radiology 3b

• the longer the arm, the more force is needed to hold the same wt
• so, if yr arm is outstretched and you're holding even a small wt, the paraspinal muscles have to create a lot of force to stabilize the spine, bc these muscles (erector spinae) have short moment arms
• the forces are transmitted to vertebral discs

• transverse abdominus
• with multifidus

L5-S1

location in an object where stress is concentrated, so the object is likely to fail there

• surgical fusion
• this results in acceleration of degenerative changes adjacent to the sites of fusion

• large bodies
• large facet joints and SPs
• neural foramina exit in coronal plane

divides bony in to dorsal/ventral sides

coronal

lamina

• sup/inf articular facets
• pars interarticularis (btwn the above 2 on one vert)

• neural foramen 
• pedicle

• 12th rib
• TPs

• it's part of the lamina
• btwn sup and inf articular facets
• weakest part of the lamina

• connects lamina of adjacent vertebrae
• in a lat view of the lumbar spine it's posterior of the spinal foramen

• concects the SPs along their bodies, not at their ends
• on a lat lumbar x-ray visible btwn SPs

it's dark, you can see it just post of the body of L5, it's a line ant to the cord

ant and a bit off center from the vertebral body

they're the lighter blobs posterolat to the SP

• endplate is the edge of the vertebral body
• neural foramen is the gap post to the body, ant to the SP

• the sup art facet is more lateral
• the sup vert's facets (it's inf art facets) are medial

if you can't see the vert body, just a darkish outline of it, and if you're simultaneously seeing the facets, then that shadow of the body is the intervertebral disc

neural foramen

it looks like it's between the TP and the lamina

• it'll be in a very posterior view, where you're only seeing the SPs
• the 12th ribs will appear as 2 SP-ish dots lat to T1

• nothing - it'll usually heal by itself
• BUT, when imaging is needed, go w MIR first
• x-rays "may be sufficient ofr the initial eval of the following red flags:" recent trauma, osteoporosis, age > 70

• recent significant trauma (or milder trauma if >50 y/o)
• unexpained wt loss
• unexplained fever
• immunosuppression (from a disease or drugs)
• history of cancer
• IV drug use
• prolonged use of corticosteroids or hx of osteoporosis
• age > 70
• focal neurologic deficit w progressive or disabling symptoms
• duration > 6 weeks

I'm not typing these. Just review them before exams

• AP
• lateral
• spot lumbosacral
• oblique
• flex/ext

it's the first 3

• best method: count from the top
• or look for 12thr rib on lat or AP - it ends by the 1st lumbar vert
• look for the L/S junction (meeting of the arc of the sacrum and arc of the curving lumbar spine)

it has a white cloud cutting through the post portion of the body

really

• eye = pedicle
• head/nose = TP
• neck = pars interarticularis
• ear = sup art facet
• front leg = inf art facet
• hindmost leg = SP
• other hind leg = inf art facet

• movement of one vert body with respect to another
• fracture thru pars interarticularis
• lysis can lead to listhesis
• DDD can result in spondylolistheis w/o spondylolysis -- this is associated w spinal canal stenosis

spondylolysis (spondylolisthesis is when there's movement of one vertebral body w respect to another)

• <25% dislocation - grade 1
• 50% - grade 2
• 100 % (the post of the upper vert body is at ant spot of inf vert body) - grade 4

• happens w DDD
• when body moves w/o a disc this creates a vacuum that sucks gas from nearby structures, creating a very dark line btwn bodies

• disc space narrowing
• hypertrophic changes or osteophytes
• endplate sclerosis
• vacuum disc phenomenon

fusion of SPs

• mostly a soft tissue process
• on x-ray, look for destruction of endplates (they'll be concave)
• get MRI w contrast! but can still see some findings on x-ray

get MRI or CT -usually don't need contrast w MRI if just assessing for cord compression

• MVI > 35 mph
• falls > 15 ft
• MVP w pedestrian thrown > 10 ft
• assault w depressed consciousness
• known cervical spin injury
• rigid spine disease

get CT first

thoracolumbar junction (stress riser)

• stable compression fx
• isolated SP and TP fx
• spondylolysis

• compression fractures - ant wedge or biconcave
• burst fx (axial load)
• chance fracture
• fracture-dislocations
• minor fractures (TP, SP, pars interarticularis)

• how much loss of ht?
• has there been a change in alignment?
• does the post wall of vert body look like it's encroaching on the spinal canal?

• mid and post columns intact
• nonoperative management
• stable if >40% loss of height, consider Burst or Chance fracture

• classic injury from lap seatbelt
• fulcum is ant to spine and results in distraction injury involving all 3 columns
• unstable

it's a horizontal fx thru the vertebra

• dextro: right
• levo: left
• apex: peak of curvature
• cobb angle: A line is drawn along the superior end plate of the superior end vertebra and a
• second line drawn along the inferior end plate of the inferior end vertebra. If
• the end plates are indistinct the line may be drawn through the pedicles. The
• angle between these two lines (or lines drawn perpendicular to them) is measured
• as the Cobb angle.

• more supported than lumbar spine
• smaller articular processes
• seperate articular facet for ribs (on lat/post body and lat TP)
• upper 4 are more like c-vert, lower 4 like L-verts, middle 4 are a combo

btwn T3 and T4, lower than the first 2 ribs

• diffuse idiopathic skeletal hyperostosis
• flowing ossification of the ant long lig
• the disc space is preserved
• usually asymptomatic save some loss of mobility which is protective against DDD

• one vert that comes up white (trabecular looks same as cancellous)
• could be: osteoblastic metastasis, lymphoma, Paget's disease, fluorosis, osteopetrosis

• inflam of the SI joint
• ankylosing spondylitis
• inflam bowel disease
• Reiter's disease
• rheumatoid
• psoriasis
• infection