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.

384 results found
Article

Accessory ossicle of the anterior arch of the atlas

The accessory ossicle of the anterior arch of the atlas is a normal variant and is best appreciated on a lateral cervical/sagittal study. It is observed as a circular and corticated osseous density that articulates with the inferior aspect of the anterior arch of the atlas.  It is not associate...
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Acute spinal cord ischaemia syndrome

Acute spinal cord ischaemia syndrome (ASCIS) is uncommon, but usually presents with profound neurological signs and symptoms, and prognosis is generally poor.  Epidemiology Acute spinal cord ischaemia syndrome represents only 5-8% of acute myelopathies 4,5 and <1% of all strokes 7. The demo...
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Alar ligament

The alar ligaments join the lateral margins of the sloping upper margin of the dens to the margins of the foramen magnum (adjacent to the occipital condyles) and lie on either side of the apical ligament. They are paired ligaments that are very strong and limit rotation of the head.
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Allen and Ferguson classification of subaxial cervical spine injuries

This classification was proposed by Allen and Ferguson in 19823 and at the time of writing (July 2016) remains the most widely used system for describing subaxial cervical spine injury. Allen and Ferguson classification is used for research purposes to classify subaxial spine injuries. It is ba...
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Ancient schwannoma

Ancient schwannomas are long-standing, slow growing schwannomas with advanced degeneration. These can have calcification, hyalinization, and cystic cavitation that can be identified on imaging. The term “ancient” has been traditionally used to describe schwannomas showing degenerative changes an...
Article

Andersson lesion

Andersson lesions refer to inflammatory involvement of the intervertebral discs by spondyloarthritis. Epidemiology Rheumatic spondylodiscitis is a non-infectious condition that has been shown to occur in about 8% of patients with ankylosing spondylitis, as detected at radiography. Pathology ...
Article

Angiolipoma

Angiolipomas (also sometimes known as haemangiolipomas, vascular lipomas, and fibromyolipomas) are rare soft tissue tumours composed of mature adipocytes and vessels. They can occur essentially anywhere, and can be subclassified into infiltrating and non-infiltrating varieties 1.  The most comm...
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Ankylosing spondylitis

Ankylosing spondylitis (less commonly known as Bechterew disease and Marie Strümpell disease) is a seronegative spondyloarthropathy, which as the name suggests, results in fusion (ankylosis) of the spine and sacroiliac (SI) joints, although involvement is also seen in large and small joints.  E...
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Annular fissure

Annular fissures are a degenerative deficiency of one or more layers that make up the annulus fibrosus of the intervertebral disc.  Terminology Many authors prefer the term annular fissure over annular tear, as the latter seems to imply acute injury 1,2. In the setting of severe trauma with di...
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Annulus fibrosus

The annulus fibrosus surrounds the nucleus polposus and together they form the intervertebral disc. Gross anatomy The annulus comprises 15 to 20 collagenous (type I) laminae which run obliquely from the edge of one vertebra down to the edge of the vertebra below. The direction of the fibres al...
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Anterior angulation of the coccyx

Anterior angulation of the coccyx may be a normal variant but poses a diagnostic challenge for those considering coccygeal trauma. Classification Four types of coccyx have been described type I: the coccyx is curved slightly forward, with its apex pointing caudally (~70%) type II: the coccyx...
Article

Anterior atlanto-occipital membrane

The anterior atlanto-occipital membrane joins the upper border of the anterior arch of the atlas to the outer margin of the foramen magnum.
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Anterior cord syndrome

Anterior cord syndrome (also known as Beck's syndrome or anterior spinal artery syndrome) is a clinical subset of spinal cord injury syndromes, due to ischaemia/infarction of the anterior two-thirds of the spinal cord, typically sparing posterior third. Clinical presentation Patient present wi...
Article

Anterior horn syndrome

Anterior horn syndrome is a fairly generic term used to refer to flaccid paralysis and areflexia due to involvement of the anterior grey matter horns of the spinal cord. Sensation is typically preserved.  Causes of anterior horn syndrome include:  anterior spinal artery ischaemia  poliomyelit...
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Anterior longitudinal ligament

The anterior longitudinal ligament (ALL) arises from the anterior tubercle of the atlas, travels downwards, anterior to the vertebral bodies (firmly united to the periosteum) and intervertebral discs (attaching to the anterior annulus), attaching to the front of the upper part of the sacrum. It ...
Article

