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.
717 results found
Article
Lumbar canal stenosis
Lumbar canal stenosis is a general term that refers to the pathological narrowing of the spinal canal, nerve root canals and/or the intervertebral foramina in the lumbar spine 1-4,6,7,9,10.
Epidemiology
Lumbar canal stenosis is common, especially among individuals over 60 years old, and its pr...
Article
Laminoplasty
Laminoplasty, also known as osteoplastic reconstruction of the lamina, is a surgical procedure that involves the replacement of the lamina of the vertebral body following a laminectomy procedure in an attempt to provide better post-operative stabilization.
Indications
spinal stenosis
compress...
Article
Muhle staging system of cervical canal stenosis
The Muhle staging system is a classification system used to evaluate the severity of cervical canal stenosis.
The system was developed based on a study conducted by Muhle et al. who used kinematic MRI to assess the dynamic changes of the cervical spine in patients at different stages of degener...
Article
CT myelography
CT myelography is a myelography technique used mainly to assess for potential spinal canal stenosis when MRI is contraindicated or when dynamic imaging is required.
History
CT myelography was first performed in 1976 2.
Indications
spinal canal stenosis when MRI is contraindicated
dorsal tho...
Article
Overshunting-associated myelopathy
Overshunting-associated myelopathy, also known as Miyazaki syndrome, is a very rare form of compressive myelopathy that is a complication of intracranial hypotension due to excessive cerebrospinal fluid (CSF) diversion.
Clinical presentation
Patients present with progressive cervical myelopath...
Article
Canal-to-body ratio of Torg and Pavlov
The canal-to-body ratio of Torg and Pavlov is a method of evaluating the degree of cervical canal stenosis on lateral cervical spine radiographs.
Terminology
This ratio is variously referred to as the Torg ratio 3, the Pavlov ratio 3,4, the Torg-Pavlov ratio 5, or the canal-to-body ratio 3.
M...
Article
Lumbar nerve root anomaly classification
There are a number of systems for lumbar nerve root anomaly classification with the Neidre and MacNab classification the most commonly cited; other systems include the Postacchini classification, and the Kadish and Simmons classification 2.
Classification
Neidre and MacNab classification modif...
Article
Cysts of Hattori
Cysts of Hattori, also known as posterior mediastinal paravertebral Müllerian cysts, are mediastinal cysts of Mullerian origin, lined by ciliated non-stratified cuboidal to columnar epithelium, that occur in the posterior mediastinum.
Epidemiology
Of all mediastinal masses, ~20% (range 10–30%)...
Article
Extradural spinal cavernous malformation
Extradural spinal cavernous malformations, also known as extradural spinal cavernomas, are rare vascular malformations that occur in the spine.
This article specifically relates to extradural spinal cavernomas. For a general discussion of spinal cord cavernomas please refer to the article spin...
Article
Arthritis
Arthritis (plural: arthritides) refers to inflammation of the joints, caused by a broad range of etiologies.
Terminology
Arthropathy is a broader term referring to any disease of the joint, whereas arthritis is a type of arthropathy specifically referring to inflammation of the joint.
Patholo...
Article
Intertransversarii muscle group
The intertransversarii muscles are small and short muscles found in the deepest layer of the intrinsic back muscles extending between the transverse processes of adjacent cervical and lumbar vertebrae. The cervical intertransversarii are subdivided into seven pairs of anterior and posterior musc...
Article
Interspinales muscles
The interspinales muscles are a group of paired muscle fascicles found in the paraspinal portion of the deepest layer of the intrinsic back muscles.
Gross anatomy
The interspinales muscles extend between the spinous processes of two neighboring vertebrae. They are present throughout the entir...
Article
Middle clunal nerve entrapment
Middle clunal nerve entrapment is a potential cause of low back pain. The middle clunal nerves travel beneath the long posterior sacroiliac ligament and this is a potential space for nerve entrapment 1.
