C Spine

Question 1

Routine C-spine X-rays

Answer 1

• AP Axial (15 degrees cephalad) for C3-C7
• Lateral (erect or HCR)
• Swimmer’s Lateral (5-10 degree Caudal)

Question 2

Special C-spine X-rays

Answer 2

• Cervical 45 degree Oblique
• Wagging Jaw AP: HCR (OmBL 0 degrees)
• Flexion and Extension

Question 3

Lateral C-spine

Answer 3

HCR lateral
dorsal patient
CP = C4 (center inferior and posterior to gonion)
SID = 150 -180 cm
IR 3-5cm above EAM
Respiration - Suspend on full expiration

Position:
C1 through C7 should be demonstrated.
If the junction of C7 to T1 is not demonstrated, additional images, such as the swimmer’s lateral method radiograph, should be obtained.
R & L zygapophyseal joints superimposed .
Bodies will be free of superimposition of articular pillars & spinous process will be seen in profile.

Have to get EAM and sternal notch
24 cm long and 16 cm wide

Question 4

How do you perform a swimmer’s lateral

Answer 4

IR similar to HCR lateral
elevate arm close to IR - depress opposite shoulder
- HCR, centered to C7-T1 (4 - CM superior to level of jugular notch).
- Trauma = Cone out to get C2 and downwards of T spine
- Pathology = cone tight

Note: 1 CR centred to grid to CR (prevents grid cutoff).

Note: 2 A 5° CR caudal angle may be required if patient cannot depress shoulder opposite IR.

Note: 3 Both the HCR Lateral & HCR Swimmer’s lateral can be performed with patient on trolley. Upright chest board bucky can be used

Question 5

What are the two ways you can visualise zygapophyseal joint spaces?

Answer 5

Zygapophyseal Joints–90° Lateral

Intervertebral Foramina–45° Oblique
R or L lateral

CR 15° cephalad–upside visualized
LPO–right foramina
RPO–left foramina

CR 15° caudad–downside visualized
LAO–left foramina
RAO–right foramina
(less thyroid dose).

Center spine to CR &; midline IR.
Place pt’s arms relaexed at side; if pt is recumbent, place arms to maintain position.
Rotate body & head 45°

Question 6

Why is the C-SP Oblique Important?

Answer 6

Neuralgia

Obliques show intervertebral foramina formed by inferior notch of pedicle of vertebrae above & superior notch of pedicle of vertebrae below.

osteoarthritis = in the uncovertebral articulations of lower C-Sp frequently produce pressure on the nerve-roots lying in intervertebral foramina.

Question 7

Neuralgia

Answer 7

: defined as an intense burning or stabbing pain caused by irritation of or damage to a nerve. Often feels as if it is shooting along the course of the affected nerve.

Question 8

Lateral Oblique C-spines

Answer 8

PREPARE THE ROOM
Cassette: 18x24 or 24x30 Regular IR portrait
Tube: 150cm SID FFD, 15º cephalad tube tilt (for AP oblique)
The inferior light should be just above the SCJ because of the cephalad angle.

Technique: 70 kVp, 12.5 mAs fine focal spot
Feet should be pointing to a corner of the room so that the patient is 45 degree obliqued. However, when a patient is fat, the patient isn’t obliqued as much. Look at the MCP to be 45 degrees. Pedicles in midline and the other pedicles at the anterior part of the body.

24 cm long and 16 cm wide

Question 9

When you have positioned for a lateral oblique xray correctly what should you see?

Answer 9

Correct rotation & CR angle, disk spaces & intervertebral foramina of interest (C2 - C7) should be open, & pedicles of interest should be seen in full profile.

Question 10

What happens if you over or underrotate an obl?

Answer 10

Overrotation or underrotation will narrow and partially obscure the intervertebral foramina.

Question 11

When do you know for sure you have overrotated for a obl?

Answer 11

On-end pedicles aligned at midline of C SP body & visualization of facet joints indicate over rotation. Pedicles are placed posteriorly.

Question 12

When do you know for sure you have underrotated for a obl?

Answer 12

Obscured intervertebral foramina & pedicles indicate underrotation.

Question 13

What are the different ways to cause a sustained c-spine injury?

Answer 13

flexion,
 compression/crush 
 extension
 rotation
 shearing

Question 14

Which type of fracture increases overall bone length?

Answer 14

distraction

Question 15

Why do kids get odontoid fx?

Answer 15

large head small spine

Question 16

Clay Shoveler’s fracture

Answer 16

This oblique or vertical fx of spinous process of C-6 or C-7 is caused by an acute powerful flexion

Question 17

Hangman’s Fracture

Answer 17

Hangman fracture (also known as traumatic spondylolisthesis of axis) is a fracture which involves the pars interarticularis of C2 on both sides, and is a result of hyperextension and distraction. C2 anteriorly partially dislocates on C3.

seen only in 25% of patients.

hyperextension, such as a high speed motor vehicle accident,

Question 18

Jefferson Fracture

Answer 18

Fracture(s) of the C1 ring.

Fx consists of unilateral or bilateral fractures of the anterior and posterior arches of C1. This is an unstable injury.

Question 19

Tear drop fracture

Answer 19

Avulsion fracture due to an anterior ligament pulling of the anterior part of a vertebral body

Question 20

What patient prep would you need to do for C-spine X-rays?

Answer 20

Hairclips, dentures (possibly), earrings, necklaces, pull down bra straps, hearing aids and possibly tie up hair.

Question 21

How do you position for a peg x-ray?

Answer 21

Sitting or supine.
Trauma = center next to nose and start angling cephalad a skinny slit from root of nose to EAM. Then using the same angle center inside mouth. Open up collimation.
Pathology = root of nose to EAM or OMBL 30 degrees. HCR inside of open mouth which is last. Check rotation

Question 22

What are the exposures and speed class for peg, lateral, swimmers, AP and oblique?

Answer 22

peg = 73 kVp 12 - 16 mAs, 400
Lateral = 73 kVp at 16 mAs, 400
Swimmers = 85 kVp at 80 -160 mAs (CR) and at 60 mAs (DR)
AP = 70 kVp at 8 - 10 mAs
Oblique = 73 kVp at 12.5 mAs

Question 23

Are C-spines done with or without grids?

Answer 23

With Grids because they are placed within the bucky

Question 24

Why do we increase SID in a lateral?

Answer 24

The SID increases from 100cm to 150cm because in a lateral the shoulders are in the way. So the increase in SID reduces magnification of spine.

Question 25

When you have a osteroporotic patient how do you alter the exposures?

Answer 25

Using the 15% rule, you reduce the kVp by 15% and double the mAs.

Question 26

How do you know you have a good exposure on your C-spines?

Answer 26

The contrast and density adequate to demonstrate bony structure, trabeculae pattern and bony sharp cortical outlines of each vertebra.