Anatomy

Question 1

What is in the superior border (roof) of the abdominopelvic cavity?

Answer 1

diaphram, ribcage (attaches at ribs 7-10 & xyphoid)

Question 2

What is in the inferior border (floor) of the abdominopelvic cavity?

Answer 2

pelvic bones (ileum, ischium, & pubis [pairs] & pelvic diaphragm

Question 3

What is included in the posterior wall of the abdominopelvic cavity?

Answer 3

lumbar spine, quadratus lumborum, & spinal muscles

Question 4

What is included in the anterolateral walls of the abdominopelvic cavity?

Answer 4

musculoponeurotic layers (multiple)

Question 5

What are the boundaries of the anterolateral abdominal wall?

Answer 5

• Superiorly- 7th-10th ribs & xyphoid
• Inferiorly- inguinal ligament & rim of pelvis (ilac crest, pubic crest, & pubic symphysis)

Question 6

What does the anterolateral wall consist of?

Answer 6

skin, subq, muscles (& their aponeuroses & deep fat), extraperitoneal fat & parietal peritoneum

Question 7

What is the fascia of the anterolateral wall?

Answer 7

• 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)

Question 8

What does the investing fascia (epimysium) cover?

Answer 8

covers 3 muscles of the anterolateral wall & connects them to their respective aponeurosis

Question 9

What is the transversalis fascia?

Answer 9

part of the “endoabdominal fascia” covering the inner aspect of the transversis abdominis muscle

Question 10

What is the parietal peritoneum?

Answer 10

lines the entire abdominal cavity, internal to transversalis fascia separated by varying thicknesses of extraperitoneal fat

Question 11

What are the categories of the anterolateral wall muscles?

Answer 11

five bilaterally paired muscles- 3 flat (2 diagonal, 1 transverse fibers) & 2 vertical

Question 12

What are the flat muscles of the anterolateral abdominal wall muscles?

Answer 12

external oblique, internal oblique, & transverse abdominis

Question 13

What are the vertical muscles of the anterolateral abdominal wall?

Answer 13

rectus abdominis & pyramidalis (in 80% of population)

Question 14

What is the external oblique muscle?

• which fibers are the largest?
• which part contrubutes the most?

Answer 14

• 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

Question 15

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?

Answer 15

• 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

Question 16

What is the internal oblique muscle?

• which direction do the fibers run?
• where do the fibers merge & what does the aponeurosis contribute to?

Answer 16

• 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

Question 17

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?

Answer 17

• 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

Question 18

What is the rectus abdominus muscle?

• what is it paired with?
• where do muscle fibers anchor?

Answer 18

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)

Question 19

What is the rectus sheath, linea alba, & umbilicus? What does it contain?

Answer 19

strong (yet incomplete) fibrous compartment for rectus abdominis muscles (also pyramidalis muscle if present) & also contains vessels, nerves, & lymphatics of anterolateral ab wall

Question 20

How are the rectus sheath, linea alba, & umbilicus formed?

Answer 20

• formed by decussation & interweacing of the aponeuroses of flat ab muscles (external & internal obliques & transversus abdominis)

Question 21

What forms the anterior and posterior walls of the rectus sheath?

What is the function of the internal oblique aponeurosis?

Answer 21

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)

Question 22

What are the dermatomes of the anterolateral wall?

Answer 22

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

Question 23

What are the lateral (thoracic) cutaneous nerve branches and where is it located?

Answer 23

anterolateral abdominal wall- branches of spinal nerves T7-T9 (or 10)

Question 24

Where is the subcostal nerve located and where is it from?

Answer 24

anterolateral abdominal wall- from anterior ramus of T12

Question 25

Where are the iliohypogastric & ilioinguinal nerves located and what branches do they form?

Answer 25

anterolateral ab wall- terminal branches of anterior ramus of spinal nerve L1

Question 26

What covers the internal surface of the anterolateral abdominal wall?

Answer 26

internally- covered by transversalis fascia, varying amts of extraperitoneal fat, & PP

Question 27

What are the folds of the parietal peritoneum?

Answer 27

5 infraumbilical, 2 supraumbilical - infraumbilical: median, medial, & lateral - supraumbilical: falciform ligament & round ligament

Question 28

What are the fossae of the anterolateral wall?

Answer 28

**supravesical fossae** **medial inguinal fossae** **lateral inguinal fossae**

Question 29

Where is the supravesical fossa?

Answer 29

**lies between the median and medial infraumbilical folds (from umbilicus to bladder apex)**

Question 30

Where is the medial inguinal fossae located?

Answer 30

**lies b/t medial and lateral infraumbilical folds; also called inguinal triangles (Hesselbach triangles)**

Question 31

Where is the lateral inguinal fossae located?

Answer 31

**lies lateral to the lateral infraumbilical folds & includes the deep inguinal ring of the inguinal canal**

Question 32

Where is the inguinal region located and what descends through it?

Answer 32

"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

Question 33

Where is the inguinal ligament located?

Answer 33

spans from ASIS to pubic tubercle as a bilaminar "retinaculum" for the flexors of the hip joint & neurovascular structures- space called "subinguinal space"

Question 34

What is the inguinal ligament formed from?

Answer 34

formed from the thickened inferolateral most portion of the external oblique aponeurosis

Question 35

What is the lacunar ligament & what is the reflected inguinal ligament comprised of?

Answer 35

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

Question 36

What is the iliopubic tract formed of and what is it's function?

Answer 36

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

Question 37

Where is the inguinal canal located and what does it contain?

Answer 37

~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

Question 38

Where is the deep (internal) inguinal ring located?

Answer 38

**entrance to cancal through evagination of transversalis fascia; lateral to inferior epigastric artery**

Question 39

Where is the superficial (external) inguinal ring located?

Answer 39

(in inguinal canal) exit for spermatic cord (M) or round lig (F) through split in external oblique aponeurosis just superolateral to pubic tubercle

Question 40

What is the posterior abdominal wall composed of?

Answer 40

1. five lumbar vertebrae (L1-L5) 2. posterior wall muscles (psoas, iliacus, quadratus lumborum, transversus abdominis), & abdominal obliques (internal & external) 3. fascia (including thoracolumbar fascia) 4. lumbar plexus of nerves from anterior rami of lumbar spinal nerves 5. fat, nerves, vessels (aorta, IVC), LN

Question 41

What are the quadrants of the body?

Answer 41

Question 42

What are the organs in the respective quadrants?

Answer 42

Question 43

What are the origins, insertions, innervations, & main actions of the abdominal muscles?

Answer 43

Question 45

What are the boundaries of the inguinal canal?

Answer 45