Clinical presentation
Low back pain and leg pain can be caused by entrapment of these nerve...
Article
Somatic nervous system
The somatic nervous system (SNS) is a subdivision of the peripheral nervous system which provides innervation to the somatic structures of the body, that is the parts excluding the viscera, smooth muscle, and glands.
The SNS is distributed throughout the body through somatosensory neurons withi...
Article
Ganglion impar
The ganglion impar, also know as the ganglion of Walther, is the midline autonomic ganglion located in the lower pelvis. It is the most distal convergence of the pelvic sympathetic chain which is usually located anterior to the coccyx. It can be found anywhere between the sacrococcygeal joint a...
Article
Parasympathetic nervous system
The parasympathetic nervous system (PaNS/PNS), mediated by the head and neck ganglia and pelvic splanchnic nerves, is a major division of the autonomic nervous system. It is composed of general visceral afferent and efferent axons that allow for involuntary control of bodily functions via severa...
Article
Normal imaging examples
This article lists examples of normal imaging divided by body region and system.
brain
head and neck
spine
chest
breast
gastrointestinal
genitourinary
hepatobiliary
upper limb
lower limb
pediatrics
Article
Spinal cord tuberculoma
Spinal cord tuberculomas are rare compared to intracranial tuberculomas and can be challenging to diagnose particularly in individuals who are not from endemic areas.
Epidemiology
Only 0.2% of central nervous system tuberculosis shows evidence of spinal cord involvement, and among tuberculosi...
Article
Osteolytic bone lesion
Osteolytic lesions, lytic or lucent bone lesions are descriptive terms for lesions that replace normal bone or with a vast proportion showing a lower density or attenuation than the normal cancellous bone. This comprises lesions with fatty liquid and solid soft tissue components.
Pathology
Luc...
Article
Basivertebral nerve
The basivertebral nerve supplies the vertebral endplates and can be a target for treating back pain.
Gross anatomy
The basivertebral nerve is a paired nerve arising from the sinuvertebral nerve. It ascends from its origin to enter the spinal canal, traversing centrally 1. It courses with the ...
Article
Cervical foraminal stenosis
Cervical foraminal stenosis is a common condition that is mostly asymptomatic but in some patients results in cervical radiculopathy.
Clinical presentation
Cervical foraminal stenosis is most commonly asymptomatic (found in ~20% of the population 8,10) but can result in cervical nerve root com...
Article
Thoracic spine protocol (MRI)
The MRI thoracic spine protocol encompasses a set of MRI sequences for the routine assessment of the thoracic spine.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the thoracic spine. An MR thoracic spine protocol might be combined with a cervical sp...
Article
Acute flaccid myelitis
Acute flaccid myelitis is an uncommon cause of acute flaccid paralysis similar to poliomyelitis, primarily affecting children and usually seen following a respiratory viral illness.
Epidemiology
Acute flaccid myelitis primarily affects children. Cases appear to be temporally related to respi...
Article
Cervical spine protocol (MRI)
The MRI cervical spine protocol encompasses a set of MRI sequences for the routine assessment of the cervical spine.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the cervical spine. Protocol specifics will vary depending on MRI scanner type, specif...
Article
Lumbar spine protocol (MRI)
The MRI lumbar spine protocol encompasses a set of MRI sequences for the routine assessment of the lumbar spine.
Note: This article aims to frame a general concept of an MRI protocol for the assessment of the lumbar spine. Protocol specifics will vary depending on MRI scanner type, specific har...
Article
Focal nodular marrow hyperplasia
Focal nodular marrow hyperplasia is a rare, benign condition where there is a localized conversion of red/hematopoietic from yellow/fatty bone marrow. Its main relevance is of having a pseudotumor appearance mimicking skeletal metastases on MRI 1.
Pathology
Location
Most commonly located in t...
