Scoliosis

Populations and Risk Factors

• Adolescent idiopathic scoliosis (AIS) accounts for approximately 80% of structural scoliosis; affects 1-3% of the adolescent population
• Girls are affected 7-10 times more frequently than boys for curves requiring treatment (>30 degrees); overall prevalence is more equal, but girls' curves are far more likely to progress
• Onset during the rapid growth spurt (ages 10-16); curves detected before menarche are at highest risk of progression because significant skeletal growth remains
• Risser sign (iliac crest apophysis ossification, graded 0-5) predicts remaining growth — Risser 0-1 indicates high progression risk; Risser 4-5 indicates near-skeletal maturity and low progression risk
• Neuromuscular conditions (cerebral palsy, muscular dystrophy, spinal muscular atrophy, spinal cord injury) can produce secondary structural scoliosis through asymmetric muscle pull on the developing spine
• Congenital vertebral anomalies (hemivertebra, fused vertebrae, absence of vertebral elements) produce congenital scoliosis that is present from birth
• Leg-length discrepancy (structural or functional) is the most common cause of functional scoliosis — the spine curves to compensate for the pelvic obliquity
• Family history — first-degree relatives of AIS patients have a 10-fold increased risk; multiple gene loci are implicated

Causes and Pathophysiology

Structural vs. Functional Scoliosis — The Fundamental Distinction

• Structural scoliosis: the vertebral bodies are wedge-shaped and rotated; the intervertebral discs are asymmetrically compressed; the ribs and posterior elements are permanently deformed; the curve does NOT disappear with position change (persists in forward bending, side-lying, and suspension) — this is why Adam's forward bend test is definitive
• Functional (nonstructural) scoliosis: the vertebrae are normally shaped; the curve is caused by an external factor (leg-length discrepancy, muscle guarding from pain, habitual asymmetric posture); the curve DISAPPEARS with position change (straightens in forward bending, resolves when the causative factor is corrected) — treat the cause, not the curve
• Clinically, this distinction determines the entire treatment approach: functional scoliosis requires identification and correction of the underlying cause; structural scoliosis requires monitoring, bracing, or surgery depending on severity and growth remaining

Vertebral Rotation and the Rib Hump

• In structural scoliosis, the vertebral bodies rotate toward the convex side of the curve while the spinous processes rotate toward the concave side
• In the thoracic spine, this vertebral rotation pushes the attached ribs posteriorly on the convex side, creating the rib hump — a visible and palpable posterior prominence on the convex side during forward bending
• In the lumbar spine, vertebral rotation creates a paravertebral prominence on the convex side (there are no ribs to translate, but the transverse processes and overlying musculature bulge posteriorly)
• The rib hump is the clinical hallmark of structural scoliosis — its presence on Adam's forward bend test confirms the diagnosis and distinguishes structural from functional curves

Cobb Angle — Quantifying Severity

• The Cobb angle is measured on a standing AP radiograph: lines are drawn along the superior endplate of the most tilted vertebra above the curve apex and the inferior endplate of the most tilted vertebra below the apex; the angle between these lines (or their perpendiculars) is the Cobb angle
• Clinical significance by Cobb angle:
• <10 degrees: normal variant; not classified as scoliosis
• 10-20 degrees: mild scoliosis; observation with serial monitoring every 6 months during growth
• 20-40 degrees: moderate scoliosis; bracing indicated if growth remains (Risser 0-2); bracing aims to prevent progression, not correct the curve
• >40-45 degrees: severe scoliosis; surgical correction indicated (spinal fusion with instrumentation) if growth remains; curves >50 degrees may continue to progress even after skeletal maturity
• Massage therapists do not measure Cobb angle but must understand the concept to interpret medical reports and understand why certain curves are braced or surgically managed

Curve Classification and Nomenclature

• Curves are named for the convex side: a right thoracic curve has the convexity (apex) pointing to the right
• Single (C-curve): one primary curve; more common in lumbar or thoracolumbar scoliosis
• Double (S-curve): a primary curve with a compensatory curve above or below — the compensatory curve develops to keep the head centered over the pelvis; the compensatory curve is typically more flexible and smaller than the primary curve
• Right thoracic curve is the most common pattern in AIS — the primary curve is in the thoracic spine with convexity to the right; a compensatory left lumbar curve develops below
• The compensatory curve chain is clinically important: treating only the primary curve without addressing the compensatory curve leaves the patient with an unbalanced spine; the compensatory curve has its own muscle imbalances that must be assessed

