1: Anatomy - Surgical incisions Flashcards
What
a) horizontal
b) vertical
incisions are most commonly carried out in obs & gynae?
a) Lower segment caesarean section
b) Laparotomy incision
At what level are Caesarean sections carried out?
2cm above pubic symphysis
measured as two finger breadths
On which line is a Caesarean incision made?
Suprapubic line
What are the three layers of abdominal fascia called?
Where are they found relative to the abdominal muscles?
Superficial - Camper’s fascia, Scarpa’s fascia; found superficial to external obliques
Deep - transversalis fascia; found deep to rectus abdominis and transversus abdominis
What are the four groups of abdominal wall muscles?
External obliques
Internal obliques
Rectus abdominis medially
Transversus abdominis laterally
What are the three layers of intercostal muscles?
External intercostals
Internal intercostals
Innermost intercostals
Which direction do the external oblique muscles run in?
Hands in pockets
Anterior direction
The external oblique muscles run in an (anterior / posterior) direction.
anterior direction
Which ribs do the external obliques attach to superiorly?
Ribs 5 - 11
Which structures do the external obliques attach to inferiorly?
Iliac crests
Pubic tubercle
Linea alba
What structure is a flattened aponeurosis found in the midline?
Linea alba
What structures are flattened aponeuroses found laterally?
Linea semilunaris
What is an aponeurosis?
Flattened tendon
The external obliques run in the same direction as which respiratory muscles?
External intercostals
Which direction do the internal obliques run in?
Posteriorly
i.e the opposite of external intercostals, remember hands in pockets
What fascia is found posteriorly?
Thoracolumbar fascia
Which abdominal muscles attach to the thoracolumbar fascia?
Internal obliques
Transversus abdominis
Which bony feature of the pelvis do all of the abdominal muscles attach to?
Iliac crest
Which flattened tendons make up the borders of rectus abdominis?
Linea alba in the midline
Linea semilunaris laterally
Tendinous intersections between the groups of muscles
What structures does the linea alba attach to superiorly and inferiorly?
Xiphoid process of the sternum superiorly
Pubic symphysis inferiorly
Which structure is made up of the combined aponeuroses of transversus abdominis, external oblique and internal oblique?
Rectus sheathe
Is rectus abdominis part of the rectus sheathe?
No
As in it doesn’t have an aponeurosis to contribute, it’s just surrounded by the rectus sheathe
Transversus abdominis is described as a corset muscle - why?
Keeps the abdominal organs contained within the abdominal cavity
Force of gravity pushes all these muscles downwards, creating a need for support
What is the advantage of tendinous intersections between the muscle groups of rectus abdominis?
Prevents bowstringing
If rectus abdominis was one long muscle it would contract in a weird way
What horizontal line marks a change in the structure of the rectus sheathe?
Arcurate line
Where exactly is the arcurate line?
Halfway between umbilicus and pubic crest
Describe the structure of the rectus sheathe above and below the arcurate line.
Above acurate line:
external oblique anterior to rectus, internal oblique split into two leaflets, one anterior and one posterior to rectus, transversalis fascia posterior to rectus
Below arcurate line:
everything is anterior to rectus apart from transversalis fascia
This gets asked about in exams
Which muscle is always superficial to rectus abdominis in the rectus sheathe?
External oblique
Which muscle splits into anterior and posterior leaflets in the rectus sheathe above the acurate line?
Internal oblique
Anterior leaflet is superficial to rectus, posterior leaflet is deep to rectus
Describe the structure of the rectus sheathe above the arcurate line.
External oblique superficial to rectus
Internal oblique split into two leaflet - anterior leaflet superficial to rectus, posterior leaflet deep
Transversalis fascia deep to rectus
Describe the structure of the rectus sheathe below the arcurate line.
External oblique superficial to rectus
Internal oblique superficial to rectus
Transversalis fascia deep to rectus
Name the layers of the abdominal wall from superficial to deep.
Skin
Subcutaneous fat
Superficial fascia - Camper’s and Scarpa’s fascia
External oblique
Internal oblique
Rectus / Transversus abdominis
Transversalis fascia
Parietal and visceral peritoneum
The layers of the spermatic cord from superficial to deep are
external spermatic fascia
cremasteric fascia
internal spermatic fascia
tunica vaginalis
which layers of the abdominal wall do these structures come from?
External spermatic fascia derived from external obliques
Cremasteric fascia derived from internal obliques
Internal spermatic fascia derived from transversalis fascia
Tunica vaginalis derived from parietal peritoneum
Which layers of the spermatic cord are given off by
a) parietal peritoneum
b) transversalis fascia
c) internal oblique
d) external oblique?
a) Tunica vaginalis
b) Internal spermatic fascia
c) Cremasteric fascia
d) External spermatic fascia
Which nerves supply the intercostal muscles?
What is their source?
