F- CLINICAL ASPECTS OF SPINAL CORD INJURIES
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priapism, while actually this is a result of a passive engorgement of the corpora cavernosa
due to the paralytic vasodilatation following the interruptions of the vasoconstrictor
fibres in the antero-lateral tracts of the spinal cord. Priapism—i.e. complete and
permanent erection—may occur in incomplete lesions in the acute stage if reflex function
is present.
Stage of reflex automatism
Once the stage of spinal shock has subsided, the erection reflex becomes one of the
components of the automatic functions of the isolated cord;, taking part in the 'mass
response' (Riddoch, 1917). In fact, it may appear, independent of cerebral participation,
before the reflex responses of the skeletal muscles are fully developed. Tactile stimuli of
varying type and intensity of the glans and around the penis, extending perineally or
to either side of the medial surface of the thigh, or even stroking of the sole of the feet
set up afferent impulses along the pudental nerves to the 2nd~4th sacral segment,
resulting in efferent responses, which run along the parasympathetic pathways causing
increased blood supply and distension of the corpora cavernosa and corpus spongiosum.
This will be associated with a reflex contraction of the bulbocavernosus, ischiocavernosus
and the transverse perineal muscles, which are involved in the ejaculation reflex. Once the
summation of afferent impulses during the process of erection is strong enough to elicit
contraction of the seminal vesicles, stimulation of the prostate gland and the ejaculatory
duct, resulting in ejaculation of the seminal fluid through the urethra is possible only
by an associated reflex contraction of the internal sphincter complex of the bladder,
which closes the bladder exit. Otherwise, as occurs following prostatectomy, the seminal
fluid is ejected into the bladder. From all this, it is obvious how much seminal ejaculation
in both complete and incomplete transections above the thoraco-lumbar junction depends
on the integrity of a co-ordinated reflex activity of the various stations of the copulatory
organs and how important it is to avoid their early local damage due to infection of the
bladder.
Complete lesions
Reflex erection leading to seminal ejaculation in complete transverse lesions above the
thoraco-lumbar junction, is rare; moreover, it also depends on the willingness and ability
of the female partner to adjust herself to the paraplegic's position. If ejaculation in com
plete lesions occurs, this is without orgastic sensation, but in lesions above T5—in
particular, cervical lesions—ejaculation is accompanied by stress phenomena of certain
autonomic mechanisms (autonomic hyperreflexia), such as rise of blood pressure, brady-
cardia, sweating in face and headache. The paraplegic's gratification following ejaculation
is certainly his pride in being able to satisfy the female partner. Moreover, successful
ejaculation is followed by relaxation of the spasticity of the skeletal muscles. But there
is no awareness of any somesthetic sensation of orgasm, especially in high lesions of the
spinal cord.
