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.

438 results found
Article

Intervertebral disc calcification

Intervertebral disc calcification is seen with numerous conditions. degenerative: relatively common and may occur in up to 6% in routine abdominal radiographs in adults postoperative/traumatic ochronosis: very dense central (nucleus pulposus) calcification associated with osteopaenia; begins ...
Article

Intervertebral disc vacuum phenomena

Vacuum phenomena involving the intervertebral discs are a result of accumulation of gas (principally nitrogen) within the crevices of the intervertebral discs or adjacent vertebrae. Epidemiology It is a common occurrence which can be observed in 1-3% of spinal radiographs and may even reach a ...
Article

Intervertebral foramen

The intervertebral foramina allow passage of structures out of and into the vertebral canal.   Boundaries Anterior- lower posterolateral aspect of a vertebral body and the intervertebral disc below in the cervical region a portion of the vertebral body below, predominately the uncinate proce...
Article

Intervertebral joint

There are three intervertebral joints between each adjacent vertebra from the axis to the sacrum – one between the vertebral bodies and a pair between the facets of adjoining vertebral arches (zygapophysial joints, also called facet joints). Gross anatomy Movement flexion: the anterior interv...
Article

Intervertebral osteochondrosis

Intervertebral osteochondrosis represents the pathologic degenerative process involving the intervertebral disc and the respective vertebral body endplates (not necessarily symptomatic). It is believed to be different and a further stage of spondylosis deformans, which is a consequence of normal...
Article

Intradural disc herniation

Intradural disc herniations (IDH) occur when disc material related to an intervertebral disc hernia penetrate the spinal dura and lies in an intradural extramedullary location. Epidemiology IDH correspond to a rare presentation of a common pathology, comprising ~0.28% of all disc herniations 2...
Article

Intradural extramedullary metastases

Intradural extramedullary metastases are rare and only account for approximately 5% of spinal metastases. Please refer on leptomeningeal metastases (brain) to a general discussion focused on the brain's subarachnoid space involvement. Epidemiology The age at presentation depends on tumour typ...
Article

Intradural extramedullary spinal tumours

Intradural extramedullary neoplasms are located outside the spinal cord but within the dural sheath.  Clinical presentation The most common presenting symptoms include weakness, back pain and radicular pain. Pathology Schwannomas are the most common intradural extramedullary spinal lesions (...
Article

Intradural spinal lipoma

Intradural lipomas are a subset of spinal lipomas. They are typically intradural, subpial, juxtamedullary lesions 1 although they have occasionally been reported as entirely intramedullary lesions 2. Mature fatty tissue within the spinal dura can be seen in a number of entities: lipomyelomenin...
Article

Intradural spinal mass lesions (an approach)

Intradural spinal mass lesions are relatively uncommon, compared to intracranial or extradural masses, and can be challenging to diagnose. Additionally, the need for a pre-operative/non-operative diagnosis is in many ways greater as biopsy of lesions within the cord has the potential of devastat...
Article

Intramedullary spinal metastasis

Intramedullary spinal metastases are rare, occurring in ~1% of autopsied cancer patients, and are less common than leptomeningeal metastases. Intramedullary lesions may result from: growth along the Virchow-Robin spaces haematogenous dissemination direct extension from leptomeninges Epidemi...
Article

Intramedullary spinal tumours

Intramedullary spinal tumours are rare, representing 4-10% of all CNS tumours and less than 10% of all paediatric CNS neoplasms 5. They account for 20% of all intraspinal tumours in adults and 35% of all intraspinal tumours in children 8. A long duration of symptoms prior to diagnosis is typica...
Article

Inverted Napoleon hat sign

The inverted Napoleon hat sign is a radiologic sign seen on the frontal pelvic or lumbar radiograph at the level of the 5th lumbar vertebra and the sacrum. It is seen when there is bilateral spondylolysis with marked anterolisthesis of L5 on S1 or marked exaggeration of the normal lordosis at t...
Article

Iodophenylundecylic acid

Iodophenylundecylic acid (brand name = Myodil (Glaxo)) is an oily organic iodinated contrast material which was used for myelography. It is no longer used. Residual contrast remains for years. Has been implicated in development of arachnoiditis, perhapse of the order of 1%. See also pantopaque
Article

Ivory vertebra sign

The ivory vertebra sign refers to diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours, and with no change in the opacity and size of adjacent intervertebral discs. Pathology Aetiology The cause for an ivory vertebra depends on the age o...
Article

