Anatomy of the Equine Gastrointestinal System (Part 1) - Dr. Masty

Flank

topographic region of abdominal wall from ribs to ________

________ of the flank

skin and cutaneous trunci reflecting onto thigh

Paralumbar fossa

hollow area of the flank

Cranial boundary of the flank

Caudal boundary of the flank

Ventral boundary of the flank

Innervation of the flank

lateral cutaneous branches of __________ and branches of thoracic and lumbar spinal nerves

Five nerves of the flank:

1.) costoabdominal nerve

2.) iliohypogastric nerve

3.) ilioinguinal nerve

4.) genitofemoral nerve

5.) lateral cutaneous femoral nerve

costoabdominal nerve

thoracic nerve #

location of the costoabdominal nerve

costrochondral junction of rib 18

iliohypogastric nerve

L1

ilioinguinal nerve

L1

location of the ilioinguinal nerve

v

genitofemoral nerve

lumbar nerve #

lateral cutaneous femoral nerve

L4

location of the lateral cutaneous femoral nerve

subiliac lymph node with caudal branches of deep circumflex iliac artery

Skin of the abdominal wall

umbilicus located on ________

midline incision of the abdominal wall

cuts through _________

paramedian incision of the abdominal wall

cuts through _________

Five muscles of abdominal wall

1.) cutaneous trunci

2.) external abdominal oblique

3.) internal abdominal oblique

4.) transversus abdominis

5.) rectus abdominis

Cutaneous trunci muscle

sheet of muscle immediately deep to the skin

cutaneous omobrachialis

cutaneous muscle of the shoulder

External abdominal oblique muscle

muscle and aponeurosis; covered by abdominal tunica (aka tunica flava abdominus)

Three features of the external abdominal oblique muscle:

1.) caudo _________ fibers

2.) inguinal ligament

3.) __________ inguinal ring

4.) part of the ___________ sheath of the rectus abdominus muscle

inguinal ligament

________ edge of external abdominal oblique muscle

__________ inguinal ring

v

heave line

clinical condition known as "Heaves"; hypertrophy of muscular position of external abdominal oblique in emphysema

Two features of internal abdominal oblique muscle:

1.) cranio ___ fibers

2.) part of _______ sheath of the rectus abdominus msucle

Three features of transversus abdominus:

1.) all of _______ sheath of the rectus abdominus

2.) _________ fibers

3.) cranial branch of deep circumflex iliac artery

Three features of rectus abdominus:

1.) _________ tendon

2.) tendinous intersections, no aponeurosis

3.) covered by _________ and _________

Three ingional canal structures

1.) superfical inguinal ring

2.) deep inguinal ring

3.) vaginal ring

superfical inguinal ring

natural slit in apopneurosis of ____

deep inguinal ring

formed by edges of __________ abdominal oblique as it is positioned deep to the inguinal ligament

vaginal ring

peritoneal lining over _______ inguinal ring

Total path through the large intestine:

cecum --> ascending colon --> transverse colon --> small colon --> rectum --> anal canal --> anus

cecum

comma shaped, initial segment of the large intestine where fermentation occurs

The ascending colon is the _________ segment of the equine large intestine

longest

Model for the structure of the ascending colon

two "U"s on top of each other, connected on the left side of the body

The ascending colon is broken up into four segments:

1.) right ventral colon

2.) left ventral colon

3.) left dorsal colon

4.) right dorsal colon

Three flexures of the ascending colon:

1.) sternal flexure

2.) pelvic flexure

3.) diaphragmatic flexure

sternal flexure of the ascending colon

bend between the right ventral and left ventral quadrants (right to left)

pelvic flexure of the ascending colon

bend between the left ventral and left dorsal quadrants (ventral to dorsal)

diaphragmatic flexure of the ascending colon

bend between the left dorsal and right dorsal quadrants (left to right)

right ventral colon

1

sternal flexure

2

left ventral colon

3

pelvic flexure

4

left dorsal colon

5

diaphragmatic flexure

6

right dorsal colon

7

transverse colon

C

Transverse colon

shortest segment of the large intestine

The descending colon is aka...

the small colon

*due to its smaller diameter compared to the other segments of the large intestine

Two features of the small colon:

1.) bands

2.) sacs

bands of the small colon

strips of muscle along various segments of the small/descending colon

anatomic term for "bands"

tiniae coli

sacs of the small colon

pouches of the small/descending colon on the surface

anatomic term for "sacs"

haustra

The small colon changes names to the rectum at the level of the...

pelvic inlet

anal canal

terminal segment of the large intestine

anus

opening of the large intestine

The abdominal contents are located inside the _______ of the diaphragm

dome

The diaphragm bulges forward to the level of rib ____

rib 6

The abdominal cavity is divded into three compartments based on two lines spanning from...

1.) the tuber coxae to the elbow

2.) the tuber coxae to the umbilicus

Five abdominal organs located on the left side:

1.) liver

2.) stomach

3.) spleen

4.) left dorsal colon

5.) left ventral colon

liver topographic location on the left side

7-9 ribs, high compartment

stomach topographic location

9-15 ribs, high compartment

base of the spleen topographic location

15-18 ribs, high compartment

apex of the spleen topographic location

9-12 ribs, mid compartment

left dorsal colon topographic location

mid compartment, dorsal to the left ventral colon

What will be present located cranially on the left dorsal colon?

diaphragmatic flexure

left ventral colon topographic location

low compartment, ventral to the left dorsal colon and touching the ventral wall of the abdominal cavity

What will be present located cranially on the left ventral colon?

sternal flexure

Two abdominal organs in the middle of the abdominal cavity:

1.) small intestine

2.) descending/small colon

Which segments of the small intestine are in the middle of the abdominal cavity?

jejunum and ileum

Five abdominal organs located on the right side:

1.) liver

2.) descending duodenum

3.) right dorsal colon

4.) right ventral colon

5.) cecum

liver topographic location on the right side

between ribs 7-16, high compartment

descending duodenum topographic location

under the ribs, high compartment; does not go past the last rib into the paralumbar fossa!

right dorsal colon topographic location

dorsal to the right ventral colon, mid compartment

right ventral colon topographic location

ventral to the right dorsal colon, low compartment contacting the ventral body wall

The cecum is broken into three sections:

1.) base

2.) body

3.) apex

base of the cecum topographic location

right paralumbar fossa

body of the cecum topographic location

against flank

apex of the cecum topographic location

going craniomedially toward the midline (toward the left)

liver

1

stomach

2

spleen

3

diaphragmatic flexure of left dorsal colon

4

sternal flexure of left ventral colon

5

liver

1

descending duodenum

2

base of cecum

3

body of cecum

4

apex of cecum

5

right dorsal colon

6

right ventral colon

7

The root of the mesentery is at the level of which vertebra in the horse?

L1

Topographic location of the right kidney

level of T16-18, L1

Topographic location of the left kidney

level of T18, L1-L3

Topographic location of the ovaries

half way between the tuber coxae and the last rib