Lumbar Spine, Sacrum, and Coccyx Anatomy Clinical exam (Summer 2019)
Sacrum (labeling):
- 4 sets of pelvic sacral foramina - 2 Ala (wings) - 2 superior articular processes - articulate with inferior articular processes of L5 - Sacral canal - Median sacral crest - Sacral horns - 2 auricular surfaces - forms SI joint with Ilium of the hip bone - Promontory - Base (body) inferior
What are the special instructions for the scoliosis series with stitching?
- Images must overlap - No CR angle - Performed erect if possible (with gonadal shielding) - Equal weight on both feet - Patient cannot move between AP & Lateral images
Scotty dog (labeling):
- Superior articular process - ear - Inferior articular process - front leg - Transverse process - nose - pedicle - eye - Pars interarticularis - neck
Coccyx (labeling):
- Transverse processes - Horns of coccyx - Apex - inferior - Base - superior
What are some general considerations for exams of the L-spine?
- Use grid - Use gonadal shielding on AP/Lateral L-spine on males (top of shield at symphysis pubis) - Large focal spot
What questions can you ask your patient when it comes to a L-spine exam?
- Women under 50 - is there any chance you could be pregnant? - Truama or non-trauma? Any pain: - area of pain - radiating down legs/numbness in legs or feet - Difficulty breathing - if you lay patient supine - Check for hearing aids, insulin pumps, and pain pumps
What is the protocol for Thoracumbar?
1) AP 2) Lateral
What is the JMCGH protocol for L-spine?
1) AP 2) Lateral 3) L5/S1 Spot
What is the protocol for the SI joints?
1) AP 2) RPO 3) LPO (for comparison)
What is the protocol for a scoliosis series?
1) AP - must include C1 to end of coccyx 2) Lateral - must include C1 to end of coccyx
What are the CR locations for the L-spine projections?
1) AP L-spine - 1 1/2" above iliac crest 2) Lateral L-spine - 1 1/2" above iliac crest to midcoronal plane 3) L5/S1 Spot - 1 1/2" inferior to iliac crest and 2" posterior to ASIS 4) Oblique L-spine - 2" above iliac crest and 2" medial from upside ASIS 5) Lateral flexion/extension - bottom of IR 2" below iliac crest 6) AP R/L bending - bottom of IR 2" below iliac crest 7) Thoracolumbar - vertebral area of interest 8) AP Sacrum/Coccyx - 2" inferior to ASIS or 2" superior to Symphysis pubis 9) Lateral sacrum/coccyx - 3-4" posterior to ASIS 10) AP Axial SI joints - midsaggital plane and 2" below ASIS 11) Oblique SI joints - 1" medial to upside ASIS
L-spine technical factors:
1) AP L-spine - 80 kV @ 25 mAs 2) Lateral L-spine - 90 kV @ 32 mAs 3) L5/S1 Spot - 100 kV @ 32 mAs 4) AP Coccyx - 76 kV @ 16 mAs 5) AP Sacrum - 80 kV @ 25 mAs 6) Lateral Sacrum/Coccyx - 86 kV @ 40 mAs
What is the protocol for Sacrum/Coccyx?
1) AP Sacrum 2) AP Coccyx 3) Lateral Sacrum/Coccyx
What are the three projections performed on a scoliosis series with stitching?
1) AP/PA & Lateral C-spine 2) AP/PA & Lateral T-spine 3) AP/PA & Lateral L-spine
What are the two main considerations for Spine trauma patients (C-spine and/or backboard)?
1) Always keep spine stable 2) Perform laterals with horizontal beam
What anatomy does a normal vertebra consist of?
1) Body 2) Vertebral arch: - vertebral foramen (contains Spinal cord) - 2 pedicles - 2 transverse processes - 2 lamina - spinous process - 2 superior articular processes - 2 inferior articular processes - articular facets
What views are considered additional and are not part of the regular protocol for the L-spine?
1) Both obliques 2) Flexion and Extension 3) Right and Left Bending
What purposes does the vertebral column (spine/spinal column serve)?
1) Flexibility 2) Support 3) Transmits weight
What rooms are equipped with stitching software at the hospital?
1) IC 2) Room J 3) PA X-ray room S
What are the three types of abnormal curvatures of the spine?
1) Lordosis - abnormal inward curvature (swayback) 2) Kyphosis - abnormal outward curvature (hunchback) 3) Scoliosis - abnormal lateral curvature
How many degrees of CR angle is required for the AP coccyx?
10 degrees caudad to elongate coccyx
What size IR shod you use for the SI joints and the Sacrum/Coccyx?
10 x 12
How many thoracic vertebrae are there?
12 (T1-T12)
What size IR should you use for the L-spine, scoliosis- and thoracolumbar exams?
14 x 17
How many degrees of CR angle is required for the AP Sacrum?
15 degrees cephalad to elongate sacrum
What is the degree of patient obliquity needed for the oblique projection of the SI joints?
25-30 degrees of body and pelvis - provide support
How many degrees of a CR angle is required for the AP SI joints?
30-35 degree cephalic angle; 30 degrees for males and 35 for females
What is the min SID for exams of the L-spine?
40" (but 72" for Scoliosis exams)
How many degrees of rotation of the patient is required for the Oblique L-spine projection?
45 degrees; need equal rotation of shoulders and pelvis (roll pt. like a log) support with sponge
How many lumbar vertebrae are there?
5 (L1-L5); can occasionally have 6 vertebrae
How many sacral vertebral segments are there?
5 segments fused into 1 bone
What is the degree of CR angle for the L5-S1 Spot projection?
5-8 caudal angle if waist is sagging (5 - males/8 - females); places CR parallel to interiliac plane
How many sections of the spinal column are there?