Jefferson fracture

Jefferson fracture is the eponymous name given to a burst fracture of C1. It was originally described as a four-part fracture with double fractures through the anterior and posterior arches, but three-part and two-part fractures have also been described. Pathology Mechanism A typical mechanis...
Article

Klippel-Feil syndrome

Klippel-Feil syndrome (KFS) is a complex heterogeneous entity that results in cervical vertebral fusion. Two or more non-segmented cervical vertebrae are usually sufficient for diagnosis. Epidemiology There is a recognised female predilection 1. KFS has an incidence of 1:40,000-42,000 2. Clin...
Article

Kümmell disease

Kümmell disease is an eponymous name for avascular necrosis and collapse of a vertebral body. Pathology Kümmell disease represents delayed (usually two weeks) vertebral body collapse due to ischaemia and non-union of the anterior vertebral body wedge fractures after major trauma. Risk factors...
Article

Laminectomy

Laminectomy refers to unilateral or bilateral surgical removal of the lamina of a vertebra body. It is performed to decompress the spinal canal in spinal canal stenosis.  This is typically caused by degenerative changes. The most common site of the procedure is the lumbar spine. 
Article

Lateral corticospinal tract

The lateral corticospinal tract is formed at the level of the of the medullary pyramids when the majority (90%) of descending corticospinal tract fibres decussate – the majority of the remaining non-decussating 10% of fibres form the much smaller anterior corticospinal tract, with only a few non...
Article

Lateral hemivertebra

A lateral hemivertebra is a form of hemivertebra which occurs when one of the two chondrification centre fails to develop. They can be single or multiple. and a usually associated this a resultant scoliosis.  Pathology Subtypes Various subtypes have been descrbied incarcerated hemivertebra ...
Article

Lateral meningocele syndrome

The lateral meningocele syndrome is an extremely rare hereditary connective tissue disorder characterized by multiple lateral lumbar meningoceles, distinctive facial features, joint hypermobility, hypotonia, skeletal abnormalities, congenital cardiovascular malformations, urogenital anomalies an...
Article

Lateral spinothalamic tract

The lateral spinothalamic tract, also known as the lateral spinothalamic fasciculus, is an ascending pathway located anterolaterally within the peripheral white matter of the spinal cord. It is primarily responsible for transmitting pain and temperature as well as coarse touch.  The anterior sp...
Article

Lateral thoracic meningocele

Lateral thoracic meningoceles are a type of spinal meningocoele. Pathology As with any meningocele, it results from herniation of the meninges through a foramen or a defect in the vertebral column.  Associations They are typically associated with neurofibromatosis type I but can rarely occur...
Article

Leptomeningeal drop-metastases

Leptomeningeal drop-metastases correspond to a CNS primary neoplasm spread inferiorly along the cerebrospinal spaces. It is usually presented as diffuse enhancing nodules along the spine and cauda equina.  Please refer on leptomeningeal metastases to a broad discussion on this entity. 
Article

Leptomeningeal metastases

Leptomeningeal metastases, also know as carcinomatous meningitis, refers to the spread of malignant cells through the CSF space. These cells can be originated both in primary CNS tumours (e.g. drop-metastases), as well as from distant tumours that have metastasised (haematogenous spread). This ...
Article

Levine and Edwards classification

Levine and Edwards classification is used to classify hangman fractures of C2 (also known as traumatic spondylolithesis of axis). Classification type I: fracture with <3 mm antero-posterior deviation no angular deviation type II: fracture with >3 mm antero-posterior deviation significant an...
Article

Ligamentum flavum

The ligamentum flavum is a paired ligament which runs between adjacent laminae of the vertebral bodies. It forms part of the posterior ligamentous complex of the vertebral column. Gross anatomy paired, yellowish, elastic ligament forms part of the posterior border of the spinal canal relativ...
Article

Ligamentum nuchae

The ligamentum nuchae is a large median ligament composed of tendons and fascia located between the posterior muscles of the neck. It covers the spines of C1 to C6 vertebrae. It is a superior and posterior extension of the supraspinous ligament. It rises from the spinous process of C7 to the ini...
Article

Limbus vertebra

Limbus vertebra is a well-corticated osseous density, usually of the anterosuperior vertebral body corner, that occurs secondary to herniation of the nucleus pulposus through the the vertebral body endplate beneath the ring apophysis (see ossification of the vertebrae). These are closely related...
Article

