Sem 1 - I - Inguinal Canal & Scrotum - Deep/superficial inguinal rings, borders of canal,ligaments, hernia, spermatic cord Flashcards
The inguinal canal is an oblique passage passing through the lower part of the anterior abdominal wall How long is the inguinal canal in an adult? What does the inguinal canal carry in males and females?
In an adult, the inguinal canal is approx 4 cm * In males - it carries structures to and from the testis as well as the ilioinguinal nerve * In females - it carries the round ligament of the uterus from pelvis to labia majora as well as the ilioinguinal nerve It is a lot easier to see the inguinal canal in males as the spermatic cord travels through it which is much large than the round ligament of the uterus
What are the two nerves carried within the inguinal canal? Which does not pass through the deep inguinal ring?
The ilioinguinal nerve (only passes through superficial inguinal ring) and the genital branch of the genitofemoral nerve
What does the genital branch of the genitofemoral nerve supply?
Genital branch of genitfemoral nerve in men - motor innervation to the cremaster muscle and sensory to the scrotum In women - sensory to the mons pubis/labia majora
The inguinal canal has two entries/exits, the superficial and deep inguinal ring What shape is the superficial inguinal ring? What is it formed by?
The superficial inguinal ring despite its name is actually triangular and it is formed by a defect in the external oblique aponeurosis
The edges of the superficial inguinal ring are known as margins (crura), what do these crura give rise to?
In males, these margins give rise to external spermatic fascia which will go on to cover the spermatic cord
Even though the round ligament exits the superficial inguinal ring in females, why may it still be difficult to locate?
The round ligament becomes fibrous and therefore may blend with the coverings of the inguinal canal
What is the opening of the inguinal canal into the body wall known as? The superifical inguinal ring is said to be triangular shaped, what is the shape of this opening?
The opening of the inguinal canal into the body wall is the deep inguinal ring and it is said to be oval shaped
Where is the opening of the deep inguinal ring and through which tissue?
The oval opening is midway between the anterior superior iliac spine (ASIS) and pubic symphysis about 1.3cm above the inguinal ligament It is a defect in the transversalis fascia
Superficial inguinal ring – superficial opening – external oblique- triangle Deep inguinal ring – deep opening – transversalis fascia – oval What lies medially to the deep inguinal ring? What fascia does the deep inguinal ring give origin to?
Medially to the deep inguinal ring are the inferior epigastric vessels The deep inguinal ring crura gives origin to the internal spermatic fascia Can see the vas deferens, genital branch of genitofemoral nerve and testicular vessels joining to form the spermatic cord
What is the inferior rolled edge of the external oblique aponeurosis better known as? it forms part of the floor of the inguinal canal
This would be the inguinal ligament
The inguinal canal has different borders Roof (superior) Anterior Floor (inferior) Posterior What forms the different borders of the inguinal canal? (MALT - 2Ms, 2As, 2Ls, 2Ts)
- Roof (superior) border - formed by the fibres from the
- * internal oblique Muscles and
- * transversus abdominus
- Muscles Anterior border - formed by fibres from the
- * external oblique Aponeurosis and
- * plus internal oblique aponeurosis in lateral third
- Floor (inferior) border - formed by
- * inguinal Ligament
- * Lacunar Ligament medially
- Posterior border -
- * transversalis fascia
- * Conjoint Tendon in medial third
State again what the borders of the inguinal canal are?
- Superior or roof - fibres from the internal oblique and transversus abdominus Muscles
- Anterior - Aponeurosis of external oblique and internal oblique in the lateral 1/3rd
- Inferior or floor - (inferior rolled edge of the external oblique) inguinal Ligament and the Lacunar Ligament medially
- Posterior - Transversalis fascia and conjoint Tendon in the medial 1/3rd
What is the conjoint tendon?
This is the common insertion of the internal oblique and transversus abdominus into the pubic crest and pectineal line
How is the inguinal ligament formed? What extends from the medial end of the inguinal ligament?
The inguinal ligament is formed by the inferior edge of the external oblique aponeurosis rolling back on itself From the medial aspect of the ligament extends the lacunar ligament which attaches the inguinal ligament to the pectineal ligament (along the pectineal line)
The lacunar ligament forms the medial aspect of the inferior border of the inguinal canal What does it form the medial border of?
The lacunar ligament forms the medial border of the femoral ring (where intestine can herniate through) - the femoral ring and sheath are within the femoral triangle
The oblique passage, the inguinal canal, is a weak area in the abdominal wall and therefore when there is an increase in pressure in the abdomen, we want to flatten this canal to prevent any herniation When there is an increase in abdominal pressure ge cough, the abdominal wall muscles contract. Which of the muscles will flatten the inguinal canal?
When there is an increase in abdominal pressure it is the roof of the inguinal canal that will flatten the canal -this is the fibres of the internal oblique and transversus abdominus muscles
A hernia is a protrusion of tissue What percentage of abdominal hernias are inguinal hernias? Where are inguinal hernias in relation to the pubic tubercle?
75% of abdominal hernias are inguinal Inguinal hernias are supero-medial in relation to the pubic tubercle
There are direct and indirect inguinal hernias What is the difference in how they arise? Where do they lie in relation to the inferior epigastric vessels?
