Impotence A Puzzle To Be Solved
NATIONAL JOURNAL OF HOMOEOPATHY 1996 Jul / Aug Vol V No 4.
Mukund Karambelkar.
Impotence is a very delicate yet complex topic for a practitioner. Although a lot of passions are involved around the sexual life of human being, this topic is poorly understood and requires thorough education of the patient. An attempt has been made here to resolve the mysteries regarding impotence. First let us define certain terms to clear the confusion.
Impotence--This term indicates that a man cannot have erections and hence fails to carry out his sexual function.
Ejaculation--This term indicates emission of semen from penis in pulsatile manner and the end of the act of coitus resulting in a flaccid state of penis.
Premature Ejaculation--This term indicates that a man can have erection but gets an ejaculation before he can introduce his penis into the vagina.
Male fertility--This term indicates poor quality of the semen resulting in inability of the man to impregnate a woman.
A potent man having a good sex life may be infertile while an impotent man can produce good semen which can impregnate his wife with artificial insemination.
Physiology of a Penile Erection--The penis consists of Corpus Cavernosum; two spongy paired cylinders contained in a thick envelope, the tunica albuginea, and Corpus Spongiosum and glans with very thin tunica. In both the structures, within the tunica are numerous sinusoids among the interwoven trabaculae of the smooth muscles and supporting connective tissue that harbour the terminal cavernous nerves and arterioles. The paired internal pudendal artery is the main source of blood supply to the penis while venous drainage is through multiple small veins to dorsal vein and then internal pudendal vein.
The nerve supply of the penis plays an important role in erection. The penis is innervated by two sets of nerves; Autonomic nervous system (sympathetic and parasympathetic) and somatic nerves (sensory and motor). From the neurons in the spinal cord and peripheral ganglia, the sympathetic and parasympathetic nerves merge to form the cavernous nerves and these nerves are responsible for neurovascular events during erection and detumescence. The somatic nerves are responsible for sensation of penis and contraction of the bulbocavernous and ischiocavernous muscles.
The parasympathetic supply comes from 2, 3 and 4 sacral spinal cord segments which is responsible for tumescence (erection) while sympathetic supply comes from thoracic 11 to lumbar 2 spinal segment which is responsible for detumescence (ejaculation). The sensory pathways go via dorsal nerve of penis to internal pudendal nerve to dorsal roots of 2nd to 4th nerves of spinal cord and spinothalamic tract to the thalamus and sensory cortex of brain. Onus nucleus is the centre of somatomotor penile innervation. These nerves travel in the sacral nerves to the pudendal nerves to innervate bulbocavernous and ischiocavernous muscles.
The contraction of the ischiocavernosus muscle causes rigid erection phase while rhythmic contractions of the bulbocavernous muscles expels the semen down the narrowed urethral lumen and results in external ejaculation from the meatus.
The spinal erection centres are located at intermedilateral column of the sacral cord and sends processes in to the areas of laminae 5 and 7 and the dorsal commissure. In the brain medial preoptic area (MPOA) is the important integration centre for sexual drive and penile erection.
According to nature of stimulus there are three types of erections.
- Reflexogenic Erection: This erection is provided by tactile stimulus to the genitalia and is mediated through lower spinal centres.
- Psychogenic Erection: This erection originates from audio-visual impulses and fantasies and signals are mediated through brain to spinal centres.
- Nocturnal Erection: This type of erection occurs during REM sleep through unknown mechanism.
