Anterior abdominal wall Flashcards
What are the 9 regions of the abdomen?
- Left/right hypochondrium
- Epigastric
- Left/right lumbar
- Umbilical
- Left/right iliac fossa
- Suprapubic
What are the 2 longitudinal planes dividing the abdomen?
Mid-clavicular lines
What are the 2 transverse planes dividing the abdomen ?
- Subcostal plane (L2)
- Intertubercular plane (L4)
On slim individual, where does the umbilicus lie?
Opposite L3 vertebrae
What are the 2 layers of fascia overlying the anterior abdominal wall?
- Camper’s fascia (superficial): Fatty layer which is continuous with dartos fascia of scrotum in men.
- Scarpa’s fascia (deep): Membranous layer which is continuous with superficial perineal (Colles’) fascia.
What structures are located in the transpyloric plane?
Spinal:
- L1 vertebrae
- End of spinal cord
Vascular:
- Origin of the SMA
- Origin of hepatic portal vein
Visceral:
- Hila of the kidneys
- Pylorus of the stomach
- Neck of the pancreas
- Duodenojejunal flexure
- Fundus of gallbladder
Bony:
- Tip of 9th costal cartilage
Which muscles are found in the anterior abdominal wall?
- External oblique
- Internal oblique
- Transversus abdominis
- Rectus abdominis
What are the origins and insertions of external oblique?
Origin: Lower 8 ribs.
Insertions:
- ASIS and pubic tubercle (via inguinal ligament).
- Linea alba (forms anterior rectus sheath).
What is the innervation and function of the external oblique?
Innervation: (T7-12)
Functions:
- Compression of abdomen
- Flexion of trunk
- Bending of trunk
What are the origins and insertions of the internal oblique?
Origins:
- Thoracolumbar fascia
- Anterior 2/3 iliac crest
- Lateral 2/3 inguinal ligament
Insertions:
- Linea alba (via rectus sheath)
- Pubic crest
What is the innervation and function of the internal oblique?
Innervation:
- Lower 6 intercostal nerves (T7 – 12)
- L1 (ilioinguinal nerve)
Functions:
- Compression of abdomen
- Flexion of trunk
- Bending of trunk
What are the origins and insertions of the transversus abdominis?
Origins:
- Lower 6 costal cartilages
- Thoracolumbar fascia
- Anterior 2/3 iliac crest
- Lateral 1/2 inguinal ligament
Insertions:
- Linea alba (via posterior rectus sheath)
- Pubic crest (via conjoint tendon)
What is the innervation and function of the transversus abdomins?
Innervation:
- Lower 6 intercostal nerves (T7 – 12)
- L1 (ilioinguinal nerve)
Functions:
- Compression of the abdomen
What are the origins and insertions of the rectus abdominis?
Origins:
- Medial head (tendinous): Pubic symphysis
- Lateral head (muscular): Pubic crest
Insertions:
- 5th - 7th costal cartilages
What is the innervation and function of the rectus abdominis?
Innervation:
- T7-12
Functions:
- Compression of abdomen
- Flexion of vertebral column
- Accessory muscle of expiration
Which muscles form the conjoint tendon?
- Internal oblique
- Transversus abdominis
What is the roof and floor of the inguinal canal?
Roof: Conjoint tendon
Floor: Inguinal and lacunar ligament
What is the anterior and posterior walls of the inguinal canal?
Anterior:
- External oblique aponeurosis
- Inguinal ligament (at origin of internal oblique) Posterior:
- Medial: Conjoint tendon
- Lateral: Transversalis fascia
What is the roof and floor of the inguinal canal?
Roof: Conjoint tendon
Floor: Inguinal and lacunar ligament
What are the attachments of the inguinal ligament?
- Anterior superior iliac spine (ASIS)
- Pubic tubercle
What are the relations of the inguinal rings?
- Deep inguinal ring: Midline of the inguinal ligament
- Superficial inguinal ring: Medial to the inferior epigastric artery
What is the structure of the rectus sheath?
- In the upper abdomen, the aponeuronsis of the internal oblique divides into 2 layers, one anterior and one posterior to the rectus abdominis, forming rectus sheath.
- The aponeurosis of the external oblique fuses with the anterior layer.
- The aponeurosis of the internal oblique fuses with the posterior layer.
- 3-4 cm below umbilicus, aponeurosis of all 3 muscles become anterior to rectus abdominis.
- Free edge of the posterior rectus sheath is called the arcuate line.
What is the blood supply of the rectus abdominis?
- Superior epigastric artery
- Inferior epigastric artery (from external iliac artery and anastomoses with superior epigastric)
- Runs on posterior surface of rectus abdominis and anterior to posterior rectus sheath (above arcuate line)
- Runs medial to deep inguinal ring
What are the locationsof the 3 transverse tendinous intersections of the rectus abdominis?
- Xephisternum
- Between xephisternum and umbilicus
- At umbilicus
What is the location of the subcostal neurovascular bundle?
Between internal oblique and transversus abdominis
What are the contents of the inguinal canal?
- Females: Round ligament
- Males: Spermatic cord
What are the contents of the spermatic cord?
Arteries:
- Testicular artery
- Artery to the vas deferens
- Cremasteric artery
Veins:
- Pampiniform plexus
Nerves:
- Genitofemoral nerve (genital branch)
- Testicular nerve
- Ilioinguinal nerve (outside cord laterally)
Other structures:
- Vas deferens
- Lymphatics
- Tunica vaginalis
What is the lymphatic drainiage of the anterior abdominal wall?
- Above umbilicus: Pectoral nodes (axillary nodes)
- Below umbilicus: Superficial inguinal nodes
Where is McBurney’s point?
- Base of appendix
- 1/3 along line from ASIS to umbilicus
What are the types of abdominal incisions?
- Longitudinal incisions (e.g. midline, paramedian)
- Muscle-splitting incisions
- Subcostal incisions
- Suprapubic incisions
What are the criteria for selecting type of incision?
- Adequate exposure
- Access to desired organs
- Minimising injury to muscles
- Minimising wound healing time
What is the linea semilunaris?
Lateral border of rectus abdominis
What is responsible for the ‘six pack’?
Tendinous intersections between rectus abdominis and the external oblique aponeurosis.
