6 Abdominal wall, inguinal region and hernias 1 Flashcards
What structures are beneath the 4 quadrants of the abdomen?
- RUQ: Liver and gall bladder
- RLQ: Ileum, caecum, appendix
- LUQ: Jejunum
- LLQ: Sigmoid colon
Which 2 lines are used to determine the 4 quadrants of the abdomen? And where do they lie or pass through?
- Transumbilical plane - lies at the level of the umbilicus corresponding to the L3/4 intervertebral disc
- Median plane -
passes through the xiphoid process & pubic symphysis
Which 4 lines are used to determine the 9 regions of the abdomen? And where do they lie or pass through?
- Midclavicular Lines (2)
- passes through midpoint of clavicle - Subcostal Plane -
lies at L3 vertebra level uniting the lowest point of the costal margins - level of the 10th CCs - Transtubercular/ intertubercular plane -
lies at the level of the L5 vertebra uniting the two iliac tubercles
What is the umbilicus?
A scar representing the site of attachment of the umbilical cord in the foetus
How is the superficial fascia of the abdominal wall divided?
- Superficial fatty layer - Camper’s fascia
2. Deep membranous layer - Scarpa’s fascia
What is fascia?
- “Packing tissue” allowing movement of structures in relation to each other but without being restrictive
- Some provides muscle attachment
What is the composition of the internal fascia in the abdominal wall?
- There are very thin, negligible layers of fascia between the muscles
- Deep to the muscles (but outside the peritoneum), there is a layer of endo-abdominal or transversalis fascia
- Variable extraperitoneal fascia which is immediately external to the peritoneum
What are the 2 layers of the superficial fascia/ subcutaneous tissue of the perineum?
- Superficial fatty layer -Camper’s fascia
2. Deep membranous layer - Colles’/perineal fascia
What are Scarpa’s fascia and Camper’s fascia continuous with in the perineum?
• Scarpa’s fascia is continuous with Colles’/perineal fascia
• Camper’s fascia is continuous with the superficial fatty layer of the
superficial fascia/subcutaneous tissue of the perineum
In the abdomen, what fascia layers are found deep to the muscle layer?
- Transversalis fascia
2. Extraperitoneal fascia
Where does thoracolumbar fascia pass from and to? What does it give origins to? What may be at risk?
Passes from the iliac crest –> 12th rib in 3 layers (anterior, middle & posterior) that surround the back muscles & fuse together to give origin to the transversus abdominis & internal oblique muscles but not external oblique (free edge posteriorly - lumbar hernia)
What does transversus abdomens and internal oblique arise from?
Thoracolumbar fascia
What is transversals fascia (undo-abdominal fascia)?
Thin layer of fascia (connective tissue)
• lines the transversus abdominis muscle
• continuous with a similar layer lining the diaphragm & the iliacus muscle
What is extraperitoneal fascia?
Thin layer of fascia (connective tissue)
• contains a variable amount of fat
• lies between the transversalis fascia & the parietal peritoneum
What lines the walls of the abdomen?
Parietal peritoneum -
thin serous membrane that encloses peritoneal cavity
What are the layers in the abdomen?
- Skin
- Superficial fascia:
• Fatty layer (Camper’s)
• Membranous layer (Scarpa’s) - External oblique m
- Internal oblique m
- Transversus abdominis m
- Transversals fascia
- Exztraperitoneal fascia
- Parietal peritoneum
What are the anterior abdominal wall muscles? (4)
3 broad, thin sheets (sup to deep): 1. External oblique 2. Internal oblique 3. Transversum abdominis
A vertical muscle:
4. Rectus Abdominis (and Pyramidalis)
What are the functions of the anterior abdominal wall muscles?
- Support abdominal contents and raise intra-abdominal pressure, withstanding pressure from descent of the diaphragm
- Support vertebral column, flexing, laterally flexing and rotating the trunk against resistance
- Respiration
What 2 points are on the same coronal plane on a pelvis?
- Anterior superior iliac spine
2. Pubic tubercle
Where does the arcuate line continue from?
