Posture Assessment and Correction
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Direct answer
Drop a plumb line from the earlobe and, in ideal standing alignment viewed from the side, it should pass roughly through the shoulder, the greater trochanter, just in front of the knee and onto the lateral malleolus. Assessment inspects anterior, posterior and lateral views for symmetry, spinal curves and muscle contour, then tests whether a deviation is flexible (functional) or fixed (structural). Correction pairs stretching of tight, short muscles with strengthening of their inhibited opponents — the logic of Janda's crossed syndromes — rather than simply instructing the patient to sit straight.
What you must remember
- Normal spinal profile: cervical and lumbar lordosis, thoracic and sacral kyphosis; typical thoracic kyphosis measures 20–45 degrees and lumbar lordosis 40–60 degrees on radiographs.
- Scoliosis is lateral curvature with vertebral rotation; it is diagnosed only at Cobb angle 10 degrees or more, and adolescent idiopathic scoliosis — right thoracic convexity, girls at higher risk of progression — is the commonest form.
- Screening: the Adams forward bend test exposes the rib hump (prominence on the convex side); a scoliometer reading of about 5–7 degrees or more warrants radiographic referral.
- Management bands: curves 10–25 degrees observed with specific exercise, 25–45 degrees braced (Boston or Milwaukee), beyond about 45–50 degrees considered for surgery.
- Upper crossed syndrome: tight pectorals, upper trapezius and levator scapulae with weak deep neck flexors and lower trapezius — forward head, rounded shoulders. Lower crossed syndrome: tight hip flexors and thoracolumbar erectors with weak gluteals and deep abdominals — anterior pelvic tilt.
- Forward head posture multiplies the effective load on the cervical extensors; the commonly quoted figure adds roughly 4.5 kg of demand for every 2.5 cm the head drifts forward.
- Functional curves (leg-length difference, habitual stance) disappear on side-bending away or correction of the cause; structural curves do not.
Working up shoulder asymmetry in a 14-year-old
A school screening referral notes a right shoulder riding high. Observe first: from behind, shoulder and scapular levels, waist creases, pelvis; from the side, thoracic profile. Then the Adams test — the child bends forward, feet together, knees straight — and a right thoracic rib hump appears. That hump means rotation, and rotation means structural until proven otherwise.
Measure the angle of trunk rotation with a scoliometer over the apex; five degrees or more buys a standing posteroanterior radiograph. On the film, choose the most tilted vertebrae at each end of the curve, draw perpendiculars to their endplates, and read the angle of intersection — the Cobb angle. Suppose it reads 18 degrees: classify adolescent idiopathic scoliosis, observe with physiotherapeutic specific exercise (methods such as Schroth), and review every six months with Risser sign readings to gauge remaining growth, because progression rides on growth velocity.
Red flags that change everything: pain at night, neurological deficits, rapid progression, onset before age ten, or a left thoracic curve (which hides syringomyelia and other pathology more often than the right). Structural or not, the postural prescription still addresses the crossed-syndrome pattern found alongside — most adolescents with scoliosis need no "posture correction" of the curve itself, a distinction that saves pointless mirror-drilling.
How the exam frames it
Match-the-column questions pair tight and weak muscles in the crossed syndromes — pectorals with deep neck flexors, hip flexors with gluteals — and single-fact MCQs fix the Cobb threshold at 10 degrees and the rib hump on the convex side. Scheuermann's disease versus postural kyphosis is a recurring contrast: Scheuermann's is rigid, with at least three adjacent vertebrae wedged 5 degrees or more and irregular endplates. Functional-versus-structural differentiation by side-bending completes the standard set.
Frequently asked questions
At what Cobb angle is scoliosis diagnosed?
Ten degrees or more; below that a mild asymmetry is not labelled scoliosis.
What does the Adams forward bend test detect?
The rib or loin hump of vertebral rotation, screening for structural scoliosis; a scoliometer quantifies it.
Which muscles are tight and which weak in upper crossed syndrome?
Tight pectorals, upper trapezius and levator scapulae; weak deep neck flexors and lower trapezius.
How is a functional scoliosis differentiated from a structural one?
The functional curve corrects on side-bending away or with leg-length equalisation; a structural curve persists.
What radiographic features define Scheuermann's disease?
Rigid hyperkyphosis with three or more consecutive wedged vertebrae of at least 5 degrees and irregular endplates.