Penis (Penis)
Anatomically, the penis is divided into three main parts:
- Root (radix penis) — the fixed part.
- Body (corpus penis) — the main free part.
- Glans (glans penis) — the distal expansion.
The basis of the organ consists of three erectile structures. The paired corpora cavernosa (corpora cavernosa penis) are surrounded by their own dense tunica albuginea of the corpora cavernosa. Below them lies the unpaired corpus spongiosum (corpus spongiosum penis), the main feature of which is that the male urethra (urethra masculina) runs directly through its thickness.
Scrotum (Scrotum)
The scrotum is a specialized musculocutaneous pouch. Inside it lie the testes, epididymides, and the lower parts of the spermatic cords. The internal space of the scrotum is divided into two halves by a special septum — septum scroti.
Tunics of the scrotum (from superficial to deep):
- Skin.
- Dartos fascia (tunica dartos).
- External spermatic fascia (fascia spermatica externa).
- Cremasteric fascia.
- Cremaster muscle (m. cremaster).
- Internal spermatic fascia (fascia spermatica interna).
- Tunica vaginalis testis.
Bulbourethral glands (Glandulae bulbourethrales)
These are paired glandular structures located directly within the urogenital diaphragm.
The excretory ducts of these glands course anteriorly and open into the spongy part of the urethra. The main function of the bulbourethral glands is the secretion of a specific mucous fluid.
Blood supply and innervation
Arterial blood supply to the structures is provided by branches of the internal pudendal artery (a. pudenda interna), testicular artery (a. testicularis), and other vessels. Venous blood drains through a dense network — the pampiniform plexus (plexus pampiniformis).
Innervation of the external genitalia is provided by branches of the hypogastric plexus (plexus hypogastricus) and the pudendal nerve (n. pudendus).
Briefly: answers to topical questions
What arteries supply blood to the male external genitalia?
The blood supply to the male external genitalia is provided by branches of the internal pudendal artery, external pudendal artery, and testicular artery. For the scrotum, the cremasteric artery (a. cremasterica) is also indicated.
What nerves innervate the male external genitalia?
Innervation of the male external genitalia is provided by branches of the pudendal, lumbar, sacral, and hypogastric plexuses. The ilioinguinal nerve (n. ilioinguinalis) innervates the skin of the scrotum. The intermediate branch of the posterior femoral cutaneous nerve participates in innervating the skin of the perineum.
What forms the dartos fascia of the scrotum?
The dartos fascia of the scrotum (tunica dartos) is formed by subcutaneous tissue devoid of fat, containing smooth myocytes. It is located beneath the skin and constitutes the second layer of the scrotal and testicular tunics.
To easily remember the main erectile bodies of the penis, keep the "two plus one" rule in mind: TWO corpora cavernosa (for rigidity, enclosed in a tunica albuginea) and ONE corpus spongiosum (to transmit the urethra).
Class and exam questions
Where exactly do the ducts of the bulbourethral glands open?
The ducts of these glands open into the spongy part of the male urethra.
What is located inside the corpus spongiosum of the penis?
The male urethra (urethra masculina) runs within the substance of the corpus spongiosum (corpus spongiosum penis).
What structures does the scrotum house?
The scrotum contains the testes, epididymides, and the lower sections of the spermatic cords.
What else to study on this topic
- Topography and branching of the internal pudendal artery
- Structure and functions of the pampiniform plexus
- Histological structure of the tunica albuginea of the corpora cavernosa
- Anatomy of the urogenital diaphragm
- Course and segments of the male urethra
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