Exam 3 - Positioning of C, T, L spine PDF

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All material for Exam 3
Beasley - Sp 2020
Positioning of C-spine, L-spine, T-spine...

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Positioning of the C- Spine 

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Routine projection o AP axial o Open Mouth – odontoid o Lateral  Flexion  Extension o Axial Obliques Emergency room patients or trauma patients, always perform cross-table lateral projection before proceeding with rest of routine exam Cervical collar is not to be removed for the cross-table lateral o We do not remove c-collars Remove any metallic objects from shoulders up and dentures

AP axial Projection      

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8x10 or 10x12 LW, 40 SID, 85-95kvp, grid Patient supine or erect, MSP centered to grid Chin elevated so that the occlusal plane (lips) is perpendicular to the IR (will be in same plane as mastoid tip) CR 15-20 degrees cephalic; entering C-4 at MSP o Light down to manubrium notch Shield pelvis, breasts on females SS: lower 5 C vertebrae, upper 2-3 T vertebrae, interpediculate spaces, intervertebral disk spaces, superimposed transverse processes, articular processes, presence or absence of cervical ribs EC: spinous processes at MSP, open intervertebral disc spaces, mandible and occipital bone superimposed the atlas and most of the axis, C3 to T2 and surrounding soft tissue

AP Projection – Open mouth         

Shows C1 and C2 8x10 or 10x12 LW, 40 SID, 85-95kvp, grid (must collimate to mouth) Patient is supine MSP centered to IR, or erect Open mouth and say “ah” Line from upper occlusal plane to mastoid tip is perpendicular to IR CR perpendicular to midpoint of open mouth Wagging Jaw – by moving the mandible to blur it from superimposing C1-C2 SS: AP projection of atlas and axis through the open mouth EC: dens, atlas, axis, articulations between axis and atlas; entire articular surfaces of C1-C2, superimposed occlusal plain of upper central incisors and base of skull, wide open mouth, mandibular rami equidistance from dens

Fuchs      

For odontoid process, performed when open mouth does not show odontoid 8x10 or 10x12 LW, 40 SID, 85-95kvp, grid Patient supine or erect Extend chin until tip of chin and mastoid process are vertical (MML perpendicular) CR directed perpendicular to IR entering just distal to the chin o May require a small angle cephalic SS: dens lying within the circular foramen magnum

Lateral            

8x10 or 10x12 LW, 60-72 SID, 85-100 kvp, grid Left or right, typically do left Patient erect or sitting in a lateral Chin raised, head in true lateral Center coronal plane through mastoid tips Patient holding sandbags Measure neck to neck, for skin dose measure neck to IR CR perpendicular to C-4; top of IR about 1 inch above EAM Respiration: end of expiration to depress shoulder SS: lateral projection of C spine bodies and interspaces, the lower five zygapophyseal joints, the spinous processes, articular pillars EC: demonstrate all 7 vertebrae & upper third of the body of T1, mandible does not overlap C1C2, no rotation, spinous processes in profile; C4 in enter, bone and soft tissue detail Do not pull down on patient shoulders for trauma

Alignment Assessment – assess four parallel lines 1. Anterior vertebral line (anterior margin of vertebral bodies) 2. Posterior vertebral line (posterior margin of vertebral bodies) 3. Spinolaminar line (posterior margin of spinal canal) 4. Posterior spinous line (tips of the spinous processes) Flexion & extension lateral        

10 x 12 LW IR; 60-72” SID, grid/non-grid, 85-100kvp Patient in true lateral position Demonstrates function of C-spine Perform after c-spine pathology of fracture has been ruled out CR perpendicular to C4, top of IR 2” above the EAM Collimate and shield SS: motility of C-spine; intervertebral disk spaces & zygapophyseal joints EC: hyperflexion: mandible almost vertical; all 7 spinous processes o Hyperextension: body of mandible almost horizontal; all 7 vertebrae in lateral position