Intercostal nerves
Anterior rami of thoracic spinal nerves (T7 - T11)
What is the blood supply of the
a) anterior
b) posterior
intercostal spaces?
a) Internal thoracic artery
b) Throracic aorta
What is the blood drainage of the
a) anterior
b) posterior
intercostal spaces?
a) Internal thoracic vein
b) Azygous vein
What are the internal thoracic arteries and veins also known as in women?
Internal mammary arteries and veins
Which nerves supply the abdominal muscles?
Thoracoabdominal nerves
Subcostal nerve
Iliohypogastric nerve
Ilioinguinal nerve
The intercostal nerves are derived from the anterior rami of which spinal nerves?
T7 - T11
The (ventral / dorsal) rami of spinal nerves provide motor fibres.
ventral rami
Which nerves are thoracoabdominal nerves a continuation of?
Intercostal nerves
Which spinal levels are the thoracoabdominal nerves derived from?
T7 - T11
same as intercostals (because they’re the same nerves)
What are the spinal levels of the
thoracoabdominal nerves
subcostal nerves
iliohypogastric nerves
ilioinguinal nerves?
Thoracoabdominal nerves - T7 - T11
Subcostal nerves - T12
Iliohypogastric nerves - L1
Ilioinguinal nerves - L1
Where in the rectus sheathe do the nerves of the abdominal wall travel?
Between internal oblique and transversus abdominis
i.e the anterior rectus sheathe, above AND below the arcurate line
Which arteries supply the anterior abdominal wall?
Superior epigastric artery
Inferior epigastric artery
although the inferior epigastric supplies the vast majority of the blood
Which anterior abdominal artery gives most of the blood supply?
Inferior epigastric artery
Where are the superior and inferior epigastric arteries found in relation to the rectus sheathe?
Deep to rectus abdominis
In which layer of the abdominal wall are the
a) thoracoabdominal nerves
b) superior and inferior epigastric artery
found?
a) Between internal oblique and transversus abdominis (anterior rectus sheathe)
b) Deep to rectus abdominis (posterior rectus sheathe)
Which major arteries are the
a) superior
b) inferior epigastric arteries a branch of?
a) Internal thoracic / mammary artery
b) External iliac artery
The superior epigastric artery is (anterior / posterior) to rectus abdominis.
The inferior epigastric artery is (anterior / posterior) to rectus abdominis.
They’re both posterior to rectus abdominis
Which type of incision can damage the thoracoabdominal, subcostal, iliohypogastric or ilioinguinal arteries?
Midline laparotomy incision
The superior epigastric arteries are a branch of?
Internal thoracic / mammary artery
The inferior epigastric arteries are a branch of?
External iliac artery
In a caesarean section, are the rectus abdominis muscles cut?
No
The linea alba is cut and they’re pushed laterally
Which organ needs to be pushed inferiorly in a Caesarean section?
Bladder
You do not want to cut this
What is the suprapubic line also known as?
Pfannenstiel / Kerr line
Where is the deep inguinal ring found?
Halfway between ASIS and pubic tubercle
What triangle is formed from the lateral border of rectus abdominis, the inguinal ligament inferiorly and the inferior epigastric artery medially?
Inguinal triangle
or Hesselbach’s triangle
What are the borders of the inguinal triangle?
Lateral border of rectus abdominis
Inferior epigastric artery superiorly
Inguinal ligament inferiorly
The deep inguinal ring is found halfway between the ASIS and the pubic tubercle.
Hernias MEDIAL to this must be ___.
direct
i.e popping through a muscular weakness, because the superficial inguinal ring is lateral to the deep one
The deep inguinal ring is halfway between the ASIS and the pubic tubercle.
Hernias LATERAL to this must be ___.
indirect
because the superficial ring, when indirect hernias pop out, is lateral to the deep inguinal ring
How do you tell the difference between a direct and indirect inguinal hernia on examination?
Reduce the hernia and then put pressure on the deep inguinal ring (halfway between ASIS and pubic tubercle), then ask the patient to cough
If it pops out, it’s direct (through rectus muscle)
If it doesn’t, it’s indirect (it passes through the deep inguinal ring, which you’re blocking)
Direct inguinal hernias occur (medial / lateral) to the inferior epigastric artery.
medial
because they herniate through the rectus, which is the medial border of the inguinal triangle
Indirect inguinal hernias occur (medial / lateral) to the inferior epigastric artery.
lateral
because they pop through the deep inguinal ring, which is lateral to the inguinal triangle
What is a hysterectomy?
Removal of the uterus
Which incision is used to carry out an abdominal hysterectomy?
Suprapubic / Pfannenstiel incision
same as for Caesarean section
Which phrase describes the relationship between the ureter and the uterine artery?
Water under the bridge
The ureter is always posterior to the uterine artery
What does the ureter do when you touch it?
Vermiculates
which means it wriggles like a worm - peristalsis
Which artery can be damaged by a lateral abdominal port procedure?
Inferior epigastric artery
Which structure passes posterior to the bladder in males?
Vas deferens
