Spondylitis. Spondylosis. Spondylolysis. Spondylolisthesis. They share the same root and nothing else.
One inflames. One ages. One fractures. One slips. By the end of this page you will never mix them up again.
spondylo · vertebra · the rest is the suffix
The Meme · Tap a Wizard
Which one are you?
Four bone wizards. All claim to be the spondylo. Three are lying. The exam stem will pretend any of them could be the answer.
Tap each wizard to see what they really are, and how to call their bluff.
they all point at each other · only one is the diagnosis
Tap any wizard above. One inflames. One ages. One fractures. One slips.
Decoder Grid
Translate the suffix, win the question
Every spondylo-word is the same root (vertebra) plus a suffix. The suffix is the entire diagnosis.
Learn these four endings and the four diseases stop being four.
-itis
inflammation
The vertebra is on fire. Immune cells are attacking the joint.
Hook: if the word ends in itis, somebody is mad. Bronchitis, dermatitis, arthritis. Same rule.
-osis
degeneration / wear
The vertebra got old. Cartilage thinned, bone spurs grew, things stiffened.
Hook: osis = old. Arthrosis, scoliosis, fibrosis. The body changed shape without inflammation.
-lysis
broken apart
A piece of vertebra cracked through. Specifically the pars interarticularis.
Hook: lysis = lysed = popped. Same word for hemolysis (red cells popping) and electrolysis (bonds breaking).
-listhesis
slippage
One vertebra slid forward off the one below it. The stack is no longer stacked.
Hook: listhesis sounds like list (a ship that lists is leaning over). The spine is listing forward.
Wizard 1 of 4 · itis
Spondylitis
Inflammation of vertebrae. The classic exam version is ankylosing spondylitis: a young man whose spine fuses up because his immune system will not stop attacking the joints.
The dead giveaway: 22-year-old man, low back pain that is worse in the morning and gets better with exercise, lasts more than 3 months. That is not a disc. That is inflammation.
Who
Young man, teens to 30s. Pain > 3 months.
Where it starts
Sacroiliac joints. Walks UP the spine over years.
Imaging hallmark
Bamboo spine on X-ray. Vertebrae fused into one column.
Outside the spine
Anterior uveitis (painful red eye), aortic regurg, restrictive lung disease.
Board pearl: AS is the head of the seronegative spondyloarthropathy family (psoriatic, reactive, IBD-associated). All HLA-B27 positive. All rheumatoid factor NEGATIVE. The lecture line: if back pain in a young man improves with movement, your move is HLA-B27 plus sacroiliac films, not an MRI of the lumbar discs.
healthy column with discs → ossified bamboo column
Wizard 2 of 4 · osis
Spondylosis
Degenerative arthritis of the spine. The wear-and-tear cousin of osteoarthritis, just applied to vertebrae. This is the most common cause of lumbar spinal stenosis in elderly patients.
The dead giveaway: 68-year-old with back pain that gets worse with standing and walking, better when leaning forward over a shopping cart (the shopping cart sign). That is stenosis from spondylosis.
Lumbar spinal stenosis → neurogenic claudication (leg pain with walking).
Discriminator
Forward flexion relieves it. Vascular claudication does NOT improve with bending forward.
Board pearl: Spondylosis is the silent disease everyone over 60 has on imaging. It only matters when it pinches a nerve or narrows the canal. Buys the shopping-cart sign and the neurogenic claudication question. See spinal stenosis deep dive for the full pinch.
Wizard 3 of 4 · lysis
Spondylolysis
Fracture of the pars interarticularis. The pars is the bony bridge connecting the upper and lower facets on each side of a vertebra. Repeated hyperextension cracks it.
Spondylolysis (Pars Fracture)Young athleteHyperextensionL5 most common
The dead giveaway: 15-year-old gymnast (or football lineman, or volleyball player) with focal low back pain that worsens with extension. Oblique lumbar X-ray shows the Scottie dog wearing a collar. The collar IS the fracture.
Repeated hyperextension → stress fracture of the pars.
Classic sign
Scottie dog with a collar on oblique X-ray. The collar = the pars defect.
When to worry
Bilateral pars fracture → the vertebra can slip → becomes spondylolisthesis.
Board pearl: The pars is a tiny strut, and the L5 pars takes the most strain because L5 sits on the angled sacrum. If a teenage athlete with extension-pattern pain gets an oblique X-ray, you are looking for a collar on the dog.
the collar around the dog’s neck IS the pars defect · that is the diagnosis
Wizard 4 of 4 · listhesis
Spondylolisthesis
One vertebra has slipped forward off the one below it. Most often L5 slides forward over S1. This frequently follows bilateral spondylolysis: both pars cracks → the vertebra loses its rear anchor and slides forward.
SpondylolisthesisL5-S1 most commonAnterolisthesisMeyerding I-V
The dead giveaway: Low back pain plus visible step-off on palpation of the lumbar spinous processes. Tight hamstrings on physical exam. Lateral X-ray shows one vertebra sitting forward of the one below it like a stacked book that slid out.
Most common cause
Bilateral spondylolysis (the rear bridges cracked, so the vertebra slid).
Most common site
L5 over S1.
Grade
Meyerding I-V by % slip. I = ≤25%. V = complete displacement (spondyloptosis).
Symptoms
Low back pain, hamstring tightness, sometimes radicular leg pain. Worse with extension.
Board pearl: Spondylolysis is the precursor; spondylolisthesis is the consequence. If a teenage athlete with hyperextension pain develops a palpable step-off, both pars probably cracked and L5 slipped on S1. Anterior slip = anterolisthesis (the common one). Posterior slip = retrolisthesis (rare).
L5 slid forward off S1 · the “step” is what you palpate
One-Look Comparison
The Quartet, side by side
If you only have 10 seconds before a board question, this is the table that wins it.
Term
What it is
Classic patient
Imaging tell
First move
Spondylitis
Inflammation of vertebrae (AS most common)
Young man, morning stiffness, sacroiliac pain > 3 mo
Bamboo spine, sacroiliitis
HLA-B27, NSAIDs, TNF blocker if severe
Spondylosis
Degenerative arthritis of spine
Over 60, pain worse standing, better leaning on cart
Same teen athlete with palpable step-off, tight hamstrings
Lateral X-ray: one vertebra sits forward of the next
Grade it (Meyerding I-V); brace low grade, surgery high grade
Quiz · 6 vignettes
Run the trap
Each stem looks like it could be any of the four. The suffix gives it away. Pick the right wizard.
Medically reviewed by Kaitlyn Cocuzzo, MD and Fatima Ali, DO · Last updated June 30, 2026 at 2:05 AM ET
Bone Wizardry is an independent educational resource for visual learning in the medical sciences. It is not affiliated with, endorsed by, or sponsored by any licensing or examination board, contains no real or recalled examination questions, and does not guarantee any educational or examination outcome.