Soft tissue neck

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8x10 LW IR, 6072” SID, 75-85 kvp (cut back) , grid Demonstrates soft tissue structures of the neck (pharynx and larynx) Center higher and anterior to include o Nasopharynx, oropharynx, laryngopharynx CR perpendicular to IR, centering IR o 1” below the level of EAMs to show nasopharynx o At gonions to show oropharynx o At level of laryngeal prominence to show larynx, laryngeal Coronal plane will be just anterior to TMJ Exposure made on inspiration to fill passages with air SS: soft tissue density of the pharyngolaryngeal structures EC: demonstrates ss; area from nasopharynx to uppermost part of lungs in preliminary studies o No superimposition of trachea by shoulders, no rotation, throat filled with air on preliminary studies

AP Axial Oblique (RPO/LPO)        

8x10 or 10x12 LW, 60-70”SID, 40” on table, 85-95 kvp, grid Patient oblique 45 degrees due to intervertebral foramina lie at 45 degrees from MSP o Because C-spine intervertebral foramina lie at 45 degrees from MSP Head is parallel to IR Chin is elevated CR 15-20 degrees cephalic entering at C-4 Mark side down SS: intervertebral foramina & pedicles farthest from the IR EC: C1-C7 & T1, PB markers on side down, intervertebral foramina open, open intervertebral disk spaces, and mandible does not superimpose C-spine o LATERAL SHOWS ZYGAPOPHYSEAL JOINTS o OBLIQUES SHOW INTERVERTREBRAL FORAMINA

PA Axial Obliques (RAO/LAO)         

8x10 or 10x12 LW, 60-70”SID, 40” on table, 85-95 kvp, grid Patient may be erect or recumbent, easier to do erect Head parallel to IR From lateral position rotate entire body into 45 degree oblique Elevate chin and center c-spine to midline of upright bucky or table CR 15-20 degrees caudal to C-4 Midpoint of IR coincides with CR SS: intervertebral foramina closest ot IR EC: open intervertebral foramina closest to IR, C1-C7 & T1, elevated chin so gonion does not superimpose C1/C2 ; open disk spaces

Trauma C-Spine 

AP and Laterals

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o Taken with collar in place Odontoid o Without movement, angle CR according to flexion of head Obliques o IR LW, placed on the side opposite the intervertebral foramina of interest, CR 15 cephalic and 5 degrees medial to enter the side of interest

Routine T- Spine    

AP Lateral Swimmer’s – twinning method Obliques

AP Projection           

14x17 LW, collimate to 7x17, 40” SID 85-95 kvp, grid Erect of recumbant Table or upright bucky Patient is in supine position, MSP centered to midline of table Flex knees and hips to reduce dorsal kyphosis, place thinnest portion under the anode because the anode heel effect, or filters can be used. Center transversely to the level of T7 (3-4“ distal to the suprasternal notch) The top of the IR is 1.5 – 2” above the shoulders CR perpendicular entering T7; approximately ½ way between the jugular notch and xiphoid process Breathing: exposure made of expiration to give more uniform density or breathing technique SS: thoracic bodies, intervertebral disk spaces, transverse processes, costovertebral articulation and surrounding structures, get last rib EC: all 12 vertebrae, uniform brightness, collimation, no rotation o * Use anode heel effect to get uniform density*

Lateral     

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14x17 LW, collimate to 7x17, 40” SID 85-100kvp (non-breathing), 75-85kvp (breathing), grid Erect or recumbant/Table or upright bucky Patient in lateral position (left lat. to place the heart closer to the film to reduce heart shadow) Center posterior half of thorax to midline of grid & Flex knees and hips for patient comfort Raise lower thoracic spine so it is parallel to the plane of the table. This is the preferred method o (roll a towel of sheet under waist) o If spine is not parallel to the table, the CR is directed:  Male – 15 degrees cephalic  Females – 10 degrees cephalic CR is perpendicular to enter level of T7 Breathing – suspend respiration (exposure made at end of expiration) Breathing – breathing technique (preformed to obliterate of blur out vascular markings and ribs as the patient breaths normally) Use 3-4 second exposure with low mA Use lead shield placed posterior to the spine, reduces scatter radiation reaching the IR SS: thoracic bodies, interspaces, spinous processes, intervertebral foramina, o If upper thoracic area is not demonstrated, do a Swimmers EC: thoracic vertebrae seen through rib and lung shadows, all 12 vertebrae, no rotation, open intervertebral disk spaces, collimation

