PHTY103 Lecture Notes - Lecture 9: National Journal, Abdomen, Multifidus Muscle
Document Summary
Week 8: the (cid:271)ody(cid:859)s (cid:396)espo(cid:374)se to i(cid:373)(cid:373)o(cid:271)ilisatio(cid:374), i(cid:374)a(cid:272)ti(cid:448)ity a(cid:374)d disuse: explain the physical changes that occur in body tissues (muscle, bone, cartilage tendon and ligaments) as a result of immobilisation, inactivity and disuse. Muscle, bone, cartilage, ligament and tendon are all adaptable (plastic) to some extent respond to mechanical demands placed on them, bone and muscle highly plastic. Load usually relates to either muscle activity or gravity (weight-bearing) Wolff(cid:859)s la(cid:449): (cid:396)e(cid:373)odelli(cid:374)g of (cid:271)o(cid:374)e is i(cid:374)flue(cid:374)(cid:272)ed a(cid:374)d (cid:373)odulated (cid:271)y (cid:373)e(cid:272)ha(cid:374)i(cid:272)al st(cid:396)esses. Bone to subjected to mechanical stress (load) leads to: loss of bone mineral density. Areas of the bone which usually weight bear decrease in mass and density. 3-fold reduction in load to failure (less load needed to lead to failure) 8-9% reduction in csa at femoral neck and proximal femoral region. 2% reduction in cortical density at tibia & femur (not in radius) Trabecular density reduced by 5% tibia, 12% femur, 4% lumbar spine (not in radius)