Convex/Concave Muscle Patterns

This is the essential pathophysiological concept that grounds the palpation and treatment approach:

• Concave side (short side): muscles are chronically shortened, hypertonic, and fibrotic — the paraspinals, quadratus lumborum, intercostals, and lateral trunk musculature on the concave side are held in a permanently shortened position; they develop trigger points, fascial adhesions, and reduced elasticity; this side typically has more pain because the shortened muscles are working against their optimal length-tension relationship
• Convex side (long side): muscles are chronically elongated, stretched, and often weak — the same muscle groups on the convex side are held in a lengthened position; they may develop strain-pattern pain from eccentric overload; in the thoracic region, the elongated intercostals and rib cage deformity can restrict respiratory mechanics
• Rotational component: the deep rotators (rotatores, multifidi) are asymmetrically active — they are hypertonic on the side toward which the vertebrae are rotating (convex side at deep segmental level, concave side at superficial level); this creates a complex layered pattern where superficial and deep muscle involvement may be on opposite sides
• Compensatory curves: each curve has its own convex/concave pattern, so a double S-curve has the concave/convex sides reversed at each level — the right thoracic curve has left-side concavity in the thorax but right-side concavity in the compensatory lumbar curve; this means the hypertonic side alternates with each curve

Respiratory and Systemic Consequences (Severe Cases)

• Severe thoracic scoliosis (>60-70 degrees) compresses the thoracic cavity on the concave side, reducing lung volume and ventilatory capacity
• The rib cage deformity restricts chest wall expansion on the concave side; the convex side ribs are displaced posteriorly, further reducing thoracic compliance
• In extreme cases (>80-90 degrees), cardiac compression and pulmonary hypertension can develop from chronic restrictive lung disease
• These systemic consequences are not relevant to most massage therapy clients (who typically present with mild-to-moderate curves) but explain why severe curves require surgical intervention

Signs and Symptoms

Mild-to-Moderate Scoliosis (10-40 degrees Cobb)

• Postural asymmetry: uneven shoulders (one higher), uneven waistline (one side more indented), one hip higher or more prominent, uneven scapular positions (one winged or more prominent)
• Muscular pain and tension: chronic aching on the concave side (shortened, hypertonic muscles); possible strain-type pain on the convex side (elongated muscles under eccentric load); pain typically worsens with prolonged static postures and fatigue
• Restricted ROM: side-bending toward the concave side is typically more limited (muscles already shortened cannot shorten further); trunk rotation may be asymmetric
• Rib hump on the convex side visible during forward bending (structural scoliosis)
• Functional impact: cosmetic concerns (especially in adolescents), muscle fatigue with sustained postures, reduced exercise tolerance

Severe Scoliosis (>40-45 degrees Cobb)

• All findings above, plus:
• Visible spinal deviation in standing (does not require forward bending to observe)
• Marked rib cage deformity with posterior rib prominence (convex side) and anterior rib crowding (concave side)
• Nerve root irritation from foraminal narrowing on the concave side — radicular symptoms are possible in severe curves
• Restricted lung capacity: dyspnea on exertion; reduced exercise tolerance beyond musculoskeletal fatigue
• Cardiac involvement in extreme cases (>80-90 degrees)

Structural vs. Functional — Clinical Differentiation

Assessment Profile

Subjective Presentation

• Chief complaint: may present with postural concerns ("one shoulder is higher," "my clothes don't hang straight"), muscular pain along the spine (typically concave side), or may be asymptomatic and diagnosed incidentally during screening; adolescents often present after school screening or parental observation; adults may present with progressive back pain and fatigue in long-standing curves
• Pain quality: dull, aching, muscular — predominantly on the concave side; described as fatigue-type pain that worsens through the day and with sustained postures; not sharp, shooting, or radicular unless severe curve causes foraminal narrowing
• Onset: insidious; typically noticed during adolescent growth spurt; family member or school nurse may have identified the asymmetry; adults with long-standing scoliosis may report gradual worsening of symptoms with age as degenerative changes superimpose on the structural curve
• Aggravating factors: prolonged static postures (sitting, standing), sustained one-sided activities, carrying loads, fatigue; exercise that loads the spine asymmetrically
• Easing factors: position changes, stretching (particularly the concave side), rest, supportive seating; heat to the concave-side musculature
• Red flags: rapid curve progression in a skeletally immature patient (still growing) → refer for orthopedic monitoring; bracing may be needed; new-onset neurological symptoms (radiculopathy, weakness) in a patient with known scoliosis → refer for medical assessment to rule out cord compression or progressive deformity

