Foundations of Occupation: Kinesiology in Daily Life

Foundations of Occupation: Kinesiology in Daily Life

Week 14: Posture, Respiration, and Swallowing

Introduction

• Discusses the significance of posture, respiration, and swallowing in the context of daily life and occupational therapy.

Lecture Objectives

• By the end of the lecture, the learner should be able to:

  • Define base of support (BOS) and describe its impact on function.

  • List factors affecting center of gravity (COG) and BOS and their effect on stability.

  • Describe static and dynamic posture and postural control.

  • Describe the relationships between posture, reduction of stress, and energy expenditure.

  • Describe “ideal” posture and the significance of the line of gravity (LOG) in the analysis of posture.

Posture

• Static Posture:

  • Body and segments are aligned and maintained in certain positions.

• Dynamic Posture:

  • Body and segments are in motion.

Functions of Posture

• Controls the body's orientation in space.

• Maintains the center of mass over the base of support via muscle activation.

• Stabilizes the head for proper gaze orientation towards the environment.

Ergonomic Workstation Recommendations

• Neck: Keep neck straight.

• Head: Align ears, shoulders, and hips; avoid tilting head forward or backward; use a book prop when reading.

• Eyes: Top of computer screen should be at eye-level; center laptop screen at a 30° angle downward from eye level.

• Elbows: Keep bent at 90-100°, resting lightly on armrest, near the sides.

• Chair: Mid to tall back with lumbar support, adjustable height and depth.

  • Sit all the way back in the seat; avoid sliding forward.

  • Take breaks from sitting every 30 minutes.

• Chair Height: Adjust so hips are at 90° or slightly more, feet flat on the floor or on a footrest.

• Keyboard: Position just below elbows; avoid wrist bending.

• Mouse: Use a gel wrist rest, move with whole arm, not just the wrist.

Ideal Posture (Standing)

• Achieved when the plumb line falls through specific body reference points; leads to:

  • Optimal reduction of energy expenditure.

  • Reduction of stress on structural components.

  • Reduction of loads on supporting ligaments and muscles.

Line of Gravity (LOG) and Posture

• The LOG is not perfectly stationary.

• Its location relative to joint axes determines gravitational torque, impacting postural stability.

Analysis of LOG in Ideal Posture

• Head: LOG anterior to atlanto-occipital joint.

• Trunk: When vertebral curves align, LOG passes through midline.

• Hip: LOG posterior to the axis of rotation.

• Knee: LOG posterior to axis of rotation.

• Ankle: LOG anterior to the axis of rotation.

Postural Control

• Defined as the ability to maintain stability of the body and its segments under various forces threatening equilibrium, involving:

  • Postural sway

  • Reactive responses

  • Anticipatory responses

Postural Abnormalities

• Structural Curves: Changes in body articulations (e.g., vertebrae). Can be corrected through surgical intervention or bracing.

• Nonstructural Curves: Curves that can be reversed if the cause is treated.

Types of Postural Distortions

• Primary Postural Distortion: Problem arises in an area of the body.

• Secondary Postural Distortion: Issues in one area affect another, creating a “snowball” effect.

Factors Affecting Stability

• Height of COG Above BOS:

  • Lower COG = more stability; BOS defined as the part of the body in contact with the supporting surface (like ground).

  • Stability increases with a lower COG.

• Size of BOS:

  • Wider BOS = more stable.

• Location of the Gravity Line:

  • If weight is added, postural adjustments must be made.

Example: High Heels and Stability

• High heels raise the COG and narrow the BOS, resulting in postural changes:

  • Anterior pelvic tilt, hip flexion, lumbar lordosis, scapular retraction.

  • Prolonged effects can shorten hip flexors, stress vertebrae, and alter shock absorption leading to gait changes, including

  • Altered swing phase; shortened hamstrings and gastrocnemius; weakened quadriceps.

Respiration

Learning Objectives

• By the end of the lecture and lab, learners will be able to:

  • List key structures and muscles (primary and accessory) in respiration.

  • Describe processes of inspiration and expiration.

  • Explain the impact of clinical conditions like COPD on respiration.

  • Differentiate between swallowing and feeding/eating.

  • Describe the oral, pharyngeal, and esophageal phases of normal swallowing.

  • Discuss the relationship between swallowing, posture, and respiration.

Anatomy of Respiration

• Key structures include the rib cage (12 ribs and cartilage), thoracic vertebrae, and sternum.

• Rib Articulation:

  • Ribs articulate with thoracic vertebrae posteriorly and sternum anteriorly.

  • Provide attachment points for intercostal muscles, erector spinae, and abdominals.

Motion of Ribs during Inhalation

• Inhalation increases volume of thorax:

  • Medial-lateral (Bucket Handle): Ribs move like a bucket handle.

  • Anterior-posterior (Pump Handle): Ribs move in a pump handle motion.

Phases of Breathing

• Inspiration: Involves thoracic expansion and increase in thoracic volume.

• Expiration: Thoracic volume decreases.

• Resting vs. Deep/Forced Respiration:

  • Differentiates between quiet breathing and forceful breathing techniques.

Prime Movers of Respiration

• Inspiration:

  • Diaphragm, external intercostals, and accessory muscles for forced/deep inspiration.

• Expiration:

  • Relaxation of inspiratory muscles, elastic recoil, with internal intercostals and abdominals assisting in forced/deep expiration.

Clinical Application: COPD

• COPD leads to hyperinflation of the lungs due to alveolar wall destruction, causing air retention post-exhalation.

• Barrel Chest Appearance: Thorax rests in an inspiratory position due to over-utilization of accessory muscles to compensate for restrictive lung function.

Diaphragmatic Breathing Techniques

• Important exercises aimed at improving breathing efficacity include techniques for proper diaphragmatic function.

Swallowing

Learning Objectives

• By end of the lecture, learners should be able to:

  • Describe the complex swallowing process involving various muscles.

  • Explain phases of normal swallowing: oral, pharyngeal, and esophageal.

Anatomy and Complexity of Swallowing

• Involves muscles of mastication, labial function, tongue movement, palate, pharynx, and larynx.

• Coordination with respiration is essential as breath is halted during swallowing.

Occupational Therapy and Swallowing

• Involves interdisciplinary teams including speech and language pathologists.

• Evaluative methods encompass bedside and videofluoroscopic evaluations to assess swallowing competencies across various clinical populations.

Swallowing vs. Feeding/Eating

• Swallowing: Involves oral, pharyngeal, and esophageal management of a bolus, including swallowing dynamics.

• Feeding/Eating: Includes the occupational performance components of mealtimes, utensil utilization, and coordination of eating activities.

Phases of Swallowing

• Oral Phase:

  • Voluntary; bolus is formed and moved posteriorly within 1-3 seconds.

• Pharyngeal Phase:

  • Involuntary and brainstem-triggered; starts when bolus reaches the oropharynx, with elevation of the larynx and closure of the airway for protection.

• Esophageal Phase:

  • Involuntary control for 8-20 seconds, marked by peristaltic contractions driving the bolus into the stomach.

Goals of a Swallowing Program

• Ensure adequate nutrition and hydration.

• Promote safety during feeding to prevent aspiration and pneumonia.

• Identify risk factors leading to penetration (entry of food into laryngeal vestibule) or aspiration (entry into the lower airway).

Swallowing Considerations

• Ideal positioning (60-90 degrees) for safe swallowing.

• Varieties of food textures and consistencies categorized for therapeutic purposes:

  • Puree, mechanical soft, thin liquids, thickened liquids.