Lipoma of the filum terminale

Fatty filum terminale, also known as lipoma of the filum terminale or filar lipoma, is a relatively common finding on imaging of the lumbar spine, and in most cases is an incidental finding of no clinical concern. However, in some patients it may be associated with signs and symptoms of tethered...
Article

Lipomyelocele

Lipomyelocele is one of the most common closed spinal dysraphism. It is seen in thoracolumbar region and usually presents as a fatty subcutaneous mass. It is twice as common as lipomyelomeningocele. Clinical presentation Affected individuals are usually asymptomatic at birth, but many (~ 50%)...
Article

Locked facet joint

Locked facet joint is a type of facet joint dislocation that results from jumping of the inferior articular process over the superior articular process of the vertebra below and becomes locked in the position. It can be unilateral or bilateral. Radiographic features Plain radiograph The tip ...
Article

Longitudinally extensive spinal cord lesion

Longitudinally extensive spinal cord lesions (LESCL), also known as longitudinally extensive transverse myelitis (LETM), represent extensive involvement of the spinal cord, with abnormal T2 signal traversing at least three vertebral body segments in length. Differential diagnosis They are typi...
Article

Loss of intervertebral disc space (differential)

Loss of intervertebral disc space can be due to a variety of causes: degenerative disc disease of the spine: most common cause trauma discitis neuropathic spondyloarthropathy dialysis related spondyloarthropathy ankylosing spondylitis ochronosis crystal deposition diseases sarcoidosis ...
Article

Low endplate signal on T1

Several conditions may give vertebral endplate T1 low signal on MRI. They include:   ankylosing spondylitis vertebral metastases disc infection haemodialysis
Article

Lumbar cistern

The lumbar cistern refers to the subarachnoid space in the lower lumbar spinal canal. The cistern is an enlargement of the subarachnoid space in the dural sac, distal to the conus medullar is. It contains cerebrospinal fluid and the nerve roots of the cauda equina. As the conus (usually) termin...
Article

Lumbar disc disease

Lumbar disc disease is a very common entity with a high asymptomatic prevalence. Intervertebral disc abnormalities are found in 25% of individuals below the age of 60, and over 50% in those over the age of 60. It is therefore not enough to demonstrate a disc lesion in someone with non-specific b...
Article

Lumbar enlargement

The lumbar enlargement of the spinal cord corresponds to the mild increase in cross sectional area of the cord from the T11 level to the conus medullaris. It is enlarged due to the present of spinal nerve anterior rami which contribute to the lumbar and sacral plexuses.
Article

Lumbar interlaminar epidural injection

Lumbar interlaminar epidural injections are one of some possible spinal epidural injections. For an alternative approach for the same region, please refer to the article on lumbar transforaminal epidural injections.  Indications Typically, epidural injections are performed in patients with rad...
Article

Lumbar plexus

The lumbar plexus is a complex neural network formed by the lower thoracic and lumbar ventral nerve roots (T12 to L5) which supplies motor and sensory innervation to the lower limb and pelvic girdle. Summary origin: ventral rami of T12 to L5 course: formed within the substance of the psoas ma...
Article

Lumbar plexus roots (mnemonic)

A handy mnemonic to recall the roots of the lumbar plexus is: 2 from 1, 2 from 2, 2 from 3 Mnemonic 2 nerves from 1 root: ilioinguinal (L1), iliohypogastric (L1) 2 nerves from 2 roots: genitofemoral (L1/L2), lateral femoral cutaneous (L2/L3) 2 nerves from 3 roots: obturator (L2/L3/L4), femo...
Article

Lumbar rib

Lumbar (or 13th) ribs are a rare anatomical variant and represent transitional vertebrae at the thoracolumbar junction with a prevalence of ~1% 1. It presents as an additional rib coming off T13 or L1 (depending on numbering classification) and may be unilateral or bilateral. Lumbar ribs are mos...
Article

Lumbar spine

The lumbar spine consists of five adjacent vertebrae of the mid-lower vertebral column. They participate in the lumbar lordosis, a natural curve in the spine, that is convex anteriorly.  Articulations of the facet (zygapophyseal) joints permit flexion/extension and abduction movements. Rotation...
Article

Lumbar spine (AP/PA view)

