Abdomen- abdominal wall Flashcards
Branches of coeliac artery
Left gastric
Splenic
Common hepatic
Branches of common hepatic artery
Proper hepatic artery
Gastroduodenal artery
Right Gastric artery
Branches of gastroduodenal artery
Right gastroepiploic artery
Supraduodenal artery
Superior anterior pancreaticoduodenal artery
Branches of proper hepatic artery
Left proper hepatic artery
Right proper hepatic artery -> cystic artery
Lesser sac vs greater sac of abdomen
Space created by lesser and greater omentum
Diaphragm insertions
Median arcuate ligament over aorta
Right Crus - L3
Left Crus - L2
Medial arcuate ligament - Psoas major
Lateral arcuate ligament - Quadratus Lumborum
Superficial abdominal fascia layers
Camper’s fascia
Scarpa’s fascia
Camper’s fascia features
Contains large amounts of fat
Continuous over inguinal ligament and perineum
Scarpa’s fascia features
Mainly fibrous tissue (little fat)
Called fascia lata when enters lower limb
Continuous with superficial perineal fascia (Colle’s fascia)
Forms darto’s fascia
The dartos fascia is a thin layer of tissue in the scrotum that’s made of smooth muscle. It’s also known as the dartos muscle. The dartos fascia helps regulate the temperature of the testes and controls the appearance of the scrotum.
Transversalis fascia
deep fascia layer below transversus abdominus
External oblique muscle aponeurosis cover
Most superficial
Ends at inguinal ligament
Ligaments associated with inguinal ligament
Lacunar: inguinal ligament to pecten pubis
Pectineal (cooper’s) ligament
Innervation of flat muscles of anterior abdo wall (eg external/internal oblique/transversus)
T7-T12
Iliohypogastric (EO/IO/TA)
Ilioinguinal (IO/TA)
Flat muscles of abdo wall
External oblique
Internal oblique
Transversus abdominus
The muscles of the anterolateral abdominal wall can be divided into two main groups:
Flat muscles – three flat muscles, situated laterally on either side of the abdomen.
Vertical muscles – two vertical muscles, situated near the mid-line of the body (rectus and pyramidalis)
Midline muscles of anterior abdo wall
Rectus abdominis
Pyramidalis
Upper and lower quarters of rectus sheath
Anatomical relevance of Arcuate line (of Douglas)
The border between upper 3/4 and lower 1/4 of rectus abdominis / half way between the umbilicus and pubic symphysis
In order to perform a horizontal incision, first you need to locate the arcuate line, which lies below the umbilicus posterior to the rectus abdominus and **marks the inferior limit of the posterior rectus sheath. **
This is done in order to identify the inferior epigastric arteries (originating from the external iliac artery) - which supply the inferior portion of the rectus abdominis as they ascend on its posterior surface to enter the sheath at the arcuate line. Here they anastamose with the vessels of the superior epigastric vessels (originating from the internal thoracic artery)
Since there’s no supporting posterior rectus sheath below the arcuate line, this is where the inferior epigastric arteries are most susceptible to injury, so they need to be located and ligated when performing a horizontal incision in order to prevent significant hemorrhage (for example pfannenstiel incision)
https://www.osmosis.org/learn/Anatomy_clinical_correlates:_Anterior_and_posterior_abdominal_wall
All the layers of abdominal wall
Note the extra-peritoneal fascia
Innervation of anterior abdominal wall
Lateral and anterior cutaneous branches of T7 to T12 (
Ilio-hypogastric nerve (L1)
Ilio-inguinal nerve (L1)
Clinical: These are the nerves that can be damaged during incision for abdo surgery.
For example Kocher Incision can lead to nerve damage to the T7 and T8 thoracic spinal nerves - leading to loss of sensation, power and pain.
Kocher (aka as subcostal incision) can also give access to the spleen if the incision is extended.
Clinical correlates of anterior wall - https://www.osmosis.org/learn/Anatomy_clinical_correlates:_Anterior_and_posterior_abdominal_wall
Blood supply of upper anterior abdominal wall
Internal thoracic artery gives rise to:
- Musculophrenic artery
- Superior epigastric artery
- Intercostal arteries
Arterial supply of inferior abdo wall
Femoral artery: 2X superficial arteries
- Superficial epigastric artery
- Superficial circumflex artery
External iliac artery:
- Inferior epigastric
- Deep circumflex artery
Superficial lymph drainage of abdo wall
Above umbilicus: axillary nodes
Below umbilicus: superficial inguinal nodes
Deep lymph drainage of anterior abdo wall
parasternal
lumbar
external iliac
Linea semiluranis
Border of rectus abdominis
Inferior epigastric artery crosses it
Transpyloric plane (L1) landmark for which structures
Pylorous stomach
Left kidney
Fundus of gallbladder
Neck of pancreas
Duodenojejunal flexure
SMA
Portal vein
L + R colic flexures
Root of transverse mesocolon
2nd part of duodenum
spleen
Which part of diaphragm does oesophagus pierce to enter abdomen
Oesophageal hiatus - Muscular sling formed by right crus of diaphragm at **T10 **
T8 - Vena Cava
T10- Oesophagus
T12 - Aorta
T8: The caval hiatus, which allows the inferior vena cava to pass through
T10: The esophageal hiatus, which allows the esophagus, vagus nerves, and other structures to pass through
T12: The aortic hiatus, which allows the aorta, thoracic duct, and azygos vein to pass through
Blood supply of lesser omentum
Right/left gastric arteries
The lesser omentum transports the arteries for the lesser curvature of the stomach; the right and left gastric arteries
The xiphoid lies at which vertebral level?
