Testis, Epididymis and Spermatic Cord: Gross Anatomy
References: (Benninghoff, 1993).
Gross Anatomy of the Testis
The testes are a paired organ in the scrotum, 4 × 3 × 2.5 cm, 20–25 ml volume. The testicles have a strong organ capsule (tunica albuginea testis). The testicular parenchyma is composed of 250–350 lobules, which drain through the mediastinum testis to the epididymis. The lobules are separated by connective tissue septa (Septula testis) originating from the mediastinum testis. A lobule of the testis consists of one or several seminiferous tubules, which end and start at therete testis.
Anatomy of the Epididymis
The epididymis is 5–10 mm thick and extends from the upper to the caudal pole of the testis. The epididymis can be divided in caput, corpus and cauda. A thin capsule and the serosa of the tunica vaginalis cover the epididymis.
8–10 efferent ducts transport the sperm from the rete testis into the ductus epididymidis. The epididymis consists mostly of the coiled epididymal duct, at the cauda of the epididymis the ductus deferens starts [fig. cross section of the testis and epididymis].
Anatomy of the Scrotum
The following structures enclose the contents of the scrotum, from outside to inside: scrotal skin, tunica dartos
, the tunica vaginalis testis lamina parietalis
provides the serous cavity for the testis (cavum serosum testis). The tunica vaginalis testis lamina visceralis
is the serous covering of the testicle. The testicular tissue is surrounded by the strong tunica albuginea
Residual structures of testicular development:
the appendix testis (hydatid of Morgagni)
and appendix epididymis
are remnants of testicular embryology (Müllerian duct), they are also called testicular appendages.
Spermatic Cord and Vascular Supply of the Testis
The vas deferens (ductus deferens) connects the epididymis with the urethra. Shortly before the prostate, the vas deferens enlarges and forms the Ampulla ductus deferens. The union of the vas deferens and the duct of the seminal vesicle forms the ejaculatory duct. The ejaculatory ducts pass through the prostate and empty at the Colliculus seminalis in the urethra.
Following structures accompany the ductus deferens from the abdomen to the testis in the spermatic cord [Fig. male external genitals].
Ductus deferens (vas deferens):
connects the epididymis to the urethra.
Arteries of the spermatic cord:
testicular artery (from the aorta), deferential artery (from the internal iliac artery), cremasteric artery (from the inferior epigastric artery).
Veins of the spermatic cord:
pampiniform plexus (venous plexus in the spermatic cord), forms the testicular vein and empties into the renal vein (left side) or vena cava (right side).
the lymphatic vessels of the testis drain via the spermatic cord to the paraaortic lymph nodes. Testicular tumours metastasize first to this lymph node station. The lymphatic vessels of the scrotum drain to the inguinal lymph nodes.
Nerves of the spermatic cord:
the autonomic nerve supply of testis originates from paraaortic ganglia. Main function is the sympathetic innervation of the testicular vessels.
Ramus genitalis from the genitofemoral nerve: originates from the lumbar plexus (L1–2) and passes through the inguinal canal. It supplies the scrotal skin, cremasteric muscle and tunica dartos.
Ilioinguinal nerve: originates from the lumbar plexus (L1) and supplies the scrotal skin, penis, groin and medial thigh.
Hull of the spermatic cord:
following structures enclose the contents of the spermatic cord, from outside to inside: scrotal skin, tunica dartos, external spermatic fascia, cremasteric muscle, internal spermatic fascia.
Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Benninghoff 1993 BENNINGHOFF, A.:
- Makroskopische Anatomie, Embryologie und Histologie des
München; Wien; Baltimore : Urban und Schwarzenberg, 1993