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Split fat sign

The split fat sign is feature that can be seen typically on MRI images with peripheral nerve sheath tumors. It is seen as a fine rind of fat around the lesion. It is best appreciated on T1 weighted images 1. On coronal or sagittal images (i.e.images along the direction of the nerve) a tapered ri...

Spondylodiscitis

Spondylodiscitis, also referred to as discitis-osteomyelitis, is characterized by infection involving the intervertebral disk and adjacent vertebrae. Epidemiology Spondylodiscitis has a bimodal age distribution, which many authors consider essentially as separate entities: pediatric older po...

Spondylolisthesis

Spondylolisthesis denotes the slippage of one vertebra relative to the one below. Spondylolisthesis can occur anywhere but is most frequent, particularly when due to spondylolysis, at L5/S1 and to a lesser degree L4/L5. Terminology Although etymologically it is directionless (see below) and c...

Spondylolisthesis grading system

A commonly adopted method of grading the severity of spondylolisthesis is the Meyerding classification. It divides the superior endplate of the vertebra below into 4 quarters. The grade depends on the location of the posteroinferior corner of the vertebra above. This classification was original...

Spondylolisthesis Wiltse classification

Spondylolisthesis can be classified according to broad etiologies as described by Wiltse in 1981 1. Typically when reporting studies with spondylolisthesis the Wiltse type is merely stated without referring to its number, whereas the grade of spondylolisthesis is explicitly stated: e.g. "Grade 1...

Spondylolysis

Spondylolysis is a defect in the pars interarticularis of the neural arch, the portion of the neural arch that connects the superior and inferior articular facets. It is commonly known as pars interarticularis defect or more simply as pars defect. Epidemiology Spondylolysis is present in ~5% ...

Spondyloptosis

Spondyloptosis is a term to denote grade V spondylolisthesis - a vertebra having slipped so far with respect to the vertebra below that the two endplates are no longer congruent. It is usually anterolisthesis of L5 on S1 but can be seen elsewhere rarely 1,2.

Spondylosis

Spondylosis is used as a broad descriptive term referring to degeneration of the spinal column from any cause. History and etymology It derives from the the Ancient Greek term σπόνδυλος (spóndylos) meaning "a vertebra", See also spondylolisthesis spondylolysis

Straight back syndrome

Straight back syndrome refers to decreased thoracic kyphosis ("flattening") and decreased anteroposterior thoracic diameter, such that there is compression of cardiovascular or bronchial structures. It should not be confused with flat back syndrome, which refers to decreased lumbar lordosis, o...

Subacute combined degeneration of the cord

Subacute combined degeneration of the cord (SACD) is caused by vitamin B12 deficiency. Epidemiology Most common in patients older than 40 and especially older than 60 7. Clinical presentation The clinical presentation of SACD is usually with loss of vibration and proprioception in the hands...

Subluxed facet joint

Subluxed facet joint is the mildest form of facet dislocation in which the ligamentous injury leads to partial uncovering of facet joint (c.f. complete uncovering in perched facet). This results in mild anterior displacement of one vertebral body on another (anterolisthesis).

Suboccipital muscle group

The suboccipital muscle group contains four paired muscles, three of which pairs belong to the suboccipital triangle. These muscles all lie below the occipital bone and are responsible for postural support of the head, as well as extension, lateral flexion and rotation. As these muscles are smal...

Sugar coating

The so-called "sugar coating" or zuckerguss (German for sugar icing) is seen in post-contrast images of the brain and spinal cord in patients with leptomeningeal drop metastases or leptomeningeal carcinomatosis. It is seen both as a result of CNS involvement from distant primaries as well as dir...

Sulcal artery

Sulcal arteries are penetrating branches from the anterior spinal artery and extend posteriorly through the anterior median fissure of the spinal cord. The sulcal arteries supply the anterior two-thirds of the spinal cord at any cross-sectional level. Successive sulcal arteries generally altern...

