Trunk Muscles
Eve K. Boyle, Vondel S. E. Mahon, Rui Diogo in Handbook of Muscle Variations and Anomalies in Humans, 2022
The external urethral sphincter varies in presentation between males and females (Jung et al. 2012; Standring 2016). In males, the fibers inferior to the prostate compose the external sphincter of the membranous urethra (Jung et al. 2012). The muscle fibers originate from the junction of the inferior pubic rami and ischium (Jung et al. 2012). In females, the urethral sphincter is found at the distal end of the bladder and is referred to as a urogenital sphincter that has three components (Jung et al. 2012). The urogenital sphincter contains (1) the true sphincter that surrounds the urethra, (2) a compressor urethral muscle that arises from the ischiopubic ramus and passes anterior to the urethra below sphincter urethrae, and (3) the urethrovaginal sphincter, a muscle below compressor urethrae that extends from the ventral and lateral walls of the urethra to the vagina, up to the vestibular bulb (Oelrich 1983; Jung et al. 2012; Standring 2016).
Female Methods
Sujoy K. Guba in Bioengineering in Reproductive Medicine, 2020
On account of the convenience, surface electrodes were the first to be tried. One of the important applications is the assessment of urethral sphincter activity. A variety of approaches have been adopted and they do not quantify equally all the muscles involved. Both the muscles of the anal sphincter and the urethral sphincter receive innervation from the S2-S4 spinal segments. This similarity led to the premise that monitoring of anal sphincter EMG is a good approach to urethral sphincter activity. Anal plug electrodes (Figure 11.10) have two active ring electrodes and the indifferent electrode is taped to the thigh. A catheter placed within the electrode carrier allows monitoring of the rectal pressure. In recent controlled investigations where the anal plug EMG is compared with urethral sphincter EMG obtained with indwelling electrode it is seen that the relationship between the two EMGs is quite variable. This is so because the levator ani, external anal sphincter, and urethral sphincter muscles can all contract independently. This finding limits the significance attached to anal EMG in urologic studies. Another electrode system tried was placed around an urethral catheter. Even this approach leaves doubt whether the potential pickup is from the striated rhabdosphincter, periurethral muscle or smooth urethral muscles.
Urogynaecology and pelvic floor problems
Helen Bickerstaff, Louise C Kenny in Gynaecology, 2017
A fine pressure catheter is placed in the bladder through the urethra and a second catheter in the rectum, and the bladder is filled with warm saline while pressure recordings are made with the patient sitting on a commode that records leakage (Figure 10.4A). The pressure generated by any contraction of the detrusor can be inferred by subtraction (bladder pressure − abdominal pressure = detrusor pressure). During filling the patient is asked to declare the onset of bladder filling sensation (usually around 150 ml volume), a strong desire to void (around 350 ml and the onset of urgency (up to 500 ml, depending on bladder capacity) (Figure 10.4B). When urgency is reported (and functional bladder capacity is reached) filling is stopped and the patient performs various actions to provoke leakage and/or detrusor contractions (e.g. coughing, star jumps, listening to running water), before voiding while the pressure catheters remain in place. A urodynamic test will provide evidence of urethral sphincter weakness (Figure 10.4B) or DO (Figure 10.4C), as well as identifying normal or abnormal voiding function.
Managing autonomic dysfunction in Parkinson’s disease: a review of emerging drugs
Published in Expert Opinion on Emerging Drugs, 2020
Dinkar Kulshreshtha, Jacky Ganguly, Mandar Jog
The primary function of urinary bladder is the storage and voiding of urine. This is facilitated by a synchronization between detrusor muscle and urethral sphincter, which in turn is related to the neuronal networks in the spinal cord and brain. The detrusor muscle and the internal urethral sphincter are supplied by the sympathetic and parasympathetic nervous system and are under involuntary control while the external urethral sphincter is under voluntary control and supplied by the pudendal nerve. While sympathetic stimulation causes detrusor relaxation and urethral sphincter contraction and aids storage, parasympathetic stimulation has the opposite effect and causes voiding [13]. Fifty-five to eighty percent of PD patients complain of bladder dysfunction at some point in time. Both storage (urinary urgency, frequency, nocturia, with or without incontinence) and voiding (slow and/or interrupted stream, terminal dribble, hesitancy and straining) symptoms occur in PD [14]. Nocturia, a common symptom in PD may be due to nocturnal polyuria, characterized by increased nocturnal urine production of more than 20–33% of the entire 24-h volume [15]. Reduced bladder capacity, poor compliance and detrusor overactivity (DO) have been shown in urodynamic studies [16]. The proposed mechanism for overactive bladder (OAB) symptoms in PD is disruption of the dopamine D1-GABAergic direct pathway and its GABAergic collateral to the micturition circuit, resulting in loss of inhibition of the micturition reflex and OAB symptoms [17–19].
