1.Anatomy of inguinal canal Flashcards
DEFINITION of inguinal canal
It is an oblique passage in the lower part of the anterior abdominal wall, through which the testis passes in order to leave the abdomen and reach the scrotum.
LENGTH of inguinal canal
1.5 inch
4 cm
DIRECTION of inguinal canal
passes downward, forward and medially from deep to superficial ring
SITE of inguinal canal
It lies parallel to the medial half of the inguinal ligament.
BEGINNING of inguinal canal
DEEP ( INTERNAL) INGUINAL RING
DEEP ( INTERNAL) INGUINAL RING
Definition
Site
Boundaries
Definition of DEEP ( INTERNAL) INGUINAL RING
It’s an oval opening “vertical longitudinal axis” in the fascia transversalis
Site of DEEP ( INTERNAL) INGUINAL RING
- 1/2 inch above the mid point of inguinal ligament
* just lateral to the inferior epigastric artery.
Boundaries of DEEP ( INTERNAL) INGUINAL RING
- Above and lateral Boundaries
* Below and medial Boundaries
- Above and lateral Boundaries of DEEP ( INTERNAL) INGUINAL RING
The arched lower margin of fascia transversalis.
Below and medial Boundaries of DEEP ( INTERNAL) INGUINAL RING
The inferior epigastric vessels
END of inguinal canal
SUPERFICIAL (EXTERNAL) INGUINAL RING
SUPERFICIAL (EXTERNAL) INGUINAL RING
- Definition
- Site
- Attachements
Definition of SUPERFICIAL (EXTERNAL) INGUINAL RING
Triangle opening in external oblique aponeurosis
Site of SUPERFICIAL (EXTERNAL) INGUINAL RING
1/2 inch above and medial to the pubic tubercle
Attachements of SUPERFICIAL (EXTERNAL) INGUINAL RING
- The medial “superior” crus
* The lateral “inferior” crus
The medial “superior” crus in Attachements of SUPERFICIAL (EXTERNAL) INGUINAL RING
attached to the front of symphysis pubis
The lateral “inferior” crus in Attachements of SUPERFICIAL (EXTERNAL) INGUINAL RING
- Stronger
* Inserted into the pubic tubercle
Boundaries of the inguinal canal
- ANTERIOR WALL
- POSTERIOR WALL
- ROOF
- FLOOR
ANTERIOR WALL Boundaries of the inguinal canal
1- External oblique aponeurosis along its whole length.
2- Strengthened laterally by fleshy fibres of internal oblique muscle originating from the lateral 1/2 of the inguinal ligament.
POSTERIOR WALL Boundaries of the inguinal canal
- Fascia transversalis along its whole length.
- Conjoint tendon (also known as inguinal falx) along its medial 1/2
- Reflected part of inguinal ligament along its medial 1/4
Alternative name for Conjoint tendon in POSTERIOR WALL Boundaries of the inguinal canal
inguinal falx
composition Conjoint tendon in POSTERIOR WALL Boundaries of the inguinal canal
Arched fibers of Internal oblique muscle and transversus abdominis
ROOF Boundaries of the inguinal canal
Arched fibres of conjoint muscle
FLOOR Boundaries of the inguinal canal
Upper grooved surface of medial 1/2 of inguinal ligament
Inguinal ligament
Definition
Attachments
Definition of Inguinal ligament
It’s the lower free border of external oblique aponeurosis
Attachments of Inguinal ligament
attached to pubic tubercle medially and ASIS laterally
CONTENTS OF THE Inguinal CANAL
(A) Ilio-inguinal nerve (L1)
(B) Spermatic cord :
Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
Origin
Course
Sensory supply
Motor supply
Origin of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
The ilioinguinal nerve is a branch of the lumbar plexus which lies within the substance of the psoas major muscle.
Course of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
Ascending to the iliac crest
Piercing the transversus abdominis
Entering the inguinal canal
Leaving the inguinal canal
Ascending to the iliac crest in Course of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- It emerges from the lateral border of the psoas major just below the iliohypogastric nerve,
- passes obliquely across the quadratus lumborum and iliacus.
Piercing the transversus abdominis in Course of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- Above the iliac crest, the ilioinguinal nerve pierces the transversus abdominis
- passes in the plane between the transversus abdominis and the internal oblique muscle.
Entering the inguinal canal in Course of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- It enters the inguinal canal by piercing the internal oblique muscle
- The nerve lies in front of the cord
- once the nerve enters the canal, it becomes only sensory
Leaving the inguinal canal in Course of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- It leaves the canal through the superficial inguinal ring
Sensory supply of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- The skin of the inguinal region
- Upper medial part of the thigh
- Anterior 1/3 of the scrotum (or labia majora)
- Root of the penis.
