Articles
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16,860 results found
Article
Medical abbreviations and acronyms (N)
This article contains a list of commonly used medical abbreviations and acronyms that start with the letter N and may be encountered in medicine and radiology (please keep the main list and any sublists in alphabetic order).
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R ...
Article
Lipoma
Lipomas are benign tumors composed of mature adipocytes. They are the most common soft tissue tumor, seen in ~2% of the population.
Epidemiology
Patients typically present in adulthood (5th-7th decades).
Associations
In some cases, multiple lipomas are associated with syndromes and other di...
Article
Nevoid hyperkeratosis of the nipple and the areola
Nevoid hyperkeratosis of the nipple and the areola (NHNA) is a rare, idiopathic, and benign dermatological condition of the nipple and areola.
Epidemiology
Most often seen in females of reproductive age, especially during the 2nd and 3rd decades of life. Less than 70 cases have been reported t...
Article
Monochorionic monoamniotic twin pregnancy
A monochorionic monoamniotic (MCMA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac, a single amniotic sac, and, in general, a single yolk sac.
Epidemiology
It accounts for the minority (~5%) of monozygotic twin pregnancies and ~1-2% of a...
Article
Spinal epidural venous plexus congestion
Spinal epidural venous plexus congestion or dilatation is typically a complication of other pathologies.
Clinical presentation
Radiculopathy caused by the dilated epidural veins is not uncommon 1. More severe symptoms such as cauda equina compression syndrome have been reported 6, 7.
Patholo...
Article
Schneiderian papilloma
Schneiderian papillomas, also known as sinonasal papillomas, are benign sinonasal tumors that arise from the Schneiderian epithelium of the nasal cavity and paranasal sinuses.
Epidemiology
Schneiderian papillomas account for ~2.5% (range 0.4-4.7%) of sinonasal tumors 2.
Pathology
The WHO cl...
Article
Placental site trophoblastic tumor
Placental site trophoblastic tumors (PSTT) are rare and one of the least common (~0.2% 7) forms of gestational trophoblastic disease.
Epidemiology
Placental site trophoblastic tumors typically occur in women of reproductive age with an average age of ~30 years. They may occur after a normal pr...
Article
Craniovertebral junction anomalies
Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to an acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression, and obstructive hydrocephalus.
Pathology
The craniovertebral junction ...
Article
Bone marrow
Bone marrow is ubiquitous throughout the skeleton, primarily composed of hematopoietic cells and fat cells between bony trabeculae and fibrous retinacula. It performs numerous physiological functions and dynamically changes during normal aging and in response to stressors and pathology. Although...
Article
Gastric lymph node stations
The gastric lymph node stations were originally divided into 16 groups, as proposed by the Japanese Research Society for Gastric Cancer in 1973.
Gross anatomy
There are three major groups of lymph drainage from the stomach, namely, left gastric, gastroepiploic, and pyloric nodes 4, as shown in...
Article
Diffuse hepatic steatosis (grading)
Grading of diffuse hepatic steatosis on ultrasound has been used to communicate to the clinician about the extent of fatty changes in the liver.
Grading using ultrasound B-mode
grade I: diffusely increased hepatic echogenicity but periportal and diaphragmatic echogenicity is still appreciable...
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Vagal schwannoma
Vagal schwannomas are uncommon benign masses that can occur anywhere along the course of the vagus nerve but most commonly occur in the cervical region.
Epidemiology
Most commonly occurs in the 3rd to 5th decades. No sex predilection 3.
Clinical presentation
Patients may be asymptomatic. Whe...
Article
Pituitary macroadenoma
Pituitary macroadenomas are the most common suprasellar mass in adults, and responsible for the majority of transsphenoidal hypophysectomies. They are defined as pituitary adenomas greater than 10 mm in size and are approximately twice as common as pituitary microadenomas.
On imaging, they usu...
Article
Sinding-Larsen-Johansson disease
Sinding-Larsen-Johansson disease, also known as Sinding-Larsen disease or Larsen-Johansson syndrome, affects the proximal end of the patellar tendon as it inserts into the inferior pole of the patella. It represents a chronic traction injury of the immature osteotendinous junction. It is a close...
Article
Posterior ciliary arteries
The posterior ciliary arteries are usually paired branches arising from the ophthalmic artery, one medial and one lateral, each giving off a number of branches that supply the uvea 1.
Close to the optic nerve, are the short posterior ciliary arteries, usually numbering 16-20; these supply the p...
Article
Thyroid-associated orbitopathy
Thyroid-associated orbitopathy, also known as thyroid-associated ophthalmopathy or thyroid eye disease, is the most common cause of proptosis in adults and is most frequently associated with Graves disease. On imaging, it is characterized by bilateral and symmetrical enlargement of the extraocul...
Article
Persistent carotid-vertebrobasilar anastomoses
The persistent carotid-vertebrobasilar anastomoses are variant anatomical arterial communications between the anterior and posterior circulations due to abnormal embryological development of the vertebrobasilar system. They are named, with the exception of the proatlantal artery, using the crani...
Article
Skull vault osteoma
Skull vault osteomas are benign primary bone tumors that are commonly incidentally discovered. They are less common than paranasal sinus or mandibular osteomas.
Clinical presentation
Skull vault osteomas are typically asymptomatic but may present as painless, slow-growing masses or with compr...
Article
Caudate nucleus
Caudate nuclei are paired nuclei which along with the globus pallidus and putamen are referred to as the corpus striatum, and collectively make up the basal ganglia. The caudate nuclei have both motor and behavioral functions, in particular maintaining body and limb posture, as well as controlli...
Article
Pituitary gland
The pituitary gland (a.k.a. hypophysis cerebri), together with its connections to the hypothalamus, acts as the main endocrine interface between the central nervous system and the rest of the body.
Gross anatomy
The pituitary gland sits atop the base of the skull in a concavity within the sph...
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