Anterior sacral meningocele

Anterior sacral meningocele is a congenital defect seen in the anterior aspect of the spine. It is defined as a meningeal cyst that occurs in the presacral space secondary to agenesis of a portion of the anterior sacrum.  Pathology Associations In approximately 50% of cases, associated malfor...
Article

Anterior spinal artery

The anterior spinal artery supplies the anterior portion of the spinal cord and arises from the vertebral artery in the region of the medulla oblongata. The two arteries (one of which is usually bigger than the other) anastamose in the midline to form a single anterior spinal artery at the level...
Article

Anterior subluxation of cervical spine

Anterior subluxation of cervical spine (also known as hyperflexion sprain) is a ligamentous injury to the cervical spine. Clinical presentation Patient presents with neck pain. There may be symptoms due to spinal cord oedema. Pathology It results from ligamentous injury, however, there may b...
Article

Anterior vertebral body beaking

Anterior vertebral body beaking occurs in a number of conditions and may eminate from the central portion or the lower third of the vertebral body. Middle third Morquio syndrome 1 (middle for Morquio) Lower third Hurler syndrome 2 achondroplasia 3 pseudoachondroplasia 4 cretinism 5 Down ...
Article

Anterolisthesis

The term anterolisthesis refers to anterior displacement (forward slip) of vertebral body relative to one below.
Article

Apical ligament

The apical ligament joins the apex of the dens to the anterior margin of the foramen magnum. It is the weak, fibrous remnant of the notochord.
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Arachnoid cyst

Arachnoid cysts are relatively common benign and asymptomatic lesions occurring in association with the central nervous system, both within the intracranial compartment (most common) as well as within the spinal canal. They are usually located within the subarachnoid space and contain CSF.  On ...
Article

Arachnoiditis

Arachnoiditis is a broad term encompassing inflammation of the meninges and subarachnoid space. Terminology Arachnoiditis affecting the cauda equina may be referred to as spinal/lumbar adhesive arachnoiditis.  Clinical presentation Lumbar spine arachnoiditis can result in leg pain, sensory c...
Article

Arcuate foramen

The arcuate foramen (or foramen arcuale atlantis, ponticulus posticus or Kimerle foramen) is a frequently encountered normal variant of the atlas and is easily appreciated on a lateral plain film of the cranio-cervical junction. It develops by calcification of the oblique atlanto-occipital liga...
Article

Artery of Adamkiewicz

The artery of Adamkiewicz, also known as the great anterior radiculomedullary artery or arteria radicularis anterior magna, is the name given to the dominant thoracolumbar segmental artery that supplies the spinal cord. Gross anatomy Origin The artery of Adamkiewicz has a variable origin but ...
Article

Atlanto-axial articulation

The atlanto-axial articulation is a complex of three synovial joints, which join the atlas (C1) to the axis (C2). Gross anatomy Articulations paired lateral atlanto-axial joints: classified as planar-type joint between the lateral masses of C1 and C2, though somewhat more complex in shape wit...
Article

Atlanto-occipital articulation

The atlanto-occipital articulation is comprised of a pair of condyloid synovial joints that connect the occiput (C0) to the first cervical vertebra (atlas/C1). Gross anatomy Articulations Each joint is comprised of two concave articular surfaces on the superior aspect of the lateral mass of a...
Article

Atlanto-occipital assimilation

Atlanto-occipital assimilation is the fusion of the atlas (C1) to the occiput and is one of the transitional vertebrae.  Epidemiology Atlanto-occipital assimilation occurs in ~0.5% (range 0.25-1%) of the population 2-4.  Clinical presentation Atlanto-occipital is typically asymptomatic but s...
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Atlanto-occipital dissociation injuries

Atlanto-occipital dissociation (AOD) injuries are severe and include both atlanto-occipital dislocations and atlanto-occipital subluxations. Pathology The tectorial membrane and alar ligaments provide the most the stability to the atlanto-occipital joint, and injury to these ligaments results ...
Article

Atlantodental interval

The atlantodental interval (ADI), as the name suggests, is the horizontal distance between the anterior arch of the atlas and the dens of the axis, used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis. It is the distance (in mm) between the posteri...
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Atlas (C1)

The atlas is the first cervical vertebra, commonly called C1. It is an atypical cervical vertebra with unique features. It articulates with the dens of the axis and the occiput, respectively allowing rotation of the head, and flexion, extension and lateral flexion of the head.  Unlike the rest o...
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Atypical cervical vertebrae