T9
The transpyloric plane (of addison) lies at which vertebral level and passes through which structures?
L1 - can be approximated by using a hands breath below the xiphoid.
Pylorus
Pancreatic Neck
The duodenojejunal flexure
Fundus of the gall bladder
The tip of the 9th costal cartilage
The hila of BOTH kidneys
It also corresponds to the level of termination of the spinal cord
The subcostal plane corresponds to which level of the spinal cord?
L3 - Lowest level of the costal margin (inferior to the margin of the 10th rib) - it passes through the origin of the inferior mesenteric artery
The supracristal plane can be found at which vertebral level?
L4 - the summits of the iliac crests and bifurcation of the aorta. (also useful for lumbar puncture as well below end of spinal cord L1)
Scarpas (fibrous fascia) extends continuosly to become which structures?
Blends with the deep fascia of the thigh, extends into the penis and scrotum (labia majora in women) and into the perineum as colles fascia.
The segmental nerve supply of the abdominal muscles and overlying skin is derived from levels ____.
This can roughly be remembered as the umbilicus is supplied by _____ and the groin (ilioinguinal) and scrotum (iliohypogastric) supplied by _____
Any abdominal incision can damage these nerves leading to muscle wall weakness and hernias,
T7-T12/L1
T10
L1
T12 is also known as the subcostal nerve
Both iliohypogastric and ilioinguinal nerves have only sensory function. The iliohypogastric nerve provides sensation to the skin of the gluteal and hypogastric regions; the ilioinguinal nerve provides sensory innervation to the skin that overlies the groin, inner thigh, and labia majus.
The rectus abdominis arises on a 7.5 cm horizontal line from the ___, ___, ___ costal cartilages and inserts at a length of 2.5 cm at the _____.
Arises from the 5th 6th and 7th costal cartilages
and
Inserts at the pubic crest
At the tip of the xiphoid, the umblicus and halfway inbetween there lies 3 transverse tendinous intersections (sometimes a fourth below the umbilicus) . These tendinous intersections exist only on the anterior surface and here they adhere to the rectus sheath!
At each intersection vessels from the superior epigastirc artery and vein pierce the rectus.
The sheath (rectus) in which the rectus abdominis is formed to a large extent by the aponeuroses of the lateral abdominal muscles. (i.e external and internal oblique and the transversus muscle)
https://www.osmosis.org/answers/arcuate-line
Why is the midline incision preferred to the paramedian incision?
Midline incision cuts through any part of the linea alba (from the xiphoid process to the pubic symphisis) - this incision is preferred as the linea alba contains smaller blood vessels and nerves - Lower risk of haemorrhage and nerve
Paramedian Incision - costal margin to the pubic hairline
The _____ incision (aka known as ___) can be used for appendicectomies and in inferomedial incision in oblique orientation to follow the mucle fibres of the ______
Mcburney (aka gridiron)
External Oblique
Mcburneys point is **1/3 the way from the ASIS to the umbilicus **
Which incision is used for a left and right colonic resection?
Rutherford Morrison Incision
Similar to the mcburney incision but on the other side - an oblique incision that runs infero-medially along the fibers of the external oblique
_____ incisions (and lesser so ___) through the lateral abdominal wall do not damage their richly anastomosing nerve supply and heal without weakness.
Transverse incisions are useful for ___ or ___ cases
Transverse and oblique incisions through the lateral abdominal wall
Paediatric or vascular cases
The McBurney incision is usually preferred to the ____ incision for appendicectomies because ___
Lanz (transverse) Incision
Due to risk of damage to the anterior branch of the Iliohypogastric nerve which can leave reduced sensation over the suprapubic region
The suprapubic or _____ incisions, also called bikini incisions. These are made at the pubic hairline or ____. These types of incisions are horizontal with a slight convexity and are used for most gynecological and obstetrical operations, like a cesarean section. Once this incision is made, the _____ is resected, and the _____ muscles are retracted laterally.
Care must be taken to not damage the _____ nerves, as damage to these could result in sensory deficits of the suprapubic and genital region.
