Achilleo-calcaneal-plantar complex: reality or virtuality?

Abstract

due to insufficient description of its myology, particularly the deep muscles. In the present study a detailed description of the deep muscles of the lower leg is given, based on micro-dissection and, in situ, by imaging techniques. Membrana interossea cruris covers the anterior surface of musculus interosseus cruris, extended between tibia and fibula. Distally it proceeds as a relatively strong interosseous ligament. Musculus interosseus cruris consists of several bundles, interconnecting tibia and fibula. Musculus pronator profundus is located posterior to m. interosseus cruris. Its superior fibres are directed from caput fibulae to corpus tibiae, resembling the condition of m. popliteus in higher mammals. Direction of the inferior bundles of m. pronator profundus coincides approximately with the direction of the crus. They are inserted in a vertical tendon at the level of the tibial and fibular epiphyses. This tendon is continuous with the meniscoid crossing ligaments of the fibulotalar joint. Distally, transverse muscle bundles overly this tendon superficially. It is likely that all of these deep muscles are involved in rotation mechanisms during locomotion. Their positions within the flexor compartment of the lower leg suggest pronator functions in particular. Coapting effects on tibia and fibula may be expected. P5 Descending afferent projections to the m-region in the cat The M(= medial)-region, also called pontine mic-turition center or Barrington's nucleus in the dorsolateral pontine tegmentum controls micturi-tion. Its axons terminate in the sacral intermediolateral cell group (IML) and the dorsal intermediomedial cell group (IMM) of the sacral spinal cord. The IML contains preganglionic para-sympathetic motoneurons that innervate the bladder, and the IMM contains GABA-and glycinergic neurons that inhibit urethral sphincter motoneurons. Stimulation in the M-region results in micturition. In order to find out which brain regions have direct control of micturition, the present study attempted to determine which regions in mes-, di-and telencephalon send fibers to the M-region. In five female cats WGA-HRP injections were made in the area of the dorsolateral pontine tegmentum including the M-region. The sacral spinal cord and brain were cut into serial transverse sections. In all cases anterogradely labeled fibers were found in the IML and IMM. Retrogradely labeled neurons were found in the dorsal, lateral and ventrolateral periaqueductal gray (PAG), ventromedial hypothalamus, medial preoptic area (MPO), bed nucleus of the stria terminalis, central nucleus of the amygdala, infra-limbic cortex and prelimbic cortex. To verify whether these areas indeed project to the M-region or to adjacent structures, [ 3 H]leucine and WGA-HRP injections were made in those regions in which retrogradely labeled neurons were found. Results show that only the ventrolateral and dorsal PAG and the MPO project to the M-region and have direct control of micturition. All other parts of the limbic system that have been shown to influence micturition must have indirect projections to the M-region via PAG or MPO. P6 Achilleo-calcaneal-plantar complex: reality or virtuality?