Teres major is one of the seven scapulohumeral muscles that act around the glenohumeral joint to facilitate shoulder movement.
origin: caudal two thirds of lateral border and inferior angle of scapula
insertion: medial border of the intertubercular groove, which is the crest of lesser...
Teres minor is one of the four muscles that make up the rotator cuff, the others being: supraspinatus, infraspinatus, and subscapularis.
origin: lateral border of the scapula
insertion: greater tuberosity of the humerus
innervation: axillary nerve (C5-6)
arterial supply: circumflex ...
The terminal bronchioles are a continuation of the bronchi and are the last divisions of the conducting airways.
Terminal bronchioles, are confusingly named, as they not the final branches but rather the distal bronchioles that do not bear alveoli. The first 19 divisions from ...
Each breast lobe is drained by a collecting duct terminating in the nipple. The collecting duct has several branches, which ends in a terminal ductal-lobular unit (TDLU), the basic functional and histopathological unit of the breast. The TDLU is composed of a small segment of the terminal duct a...
The differential diagnosis for a terminal ileitis is quite extensive, and includes:
inflammatory bowel disease
Crohn disease (most common)
backwash ileitis due to ulcerative colitis
The terminal ileum is the most distal segment of small bowel. It immediately precedes the small bowel's connection with the colon through the ileocaecal valve. It is of particular interest since a number of infectious and inflammatory processes preferentially involve the segment.
location: the ...
Terminal myelocystoceles are an uncommon form of spinal dysraphism representing marked dilatation of the central canal of the spinal cord, herniating posteriorly through a dorsal spinal defect. The result is a skin-covered mass in the lower lumbar region, consisting of an ependyma-lined sac.
The terminal tuft is the most distal part of a distal phalanx, and comprises of the flared bone distal to the shaft.
spade phalanx sign
terminal tuft masses
as it is close to the nail, pathology or injuries of one can affect the other
There is only a short list of terminal tuft masses, which can arise from the adjacent soft tissues and erode the terminal tuft as well as arising from the terminal tuft itself:
epidermal inclusion cyst: history of penetrating trauma
giant cell tumour of the tendon sheath: occur laterally
The terminal zones of myelination are located at the posterior aspect of the lateral ventricles (the peritrigonal regions) and are the only part of the cerebral white matter that may exhibit high T2 signal in a normal brain at 2 years of age, when myelination of cerebral white matter normally be...
The Terminologia Anatomica (TA) is the global standard for correct gross anatomical nomenclature in humans 1. The second edition was published in 2011 4.
The standard anatomical terms are from Latin and Ancient Greek roots. The English edition of the Terminologia Anatomica provides the accepte...
The terminology section of a standard article does not appear in all articles and is only required where clarification about terminology is required.
The terminology section is located immediately after the introduction, and before epidemiology.
This section will usually b...
There are numerous terms used in radiology that are worth knowing and this is list of some of them.
The terrible triad of the elbow is a severe elbow fracture-dislocation pattern and is so-called because it has poor medium-to-long term outcome.
Most commonly due to a fall onto an outstretched hand, not necessarily high-energy, with the arm in semi-flexion and supination...
The Terry Thomas sign refers to an increase in the scapholunate space on an AP radiograph of the wrist (or coronal CT). The increased distance indicates scapholunate dissociation (often with rotary subluxation of the scaphoid) due to ligamentous injury. There is no consensus as to what measureme...
Terson syndrome refers to vitreous haemorrhage associated with subarachnoid haemorrhage, however some authors include retinal haemorrhage as well. The syndrome is a poor prognostic marker in patients with subarachnoid haemorrhage.
Terson syndrome has been reported to occur in 13-5...
TERT promoter mutations affect the TERT promoter (located on the short arm of chromosome 5) which encodes for the hTERT component of telomerase, an enzyme which maintains and lengthens telomeres 1. Mutations that result in enhanced activity of telomerase, and therefore longer telomeres, can be i...
The tesla (symbol T) is the derived SI unit of magnetic flux density, which represents the strength of a magnetic field. One tesla represents one weber per square metre. The equivalent, and superseded, cgs unit is the gauss (G); one tesla equals 10,000 gauss.
As for all eponymous ...
Testicular abscess is usually a complication of severe epididymo-orchitis and needs to be distinguished from other testicular pathology that may present with similar clinical or imaging features.