Article
Harris ring
A Harris ring is a ring-like shadow observed at the base of the odontoid process on a lateral radiograph of the cervical spine. It is formed by the superimposition of the lateral masses of the C2 vertebra (axis) on its body.
Disruption of the Harris ring is seen in type III, and less commonly, ...
Article
Brain and Spinal Cord Injury Center score
The Brain and Spinal Injury Center (BASIC) score is a classification system for grading acute traumatic spinal cord injury based on the axial extent of intramedullary signal abnormality on T2 weighted MRI.
Classification
The BASIC score is an ordinal scale that is graded 0 to 4 1:
BASIC 0 (no...
Article
Collar sign in spondylolysis
The Collar sign in spondylolysis refers to a break in the pars interarticularis of the vertebra on oblique radiographs that can have the appearance of a collar around the Scotty dog's neck.
unilateral or bilateral
90% seen at the L5 level and less than10% noted at the L4 level1,2
65% of patie...
Article
Superior hypogastric nerve block
Superior hypogastric nerve block is a valuable tool for pain relief in the setting of uterine fibroid embolization. This procedure results in significant ischemic pain, peaking at 6-8 hours and lasting approximately 24 hours, then followed by a lesser degree of post-embolization pain which can l...
Article
Supraodontoid space
The supraodontoid space, also known as the supradental space or apical cave, is an extradural space at the anterior craniocervical junction superior to the odontoid process of C2 (dens axis).
Gross anatomy
Boundaries
The space is a cave-shaped region facing posteriorly with the following boun...
Article
Tuli classification of occipital condyle fractures
The Tuli classification of occipital condyle fractures is a clinically-oriented system for describing these injuries based on fracture displacement and ligamentous injury. It is newer than the more well-known Anderson and Montesano classification of occipital condyle fractures and allows the inc...
Article
Bow-tie sign
"Bow-tie sign" refers to the appearance of rotated facets in unilateral facet joint dislocation. Facet joint displacement coupled with a rotational deformity gives a bow-like like appearance on a lateral view radiograph of spine 1.
Article
Autonomic nervous system
The autonomic nervous system (ANS) is a subdivision of the peripheral nervous system. The autonomic system provides innervation of the involuntary muscles, i.e. myocardium and smooth muscle, and glands, through which fine control of homeostasis is maintained.
The afferent innervation of the aut...
Article
Pincer/split fracture
Pincer or split fractures are coronally oriented vertebral body fractures that involve the superior and inferior vertebral body endplates but do not involve the anterior or posterior cortices.
Clinical Presentation
Pincer fractures may present in the setting of trauma, with an axial loading m...
Article
Kemp test
The Kemp test (also known as the quadrant test and extension-rotation test) is a provocative test on clinical examination that has been described as being useful for diagnosing pain related to facet joint pathology, e.g. arthropathy but is of limited diagnostic accuracy 1. The patient performs c...
Article
Elsberg syndrome
Elsberg syndrome is an established but rarely recognized cause of cauda equina syndrome and lower thoracic myelitis, associated with a presumed infectious etiology.
Epidemiology
Elsberg syndrome is likely responsible for 10% of combined cauda equina syndrome and myelitis 1.
Clinical presenta...
Article
Axial spondyloarthritis
Axial spondyloarthrititis (SpA) is a clinical subset of the seronegative spondyloarthritides that present primarily with back pain and morning stiffness. There is a long delay, on average 14 years, between symptoms onset and diagnosis 1.
Epidemiology
The prevalence of axial SpA is ~1% 1. Age o...
Article
Hip spine syndrome
Hip spine syndrome is one term used to describe the clinical association between hip osteoarthritis and degenerative lumbar spinal canal stenosis due to overlapping pain distribution.
Clinical presentation
Patients with hip spine syndrome have hip and lumbar spine degeneration and present wit...
Article
Trefoil appearance of spinal canal
A trefoil appearance of spinal canal (sometimes termed as a cloverleaf spinal canal appearance) is a particular appearance that is of congenital or acquired etiology. This is mainly described in the lumber region and can result in narrowing of the lateral recesess as well as at times involvement...