Lateral Projection; Swimmer’s Technique

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Used to demonstrate cervicothoracic region when the shoulders superimpose C7 on the lateral C-spine & to demonstrate the upper thoracic vertebrae on T-spine 10x12 IR 40 SID on table or 72 SID if x-table or upright, 85-100kvp Dependent arm is extended above head and independent arm is along side o Depress forward/up shoulder and roll is back slightly CR perpendicular to C7-T1 interspace or 5 degrees caudal through C7-T1 SS: lower cervical/upper thoracic vertebrae EC: demonstrates from C5-T4, no rotation, shoulders separated

Oblique – Zygapophyseal joints        

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14x17 IR LW, collimate to 7x17”, 85-95 kvp, 40SID Erect or recumbent, in table or upright bucky The body is oblique 70-75 degrees from the IR The coronal plane is 70 degrees from horizontal Enter anterior obliques (RAO/LAO or posterior obliques (LPO/RPO) can be done CR is directed perp to T7. The top of the IR 1.5” above the shoulders Breathing – the exposure is made on suspended expiration respiration SS: zygapophyseal joints o RPO/LPO demonstrates the joints farthest from the IR o RAO/LAO demonstrates the joints closest to IR EC: all 12 vertebrae and zygapophyseal joints

L-Spine Positioning 

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Routine: o AP or PA o Lateral o Lateral spot (L5-S1) o Obliques Desirable to have intestinal tract free of as and fecal material, and also the urinary bladder empty PA vs AP o Pa reduces skin dose (20-30%) on females where ovaries are located o Prone places the L-spine with its natural curve with the intervertebral disc spaces parallel to the divergence of the beam o Opens up disc space o NOTE: always observe departmental policy AP/PA projection o 14x17LW or 11x14 LW, 40SID, 85-95kvp, grid o Patient maybe examined in erect or recumbent position o Use gonadal shielding if it is part of the protocol of the CES o The prone position presents he concave side of the lordotic curve to the x-ray tube, placing the intervertebral disk spaces parallel with the divergence of the x-ray beam o It is also mort comfortable for the emaciated patient or one in pain o Does not increase OID noticeable except with patients who have large abdomen o If Patient supine, Flex hips and knees to reduce lordotic curvature of lumbar spine o Center IR to level of iliac crests-L4 (14x17 = L4)(11x14 = L3/1.5” above iliac crest) o CR directed perpendicular o Suspend respiration at the end of expiration o SS: lumbar bodies, intervertebral bodies, intervertebral disk spaces, interpediculate spaces, lamina, spinous and transverse processes o EC: collimation, lower thoracic vertebrae to sacrum, collimate to lateral margin of psoas muscle, no artifacts across abdomen, no rotation, symmetric vertebrae, spinous process centered, SI joints equidistant from vertebral column, open disk spaces, bony trabecular detail Lateral Projection o 14x17 or 11x14 LW, 40SID, 85-100 kvp, grid o Patient may be erect or recumbent o Recumbant - patient lies on affected side in true lateral  Long axis of bodies of L-spine lie in mid coronal plane  Flex hips and knees for comfort, check for no rotation  Unless CR angulation is used, place a support under lower thorax so that long axis of spine is horizontal o Erect –  o CR perpendicular to crest (14x17) or 1.5” above crest (11x14)

