Pelvic Nerve Supply and Nursing Considerations

Nerve supply of the vulva and
perineum

    The pudendal nerve arises from the
second, third and fourth sacral nerves. As it passes along the outer wall of
the ischiorectal fossa, it gives off an inferior rectal branch and divides into
the perineal nerve and the dorsal nerve of the clitoris. The perineal nerve
gives the sensory supply to the vulva; it also innervates the anterior part of
the external anal sphincter and levatorani, and the superficial perineal
muscles. The dorsal nerve of the clitoris is sensory.

    Sensory fibers from the mons and
labia also pass, in the ilioinguinal and genitofemoral nerves, to the first
lumbar root. The posterior femoral cutaneous nerve carries sensation from the
perineum to the small sciatic nerve, and thus to the first, second and third
sacral nerves.The main nerve supply of the levatorani muscles comes from the
third and fourth sacral nerves.

Nerve supply of the pelvic viscera

    To describe what can be seen
dissection of the extensive autonomic nerve supply of the pelvic organs is one
thing to determine the physiological functions of the various parts of the
system is another.

    Nerve fibers of the pre-aortic
plexus of the sympathetic nervous system are continuous with those of the
superior hypogastric plexes, which lies in front of the last lumbar vertebra
and is wrongly called the pre sacral nerve. Below, the superior hypogastric
plexus divides, and on each side its fibers are continuous with films passing
beside the rectum hi join the uterovaginal plexus inferior hypogastric plexus Plexus
of Frankenhauser). 

    This plexus lies in the loose cellular to posterolateral to
the cervix below the uterosacral folds of peritoneum

    Parasympathetic fibers from the
second, third and fourth sacral nerves join the uterovaginal plexus Fibers from
(or to) the bladder, uterus, vagina and rectum join the plexus. The
uterovaginal plexus.contains a few ganglion cells, so it is likely that a few
motor nerves have their relay stations there and then pass onwards with the
blood vessels to the viscera       

    The ovary is not innervated by the
nerves already described but from the ovarian plexus, which sur rounds the
ovarian vessels and joins the pre-aortic plexes high up.

    This description thus avoided any
conjecture as to the particular function of the sympathetic and parasympathetic
nerves, and no opinion has been expressed as to whether the various nerves
carry senssory or motor impulses Clinical facts are few. It is evident that
afferent sensory impulses are often carried in the superior hypogastric plexus.
If this is divided during presacral neurectomy, pain from the bladder and
uterus can often be blocked. 

    Apart from a transient pelvic hyperaemia, there is
no change in the motor fanction of either bladder or uterus. At an ordinary by
sterectomy, the uterinvaginal plexus is not disturbed, but after a more
extensive Wertheim operation, there may be painless atony and distension of the
bladder, which is attributes to loss of bladder sensation because the sacral
connections of the uterovaginal plexus have been divided

    The motor effects are even less
certain than the sensory: Stimulation of the cut lower end of the hypogastric
plexus seems to have no effect on the bladder the uterus Although it has boot
stated that the parasympathetic nerves are excitatory to the musculature of the
body of the uterus and inhibitory to that of the cervix, and that the
sympathetic nerves have the opposite effect, there is not general agreement
about this.

    The myometrium contains both a and ẞ
adrenergic receptors and also cholinergic receptors. In the non-pregnant
uterus, the balance of their action is uncertain, but during pregnancy, strong
stimulation of B-receptors with B-mimetic drugs such as isoxsuprine will
inhibit myometrial activity.

Anatomical Description of other
related Structure Genital Systems 

The nephrogenic card develops from
the mesoderm and forms the urogenital ridge and the mesonephric duct. The
paramesonephric duct, which later forms the Mullenan system, is the precursor
of female genital development

The lower ends of the Müllerian
ducts come together in the midline, fuse and develop into uterus and cervix

Most of the upper vagina is of
Müllerian origin. The lower vagina forms from the sinovaginal bulbs.

The primitive gonad is first evident
at 5 weeks of embryonic life and forms on the medial aspect of the mesonephric
ridge. The size and ratio of the cervix to uterus change with age and parity.

Vaginal pH is normally acidic and
has a protective role for decreasing the growth of pathogenic organisms

An adult uterus weighs about 70g and
consists of three layers: the peritoneum, the myometrium and the endometrium

The cervix is narrower than the body
of the uterus and is approximately 2.5 cm in length. The ureter runs about 1 cm
lateral to the supravaginal cervix

The epithelium of the cervix in its
lower third is stratified squamous epithelium and the junction between this and
the columnar epithelium is where most cervical carcinoma arises.

The ovary is the only
intraperitoneal structure not covered by peritoneum

The main supports to the pelvic floor
are the connective tissue and levatorani muscles. The main supports of the
uterus are the uterosacral ligaments, which are condensations of connective
tissue.

The ovarian arteries rise from the
aorta. The right ovarian vein drains into the vena cava, the left ovarian vein
usually drains into the left renal vein.

The major nerve supply of the pelvis
comes from the pudendal nerves, which arise from the second, third and fourth
sacral nerves.