In order to perform a horizontal incision, first you need to locate the arcuate line, which ______ . This is done in order to identify the inferior epigastric arteries, which supply the inferior portion of the rectus abdominis as they ascend on its posterior surface to enter the lateral aspect of the muscle at the arcuate line.
Since there’s no supporting posterior rectus sheath below the arcuate line, this is where the inferior epigastric arteries are most susceptible to injury, so they need to be located and ligated when performing a horizontal incision in order to prevent significant hemorrhage.
Pfannenstiel
5cm above the pubic symphysis.
linea alba and anterior rectus sheath
rectus and pyramidalis
iliohypogastric or ilioinguinal
Arcuate line : lies below the umbilicus posterior to the rectus abdominus and marks the inferior limit of the posterior rectus sheath
The origin and insertions of the rectus abdominis muscle
Origin: Pubic Crest
Insertion:
- Xiphoid process of the sternum
- Costal cartilages of ribs 5-7.
Actions: As well as assisting the flat muscles in compressing the abdominal viscera, the rectus abdominis also stabilises the pelvis during walking, and depresses the ribs.
Innervation: Thoracoabdominal nerves (T7-T11).
Abdominis rectus 57
The origin and insertion(s) of the external oblique
The external oblique is the largest and most superficial flat muscle in the abdominal wall. Its fibres run inferomedially.
Origin: outer surface of **lower 8 ribs (ribs 5-12) **
Insertion:
(1) Pubic tubercle
(2) Iliac Crest
(3) Xiphoid
(4) Linea alba
Actions: Contralateral rotation of the torso.
Innervation: Thoracoabdominal nerves (T7-T11) and subcostal nerve (T12).
https://www.kenhub.com/en/library/anatomy/external-abdominal-oblique-muscle
The inguinal ligament aka as _____ is formed by the thickened, reinforced free inferior edge of the aponeurosis of the external oblique muscle as this attaches to the bones of the pelvis. The superior attachment of the inguinal ligament is on the anterior superior iliac spine of the ilium.
Pouparts Ligament
Internal oblique origin and insertions
The internal oblique lies deep to the external oblique. It is smaller and thinner in structure, with its fibres running superomedially (perpendicular to the fibres of the external oblique).
Originates from the:
**1. Inguinal ligament
2. Iliac crest
3. Lumbodorsal fascia. **
It inserts onto ribs 10-12.
Actions: Bilateral contraction compresses the abdomen, while unilateral contraction ipsilaterally rotates the torso.
Innervation: Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus.
Transversus abdominis origins and insertions
Origin:
1. Lower 6 costal cartilages
2. lumbar fascia
3. Iliac crest (anterior 2/3)
4. Inguinal ligament (lateral 1/3)
Insertion:
- Linea alba
- Pubic crest (via the conjoint tendon - also internal oblique)
- Xiphoid process
Actions: Compression of abdominal contents.
Innervation: Thoracoabdominal nerves (T7-T11), subcostal nerve (T12) and branches of the lumbar plexus.
Nerve supply of abdominal muscles
Rectus abdominis and external oblique:
Internal oblique and transversus abdominis:
T7 - T12 only
T7-T12 AND Iliohypogastric and ilioinguinal nerves
A ____ hernia emerges at the lateral aspect of the ___ at the level of the arcuate line of douglas
Spigelian
rectus sheath
Rupture of the rectus muscle can lead to a rectus sheath haematoma due to ___
The superior and inferior epigastric vessels being applied closely to the posterior rectus abdominus muscle.
Above the costal margin the rectus sheath is formed by ____
The external oblique only
Above the arcuate line the rectus sheath is formed by ____
Anteriorly: The external and internal oblique
Posteriorly : The internal oblique and traversus abdominis
(the internal oblique splits its aponeuroses in two - anteriorly and posteriorly to the rectus abdominis and then fuses to form the linea alba which runs from the xiphisternum to the pubic symphysis)
Below the arcuate line the sheath is comprised of the 3 aponeuroses of the 3 lateral abdo wall muscles blended together.
Posteriorly, at this level, lies the only remaining structures ____
The Transversalis fascia (the thickened extraperitoneal fascia of the lower abdominal wall) and the peritoneum (parietal).
Origin of the inferior epigastric artery and vein?
External iliac artery artery and vein
Origin of the superior epigastric artery and vein?
Internal thoracic artery and vein
Superior and inferior epigastric veins anastamose along the posterior surface of the rectus abdominis muscle at the level of the arcuate line (the end of the posterior rectus sheath)
The Inferior epigastric arteries are free below this level and not protected by aponeuroses and so are more susceptible to injury and haemorrhage
Pyramidalis muscle attachments, function and innervation
This is a small triangular muscle, found superficially to the rectus abdominis. It is located inferiorly, with its base on the pubis bone, and the apex of the triangle attached to the linea alba.
Attachments: Originates from the pubic crest and pubic symphysis before inserting into the linea alba.
Actions: Tenses the linea alba.
Innervation: Subcostal nerve (T12).