Observation

• Local inspection: asymmetric shoulder heights; asymmetric scapular positions (one winged or more prominent); uneven waistline; one hip higher or more prominent; visible spinal lateral deviation in moderate-to-severe cases; rib hump on forward bending (structural); paravertebral prominence in lumbar curves; skin creases asymmetric on the trunk; in post-surgical patients, a midline scar with possible visible hardware (rod) prominence
• Posture: the entire postural chain compensates for the curve — the compensatory curve above or below the primary curve attempts to center the head over the pelvis; lateral trunk shift; pelvic obliquity (may be cause or effect depending on structural vs. functional); head tilt toward the convex side of the upper curve; shoulder elevation on the concave side of the thoracic curve
• Gait: generally normal in mild-to-moderate scoliosis; may show asymmetric arm swing and lateral trunk sway in more severe curves; Trendelenburg gait if hip abductor weakness has developed on one side; in functional scoliosis from leg-length discrepancy, the gait asymmetry is the primary finding

Palpation

• Tone: concave side — hypertonic, shortened paraspinals (erectors, multifidi), quadratus lumborum, intercostals, and lateral trunk musculature; the shortness is chronic and may feel fibrotic rather than acutely spasmed; convex side — elongated, often weaker musculature that may feel taut from eccentric strain rather than short and hypertonic; the deep rotators (multifidi) at the curve apex are asymmetrically active — hypertonic on the side of rotation; in a double curve, the concave/convex pattern reverses at each curve level, creating alternating bands of hypertonic and elongated tissue
• Tenderness: predominantly on the concave side — tender trigger points in the shortened paraspinals and QL; periosteal tenderness at the rib angles on the concave side (compressed ribs); tenderness at the curve apex from maximal rotational stress; the convex side may be tender from eccentric overload but is typically less painful than the concave side; no referred path tenderness along nerve trunks unless foraminal narrowing at the concave side produces radiculopathy
• Temperature: typically normal bilaterally; no inflammatory component in idiopathic scoliosis
• Tissue quality: concave side — fibrotic, inelastic, ropy texture in the paraspinals and QL consistent with chronic shortening; trigger points in the intercostals and paraspinal muscles; reduced fascial mobility; convex side — musculature may feel thinned and less dense from chronic elongation; the rib hump area on the convex side has a characteristic firm, bony feel from the displaced ribs; the thoracolumbar fascia is asymmetrically restricted (tighter on the concave side)

Motion Assessment

• AROM: side-bending toward the concave side is most limited (shortened muscles cannot shorten further); side-bending toward the convex side may be relatively full or mildly limited; rotation is asymmetric — restricted toward the convex side in the thoracic spine (the vertebrae are already rotated toward the convex side, so further rotation in that direction is blocked); forward flexion may reveal the rib hump (Adam's test position); in functional scoliosis, AROM may normalize the curve (key differentiating finding)
• PROM / end-feel: firm, tissue-stretch end-feel on side-bending toward the concave side — represents shortened musculature and fascial restriction, not bony block (unless severe with wedged vertebrae); comparing PROM with AROM: if PROM significantly exceeds AROM on the concave side, there is potential for therapeutic gain through soft tissue release; if PROM equals AROM with a hard end-feel, the restriction is structural (bony) and not amenable to soft tissue intervention
• Resisted testing: generally normal strength bilaterally in mild-to-moderate cases; convex-side paraspinal and scapular muscles may test weaker from chronic elongation; hip abductor weakness may be present on the side of the elevated pelvis; resisted trunk rotation strength is typically asymmetric

Special Test Cluster

Progression screening: In skeletally immature patients, document the curve findings and refer for orthopedic assessment. Curves >20 degrees with Risser sign 0-2 are at high risk of progression and may require bracing. MT does not monitor curve progression — this requires serial radiographs.

Differential Assessment