in lung damage and a ven...
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Neck dissection classification

There are several types of neck dissections which can classified as follows: Radical neck dissection Radical neck dissection is considered to be the standard basic procedure for cervical lymphadenectomy. All other procedures represent one or more alterations of this procedure. The dissection i...
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Neck tongue syndrome

Neck tongue syndrome (NTS) is rare and comprises altered sensation in one side of the tongue aggravated by neck movement, with ipsilateral neck pain 1.  Epidemiology NTS is seen in a wide range of ages but is more commonly reported in older children and young adults 1-3.  Clinical presentatio...
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Necrobiotic pulmonary nodules

Necrobiotic pulmonary nodules are sterile cavitating lung nodules associated with inflammatory bowel disease (more often with ulcerative colitis than with Crohn's disease) and rheumatoid arthritis.  Pathology Histologically, necrobiotic nodules consist of a core of fibrinoid necrosis and steri...
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Necrotising enterocolitis

Necrotising enterocolitis (NEC) is the most common gastrointestinal condition in premature neonates, and continues to have significant mortality and morbidity. Epidemiology NEC usually develops 2-3 days following birth, with 90% developing within the first 10 days of life 4. The incidence is i...
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Necrotising enterocolitis (staging)

Necrotising enterocolitis (NEC) can be staged into three groups, helping to guide appropriate treatment. In general, stage I and II are managed medically whereas stage III is managed surgically. stage I clinical signs lethargy, temperature instability, apnoea, bradycardia emesis, abdominal d...
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Necrotising fasciitis

Necrotising fasciitis refers to a rapidly progressive and often fatal infection of soft-tissue fascia deep to the skin but superficial to the muscles. Epidemiology Necrotising fasciitis is relatively rare, although its prevalence is thought to be rising due an increase in the number of immunoc...
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Necrotising otitis externa

Necrotising otitis externa (NOE), also known as malignant otitis externa, is a severe invasive infection of the external auditory canal (EAC) which can spread rapidly to involve the surrounding soft tissue, adjacent neck spaces and skull base.  Pathology Predisposing conditions for NOE include...
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Necrotising pancreatitis

Necrotising pancreatitis (NP) represents the severe form of pancreatitis. It is considered a subtype of acute pancreatitis as necrosis usually tends to occurs early, within the first 24-48 hours, but can also rarely occur with subacute forms. A key feature is a significant amount of pancreatic ...
Article

Necrotising pneumonia

Necrotising pneumonia (NP) refers to a pneumonia characterised by the development of the necrosis within infected lung tissue. While the term has sometimes been used synonymously with a cavitating pneumonia in some publications 2, not all necrotising pulmonary infections may be complicated by ca...
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Necrotising sarcoid granulomatosis

Necrotising sarcoid granulomatosis (NSG) is a rare systemic disease, characterised by sarcoid-like granuloma formation, vasculitis and variable degrees of necrosis. It is sometimes classified under the group of pulmonary angiitis and granulomatois. Epidemiology It typically affects affecting m...
Article

Necrotising sialometaplasia

Necrotising sialometaplasia is a benign inflammatory condition of the salivary gland remnants or elements, which is usually self-limiting.  It is most commonly found in the palate.  Epidemiology Most patients are more than 40 years of age, with a male:female ratio of 2:1. It is rarely seen in ...
Article

Neer classification of proximal humeral fractures

The Neer classification of proximal humeral fractures is probably the most frequently used along with the AO classification of proximal humeral fractures. Even if an exact knowledge of this classification system is beyond the everyday use of many radiologists, the terminology and factors which i...
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Negative enhancement integral

The negative enhancement integral in MR perfusion is used to calculate the relative cerebral blood volume (rCBV).  It represents the area described by the baseline and the signal loss due to passage of contrast bolus in tissue. 
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Negative predictive value

Negative predictive value of a test/investigation is defined as the proportion of patients with negative results being truly disease free. Calculation Negative predictive value = true negatives detected / total negative results (where "total negative results" = true negative + false negative)...
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Negative questions (multiple choice questions)

Negative questions, also known as odd-one-out questions are a type of multiple choice question in which the correct answer is the one that is false, surrounded by true distractors. For example:  Question: Which of the following statements about Onodi cells (sphenoethmoidal air cells) is INCORRE...
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Negative ulnar variance

Negative ulnar variance describes a state where the ulna is abnormally shortened compared to the radius and plays an important role in wrist pathology. There is a significant association between negative ulnar variance and Kienböck disease, although the majority of people with negative ulnar va...
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Neimeier classification of gall bladder perforation

This classification was proposed by Neimeier and later modified by Anderson et al in 1987, which at the time of writing (July 2016) remains the most widely accepted classification for gall bladder perforation. According to this classification, there are three main clinical sub types..  A fourth...
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Neonatal appendicitis

Neonatal appendicitis is rare, presumably in part due to the short funnel shape to the appendix at that age. Symptoms are non-specific and may mimic necrotising enterocolitis. 
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Neonatal bilious vomiting

