ESS 303 – Biomechanics Trunk: Thorax, Spinal Column & Pelvis
7 Cervical 12 Thoracic 5 Lumbar Sacrum: 5 Fused Sacral Vertebrae) Coccyx: 3-5 Coccygeal Vertebrae Intervertebral Disks Intervertebral Formina
Bony Landmarks of the Vertebrae
Vertebral Bodies
Intervertebral Disks Shock absorption Amphiarthrodial joints between vertebrae Disk injuries – bending forward → nucleus pulposus is displaced backwards Disk degeneration Stress loading → reduction in disk thickness → loosening of longitudinal ligaments → increased movement Decreased thickness → narrowing of vertebral foramen → pain, inflammation, poor nutrition Both of above cause back pain
Vertebral Column Functions Support body weight Protect the spinal cord Provide mobility Abnormal curvatures Kyphosis: thoracic & sacral Lordosis: cervical, pelvic & lumbar Scoliosis: lateral deviation(s)
Kyphosis Lordosis
(First 7) (Next 3 – 8, 9, & 10) (Last 2 – 11 & 12)
Biomechanics of Breathing Visualize a bucket handle External intercostals and sternocleidomastoids – elevate ribs – inspiration Internal intercostals – depress ribs - expiration
Movements & Major Muscles Flexion: Rectus abdominis, internal & external obliques Extension: Erector spinae Lateral flexion: Internal & external obliques & erector spinae Rotation: Internal (same side) & external (opposite side) obliques & erector spinae (opposite side)