10.23.96-----begin---------

Dr.Orsini remarks that our class is 6 pts above the average from last 
year. He says if you're above 60% right now, you're cool.

Today: we're going to do GI of the horse. ruminant stuff is still going 
to be up there on the R side of the lab. Horse stuff will be on the L. 
Tomorrow we'll start dissection of the thoracic limb.

The front limbs right now are in the coolers, still. 

There seems to be some anxiety building up, so to diffuse that...
p 168 smallwood - gigantic chapter on the tarsus. He likes that, because 
the hock is a big problem area for standardbreds. Horse lamenesses are 
generally in the hock and below or the carpus and below.  Now, honestly, 
the radiographs we aren't going to be held responsible for.

 P 169 table 7-1: just know the bones of the horse tarsus.

when we do the carpus, we'll have to know the carpal bones as well.

P 173: top section, talks about joints of the hock. we should know those 
terms. They try to give names we can relate to. 
 
With the stifle, don't worry which one communicates w/which, just know 
the names of the different levels.
know p 168, 169, 173, 198-200.

[diagrams]

metapodal bones are commonly broken.not very big bones, in fact. in 
horse, Mt3 is the one that supports body weight. splint bones (Mt 2,4) 
also fracture easily.

note that the book calls the tibiotarsal joint the tarsocrural joint. you 
don't have to memorize that name.

there are 4 levels of articulation in the hock. the tibiotarsal joint, 
proximal and distal intertarsal joints, and the tarsometatarsal joint. 
know those.

note that in ruminant. the metatarsal bone has a fused Mt3-Mt4, with a 
groove down the middle housing the dorsal pedal artery

re: blood supply
know the regional names
femoral---> popliteal--->cranial tibial
smallwood discusses it well, know the boldface on p 163.

know the nerves in bold, don't worry about stuff below medial and lateral 
plantar.

lateral/dorsal aspect of Mt4 has major artery to the foot.
know veins in general sense. know ruminant has lateral saphenous vein, 
horse has medial saphenous.

what about blood supply to GI system?
p 82 smallwood - know boldface minus exceptions as mentioned in class. 
don't bother dissecting these out, though.

TOPOGRAPHY in ruminant very important. if you need to get into a rumen to 
take out a nail, you MUST go in the LEFT side...very embarassing to go in 
the wrong side....So, get familiar with the topography.

diagrams.horse gi tract very poorly engineered, [diagrams]. the colon in 
dogs doesn't have many problems, but in horses, the ascending colon is 
very movable, because it isn't suspended well by its mesentery.

dorsal part of ascending colon is smooth walled, ventral part is 
sacculated.
the dorsal and ventral large colon are closely attached by mesentery 
(mesocolon). KNOW that the ventral colon is always sacculated. this is 
important in colic surgery. 
some parts of the colon have BANDS or TENIA. appreciate bands, but don't 
memorize how many bands are on each part of the colon. it makes no 
difference, won't be clinically important.

"follow the bouncing kernel of corn"...from small intestine into cecum.
the cecum is on the R side of the animal. corn will leave cecum and move 
out the right ventral ascending colon, across to the left into the left 
ventral ascending colon - goes caudally, then into left dorsal colon 
dorsally and cranially, then over into right dorsal colon, then into 
transverse colon, back over to the left, then into the descending colon.

think about these regional names. think about the vastness. note the 
flexures. the PELVIC FLEXURE of the ascending colon is back near the end 
of the descending colon. this can be palpated rectally.
feed impactions are common there.

-----end of lecture----