If no support under lower thorax CR is angled  5 degrees caudal for males  8 degrees caudal for females o Suspend respiration o Ss: lateral projection of lumbar bodies, intervertebral disk spaces, spinous process, lumbosacral junction, sacrum & coccyx, profile image of lumbar intervertebral foramen (1-4; last one is oblique  NOTE: to improve rad quality place sheet of lead behind patient to absorb scatter from patient, especially for ACE. If not using AEC, may result in underexposed image due to scatter reaching sensor o EC: collimation, lower thoracic vertebrae to coccyx for lumbosacral spine procedure, area from lower thoracic vertebrae to proximal sacrum for lumbar only, vertebrae aligned down middle of image, no rotation, open intervertebral disk spaces and intervertebral foramina, bony trabecular detail and surrounding soft tissues Lateral Lumbosacral Junction L5-S1 o 8 x 10 LW; grid; 40" SID; 100-110 kVp o Patient may be erect or recumbent o Patient in true lateral on affected side o Flex knees for comfort; adjust spine to horizontal position; arms up by head o CR directed :  when spine is parallel CR is perpendicular entering 1 ½” inferior to iliac crest and 2” posterior to the ASIS  when spine is not parallel to IR, CR is 5 degrees caudal for males and 8 degrees caudal for females o Suspend respiration o SS: lateral projection of the lumbosacral junction, lower one or two lumbar vertebrae and upper sacrum o EC: open lumbosacral intervertebral joint, collimation that includes all L-5 and upper sacrum, crests of ilia closely superimposing each other when beam is not angled, right lateral or erect positions may open the lumbosacral joint Oblique projections (AP & PA) – lumbar zygapophyseal joints o Articular processes of the lumbar spine form angle of 45 degrees with the MSP, o An oblique the body 60°from plane of IR may be needed to demonstrate L5-S1 zygapophyseal joint o Angulation varies between patients and also side to side of one patient o Lumbar articular surfaces form chevron (opposite of T spine) PA obliques (RAO/LAO) o 14x17, 11x14 LW, 40 SID, 85-95 kvp, grid o Patient may be erect or recumbent o Patient semiprone supported by forearm and flexed knee; adjust body rotation to be 45 degrees o Center a sagittal plane passing 2 inches from the midline of the patient toward the elevated side o

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Center IR to level of L3 (midway between crest and inferior rib margin) CR directed perpendicular to L3 entering elevated side 2” lateral to palpable spinous process o Suspend respiration at end of exhalation o SS: zygapophyseal joints farthest from IR (side up) AP Oblique projections (RPO/LPO) o 14x17, 11x14 LW, 40 SID, 85-95 kvp, grid o Patient may be erect or recumbent o Patient rotates from supine to 45 degree obliquity o Center sagittal plane passing 2” toward the elevated side (2” lateral to spinous processes) from midline (or three fingers medial from ASIS) o Center IR to level of L3 o CR directed perpendicular to midpoint of IR o Suspend respiration o SS: zygapophyseal joints closest to Film o EC: collimation, area from lower thoracic intervertebral disk spaces to all the sacrum, no rotation on patient in bending position, bending direction correctly identified on the image with appropriate lead markers, bony trabecular detail and surrounding soft tissues L5-S1 Lumbar Zygapophyseal joints (AP/PA oblique) o An oblique the body 60°from plane of IR may be needed to demonstrate L5-S1 zygapophyseal joint o Angulation varies between patients and also side to side of one patient Spina fusion AP projection R or L bending o 10x12 or 14x17 IR, 85-95 kvp, 40 SID< grid o Patient supine or upright o 1st exposure: maximum bending to the right (left leg crossed over right) o 2nd exposure: maximum bending to the left (right leg crossed over left) o Shield o Suspend respiration o CR perpendicular to L3 o SS: AP projection of lumbar vertebrae with maximum left and right lateral flexion, used in patient with early scoliosis to determine structural change, also used to localized herniated disk shown by limited motion, demonstrates motion in area of a spinal fusion Hyperflexion/Hyperextension R/L o 14x17 LW, 40 SID, 85-100 kvp, grid o Latera recumbent or upright o 1st radiograph: Hyperflexion o 2nd radiograph: Hyperextension o Suspend Respiration o Shield o CR perpendicular to L3 o SS: o o

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