The majority of patients develop a testicular abscess as a result of untreated or se...
Testicular adrenal rests are a rare cause of a testicular mass.
Testicular adrenal rests can be known by a variety of terms 2:
testicular adrenal rest tumour (TART)
testicular adrenal rest tissue
testicular tumour of the adrenogenital syndrome
testicular adrenal-like tissue
Testicular and scrotal ultrasound is the primary modality for imaging most of the male reproductive system. It is relatively quick, relatively inexpensive, can be correlated quickly with the patient's signs and symptoms, and, most importantly, does not employ ionising radiation.
MRI is occasion...
Testicular and epididymal appendages are remnants of embryonic ducts and are quite common, with one or more being present in ~70% of patients 1.
Four such appendages have been described:
testicular appendix (hydatid of Morgagni)
it is a Müllerian duct remnant (paramesonephric d...
A testicular appendix (alternatively called appendix of testis or appendix testis) represents a developmental remnant of the paramesonephric duct (Müllerian duct) which is situated in the upper pole of the testis inside a groove between the testicle and the head of epididymis 1.
The testicular arteries (also known as the spermatic arteries) are the long, small-diameter gonadal arteries in the male that supply the testis alongside the cremasteric artery and the artery to the ductus deferens.
As paired structures they arise symmetrically, slightly...
Testicular cancers are the most common neoplasm in men between the ages of 20 and 34.
Testicular cancer is uncommon, accounting for less than 1% of all internal organ malignancies 2.
The demographics of affected individuals depends on the age of the histology of the tumour. Over ...
The staging for testicular tumours is performed according to the TNM system with staging groupings. It can be remembered in its abbreviated form as:
stage I: confined to testis, epididymis, spermatic cord, scrotum
stage II: lymph nodes involved but no distant metastases and serum tumour marke...
Testicular choriocarcinoma is a type of non-seminomatous germ cell tumour.
Incidence peaks at around 20-30 years of age.
Can be variable with some patients initially presenting with metastates.
It is most commonly detected as a component of a m...
Simple testicular cysts are usually nonpalpable and thus are detected incidentally.
Testicular cysts require no treatment when discovered.
anechoic with posterior acoustic enhancement
no flow on colour Doppler
Testicular descent occurs after the fourth month of fetal life. The testes are derived from the gonadal ridge medial to the mesonephric ridge of the intermediate cell mass. An elongated diverticulum of the peritoneal cavity, the processus vaginalis precedes the testis through the inguinal canal ...
Testicular dislocation is a rare condition in which a testicle is dislocated from its normal position within the scrotum to another location, most commonly the superficial inguinal pouch.
The condition mainly occurs in younger men with a mean age of 25 years 2.
Testicular embryonal cell carcinoma is a type of non-seminomatous germ cell tumour.
Incidence peaks at around 25-30 years.
It may occur as part of a mixed germ cell tumour (more common and may be present as a component in around 80% of mixed germ cell tumours) or very...
Testicular epidermoid cysts, also known as keratocysts, are rare benign tumours of germ cell origin that occur in the testis.
Testicular epidermoid cysts account for around 1-2% of all testicular masses and typically present in mid-adulthood (2nd to 4th decades) 1,2. They are the...
Testicular fracture refers to a break in the parenchyma of the testicle as a result of blunt trauma.
A fracture line can be seen as a hypoechoic and avascular area within the testis but is only seen in 17% of cases 1. A tunica albuginea rupture may also be pr...
Testicular germ cell tumours account for 90% of primary tumours of the testes. They are the most common nonhaematologic malignancy in men 15-49 years old.
They are divided into:
testicular seminoma: 40% of germ cell tumours 1
non-seminomatous germ cell tumour: 60% of germ cell tumours
Testicular leukaemia can be seen in patients during and after acute leukaemia. The blood-testis barrier limits chemotherapy from reaching the testicle, and therefore the testicle can act as a harbor for leukaemic cells.
Typically presents with painless testicular enlargem...
Testicular lipomatosis is a rare condition characterised by homogeneously hyperechoic non-shadowing lesions within the testes on ultrasound without flow on colour Doppler. It is seen as a component of PTEN (phosphatase and tensin homolog (gene)) hamartoma tumour syndrome which includes:
Testicular lymphoma is an uncommon testicular malignancy. Lymphoma can involve the testes in three ways:
primary site of extranodal disease (primary testicular lymphoma)
secondary involvement of systemic disease
primary manifestation of subclinical systemic disease
This article is concerned ...