Supraspinous ligament

The supraspinous ligament runs along the tips of adjacent spinous processes and is particularly thick in the cervicothoracic region. Above the level C7 spinous process the ligament no longer directly attaches to the spinous process but rather continues as the nuchal ligament up to its attachment...

Swischuk line

The Swischuk line is helpful in differentiating pathological anterior displacement of the cervical spine from physiological displacement, termed pseudosubluxation. Measurement the line is drawn from anterior aspect of posterior arch of C1 to anterior aspect of posterior arch of C3 the anterio...

Sympathetic chain

The sympathetic chain is a component of the autonomic nervous system and is composed of general visceral afferent and efferent axons that allow for involuntary control of bodily functions via the hypothalamus. The overarching function of the sympathetic system is to control the 'fight, fright o...

Syndesmophyte

Syndesmophytes are calcifications or heterotopic ossifications inside a spinal ligament or of the annulus fibrosus. They are seen in only a limited number of conditions including: ankylosing spondylitis ochronosis fluorosis Radiographic features Appearance on plain radiographs comprises v...

Synovial cyst

Synovial cysts are para-articular fluid-filled sacs or pouch-like structures containing synovial fluid and lined by synovial membrane. They can occur around virtually every synovial joint in the body and also around tendon sheaths and bursae. Communication with the adjacent joint may or may not ...

Syrinx terminology

There are specific terms used when describing a syrinx or other cystic lesions within the spinal cord 1: hydromyelia: fluid accumulation/dilatation within the central canal, therefore, lined by ependyma syringomyelia: cavitary lesion within cord parenchyma, of any cause (there are many); locat...

Systemic lupus erythematosus (CNS manifestations)

Central nervous system manifestations of systemic lupus erythematosus (CNS lupus) describe a wide variety of neuropsychiatric manifestations that are secondary to systemic lupus erythematosus (SLE) in the central nervous system (CNS). For a general discussion, and for links to other system spec...

T11 vertebra

T11 is an atypical thoracic vertebra. In contrast to typical thoracic vertebrae, it contains a single costal facet that articulates with the atypical eleventh rib. There are no facets on the transverse processes.

T12 vertebra

T12 is an atypical thoracic vertebra. In contrast to typical thoracic vertebrae, it contains a single costal facet with no facets on transverse processes.

T1 vertebra

T1 is an atypical thoracic vertebra. In contrast to typical thoracic vertebrae, it contains a complete facet for the 1st rib and a demifacet for the 2nd rib. It contains lips on the upper surface of the body. T1 also has a spinous process more horizontal than other thoracic vertebrae.

Tabes dorsalis

Tabes dorsalis is a form of tertiary late neurosyphilis in which there is demyelination of the posterior columns of the spinal cord. For a general discussion, and for links to other system specific manifestations, please refer to the article on syphilis. Clinical presentation Patients presen...

Tailgut duplication cyst

Tailgut duplication cysts, also known as retrorectal cystic hamartomas, are rare congenital lesions that are thought to arise from vestiges of the embryonic hindgut. Epidemiology There is a recognised strong female predilection. While it can present at any age, presentation is usually at arou...

Tarlov cyst

Tarlov cysts, also called perineural cysts, are CSF filled dilatations of the nerve root sheath at the dorsal root ganglion (posterior nerve root sheath). These are type II spinal meningeal cysts that are, by definition, extradural but contain neural tissue. Epidemiology They occur in ~5% of t...

Tectorial membrane of the spine

The tectorial membrane is the thin superior continuation of the posterior longitudinal ligament from the body of the axis. It joins the axis body to the clivus on the anterior half of the foramen magnum, and ascends as high as the spheno-occipital synchondrosis and laterally extends to the hypog...

Terminal myelocystocele

Terminal myelocystoceles are an uncommon form of spinal dysraphism representing marked dilatation of the central canal of the spinal cord, herniating posteriorly through a dorsal spinal defect. The result is a skin-covered mass in the lower lumbar region, consisting of an ependyma-lined sac. E...

