KIN 306: Lecture topic 8 or 9 about the spine

A demonstration of weight distribution using a bamboo rod with a 2-3 pound weight.
Observed behavior: the rod bends significantly under weight pressure, illustrating spinal curvature.

The cervical spine supports the weight of the head; weight falls slightly behind the cervical vertebrae.
When the cervical spine is extended, body weight is shifted in front of the thoracic vertebrae.
Description of lower arm muscles aiding thoracic spine flexion for posture maintenance.
Lumbar region: weight runs through lumbar vertebrae without significant muscle involvement (flexors/extensors) necessary for upright posture.
Acetabulum placement helps maintain balance with minimal muscle activity.

Mention of physical fatigue occurring in feet, ankle, hips, quadriceps during prolonged standing jobs.
Less muscle fatigue in the back unless there is poor posture.

Common practice: chiropractors and physiotherapists assess posture from a side view in the sagittal plane.
Assess posture quality which might influence treatment decisions like exercises and stretches.
Recognition that good posture visually might not equate to structural health.

The spine consists of numerous vertebrae including cervical, thoracic, lumbar, and sacral components.
Abnormal alignment at one vertebra may cause compensatory alignments at other vertebrae, making visual assessments misleading.
Trend in the last two decades: focus on vertebral level analysis rather than overall spinal health.

Definition: any pair of adjacent vertebrae, e.g., T6-T7, L1-L2, C4-C5.
Structure components: intervertebral disc, facet joint capsules (two), and associated ligaments.
FSU has three main joints: interbody joint (intervertebral disc) and two facet joints.

FSU movements can be described using a coordinate system (3D axes).
Axes include:
- Medial-lateral axis: sagittal plane for flexion and extension.
- Anterior-posterior axis: frontal plane for lateral flexion.
- Vertical axis: transverse plane for axial rotation.
Alternative terminologies in clinical settings:
- Forward/backward bending (for flexion/extension)
- Side bending (for lateral flexion)
- Rotation (for axial rotation)

Recent studies indicate physiotherapy experts struggle to consistently assess spinal movements during exercises like squats and deadlifts.
Motion analysis data showed inaccuracies in movement detection, highlighting challenges in traditional observational methods.
Importance of accurate data in biomechanical assessments of spinal issues.

Difficulty in palpating spinal processes (spinous/transverse processes) contributes to diagnostic inaccuracies.
Measurement accuracy limitations lead to widespread misconceptions about spinal health.
Visual assessments yield poor accuracy in estimating spinal dynamics, best suited for global posture assessment not local details.

Visual assessments: inherently inaccurate for precise measurements at FSU level.
Dynamic assessments provide richer data for understanding movement patterns.
Need for medical imaging (e.g., X-rays, MRIs) for accurate spinal analysis.

X-rays: Rapid assessment of spine posture and alignment, including local and global perspectives.
MRI: Does not utilize radiation and aids in viewing bones and discs, although static in nature.
Challenge: Diagnostic imaging can involve radiation exposure and should be minimized to necessity.

Exercise example: "Good Morning" exercise emphasizes intentional spinal positioning under load.
Potential injury risks exist with excessive flexion or extension in any joint, including the spine.

Backward bending (extension) limits: typically 1 degree motion possible at lumbar FSU during significant extension.
Forward bending (flexion) capabilities: exhibit greater motion (5-7 degrees at each FSU).
Slump sitting positions: maximal flexion measured at 10-12 degrees at lumbar FSU indicating spine design favoring flexion.

Daily activities create varying flexion and extension demands on the lumbar spine.
Spinal flexion is integral for common actions (e.g., sitting, bending).
Overemphasis on avoiding spinal flexion can lead to neglecting the spine's functional design.

Proper progression in exercise is crucial, especially for individuals with lower back pain.
Safe exercise familiarization can lead to improvements in strength and reduce injury risk.

Stress application studies on lumbar vertebrae show tough tolerance to flexion under controlled lab conditions but highlight susceptibility at specific angles.
Understanding spinal limits aids injury prevention strategies, particularly concerning excessive or improper movements.

Differentiation between transient and chronic loading and their respective impacts on the spine.
Chronic compression stress influences bio-mechanical health negatively; certain loads can enhance risks if sustained over time.

NIOSH identified safe compression load limits (3,500 Newtons) for occupational safety.
Careful assessment of lifting techniques with respect to weight distribution relative to the body is pivotal:
- Example: Carrying a 20kg load more than 40 centimeters away from the body exceeds safe limits.

Compression force contributors include body weight and lifting dynamics during physical activities.
Muscle strength, posture during lifting, and external load requirements all synergistically affect overall spinal loading.

Research insights emphasize the importance of elevated physical fitness and attention to postural norms to mitigate chronic injury risks.
Evidence suggests a physiological need for periodic unloading and positive adaptations through movement.

Anomalous duty cycles both through inactivity and chronic overload can foster degrading of structural spinal integrity.
Health implications of both overtraining and poor posture must be addressed through balanced dynamics and careful rehabilitation.