Overview
The spermatic cord is a cord-like structure in males that connects the abdominal
cavity to the testes, via a channel known as the inguinal canal. The spermatic
cord contains various structures and is surrounded by three layers of fascia.
Gross Anatomy
Development
From 12
weeks of gestation onwards, the testes descends from the abdominal cavity and
into the scrotum. An invagination of the peritoneum (the processus vaginalis)
is found at the lower gubernaculum, and initiates the descent of the testes. As
the processus vaginalis lengthens it pulls fibres and fascia from the abdominal
wall, eventually forming the internal and external spermatic fascia and cremasteric
fascia of the spermatic cord.
Surface anatomy
Deep
(internal) inguinal ring: 2 cm superior to the mid-point of inguinal ligament,
which runs between the pubic tubercle and anterior superior iliac spine (ASIS).
Superficial
(external) inguinal ring: 1 cm superior and lateral to the pubic tubercle. The
spermatic cord terminates at the posteromedial border of the testes.
Macro-anatomy
The
structures contained within the spermatic cord are as follows:
- Arteries: Testicular, cremasteric and artery to
the vas
- Veins: Pampiniform plexus, cremasteric vein and
testicular vein
- Nerves: Genital branch of Genitofemoral nerve,
testicular nerves (sympathetic nerves) and the ilioinguinal nerve (runs
externally to the cord)
- Vas deferens
- Lymphatics (Drain into the para-aortic nodes at
L1/2 level)
- Processus vaginalis (extension of the peritoneum)
The
spermatic cord also contains three fascial planes:
- External spermatic fascia, originating from the
external oblique muscle
- Cremasteric fascia, which runs with the cremasteric
muscle), originating from the internal oblique and transversus abdominis
muscles
- Internal spermatic fascia, originating from the transversalis
fascia
Blood supply
The testicular
artery originates from the aorta at the level of L2 while the corresponding
testicular veins drain into the IVC on the right and the left renal vein on the
left. Both the artery and vein lie retroperitoneally on the psoas major. The cremasteric
vessels originate and drain into the inferior epigastric vessels. The artery of
the vas originates from the inferior vesicle artery, an anterior division of
the internal iliac artery.
Nerve supply
The genital
branch of Genitofemoral nerve originates from the L2 nerve root and contains
both motor (to the cremasteric muscle) and sensory components (innervation to
the scrotal skin, round ligament and labia majora). The sympathetic nerve
fibres carry pain sensation from the viscera to T9 & 10 dermatomes.
Clinical Anatomy
Testicular torsion: Twisting of the spermatic cord
around the axis of the testicle causes ischaemia, causing the rapid onset of
testicular pain. This is commonly due to inadequate fixation of the testicle to
the scrotum.
Varicocoele: This is caused by abnormally dilated veins
of the pampiniform plexus usually secondary to incompetent valves. It is
commonly left-sided due to the acute angle at which the testicular vein enters
the left renal vein and can cause male infertility. External compression of the
left renal vein can also cause the condition.
Quick Anatomy
Key Facts
Development |
The fascial layers of the spermatic cord are formed from the
abdominal wall musculature as the processus vaginalis lengthens towards the scrotum |
Blood
vessels |
Arteries: Testicular,
cremasteric and artery to the vas Veins: Pampiniform
plexus, cremasteric vein and testicular vein |
Nerves |
Genital
branch of Genitofemoral nerve, testicular nerves (sympathetic nerves) and the
ilioinguinal nerve (runs externally to the cord) |
Lymphatics |
Para-aortic
nodes at L1/2 level |
Aide-Memoire
The ‘rule of 3’s’ can be useful in order to remember the contents of the
spermatic cord: three fascial coverings, three arteries, three veins, three nerves
and others (lymphatics, processus vaginalis and vas deferens). It is important
to note that one of the nerves (ilioinguinal) runs externally to the spermatic
cord.
Summary
The
spermatic cord is a complex anatomical structure that contains vessels, nerves
and other structures. The tunica vaginalis is an extension of the peritoneum,
which forms the serosal covering of cord, and is a reminder of the
embryological origin of the cord from the abdominal cavity.
References
Drake,
Richard L et al. Gray's Anatomy For Students. Philadelphia: Elsevier/Churchill
Livingstone, 2005, p260-2
Shadbolt CL, Heinze SB,
Dietrich RB. Imaging of groin masses: inguinal anatomy and pathologic
conditions revisited. Radiographics. 2001;21 Spec No: S261-71.
Sadler,
T. W, and Jan Langman. Langman's Medical Embryology. Philadelphia:
Lippincott William & Wilkins, 2010, p253-5.