Tethered cord

Tethered spinal cord syndrome, also known as an occult spinal dysraphism sequence, is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column. Clinical presentation The condition is closely linked to spina bifida, and as such pre...

Third condyle

The third condyle (also known as condylus tertius or median occipital condyle) is a rare anatomic variant of the occipital condyles. It is a small separate ossicle at the anteromedial margin of the occipital condyle formed by the failure of the embryonic proatlas (4th occipital sclerotome) to un...

Thoracic anatomy

Thoracic anatomy encompasses the anatomy of all structures of the thoracic cavity. This anatomy section promotes the use of the Terminologia Anatomica, the global standard for correct gross anatomical nomenclature.

Thoracic spine

The thoracic spine forms the middle part of the vertebral column. It extends from below C7 on the cervical spine to above L1 on the lumbar spine. There are 12 thoracic vertebra, termed T1-T12 (some older doctors and texts refer to the dorsal spine and D1-D12). The thoracic spine is unique due ...

Thoracic spine (AP view)

The thoracic spine AP view images the thoracic spine, which consists of twelve vertebrae. It is utilized 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 imag...

Thoracic spine (lateral view)

The thoracic spine lateral view images the thoracic spine, which consists of twelve vertebrae. It is utilized in many imaging contexts including trauma, postoperatively, and for chronic conditions. It is used in conjunction with the thoracic spine AP view to complete a thoracic spine series. P...

Thoracic spine series

The thoracic spine series is comprised of two standard projections along with a range of additional projections depending on clinical indications. The series is often utilized in the context of trauma, postoperative imaging and for chronic conditions. Radiographs of the thoracic spine are consi...

Thoracolumbar injury classification and severity score (TLICS)

The thoracolumbar injury classification and severity score (TLICS), also sometimes known as the thoracolumbar injury severity score (TISS), was developed by the Spine Trauma Group in 2005 to overcome some of the perceived difficulties regarding the use of other thoracolumbar spinal fracture clas...

Thoracolumbar spinal fracture classification systems

The two most commonly currently used thoracolumbar spinal fracture classification systems are the AO classification and the TLICS although a number of other classification systems have been proposed over the years 1. Each has benefits and drawbacks and each incorporates various features in an at...

Three column concept of spinal fractures

The three column concept of thoracolumbar spinal fractures was initially devised by Francis Denis and presently CT is mandatory for an accurate classification. While initially developed for classification of thoracolumbar spinal fractures, it can also be applied to the lower cervical spine 3 as...

Tight filum terminale syndrome

Tight filum terminale syndrome is caused by incomplete involution of the distal spinal cord during embryogenesis. This leads to development of an abnormally thickened filum terminale, which may be associated with lipomas or cysts within the filum. Tight filum terminale syndrome is always associ...

Toothpaste sign

The toothpaste sign in spinal imaging represents an extrusion of an intervertebral disk into the epidural space. It is called after the shape of extruded material relatively to the parent disk in a sagittal plane.

Torticollis

Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group. Pathology Torticollis can be acute (<1 week) or chronic (...

Tramp-stamp edema

Tramp-stamp edema is a colloquial term used by some radiologists to denote posterior lumbar subcutaneous edema. The term is used to describe edema in the distribution seen with lower back tattoos, usually in young women, which are known pejoratively as tramp-stamps. This edema is thought to be...

Transforaminal lumbar interbody fusion (TLIF)

Transforaminal lumbar interbody fusion (TLIF) is a spinal fusion procedure performed as an alternative to posterior lumbar interbody fusion (PLIF) when posterior decompression of the spinal canal is not required 1. A facetectomy is usually performed followed by a discectomy and insertion of in...

Transforaminal nerve root injection

Transforaminal nerve root injfection is performed for radicular pain treatment and diagnosis. See spinal interventional procedures for complications and equipment. cervical spine thoracic spine lumbar spine The desired needle tip position is just lateral to the pedicle immediately below the...