Of the cervical vertebrae, the atlas (C1), axis (C2) and vertebra prominens (C7) are considered atypical cervical vertibrae. The atlas (C1) lacks a body or spinous process. It has an anterior and posterior arches with lateral masses. Its superior articular surfaces articulate with the occiput a...
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Atypical lumbar vertebrae

Of the five lumbar vertebrae, L5 is considered atypical due to its shape. The remaining lumbar vertebrae are largely typical.
Article

Atypical thoracic vertebrae

T1 and T9 to T12 are considered atypical vertebrae. T1 bears some resemblance to low cervical vertebrae. T9 has no inferior demifacet. T10 often, but not always, shares features with T11 and T12. 
Article

Axis (C2)

The axis is the second cervical vertebra, commonly called C2. It is an atypical cervical vertebra with unique features and important relations that make it easily recognisable. Its most prominent feature is the odontoid process, which is embryologically the body of the atlas (C1)1,2. It plays a...
Article

Baastrup syndrome

Baastrup syndrome (also referred to as kissing spines) results from adjacent spinous processes in the lumbar spine rubbing against each other and resulting in hypertrophy and sclerosis with focal midline pain and tenderness relieved by flexion and aggravated by extension.  Epidemiology It tend...
Article

Bamboo spine

Bamboo spine is a radiographic feature seen in ankylosing spondylitis that occurs as a result of vertebral body fusion by marginal syndesmophytes. It is often accompanied by fusion of the posterior vertebral elements as well.  A bamboo spine typically involves the thoracolumbar and or lumbosacr...
Article

Basilar invagination

Basilar invagination, also called basilar impression, is a congenital or acquired craniocervical junction abnormality where the tip of the odontoid process projects above the foramen magnum.  Terminology The terms basilar invagination and basilar impression are often used interchangeably becau...
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Basilar invagination (mnemonic)

A mnemonic to help recall the cases of basilar invagination is: PF ROACH Mnemonic P: Paget disease of bone F: fibrous dysplasia R: rheumatoid arthritis, rickets O: osteogenesis imperfecta, osteomalacia A: achondroplasia C: Chiari I and Chiari II, cleidocranial dysostosis H: hyperparathy...
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Basion-axial interval

The basion-axial interval (BAI), as the name suggests, is the horizontal distance between the basion and the posterior cortex of the axis, used in the diagnosis of atlanto-occipital dissociation injuries. It is the distance (in mm) between the basion and the superior extension of the posterior ...
Article

Basion-dens interval

The basion-dens interval (BDI), as the name suggests, is the distance between the basion and the tip of the dens, used in the diagnosis of atlanto-occipital dissociation injuries. It is the distance from the most inferior portion of the basion to the closest point of the superior aspect of the ...
Article

Batson venous plexus

Batson venous plexus (Batson veins) is a network of veins with no valves that connect deep pelvic veins draining the bladder, prostate and rectum to the internal vertebral venous plexus 1. These veins are important because they are believed to provide a route for spread of pelvic cancer metastas...
Article

Bertolotti syndrome

Bertolotti syndrome refers to the association between lumbosacral transitional vertebrae (LSTV) and low back pain, and can be an important cause in young patients. It is considered controversial and has been both supported and disputed since Mario Bertolotti first described it in 1917. Some stud...
Article

Bilateral facet dislocation

Bilateral facet dislocation is a flexion distraction type of dislocation. Pathology Mechanism It has been thought to result from hyperflexion, however, recent studies suggest a buckling force to be the cause 1. Radiographic features loss of apposition at facet joint: bilateral facet joints ...
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Block vertebra

Block vertebra is a type of vertebral anomaly where there is a failure of separation of two or more adjacent vertebral bodies. Pathology In a block vertebra, there is partial or complete fusion of adjacent vertebral bodies. Associations there is a frequent association with hemivertebrae/abse...
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Blunt cerebrovascular injury

Blunt cerebrovascular injury (BCVI) is an uncommon but serious consequence of blunt trauma to the head and neck. Epidemiology It is often part of multi-trauma with a significant series of blunt trauma CTA reporting an incidence of approximately 1% 3. A large systematic review and meta-analysis...
Article