Article
Lumbar spinal stenosis (grading)
Lumbar spinal stenosis grading refers to systems for classifying the severity of lumbar canal stenosis (central spinal canal narrowing) around the cauda equina nerve roots.
Usage
The two most popular systems, both applied to visual assessment of MRI, are the Lee grading system, and the Schiza...
Article
Anterior instrumentation and fusion (scoliosis)
Anterior instrumentation and fusion is a surgical procedure used in patients with adolescent idiopathic scoliosis to correct vertebral curvature. This technique is preferred to posterior instrumentation and fusion in skeletally immature patients with a Lenke 5C thoracolumbar or lumbar adolescent...
Article
Scoliosis surgery (overview)
Scoliosis surgery is indicated when conservative management has failed.
Indications
Cobb angle ≥45º (skeletally immature) or ≥40-50º (skeletally mature) 1,2
progressive scoliosis deformity
spinal functional compromise
pain not responsive to non-operative treatment
pulmonary function compro...
Article
Degenerative spinal instability
Degenerative spinal instability is frequent although somewhat controversial clinical entity with evolving theories on its clinical relevance, in particular, its role as a causative factor of low back pain (LBP). While radiographic instability may be evident, this does not always correlate with t...
Article
Spinal instability (overview)
Spinal instability is a broad term with no generally agreed-upon definition but can be thought of the potential for or actual abnormal segmental spinal motion.
Terminology
Spinal microinstability refers to abnormal segmental movement without bony changes 1.
Pathology
Spinal instability is ...
Article
Discectomy
Discectomy is the most common surgery for lower back pain performed for the treatment of disc herniations. It is often combined with other spinal procedures such as laminotomy or foraminotomy or artificial disc replacement and other forms of spinal fusion. Discectomy techniques can be generally ...
Article
Anterior vertebral body tether (AVBT)
Anterior vertebral body tethering (AVBT) is a fusionless technique for treating and managing idiopathic scoliosis in skeletally immature patients to reduce the typical side effects of rigid posterior fusion (such as loss of spinal motion and risks adjacent segment degeneration later in life) 1,3...
Article
Vertical expandable prosthetic titanium rib (VEPTR) procedure
Vertical expandable prosthetic titanium rib (VEPTR) procedure is a surgical technique that was initially developed to treat thoracic insufficiency syndrome and then it was used in congenital scoliosis with rib abnormalities, and has since been successfully used to treat early-onset scoliosis wit...
Article
In situ contouring
In situ contouring is a surgical technique used in thoracolumbar scoliosis surgery and thoracolumbar fracture reduction and fixation.
Procedure
Thoracolumbar scoliosis surgery
The key of this technique is to " make the rod take the shape of the spine and then to make the spine take the shape...
Article
adrenal gland
In situ spinal fusion is, as the name suggests, where fusion is performed without a change in alignment. It is a technique used to treat:
isthmic spondylolisthesis 1
osteogenesis imperfecta 2
Article
Posterior dynamic lumbar stabilization
Posterior dynamic lumbar stabilization is an alternative instrumented method to rigid spinal fusion aiming to improve segmental stability. Purported advantages of this technique include reduced posterior element and intervertebral disc loading reducing symptoms and potentially allowing for disc ...
Article
Stork test
The Stork test (also known as the Gillet test) is a clinical test used to assess the movement (intrapelvic motion) of the sacroiliac joint between the innominate bone and sacrum. It can be useful in evaluating suspected sacroiliac joint pathology / dysfunction.
It involves placing the examiner'...
Article
Lumbar disc arthroplasty
Lumbar disc arthroplasty is a procedure involving the replacement of lumbar intervertebral discs with artificial discs to manage lower back pain.
Similar to its cervical counterpart (cervical disc arthroplasty), it is an alternative to fusion procedures as a means of maintaining an increased ra...