The lumbar spine AP view images the lumbar spine which consists of five vertebrae. It is utilised in many imaging contexts including trauma, postoperatively, and for chronic conditions.  Patient position the patient is erect or supine, depending on clinical history ideally, spinal imaging sho...
Article

Lumbosacral transitional vertebra

Lumbosacral transitional vertebrae (LSTV) are a relatively common variant and can be seen in ~25% (range 15-35%) of the general population 1-3. Non-recognition of this variant and/or poor description in the report can lead to operations or procedures performed at the wrong level.  Depending on ...
Article

Lymphoma of the spinal cord

Lymphoma of the spinal cord is an uncommon manifestation of lymphoma. Although lymphoma more commonly involves the vertebral body (vertebral body tumours) or epidural compartment, intramedullary lymphoma may rarely occur.   Apparent intramedullary spinal cord lymphoma may often, in fact, repres...
Article

Magerl classification of thoracolumbar spinal fractures

The Magerl classification of thoracolumbar spinal fractures is based on the three column concept by Denis, and the McAfee classification. It relies exclusively on CT findings. Classification A: compression injuries A1: impaction fractures A1.1: endplate impaction A1.2: wedge impaction A1.3...
Article

Matterhorn sign

The Matterhorn sign is a descriptive sign for a calcified disc herniation that impales the dural sac and sometimes the cord, typically located in the thoracic spine. History and etymology The Matterhorn sign is named after one of the most iconic mountains in the Alps: the Matterhorn.
Article

McRae line

McRae line is a radiographic line drawn on a lateral skull radiograph or midsagittal section of CT or MRI, joining the basion and opisthion. Normal position of the tip of dens is 5mm below this line. If the tip of the dens migrates above this line it indicates the presence of basilar invaginati...
Article

Meningeal melanocytoma

Meningeal melanocytomas are rare benign primary melanocytic tumours of the CNS that are derived from leptomeningeal melanocytes. They can occur anywhere along the neuraxis but are most commonly found in the spinal canal near the foramen magnum, as well as the posterior fossa, Meckel’s cave, or a...
Article

Meningocele

Meningoceles are protrusions of the meninges through a defect or weak point in the skull or spine, usually involving the soft tissues beneath the surface of the skin. They are typically categorized into congenital, iatrogenic (e.g. following a craniotomy, sinus surgery, or as a laminectomy compl...
Article

Meningocele manqué

Meningocele manqué (from French, literally "missed meningocele") is a rare condition characterized by focal dorsal tethering of the spinal cord. The term is used to designate a meningocele which failed to develop and became atretic. Epidemiology It has been reported in neonates, but median age...
Article

Modic type endplate changes

Modic type endplate changes represent a classification for vertebral body end-plate MRI signal, first described in 1988 1. It is widely recognised by radiologists and clinicians and is a useful shorthand for reporting MRIs of the spine. Recently Modic type I has received renewed attention due t...
Article

Modic type I endplate change

Modic type I endplate change is the most controversial and important of the three types described (see Modic endplate change).  It is seen on MRI of the spine and represents the presence of low T1 and high T2 signal within the bone marrow of a vertebral body adjacent to a disk. Type 1 change can...
Article

Modified Memphis criteria for blunt cerebrovascular injury

The modified Memphis criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) in trauma. The presence of one or more of these criteria makes necessary a complementary CTA or DSA study to exclude a BCVI. The screening protocol criteria for BCVI are: base of skull fractur...
Article

MRI classification system for lumbar disc degeneration

Disc degeneration can be graded on MRI T2 spin-echo weighted images using a grading system proposed by Pfirrmann 1. This classification is not used on routine spine reports, being more important for research purposes. grade I: disc is homogeneous with bright hyperintense white signal intensity ...
Article

Musculoskeletal hydatid infection

Musculoskeletal hydatid infections are a very rare form of Echinococcosis/hydatidosis. For a general discussion see hydatid disease. Clinical presentation Patients usually present with slow growing swelling with or without pain. Location They can present almost anywhere, but most common loc...
Article

Myelitis

Myelitis, is a collective term simply referring to any inflammation of the spinal cord. It is a form of myelopathy. The two major sub types include: leukomyelitis multiple sclerosis ADEM transverse myelitis ideopathic transverse myelitis secondary transverse myelitis: viral, syphillis 2, ...
Article

