Anatomy Flashcards
What is in the superior border (roof) of the abdominopelvic cavity?
diaphram, ribcage (attaches at ribs 7-10 & xyphoid)
What is in the inferior border (floor) of the abdominopelvic cavity?
pelvic bones (ileum, ischium, & pubis [pairs] & pelvic diaphragm
What is included in the posterior wall of the abdominopelvic cavity?
lumbar spine, quadratus lumborum, & spinal muscles
What is included in the anterolateral walls of the abdominopelvic cavity?
musculoponeurotic layers (multiple)
What are the boundaries of the anterolateral abdominal wall?
- Superiorly- 7th-10th ribs & xyphoid
- Inferiorly- inguinal ligament & rim of pelvis (ilac crest, pubic crest, & pubic symphysis)
What does the anterolateral wall consist of?
skin, subq, muscles (& their aponeuroses & deep fat), extraperitoneal fat & parietal peritoneum
What is the fascia of the anterolateral wall?
- Subq tissue (fascia)- major fat storage; above umbilicus, subq consistent w/most areas of body
- Below umbilicus:
1. Superficial fascia (Camper fascia)
2. Deep membranous layer (scarpa fascia) [deep layer continuous inferiorly with superficial perineal fascia (colles fascia)
What does the investing fascia (epimysium) cover?
covers 3 muscles of the anterolateral wall & connects them to their respective aponeurosis
What is the transversalis fascia?
part of the “endoabdominal fascia” covering the inner aspect of the transversis abdominis muscle
What is the parietal peritoneum?
lines the entire abdominal cavity, internal to transversalis fascia separated by varying thicknesses of extraperitoneal fat
What are the categories of the anterolateral wall muscles?
five bilaterally paired muscles- 3 flat (2 diagonal, 1 transverse fibers) & 2 vertical
What are the flat muscles of the anterolateral abdominal wall muscles?
external oblique, internal oblique, & transverse abdominis
What are the vertical muscles of the anterolateral abdominal wall?
rectus abdominis & pyramidalis (in 80% of population)
What is the external oblique muscle?
- which fibers are the largest?
- which part contrubutes the most?
- largest & most superficial of the 3 flat abdominal muscles
- posterior most muscle fibers are thickest part of muscle
- fleshy (muscular) part contributes the most to lateral part of abdominal wall
What is the external oblique muscle?
- where does the aponeurosis contribute?
- which direction do fibers run?
- where is the inferior aponeurosis & where does it attach?
- aponeurosis contributes to anterior part of abdominal wall (starts ~MCL & spinoumbilical line)
- most fibers run in inferomedial direction
- inferior aponeurosis thickens as fibrous band b/t ASIS & pubic tubercle- inguinal ligament (poupart ligament) & attaches medially to linea alba
What is the internal oblique muscle?
- which direction do the fibers run?
- where do the fibers merge & what does the aponeurosis contribute to?
- middle layer of 3 flat muscles
- fleshy fibers run perpendicular to external oblique fibers; most fibers run superomedially
- fibers merge w/it’s aponeurosis ~MCL which contributes to formation of rectus abdominus sheath & connects medially to linea alba
What is the transversus abdominis muscle?
- which direction do the fibers run?
- where do the fibers originate & what do they merge with?
- what does it contribute to?
- innermost layer of flat muscles
- run “transversely”
- large portion of fibers originate from the thoracolumbar fascia posteriorly & merge w/anterior aponeurosis ~MCL
- contributes to posterior wall of rectus abdominus sheath
What is the rectus abdominus muscle?
- what is it paired with?
- where do muscle fibers anchor?
long/broad, strap-like vertical muscle from ribcage to pubic bone; flat & wide superiorly, narrow & thick inferiorly; most of body is within it’s sheath (formed by flat muscle neuroses)
- fibers anchor transversely with anterior layer of sheath at 3 or more tendinous insertions (6 pack)
What is the rectus sheath, linea alba, & umbilicus? What does it contain?
strong (yet incomplete) fibrous compartment for rectus abdominis muscles (also pyramidalis muscle if present) & also contains vessels, nerves, & lymphatics of anterolateral ab wall
How are the rectus sheath, linea alba, & umbilicus formed?
- formed by decussation & interweacing of the aponeuroses of flat ab muscles (external & internal obliques & transversus abdominis)
What forms the anterior and posterior walls of the rectus sheath?
