x-ray anatomy cervical spine

Question 1

what 3 anatomical lines should be traced for assessment of cervical injury

Answer 1

• along anterior vertebral body cortex
• along posterior vertebral body cortex
• along spinolaminar junction

Question 2

what is the average soft tissue width found anterior to the cervical spine

Answer 2

c1-c4= 4-7mm

c5-c7= 16-20mm

Question 3

assess the HARRIS RING at base of c2 (in lateral view), should be unbroken anteriorly, posteriorly and superiorly

Question 4

mind that in kids, it is a normal variant for ‘pseudosubluxation’, what is this and where is it found

Answer 4

• posterior movement/step found between c2/3 but no more than 2mm
• this is due to laxity of ligaments

Question 5

describe some things you can do to assess if there is injury in cervical spine

Answer 5

• assess superior/inferior endplates and posterior elements
• spinous process in straight like unless bifid
• equal distance b/w spinous process (no one should be 50% wider than the one above or below it)

Question 6

what is a Jeffersons fracture and how is this radiographically seen

Answer 6

• burst fracture of C1 (atlas), snap in 2 places of the ring structure of C1
• comminuted fracture, bilateral disruption of anterior and posterior arch + lateral displacement of both
• lateral masses (facet) of C1 can be seen overhanging odontoid peg (of c2) OR unilateral space widening of peg joint space in open mouth view

Question 7

there should be symmetric space b/w odontoid peg and lateral masses of c1 but normal asymmetric widening can be seen due to rotation of patients head

Question 8

what is a mach effect as seen in open mouth projection

Answer 8

artefacts e.g incisors or soft tissue overly base of peg and mimic fracture

Question 9

what is a neural arch fracture

Answer 9

longitudinal fracture through posterior neural arch (one fracture at the back of the arch of C1)

• caused by hyper-extension

Question 10

how can you identify an odontoid peg fracture besides the obvious fracture seen on open mouth view

Answer 10

• anterior soft tissue swelling
• disrupted Harris ring structure on base of C2 in lateral view

Question 11

what is a hangman’s fracture

Answer 11

• bilateral fracture of the pars interarticularis of C2
• traumatic spondylolisthesis (breaks and displaces/slips forward)
• due to hyperextension

Question 12

what is a uni/bilateral locked facet and its radiographic sightings

Answer 12

• vertebral body is anteriorly displaced by 25/50% and facets become disarticulated
• assess anterior and posterior vertebral lines for continuity

Question 13

what is a teardrop extension fracture

Answer 13

forced extension of the neck with resulting avulsion of the anteroinferior corner of the vertebral body

Question 14

how can you identify whiplash on xray

Answer 14

abnormal straightening of cervical spine, reversal of the normal cervical lordosis

Question 15

congenital fusion is a normal variant, especially in c2/c3 this can have what affect?

Answer 15

the odontoid peg is too short/cannot reach through the arch of C1 (also known as odontoid hypoplasia)

• fixed with hypoplastic odontoid peg