Heat stress increases limb blood flow and cardiac output (Q) in humans, presumably in sole response to an augmented thermoregulatory demand of the skin circulation. Here we tested the hypothesis that local hyperthermia also increases skeletal muscle blood flow at rest and during exercise. Hemodynamics, blood and tissue oxygenation, and muscle, skin, and core temperatures were measured at rest and during exercise in 11 males across four conditions of progressive whole body heat stress and at rest during isolated leg heat stress. During whole body heat stress, leg blood flow (LBF), Q, and leg (LVC) and systemic vascular conductance increased gradually with elevations in muscle temperature both at rest and during exercise (r(2) = 0.86-0.99; P < 0.05). Enhanced LBF and LVC were accompanied by reductions in leg arteriovenous oxygen (a-vO(2)) difference and increases in deep femoral venous O(2) content and quadriceps tissue oxygenation, reflecting elevations in muscle and skin perfusion. The increase in LVC occurred despite an augmented plasma norepinephrine (P < 0.05) and was associated with elevations in muscle temperature (r(2) = 0.85; P = 0.001) and arterial plasma ATP (r(2) = 0.87; P < 0.001). Isolated leg heat stress accounted for one-half of the increase in LBF with severe whole body heat stress. Our findings suggest that local hyperthermia also induces vasodilatation of the skeletal muscle microvasculature, thereby contributing to heat stress and exercise hyperemia. The increased limb muscle vasodilatation in these conditions of elevated muscle sympathetic vasoconstrictor activity is closely related to the rise in arterial plasma ATP and local tissue temperature.

Bone and joint changes in cerebral palsy result from muscle spasticity and contracture. The spine and the joints of the lower extremity are most commonly affected. Scoliosis may progress rapidly and may continue after skeletal maturity. Increased thoracic kyphosis and lumbar lordosis, spondylolisthesis, spondylolysis, and pelvic obliquity may accompany the scoliosis. Progressive hip flexion and adduction lead to windswept deformity, increased femoral anteversion, apparent coxa valga, subluxation, deformity of the femoral head, hip dislocation, and formation of a pseudoacetabulum. In the knee, flexion contracture, patella alta, and patellar fragmentation are the most commonly seen abnormalities. Recurvatum deformity can also develop in the knee secondary to contracture of the rectus femoris muscle. Progressive equinovalgus and equinovarus of the foot and ankle are associated with rocker-bottom deformity and subluxation of the talonavicular joint. Early recognition of progressive deformity in patients with cerebral palsy allows timely treatment and prevention of irreversible change.