The clinical pharmacology of the medical treatment for overactive bladder in adults
Published in Expert Review of Clinical Pharmacology, 2020
Hadi Mostafaei, Shahrokh F. Shariat, Hanieh Salehi-Pourmehr, Florian Janisch, Keiichiro Mori, Fahad Quhal, Sakineh Hajebrahimi
Neural circuits in the brain and spinal cord control normal micturition. They coordinate the activity of the smooth muscles in the detrusor and urethra as well as the striated muscles of urethral sphincter and pelvic floor [21]. An integrated afferent and efferent neuronal complex of peripheral neural circuits including sympathetic, parasympathetic, and somatic neurons innervate the lower urinary tract [22]. In the bladder fullness, stimulation of stretch-sensitive receptors activates mechanosensitive axons. They transfer impulses of bladder fulling to the brain, and thus, bladder contraction is initiated by these sensory stimuli [23]. The bladder afferent pathway is comprised of two types of nerve fibers, Aδ- and C-fibers. Aδ-fibers are mechanosensitive with myelinated axons, whereas C-fibers are insensitive to bladder distension and have unmyelinated axons. Non-nociceptive and nociceptive intravesical pressures activate Aδ-fibers but thermal changes and/or chemical irritation of bladder mucosa activate C-fibers [24].
Characteristics of urodynamic study parameters associated with intermediate-term continence after robot-assisted radical prostatectomy in elderly patients
Published in The Aging Male, 2020
Keiko Iguchi, Tomoaki Tanaka, Akinori Minami, Katsuyuki Kuratsukuri, Junji Uchida, Tatsuya Nakatani
At 5–7 days prior to surgery and 3 months after surgery, a urodynamic study was carried out on each patient by three urologists (TT, AM, and KI). This study involved filling cystometry, a pressure-flow study, an electromyogram of the external urethral sphincter, and urethral pressure profile using the Helix Urodynamics Systems (ANDOROMEDA®, Germany). We measured the urethral pressure profile using an 8-french two-channel urethral catheter. The catheter was withdrawn at a speed of 0.5 cm per minute. An 8-french two-channel urethral catheter was inserted for filling and intravesical pressure recording. A 9-french rectal balloon catheter was inserted for abdominal pressure recording. The bladder was filled with room-temperature saline at the rate of 50 ml per minute. According to the standard criteria mentioned in a published report [13], we measured the first sensation, maximum cystometric capacity, detrusor overactivity (DO), maximum flow rate (Qmax), detrusor pressure at Qmax (Pdet Qmax), maximum urethral closure pressure (MUCP), and functional length of the urethra (FLU). The definition of DO was basically derived from the International Continence Society report on the terminology for adult male lower urinary tract and pelvic floor symptoms and dysfunctions; DO is defined as the occurrence of detrusor contractions during filling cystometry. These contractions, which may be spontaneous or provoked, produce a wave form on the cystometrogram, of variable duration and amplitude. These contractions may be phasic or terminal [13,14].
Related Knowledge Centers
- Bladder
- Detrusor Muscle
- Muscle
- Pudendal Nerve
- Urine
- Urethra
- External Sphincter Muscle of Male Urethra
- External Sphincter Muscle of Female Urethra
- Internal Urethral Sphincter
- Ischiopubic Ramus