Abdominal Wall Anatomy Flashcards
Name the 12 layers of the abdominal wall.
- Skin
- Camper Fascia
- Scarpa & Colle Fascia
- Superficial Investing Fascia
- External Oblique Muscle
- Intermediate Investing Fascia
- Internal Oblique Muscle
- Deep Investing Fascia
- Transversus Abdominus Muscle
- Transversalis Fascia
- Extraperitoneal Fat
- Parietal Peritoneum
Which 3 muscles compose the “flat muscles” of the abdominal wall?
- External Oblique
- Internal Oblique
- Transversus Abdominus
Fiber orientation of External Oblique
inferomedial (hands in pockets)
2 tissue types of external oblique muscle and border where tissue type changes
Muscular and aponeurotic
changes at MCL
Anterior Origin of External Oblique
Ribs 5-12
Insertion of External Oblique
Linea Alba, Pubic Tubercle, Anterior Iiac Crest
Innervation of External Oblique Muscle
Thoracoabdominal Nerve
The thoracoabdominal nerve originates from which roots?
T7-T11 and the subcostal nerve (T12)
Action of external oblique muscle.
flex and twist the trunk
compress/support viscera
The inferior margin of this muscle forms the inguinal ligament.
external oblique
The inguinal ligament runs from _____ to _____
ASIS to Pubic Tubercle
Fiber orientation of Internal Oblique
inferolateral (perpendicular to external oblique)
Origin of Internal Oblique
Thoracolumbar fascia (posterior)
Anterior 2/3 of iliac crest (lateral)
Tissue deep to lateral 1/3 of inguinal ligament
Insertion of internal oblique
inferior border of ribs 10-12 (posterior)
Linea Alba (anterior)
Innervation of internal oblique muscle
thoracoabdominal nerves (T7-T11)
Subcostal nerve (T12)
L1 anterior Ramus
Actions of internal oblique
flex/rotate trunk
compress/support viscera
fiber orientation of transversus abdominus
transverse
origin of transversus abdominus
Costal Cartilage 7-12
thoracolumbar fascia
iliac crest
connective tissue deep to lateral 1/3 of inguinal ligament
insertion of transverse abdominus
linea alba
pubic crest
innervation of transversus abdominus
thoracoabdominal nerves (T7-T11)
Subcostal nerve (T12)
L1 anterior ramus
Action of transversus abdominus
compress abdominal contents
no trunk movement
What are the 2 vertical abdominal muscles?
Rectus Abdominus
Pyramidalis muscle
Origin and insertion of rectus abdominus
O: pubic symphysis and crests
I: xiphoid process, 5-7 costal cartilage.
Innvervation of rectus abdominus
thoracoabdominal nerve (T7-T11)
Subcostal nerve (T12)
Action of rectus abdominus
flexion of trunk
stabilize tilt of pelvis
compress viscera
What tissue covers the rectus abdominus?
Rectus sheath
Origin and insertion of pyramidalis muscle
O: anterior surface of pubis
I: linea alba
Does pyramidalis sit deep or superficial to rectus abdominus?
superficial
What percentage of people do not have a pyramidalis muscle?
20%
Action of pyramidalis
tense linea alba
Which two important arteries lie within the rectus sheath deep to rectus abdominus?
Superior Epigastric Artery
Inferior Epigastric Artery
This line resides about one third of the distance between the umbillicus and the pubis
Arcuate line
Above this point, the rectus sheath does not have a posterior layer.
Therefore, the rectus abdominus rests directly on thoracic wall
Above costal margin
The anterior layer of the rectus sheath beneath the costal margin is composed of these two aponeurosis…
external oblique aponeurosis and anterior lamina of internal oblique aponeurosis
The posterior layer of the rectus sheath beneath the costal margin is composed of these two aponeurosis…
posterior lamina of interior oblique aponeurosis
aponeurosis of transversus abdominus
Below the arcuate line, the anterior rectus sheath is composed of which layers?
aponeurosis of external oblique, internal oblique and transversus abdominus
Below the arcuate line, the posterior rectus sheath is composed of which layers?