Transitional vertebra

Transitional vertebra is one that has indeterminate characteristic and features of vertebrae from adjacent vertebral segments. They occur at the junction between spinal morphological segments: atlanto-occipital junction atlanto-occipital assimilation: complete or partial fusion of C1 and the o...

Transpyloric plane

The transpyloric plane, also known as Addison's plane, is an imaginary axial plane located midway between the jugular notch and superior border of pubic symphysis, at approximately the level of L1 vertebral body. It an important landmark as many key structures are visualized at this level, altho...

Transverse myelitis

Acute transverse myelitis (ATM) is an inflammatory condition affecting both halves of the spinal cord and associated with rapidly progressive motor, sensory, and autonomic dysfunction. It is mostly imaged with MRI, which generally shows a long segment (3-4 segments or more) of T2 increased sign...

Transverse process fracture

Transverse process fractures are a common sequelae of trauma, although they are considered a minor and stable lumbar spine fracture. There is strong association between transverse process fractures and other traumatic injuries. Pathology Transverse process fracture most commonly occur in the u...

Transversospinalis group

The transversospinalis group is the deep layer of the intrinsic back muscles. These muscles lie between the transverse and spinous processes and are grouped by length of the fascicles, as well as region covered. The groups are rotatores, multifidus, and semispinalis. Gross anatomy Rotatores T...

Traumatic spinal cord injury

Traumatic spinal cord injury can manifest as a wide variety of clinical syndromes resulting from damage to the spinal cord or its surrounding structures. It can result from minor injury if the spine is weakened from disease such as ankylosing spondylitis or if there is pre-existing spinal stenos...

Tuberculosis

Tuberculosis encompasses an enormously wide disease spectrum affecting multiple organs and body systems predominantly caused by the organism Mycobacterium tuberculosis. A small proportion can also be caused Mycobacterium bovis. Epidemiology Although tuberculosis continues to be very common in...

Tuberculosis (musculoskeletal manifestations)

Musculoskeletal tuberculosis is always secondary to a primary lesion in the lung. Epidemiology The prevalence of the disease is around 30 million globally and 1-3% of the 30 million have involvement of their bones and/or joints. Mycobacterium tuberculosis is responsible for almost all of the c...

Tuberculous spondylitis

Tuberculous spondylitis, also known as Pott disease, refers to vertebral body osteomyelitis and intervertebral discitis from tuberculosis (TB). The spine is the most frequent location of musculoskeletal tuberculosis, and commonly related symptoms are back pain and lower limb weakness/paraplegia....

Typical cervical vertebrae

Of the seven cervical vertebrae, C3 through C6 have typical anatomy, while C7 looks very similar. C1 (atlas) and C2 (axis) have very distinct anatomical features. For a basic anatomic description of the structure a generic vertebra, see vertebrae. Gross anatomy small, oval-sized vertebral bodi...

Typical thoracic vertebrae

Given the twelve thoracic vertebrae are largely similar, most are considered typical thoracic vertebrae with the exceptions T1 and T9 to T12. For a basic anatomic description of the structure of typical vertebrae, see vertebrae. Gross anatomy Relative to cervical and lumbar vertebrae, thoracic...

Ultrasound-guided spinal anesthesia

With the growing incidence of obesity in the western world, ultrasound-guided anesthesia is becoming more common. Spinal anesthesia is traditionally administered by identifying relevant surface anatomy and imaging is rarely used for pre-procedural identification of structures. Indications low...

Uncinate process of the cervical spine

The uncinate process of the cervical spine is a hook-shaped process found bilaterally on the superolateral margin of the cervical vertebral bodies of C3-C7. The uncinate processes are more anteriorly positioned in the upper cervical spine and more posteriorly location in the lower cervical spin...

