Causes
A malfunctioning bladder sphincter, leading to retrograde ejaculation, may be a result either of:

Autonomic nervous system dysfunction. (Dysautonomia)
Operation on the prostate. It is a common complication of transurethral resection of the prostate, a procedure in which prostate tissue is removed, slice by slice, through a resectoscope passed along the urethra.It can also be caused by a retroperitoneal lymph node dissection for testicular cancer if nerve pathways to the bladder sphincter are damaged, with the resulting retrograde ejaculation being either temporary or permanent. Modern nerve-sparing techniques seek to reduce this risk; however, it may also occur as the result of Green Light Laser prostate surgery. Surgery on the bladder neck accounted for about ten percent of the cases of retrograde ejaculation or anejaculation reported in a literature review.Retrograde ejaculation is a common side effect of medications, such as tamsulosin, that are used to relax the muscles of the urinary tract, treating conditions such as benign prostatic hyperplasia. By relaxing the bladder sphincter muscle, the likelihood of retrograde ejaculation is increased. The medications that mostly cause it are antidepressant and antipsychotic medication, as well as NRIs such as atomoxetine; patients experiencing this phenomenon tend to quit the medications.Retrograde ejaculation can also be a complication of diabetes, especially in cases of diabetics with long term poor blood sugar control. This is due to neuropathy of the bladder sphincter. Post-pubertal males (aged 17 to 20 years) who experience repeated episodes of retrograde ejaculation are often diagnosed with urethral stricture disease shortly after the initial complaint arises.
Cavity may refer to:

Biology and healthcare
Body cavity, a fluid-filled space in many animals where organs typically develop
Gastrovascular cavity, the primary organ of digestion and circulation in cnidarians and flatworms
Dental cavity or tooth decay, damage to the structure of a tooth
Lung cavity, an air-filled space within the lung

Radio frequency resonance
Microwave cavity or RF cavity, a cavity resonator in the radio frequency range, for example used in particle accelerators
Optical cavity, the cavity resonator of a laser
Resonant cavity, a device designed to select for waves of particular wavelengths

Other uses
Cavity (band), a sludge metal band from Miami, Florida
Cavity method, a mathematical method  to solve some mean field type of models
Cavity wall, a wall consisting of two skins with a cavity

See also
Cavitation, the phenomenon of partial vacuums forming in fluid, for example, in propellers
Cavitary pneumonia, a type of pneumonia in which a hole is formed in the lung
Cavity Search (disambiguation)
Hollow (disambiguation)