Testicular microlithiasis (TM) is a relatively common condition that represents the deposition of multiple tiny calcifications throughout both testes.
The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In t...
Testicular mixed germ cell tumours are, as the name suggests, testicular tumours composed of two or more types of germ cell tumour. They are considered to be part of non-seminomatous germ cell tumours, as it is that component which dictates prognosis and treatment.
Overall they account for ove...
Testicular sarcoidosis is a rare manifestation of sarcoidosis. In cases of urogenital sarcoidosis, more commonly the epididymis is affected.
Testicular sarcoidosis is more common in African-American patients, as are other forms of sarcoidosis 1. Up to 5% of patients with chronic s...
Testicular seminomas are the most common testicular tumours and account for ~45% of all primary testicular tumours. This article concerns itself only with testicular seminomas, however, seminomas can arise outside of the testicle most often within the anterior mediastinum, e.g. anterior mediasti...
Testicular teratoma, unlike ovarian teratoma, is often aggressive in its biological behaviour, and often exists as part of testicular mixed germ cell tumours.
Pure testicular teratomas account for only 4-9% of all testicular tumours. A similar number are seen in the context of t...
Testicular torsion occurs when a testicle torts on the spermatic cord resulting in the cutting off of blood supply. The most common symptom is acute testicular pain and the most common underlying cause, a bell-clapper deformity. The diagnosis is often made clinically but if it is in doubt, an ul...
Testicular trauma is the third most-common cause of acute scrotal pain and may result in various degree of damage to the testes.
Testicular rupture and testicular ischaemia/infarct are two severe complications which need to be ruled out. Other injuries that can occur include 1:
Testicular vasculitis can occur as either part of a systemic vasculitis or an isolated vasculitis involving only the testes with both having roughly equal prevalence.
The mean age of onset is approximately 40 years.
Symptoms can include a testicular mass w...
Testicular yolk sac tumours (also known as endodermal sinus tumour of the testis) is the most common childhood testicular tumour (80%), with most cases occurring before the age of two years 1. In adults, pure yolk sac tumour is extremely rare, however mixed germ cell tumour are commonly seen.
The testes, also known as the testicles, are the male gonads and are contained within the scrotum. The testes are responsible for the production of sperm and testosterone.
At birth, testes measure approximately 1.5 cm (length) x 1 cm (width), reaching ~4 mL volume at puberty 1.
Tethered spinal cord syndrome, also known as an occult spinal dysraphism sequence, is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column.
The condition is closely linked to spina bifida, and as such pre...
Tetralogy of Fallot (TOF) is the overall most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterised by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overridi...
A mnemonic for the underlying anatomic defects in tetralogy of Fallot is:
P: pulmonary stenosis
R: right ventricular hypertrophy
O: overriding aorta
V: ventricular septal defect
The thalamencephalon is an anatomic region that includes the thalamus, metathalamus and epithalamus. It is one of the components that form the diencephalon.
Thalamic haemorrhages or thalamic haemorrhagic strokes are often the result of chronic hypertension. The thalamus transmits or prevents transmission of sensory signals from sensory areas of the cerebral cortex through internal capsule fibres and has a role in memory thus the clinical presentatio...
Thalamostriate veins are formed by the joining of anterior caudate vein and the vein of stria terminalis. They join the septal veins and form internal cerebral veins.
The thalamostriate veins can be compressed in preterm neonates who have had germinal matrix haemorrhage. This...
The thalamus is the largest of the structures comprising the diencephalon.
The thalamus acts as a relay centre, receiving and distributing information between the peripheries and higher centres such as the cerebral cortices. It contributes to functions such as:
Thalassaemia is an autosomal recessive haemoglobinopathy that originated in the Mediterranean region. The genetic defect causes a reduction in the rate of globin chain synthesis which causes the formation of abnormal haemoglobin molecules. The resultant microcytic anaemia is the characteristic p...
Thalidomide embryopathy refers to a syndrome resulting from in utero exposure to thalidomide, and is characterized by multiple fetal anomalies. Fetal exposure to thalidomide occurred primarily from 1957 to 1961, when it was used as a treatment for nausea in pregnant women.
