anterior and posterior abdominal wall and diaphragm Flashcards
what are the components of the abdominal wall?
musculoaponeurotic walls anterolaterally
diaphragm superiorly
pelvic floor muscles inferiorly
lumbar section of vertebral column posteriorly
what does the diaphragm cover?
the anatomical thoracic outlet serving as a partition to separate the abdominal and thoracic cavities
what do the pelvic floor muscles attach to?
the bony ring of the pelvic girdle- important because shows abdomen and pelvis are continuous cavities
what is internal pressure (intra-abdominal pressure) controlled by?
either voluntarily or reflexively by the contraction/relaxation of the diaphragm and anterolateral muscular walls
for generalized localization how many quadrants are there and what divides them?
4 divided by the median plane and the transumbilical plane
for specific localization how many regions are there and what divides them?
9 regions by the 2 vertical midclavicular lines and the 2 horizontal lines (subcostal plane and transtubercular plane)
where does the subcostal plane run?
touching the inferior border of the 10th costal cartilage on both sides
where does the transtubercular plane run?
the tubercle of the ilium on the iliac crest going through the body of the 5th lumbar vertebrae
what are the functions of the anterolateral abdominal wall?
(1) form a strong expandable support for the abdominal wall
(2) protect the abdominal viscera from injury
(3) oppose the diaphragm in respiration
(4) move the trunk/maintain posture
what is the anterolateral abdominal wall bounded superiorly by?
the cartilages of the 7th-10th ribs and the xiphoid process
what is the anterolateral abdominal wall bounded inferiorly by?
the inguinal ligament and superior margins of the anterolateral aspects of the pelvic girdle
what does the anterolateral abdominal wall consist of?
skin and subcutaneous tissue (which contains fat, muscles and their aponeuroses and deep fascia), extraperitoneal fat and parietal peritoneum
what are the four major pairs of muscles that compose the anterolateral abdominal wall?
external abdominal oblique
internal abdominal oblique
transverse abdominal
rectus abdominis
which muscle is the principle vertical muscle of the anterior abdominal wall and is much wider superiorly tapering inferiorly?
rectus abdominis
which muscle is often absent but it very small paired muscle most anteriorly and inferiorly that draws the linea alba downward towards the pelvis?
pyramidalis
what does the linea semilunaris represent?
the lateral limit of the rectus sheath
what is the inguinal ligament?
a retinacular structure – it holds down the structures passing between the pelvis and the thigh. It represents a thickening of external oblique aponeurosis running from the ASIS to the pubic tubercle. The deeper two flat muscles attach to it laterally
what is the rectus sheath?
a strong, incomplete fibrous compartment of the rectus abdominis and pyramidalis muscles. It contains some nerves and vessels too, most notably the inferior (and superior) epigastric arteries and veins. It is formed by the crossing and splitting of the aponeuroses of the more transverse muscle layers
which aponeurosis splits superiorly and surrounds the rectus muscle?
the internal oblique aponeurosis
what covers the posterior part of the rectus muscle?
the transverslais fascia
what is the arcuate line?
the line of demarcation represents the inferior limit of the posterior layer of the rectus sheath.
the internal thoracic artery splits into what two arteries?
musculophrenic and superior epigastric a
the abdominal aorta gives off which branch that travels with anterior rami of lower thoracic spinal nerves along inferior edges of ribs?
posterior intercostal a
the external iliac/femoral artery give off what 3 branches?
superficial epigastric, cicrumflex iliac, and inferior epigastric a
what do the anterior rami of spinal nerves T7-T12 travel within?
the posterior thoracic wall
what do the lower intercostal nerves continue as when then reach the costal margin and continue traveling anteromedially?
thoracoabdominal nerves
do the thoracoabdominal nerves participate in the plexus formation?
NO
where do the intercostal nerves travel between?
the innermost and internal intercostal muscles and continue between the internal oblique and transverse abdominal muscles
what structure does the anterior cutaneous branches pierce?
the rectus sheath
what is the inguinal canal?
formed to permit the descent of the testes during fetal life. In adults, both male and female, the canal is an oblique passage about 4cm long directed inferomedially through the inferior part of the anterior abdominal wall. It is parallel and superior to the medial half of the inguinal ligament – the thickened, inferior edge of the external oblique aponeurosis. It represents successive deficiencies in the three muscular layers of the wall, staggered medial to lateral
what are the openings to the inguinal canal?
deep inguinal ring and superficial inguinal ring
what is the lacunar ligament?
deep fibers of inguinal ligament attaching to superior pubic ramus that forms the medial border of subinguinal space
what are the lateral and medial crura; intracrural fibers?
parts of the external oblique aponeurosis which surround the superficial inguinal ring
what is the inguinal falx (conjoint tendon)?
medial reinforcement of the posterior wall of the inguinal canal formed by the fused aponeuroses of internal oblique and transversus abdominis
which type of hernia is more common?
indirect inguinal hernia. it enters deep inguinal ring lateral to inferior epigastric v
list the umbilical folds
lateral umbilical folds (paired)= inferior epigastric a and v
medial umbilical folds (paired)= obliterated umbilical arteries
median umbilical fold (single)= obliterated urachus
where is the supravesical fossae?
between medial/medial folds
where is the medial inguinal fossae?
aka “hasselbach triangle” between medial/lateral folds
where is the lateral inguinal fossae?
lateral to lateral fold (most common area for inguinal hernia)
what are the boundaries of the inguinal (Hasselbach) triangle?
rectus abdominis muscle (medially)
inguinal ligament (inferiorly)
inferior epigastric artery and vein (laterally)
what is the deficit in the transverse abdominal muscle lateral to the vessels?
the deep inguinal ring
what is the spermatic cord?
contains structures running to and from the testis, and it suspends the testis in the scrotum
where does the spermatic cord run?
