The Biomechanics of the Human Spine Prepared by
The Biomechanics of the Human Spine Prepared by Yassr Y. Kahtan 1 Based upon TK Koesterer, Ph. D. , ATCHumboldt State University
2 Objectives Explain how anatomical capabilities of the spine. structure affects movement Identify factors influencing relative mobility and stability of different regions of the spine. Explain the ways in which spine is adapted to carry out its biomechanical functions. Explain the relationship between muscle location and the nature and effectiveness of muscle action in the trunk.
3 Structure of the Spine Vertebral Column Motion Segment Vertebrae Intervertebral Discs Annulus fibrosus Nucleus pulposus
4 Structure of the Spine Ligaments Anterior longitudinal ligament Posterior longitudinal ligament Supraspinous ligament Intertransverse ligaments Ligamenta flava Ligamentum Flavum
5 Spinal Curves Influenced by heredity, pathological conditions, individual’s mental state, and forces to which the spine is habitually subjected. Prestress Primary Spinal Curve Secondary Spinal Curve Lordosis Kyphosis Scoliosis
6 Movements of the Spine Flexion Extension Hyperextension Lateral Flexion Rotation
7 Muscles of the Spine Muscles of neck and trunk named in pairs, with one on the left and the other on the right side of body. Anterior Aspect Posterior Aspect Lateral Aspect
8 Anterior Aspect Bilateral tension development results in flexion of head. Unilateral tension contributes to: development in prevertebrals lateral flexion of head toward contracting muscles or, to rotation of head away from contracting muscles Abdominals
9 Posterior Aspect Primary cervical extensors: splenius capitis splenius cervicis Thoracic and Lumbar Muscle groups: erector spinae Semispinalis deep spinal muscles
10 Lateral Aspect Many muscles of neck and trunk cause lateral flexion when contracting unilaterally, but either flexion or extension when contracting bilaterally. Muscles: sternocleidomastoid levator scapulae scalenus anterior, posterior and medius Lumbar region: quadratus lumborum, psoas major
11 Loads on the Spine Forces acting on spine: Body weight Tension in the spinal ligaments Tension in surrounding muscles Intraabdominal pressure Any applied external loads Flexion Relaxation Phenomenon Body Movement Speed Intraabdominal Pressure
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14 Summary Although vertebrae adhere to characteristic shape, there is a progression in size and orientation of articular facets throughout the spinal column. Each pair of adjacent vertebrae with intervening soft tissues called a motion segment. Many forces act upon spine intraabdominal pressure etc). (body weight,
15 Don’t Forget ! Muscles of the Spine, table 9 -1. (p. p. 288). Sample Problem 9. 1 (p. p. 296).
16 Thank you for Listening
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