None… only transversalis fascia
Why do hernias tend to occur below the arcuate line?
no posterior rectus sheath
4 major nerve groups which provide sensory innervation to anterolateral abdominal wall…
Thoracoabdominal nn. (T7-T11)
Subcostal n. (T12)
Iliohypogastric n. (L1)
Ilioinguinal n. (L1)
thoracoabdominal nerves are continuation of intercostal nerves which run between which muscle layers?
Internal oblique and Transversus abdominus
The anterior cutaneous branches of thoracoabdominal nerves from T7-T9 innervate the skin where?
above the umbilicus
The anterior cutaneous branch of thoracoabdominal nerve from T10 innervates the skin where?
at the umbilicus
The anterior cutaneous branch of thoracoabdominal nerve from T11 innervates the skin where?
just below umbilicus
The subcostal nerve’s anterior and lateral cutaneous branches provide sensory innervation of what region?
below umbilicus to iliac crest
The anterior ramus of L1 splits into which two nerves?
iliohypogastric n.
ilioinguinal n.
which branch of L1 lies superior, iliohypogastric or ilioinguinal?
iliohypogastric
The iliohypogastric nerve provides motor innervation to which muscles?
internal oblique and transverse abdominus
the iliohypogastric nerve provides sensory innervation where?
over iliac crest, upper iliac and hypogastric regions
the ilioinguinal nerve provides motor innervation to which muscles?
inferior portion of internal oblique and transverse abdominus
The ilioinguinal nerve provides sensory innervation to…
skin overlying low inguinal region, mons pubis, anterior scrotum/labia majora and medial thigh.
In general, the neurovascular components of abdominal wall rest between these two muscles…
internal oblique and transverse abdominus
The superior epigastric artery is a continuation of the _______ artery, a branch directly off of the subclavian artery
internal thoracic artery (internal mammary artery)
Where is the anastomosis between superior and inferior epigastric arteries?
level of umbilicus
The inferior epigastric artery is a branch of the ______ artery…
external iliac artery
The inferior epigastric artery branches from the external iliac artery where?
superior to inguinal ligament
The inferior epigastric artery travels superiorly in the ________ fascia, entering the rectus sheeth where?
transversalis fascia
below arcuate line
This artery is a branch of the internal thoracic artery which supplies the anterolateral parts of the diaphragm and hypochondriac area…
musculophrenic a.
This artery is a branch of the external iliac artery which supplies the deep abdominal wall in the inguinal region
deep circumflex iliac artery
This artery is a branch of the femoral artery and supplies the superficial inguinal region
superficial circumflex inguinal artery
This artery is a branch of the femoral artery which supplies the superficial abdominal wall of the pubic and inferior umbilical regions of the abdomen
superficial epigastric artery
These three arteries are direct branches of the aorta, and provide blood to the anterolateral abdominal wall
10th and 11th posterior intercostal arteries
subcostal artery
Venous drainage of the skin overlying the abdominal wall is provided by a plexus of veins which drain into which 4 veins?
- internal thoracic (superomedial)
- Lateral Thoracic Vein (superolateral)
- /4. Superficial and inferior epigastric veins (inferior)
The superficial and inferior epigastric veins drain to the ______ vein which drain into the _______ vein
external iliac v.
femoral v.
Cutaneous veins around the umbilicus anastomose with the _______ veins, which are tributaries to the _______
paraumbilical veins
hepatic portal vein
Caput medusa occurs when the portal vein refluxes to ______
paraumbilical/cutaneous venous anastomoses
T or F:
The deep veins of the abdominal wall contain the same names as the arterial supply…
True
superficial lymphatic drainage above the umbilicus drain to which 2 major groups of lymph nodes…
axillary and parasternal nodes
superficial lymphatic drainage inferior to the umbilicus drain to which group of lymph nodes?
superficial inguinal lymph nodes
The deep lymphatic drainage accompany the deep veins of the abdominal wall, and drain to which 2 groups of lymph nodes?
external and common iliac nodes
r/l lumbar nodes
5 umbilical folds on the internal surface of the anterolateral abdominal wall…
Medial umbilical fold
R/L medial umbilical fold
R/L lateral umbilical fold