Article
Implant migration
Implant migration or hardware migration refers to the displacement of an implant or component away from its designated position and is associated with hardware failure and loosening. Examples of implant migration include screw break out or screw back out, cage extrusion, inlay extrusion, choledo...
Article
Osseous surgical spinal fusion
Osseous surgical spinal fusion refers to spinal fusion surgery with bone grafts, bone graft supplements or bone graft substitutes.
Osseous spinal fusion eventually supplies the best stability for the respective spinal segment and most types of spinal fusion surgeries are directed to establish a...
Article
Posterior instrumentation and fusion (scoliosis)
Posterior instrumentation and fusion is a surgical technique to improve spinal curvature in scoliosis patients.
Procedure
The vertebral column is manipulated into the desired position and held in place with metalwork namely pedicle screws and/or hooks transfixed with rods with or without in si...
Article
Spinal instrumentation hardware
Spinal instrumentation hardware refers to various types of implants used for fixation in spinal surgery. They can be used in various combinations and include wires, clamps, screws, different plate-screw and rod-screw interfaces, intervertebral prostheses and disk replacements.
Cervical spine in...
Article
Congenital scoliosis
Congenital scoliosis refers to scoliosis resulting from a congenital abnormality of the vertebra, e.g. a segmentation or fusion defect.
Terminology
There are several definitions of congenital scoliosis. Some authors include neurological congenital causes. In this article, our focus will only ...
Article
Neuromuscular scoliosis
Neuromuscular scoliosis is a term that can be used to describe scoliosis that is caused by underlying brain, spine or muscular conditions. While the underlying conditions can be a very broad group of disparate conditions, they tend to result in similar spinal curves.
Radiographic features
Neur...
Article
Interspinous device
Implantation of interspinous devices is one option for treating lumbar canal stenosis and other causes of low back pain. These devices attempt to produce lumbar flexion by distracting the lumbar spinous processes restoring height and resulting in tightening of the thickened ligamentum flavum, an...
Article
Hardware failure
Orthopedic implant or hardware failure refers to the failure of the implant to live up to its expected requirements with respect to the manufacturer's or the surgeon's allegations. This includes any complication directly related to the implant such as wear, fractures, dissociations and dislocati...
Article
Craniocervical fixation
Craniocervical fixation, instrumentation or occipitocervical fusion refer to surgical fixation techniques with the goal to stabilize the craniocervical junction.
Indications
Craniocervical fixation is indicated in the setting of craniocervical instability including 2,3:
iatrogenic craniocervi...
Article
Atlantoaxial fixation
Atlantoaxial fixation refers to various surgical techniques to stabilize the atlantoaxial complex.
History and etymology
The first effort of an atlantoaxial stabilization was made by Mixter and Osgood in 1910 by fixation of the spinous processes with a heavy silk thread 1,2.
Posterior cervic...
Article
Odontoid process fixation
Odontoid process fixation or odontoid process repair refers to the surgical fixation of an odontoid fracture.
Anterior odontoid screw fixation is performed with single and double screw techniques, non-cannulated and cannulated screws, and uni- or bicortical fixation techniques.
Odontoid plate ...
Article
Osteoporotic vs pathological vertebral fractures
Discriminating between acute osteoporotic and pathological vertebral fractures is sometimes challenging. This may be especially true in the elderly population, in which both osteoporosis and malignant disease often co-occur, and vertebral fractures of both kinds are common and indeed may coexist...
Article
Oblique lumbar interbody fusion (OLIF)
Oblique lumbar interbody fusion (OLIF) is one of several techniques used in lumbar interbody fusion. It provides minimally invasive access to the disc space, passing between the peritoneum and the psoas muscles.
Indications
Indications for the procedure generally overlap with those of LLIF and...