What is the function of the internal oblique aponeurosis?
external oblique aponeurosis forms anterior wall og sheath its entire length & transversus abdominis aponeurosis forms posterior sheath wall
internal oblique (superior 2/3) splits into 2 layers (ant & pos); ant tissue joins external oblique aponeurosis to form anterior wall of sheath; pos tissue joins transversus abdominis aponeurosis to form pos sheath wall (stays this way until ~1/3 of way b/t umbilicus & pubis)
What are the dermatomes of the anterolateral wall?
anterior rami of spinal nerves T7-T12 following ribs as intercostal nerves & branching into thoracoabdominal nerves at the costal margins (overlap of nerves allows for inhury)
spinal nerve L1 branches as 2 nerves & supplies a larger area of pubic & proximal thigh
What are the lateral (thoracic) cutaneous nerve branches and where is it located?
anterolateral abdominal wall- branches of spinal nerves T7-T9 (or 10)
Where is the subcostal nerve located and where is it from?
anterolateral abdominal wall- from anterior ramus of T12
Where are the iliohypogastric & ilioinguinal nerves located and what branches do they form?
anterolateral ab wall- terminal branches of anterior ramus of spinal nerve L1
What covers the internal surface of the anterolateral abdominal wall?
internally- covered by transversalis fascia, varying amts of extraperitoneal fat, & PP
What are the folds of the parietal peritoneum?
5 infraumbilical, 2 supraumbilical
- infraumbilical: median, medial, & lateral
- supraumbilical: falciform ligament & round ligament
What are the fossae of the anterolateral wall?
supravesical fossae
medial inguinal fossae
lateral inguinal fossae
Where is the supravesical fossa?
lies between the median and medial infraumbilical folds (from umbilicus to bladder apex)
Where is the medial inguinal fossae located?
lies b/t medial and lateral infraumbilical folds; also called inguinal triangles (Hesselbach triangles)
Where is the lateral inguinal fossae located?
lies lateral to the lateral infraumbilical folds & includes the deep inguinal ring of the inguinal canal
Where is the inguinal region located and what descends through it?
“the groin” extends from the ASIS to the pubic tubercle (many structures enter & exit cavity here & it is a potential site of herniation)
male gonad (testis) descends through the inguinal canal (site of hernia) just prior to birth
Where is the inguinal ligament located?
spans from ASIS to pubic tubercle as a bilaminar “retinaculum” for the flexors of the hip joint & neurovascular structures- space called “subinguinal space”
What is the inguinal ligament formed from?
formed from the thickened inferolateral most portion of the external oblique aponeurosis
What is the lacunar ligament & what is the reflected inguinal ligament comprised of?
some deeper fibers of the external oblique aponeurosis pass posterior forming supporting structures (which is called lacunar ligament); some attach superiorly to linea alba & form reflected inguinal ligament
What is the iliopubic tract formed of and what is it’s function?
thickened inferior margin of transversalis fascia; forms a fibrous band running parallel but deep to inguinal ligament & reinforces the pos wall and floor of the inguinal canal
Where is the inguinal canal located and what does it contain?
~4cm long & directed inferomedially; runs parallel & superior to medial half of inguinal ligament
- contains spermatic cord (male) or round ligament of uterus (female) plus blood & lymphatic vessels & ilioinguinal nerve (both)
- canal has 2 walls (ant & pos) & roof & floor
Where is the deep (internal) inguinal ring located?
entrance to cancal through evagination of transversalis fascia; lateral to inferior epigastric artery
Where is the superficial (external) inguinal ring located?
(in inguinal canal)
exit for spermatic cord (M) or round lig (F) through split in external oblique aponeurosis just superolateral to pubic tubercle
What is the posterior abdominal wall composed of?
- five lumbar vertebrae (L1-L5)
- posterior wall muscles (psoas, iliacus, quadratus lumborum, transversus abdominis), & abdominal obliques (internal & external)
- fascia (including thoracolumbar fascia)
- lumbar plexus of nerves from anterior rami of lumbar spinal nerves
- fat, nerves, vessels (aorta, IVC), LN
What are the quadrants of the body?
What are the organs in the respective quadrants?
What are the origins, insertions, innervations, & main actions of the abdominal muscles?
What are the boundaries of the inguinal canal?
