The seminal vesicles (also known as the vesicular or seminal glands) are a pair of glands found in the male pelvis, which function to produce many of the constituent ingredients of semen. They ultimately provide around 70% of the total volume of semen, and in this article, we will consider the anatomical relations, functions, neurovascular relations and clinical significance of the seminal vesicles.
Perhaps their most important anatomical relation is with the vas deferens, which combine with the duct of the seminal vesicles to form the ejaculatory duct, which subsequently drains into the prostatic urethra. Internally the gland has a honeycombed, lobulated structure with a mucosa lined by pseudostratified columnar epithelium. These columnar cells are highly influenced by testosterone, growing taller with higher levels, and are responsible for the production of seminal secretions.
The seminal glands, along with the Ejaculatory ducts, Epididymis and Ductus (vas) deferens, are derived from the mesonephric ducts, the precursor structure of male internal genitalia. These structures can easily be remembered using the acronym SEED.
The secretions of the seminal gland have a key role in the normal functioning of semen, making up 70% of its total volume. It is notable however that the first fractions of expelled semen contain mainly spermatozoa and prostatic secretions; the fluids from the seminal vesicles are included in the late ejaculate fractions. These fluids contain:
The remaining volume of semen is made up of testicular spermatozoa, prostatic secretions and mucus from the bulbourethral gland.
The arteries to the seminal gland are derived from the inferior vesicle, internal pudendal and middle rectal arteries, all of which stem from the internal iliac artery. The innervation of the gland, like much of the male internal genitalia, is mainly sympathetic in origin. You can use the classic memory aid Point and Shoot to remember this - erection, or pointing, receives parasympathetic innervation, while ejaculation (including contraction of the smooth muscle of the seminal vesicles) receives sympathetic innervation.
The lymphatic drainage of the gland is the external and internal iliac lymph nodes.
Inflammation of the seminal vesicles (also known as vesiculitis or spermatocystitis) may result from microbial infection of the urethra and prostate gland. Symptoms such as vague perineal or penile pain, discomfort during ejaculation and haemospermia (blood in the ejaculate) are suggestive of such infection. Treatment consists of proper antibiotic regimens. In rare cases, obstruction of the seminal vesicle duct may lead to abscess formation. In such cases paracentesis is the mainstay of treatment. Drainage of these abscesses may be facilitated by transrectal ultrasound (TRUS) guided aspiration.
Physical examination of the seminal glands through digital rectal examination (DRE) is difficult. Therefore, it is important that other diagnostic techniques are used to help confirm the diagnosis, such as imaging studies (e.g. ultrasound, CT, and MRI) to assess for the presence of infection or inflammation. Laboratory tests, such as semen analysis and culture, can also help to identify the presence any infection or underlying condition.
Seminal vesiculitis is a serious condition which can lead to significant complications, such as infertility or sterility. Therefore, it is important that any suspected infection is addressed and treated as soon as possible to prevent further progression and the development of any serious or long-term consequences.
The seminal vesicles are paired organs of the male reproductive system, located at the base of the bladder. They are part of the ejaculatory ducts system and produce a moderate amount of the components of semen. Anatomically, the seminal vesicles are located above the prostate gland and posterior to the urinary bladder. They are elongated and slightly flattened and have a shape similar to that of an almond. Their structure is made of a mucous membrane, with several folds and pouches.
Their most important anatomical relation is with the vas deferens, which combine with the duct of the seminal vesicles to form the ejaculatory duct, which subsequently drains into the prostatic urethra. Internally the gland has a honeycombed, lobulated structure with a mucosa lined by pseudostratified columnar epithelium. These columnar cells are highly influenced by testosterone, growing taller with higher levels, and are responsible for the production of seminal secretions.
The Seminal glands, along with the Ejaculatory ducts, Epididymis and Ductus (vas) deferens, are derived from the mesonephric ducts, the precursor structure of male internal genitalia. These structures can easily be remembered using the acronym SEED.
The secretions of the seminal gland have a key role in the normal functioning of semen, making up 70% of its total volume. It is notable however that the first fractions of expelled semen contain mainly spermatozoa and prostatic secretions; the fluids from the seminal vesicles are included in the late ejaculate fractions. These fluids contain a number of elements:
The remaining volume of semen is made up of testicular spermatozoa, prostatic secretions and mucus from the bulbourethral gland.
The arteries to the seminal gland are derived from the inferior vesicle, internal pudendal and middle rectal arteries, all of which stem from the internal iliac artery.
The innervation of the gland, like much of the male internal genitalia, is mainly sympathetic in origin. You can use the classic memory aid Point and Shoot to remember this: Erection, or pointing, receives parasympathetic innervation, while ejaculation (including contraction of the smooth muscle of the seminal vesicles) receives sympathetic innervation.
The lymphatic drainage of the gland is the external and internal iliac lymph nodes.
Clinically, seminal gland abscess may form due to an untreated bacterial infection, and it is usually diagnosed using imaging techniques. During an examination, the practitioner will palpate the area around the seminal vesicles to assess for any abnormal nodularity or tenderness.
Overall, the seminal vesicles serve an important role in the male reproductive system. Embryologically, they stem from the mesonephric ducts and are responsible for producing a moderate amount of semen components. Functionally, they secrete about 50–70% of the total seminal fluid volume and contribute nutrients such as fructose, citric acid, and phosphorylation enzymes to support the spermatozoa's survival in the female reproductive tract. As for the vasculature, the seminal vesicles are supplied with blood by means of the superior and inferior vesicle arteries. Regarding the innervation of the seminal vesicles, they are mainly supplied by the autonomic nervous system, through the inferior hypogastric plexus (sympathetic) and the pelvic splanchnic nerves (parasympathetic). Lymphatic drainage from the seminal vesicles follows a similar path as that of the blood supply.