Neonatal bilious vomiting has a relatively narrow differential - those conditions that cause intestinal obstruction, but do so distal to the ampulla of Vater.  As such, the list includes: malrotation with midgut volvulus duodenal atresia jejunoileal atresia meconium ileus necrotizing entero...
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Neonatal chest radiograph in the exam setting

The neonatal chest radiograph in the exam setting may strike fear into the heart of many radiology registrars, but it need not! There are only a limited number of diagnoses that will be presented on such films and they are often highlighted by the history. Gestation First of all, have a look ...
Article

Neonatal encephalopathy

Neonatal encephalopathy is a clinical syndrome referring to signs and symptoms of abnormal neurological function in the first few days of life in a neonate born at or beyond 35 weeks of gestation. It is described as difficulty with initiating and maintaining respiration, depression of tone and r...
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Neonatal herpes simplex encephalitis

Neonatal herpes simplex encephalitis is caused by vertical transmission of infection during passage from birth canal with diffuse cerebral involvement within the first month after birth; in contrast to adult herpes simplex encephalitis, it is commonly related to HSV-2.  Epidemiology The incide...
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Neonatal hydronephrosis

Neonatal hydronephrosis is most commonly diagnosed antenatally as fetal pylectasis. Pathology Aetiology pelvi-ureteric junction (PUJ) obstruction (50% of cases 1,6) vesicoureteric reflux (~20% of cases 5) posterior urethral valves (~10 6) vesico-ureteric junction (VUJ) obstruction megacys...
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Neonatal hypoxic-ischaemic encephalopathy

Neonatal hypoxic-ischaemic encephalopathy (HIE) is the result of a global hypoxic-ischaemic brain injury in a term neonate, usually after asphyxia. Terminology It is important to remember that neonatal encephalopathy may result from a variety of conditions and hypoxic-ischaemic brain injury is...
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Neonatal lines and tubes

Neonatal lines and tubes are widely used in the NICU (neonatal intensive care unit) in the management of critically ill neonates. Examples include: nasogastric tube endotracheal tube central venous line umbilical artery catheter umbilical vein catheter Nasogastric tube The NG tube serves ...
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Neonatal pneumonia

Neonatal pneumonia refers to inflammatory changes of the respiratory system caused by neonatal infection. Epidemiology It is one of the leading causes of significant morbidity and mortality in developing countries. Neonatal pneumonia accounts for 10% of global child mortality. At the time of w...
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Neonatal pneumoperitoneum

The causes of neonatal pneumoperitoneum are different from adult pneumoperitoneum and include: perforated hollow viscus necrotising enterocolitis (NEC): most common meconium ileus in cystic fibrosis Hirschsprung disease intestinal atresia or web peptic ulcer disease iatrogenic intubation...
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Neonatal pneumothorax

Neonatal pneumothorax describes pneumothoraces occurring in neonates. It is a life threatening condition, associated with high morbidity and mortality. The diagnosis is a challenge especially when the amount of air is small and may accumulate along the anterior or medial pleural space. Epidemio...
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Neonatal respiratory distress (causes)

Causes of neonatal distress can be broadly split into intrathoracic, extrathoracic and systemic: Intrathoracic Medical respiratory distress syndrome (RDS) transient tachypnoea of the newborn (TTN) meconium aspiration syndrome bronchopulmonary dysplasia (BPD) patent ductus arteriosus (PDA)...
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Neoplasms of the appendix

There are number of neoplasms that can involve the appendix, some of which are peculiar to this site.
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Neoplasms of the cauda equina (differential)

The differential diagnosis for masses of the cauda equina region is often considered separately to the remainder of the spinal cord. It is often difficult to determine whether masses in this region are intramedullary or intradural-extramedullary. Most common tumours myxopapillary ependymoma b...
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Neoplasms of the spinal canal

Neoplasms of the spinal canal encompass a range of tumours which arise from or involve the spinal cord, theca and nerves. Pathology These can be divided according to the tissue/structure of origin. Tumours of vertebral bodies are discussed separately: see vertebral body tumours.  Spinal cord ...
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Neostriatum

Neostriatum is the name given to the caudate nucleus and the putamen (the putamen is the outer layer of the lentiform nucleus). Terminology The term is sometimes abbreviated to striatum, however, this should be distinguished from corpus striatum (which is the caudate nucleus in addition to the...
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Nephroblastomatosis

Nephroblastomatosis refers to diffuse or multifocal involvement of the kidneys with nephrogenic rests (persistent metanephric blastema). Epidemiology Nephrogenic rest are found incidentally in 1% of infants. Pathology Nephrogenic rests are foci of metanephric blastema that persist beyond 36 ...
Article

Nephrocalcinosis

Nephrocalcinosis, previous known as Anderson-Carr kidney or Albright's calcinosis, refers to the deposition of calcium salts in the parenchyma of the kidney. It is divided into several types, with differing aetiologies, based on the distribution: medullary nephrocalcinosis: 95% cortical nephro...
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Nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy, is a complication of gadolinium-based contrast agents used in imaging studies. It is characterised by "firm, erythematous, and indurated plaques of the skin associated with subcutaneous oedema" 1. Eventually, f...
Article

