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Radiographic Procedures II Lumbar Spine, Sacrum, Coccyx & SI Joints Jena Heflin, MBA, RT(R) Lumbar Spine  Contains 5 lumbar vertebrae  Increase in size from 1st to 5th  Bears the weight of the spine inferiorly  Has a natural lordotic curve  Spinal cord terminates at L1-L2  Common site of back...

Radiographic Procedures II Lumbar Spine, Sacrum, Coccyx & SI Joints Jena Heflin, MBA, RT(R) Lumbar Spine  Contains 5 lumbar vertebrae  Increase in size from 1st to 5th  Bears the weight of the spine inferiorly  Has a natural lordotic curve  Spinal cord terminates at L1-L2  Common site of back injuries  The intervertebral disks are most commonly injured Anatomy of a Lumbar Vertebra  Body  Deeper anteriorly than posteriorly  Flattened  Transverse Process  Smaller  superior and inferior surfaces than those of the t-spine  L1-L3 are directed laterally  L4-L5 are directed slightly superiorly Pedicles  Strong and directed posteriorly Anatomy of a Lumbar Vertebra  Laminae  Thicker  than cervical or thoracic vertebrae Spinous Process  Large, thick, & blunt  Project posteriorly and horizontally  Mamillary Process  Smooth rounded projection on the back of each superior articular process  Accessory Process  Located process at the back of the root of the transverse Anatomy of a Lumbar Vertebra  Pars Interarticularis   Part of the lamina between the superior and inferior articular processes Unique characteristics of L5  Body is wedge-shaped for articulation with the sacrum  Intervertebral disk is also wedge-shaped  Shorter and smaller spinous process  Thickest transverse process Anatomy of a Lumbar Vertebra  Zygapophyseal Joints   Majority are demonstrated in a 45° oblique position Intervertebral Foramina  Situated at right angles (90°) to the MSP   Exception: L5, which is turned slightly anteriorly Majority are demonstrated in a true lateral position. Complete Figure 1 & 2 Anatomy of a Lumbar Vertebra Anatomy of a Lumbar Vertebra Sacrum  Formed by the fusion of 5 sacral vertebrae  Curved, triangular-shaped bone  Located between the iliac bones of the pelvis (SI Joint)  Female sacrum is more acutely curved  Results in a sharper angle at the junction of the lumbar and pelvic curves  Base = superior surface  Apex = inferior surface Sacrum  Sacral Promontory   Prominent ridge on the base of the sacrum Ala  Wing-like lateral mass on each side of sacral base  Contains articular surface for iliac bones of pelvis Sacrum   Sacral Canal  Located behind the bodies of the sacral segments  Continuation of the vertebral (spinal) canal  Transmits sacral nerves Sacral Foramina  Located on anterior and posterior walls of sacral canal  Passage for sacral nerves and blood vessels Sacrum  Apex has an oval facet for articulation with the coccyx  Sacral Cornua  Two processes projecting from the posterolateral aspect of the last sacral segment  Joins the coccygeal cornua Coccyx  Composed of 4 rudimentary vertebrae fused into one bone by adulthood  Diminishes in size from base to apex  Base = superior surface  Apex = inferior surface  Curves inferiorly and anteriorly  Coccygeal Cornua  Project superiorly from posterolateral aspect of the first coccygeal segment to join sacral cornua Anatomy of Sacrum/Coccyx Image Analysis Presentation of radiographs, pertinent anatomy, and positioning criteria General Considerations  40-inch SID  14 x 17 IRs for L-Spine  10 x 12 IR for L5-S1 spot  10 x 12 IRs for Sacrum, Coccyx, & SI Joints  Shield breasts and thyroid AP L-Spine  Patient supine  Bend pt.’s knees to bring spine closer to table  Decreases lordotic curve  CR  level of L4 (iliac crest)  Collimate to spine   Some protocols may require collimated to the skin Taken on expiration May be done PA to reduce patient dose AP L-Spine Structures Seen  Demonstrates lumbar bodies, transverse processes and intervertebral disks  Include T11 to distal sacrum  Open intervertebral joints  SI joints equidistant from spine 45° RPO/LPO L-SPINE  Roll patient up 45°  CR 2 inches medial to ASIS and 1½ inches above iliac crest (at level of bottom of the ribs)  Collimate to spine  Taken on expiration May be done RAO/LAO to reduce patient dose 45° RPO/LPO L-SPINE Structures Seen  Zygapophyseal joints of L1-L4 are seen on the down side  To demonstrate the zygapophyseal joint of L5-S1, pt. needs to be obliqued 60  Demonstrates “Scottie Dogs” RPO Scottie Dog Parts Superior Articular Process Ear Transverse Process Nose Pedicle Eye Pars Interarticularis Neck Lamina Body Inferior Articular Process Front Leg Left Lateral L-Spine  Patient in true lateral position  Hips, shoulders, and knees are on top each other, flex knees  Place hands in “praying position”  CR at iliac crest  If L-spine is not horizontal, angle CR 5-8 caudal so it is  with the spine  Use lead strip behind patient to reduce scatter  Taken on expiration Left Lateral L-Spine Structures Seen  Intervertebral foramina of L1-L4 are seen  Open intervertebral disk spaces  Spinous processes in profile  Some protocols may require the entire sacrum to be included L5-S1 Spot  Patient in same position as Left Lateral  Angle CR caudal:  5° - male  8° - female  CR is midway between iliac crest and level of ASIS (2 inches posterior to ASIS