Dissection XI: Abdominal Body Wall

Question 1

What are the bony landmarks of the abdominal cavity?

Answer 1

Abdominal cavity is formed by muscles of the abdominal wall, ribs, crainially the boundaries are the bony attachments of the diaphragm (bodies of 3rd and 4th lumar vertebrea; medial surface of 8-13th ribs, dorsal surface of sternum cranial to xiphoid cartilage) and lined by peritoneum which encloses the peritoneal cavity

Question 2

What are the landmarks of the peritoneal cavity?

Answer 2

closed space lined by serous membranes, parietal peritoneum lines the body wall visceral peritoneum surrounds all the organs of the abdominal cavity; connecting peritoneum extends between the parietal and visceral peritoneums and forms a mesentery that suspends the organs of the abdominal cavity and contains their blood vessels and nerves

Question 3

pelvic inlet

Answer 3

marks the boundary between abdominal cavity and pelvic cavity limited laterally and ventrally by the arcuate line of the ilium, dorsal boundary is the promontory of the sacrum

Question 4

pelvic outlet

Answer 4

bonded ventrally by ischiatic arch mid dorsally by first caudal vertebrea and laterally by superficial gluteal muscle, muscles of the pelvic diaphragm, and the sacrotuberous ligament

Question 5

coccygeus muscle

Answer 5

attachments: ischiatic spine to transverse process of caudal vertebrea 2-4

Question 6

Levator ani muscle

Answer 6

medial to coccygeus muscle; medial edge of shaft of ilium and the dorsal surface of pubis and pelvic symphysis to caudal vertebrea 3-7

Question 7

pelvic diaphragm

Answer 7

formed by coccygeus muscle and levator ani muscle (forms muscular boundary for caudal extent of pelvic cavity)

Question 8

femoral artery

Answer 8

runs to hindlimb through femoral triangle

Question 9

abdominal and peritoneal cavity interfaces

Answer 9

femoral triangle and inguinal canal

Question 10

what passes through inguinal canal

Answer 10

provides passage of external pudenal vessels, gentiofemoral nerve, and in the male the spermatic cord from abdomen to more superficial inguinal structures

Question 11

peritoneum

Answer 11

contains closed serous cavity in abdomen

Question 12

retroperitoneal

Answer 12

organs that develop deep to the parietal peritoneum and remain firmly attached to the body wall; these are NOT invested in a visceral peritoneum

Question 13

superfical inguinal ring

Answer 13

slit in aponeurosis of external abdominal oblique muscle, spermatic cord (males) and vaginal process (females) runs through this

Question 14

spermatic cord and vaginal processes

Answer 14

these are peritoneal outpocketings that emerge from superfical inguinal ring as they leave inguinal cavity

Question 15

caudal superfical epigastric artery

Answer 15

vessesl supplying caudal ventral abdonimal body wall (emerges from superfical inguinal ring)

Question 16

4 pairs of muscles of abdominal wall

Answer 16

external abdominal oblique, internal abdonial oblique, transversus abdominus, rectus abdominus

Question 17

prepubic tendon

Answer 17

runs from iliopubic eminence on the side of the pelvis to the iliopubic eminence on the other side

Question 18

linea alba

Answer 18

midventral raphe extending from xiphoid process to caudal attachment on symphysis pelvis via prepubic tendon, transversus abdominus, internal and external abdonimal obliques attach to this

Question 19

relationship of abdonimal wall muscles superficial to deep

Answer 19

external abdonimal oblique, internal abdonimal oblique, rectus abdominus, transversus abdominus

Question 20

transverse body axis

Answer 20

for flexion/ extension

Question 21

dorsal/ ventral body axis

Answer 21

for lateral bending

Question 22

longitudinal axis

Answer 22

for torsion (twisting)

Question 23

paralumbar surgical approach

Answer 23

should encounter external abdominal oblique, internal abdominal oblique, and transversus abdominis muscles, and transversalis fascia adherent to parietal peritoneum

Question 24

ventral surgical approach (abdominal)

Answer 24

layers you should encounter are external sheath of the rectus abdominus, rectus abdominus, and internal sheath of rectus abdominus, and the peritoneum

Question 25

external rectus sheath

Answer 25

formed by combined aponeuroses of the internal and external abdominal oblique muscles

Question 26

internal rectus sheath

Answer 26

formed by the aponeurosis of the transversus abdominis; internal abdominal oblique also contributes to internal sheath cranially

Question 27

linea alba surgical approach

Answer 27

only cut connective tissue layer so it is much easier to close (aponeurosis of extneral abdominal oblique, internal abdominal oblique, and transversus abdominis muscle

Question 28

external abdominal oblique muscle

Answer 28

arises from lateral aspects of last ribs and from thoracolumbar fascia; attaches to linea alba (medial crus) and pelvic brim (lateral crus); aids in expiration, urination, defecation, and parturition, flexion of the vertebral column when other muscles contract, lateral bending of vertebral column; fibers run caudoventrally

Question 29

vaginal process in males

Answer 29

leaves abdomen and infolds surrounding the testicular artery, vein, nerve, and ductus deferens

Question 30

internal abdominal oblique

Answer 30

arises with external abdominal oblique from thoracolumbar fascia caudal to last rib, attaches to linea alba; fibers run cranioventrally; aids in compression and support of abdominal viscera; fibers run cranioventrally

Question 31

abdominal body wall innervation

Answer 31

innervated by caudal intercostal nerves and by ventral branches of lumbar spinal nerves

Question 32

blood supply of abdominal body wall

Answer 32

• cranial epigastric artery (comes from internal thoracic artery, a branch of subclavian arteries)
• cranial abdominal artery (comes from common cranial abdominal/ caudal phrenic trunk, a branch of the aorta)
• caudal epigastric artery (from pudendoepigastric trunk off the deep femoral artery, a branch of external iliac artery)
• deep circumlfex iliac artery (from the aorta)

Question 33

rectus abdominus

Answer 33

attaches by aponeurosis to first few ribs and from sternum; attaches caudally on pelvic brim forming prepubic tendon; in abdominal region covered by rectus sheath superficially and covered by aponeurosis of transversus abdominus on deep surface; action: expiration, urination, defication, and parturition; supports abdominal viscera to bring pelvis cranial; flexion of the trunk

Question 34

Transversus abdominus

Answer 34

attaches to medial surface of last few ribs and to transverse process of lumbar vertebrea, fibers run transversely to attach to aponeurosis of linea alba; * in pubic region aponeurosis becomes superfical to the rectus*; compression and support of abdominal viscera

Question 35

deep inguinal ring

Answer 35

external pudental artery and gentiofemoral nerve emerge from deep inguinal ring; these supply inguinal and caudal abdominal mammae in female and scrotum in male

Question 36

external pudental artery cow

Answer 36

main blood supply to the udder

Question 37

main surgical approaches to peritoneal cavity

Answer 37

ventrally through linea alba, laterally through flank incision, or over inguinal rings

Question 38

flank incisions

Answer 38

done in grid approach where muscles are cut or separated in their given fiber directions (entry to abdomen where the 3 incisions or separation lines cross (caudoventrally through external abdominal oblique, cranioventrally through interal abdominal oblique, and transversely through transversus abdominus)

Question 39

incision over superfical inguinal rings

Answer 39

done to locate and remove cryptorchid testicle; if testicle not in inguinal canal a gubernaculum (fetal strcture that attaches to caudal pole of each testicle) may be located within the canal and can often be followed into the abdomen to find the testicle