Myelomeningocoele

Myelomeningocoele, also known as spina bifida cystica, is a complex congenital spinal anomaly that results in spinal cord malformation (myelodysplasia).  Epidemiology It is one of the commonest congenital CNS anomalies and thought to occur in approximately 1:500 of live births 5. There may be ...
Article

Naked facet sign (vertebral column)

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...
Article

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...
Article

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 ...
Article

Neurenteric canal of Kovalevsky

The neurenteric canal or canal of Kovalevsky is the transient communication of the amnion through notochordal canal to the yolk sac during notochordal formation at day 16-17. Abnormalities during this stage produce the neurenteric cyst spectrum.
Article

Neurenteric cyst

Neurenteric cysts are a rare type of foregut duplication cyst, accounting for ~1% of all spinal cord tumours. They are usually classified as spinal or intracranial, and are associated with vertebral or CNS abnormalities respectively.  Pathology Neurenteric cysts result from incomplete resorpti...
Article

Neurogenic bladder

Neurogenic bladder is a term applied to a dysfunctional urinary bladder that results from an injury to the central or peripheral nerves that control and regulate urination. Injury to the brain, brainstem, spinal cord or peripheral nerves from various causes including infection, trauma, malignanc...
Article

Normal spine imaging examples

This page lists examples of normal imaging of the spine, divided by region and modality. Cervical spine plain films example 1: AP, lat, obliques only example 2: PEG view example 3: flexion and extension views only example 4: paediatric - 12 years old example 5: including Swimmer's view C...
Article

Nucleus pulposus

The nucleus pulposus is the central part of each intervertebral disc. Gross anatomy It is located within the annulus fibrosus and between the vertebral body endplates. It is composed of a thin lattice of collagen fibres (type II) which traverse though hydrophilic glycosaminoglycans.  With age...
Article

Nude nerve root

A nude nerve root is perhaps not as exciting as the name would suggest. It refers to an uncommon anatomical variant where nerve roots simply exit the theca without investing dural sleeves 1. These have been associated, at least in case reports, with spontaneous craniospinal hypotension 1. 
Article

Occipital condyle fracture

Occipital condylar fractures result from high-energy blunt trauma. Epidemiology The exact incidence of these fractures is unknown but are reported to occur in 3-4% patients with moderate-severe traumatic brain injuries 3. Clinical presentation History and examination are unreliable, and high...
Article

Occipital vertebrae

Occipital vertebrae is a very rare anatomical variant and results from incomplete or aberrant fusion of occipital bone ossification centres. There is a broad spectrum of occipital vertebrae variations and the four most common include: third condyle (condylus tertius) basilar process paracondy...
Article

Occult intrasacral meningocoele

Occult intrasacral meningocoele is a rare congenital lesion characterised by the presence of a cyst within the sacral thecal sac. It is an extradural sacral arachnoid cyst, not a true meningocoele, since meninges are not involved. It is associated with spinal dysraphism, tethered cord syndrome ...
Article

Ochronosis

Ochronosis, or alkaptonuria, is a rare multisystem autosomal recessive metabolic disorder. On imaging, the most particular presentation is on the spine, with osteoporotic bones and dense disc calcifications.  Terminology The term ochronosis usually refers to the bluish black discoloration of ...
Article

Odontoid fracture

Odontoid process fracture, also known as the peg or dens fracture, occurs where there is a fracture through the odontoid process of C2. Pathology The mechanism of injury is variable, and can occur both during flexion or extension with or without compression 5. Classification There are two cl...
Article

Olisthesis

Olisthesis, also known as the etymologically less correct listhesis, means slipping or sliding. Types It can be: anterolisthesis spondylolisthesis spondylolisthesis grading retrolisthesis
Article

Oppenheimer ossicle

Oppenheimer ossicles are accessory ossicles associated with the facet joints found in ~4% (range 1-7%) 1 of lumbar spines.  Oppenheimer ossicles are thought to arise as a result of non-union of a secondary ossification centre of the articular process. They predominantly occur as a single, unila...
Article

Opticospinal multiple sclerosis

Opticospinal multiple sclerosis (OSMS) is a demyelinating disease and has been considered a variant of multiple sclerosis (MS) encountered in Asian populations, who are generally rarely affected by normal multiple sclerosis. It has similar clinical and imaging features to neuromyelitis optica (N...
Article

Os odontoideum

Os odontoideum is an anatomic variant of the odontoid process of C2 and needs to be differentiated from persistent ossiculum terminale and from a type 2 odontoid fracture. It can be associated with atlantoaxial instability.  Although it was originally thought to be a congenital lesion due to a ...
Article