Borden classification of dural arteriovenous fistulas

The Borden classification of dural arteriovenous fistulas (DAVF) groups these lesions into three types based upon the site of venous drainage and the presence or absence of cortical venous drainage. It was first proposed in 1995 1 and remains popular although, at the time of writing (July 2016) ...
Article

Brachial plexus

The brachial plexus is a complex neural network formed by lower cervical and upper thoracic ventral nerve roots which supplies motor and sensory innervation to the upper limb and pectoral girdle. It is located in the neck extending into the axilla posterior to the clavicle. Summary origin: ven...
Article

Brown-Séquard syndrome

Brown-Séquard syndrome is the result of a hemicord lesion (i.e damage or impairment to the left or right side of the spinal cord). Clinical presentation Due to some fibres crossing within the cord whilst others cross in the brainstem, the neurology is bilateral, namely 1:  ipsilateral ascend...
Article

Bullet shaped vertebra

Bullet shaped vertebra refers to the anterior beaking of the vertebral body. It is seen in the following conditions: mucopolysaccharidosis (Morquio disease, Hurler disease) achondroplasia  congenital hypothyroidism  See also weapons and munitions inspired signs
Article

Burst fracture

Burst fractures are a type of compression fracture related to high-energy axial loading spinal trauma that results in disruption of the posterior vertebral body cortex with retropulsion into the spinal canal. They frequenlty occur at the thoracolumbar transition zone between T11 and L1. Clinica...
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Butterfly vertebra

Butterfly vertebra is a type of vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochordal tissue between them. Pathology Associations an anterior spina bifida, with or without an anterior meninogocoele can be part ...
Article

Calcific tendinitis of the longus colli muscle

Calcific tendinitis of the longus colli muscle is an inflammatory/granulomatous response to deposition of calcium hydroxyapatite crystals in the tendons of the longus colli muscle. Clinical presentation  Patients can present with debilitating symptoms that are unrelated to the degree of calcif...
Article

Camptocormia

Camptocormia (bent spine syndrome) is a rare syndrome characterised by involuntary flexion of the thoracolumbar spine with weight-bearing which reduces when laying down, and is due to isolated atrophy of the paraspinal muscles. This condition may be associated with Parkinson disease, dystonic di...
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Castellvi classification of lumbosacral transitional vertebrae

The Castellvi classification is used for lumbosacral transitional vertebra (LSTV): type I: enlarged and dysplastic transverse (at least 19 mm) Ia: unilateral Ib: bilateral type II: pseudoarticulation of the transverse process and sacrum with incomplete lumbarisation/sacralisation; enlargemen...
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Cauda equina

The cauda equina is the collective term given to nerve roots distal to the conus medullaris, which occupy the lumbar cistern.  It is said to look like a horses tail.
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Cauda equina syndrome

Cauda equina syndrome (CES) refers to a collection of symptoms and signs that result from severe compression of the descending lumbar and sacral nerve roots. It is considered a diagnostic and surgical emergency.  Epidemiology CES is rare with prevalence estimated at approximately 1 in 65,000 (...
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Caudal epidural injection

Caudal epidural injections, or sacral hiatus epidural injections, are one of several possible spinal epidural injections.  Indications Typically, epidural injections are performed in patients who are currently not surgical candidates. The caudal injection can be performed when patients are on ...
Article

Caudal regression syndrome

Caudal regression syndrome (CRS) represents a spectrum of structural defects of the caudal region. Malformations vary from isolated partial agenesis of the coccyx to lumbosacral agenesis. Epidemiology Caudal regression syndrome is rare, with an estimated incidence of 1:7500-100,000 7,10. The ...
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Central cord syndrome

Central cord syndrome (CSS) is the most common type of incomplete spinal cord injury, accounting for ~10% of all spinal cord injuries10. As the name implies, this syndrome is the result of a contusion of the central portion of the cervical spinal cord. Epidemiology Most often CCS occurs in old...
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Cervical degenerative spondylosis - grading

A very old and reliable classification was given by Kellgren et al, for cervical degenerative changes based on findings on a lateral cervical spine radiograph. In present context it can also be applied on MRI evaluation of spine. The key parameters are osteophyte formation, intervertebral disc...
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Cervical interlaminar epidural injection

Cervical 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 cervical transforaminal epidural injections.  Indications Typically epidural injections are performed in patients with ...
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Cervical plexus

