6.1 Postural Assessment & Structural Deviations

Postural Assessment & Structural Deviations

Clinical Core: Static postural evaluation provides an essential observational baseline for identifying biomechanical strain, asymmetric joint loading, and predictable neuromuscular adaptations. In Canadian clinical practice, the therapist utilizes plumb line reference landmarks across three cardinal planes to differentiate between reversible functional adaptations and fixed structural pathologies.

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1. Principles of Static Postural Examination

Static posture reflects the alignment of body segments maintained with minimal muscular effort and energy expenditure against gravity. A balanced posture minimizes joint shear stress, balances ligamentous tension, and maintains the body's center of gravity (COG) directly over its base of support (BOS).

Examination Environment & Patient Protocol

• Physical Setup: A level floor, adequate ambient lighting, and a plumb line suspended from the ceiling or an aligned grid background positioned parallel to the line of gravity.
• Patient Preparation: Minimal, boundary-safe clothing (e.g., athletic shorts, sports bra, or tank top) to expose key bony landmarks while maintaining clinical comfort and dignity. The patient stands barefoot with feet placed comfortably hip-width apart.
• Uninstructed Stance: Instruct the patient to take three normal steps forward or march briefly in place, take a deep breath, and settle into their natural, unforced stance. Asking a patient to "stand up straight" prompts artificial, transient postural corrections that mask chronic habitual adaptations.
• Observational Sequencing: Systematically inspect the patient from three primary vantage points: lateral view (sagittal plane), anterior view (frontal and transverse planes), and posterior view (frontal and transverse planes).

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2. Plumb Line Reference Landmarks

The plumb line serves as a physical representation of the line of gravity. Deviations from this line indicate segmental displacements, gravitational shear, and compensatory counter-deviations elsewhere along the kinetic chain.

Lateral View (Sagittal Plane)

In an ideal sagittal alignment, the plumb line falls precisely through or adjacent to the following anatomical landmarks:

1. External Auditory Meatus: Bisects the center of the ear canal.
2. Bodies of the Cervical Vertebrae: Passes through the vertebral bodies, balancing the weight of the cranium over the cervical pillar.
3. Acromion Process: Bisects the tip of the shoulder joint.
4. Thoracic Trunk: Passes slightly anterior to the thoracic vertebral bodies, maintaining the normal convex kyphotic curvature.
5. Bodies of the Lumbar Vertebrae: Traverses the lumbar vertebral bodies, balancing the lordotic curve.
6. Greater Trochanter of the Femur: Bisects the hip joint axis, sitting slightly posterior to the hip center of rotation.
7. Knee Joint: Passes slightly anterior to the midline of the knee joint axis (immediately posterior to the patella), creating a passive extensor moment that stabilizes the knee with minimal quadriceps expenditure.
8. Lateral Malleolus: Passes approximately 2 to 3 cm anterior to the lateral malleolus, bisecting the calcaneocuboid joint.

Anterior View (Frontal & Transverse Planes)

The line of gravity should bisect the body into symmetrical left and right halves:

• Cranium & Face: Head is neutral with no lateral tilt or rotation; eyes, ear lobes, and temporomandibular joints are level.
• Shoulder Girdle: Clavicles are symmetrically horizontal; acromion processes and sternoclavicular joints are level.
• Thorax & Abdomen: Sternum lies strictly vertical along the plumb line; subcostal angles and waist angles (distance between arm and torso) are equal bilaterally.
• Pelvic Landmarks: Anterior Superior Iliac Spines (ASIS) lie on the same horizontal plane. Iliac crest heights are equal.
• Lower Extremities: Patellae face directly anteriorly (neither squinting medially nor pointing laterally ["grasshopper eyes"]). The Q-angle is within commonly cited normal ranges (about 10°–14° in males and 15°–17° in females). Genu valgum ("knock-knees") or genu varum ("bow-legs") is documented.
• Feet & Ankles: Medial and lateral malleoli are level relative to each other; feet exhibit symmetrical toe-out angles (approximately 5°–7°); medial longitudinal arches are preserved (absence of excessive pes planus or pes cavus).

Posterior View (Frontal & Transverse Planes)

From the posterior perspective, the plumb line aligns with the spinous processes:

• Cervicothoracic Axis: Occiput is level; cervical and thoracic spinous processes align in a straight vertical line without lateral curvature.
• Scapular Position: Spines of the scapulae align at T3; inferior angles align at T7. Vertebral borders sit parallel to the spine, spaced 5 to 7.5 cm (2 to 3 inches) from the spinous processes, lying flat against the thoracic cage without winging or tipping.
• Pelvic Landmarks: Posterior Superior Iliac Spines (PSIS) lie on the same horizontal plane. The gluteal folds are level.
• Lower Extremities: Popliteal creases are horizontal. The calcaneal (Achilles) tendon descends strictly vertically to the calcaneus; excessive calcaneal valgus (eversion) or calcaneal varus (inversion) is noted.

