TY - JOUR T1 - The bare essentials JF - Practical Neurology JO - Pract Neurol SP - 178 LP - 185 DO - 10.1136/jnnp.2010.213892 VL - 10 IS - 3 AU - Jalesh N Panicker AU - Clare J Fowler Y1 - 2010/06/01 UR - http://pn.bmj.com/content/10/3/178.abstract N2 - Neurogenic lower urinary tract dysfunction—the so-called neurogenic bladder—can result from many neurological conditions. The importance of this problem to patient health and quality of life is now better recognised, particularly as these days many of the symptoms can be treated. Optimal patient management requires an understanding of the physiology of the lower urinary tract, and its derangement in neurological disease. The lower urinary tract consists of the bladder and urethra and has just two roles: storage of urine and voiding at appropriate times. To regulate this, a complex neural control system acts like a switching circuit to maintain a reciprocal relationship between the reservoir (storage) function of the bladder and the continence (voiding) function of the urethra (figure 1). The pontine micturition centre is responsible for switching between the ‘storage’ phase and ‘voiding’ phase. It in turn receives input from other centres, particularly the periaqueductal grey of the midbrain, hypothalamus and cortical areas such as the prefrontal cortex. Figure 1 Innervation of the lower urinary tract. (A) Sympathetic fibres (blue) originate in the T11–L2 segments of the spinal cord and run through the inferior mesenteric ganglia (inferior mesenteric plexus, IMP) and the hypogastric nerve (HGN) or through the paravertebral chain to join the pelvic nerves at the base of the bladder and the urethra. Parasympathetic preganglionic fibres (green) arise from the S2–S4 spinal segments and travel in sacral roots and pelvic nerves (PEL) to ganglia in the pelvic plexus (PP) and in the bladder wall; this is where the postganglionic nerves that supply parasympathetic innervation to the bladder arise. Somatic motor nerves (yellow) that supply the striated muscles of the external urethral sphincter arise from S2–S4 motor neurons and pass through the pudendal nerves. L1, first lumbar root; S1, first sacral root; SHP, superior hypogastric plexus; SN, sciatic … ER -