Study Notes on Posture in Physical Therapy

Introduction to Posture in Physical Therapy

  • Importance of posture in physical therapy (PT) evaluations

    • Nearly every PT evaluation includes a reference to posture.

    • Physical therapists can make a significant impact on patient outcomes by addressing posture immediately when meeting the patient.

    • Initial exercise programs can be designed based on the assessment of the patient’s posture.

Objectives of the Lesson

  • Define normal posture to establish a foundation for understanding abnormal posture.

  • Understand the concept of the line of gravity in static posture evaluation.

    • The line of gravity passes through several anatomical landmarks:

    • Mastoid process

    • Cervical vertebral bodies

    • Acromion (or AC joint)

    • Glenohumeral joint

    • Lumbar vertebrae

    • Anterior to the second sacral vertebra

    • Slightly posterior to the hip joint

    • Slightly anterior to the knee and the ankle

    • Significance of the line of gravity in maximizing the passive system (use of bones, ligaments, joint capsules) for support rather than relying on muscle activity.

Static vs. Dynamic Posture

  • Static Posture: The alignment of the body when at rest.

  • Dynamic Posture: The alignment of the body during movement.

    • Influenced by:

    • Muscle strength

    • Flexibility

    • Neuromuscular coordination

  • Components of dynamic posture:

    • Passive Structures: Bones, ligaments, and joint capsules (noncontractile elements).

    • Active System: Muscles (both superficial/global and deep/segmental) that provide active stabilization against gravity.

    • Neural System: The central nervous system coordinates the timing, intensity, and sequencing of muscle activation

    • Example: Activation of the transverse abdominis occurs prior to lifting any object.

Passive Control in Posture

  • Neutral Zone: The mid-range position of spinal segments with minimal passive resistance to movement.

  • Elastic Zone: Represents increased resistance experienced when moving out of the neutral zone.

  • Golgi tendon organs play a role in informing the central nervous system about body position in space.

Control Systems of Dynamic Posture

  • Three-legged stool model of dynamic posture:

    1. Passive Control (bones, ligaments, joint capsules)

    2. Active System (muscles): differentiate between global and segmental muscles:

    • Global muscles (e.g., erector spinae, longissimus, iliocostalis) facilitate larger range motions.

    • Segmental muscles (e.g., multifidi) provide stability and control individual vertebral segments.

    1. Neural System: Quick action on muscle activation as dictated by the nervous system (timing, anticipation of loads).

Tonic vs. Phasic Muscles

  • Tonic Muscles:

    • Characteristics:

    • Strong, designed to oppose gravity.

    • Higher resting tone, always slightly active ('antigravity' muscles).

    • Slow twitch type I fibers; high endurance.

    • Examples:

    • Multifidi

    • Pectoralis major and minor

    • Upper trapezius

    • Soleus

    • Iliopsoas

    • Transverse abdominis

  • Phasic Muscles:

    • Characteristics:

    • Produce larger movements, fast twitch type II fibers.

    • Fatigue quickly; activated on demand.

    • Examples:

    • Rhomboids

    • Lower trapezius

    • Middle trapezius

    • Rectus abdominis and obliques

    • Gluteals

    • Vastus medialis and lateralis

Muscle Imbalances and Postural Alignment

  • Muscle imbalances occur due to improper postural alignment:

    • Agonist: The muscle being worked.

    • Antagonist: The muscle opposing the agonist.

    • Improper alignment results in:

    • Shorter, overworked muscles can fatigue.

    • Lengthened muscles become weak due to the length-tension relationship.

  • Considerations for analyzing postures:

    • Identify potentially overstretched muscles that may be weak.

    • Identify potentially shortened muscles that may be painful or lack flexibility.

Examination of Common Postural Defects

  • Notable conditions related to postural alignment:

    • Kyphosis: Increased thoracic curvature, often resulting in rounded shoulders.

    • Lordosis: Increased lumbosacral angle, with anterior pelvic tilt.

    • Swayback: Anterior pelvic positioning leading to relative hip extension.

    • Flat Back: Characterized by a posterior pelvic tilt.

    • Forward Head Posture: Characterized by increased thoracic kyphosis and protracted shoulders.

    • Scoliosis: Lateral curvatures of the spine.

  • Importance of assessing asymmetries in postural analysis, noting that an asymmetry may not necessarily indicate dysfunction.

Practical Application

  • Importance of identifying weak muscles needing strengthening and shortening needing flexibility interventions.

  • Educate patients on maintaining correct postural alignment during functional mobility activities.

  • Conclusion: Emphasize the importance of looking beyond merely muscular imbalance to educate patients on the intricacies of posture and stability during movement.

Additional Resources

  • Watch three video clips embedded in the lab for a sequential approach to analyzing posture.

    • Each video highlights the practitioner’s approach, which starts from the feet and moves upwards, assessing anterior, posterior, and lateral views.

    • These resources offer valuable methodologies for evaluating the posture of patients effectively.