Cervical Spine Flashcards
Three view trauma series
- lateral c-spine = must inlcude T1
- AP
- odontoid peg view
Vertebral Alignment Lines
- anterior line: Anterior margins of the vertebral bodies
- posterior line: posterior margins of the vertebral bodies
- spinolaminar line: along the bases of the spinous processes (NOT THE POSTERIOR ASPECT OF THE SPINOUS PROCESS) - There may be a step at c2 but this shouldn’t be more than 2mm
C2 and Odontoid Peg
- (what is the coffee bean?)
- (distance between coffee bean and odontoid peg?)
- (what is Harris’ ring of c2?)
- Anterior line continues to the anterior aspect of the peg, posterior line continues to the posterior aspect of the peg
- on a lateral image, the anterior arch of C1 presents as an oval - COFFEE BEAN- the gap between the anterior arch of C1 and the peg should be 3mm of adults, 5mm for children
- Harris’ ring of c2 - white ring projected over the base of the peg - normal for inferior aspect of this ring to appear incomplete
Pre-Vertebral Soft Tissues
- C1-C4= 7mm wide
- C5-C7= 22mm wide
This line appears grey on the image
Normal Looking AP C Spine
- spinous processes are in a straight line
- distance between spinous processes should be equal - no greater than a 50% difference
- this may not be true if neck is held in felxion due to spasm
- some spinous processes are bifid - may appear as though it is not straight
Normal Peg View
- (lateral masses?)
- (how do you determine if malalignment is rotational?)
- lateral margins of C1 should align with lateral margins of C2 - no step in the line (rotation of the neck can affect this)
- lateral masses of C1 should be symmetrical
- the odontoid peg should be equidistant form the lateral masses
if lateral margins of C1 and C2 do not align, look at the lateral masses. If the distance is greater one one side, it is a rotational effect.
STEPS TO ASSESS LATERAL C-SPINE IMAGE
- is top of T1 seen? - if not swimmers should be done
- check the anterior, posterior and spinolaminar line
- check size and alignment of vertebral bodies
- check intervertebral disc spaces - widening?
- check prevertebral soft tissue line
STEPS TO ASSESS THE LONG AP VIEW
- are the spinous processes in line?
- are the tips of adjacent spinous processes equal? >50% is abnormal
STEPS TO ASSESS C1-C2 ARTICULATION
Lateral:
- # of odontoid peg?
- horizontal displacement of harris’ ring?
- distance between posterior aspect of C1 arch and the peg shouldn’t be more than 3mm
- prevertebral soft tissue swelling?
AP:
- # odontoid peg?
- displacement of C1 lateral masses?
Mach effect
Thin black line on the peg that is not a #
caused by superimposition of surrounding anatomy
NAME THE PATHOLOGY
vertical force caused # of C1 in several places
- on AP image: the space on each side of the peg is widened, lateral margins of c1 may over hang those of c2
Jefferson fracture
NAME:
General degeneration of the spine
spondylosis
AP C-spine positioning
- Patient AP, back against detector
- shoulders equidistant from detector to prevent rotation
- chin raised: lower margin of upper incisors with the base of the skull
- centre on midline at level of C4, 15deg caudal angle
- collimation: inculde T1, C2, as high as possible
- 70kVp 8mAs (AEC)
- Grid is used
Lateral C-spine Positioning
- Detector placed on patients left side
- Chin raised slightly so angle of mandile is not superimposing over C1C2
- centre at the midline at the level of C4
- collimate to include soft tissue of ear, T1 and anterior and posterior skin margins
- 66kVp 10mAs
- no grid is used due to air gap effect caused by shoulder distance
Odontoid Peg Positioning
- Patient back against the detector
- shoulders equidistant form the detector
- lower margin of upper incisors should be in line with the base of the skull
- patient opens mouth as wide as possible
- centre: in the centre of the mouth
- collimate to include upper and lower incisors and the lateral aspects of the mandible
- 70kVp 5mAs
- grid is used