Nephroptosis

Nephroptosis, also known as floating or wandering kidney and ren mobilis, refers to the descent of the kidney more than 5 cm or two vertebral bodies when the patient moves from a supine to upright position during IVU 1-2. Displacement can also occur medially across the midline, so-called medial...
Article

Nephrostomy

Nephrostomy is a common urologic or interventional radiology procedure in which a tube/catheter is introduced into the renal collecting system (usually the renal pelvis). Nephrostomies can either be "open" nephrostomy: after a urological surgical procedure, such as a UPJ stone removal these t...
Article

Nephrotic syndrome

Nephrotic syndrome (NS) results from loss of plasma proteins in the urine and characterised by hypoalbuminemia, hyperalbuminuria, hyperlipidemia, and oedema. It may be caused by primary (idiopathic) renal disease or by a variety of secondary causes. Clinical presentation Patients present with ...
Article

Nerve entrapment at elbow and wrist (differential)

Nerve entrapment at elbow and wrist can occur a number of distinct anatomical locations and result in several clinical syndromes, including: Common carpal tunnel syndrome cubital tunnel syndrome Less common pronator syndrome radial entrapment neuropathy radial tunnel syndrome posterior i...
Article

Nerve injury classification

Nerve injury classification describes the various features of nerve injury on MRI with respect to pathological events. Classification neuropraxia grade I: there is increased T2/STIR signal in the nerve, however the muscle appears normal axonotmesis grade II: increased T2/STIR signal in ne...
Article

Nerve to internal obturator and superior gemellus

The nerve to obturator internus and superior gemellus is formed from the anterior (ventral) divisions of the L5, S1 and S2 nerve roots of the sacral plexus. The nerve supplies the obturator internus and superior gemellus muscles as well as the fascia of the lateral side wall of the ischioanal fo...
Article

Nerve to medial pterygoid

The nerve to medial pterygoid or medial pterygoid nerve is a branch of the mandibular division of the trigeminal nerve. Gross anatomy The nerve to medial pterygoid divides off the mandibular division just below the foramen ovale and just before it branches into anterior and posterior divisons....
Article

Nerve to mylohyoid

The nerve to mylohyoid or mylohyoid nerve is a motor branch of the inferior alveolar nerve, a branch of the mandibular division of the trigeminal nerve. Gross anatomy The nerve to mylohyoid arises from the inferior alveolar nerve just before it enters the mandibular foramen. It does not enter ...
Article

Nerve to piriformis

Nerve to the piriformis muscle also known as piriformis nerve arises from the S1 and S2 nerve roots of the sacral plexus. The nerve supplies the piriformis muscle.  Gross anatomy Origin The nerve to the piriformis muscle arises from the sacral plexus. The nerve branches from the posterior div...
Article

Nerve to quadratus femoris and inferior gemellus

The nerve to quadratus femoris and inferior gemellus is formed from the anterior (ventral) divisions of the L4, L5 and S1 nerve roots of the sacral plexus. The nerve supplies the quadratus femoris and inferior gemellus muscles as well as providing an articular branch to the hip joint.   Gross a...
Article

Nerve to stapedius

The nerve to stapedius arises from the facial nerve to supply the stapedius muscle. The branch is given off in the facial nerve's mastoid segment, as it passes posterior to the pyramidal process. Damage to this branch with resulting paralysis of stapedius leads to hypersensitivity to loud noise...
Article

Nervus intermedius

The nervus intermedius, also known as nerve of Wrisberg, is a part of the facial nerve (CN VII) which contains somatic sensory, special sensory, and visceral motor (secretomotor) fibres 1. Gross anatomy Nuclei superior salivary nucleus parasympathetic supply to the lacrimal and major salivar...
Article

Nervus spinosus

The nervus spinous (which is also known as the meningeal nerve of the mandibular nerve) is a branch of the mandibular division of the trigeminal nerve which supplies the dura of the middle cranial fossa. Gross anatomy The nervus spinosus divides off the mandibular division just below the foram...
Article

Nervus terminalis

The nervus terminalis, also referred to as cranial nerve zero, cranial nerve XIII, zero nerve, nerve N or NT, is a previously unnumbered cranial nerve, most rostral of all cranial nerves. Gross anatomy It is a bilateral bundle of nerve fibres, which runs in the subarachnoid space from the medi...
Article

Net magnetisation vector

The net magnetisation vector (NMV) in MRI is the summation of all the magnetic moments of the individual hydrogen nuclei. In the absence of an external magnetic field, the individual magnetic moments are randomly oriented and since they are in opposition, the NMV is considered to be zero. If h...
Article

Neu-Laxova syndrome

Neu-Laxova syndrome is a lethal autosomal recessive multiple malformation syndrome with a heterogeneous phenotype. Clinical features The clinical spectrum can be quite wide and includes: dermal / cutaneous severe skin restriction ichthyosis decreased fetal movement marked intrauterine gro...

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