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orsini's announcements: tomorrow: start dissecting fresh limb. we'll have 
two days to do it. there IS a clinical correlation tomorrow: dr dean 
richardson from NBC. but we'll still have a chalk talk. BE at the talk at 
11 am on time. otherwise Dr. Richardson will yell at dr orsini. it's 
going to be in rm 13.
also...friday afternoon bet 4-5 in B101, there's a motion picture using 
the music of YES with racehorses in slow motion. (roundabout).

smallwood p 232 carpus
table 9-1 just know horse
radiographic anatomy of equine carpus p 234 skip to 238. p 238 has nice 
review. then skip bottom of 238 lateromedial view, and go to p 271. pick 
up on 271 and know the bold print. on 273: don't look for palmar 
metacarpal nerves. p 275 "other considerations" read the paragraph on 
blood supply, innervation pattern not important. on 276 skeletal anatomy 
of fetlock and digital region is important. p 294 "ligaments of digits in 
artiodactyls" has proximal and distal interdigital ligaments in bold. 
don't sweat it.

stay apparatus: passive relaxation of limb.
in forelimb
two accessory ligaments associated w/superficial digital flexor and deep 
dig flexor. sdf: proximal check ligament, ddf: distal check ligament.
in hindlimb you can't really see prox check lig. but in forelimb, it 
comes right off the radius. the distal check ligament comes of the caudal 
side of the carpal bones and is very thick and easier to see.

interosseus is also coming off caudal part of carpus and the caudal 
proximal metacarapal and is very closely adhered to the back of the 
metacarpal bones. it attaches distally to the abaxial side of the 
proximal sesamoid and branches dorsally - the extensor branch - to hook 
up to the common digital extensor tendon.

the DDF and SDF tendons continue distally past the proximal sesamoids. 
the palmar annular ligament attachs to the abaxial surfaces of the 
sesamoids and covers the carpal canal. distally are the x shaped proximal 
digital annular ligament, which attaches at the proximal and distal 
tubercles of Pi, and the distal digital annular ligament which is just 
proximal to and inserts on the hoof - so it attaches to bumps in the 
middle of Pi and covers Pii, then goes all the way down to the hoof (?).

in most animals, superficial digital flexor inserts only on Pii. in 
horse, inserts on Pi and Pii. note that at the crossover point, the SDF 
tendon forms a sleeve around the DDF

prox ses and Pi help form a sling to keep McIII from going to floor. 

another part of suspensory apparatus is the sesamoidean ligamenture.

all arise from distal surface of proximal sesamoid

note: deep to palmar annular ligament is the intersesamoidean ANNULAR 
LIGAMENT. there are also collateral ligaments binding the sesamoids to 
McIII laterally.

sesamoidean ligs:

straight: axial. attaches to Pii at the complementary fibrocartilage of 
Pii and the smooth surface of Pii which together make up the scutum.

also: oblique sesamoidian ligaments, cruciates: go to Pi only. there is 
kind of a triangle on the bone where the oblique ligs attach. the 
cruciates have a small x shape to them. they are very deep, and go from 
proximal ses on one side to other side of Pi, so they make an x when you 
see both of them. p 277 smallwood has a picture. so, when 
metacarpophalangeal joint is extended, prox ses drops down. prox 
interphalangeal joint stays fixed. flexors and CDE work as antagonists to 
keep the distal limb stable.

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