The cervical plexus is formed by the ventral (anterior) rami of the C1 to C5 nerve roots and innervates the diaphragm, provides motor supply to some neck muscles and cutaneous sensation to the skin of the head, neck and chest. Gross anatomy Roots anterior rami of C1 to C5 nerves Course runs...
Article

Cervical rib

Cervical rib is a supernumerary or accessory rib arising from the seventh cervical vertebra. They occur in ~0.5% of the population, and are more common in females. Although cervical ribs are usually asymptomatic, they are the most important anatomic rib variant clinically, because they can caus...
Article

Cervical spine

The cervical spine is the upper part of the spine extending from the skull base to the thorax at the level of the first vertebra with a rib attached to it. It normally consists of seven vertebrae. Its main function is to support the skull and maintain the relative positions of the brain and spin...
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Cervical spine floating pillar

A floating pillar, also referred as pedicolaminar fracture-separation injury, is characterised by fractures through the pedicle and lamina of a cervical spine vertebrae creating a free-floating articular pillar fragment. It is an unstable cervical spine fracture that results from hyperflexion–la...
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Cervical spine fracture classification systems

There are several cervical spine fracture classification systems: ​Anderson and D'Alonzo classification (odontoid fracture) Levine and Edwards classification (for traumatic injuries to axis) Allen and Ferguson classification (subaxial spine injuries)
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Cervical spine fractures

Cervical spine fractures can occur secondary to exaggerated flexion or extension, or because of direct trauma or axial loading. Pathology The cervical spine is susceptible to injury because it is highly mobile with relatively small vertebral bodies and supports the head which is both heavy and...
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Cervical spine injury

Cervical spine injuries can involve the cervical vertebral column, intervertebral discs and cervical spine ligaments, and/or cervical spinal cord. The cervical spine accounts for ~50% of all spinal injuries.  Epidemiology 5-10% of patients with blunt trauma have a cervical spine injury 1.  Pa...
Article

Cervical spine ligaments

Cervical spine ligaments ordered from anterior to posterior include: anterior longitudinal ligament (ALL) anterior atlanto-occipital membrane apical ligament alar ligaments (paired) cruciate ligament of the atlas longitudinal band: joins the body of the axis to the foramen magnum transver...
Article

Chalk stick fracture

Chalk stick or carrot stick fractures are fractures of a fused spine, classically seen in ankylosing spondylitis. Terminology Some authors define the chalk stick fracture as a fracture through a Pagetoid long bone (see Paget disease). Pathology They usually occur through the disco-vertebral ...
Article

Chamberlain line

Chamberlain line is a line joining the back of hard palate with the opisthion on a lateral view of the craniocervical junction. Significance It helps to recognise basilar invagination which is said to be present if the tip of the dens is >3 mm above this line. McGregor developed a modifica...
Article

Chance fracture

Chance fractures, also referred as seatbelt fractures, are flexion-distraction type injuries of the spine that extend to involve all three spinal columns. These are unstable injuries and have a high association with intra-abdominal injuries. Pathology Mechanism They tend to occur from a flexi...
Article

Charcot-Marie-Tooth disease

Charcot-Marie-Tooth (CMT) disease, also known as hereditary motor and sensory neuropathy (HMSN), is the most commonly inherited neuropathy of lower motor (to a lesser degree sensory) neurons. Clinical presentation Signs and symptoms usually become first evident in childhood. Typically this sta...
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Chordoma

Chordomas are uncommon malignant tumours that account for 1% of intracranial tumours and 4% of all primary bone tumours.  They originate from embryonic remnants of the primitive notochord (earliest fetal axial skeleton, extending from the Rathke's pouch to the coccyx). Since chordomas arise in ...
Article

Clasp-knife deformity

Clasp-knife deformity is relatively common anomaly found at the lumbosacral junction and characterized by a large midline defect of the posterior arch of the sacrum (usually S1/S2 and occasionally S3) along with hypertrophy (or overgrowth) of the spinous process of vertebra above (usually L5) 1-...
Article

Clasp-knife syndrome

Clasp-knife syndrome (also called spina bifida engagement syndrome or spina magna or long spinous process syndrome) is one of the low back pain causes. When a Clasp-knife deformity is accompanied by pain on extension secondary to protrusion of the enlarged spinous process (knife blade) into the...
Article

Classification of spinal meningeal cysts

Spinal meningeal cysts can be classified according to a system published by Nabor et. al 2: type I: extradural meningeal cyst without neural tissue type Ia: extradural spinal arachnoid cyst type Ib: sacral meningocele type II: extradural meningeal cyst containing neural tissue, e.g. Tarlov c...
Article