Motor supply of Ilio-inguinal nerve in CONTENTS OF THE Inguinal CANAL
- Shares in the motor supply to the internal oblique, transversus abdominis
- Gives the main motor supply to the conjoint tendon before entering the canal
Spermatic cord in CONTENTS OF THE Inguinal CANAL
Alternative structure in female
Coverings
Contents
Alternative structure in female for Spermatic cord in CONTENTS OF THE Inguinal CANAL
Round ligament of the uterus in females
Coverings of Spermatic cord in CONTENTS OF THE Inguinal CANAL
- Internal spermatic fascia
- Cremasteric muscle and fascia:
- External spermatic fascia:
Origin of Internal spermatic fascia in Coverings of Spermatic cord in CONTENTS OF THE Inguinal CANAL
From transversalis fascia at deep inguinal ring
Origin of Cremasteric muscle and fascia in Coverings of Spermatic cord in CONTENTS OF THE Inguinal CANAL
From internal oblique muscle.
Origin of External spermatic fascia in Coverings of Spermatic cord in CONTENTS OF THE Inguinal CANAL
From external oblique aponeurosis at the superficial inguinal ring.
Contents of Spermatic cord in CONTENTS OF THE Inguinal CANAL
- Ordinary classification of contents
* Classification of contents according to their position in the cord
Ordinary classification of contents of Spermatic cord in CONTENTS OF THE Inguinal CANAL
4 Vessels
2 Nerves
2 Structures
4 Vessels in Ordinary classification of contents of Spermatic cord in CONTENTS OF THE Inguinal CANAL
- Testicular artery & Pampiniform plexus of veins.
- Artery of the vas & vein of the vas
- Cremasteric artery & vein
- Lymphatic vessels.
origin of Artery of the vas
branch of inferior vesical artery
origin of Cremasteric artery
branch of inferior epigastric artery
2 Nerves in Ordinary classification of contents of Spermatic cord in CONTENTS OF THE Inguinal CANAL
- Sympathetic nerve fibres along the testicular artey.
2. Cremasteric nerve
Alternative name for Cremasteric nerve
genital branch of genito-femoral nerve
2 Structures in Ordinary classification of contents of Spermatic cord in CONTENTS OF THE Inguinal CANAL ( 2 V)
- Vas deferens.
2. Vestige of processus vaginalis.
Classification of contents of spermatic cord according to their position in the cord
(A) Anterior contents:
(B) Posterior contents :
(C) Contents within the coverings of the cord:
Anterior contents of spermatic cord
- Pampiniform plexus.
* Lymphatic vessels.
Posterior contents of spermatic cord
- Testicular artery with sympathetic fibers along it
* Vas deferens and its vessels.
Contents within the coverings of the spermatic cord
Cremasteric nerve and vessels.
THE PROTECTIVE MECHANISMS OF THE CANAL
- The obliquity of the canal ( The flap valve mechanism):
- The shutter mechanism of the internal oblique muscle
3- The ball valve mechanism
4- The slit valve mechanism
- Attachment of the superior crus of the internal ring to the transversus abdominis by facial slips
Most important PROTECTIVE MECHANISMS OF THE CANAL
- The obliquity of the canal
2. The shutter mechanism of the internal oblique muscle
The obliquity of the canal in THE PROTECTIVE MECHANISMS OF THE CANAL
- Alternative name
- Mechanism
- Note on the mechanism
Alternative name of The obliquity of the canal in THE PROTECTIVE MECHANISMS OF THE CANAL
The flap valve mechanism
Mechanism of The obliquity of the canal in THE PROTECTIVE MECHANISMS OF THE CANAL
The internal and external rings do not lie opposite to each other
Therefore when the intra abdominal pressure rises the ant. & post. walls of the canal are approximated thus obliterating the passage.
Note on the mechanism of The obliquity of the canal in THE PROTECTIVE MECHANISMS OF THE CANAL
This mechanism is absent in infants below 2 years
The shutter mechanism of the internal oblique muscle in THE PROTECTIVE MECHANISMS OF THE CANAL
On straining, the lower arched fibres of the int. oblique muscle contracts approximating the roof to the floor like a shutter.
The ball valve mechanism in THE PROTECTIVE MECHANISMS OF THE CANAL
Contraction of the cremasteric muscle helps
both inguinal rings.
The slit valve mechanism in THE PROTECTIVE MECHANISMS OF THE CANAL
Contraction of the ext. oblique m. approximates the 2 crura of the superficial ring thus narrowing it.
Attachment of the superior crus of the internal ring to the transversus abdominis by facial slips in THE PROTECTIVE MECHANISMS OF THE CANAL
so that contraction of the transversus abdominis draws the internal ring laterally increasing the obliquity of the canal