Ankylosing spondylitis


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Ankylosing spondylitis

Musculoskeletal system

Pediatric musculoskeletal conditions

Radial head subluxation (Nursemaid elbow)

Developmental dysplasia of the hip

Legg-Calve-Perthes disease

Slipped capital femoral epiphysis

Transient synovitis

Osgood-Schlatter disease (traction apophysitis)

Musculoskeletal injuries and trauma

Rotator cuff tear

Dislocated shoulder

Radial head subluxation (Nursemaid elbow)

Winged scapula

Thoracic outlet syndrome

Carpal tunnel syndrome

Ulnar claw

Erb-Duchenne palsy

Klumpke paralysis

Iliotibial band syndrome

Unhappy triad

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Patellofemoral pain syndrome

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Compartment syndrome


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Lordosis, kyphosis, and scoliosis

Joint disorders



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Juvenile idiopathic arthritis


Calcium pyrophosphate deposition disease (pseudogout)

Psoriatic arthritis

Ankylosing spondylitis

Reactive arthritis


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Muscular disorders

Muscular dystrophy



Inclusion body myopathy

Polymyalgia rheumatica



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Musculoskeletal system pathology review

Back pain: Pathology review

Rheumatoid arthritis and osteoarthritis: Pathology review

Seronegative and septic arthritis: Pathology review

Gout and pseudogout: Pathology review

Systemic lupus erythematosus (SLE): Pathology review

Scleroderma: Pathology review

Sjogren syndrome: Pathology review

Bone disorders: Pathology review

Bone tumors: Pathology review

Myalgias and myositis: Pathology review

Neuromuscular junction disorders: Pathology review

Muscular dystrophies and mitochondrial myopathies: Pathology review


Ankylosing spondylitis


0 / 12 complete

USMLE® Step 1 questions

0 / 3 complete

High Yield Notes

15 pages


Ankylosing spondylitis

of complete


USMLE® Step 1 style questions USMLE

of complete

A 35-year-old man comes to the emergency department for evaluation of right eye pain and redness. The pain started suddenly, and it is difficult for him to open the right eye in a well lit room. The patient has a history of chronic atraumatic low back pain for which he intermittently takes ibuprofen. Chart review reveals three similar episodes of eye pain requiring emergency department visits; however, the patient failed to follow up with an opthamologist. The patient’s right eye appears injected with associated photophobia.  X-ray of the patient's spine is shown below.  

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Laboratory analysis demonstrates a C-reactive protein level 26 mg/L (normal <10 mg/L). If left untreated, this patient is at risk of developing which of the following complications?  

External References

First Aid








Ankylosing spondylitis p. 479

HLA-B25 and p. 98

labs/findings p. 722

therapeutic antibodies for p. 120

TNF- αinhibitors for p. 501

External Links


Content Reviewers

Rishi Desai, MD, MPH


Harry Delaney, MBChB

Evan Debevec-McKenney

Tanner Marshall, MS

Ankylosing spondylitis can be broken down - Ankylosing means stiffening, spondylo- refers to the vertebra, and -itis refers to inflammation.

So ankylosing spondylitis is a chronic inflammatory disease that affects the vertebral joints and makes the spine really stiff, but can also cause inflammation in other parts of the body like the eyes and blood vessels.

Ankylosing spondylitis, also called Bechterew disease, is part of a group of diseases called seronegative spondyloarthropathies.

Spondyloarthropathies are all autoimmune diseases that affect the joints, and they’re seronegative, which refers to the fact that rheumatoid factor, which is an autoantibody, is not found in the blood.

Alright, so in the healthy adult, the vertebral column is made up of 33 bones.

From top to bottom, the first seven bones are the cervical vertebrae, the next twelve are the thoracic vertebra and the next five, are the lumbar vertebrae.

Below that is a bone called the sacrum, which is attached to the pelvic bone on either side, called the ilium, and where they meet is the sacroiliac joint.

Below the sacrum is a tiny bone called the coccyx or tailbone.

There are two types of joints between the vertebra.

Between each of the vertebral bodies is an intervertebral disc which is made of type I and type II collagen and has two parts, the annulus fibrosis, an outer fibrous ring, and the nucleus pulposus, an inner jelly-like substance.

This disc forms a joint between each vertebra, and it allows slight movement and acts as a shock absorber.


Ankylosing spondylitis (AS) is a form of arthritis that primarily affects the spine. This chronic condition can lead to fusion of the vertebrae, resulting in a rigid spine. AS can also affect the sacroiliac joints, peripheral joints, and digits, and in severe cases, it can lead to disability. Some of the symptoms seen in AS include back pain, postural abnormalities, buttock pain, and pain in the peripheral joints such as the hips, knees, and ankles.


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  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "The ramifications of HLA-B27" JRSM (2003)
  6. "The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection" Annals of the Rheumatic Diseases (2009)

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