Clay-shoveler fracture

Clay-shoveler fractures are fractures of the spinous process of a lower cervical vertebra. They are usually a stress fracture. Clinical presentation Often these injuries are unrecognised at the time and only found incidentally years later when the cervical spine is imaged for other reasons. A...
Article

Cobb angle

The Cobb angle is used to quantify the magnitude of spinal deformities, especially in the case of scoliosis. To measure the Cobb angle, one must first decide which vertebrae are the end-vertebrae of the curve deformity (vertebrae at the upper and lower limits of the curve) and then Cobb angle f...
Article

Coccyx

The coccyx is the small triangular bone at the termination of the vertebral column which sits inferior to the apex of the sacrum. The coccyx is one leg of the tripod formed in conjunction with the ischial tuberosities for support in a seated position. Additionally, it serves as the insertion sit...
Article

Congenital absence of a spine pedicle

Congenital absence of a spine pedicle is a rare congenital condition, but awareness of its characteristic imaging appearance is important to avoid misdiagnosis. Failure to recognise this entity can lead to misdiagnosis of unilateral facet subluxation/dislocation, leading to unnecessary treatmen...
Article

Congenital lumbar spinal stenosis

Congenital lumbar spinal stenosis (CLSS) is a type of vertebral central canal stenosis and has a different epidemiology with less severe degenerative change compared to acquired/degenerative lumbar spinal stenosis.  Epidemiology CLSS tends to affect patients at a younger age (30-50 years old) ...
Article

Conus medullaris

The conus medullaris is the terminal end of the spinal cord. Gross anatomy After the cord terminates, the nerve roots descend within the spinal canal as individual rootlets, collectively termed the cauda equina. The conus medullaris most commonly terminates at the L1/2 intervertebral disc leve...
Article

Conus medullaris syndrome

Conus medullaris syndrome is caused by and injury or insult to the conus medullaris and lumbar nerve roots. It is a clinical subset of spinal cord injury syndromes. Injuries at the level of T12 to L2 vertebrae are most likely to result in conus medullaris syndrome. Pathology The conus medullar...
Article

Corduroy sign

The corduroy sign refers to a vertically oriented, thickened trabeculations seen in intraosseous haemangiomas of the spine. It is caused by replacement of the normal cancellous bone by thickened vertical trabeculae surrounded by fat marrow or vascular lacunae in intraosseous haemangiomas 2. Se...
Article

Coronal vertebral cleft

Coronal vertebral cleft refers to the presence of a radiolucent vertical defect on a lateral radiograph.   Epidemiology It is most often seen in premature male infants 1,3. As they can occur as part of normal variation (especially in the lower thoracic-upper lumbar spine of premature infants) ...
Article

Craniovertebral junction anomalies

Craniovertebral junction (CVJ) anomalies can be congenital, developmental or due to malformation secondary to any acquired disease process. These anomalies can lead to cranial nerve compression, vertebral artery compression and obstructive hydrocephalus. Pathology  The cranio-vertebral junctio...
Article

Crowned dens syndrome

The crowned dens syndrome is an inflammatory condition resulting from crystal deposition in cruciform and alar ligaments surrounding the dens, appearing as a radiopaque 'crown' surrounding the top of the dens.  It typically presents with pain and increased inflammatory markers.  Terminology Th...
Article

Cruciate ligament of the atlas

The cruciate ligament of the atlas (also known as the cruciform ligament) holds the dens in articulation at the atlanto-axial joint. It lies behind a large synovial bursa (surrounded by loose fibrous capsule) and consists of two bands: longitudinal band: joins the body of the axis to the forame...
Article

Curtain sign

The curtain sign (or draped curtain sign) in neuroimaging refers to the appearance of a vertebral body mass that extends to the anterior epidural space. The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline and is more loosely attached la...
Article

Cyst of the medullary conus

Cyst of the medullary conus is a rare benign ependymal cyst of the conus medullaris which probably relates to abnormal persistence and cystic dilatation of the ventriculus terminalis or "5th ventricle". This entity can be symptomatic and present in adulthood with bladder or bowel sphin...
Article

Dagger sign

The dagger sign is a radiographic feature seen in ankylosing spondylitis as a single central radiodense line on frontal radiographs related to ossification of supraspinous and interspinous ligaments.

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