Uncovertebral joint

Uncovertebral joints, also called Luschka’s joints, are seen bilaterally between adjacent cervical vertebrae, identified by the cat ear shaped uncinate processes of the C3-7 vertebrae (C1 and C2 have no uncinate processes). Gross anatomy Articulations The articulation forms between the uncina...

Unfused spinous process

Unfused spinous process, which is really failure of fusion of the neural arch, is a relatively common anatomical variant and is part of the spectrum of spina bifida occulta. This should be differentiated from accessory ossicles of the spinous process, which appear after non-fusion of the secon...

Unilateral facet dislocation

Unilateral facet dislocation is a relatively stable type of facet dislocation. Pathology Mechanism Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or...

Vanishing vertebrae

Vanishing vertebrae is a rare ischemic manifestation of sickle cell disease, in which a completely infarcted vertebral body literally disappears or vanishes, as a result of infarction. In the few reported cases, the posterior elements remain intact. See also codfish or h-shaped vertebrae ante...

Ventral cord herniation

Ventral cord herniation, also known by a variety of other terms such as spontaneous thoracic cord herniation or idiopathic spinal cord herniation, is a rare cause of focal myelopathy due to herniation of the thoracic cord through a dural defect. Post surgical cord herniation can occur at any l...

Ventral cord syndrome

Ventral cord syndrome (also known as anterior cord syndrome) is one of the incomplete cord syndromes and affects the anterior parts of the cord resulting in a pattern of neurological dysfunction dominated by motor paralysis and loss of pain, temperature and autonomic function. Anterior spinal ar...

Ventral horn

The ventral horn of the spinal cord is one of the grey longitudinal columns found within the spinal cord. It contains the cell bodies of the lower motor neurones which have axons leaving via the ventral spinal roots on their way to innervate muscle fibers. Gross anatomy On transverse section o...

Ventriculus terminalis

The ventriculus terminalis or terminal ventricle of Krause, also known as the 5th ventricle, is an ependymal-lined fusiform dilatation of the terminal central canal of the spinal cord, positioned at the transition from the tip of the conus medullaris to the origin of the filum terminale. It re...

Vertebra

The vertebra (plural: vertebrae) is the fundamental segmental unit of the vertebral column (also know as the spine). Gross anatomy Vertebrae, apart from those that are atypical, have a similar basic structure which can be described as an anterior vertebral body and a posterior neural (or verte...

Vertebral anomalies

The vertebral column is affected by a range of anatomical variants of the body and/or neural arch as well as accessory ossicles. Knowledge of basic vertebral anatomy and ossification is essential for describing and understanding the range of anomalies. Variant anatomy Vertebral body hemiverte...

Vertebral artery

The vertebral arteries (VA) are paired arteries, each arising from the respective subclavian artery and ascending in the neck to supply the posterior fossa and occipital lobes, as well as provide segmental vertebral and spinal column blood supply. Summary origin: branches off the 1st part of t...

Vertebral artery loop formation

Vertebral artery loop formations occur when a portion of the vertebral artery contains an unusual coil. It can be a rare anatomical variant or can be acquired. Epidemiology Vertebral artery loops tend to be mostly diagnosed in the 5th and 6th decades. Its prevalence is uncertain but is thought...

Vertebral body mass

The differential diagnosis for a vertebral body mass is broad and may range from a completely benign, sclerotic enostosis (bone island) to a malignant primary bone tumor. Classification Broadly, these lesions can be separated into: non-neoplastic lesions primary bone tumors secondary metast...

Vertebral body squaring (differential)

Vertebral body squaring refers to the loss of normal concavity of the anterior border. It is seen in a variety of conditions including: Differential diagnosis Ankylosing spondylitis Ankylosing spondylitis is the most common cause of vertebral body squaring. It usually involves multiple level...

Vertebral hemangioma

Vertebral hemangiomas are the most common benign vertebral neoplasms. They are usually asymptomatic and incidentally detected due to their characteristic features on imaging for other reasons. Rarely, they can be locally aggressive (see: aggressive vertebral hemangioma). Please refer on the art...