An indirect inguinal hernia enters the inguinal canal via a congenital weakness in the deep inguinal ring - therefore it is lateral to the inferior epigastric vessels A direct inguinal hernia pushes three a weak spot in the back of the inguinal canal and is therefore medial to the inferior epigastric vessels
The spermatic cord is a collection of structures which passes to and from the testis What forms the internal spermatic fascia? What forms the external spermatic fascia?
The internal spermatic fascia is formed from the margins of the transversalis fascia The external spermatic fascia is formed from the margins of the external oblique aponeurosis
Where does the spermatic cord begin and end? What structures are contained within the spermatic cord?
The spermatic cord begins at the deep inguinal ring lateral to the inferior epigastric vessels and ends at the posterior aspect of the testis It contains: * Vas deferens * Testicular artery * Pampniniform plexus of veins * Genital branch of gentiofemoral nerve * Cremasteric artery and artery of vas deferens * Lymph vessels and autonomic nerves
Initially testis are inside body cavity and the body creates a pathway out to where the scrotum will be in the male or where the labia majora will be in the female The coverings of the spermatic cord consist of 3 concentric layers of fascia from the anterior abdominal wall The spermatic cord starts from a peritoneal diverticulum known as what?
The spermatic cord starts from a peritoneal diverticulum known as the processus vaginalis
The processus vaginalis begins at L1 and passes through the abdominal wall acquiring a tubular sheath from each layer to make up the spermatic cord Which layer of the abdominal wall does not provide a tubular sheath when passed through?
This would be the transversus abdominus muscle
Describe how the peritoneal diverticulum, the processus vaginalis, becomes to be the spermatic cord (in females it becomes the round ligament of the uterus)?
* The processus vaginalis passes through the deep inguinal ring (the transversalis fascia) giving the INTERNAL SPERMATIC FASCIA * It then passes under the transversus abdominus which does not give a tubular sheath layer * The processus vaginalis passes through the internal oblique muscle giving the CREMASTER MUSCLE * Finally the processus vagnialis passes through the external oblique aponeurosus giving the EXTERNAL SPERMATIC FASCIA
State again the contents of the spermatic cord
* Vas deferenes * Testicular artery * Testicular vein - begins as pampiniform plexus of veins * Lymph vessels * Autonomic nerves * Cremasteric artery * Artery of the vas deferens * Genital branch of genitofemoral nerve
* Vas deferenes - where does it run? * Testicular artery - where does it branch from? * Testicular vein - begins as pampiniform plexus of veins - where do they drain? * Lymph vessels - where does the lymph drain? * Autonomic nerves * Cremasteric artery - branch of what? * Artery of the vas deferens - branch of what? * Genital branch of genitofemoral nerve - motor to what?
Vas deferens is a muscular duct transporting spermatozoa from epididymis to urethra Testicular artery branches at L2 from abdominal aorta Left testicular vein drains to left renal vein, right drains to IVC Lymph from testis drains to para-aortic nodes Cremasteric artery - branch of inferior epigastric artery Artery of the vas deferens - branch of inferior vesical artery Genital branch - innervates cremaster muscle
The scrotum is an outpouching of skin from the abdominal wall The superficial fascia of the scrotum is continuous with the abdominal wall, what is the name of the abdominal wall superficial fascia? They join to make the dartos muscle (Fascia)
This would be Camper’s fascia which loses its fatty content to fuse with Scarpa’s fascia to form the dartos superficial fascia of the scrotum
What is the function of the cremaster muscle? What is its arterial and nerve supply?
Cremaster muscle - functions to raise the testes and scrotum upwards for warmth and protection when it contracts Arterial supply - cremasteric artery from inferior epigastric artery and genital branch of genitofemoral nerve from L1,2 lumbar plexus
What is the remnant of the processus vaginalis which is now a closed off serous membrane enclosing the testi?
This would be the tunica vaginalis
Embryology Mesenchyme cells condense to form gubernaculum through inguinal canal to labio-scrotal swelling What then happens in the males and females?
The testis follow the same path as the gubernaculum through the inguinal canal at the 7/8th month and therefore have the same coverings as the gubenaculum In females, the gubernaculum is stuck to the uteris so the ovaries stay in the pelvis but the round ligament of the uterus passes through the inguinal canal
The testis create sperm and a tough fibrous capsule surrounds the testis Where in the testis is sperm produced? What is the tough fibrous capsule known as?
Sperm is produced in the seminiferous tubules of the testis The tough fibrous capsule surrounding the testis is the tunica albunginea
Where do the seminferous tubules drain sperm to? What temperature is the tesits in comparison to the abdomen to allow it to produce sperm? Where is sperm stored before it is entered into the vas deferens?
Seminiferous tubules drain sperm into the rete testis which drain into the head of the epididymis via efferent ductules where it is stored before it enters the vas deferens at its inferior pole The temp in the testis is 3 degrees lower in the abdomen
Where is the lymphatic drainage of the testis? Where is the lymphatic drainage of the scrotal wall and fascia?
Lymphatic drainage of the testis and epididymis is to the paraaortic nodes at the root of the testicular artery Lymphatic drainage of the scrotal walls and fascia is to the superficial inguinal nodes