5; cervical, thoracic, lumbar, sacrum, and coccyx
How many cervical vertebrae are there?
7 (C1-C7)
What is Spina bifida?
A birth defect in which a developing baby's spinal cord fails to develop posteriorly properly
What is HNP (herniated nucleus pulposus)?
A slipped disk along the spinal cord; The condition occurs when all or part of the soft center of a spinal disk is forced through a weakened part of the disk
What is the CR for the AP Axial L5/S1 projection?
ASIS and midsagittal plane
What radiopaque objects can possibly interfere with an examination of the L-spine?
Coats, bra, pants, sweat pants (metal around drawstrings), objects in pockets, underwear with metal snaps or sequins
If a right lateral L-spine is performed instead of a left lateral, what must you do?
Document this in RIS
T/F: You SHOULD tightly collimate on sides during scoliosis exams.
False; this may result is some of the spine being cut off
What is sciatica?
Irritated sciatic nerve - irritation by muscle pinch (piriformis syndrome) or a ruptured disc
What is a zygapophyseal joint?
Joint formed between the inferior and superior articular processes on either side on the vertebral body; Diarthrodial - Gliding
What are the two types of metastatic lesions?
Osteoblastic (proliferative) & Osteolytic (lesions with irregular borders)
What is housed within the spinal canal?
Spinal cord and CSF
How should you position the patient for an AP projection of the L-spine?
Supine if possible, have the patient flex their knees and hips (for comfort/reduces natural curve of the spine)
T/F: For the oblique SI joint projection you should bend the upside knee.
True
T/F: A Scoliosis series should be performed erect if possible, with convex side against the board.
True; demonstrates extent of lateral curvaturate
T/F: With careful positioning, you can shield males on L-spine projections.
True; females however are virtually impossible to shield due to the orientation of their anatomy
What zygapophyseal joint does a LAO L-spine demonstrate?
Upside (right) - marked right on the right side
How is the compensatory curve of the lumbar vertebrae formed?
When a child begins walking
What can you add to an oblique projection of the SI joints in order to better open the distal portion of the SI joints?
add 15-20 degree cephalic angle
What is spondylolisthesis?
anterior displacement of a vertebra or the vertebral column in relation to the vertebrae below; Occurs at any age, causing aching back and posterior thigh that increases with activity or bending
What section(s) of the vertebral column contain compensatory/concave (lordotic/inward) curvature?
cervical & lumbar
How many coccyx vertebral segments are there?
coccyx (tailbone) contains 3-5 but 4 (average)
What is spondylolysis?
defect in pars interarticularis/arch of the vertebra; usually in L5. can occur in lumbar or thoracic regions, though.
What joint does a LAO SI projection demonstrate?
downside (left) - mark left on left side
What zygapophyseal joint does a LPO L-spine demonstrate?
downside (left) - mark left on the left side
What joint does a RAO SI projection demonstrate?
downside (right) - mark right on right side
What zygapophyseal joint does a RPO L-spine demonstrate?
downside (right) - mark right on the right side
Why is the PA projection preferred for the scoliosis series?
due to less dosage to the breast and thyroid
What should the patient do before exams of the sacrum/coccyx in order to better visualize the anatomy?
empty bladder before exam - fecal material and gas can obscure anatomy
What are the intervertebral disks?
fibrous pads located between the vertebral bodies; serves as a shock absorber - consists of inner part (nucleus pulposus) & outer part (annulus fibrous)
Which direction should the scotty dog on an oblique projection of the L-spine always face?
head towards the marker
What is a compression fx?
is a collapse of a vertebra, it may be due to trauma or due to a weakening of the vertebra
What should you place behind the collimate area on the table top during the lateral/L5-S1 L-spine projections?
lead shield to reduce scatter
If an exam is ordered to correlate with a bone scan, what should you do before letting the patient leave?
make sure that Nuc Med is finished with the patient and the patient is free to leave
What is the CR angle for the AP Axial L5/S1 projection?
males - 30 degrees cephalad females - 35 degrees cephalad *performed as extra upon request or if needed
Which sex has a more anteriorly curved coccyx?
males; curved less on females due to birth canal
What are the breathing instructions for exams of the L-spine?
on expiration (hold breath)
How are the intervertebral foramina of the L-spine visualized?
on lateral projections
How are the zygapophyseal joints of the L-spine visualized?
on oblique projections
What should you place underneath a patient's waist if sagging is present for the L5-S1 Spot projection?
sponge
What 2 anatomical features form the intervertebral foramina?
superior (top half) and inferior (bottom half) vertebral notches
What is an intervertebral joint?
the joints located between the vertebral bodies; Cartilaginous - Amphiarthrodial
What section(s) of the vertebral column contain primary/convex (outward) curvature?
thoracic & sacral; these curves are formed soon after birth
How should you orient lateral images of the spine?
turn the images to the left
What joint does a RPO SI projection demonstrate?
upside (left) - mark left on left side of patient
What zygapophyseal joint does a RAO L-spine demonstrate?
upside (left) - marked left on the left side
What joint does a LPO SI projection demonstrate?
upside (right) - mark right on right side of patient
How should you have the patient bend for the lateral flexion/extension?
using their pelvis as a fulcrum (do not bend at hip joints); ensure no rotation
What is the singular form of the term for spinal bodies?
vertebra
What is the plural form of the term for spinal bodies?
vertebrae
How is the compensatory curve of the cervical vertebrae formed?
when a child raises their head and sits up
Scoliosis series; if spine has lateral curvature/deformity, how should you position the patient?
with the curved/convex side close to IR to open up joint spaces