Vertebral lesion (differential)

Differential diagnosis of vertebral lesions includes: Lesion originating in vertebral body intraosseous hemangioma metastases Paget disease multiple myeloma Osteonecrosis vertebral body osteomyelitis lymphoma plasmacytoma giant cell tumor Langerhans cell histiocytosis fibrous dyspl...

Vertebral levels (anatomical landmarks)

Many vertebral levels are associated with key anatomical landmarks. Below is a summary of vertebral levels and associated internal or surface anatomy. Vertebral Level: C3 hyoid bone C4 bifurcation of common carotid artery thyroid cartilage C6 cricoid cartilage trachea begins (end of la...

Vertebral metastases

Vertebral metastases represent the secondary involvement of the vertebral spine by haematogenously-disseminated metastatic cells. They must be included in any differential diagnosis of a bone lesion in a patient older than 40 years. This article will focus only on the metastasis involving the b...

Vertebral pneumatocyst

Vertebral pneumatocysts are gas-filled cavities within the spinal vertebrae. They are most common at cervical levels. In general, vertebral pneumatocysts are less common than intraosseous pneumatocysts in the pelvis, especially adjacent to the sacroiliac joint. Pathogenesis Although not comple...

Vertebral scalloping

Vertebral scalloping is a concavity to the posterior (or less commonly anterior) aspect of the vertebral body when viewed in a lateral projection. A small amount of concavity is normal, as is concavity of the anterior vertebral body (see vertebral body squaring). Posterior scalloping Causes of...

Vertebral vascular foramen

Vertebral vascular foramina are normal findings seen on cross-sectional imaging and should not be mistaken for a fracture, especially in the setting of trauma. They transmit: basivertebral veins (forms Hahn's canal): foramen is seen on the posterior surface of the vertebral body in the midline...

Vertebral venous plexus

The vertebral venous plexus is a highly anastomotic network of valveless veins running along the entire length of the vertebral column from the foramen magnum to the sacral hiatus. Gross anatomy The vertebral venous plexus is comprised of three interconnected divisions: internal vertebral ven...

Vertebra plana

Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...

Vertebroplasty

Vertebroplasty is an imaging-guided procedure which entails percutaneous injection of surgical polymethylmethacrylate (PMMA) cement into a diseased vertebral body. Vertebroplasty provides pain relief and strengthening of the bone of vertebrae weakened by disease. Indications It can be used as ...

Wedge fracture

Wedge fractures are hyperflexion injuries to the vertebral body resulting from axial loading. Most commonly affecting the anterior aspect, wedge fractures are considered a single-column (i.e. stable) fracture. Less commonly wedge fractures refer to a subtype of tibial plateau fractures. This a...

White matter

The white matter is the substance of the brain and spinal cord that contains the fiber tracts of neuronal axons in the central nervous system. The term is due to the paler color of the lipid-rich myelin that encase the axons in the tracts compared to the grey matter, which contains predominantly...

White matter tracts of the spinal cord

The spinal cord has numerous tracts of white matter that ascend and descend in the peripheral substance of the cord. They can be divided by their location and function: anterolateral columns anterior corticospinal tract medial longitudinal fasiculus spinothalamic tracts lateral spinothalami...

WHO classification of CNS tumors

The WHO classification of CNS tumors is the most widely accepted system for classifying CNS tumors and was based on the histological characteristics of the tumor. Although the most recent version of the 'blue book' is the 4th edition from 2007, an update has been released in 2016 3, which should...

Winking owl sign (spine)

The (absent) pedicle sign, also called the winking owl sign, occurs on plain film when a pedicle is absent. The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other open eye, and the spinous process to the beak of the animal on ...

Y sign (epidural lipomatosis)

The Y sign refers to a common appearance in lumbar epidural lipomatosis where excess fat in the extradural space compresses the dural sac into the shape of the letter "Y".

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