Thallium-201 chloride is a radiopharmaceutical used primarily in cardiac imaging.
photon energy: 80 keV
physical half life: 73 hours
biological half life
rest: 3 minutes
exercise: 30 seconds
normal distribution: myocardium, skeletal muscle, GI tract, liver, kidneys
Thanatophoric dysplasia (TD) is a lethal skeletal dysplasia. It is the most common lethal skeletal dysplasia followed by osteogenesis imperfecta type II.
The estimated incidence is around 1:25,000-50,000 3.
It results from a mutation coding for the fibroblas...
The air gap technique is a radiographic technique that improves image contrast resolution through reducing the amount of scattered radiation that reaches the image detector. In select situations, this technique can be used instead of an anti-scatter grid as the primary scatter reduction method i...
Theca lutein cysts (TLC), also known as hyperreactio luteinalis (HL), are a type of functional ovarian cysts. They are typically multiple and seen bilaterally.
They are thought to originate due to excessive amounts of circulating gonadotrophins such as beta-hCG. Hyperplasia of the th...
The four "Ds" of radiology reporting are the basic sequential tasks that a radiologist performs when reporting/reading a case, whether it be in training, the exam environment or in day-to-day clinical practice.
The 4 "Ds"
Diagnosis or differential diagnoses
In January 2012, we started sharing themed case collections with our facebook and twitter followers. These are a series of selected cases set on a particular subject which we think would be useful for residents, registrars to be familiar with. Below is a list of the case collections posted thus ...
The thenar eminence is the muscular bulge on the radial side of the palm due to the thenar muscles. Together the muscle group primarily acts to oppose the thumb. The four muscles are:
flexor pollicis brevis
abductor pollicis brevis
The thermal index (TI) is intended as a measure of an ultrasound beam's thermal bioeffects. It is often displayed on ultrasound screens (along with the mechanical index).
Absorption of sound waves may cause heating in tissue. The thermal index depends on:
a measure of time-averaged acoustic po...
Thermionic emission is the emission of electrons from a heated metal (cathode). This principle was first used in the Coolidge's tube and then later in the modern day X-ray tubes. Before the discovery of the principle, gas tubes were used for X-ray production.
The cathode has its filament circui...
Thermoluminescent dosimeter (TLD) is a passive radiation detection device that is used for personal dose monitoring or to measure patient dose.
nickel-coated aluminium card with TLD discs
the discs are made of a thermoluminescent material, commonly calcium sulphate dope...
Thickening of bronchovascular bundles is a chest CT imaging feature that can be observed in a number of entities.
Conditions that can result in bronchovascular bundle thickening include:
sarcoidosis - see pulmonary manifestations of sarcoidosis 1
classical condition to giv...
Thiemann disease (also called familial osteoarthropathy of the fingers or osteonecrosis of the base of phalanx) is a non-inflammatory disorder of unknown aetiology and refers to osteonecrosis of the epiphyses of phalanges which leads to deformity of fingers.
Thiemann disease is a ...
Thigh refers to the portion of the lower limb between the hip and knee joints. Note that in an anatomical context "leg" refers to the portion between the knee and ankle joints and not to the entire lower limb.
Thimble bladder is a descriptive term for extreme fibrosis and contracture of the bladder walls, resulting in a tiny bladder. The term is usually used to describe changes from advanced genitourinary tuberculosis.
Third branchial cleft cysts are a very rare type of branchial cleft cysts. Although they are extremely rare, they remain the second most common congenital lesion of the posterior cervical region after cervical lymphatic malformations or cystic hygromas 3.
By definition, a t...
The third condyle (also known as condylus tertius or median occipital condyle) is a rare anatomic variant of the occipital condyles. It is a small separate ossicle at the anteromedial margin of the occipital condyle formed by the failure of the embryonic proatlas (4th occipital sclerotome) to un...
The third mogul sign can be seen on frontal chest radiograph in the presence of left atrial enlargement. It refers to an extra mogul or bump along the upper left cardiac silhouette just below the left main bronchus.
The third mogul sign commonly represents the enlarged left atrial appendage, pa...
The third ventricle is one of the four CSF-filled cavities that together comprise the ventricular system.
The third ventricle is a median cleft between the two thalami and is bounded laterally by them and the hypothalamus. Its anterior wall is formed by the lamina terminalis, and...