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3. Sagittal Plane Spinal Deviations

Alterations in sagittal plane curvature disrupt the shock-absorbing capacity of the spine, increasing shear stresses across intervertebral discs and facet joints.

   HYPERLORDOSIS         HYPERKYPHOSIS           FLAT BACK             SWAY BACK
    (Anterior Tilt)      (Dowager's Hump)      (Posterior Tilt)      (Pelvic Shift)

         ( ) Head             ( ) Forward Head       ( ) Head              ( ) Forward Head
          |                    /                      |                     /
         ) ( Cervical         ) ( Hyperlordotic       | Straight            ) ( Hyperlordotic
        (   ) Thoracic       (   ) Hyperkyphotic      | Thoracic           (   ) Long Kyphosis
         ) ( Hyperlordotic    ) ( Lordotic            | Straight            | Flat Lumbar
        /   \ Ant. Tilt      |   | Neutral           /   \ Post. Tilt      /   \ Pelvis Forward
       /     \              /     \                 /     \               /     \ Hyperextended

Hyperlordosis (Hollow Back)

Hyperlordosis is an excessive anterior curvature of the lumbar spine compared with the person's normal range, accompanied by an exaggerated anterior pelvic tilt:

• Pelvic Biomechanics: The ASIS tilts inferiorly relative to the PSIS, exceeding the normal anatomical incline (>10° in males, >15° in females). The sacral base angle increases, elevating compressive loads on the posterior lumbar facet joints (L4–S1).
• Muscular Adaptations: Facilitated and hypertonic hip flexors (iliopsoas, rectus femoris, tensor fasciae latae) and lumbar erectors; lengthened, inhibited, and weak abdominals (rectus abdominis, transversus abdominis, obliques) and gluteal musculature (gluteus maximus, gluteus medius).

Hyperkyphosis (Round Back)

Hyperkyphosis is an exaggerated posterior curvature of the thoracic spine exceeding 40°:

• Clinical Subtypes:
  • Dowager's Hump: A pronounced thoracic hyperkyphosis caused by multiple osteoporotic anterior wedge compression fractures, typically in older women (not the same as the cervicothoracic fat pad or "buffalo hump" seen in Cushing's syndrome).
  • Gibbus Deformity: A sharp, focal angular kyphosis resulting from anterior collapse of one or more adjacent vertebral bodies (e.g., tuberculosis of the spine [Pott's disease], severe compression fracture, or metastatic disease).
  • Scheuermann's Disease: Juvenile osteochondrosis of the thoracic spine characterized by wedge-shaped vertebral bodies (≥5° wedging across at least 3 contiguous vertebrae), irregular endplates (Schmorl's nodes), and rigid, unyielding thoracic kyphosis.
• Biomechanics & Adaptations: Exaggerated thoracic kyphosis causes secondary forward head posture (upper cervical hyperlordosis, lower cervical flexion) and scapular protraction. Anterior chest structures (pectoralis major, pectoralis minor, subclavius, anterior intercostals) become short and tight, restricting costal expansion during respiration.

Flat Back Posture

Flat back posture is characterized by the pathological loss or marked reduction of both normal lumbar lordosis and thoracic kyphosis:

• Pelvic Biomechanics: The pelvis is rotated in a rigid posterior pelvic tilt; the sacral base angle is diminished (<30°).
• Muscular Adaptations: Hypertonic and shortened hamstrings and rectus abdominis; elongated, weak, and disengaged lumbar erector spinae, multifidi, and hip flexors (iliopsoas).
• Functional Consequences: The straightened spine loses some of its natural shock-absorbing curvature, so axial loads are transferred more directly through the spine; clients often report fatigue with prolonged standing.

Sway Back Posture

Sway back posture involves a forward translation of the pelvis relative to the plumb line, combined with a posterior pelvic tilt:

• Segmental Displacements: The entire pelvis shifts anteriorly over the feet; the hips hyperextend; the lumbar spine flattens in its lower segment; the thoracic spine develops an elongated, displaced kyphosis that extends into the upper lumbar region; and the head and cervical spine project forward in compensation.
• Muscular Adaptations: Shortened and hypertonic hamstrings, internal obliques, and tensor fasciae latae; elongated and chronically weakened hip flexors (iliopsoas), external obliques, rectus abdominis, and lower thoracic extensors. The patient hangs passively on the anterior hip joint capsules and iliofemoral (Y) ligaments rather than engaging active muscular stabilizers.

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4. Frontal Plane Spinal Deviations: Scoliosis

Scoliosis is defined as an appreciable lateral deviation of the spine in the frontal plane, typically accompanied by rotational deformities in the transverse plane.

