Define the inguinal canal, and summarise its content
An oblique intermuscular slit 6cm long above the medial aspect of the inguinal ligament (which runs from the ASIS to PT). Commences at the deep ring (halfway point) and ends at the superficial ring. Transmits the spermatic cord and ilioinguinal nerve.
What makes up the anterior wall of the canal?
EOM medially, and more laterally IOM. Their fibres run parallel to the lower border and diverge to make a v shaped opening. The medial crus runs to the pubic crest and the lateral crus run to the pubic tubercle. An intervening part has no attachment.
At the PT, fibres from the lateral crus pass upwards behind the medial crus to blend with the rectus sheath and those from the other side (=the posterior crus).
What strengthens the intervening section of anterior wall of the superficial inguinal ring that has no attachment?
The intercrural fibres running perpendicular and binding the crura.
What is a crus?
An elongated part of an anatomical structure, especially one that occurs as a pair
What constitutes the floor of the inguinal canal? Which way does the floor face?
The inrolled edge of the inguinal ligament, reinforced medially by the lacunar ligament.
The abdominal surface faces upwards and forwards. The femoral surface faces down and back.
What are the relations of the lacunar ligament?
The lacunar ligament rills the angle between the inguinal ligament and the pectineal line
What constitutes the roof of the inguinal canal?
The lower edges of IOM and TAM aponeuroses (conjoint tendon). The conjoint tendon arches in a concentric fashion to insert into PT and pectineal line.
The conjoint tendon and lacunar ligament lie in planes that are ….
…at right angles to one another
What supplies the lowermost fibres of IOM and TAM? What happens when the conjoint tendon contracts?
Ilioinguinal and iliohypogastric. The roof of the canal is lowered
What constitutes the posterior wall of the inguinal canal?
Conjoint tendon medially and weak TAM fascia laterally, covered by weak areolar tissue
On what does the integrity of the inguinal canal depend?
Anterior wall laterally and posterior wall medially
What is and what constitutes the interfoveolar ligament?
The interfoveolar ligament constitutes a functional medial edge to the deep ring and consists of TAM muscular fibres
Where does the deep ring lie?
Above the midpoint of the inguial ligament
What 5 landmark arterial branches and passages occur at the deep inguinal ring?
- The inferior epigastric artery crosses on the medial aspect of the deep inguianl ring, 2. giving off the cremaster branch, 3. and bounds the inguinal triangle.
- It also gives off the pubic branch which anastomoses with the obturator artery
- The ductus/round ligament exits the deep inguinal ligament lateral to the inferior epigastric and hooks around (?it)
What are the coverings of the spermatic cord and from whence are they derived?
- Internal spermatic fascia - investment derived from transversals fascia
- Cremasteric fascia and muscle - from IOM and TAM aponeurosis and muscles which spiral down the cord and return behind it to attach to the pubic tubercle. This can reflex elevate the testes
- Third covering is from the crura of the superficial ring (EOM)
List the six constituents of the spermatic cord
- Ductus deferens lower and posterior part of the cord
- Arteries: a) testicular, b) artery to ductus, c) cremasteric artery
- Veins: pampiniform plexus
- Lymphatics: a) deep to para-aortic and superficial from coverings to external iliac
- Nerves: a) genital branch of genitofemoral nerve, b) sympathetic twigs
- Processus vaginalis: obliterated remains of the peritoneal connection
Which nerve supplies the cremaster?