A third ventriculostomy is a type of surgical treatment for obstructive hydrocephalus, especially when obstruction is located at the level of the aqueduct of Sylvius (e.g. aqueduct stenosis). A permanent defect is created in the floor of the third ventricle anterior to the mammillary bodies, thu...
Thomas Edison (1847-1931) was a prolific inventor, considered by many to be the greatest inventor in American history. Edison holds around 1093 US patents; however, this article will focus on his work on fluoroscopy.
Early Life and career
Thomas Alva Edison was born on the 11th February 1897 ...
Thoracentesis, commonly known as a pleural tap or chest tap, is a procedure where excess pleural fluid is drained from the pleural space for diagnostic and/or therapeutic reasons. Ultrasound-guided thoracentesis performed by radiologists has been shown to have fewer complications than blind thor...
Thoracic actinomycosis refers to an uncommon indolent infection caused principally by the genus Actinomyces (higher prokaryotic bacteria belonging to the family Actinomyceataceae).
While it is rare in general, the thoracic form actinomycosis constitutes ∼15% of the total burden of...
Thoracic air leak syndrome (TALS) is an uncommon late complication in haematopoetic stem cell transplant recipients with chronic graft verses host disease. These patient led to develop features of thoracic air-leakage (i.e. spontaneous pneumomediastinum, spontaneous pneumothorax, pneumopericardi...
Thoracic anatomy encompasses the anatomy of all structures of the thoracic cavity.
This anatomy section promotes the use of the Terminologia Anatomica, the global standard for correct gross anatomical nomenclature.
The thoracic aorta is the most superior division of the aorta and is divided into three sections:
The thoracic aorta begins at the aortic valve, located obliquely just to the left of the midline at the level of the the third intercostal space. It ...
Thoracic aortic aneurysms are relatively uncommon compared to abdominal aortic aneurysms. There is a wide range of causes, and the ascending aorta is most commonly affected. CTA and MRA are the modalities of choice to image this condition.
The normal aortic diameter varies based on...
There are a number of causes and mimics of thoracic aortic dilatation.
post-stenotic dilatation, e.g. bicuspid aortic valve
thoracic aortic aneurysm
atherosclerosis (usually descending thoracic aorta)
Thoracic aortic injury is the most common type of traumatic aortic injury and is a critical life-threatening, and often life ending event.
Approximately 80% of patients with thoracic aortic injury die at the scene of the trauma. In those who make it to hospital, clinical...
The differential for thoracic aortic stenosis includes:
aortitis (especially Takayasu arteritis)
Williams syndrome: supravalvular aortic stenosis
congenital rubella syndrome: supravalvular aortic stenosis
The thoracic cage refers to the skeleton of the thorax:
thoracic vertebral column
12 pairs of ribs
The thoracic duct is the main lymphatic channel for the return of chyle to the venous system. It drains lymph from both lower limbs, abdomen (except the convex area of the liver), left hemithorax, left upper limb and left face and neck.
The thoracic duct is the superior continua...
Pleural-thoracic empyema (commonly referred simply as an empyema) or pyothorax refers to an infected purulent and often loculated pleural effusion, and is a cause of a large unilateral pleural collection. It is a potentially life-threatening condition requiring prompt diagnosis and treatment.
Thoracic endometriosis is an uncommon location for endometriosis and the main cause of catamenial pneumothorax.
Most often occurs in the third and fourth decades of life 3.
Symptoms may include:
catamenial pleuritic chest pain
catamenial haemoptysis: whe...
Thoracic (or pulmonary) histoplasmosis refers to pulmonary manifestations from infection with the organism Histoplasma capsulatum which is an organism endemic to El Salvador but can be found widely in other parts of North, Central and South America. It can have variable clinical and radiographic...
High resolution CT (HRCT) of the lungs has specific terminology relating to pulmonary anatomy with which one needs to be comfortable.
secondary pulmonary lobule
interlobular septal thickening
Thoracic lymph nodes are divided into 14 stations as defined by the International Association for the Study of Lung Cancer (IASLC) 1, principally in the context of oncologic staging. For the purpose of prognostication, the stations may be grouped into 7 zones.
Station 1 (l...
Thoracic myelolipomas are extremely rare entities; only ~3% of myelolipomas are thought to occur in the thorax. When do occur in the thorax they can manifest as
mediastinal myelolipoma: most occur in the posterior mediastinum
intrapulmonary myelolipoma (much less common)
As with my...