Doença Discal

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Liga de Radiologia 
Doença Discal 
 
Fardon DF, Williams AL, Dohring EJ et-al. Lumbar disc 
nomenclature: version 2.0: Recommendations of the combined task 
forces of the North American Spine Society, the American Society 
of Spine Radiology and the American Society of Neuroradiology. 
Spine J. 2014;14 (11): . 
Disc extrusion 
• Disc extrusion is a type of intervertebral disc herniation and is 
distinguished from a disc protrusion in that it: 
 
• has a broader dome (B) than neck (A), 
• and/or 
 
• extends above or below the disc level (into the suprapedicular or 
infrapedicular zone) 
• It is associated with a defect in the annulus fibrosus which allows 
herniation of nucleus pulposus beyond the confines of the disc. 
 
• Extrusion can be in any axial direction and may migrate either 
superiorly or inferiorly. If the extrusion migrates but becomes 
separated from the rest of the herniation it is known as a 
intervertebral disc sequestration. 
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Disc protrusion 
• Disc protrusions are a type of disc herniation characterised by 
protrusion of disc content beyond the normal confines of the 
intervertebral disc. 
 
• A protrusion is distinguished from a disc bulge in that it involves 
less than 25% of the circumference of the disc. Conversely it is 
distinguished from a disc extrusion in that its base is wider than its 
'dome' and it does not extend above or below the disc level. 
 
• It may also be described in terms of its axial position, into central, 
subarticular, foraminal, extraforaminal or anterior locations. 
 
• Additionally the terms contained (outer annulus fibrosus laminae are 
intact) and non-contained (all laminae are deficient) are also 
sometimes used. 
Disc herniation 
• Disc herniation refers to displacement of intervertebral disc material beyond the normal confines of the disc, but 
involving less than 25% of the circumference (to distinguish it from a disc bulge. A herniation may contain nucleus 
pulposus, vertebral endplate cartilage, apophyseal bone/osteophyte and annulus fibrosus. 
 
• Herniations are further divided into: 
 
• protrusion (base wider than herniation) 
• extrusion (base narrower than herniation) 
• migration 
• sequestration 
• Herniations can further be classified as: 
 
• contained 
• with intact outer fibers of annulus fibrosus and posterior longitudinal ligament 
• with intact posterior longitudinal ligament alone 
• not contained 
• tear of outer fibers of annulus fibrosus and posterior longitudinal ligament 
• The distinction between a protrusion and an extrusion is made on the basis of the size of the neck versus the size of 
the 'dome' of the herniation as well as the relationship to the disc level. 
 
• A protrusion has a broader neck than 'dome' whereas an extrusion has a narrower neck than dome. Also, if a 
herniated disc extends above or beyond the vertebral endplates then it is par force an extrusion. 
Disc bulge 
• Disc bulge should not be confused with a disc herniation. 
 
• A bulge involves more than one quarter (25%) of the 
circumference of an intervertebral disc (greater than 90 
degrees) whereas a disc herniation involves less than 25% 
of the diameter of the disc (less than 90 degrees) 3. Because 
it is limited by the annulus fibrosus it does not extend above 
or below the attached margins of the disc. 
 
• Bulges are always gradual and broad and often involve the 
whole disc (circumferential bulge). It is responsible in part 
(along with vertebral endplate bowing) for the disc height 
loss that is seen with aging. 
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