Ossification centres of the vertebral column

Ossification of the vertebral column is complex but an overview of primary and secondary ossification centres is given below: Primary ossification centres The C3-L5 vertebrae typically have three primary ossification centres that start appearing at 9 weeks in utero and finish primary ossificat...
Article

Ossification of the ligamentum flavum

Ossification of the ligamentum flavum (OLF) is a phenomenon where there is formation of ossific-calcific components in the ligamentum flavum. It is recognised causes of myelopathy (especially in the thoracic and to a lesser degree the cervical region). Epidemiology The condition as a whole is ...
Article

Ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL) is typically an entity seen in patients of Asian descent, although it is seen in all ethnic groups. It is characterised by, as the name suggests, ossification of the posterior longitudinal ligament. Epidemiology There is a recognised g...
Article

Osteoarthritis of the vertebral column

Osteoarthritis of the vertebral column, also known as spondylosis deformans, is common and usually merely referred to as spinal "degenerative change". Complications such as spinal stenosis are important to recognise.  Radiographic features The hallmark of osteoarthritis in the spine, as is the...
Article

Osteoporotic spinal compression fracture

Osteoporotic spinal compression fractures occur as a result of injury, commonly fall onto the buttock or pressure from normal activities, to the weakened vertebrae due to osteoporosis. Epidemiology They have a reported incidence of 1.2 per 1000 person-years after 85 years of age in the United ...
Article

Owl's eye sign

The owl's eye sign represents bilaterally symmetric circular to ovoid foci of high T2-weighted signals in the anterior horn cells of the spinal cord and is seen on axial MR imaging. The sagittal corollary is a "pencil-like" vertical linear high T2-weighted signal extending usually over a number ...
Article

Pantopaque

Pantopaque is an oily contrast medium that used to be used for myelography. Its generic name is iodophenylundecylic acid and it was first used in 1944.  A major drawback is the lack of resorption. Complete removal through aspiration is usually impossible after a procedure and the remaining drop...
Article

Paracondylar process

Paracondylar process is a rare anatomical variant of the occipital bone, where a bony exostosis extends caudally from the paracondylar region (lateral to the native occipital condyles), typically articulating with the superior surface of a transverse process of the atlas. This may be unilateral ...
Article

Parasyndesmophytes

Parasyndesmophytes or floating syndesmophytes are, as the name suggests, paravertebral dystrophic soft tissue calcifications or heterotopic ossifications. Pathology They are known to be seen in psoriatic arthritis and reactive arthritis 4. Radiographic features Initially they begin at a dist...
Article

Perched facet joint

Perched facet joint is a vertebral facet joint whose inferior articular process appears to sit 'perched' on the ipsilateral superior articular process of the vertebra below. Any further anterior subluxation will result in dislocation, with one facet "jumping" over the other and becoming locked...
Article

Peripheral nerve sheath tumours

Peripheral nerve sheath tumours (PNSTs) are a group of primary neurogenic tumours that arise from nerve sheaths outside of the central nervous system. The vast majority are benign, however, malignant transformation is seen particularly in large tumours and those associated with neurofibromatosis...
Article

Perivertebral space

The perivertebral space is one of the seven deep compartments of the head and neck. Gross anatomy The perivertebral space is a cylinder of soft tissue lying posterior to the retropharyngeal space and danger space surrounded by the prevertebral layer of the deep cervical fascia and extends from...
Article

Persistent ossiculum terminale

The ossiculum terminale appears as a secondary ossification centre of the dens between 3-6 years and normally fuses by 12 years. Failure of fusion results in a persistent ossiculum terminale (also called Bergmann's ossicle or ossiculum terminale of Bergmann) and is considered a normal anatomical...
Article

Picture frame vertebral body

Picture frame vertebral body is a radiologic appearance in which the cortex of the vertebral body is thickened. This sign is seen in a patient with Paget disease.  This is a result of disorganized new cortical bone formation after excessive osteoclastic activity causes the resorption of normal ...
Article

Pine cone bladder

A pine cone bladder or christmas tree bladder is a cystogram appearance in which the bladder is elongated and pointed with thickened trabeculated wall. It is typically seen in severe neurogenic bladder with increased sphincter tone (detrusor sphincter dyssynergia) due to suprasacral lesions (abo...

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.