Ankylosis Spondylitis (AS) is probably the most well-known seronegative spondyloarthropathy and is certainly one of the most recognisable, with its characteristic “question mark” posture and reduced mobility in the spine.

It commonly affects men more than women and begins in late teenage years or early twenties, often beginning as a dull ache or stiffness in the lower back and sacro-iliac joints, worst on waking. It is a chronically inflammatory condition and Without treatment can steadily progress up the spine, fusing vertebral segments and causing chronic postural adaptations.

In clinic, alongside thorough case history taking, we typically have two specific tests for AS. Both measure movement in the body, one focussed on the lumbar spine and the other, the rib cage. Using a standard measuring tape we can assess:

• lumbar spine flexion – should be >5cm (see video below)
• rib expansion – should be >3cm

Once diagnosed, the BASDAI index can be used to measure progression and development of the disease.