Pectineal line
External oblique:
Attachments?
Fibre direction?
Nerve supply?
- Attachments:
• Lower 8 ribs
• Lateral lip of iliac crest • Aponeurosis to linea alba via rectus sheath
• Forms the inguinal ligament - Fibre direction:
• Downwards and medially - Nerve supply:
• T7-12
What is the inguinal ligament? What is it’s attachments?
Continues as?
- Inrolled, inferior edge of external oblique
- From ASIS to pubic tubercle
- Continues as lacunar and pectineal ligaments
What is the superficial ring?
Triangular opening in external oblique aponeurosis with its base at the pubic crest
Internal oblique:
Attachments?
Fibre direction?
Nerve supply?
- Attachments
• Thoracolumbar fascia
• Iliac crest (inside external oblique)
• Lateral 2/3rds of inguinal ligament
• Lower 3 or 4 ribs & costal cartilages
• Aponeurosis to linea alba (xiphoid to pubic
symphysis) via rectus sheath
• Pubic crest behind the superficial inguinal
ring via conjoint tendon (with transversus abdominis) - Fibre direction:
• Upwards & medially to ribs, but downwards to conjoint tendon - Nerve supply:
• T7 to T12 plus L1 via the iliohypogastric nerve
to the fibres that form the conjoint tendon
What is the consequence of injury to the iliohypogastric nerve?
- May weaken the conjoint tendon
* Predispose to inguinal hernias
Transversus abdominis:
Attachments?
Fibre direction?
Nerve supply?
- Attachments
• Thoracolumbar fascia
• Iliac crest (inside internal oblique)
• Lateral 1/3rd or 1/2th of inguinal ligament
• Lower 6 ribs & costal cartilages
• Aponeurosis to linea alba (xiphoid to pubic
symphysis) via rectus sheath
• Pubic crest behind the superficial inguinal
ring via conjoint tendon (with internal
oblique) - Fibre direction:
• Transversely to ribs, linea alba &
conjoint tendon - Nerve supply:
• T7 to T12 plus L1 via the iliohypogastric nerve
to the fibres that form the conjoint tendon
What is the conjoint tendon formed from? Attachements?
- Formed from the aponeuroses of internal oblique & transversus abdominis
- Attaches to the pubic crest & pectineal line behind the superficial inguinal ring therefore supports the ring
Rectus abdominis:
Attachments?
Fibre direction?
Nerve supply?
1. Attachments • Costal cartilages of ribs 5 to 7 • Xiphoid process • Pubic symphysis • Pubic crest (behind the conjoint tendon & superficial inguinal ring) • Pectineal line
- Fibre direction:
• Vertically but interspersed with tendinous intersections - Nerve supply:
• T7 to T12
What is pyramidalis?
Small triangle anterior to rectus abdominis from the pubic crest to linea alba
What forms the rectus sheath?
- Each rectus abdominis is enclosed anteriorly & posteriorly between the bilaminar aponeuroses of the external oblique, internal oblique & transversus abdominis that form the rectus sheath
- In the midline they fuse as the linea alba (relatively avascular: good for entering the abdomen, but poor healing!)
What happens to the rectus sheath and inferior epigastric vessels at the arcuate line and below?
- All the aponeuroses pass anteriorly & the posterior sheath ends
- Inferior epigastric vessels enter behind rectus abdominis
Inguinal canal: What is it? Created by? Openings? Contains?
- Oblique passage, (4 to 6cm long) through the anterior abdominal wall connecting the abdominal cavity to the scrotum in males or the labia majora in females
- “Tunnel” created by the descent of the testis “pushing” through the 3 layers of muscle
- The inguinal canal has two openings:
(1) Deep inguinal ring
(2) Superficial inguinal ring
• Each “protected” by 2 of the 3 muscles (or aponeuroses)
4. Contents: • Vas/ductus deferens in males • Testicular artery in males • Round ligament of uterus in females • Genital branch of genitofemoral nerve (L1/2) • Ilioinguinal nerve (L1)
Superficial inguinal ring:
Location?
Structural features?