Article
Posterior cervical fusion
Posterior cervical fusion refers to a surgical spinal fusion technique of the cervical spine for conditions requiring posterior stabilization. It might be done for the management of cervical spine fractures or combined with spinal decompression techniques such as laminectomy or laminotomy.
Hist...
Article
Posterior sacroiliac ligament
The posterior (a.k.a. dorsal) sacroiliac ligament (TA: ligamentum sacroiliacum posterius) is a very strong ligament important in stabilizing the sacroiliac joint.
Gross anatomy
Some texts state that the posterior sacroiliac ligaments have two components; a more superior part, the short posteri...
Article
Complications of spinal surgery
Complications of spinal surgery are common and can occur at different time intervals after the surgery. Some of them are related to instrumentation, the procedure and/or the approach others are not. Anyhow, it is essential for the radiologist to be aware of them in the assessment of radiographs,...
Article
Paraspinal muscles
The paraspinal muscles (PSM) , also known as paravertebral muscles, is a descriptive term given to those muscles that closely surround the spine, primarily the thoracolumbar spine. There has been great research interest in using the cross-sectional area of these muscles as a measure of overall m...
Article
Laminotomy
A laminotomy is a spinal decompression procedure with partial removal of the vertebral arch usually at its base. Laminotomies might be combined with other spinal procedures such as discectomy or spinal fusion procedures. If a laminotomy is combined with a foraminotomy, then the procedure is call...
Article
Cervical disc arthroplasty
Cervical disc arthroplasty is a procedure involving the replacement of degenerative cervical intervertebral discs with artificial discs to enable decompression of the cervical spinal cord.
This procedure is an alternative to anterior cervical discectomy and fusion (ACDF) and avoids the loss o...
Article
Posterolateral lumbar fusion
Posterolateral lumbar fusion is an alternative technique to lumbar interbody fusion and can be a primary procedure or performed after lumbar laminectomy for spinal decompression to aid in stability after disruption of the posterior tension band. Posterior instrumentation via pedicle screws and r...
Article
Lumbar interbody fusion (overview)
Lumbar interbody fusion is a common technique that aims for osseous fusion after discectomy.
There are anterior and posterior approaches (relative to the transverse process), some of which require additional instrumentation, and none of which have been demonstrated to be clinically superior wi...
Article
Rule of Spence
The Rule of Spence is a radiologic method to evaluate the likelihood of injury to the transverse atlantal ligament (TAL) on an open mouth AP (“peg”) radiograph. As originally framed, if the combined projection of the lateral masses of the atlas is more than 6.9 mm beyond the lateral masses of th...
Article
Facet joint tropism
Facet joint tropism refers to a situation where there is a difference in the orientation/angle of facet joints (i.e. between the left and right sides) with respect to each other in the sagittal plane. This can lead to unequal biomechanical forces on the facet joints and intervertebral disc durin...
Article
Dedifferentiated chordoma
Dedifferentiated chordomas are biphasic malignant tumors composed of notochordal and high-grade sacomatous components.
Epidemiology
Dedifferentiated chordomas are very rare tumors that might be seen in recurrences or after radiotherapy 1-3.
Diagnosis
The diagnosis is based on typical imaging...
Article
Idiopathic scoliosis
Idiopathic scoliosis describes scoliosis that has no clinically or radiologically identifiable underlying cause. It is the dominant type of scoliosis with ~80% of all scolioses being idiopathic.
Pathology
Idiopathic scoliosis can be classified by age into:
adolescent idiopathic scoliosis (>11...
Article
CT thoracic spine (protocol)
The CT thoracic spine or T-spine protocol serves as an examination for the assessment of the thoracic spine. As a separate examination, it is often performed as a non-contrast study. It might be combined or simultaneously acquired with a CT chest or CT chest-abdomen-pelvis as part of a trauma or...
Article
Backfill
Backfill refers to intra-articular high signal intensity on T1 weighted images seen in axial spondylarthritis within the sacroiliac joint filling up excavated bone erosions 1. It has been characterized as a complete loss of the cortical bone within the sacroiliac joint at the anticipated locatio...