and 1.5 inches inferior to iliac crest)  Collimate down at least to 8x10  Taken on suspended respiration L5-S1 Spot Structures Seen  Lateral aspect of L5-S1  Open lumbosacral intervertebral joint  Some protocols may require the entire sacrum be included AP Axial L5-S1  Pt. supine on table with legs extended  Angle CR cephalic:  30° - male  35° - female  If PA, angle caudal  CR enters MSP, 1½ inches superior to pubic symphysis  Collimate down at least to 8x10  Taken on suspended respiration AP Axial L5-S1 Structures Seen  Lumbosacral junction and sacrum  Open intervertebral space between L5S1 AP/PA L-Spine Weight-Bearing  a.k.a. R/L Bending  Pt. standing in AP or PA position at upright bucky   Pt’s arms hang by the sides unsupported Have pt. lean directly lateral as far as possible without rotation and lifting the foot  Try to keep pelvis straight  CR  level of L3  1 radiograph taken with pt. bending toward the right, and the other taken with the pt. bending toward to left  Taken on suspended respiration AP/PA L-Spine Weight-Bearing Structures Seen  Demonstrates mobility of the intervertebral joints  Helpful in localizing joint movement of disk protrusion  No rotation of the patient in bending position Lateral Hyperflexion/Hyperextension  Pt. in left lateral recumbent position  Hyperflexion   Have pt. lean forward and draw the thighs up to flex the spine Hyperextension  Flexion Have pt. lean backward and posteriorly extent the thighs and limbs as much as possible (arch back)  CR  to L3 or level of spinal fusion  Take on suspended respiration  Annotate hyperflexion/ hyperextension Extension Lateral Hyperflexion/Hyperextension Performed to determine whether motion is present in the area of a spinal fusion or to localize a herniated disk Hyperflexion Flexion Extension Hyperextension AP Sacrum  Patient supine  Angle CR 15° cephalic  If performed PA, angle caudal  Collimate to at least 8x10  CR is midway between ASIS and pubic symphysis (2 inches inferior to ASIS)  Taken on suspended respiration AP Sacrum Structures Seen  Sacrum free of foreshortening with sacral curve straightened  Pubic bone not overlapping the sacrum  No rotation AP Coccyx  Patient supine  Angle CR 10° caudal  The tube angle corrects for the curvature  If performed PA, angle cephalic  Collimate to at least 8x10  CR is midway between ASIS and pubic symphysis (2 inches inferior to ASIS)  Taken on suspended respiration AP Coccyx Structures Seen  Anterior aspect of coccyx is seen  Coccygeal segments not superimposed Lateral Sacrum  Patient in true left lateral position  Interiliac plane  to the IR  CR  at the level of the ASIS, and 3½ inches posterior  Collimate to at least 8x10  May be combined to include the coccyx   If so, then open to 10x12 Taken on suspended respiration May have to utilize sponge to straighten out the Sacral area Lateral Sacrum Structures Seen  Lateral aspect of the sacrum (& coccyx if included)  Closely superimposed superior margins of the ischia and ilia Lateral Coccyx  Patient in true left lateral position  CR is 2 inches inferior and 3½ inches posterior to the ASIS  Collimate to at least 8x10  Taken on suspended respiration Lateral Coccyx Structures Seen  Lateral aspect of the coccyxsuperior margins of the ischia and ilia AP Axial SI Joints  Pt. supine on table with legs extended  Angle CR cephalic:  30° - male  35° - female  If PA, angle caudal  CR enters MSP, 1½ inches superior to pubic symphysis  Collimate down at least to 8x10  Taken on suspended respiration AP Axial SI Joints Structures Seen  Symmetric SI joints free of superimposition Include L5-S1 and entire sacrum RPO/LPO SI Joints  Pt. rotated into 25-30 RPO or LPO position  CR enters at level of ASIS, 1-inch medial to elevated side   You are imaging the upside SI joint Taken on suspended respiration RPO/LPO SI Joints Structures Seen  Open SI joint on upside demonstrates left SI joint Scoliosis Series  AP & Lateral views are performed of entire spine  Sometimes lateral is omitted to reduce pt. dose  AP demonstrates lateral curvatures  Lateral demonstrates anterior/posterior curves and  Methods 3 14x17 IRs are used in a scoliosis holder and the images are fused using the CR software  Scoliosis  board is used Refer to positioning notes for criteria What would you do? Critical Thinking Situation A radiograph of an LPO projection of the L-spine reveals that the downside pedicles and zygapophyseal joints are projected over the anterior portion of the vertebral bodies. What specific positioning error has occurred? Choice A Choice B The patient is under-rotated The patient is over-rotated Situation A patient comes to the radiology department for a routine lumbar spine series. She has severe kyphosis. How can the lumbar spine series be modified to accommodate this patient? Correct Answer: Situation A patient with an injury to the coccyx enters the emergency department and is unable to stand. When attempting to perform the AP projection, the patient complains that it is too uncomfortable to lie on his back. What can you do to complete this exam? Correct Answer: Assignment  See course schedule for reading assignment  Study Positioning Notes!!!  L-Spine Worksheet  Section 1: Exercise 5 – 9, 10 (Q. 22 – 25)  Section 2: Exercise 4 – 5