- Triangular opening in the external oblique aponeurosis with its base at the pubic crest
- Medial & lateral (stronger) crura
- Supported from behind by the conjoint tendon (combined tendons of internal oblique & transversus abdominis)
Deep inguinal ring: What is it? Overlain by? Transmits which structures? Position?
- Opening in or evagination of transversalis fascia
2.Overlain (anteriorly) by:
• Internal oblique
• External oblique
- Transmits:
• Vas/ductus deferens
• Gonadal vessels (in spermatic cord) - Lies lateral to the inferior epigastric vessels about 1cm above the mid-point of the inguinal ligament (midway between the ASIS & pubic tubercle/ midway between the ASIS & pubic symphysis -mid-inguinal point)
What are the inguinal canal boundaries?
- Anterior:
• External oblique
• Internal oblique laterally - Posterior:
• Conjoint tendon medially
• Transversalis fascia laterally - Roof:
• Arching fibres of internal oblique and
• Transversus abdominis - Floor:
• In rolled lower edge of external oblique (inguinal ligament)
• Strengthened medially by lacunar ligament
What are the mechanics of hernias?
- On coughing & straining (e.g. micturition, defecation & parturition)
• The arching lowest fibres of the internal oblique & transversus
abdominis muscles contract flattening out the arched roof of the
inguinal canal so that it is lowered toward the floor
• The roof may actually compress the contents of the inguinal canal
against the floor so that the canal is virtually closed - When great straining efforts may be necessary (e.g. defecation & parturition)
• The person naturally tends to assume the squatting position
• The hip joints are flexed & the anterior surfaces of the thighs are
brought up against the anterior abdominal wall
• By this means the lower part of the anterior abdominal wall is
protected by the thighs
In males, what is most susceptible to the development of hernias?
Inguinal region
What is a hernia?
Protrusion of a viscus through the wall of its containing cavity
What is the normal location of an inguinal and femoral hernia?
- Inguinal hernia -above & medial to the pubic tubercle
* Femoral hernia - passes through the femoral canal & appears below & lateral to the pubic tubercle
What is a direct inguinal hernia?
- Through the posterior wall of the inguinal canal medial to the inferior epigastric vessels
- Not covered by layers of spermatic fascia
What is an indirect inguinal hernia?
- Through the deep inguinal ring (persistent processus vaginalis) lateral to the inferior epigastric vessels (usually congenital or pre-adolescent but can be any age)
- Maybe in the processus vaginalis & within the coverings of the spermatic cord
- Bowel in the spermatic cord, covered by parietal peritoneum, passing through the deep inguinal ring of transversalis fascia & therefore covered by internal, cremasteric & external spermatic fascia passing lateral to the inferior epigastric vessels
What is Hesselbach’s/ Inguinal triangle?
• Direct inguinal
hernias
• Usually a piece of
fat or small bowel from inside the peritoneal cavity, therefore covered by parietal peritoneum, pushing against a weakened conjoint tendon (usually in mature adult male)
What forms the internal spermatic fascia at deep inguinal ring?
Transversalis fascia
What forms the external spermatic fascia?
External oblique
Which type of inguinal hernia is not covered by layers of the spermatic fascia?
Direct inguinal hernia
What occurs in more advanced direct inguinal hernia?
- Pushing ahead of the peritoneum, transversalis fascia & combined transversus abdominis with internal oblique (conjoint tendon) & through the superficial inguinal ring (in external oblique & extending as external spermatic fascia) to enter the scrotum
- Ends up in scrotum, parallel to spermatic cord & with its own coverings of peritoneum, transversalis fascia, conjoint tendon & external oblique as external spermatic fascia having passed medial to the inferior epigastric vessels
Where is cremasteric fascia from?
Transversus abdominis and internal oblique
When will hernias increase in size?
On coughing or straining
When do hernias reduce in size or disappears?
When relaxed or supine
How will a hernia that causes obstruction present?
- Colicky abdominal pain, distension & vomiting may occur)
- It will be tense, tender & irreducible
How will a hernia that causes strangulation present?
Lump will become red & tender
