Items tagged “refs”
2,959 results found
Article
Racing car sign (callosal dysgenesis)
The racing car sign refers to widely spaced lateral ventricles due to agenesis of the corpus callosum with intervening Probst bundles. Appearances on axial MRI or CT are reminiscent of a Formula One car seen from above, with the tyres represented by the widely-spaced frontal horns, and the dilat...
Article
Ramsay Hunt syndrome
Ramsay Hunt syndrome, also known as herpes zoster oticus or Ramsay Hunt syndrome type 2, is shingles of the facial nerve. It is due to reactivation of the varicella zoster virus (VZV) in the geniculate ganglion.
Clinical presentation
Ramsay Hunt syndrome classically presents with a triad of 3,...
Article
Rhabdomyosarcoma (staging)
Rhabdomyosarcoma staging is based on the Lawrence/Gehan staging system, which comprises of a combination of pretreatment staging and postoperative clinical grouping.
Stage
stage I: orbit, eyelid, head and neck (excluding parameningeal), genitourinary (non-bladder, non-prostate), N0 or 1, M0
s...
Article
Rheumatic fever
Rheumatic fever is an illness caused by an immunological reaction following group A streptococcal infection.
Epidemiology
Risk factors include:
children and adolescents aged 5 to 15 years
developing nations where antibiotic prescription is low 1
poverty, overcrowding
Clinical presentation...
Article
Ring artifact
Ring artifacts are a CT phenomenon that occurs due to the miscalibration or failure of one or more detector elements in a CT scanner. Less often, it can be caused by insufficient radiation dose or contrast material contamination of the detector cover 2.
Features
This artifact usually occurs i...
Article
Rotator cuff
The rotator cuff is a group of four muscles and their tendons, important in stabilizing the glenohumeral joint:
supraspinatus: abduction
infraspinatus: external rotation
teres minor: external rotation
subscapularis: internal rotation
Other structures that stabilize the glenohumeral joint in...
Article
Rotator cuff interval
The rotator cuff interval is a triangular space between the tendons of subscapularis and supraspinatus and the base of the coracoid process.
Gross anatomy
The combination of the coracohumeral ligament and superior glenohumeral ligament has a complex relationship with the long head of biceps te...
Article
Rotator cuff tear grading (MRI)
One method of grading rotator cuff tears on MRI is as follows:
grade 0: normal
grade I: increased T2 signal with normal morphology
grade II: increased T2 signal with abnormal morphology (thickening, or irregularity of the tendon)
grade III: defined tear (e.g. partial or full-thickness, compl...
Article
Salter-Harris fracture classification (mnemonic)
Useful mnemonics for remembering the Salter-Harris classification system are:
SALTR
SMACK
SMETI
Fortunately, this is also the order of prognosis (from best to worse)
Mnemonics
SALTR
S: slipped (type I)
A: above or away from joint (type II)
L: lower (type III)
T: through or transverse o...
Article
Oral cavity carcinoma (staging)
Oral cavity carcinoma staging refers to TNM staging of carcinomas involving the oral cavity. The vast majority of applicable cases are squamous cell carcinomas, but other epithelial and minor salivary gland cancers are also included. The following article reflects the 8th edition published by th...
Article
Saber-sheath trachea
Saber-sheath trachea refers to a diffuse coronal narrowing of the intrathoracic portion of the trachea with the concomitant widening of the sagittal diameter. It is not uncommon and is pathognomonic for chronic obstructive pulmonary disease (COPD) 1.
The sagittal:coronal diameter is over 2:1 2...
Article
Shenton line
Shenton line is an imaginary curved line drawn along the inferior border of the superior pubic ramus (superior border of the obturator foramen) and along the inferomedial border of the neck of femur. This line should be continuous and smooth1.
Interruption of the Shenton line can indicate (in...
Article
Sigmoid plate
The sigmoid plate is variously described as the plate of bone between the jugular bulb and the middle ear cavity (as shown in first image) or more generally as the thin bone separating the sigmoid sinus from adjacent structures (especially mastoid air cells). In the case of the former, the struc...
Article
Sinotubular junction
The sinotubular junction (STJ) is the region of the ascending aorta between the aortic sinuses (of Valsalva) and where the normal tubular configuration of the aorta is attained. It marks the junction of the aortic root and ascending aorta.
Article
Small bowel
The small bowel (or small intestine) is the section of bowel between the stomach and the colon. It has distinctive mucosal folds, valvulae conniventes, and is made up of three functional units:
duodenum
jejunum
ileum
Terminology
Although anatomically it is stated that the duodenum forms the...
Article
Solitary bone cyst of the mandible
Solitary bone cysts of the mandible (also known as traumatic bone cyst of the jaw, hemorrhagic cyst of the mandible, extravasation cyst, progressive bone cavity or unicameral bone cyst) are an uncommon nonepithelial lined lucent mandibular lesion. It is one of a myriad of potential mandibular le...
Article
Spetzler-Martin arteriovenous malformation grading system
The Spetzler-Martin arteriovenous malformation (AVM) grading system allocates points for various angiographic features of intracranial arteriovenous malformations to give a score that predicts the morbidity/mortality risk of surgery 5.
Grading
The grading system requires correlation between C...
Article
Spinal fractures
Spinal fractures are usually the result of significant trauma to a normally formed skeleton or the result of trauma to a weakened spinal column. Examples include:
Jefferson fracture: ring fracture of C1
hangman fracture: bilateral pedicle or pars fracture of C2
dens fracture
flexion teardrop...
Article
Spinal epidural injection
Epidural spinal injections are one of the more frequently performed spinal interventional procedures. Three approaches to the epidural space exist:
caudal epidural injection (via the sacral hiatus)
interlaminar epidural injection
cervical interlaminar epidural injection
lumbar in...
Article
Spinal epidural mass
The differential diagnosis for a spinal epidural mass includes:
epidural metastasis
epidural abscess
herniated nucleus pulposus
epidural hematoma
epidural arteriovenous malformation
epidural angiolipoma
epidural lipomatosis
extramedullary hematopoiesis
spinal schwannoma
spinal meningio...