Anatomy of Obs and Gynae Surgical Incisions Flashcards
List the two most common surgical incisions in O+G and their anatomical locations
Lower segment C-section (suprapubic, ‘bikini line’)
Laparoscopy (vertical midline incision)
Which anatomical lines are used to determine location of incision and layers incised?
Langer’s lines
List the layers of the anterolateral abdominal wall from superficial to deep
Skin Superficial fascia External oblique Internal oblique Transverse abdominus Rectus sheath Rectus abdominus
What is the linea alba?
Midline blending of aponeuroses
What is an aponeurosis?
Flat sheet or ribbon of tendon-like material that anchors a muscle or connects it with the part that the muscle moves
List the attachments of external oblique
Lower ribs (5-11)
Iliac crest
Pubic tubercle
Linea alba
Describe the orientation of fibres of external oblique
‘Hands in pockets’
Same direction as external intercostals - inferomedial
List the attachments of internal oblique
Lower ribs (912)
Thoracolumbar fascia (posterior)
Iliac crest
Linea alba
Describe the orientation of fibres of internal oblique
‘Hands in chest’
Same direction as internal intercostals - inferolateral
List the attachments of transverse abdominus
Lower ribs
Thoracolumbar fascia
Iliac crest
Linea alba
Describe the orientation of fibres of transverse abdominus
‘Corset muscle’
Transverse!
What structures divide each rectus abdominus into 3 or 4 smaller muscles?
Tendinous intersections
What is the function of tendinous intersections?
Improve mechanical efficiency
List the attachments of rectus abdominus
Xiphoid process and costal cartilages
Pubic bones and pubic symphysis
What is the rectus sheath?
Deep to superficial fascia, strong fibrous layer surrounding rectus abdominus muscles
What is the clinical relevance of the rectus sheath?
Combined aponeuroses of anterolateral abdominal wall muscles
What is the arcuate line?
Horizontal line that demarcates the lower limit of the posterior layer of the rectus sheath
When undertaking a suprapubic incision, both layers of rectus sheath will be present. True/ False?
False
Only anterior rectus sheath below the arcuate line
List the layers of the internal surface of the abdominal wall, up to the anterolateral abdominal wall muscles
Transversalis fascia
Extraperitoneal fat
Parietal peritoneum
List the spinal nerves that supply the abdominal wall from superior to inferior, and give their nerve roots
7th - 11th intercostal nerves
Subcostal (T12)
Iliohypogastric (L1)
Ilioinguinal (L1)
What do the intercostal nerves become when they leave the thorax and enter the abdomen?
Thoracoabdominal nerves
State the course of the nerves that supply the abdominal wall
Travel in plane between internal oblique and transverse abdominus
Describe the blood supply to the anterior abdominal wall
Internal thoracic artery –> Superior epigastric arteries
External iliac artery –> Inferior epigastric arteries
Describe the blood supply to the lateral abdominal wall
Posterior intercostal arteries –> Intercostal and subcostal arteries
The blood supply to the anterior abdominal wall passes posterior to what muscle?
Rectus abdominus
How does a surgeon minimise trauma to muscle fibres?
Incise in same direction as muscle fibre
During a LSCS incision, muscles are cut. True/ False?
False
Rectus muscles are seperated in lateral direction, moving them towards nerve supply
List the layers when opening, from superficial to deep, in a LSCS incision
Skin + fascia Anterior rectus sheath Rectus abdominus Transverse fascia + peritoneum Retract bladder Uterine wall Amniotic sac
List the layers to stitch closed, from deep to superficial, in a LSCS incision
Uterine wall with visceral peritoneum
Rectus sheath
Fascial layer if increased BMI
Skin
List the layers when opening, from superficial to deep, in a laparotomy
Skin + fascia
Linea alba
Peritoneum
List the layers to stitch closed, from from deep to superficial, in a laparotomy
Peritoneum + linea alba
Fascia if increased BMI
Skin
What is the clinical consequence of limited bleeding in a midline incision?
Poor healing
Increased risk of wound complications (dehiscence, incisional hernia)
List the possible sites for insertion of a laparoscopy port
Sub-umbilical (most common)
Lateral
Which vessels are at risk if a lateral port is used in laparoscopy? Why?
Inferior epigastric arteries
Emerge medial to deep inguinal ring
State the surface anatomy landmark used to identify the deep inguinal ring
Superior to the halfway point between ASIS and pubic tubercle
What is Hesselbach’s triangle?
Space bounded by the lateral border of the rectus abdominis medially, the inguinal ligament inferiorly, and the inferior epigastric vessels laterally.
How are the pelvic organs viewed in laparoscopy?
Position of uterus manipulated by grasping cervix with forceps
List the different types of hysterectomy procedures
Abdominal
Vaginal
Where is the incision made for an abdominal hysterectomy
Suprapubic or ‘bikini line’
Same as LSCS
Which vessels are at risk during hysterectomy? How can they be differentiated?
Ureter and uterine artery
Ureter passes inferior to artery, ‘water under bridge’
Ureter often vermiculates when touched