Structural vs. Functional Scoliosis

Differentiating between structural and functional scoliosis is a core clinical competency in Canadian registered massage therapy:

• Structural Scoliosis:
  • Pathophysiology: An irreversible, fixed lateral spinal curve coupled with fixed vertebral body rotation. The vertebral bodies rotate toward the convexity of the curve, while the spinous processes deviate toward the concavity.
  • Adam's Forward Bend Test: Positive. When the patient bends forward at the hips with knees straight and arms dangling, the rotated vertebrae force the attached ribs posteriorly on the convex side, forming a visible, palpable rib hump (rotational prominence). In the lumbar spine, a prominent lumbar paraspinal fullness appears on the convex side.
  • Reversibility: The curvature does not disappear with active side-bending, spinal flexion, or prone recumbency.
  • Etiologies: Idiopathic (80% of cases, commonly adolescent idiopathic scoliosis [AIS]), congenital hemivertebrae, neuromuscular (cerebral palsy, muscular dystrophy).
• Functional (Postural) Scoliosis:
  • Pathophysiology: A flexible, non-structural lateral deviation without fixed vertebral rotation or bony remodeling.
  • Adam's Forward Bend Test: Negative. The lateral curvature completely straightens, and the rib hump disappears as the patient flexes forward into an unloaded position.
  • Reversibility: Straightens completely in prone or supine recumbency, or when the underlying primary mechanical asymmetry is corrected (e.g., leveling the pelvis with an anatomical heel lift under a short leg).
  • Etiologies: Structural or functional leg length discrepancy (LLD), pelvic obliquity, unilateral muscle spasm (acute quadratus lumborum or psoas spasm), nerve root irritation (antalgic scoliosis leaning away from a disc protrusion), or asymmetric occupational posturing.

Cobb Angle Principles

The gold standard radiographic measurement of scoliosis severity is the Cobb angle:

1. The superior and inferior "end-vertebrae" (the most tilted vertebrae at the upper and lower limits of the curve) are identified.
2. Lines are drawn along the superior endplate of the upper end-vertebra and the inferior endplate of the lower end-vertebra.
3. Perpendicular lines are projected until they intersect; the angle formed is the Cobb angle.
4. Clinical Thresholds:
   • <10°: Normal physiological spinal asymmetry; not classified as true scoliosis.
   • 10°–24°: Mild scoliosis; monitored conservatively with therapeutic exercise and manual therapy.
   • 25°–40°: Moderate scoliosis; in skeletally immature adolescents, it is often managed with corrective bracing (e.g., Boston brace) plus scoliosis-specific exercise.
   • ≥40°–50°: Severe scoliosis; surgical (spinal fusion) consultation is usually considered, especially in growing adolescents. Very large thoracic curves (roughly 70°–90° or more) can reduce vital capacity.

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5. Janda's Muscle Imbalance Syndromes

Dr. Vladimir Janda identified that the neuromuscular system responds to chronic postural stress, sedentary habits, and repetitive loading with predictable patterns of muscle imbalance. Muscles are categorized into two functional groups: postural (tonic) muscles, which tend toward shortening and hypertonicity, and phasic muscles, which tend toward inhibition, lengthening, and weakness.

Upper Crossed Syndrome (UCS)

Upper Crossed Syndrome is characterized by a crisscrossing pattern of hyperactive and inhibited muscle groups in the cervicothoracic and shoulder complexes:

• Facilitated / Short / Hypertonic Arm: Connects the posterior cervicothoracic muscles (upper trapezius and levator scapulae) with the anterior chest musculature (pectoralis major and pectoralis minor). Additional facilitated muscles include the suboccipitals, sternocleidomastoid, and latissimus dorsi.
• Inhibited / Weak / Lengthened Arm: Connects the anterior cervical stabilizers (deep neck flexors: longus capitis, longus colli, rectus capitis anterior) with the posterior scapular stabilizers (middle trapezius, lower trapezius, rhomboids, and serratus anterior).
• Clinical Manifestations: Forward head posture, upper cervical hyperextension, loss of cervical lordosis in lower segments, protracted and elevated shoulders, scapular winging/anterior tipping, reduced glenohumeral abduction range, and increased vulnerability to subacromial impingement and cervicogenic headaches.

Lower Crossed Syndrome (LCS)

Lower Crossed Syndrome represents a reciprocal imbalance pattern crossing the pelvic girdle and lumbosacral junction:

• Facilitated / Short / Hypertonic Arm: Connects the anterior hip flexors (iliopsoas, rectus femoris, tensor fasciae latae) with the posterior thoracolumbar stabilizers (lumbar erector spinae, superficial multifidi, and latissimus dorsi). The adductor group and piriformis frequently demonstrate secondary facilitation.
• Inhibited / Weak / Lengthened Arm: Connects the anterior abdominal wall (rectus abdominis, transversus abdominis, internal/external obliques) with the posterior pelvic stabilizers (gluteus maximus, gluteus medius, and gluteus minimus).
• Clinical Manifestations: Exaggerated anterior pelvic tilt, hyperlordosis of the lumbar spine, hip flexion contracture, compensatory thoracic hyperkyphosis, hamstring overload (compensating for inhibited gluteus maximus during hip extension), and increased shear strain across the L5–S1 junction.