It begins at the deep inguinal ring andends on the posterior aspect of the testis
what are the fascial coverings of the spermatic cord derived from?
the layers of the anterolateral abdominal wall
what are the contents of the spermatic cord?
ductus deferens, testicular artery, pampiniform venous plexus, autonomic nerves, genital branch of the genitofemoral nerve, lymphatic vessels
what is the ductus deferens?
a muscular tube which conveys sperm from the epididymis to the ejaculatory duct (within the prostate)
what doe the testicular artery supply?
blood supply to the testis and epididymis, off the aorta
where does the pampiniform venous plexus empty?
into the right and left testicular veins
list the coverings of the spermatic cord deep to superficial and what they are derived from the abdominal wall
peritoneum- correlates to tunica vaginalis
internal spermatic fascia- from transversalis fascia
cremasteric fascia- from internal oblique muscle and aponeurosis
external spermatic fascia- external oblique aponeurosis
subcutaneous fascia
skin
which muscle of the abdomen doesn’t contribute to the coverings of the testis/spermatic cord
transverse abdominal m
what is hip-hiking from?
an abnormality in gait characterized by loss of abducting power by the gluteus medius m. As a result, the quadratus lumborum lifts the ipsilateral hemipelvis to initiate abduction
describe the diaphragm
the musculoaponeurotic partition separating the thoracic and abdominopelvic cavities. Its primary role is in inspiration. Three muscular parts(attaching to structures forming the inferior thoracic aperture) all attach to central tendon.
which crura crosses midline and forms the esophogeal hiatus?
right
what provides blood supply to the diaphragm?
pericardiacophrenic a, the superior and inferiorphrenic a
what provides innervation to the diaphragm?
phrenic n. (motor and central somatosensation), thoracicanterior rami (somatosensation only, to peripheral parts)
what do the subcostal nerves supply?
oblique muscles and skin of the anterolateral abdominal wall superior to iliac crest and inferior to umbilicus
what are the major divisions of L1?
iliohypogastric and ilioinguinal nerves
where do the iliohypogastric and ilioinguinal nerves run?
they pass deep to the medial arcuate ligament and over the quadratus lumborum muscle. They pierce the transverse abdominal muscle near the ASIS and pass inferomedially to their targets
what are the targets of the iliohypogastric nerve?
skin over iliac crest, upper inguinal and hypogastricregions and superolateral quadrant of buttock and internal oblique and transverse abdominal muscles
what are the targets of the ilioinguinal nerve?
skin of lower inguinal region, mons pubis/labia majora and anterior scrotum, and adjacent medial thigh and the inferior most internal oblique and transverse abdominal muscles
what muscle does the genitofemoral nerve pierce?
psoas major
what are the branches of the genitofemoral nerve?
the genital branch travels in the spermatic cord to supply cremaster muscle and the femoral branch supplies cutaneous innervation to skin overlying the femoral triangle. In female, anterior labia majora skin is innervated; in males, anterior scrotum and proximal medial thigh.
where does the lateral cutaneous nerve of the thigh run?
emerges from posterior to the psoas and runs on the iliacus toward the lateral part of the inguinal ligament. It courses deep to it, just medial to the ASIS and into the proximal thigh
where does the femoral nerve run and supply?
emerges near the lateral border of the psoas, innervates the iliacus and continues on deep to the inguinal ligament to supply the flexors of the hip and extensors of the knee. Also, the majority of skin on the anterior thigh
where does the obturator nerve run?
emerges from the medial border of the psoas. It travels inferiorly, and through the obturator foramen to supply the adductors of the thigh and skin on medial thigh
what does the. lumbosacral trunk pass over in order to participate in the sacral plexus?
the ala of the sacrum
what are the thoracic splanchnics?
the main source of presynaptic sympathetic fibers to the abdominal viscera
the postsynaptic sympathetic neurons destined for distribution to the abdominal wall and lower limbs emerge as?
gray rami from the ganglia near lower intercostal nerves and lumbar plexus nerves
The great, lesser and least splanchinic nerves pierce the crura of the diaphragm and are destined for
the celiac, superior mesenteric and aorticorenal ganglia.
what is the name of the nerves that synapse on prevertebral ganglia an descend in the hypogastric plexus/hypogastric n?
lumbar splanchnic nerves
where does the vagus nerve run?
participate in the esophageal plexus and emerge as anterior and posteriorvagal trunks which pass through the esophageal hiatus on the anterior and posterior surfaces(respectively) of the esophagus and stomach
are all the parasympathetic fibers destined for the gut presynaptic, postsynaptic, or neither?
presynaptic
branches emerge from the aorta in how many planes?
3 vascular planes
where does the abdominal aorta run?
at the aortic hiatus (around the level of T12 vertebra) and ends at the level of L4
what does the abdominal aorta divide into?
left and right common iliac arteries (at about the level of the iliac crests)
what are the unpair branches of the abdominal aorta?
to foregut- celiac trunk
to midgut- superior mesenteric a
to hindgut- inferior mesenteric a
what are the paired branches of the abdominal aorta?
the lateral visceral branches- renals and suprarenals and gonadals and posterolateral parietal branches- inferior phrenics, lumbars
what does the common iliac arteries divide into?
internal iliac- to the pelvis
external iliac- to the lower extremities
what is the name of the artery that might be thought of as a very small “continuation” of the abdominal aorta?
median sacral artery
