Anterior abdominal wall Flashcards
Layers of anterior abdominal wall
- Skin
- Subcut layer (fatty layer- camper’s fascia; membranous layer - scarpa’s fascia),
- Musculoaponeurotic layer:
- Sheath
- Encases rectus and pyramidal muscles - fuses at linea alba in midline and linea semilunaris on lateral border of rectus.
- Above arcuate line- anterior and posterior layers. Below- anterior only.
- anterior leaf = ext oblique and int oblique(split)
- posterior leaf = int oblique (split) and trans abdominins
- Muscles (pyramidalis muscle, rectus muscle, external oblique, internal oblique, transversus abdominus muscles)
- Transversalis fascia
- Pre-peritoneal fat
- Peritoneum
Where does the inferior epigastric enter the sheath?
Arcuate line
- at this level the inferior epigastric vessels enter the rectus sheath, travel superiorly and converge with superior epigastric vessels
Placement of lateral abdominal wall trochars to avoid vascular injury?
- 2/3 between umbilicus and ASIS
OR 2fingerbreadths superior and medial from ASIS - >8cm from the midline
- If visualising interior surface of lower anterior abdominal wall:
- Visualise medial umbilical fold (obliterated umbilical arteries), inferior epigastric lies lateral to this
- Placement of secondary ports: transilluminate the superficial epigastric and circumflex vessels, and identify their course prior to placing secondary trocars
https: //abdominalkey.com/basic-principles-and-anatomy-for-the-laparoscopic-surgeon/
Blood supply to anterior abdominal wall?
Skin/subcutaneous layer (branches from femoral artery):
- superficial epigastric artery
- external pudendal artery
- superficial circumflex iliac artery
Musculofascial layers (branches from external iliac artery):
- superior epigastric artery and inferior epigastric artery
- deep circumflex iliac artery
Nerve supply to anterior abdominal wall
T7-L1 nerve roots
Anterior branches of T7-T12 intercostal nerves,
Ilioinguinal (L1) and iliohypogastric (L1) nerves
Symptoms of injury to either ilioinguinal or iliohypogastric nerves?
sharp, burning, lancinating pain radiating from the incision to the suprapubic area, labia, or thigh, paraesthesia over these areas and pain relief after infiltration with a local anaesthetic
How to avoid nerve injury?
Laparotomy:
- Midline incision less likely (but carries other risks)
- A short transverse incision placed within the borders of the recti muscles and 3 cm above the symphysis pubis
- If it is necessary to extend the incision, curving it cephalad rather than continuing in a straight line
- Avoiding the use of cautery on the perforating branches of vessels helps avoid injury to the terminal sensory nerve fibres, which run alongside
During laparoscopy:
- Avoidance of port site incisions below the ASIS
Disadvantages of a midline incision
Watershed area- therefore poorly vascularised
Prone to dehiscence and infection
Longer healing time
Increased risk keloid and unsightly scarring as perpendicular to langers lines
Increased likelihood of hernia
Location of palmer’s point entry and indications
3 cms below the left costal margin along the mid-clavicular line
Indications:
- Previous surgery and concern re bowel adhesions
- Large uterine masses
- Umbilical hernia
- Suspected urachal abnormality
Advantages of a midline incision?
- Relatively avascular plane
- Little chance of nerve damage
- Provides excellent access to abdominal cavity - and can be easily extended if required
What are the landmarks of hesselbachs triangle?
What is its significance?
Triangle bordered by inguinal ligament, lateral border of rectus muscle, and inferior epigastric vessels.
This is where direct inguinal hernias occur.
describe the course of the inferior epigastric artery.
Branches from external iliac artery medical to the deep inguinal ring and courses superiorly on the posterior abdominal wall below transversals fascia, obliquely towards the umbilicus. It crosses the lateral border of the rectus muscle and courses between the rectus muscle and posterior leaf of rectus sheath (above arcuate line).
It anastomoses with superior epigastric vessel, a branch of internal thoracic artery.
What happens at the level of umbilicus?
All layers of the anterior abdominal wall fuse
L3/L4 vertebral level
T10 dermatome
Bifurcation of aorta
Iliac vessels join to form IVC
What are the 3 peritoneal folds/ligaments of the anterior abdominal wall?
What do they contain?
Median umbilical fold
- median umbilical ligament extending from the apex of bladder; a remnant of the urachus
Medial umbilical fold
-medial umbilical ligament; occluded part of the umbilical arteries
Lateral umbilical fold
-inferior epigastric arteries
What are the nerve roots of genitofemoral nerve?
Describe how it can be damaged during surgery and how this would present?
L1/L2
Pierces psoas major anteriorly and travels on its anterior surface in the retroperitoneum.
Genital branch - passes through inguinal canal to innervate scrotum (men) or mons and labia major (women).
Femoral branch - passes through femoral canal and innervates upper anterograde-medial thigh.
- Damaged by retractor placement
- During para-aortic lymphadenectomy
- During psoas hitch and ureteric reimplantation
Presentation:
- Anaesthesia of upper anteriomedial thigh, mons pubis and lateral labia majora
