Inguinal Canal Flashcards
What is the IC?
The inguinal canal is a short passage that extends inferiorly and medially through the inferior part of the abdominal wall.
Location of the IC
It is superior and parallel to the inguinal ligament, and between the deep and superficial inguinal rings
Why does the IC exist?
The canal serves as a pathway by which structures can pass from the abdominal wall to the external genitalia
What produced the IC?
The inguinal canal is the pathway by which the testes (in an individual with an XY karyotype) leave the abdominal cavity and enter the scrotum.
What is the gubernaculum?
A fibrous cord of tissue called the gubernaculum attaches the inferior portion of the gonad to the future scrotum or labia, and guides them during their descent
What is the length of the IC?
Adult - 4cm
Newborn - 0, rings are super-imposed
What is the fate of the gubernaculum in the adult?
The gubernaculum becomes two structures in the adult: the ovarian ligament and round ligament of uterus
Posterior wall of IC
Transversalis fascia
Conjoint tendon
Anterior wall of IC
Aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally.
Roof of IC
Transversus abdominis
Internal oblique
Transversalis fascia
Floor of IC
Inguinal ligament + lacunar ligament
Contents of the IC
Spermatic cord
Round ligament of uterus
Ilioinguinal nerve
Genital branch of the genitofemoral nerve
The journey of the round ligament of the uterus
It originates from the uterine horn and travels through the inguinal canal to attach at the labia majora.
Something worthy of note about the ilioinguinal nerve
It only travels through part of the inguinal canal, exiting via the superficial inguinal ring (it does not pass through the deep inguinal ring)
Nerve at most risk of damage during inguinal hernia repair
Ilioinguinal nerve
What is the pampiniform plexus?
A network of veins, responsible for the venous drainage of the testes. It has a unique configuration, wrapping itself around the testicular artery
Mid-inguinal point
Halfway between the pubic symphysis and the anterior superior iliac spine. The femoral pulse can be palpated here.
Midpoint of the inguinal ligament
Halfway between the pubic tubercle and the anterior superior iliac spine (the two attachments of the inguinal ligament). The opening to the inguinal canal is located just above this point.
Deep inguinal ring location
Found above the midpoint of the inguinal ligament, lateral to the epigastric vessels.
What forms the deep inguinal ring?
The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal.
Superficial ring location
The superficial (external) ring marks the end of the inguinal canal, and lies just superior to the pubic tubercle.
What forms the superficial inguinal ring?
It is a triangle shaped opening, formed by the evagination of the external oblique, which forms another covering of the inguinal canal contents.
What prevents the superficial ring from widening?
This opening contains intercrural fibres, which run perpendicular to the aponeurosis of the external oblique and prevent the ring from widening.
What is a hernia?
A hernia is defined as the protrusion of an organ or fascia through the wall of a cavity that normally contains it.
What is an indirect hernia?
The peritoneal sac enters the inguinal canal through the deep inguinal ring.
Cause of indirect hernia
They are caused by the failure of the processus vaginalis to regress.
Indirect hernia process
The peritoneal sac (and potentially loops of bowel) enters the inguinal canal via the deep inguinal ring. The degree to which the sac herniates depends on the amount of processus vaginalis still present. It can reach the scrotum
Cause of direct inguinal hernia
Direct inguinal hernias are acquired, usually in adulthood, due to weakening in the abdominal musculature.
Direct hernia process
The peritoneal sac bulges into the inguinal canal via the posterior wall medial to the epigastric vessels and can enter the superficial inguinal ring. The sac is not covered with the coverings of the contents of the canal.
Types of hernia based on the location of the epigastric vessels
Indirect - Lateral
Direct - Medial
Epigastric hernia
Between umbilicus and ASIS, caused by weakness in rectus sheath
Paraumbilical hernia
Congenital umbilical hernia causing protruding umbilicus
Incisional hernias
Occurs after surgery
Parts of a hernia
Neck, Body
Contents of a hernia
Omentum Coils of small intestine Appendix (right side) Sigmoid colon (left side) Part of urinary bladder Peritoneal fluid Caecum
What type of inguinal hernia is more painful?
Indirect, due to narrow neck and compromised blood supply. It can become incarcerated, unable to return or obstructed