Article
Rigid spine
A rigid spine is a condition that is characterized by the ossification and/or fusion of spinal segments thus leading to a change in biomechanics. The shock absorption capabilities of normal intervertebral discs, as well as the elasticity of ligaments, is eliminated thus making the rigid spine mo...
Article
Discoligamentous injury
Discoligamentous injuries are severe spinal injuries in which the intervertebral disc and the intervertebral ligamentous structures are involved. They include cervical, thoracic or lumbar anterior tension band injuries as well as translational injuries.
Terminology
The term transdiscal fractur...
Article
Segmental endplate angles in spine injuries
Segmental endplate or segmental kyphosis angles include the monosegmental and bisegmental endplate angle as well as the vertebral compression angle and play a role in the stability assessment after spinal injuries.
The following angles might be used 1-3:
monosegmental endplate angle or Gardner...
Article
Braid-like sign (spinal sarcoidosis)
The braid-like sign is an imaging pattern of sarcoidosis spinal cord involvement. It is characterized by a ventral subpial enhancement in the spinal cord.
Article
Subarticular zone stenosis
Subarticular zone stenosis is a form of spinal stenosis where there is narrowing of the subarticular zone, including the lateral recess. This may occur with or without other forms of spinal stenosis.
Pathology
Nerve root compression at the lateral recess can occur in two morphological forms:
...
Article
Dialysis-related spondyloarthropathy
Dialysis-related spondyloarthropathy is a relatively uncommon complication of renal dialysis. It is part of the spectrum of dialysis-related amyloidosis.
Pathology
Thought to be mainly due to extensive deposition of beta-2 microglobulin (amyloid-like substance) within the spine (especially in...
Article
Lateral atlantodental instability
Lateral atlantoaxial instability is a subtype of atlantoaxial subluxation, and is a poorly understood entity that may be encountered in post-traumatic and rheumatic patients with equal frequency to established sagittal plane atlantoaxial subluxation 1.
There is limited information regarding cl...
Article
Odontoid process agenesis
Odontoid process agenesis is rare, occurring due to a lack of failure of ossification of the odontoid process. It is seen in patients with spondyloepiphyseal and spondylometaphyseal dysplasia 1,2.
Radiographic features
Plain radiograph
On plain film, odontoid process agenesis appears as a sli...
Article
Jail bar sign (vertebral hemangioma)
The jail bar sign refers to the vertically striated appearance seen in vertebral hemangiomas due to thickening of the bony trabeculae. It is the sagittal and coronal correlate of the polka-dot sign observed on axial imaging.
It is caused by replacement of normal cancellous bone by coarse, scler...
Article
Anderson and Montesano classification of occipital condyle fractures
The Anderson and Montesano classification is a widely used system for describing occipital condyle fractures. It divides injuries into three types based on morphology and mechanism of injury 1-5.
Classification
type I: impacted type occipital condyle fracture
morphology: comminution of the co...
Article
V sign (disambiguation)
Signs inspired by the letter V have been described in several different pathologies:
inverted V sign (pneumoperitoneum)
inverted V sign (spinal cord)
Naclerio V sign (pneumomediastinum)
V sign (interphalangeal joint subluxation)
Article
Gehweiler classification of atlas fractures
The Gehweiler classification of atlas fractures described 5 types of fractures of the atlas. In addition, Dickman classified injuries of the transverse atlantal ligament (a.k.a. transverse band of the cruciform ligament) which has been incorporated into this classification system.
type 1: fract...
Article
Traynelis classification of atlanto-occipital dislocations
The Traynelis classification of atlanto-occipital dislocations describes injuries of the atlanto-occipital joint according to the displacement of the occipital condyles relative to the atlas:
type I: anterior displacement
type II: longitudinal distraction (superior-inferior displacement)
type...