Anatomy of Obs and Gynae Surgical Incisions

Question 1

List the two most common surgical incisions in O+G and their anatomical locations

Answer 1

Lower segment C-section (suprapubic, ‘bikini line’)

Laparoscopy (vertical midline incision)

Question 2

Which anatomical lines are used to determine location of incision and layers incised?

Answer 2

Langer’s lines

Question 3

List the layers of the anterolateral abdominal wall from superficial to deep

Answer 3

Skin
Superficial fascia
External oblique
Internal oblique
Transverse abdominus
Rectus sheath
Rectus abdominus

Question 4

What is the linea alba?

Answer 4

Midline blending of aponeuroses

Question 5

What is an aponeurosis?

Answer 5

Flat sheet or ribbon of tendon-like material that anchors a muscle or connects it with the part that the muscle moves

Question 6

List the attachments of external oblique

Answer 6

Lower ribs (5-11)
Iliac crest
Pubic tubercle
Linea alba

Question 7

Describe the orientation of fibres of external oblique

Answer 7

‘Hands in pockets’

Same direction as external intercostals - inferomedial

Question 8

List the attachments of internal oblique

Answer 8

Lower ribs (912)
Thoracolumbar fascia (posterior)
Iliac crest
Linea alba

Question 9

Describe the orientation of fibres of internal oblique

Answer 9

‘Hands in chest’

Same direction as internal intercostals - inferolateral

Question 10

List the attachments of transverse abdominus

Answer 10

Lower ribs
Thoracolumbar fascia
Iliac crest
Linea alba

Question 11

Describe the orientation of fibres of transverse abdominus

Answer 11

‘Corset muscle’

Transverse!

Question 12

What structures divide each rectus abdominus into 3 or 4 smaller muscles?

Answer 12

Tendinous intersections

Question 13

What is the function of tendinous intersections?

Answer 13

Improve mechanical efficiency

Question 14

List the attachments of rectus abdominus

Answer 14

Xiphoid process and costal cartilages

Pubic bones and pubic symphysis

Question 15

What is the rectus sheath?

Answer 15

Deep to superficial fascia, strong fibrous layer surrounding rectus abdominus muscles

Question 16

What is the clinical relevance of the rectus sheath?

Answer 16

Combined aponeuroses of anterolateral abdominal wall muscles

Question 17

What is the arcuate line?

Answer 17

Horizontal line that demarcates the lower limit of the posterior layer of the rectus sheath

Question 18

When undertaking a suprapubic incision, both layers of rectus sheath will be present. True/ False?

Answer 18

False

Only anterior rectus sheath below the arcuate line

Question 19

List the layers of the internal surface of the abdominal wall, up to the anterolateral abdominal wall muscles

Answer 19

Transversalis fascia
Extraperitoneal fat
Parietal peritoneum

Question 20

List the spinal nerves that supply the abdominal wall from superior to inferior, and give their nerve roots

Answer 20

7th - 11th intercostal nerves
Subcostal (T12)
Iliohypogastric (L1)
Ilioinguinal (L1)

Question 21

What do the intercostal nerves become when they leave the thorax and enter the abdomen?

Answer 21

Thoracoabdominal nerves

Question 22

State the course of the nerves that supply the abdominal wall

Answer 22

Travel in plane between internal oblique and transverse abdominus

Question 23

Describe the blood supply to the anterior abdominal wall

Answer 23

Internal thoracic artery –> Superior epigastric arteries

External iliac artery –> Inferior epigastric arteries

Question 24

Describe the blood supply to the lateral abdominal wall

Answer 24

Posterior intercostal arteries –> Intercostal and subcostal arteries

Question 25

The blood supply to the anterior abdominal wall passes posterior to what muscle?

Answer 25

Rectus abdominus

Question 26

How does a surgeon minimise trauma to muscle fibres?

Answer 26

Incise in same direction as muscle fibre

Question 27

During a LSCS incision, muscles are cut. True/ False?

Answer 27

False | Rectus muscles are seperated in lateral direction, moving them towards nerve supply

Question 28

List the layers when opening, from superficial to deep, in a LSCS incision

Answer 28

``` Skin + fascia Anterior rectus sheath Rectus abdominus Transverse fascia + peritoneum Retract bladder Uterine wall Amniotic sac ```

Question 29

List the layers to stitch closed, from deep to superficial, in a LSCS incision

Answer 29

Uterine wall with visceral peritoneum Rectus sheath Fascial layer if increased BMI Skin

Question 30

List the layers when opening, from superficial to deep, in a laparotomy

Answer 30

Skin + fascia Linea alba Peritoneum

Question 31

List the layers to stitch closed, from from deep to superficial, in a laparotomy

Answer 31

Peritoneum + linea alba Fascia if increased BMI Skin

Question 32

What is the clinical consequence of limited bleeding in a midline incision?

Answer 32

Poor healing | Increased risk of wound complications (dehiscence, incisional hernia)

Question 33

List the possible sites for insertion of a laparoscopy port

Answer 33

Sub-umbilical (most common) | Lateral

Question 34

Which vessels are at risk if a lateral port is used in laparoscopy? Why?

Answer 34

Inferior epigastric arteries | Emerge medial to deep inguinal ring

Question 35

State the surface anatomy landmark used to identify the deep inguinal ring

Answer 35

Superior to the halfway point between ASIS and pubic tubercle

Question 36

What is Hesselbach's triangle?

Answer 36

Space bounded by the lateral border of the rectus abdominis medially, the inguinal ligament inferiorly, and the inferior epigastric vessels laterally.

Question 37

How are the pelvic organs viewed in laparoscopy?

Answer 37

Position of uterus manipulated by grasping cervix with forceps

Question 38

List the different types of hysterectomy procedures

Answer 38

Abdominal | Vaginal

Question 39

Where is the incision made for an abdominal hysterectomy

Answer 39

Suprapubic or 'bikini line' | Same as LSCS

Question 40

Which vessels are at risk during hysterectomy? How can they be differentiated?

Answer 40

Ureter and uterine artery Ureter passes inferior to artery, 'water under bridge' Ureter often vermiculates when touched