Anatomy- Bones, Tendons, and Ligaments Flashcards
what is the horse equivalent of our knee?
carpus
what is the horse equivalent of our heel?
hock
list the 3 major joints in the lower leg, working top to bottom
- fetlock
- pastern
- coffin
what bones are found in the carpus?
metacarpals (2,3,4)
what bones are found in the hock?
metatarsals
what is metacarpal 3 also called?
cannon bone
what is metacarpal 2 also called?
medial splint bone
what is metacarpal 4 also called?
lateral splint bone
what are the 4 hella important tendons and ligaments in the lower leg of the horse?
- superficial digital flexor tendon (SDFT)
- deep digital flexor tendon (DDFT)
- proximal suspensory ligament
- suspensory ligament
what do tendons attach?
attach muscle to bone
describe elasticity of tendons
relatively inelastic
initiated by what, what do tendons do?
initiated by muscle contraction (via nerves), tendons exert pull on skeleton
what is another name for tendon?
strong extension of muscle
describe tendons compared to muscle
rigid compared to muscle
what do tendons and muscles work together to do? (3)
- allow movement
- accomodate stretch
- bear weight
what holds tendons in position?
annular ligaments
what are annular ligaments? what do they do?
connective tissue that keeps tendons in proper track
what are tendons surrounded by?
tendon sheaths
what is the function of tendon sheaths? (2)
- prevent damage to tendon
- contains synovial fluid, which reduces friction during movement, further preventing damage
where do ligaments originate from and attach to?
from bone to bone
what do ligaments do?
keep bones in alignment
compare ligament elasticity to tendons
ligaments are even less elastic than tendons
describe the suspensory ligament (4)
- differs from other ligaments; is a “modified muscle”
- contains some msucle/tendinous tissue
- has considerable elasticity compared to other ligaments
- tries to protect fetlock while still allowing movement
where is the suspensory ligament found?
runs next to the cannon bone underneath other tendons and ligaments; then splits and encircles the sesamoids
what is the primary role of the suspensory ligament?
stability
what 2 tendons are found on the front of the cannon bone? describe them
- lateral digital extensor tendon
- common digital extensor
these are flat and closely related
what 2 tendons are found on the back of the cannon bone?
- superficial deep digital flexor tendon (SDFT)
- deep digital flexor tendon (DDFT)
where is the inferior check ligament? where does it originate? what does it fuse with?
- between the suspensory ligament and the flexor tendons (NOT BONE TO BONE)
- originates on the third metacarpal/carpal joint
- fuses with DDFT
where does the Superior check ligament originate? what does it fuse with?
- originates on back surface of radius
- fuses with SDFT
what are the 3 pastern bones also called?
p1 = long pastern
p2 = short pastern
p3 = coffin bone (in hoof)
describe the location/splitting of the SDFT and DDFT
- both tendons run down back of leg in synovial sheath
- then at the lower end of the cannon, the SDFT flattens and widens to form a ring surrounding the DDFT
- the DDFT then runs through the SDFT ring behind the fetlock, surrounded by a synovial sheath
- below the fetlock, the SDFT divides into 2 parts
what does each branch of the SDFT insert into below the fetlock?
each branch inserts on either side of the lower long pastern bone and upper short pastern bone
what does the DDFT attach to once it runs down the bifurcation of the SDFT? what does it then cross underneath?
attaches to the bottom of the coffin bone; crosses underneath navicular bone
what is the navicular bone?
the distal sesamoid bone
what does the navicular bursa lie between?
the DDFT and the navicular bone
where does the suspensory ligament lie?
in the metacarpal groove created by cannon and splint bones
what is the suspensory ligament?
a wide thick band that originates on the upper back surface of the cannon bone and on the lower row of the carpal bones
where does the suspensory ligament divide into two branches?
at the lower quarter of the cannon
what does each branch of the suspensory ligament pass to and then what happens?>
each branch passes to the outside face of the corresponding sesamoid bone, where a large segment of the ligament attaches, nearly encasing the bone
what happens to the rest of the suspensory ligament that does not attach to a sesamoind bone face?
the rest of the ligament passes downwards and forward to the front surface of the long pastern, where it merges with the common digital extensor tendon
compare the suspensory ligamentto other ligaments and say why
more elastic than other ligaments because it contains tendinous tissue
what is the main function of the suspensory ligament (other than general stability role)
supporting the fetlock and guarding it against extreme hyperextension
what do the two branches of the suspensory ligament that join the common digital extensor tendon do?
limit extreme flexion of the pastern joint
