Hock & Distal Limb Muscles Flashcards
what type of bones are in the tarsus
tarsal bones
short bones
what bones are in the proximal, middle, distal row of the tarsus
proximal: talus, calcaneus - palpable
middle row: central & 4th TBs
distal row: 1, 2, 3 & 4 TBs (4th TB bridges middle and distal rows)
which tarsal bones are fused in the horse
1 and 2
3 very large
what are the joints in the tarsus
- tibio-tarsal joint
- proximal intertarsal joint
- distal intertarsal joint
- tarso-metatarsal joint
what is the tibio-tarsal joint
talus-tibia & fibula
large range of movement
calcaneus –> not articular (lever to move distal limb)
2 trochlear ridges
what is the proximal intertarsal joint
talus and calcaneus
central and 4 TBs
what is the distal intertarsal joint
central 1, 2, & 3 TBs (4th bridges the joint, no movement)
what is the tarso-metatarsal joint
1, 2, 3, & 4 TBs - metatarsal bone
firmly attached –> no movement
intratarsal joints –> ligaments holding bones together
name the joints of the tarsus
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- tibio-tarsal joint
- proximal intertarsal joint
- distal intertarsal joint
- tarso-metatarsal joint
what is the movement in the tarsus
large range of flexion
most movement in the tibio-tarsal joint
little movement in other joints
what produces rotation in the tarsus
trochlea not verticle
what occurs during limb protraction and hock flexion
distal hindlimb directed lateral to forelimbs
prevents over reach injuries
what occurs during limb retraction and hock extension
distal hindlimb directed in axial plane –> propulsion
what are the features of the tarsus
typical synovial joint
extensive joint capsule
poor communication between compartments
what is palpable within the tarsus
tibio-tarsal joint separate from rest
dorsomedial aspect, plantarolateral aspect, plantaromedial aspect
distal reigions of joint –> dorsomedial and dorsolateral aspect
how is the tarsus stabilized
- collateral ligaments
- fibrocartilagenous reinforcement of joint capsule
- retinaculum
- plantar ligament
how does the collateral ligament stabilize the tarsus
ligaments on
long: tibia- metatarsal bone
short: bridge bone - bone
common injury in dressage and cow horses
what ligaments and structures are shown
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- collateral ligaments
- fibrocartilagenous reinforcement of joint capsule
what ligament is this
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plantar ligament
how many centres of ossifications do the tarsal bones develop from
all single
except the calcaneus bone = 2
what are clinical conditions of the tarsus
- bone spavin = hock degereative joint disease
- central & 3rd TBs most commonly affected
- new bone formation
- joints may fuse - no longer visible on radiograph
- if affects tibio-tarsal joint = very bad prognosis
what clinical condition is shown
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bone spavin
what are the origins and insertions of the cranial tibial muscle
O- proximal tibia
I- metatarsal bones (all sp.)
I- medial aspect hock (horse) = cunean tendon
what is the function of the cranial tibial muscle
hock flexion
what is the nerve supply of the cranial tibial muscles
peroneal/fibular nerve (branch of sciatic)
what muscle
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cranial tibial muscle
what muscle
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cranial tibial muscle
what is the origin and insertion of the peroneus longus/long fibular muscle
O- lateral tibia and fibula
I- plantar aspect tarsus
do horses have the peroneus longus/long fibular muscle
no only dogs and cats
what are the origin and insertions of the peroneus tertius/third fibular muscle
O-lateral femoral condyle (with long digital extensor muscle)
I- 3rd MT (with cranial tibial muscle)
I- lateral aspect tarsus
what is the function of the peroneus muscle
hock flexion
what is the nerve supply of the peroneus muscle
peroneal/fibulra nerve (branch of sciatic)
what muscle
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peroneus longus/long fibular muscle (dog & cat)
peroneus tertius/third fibular muscle (horses)
what is the origin and insertion of the long digital extensor muscle
O- extensor fossa (femur)
tendon of origin incorperated into stifle joint capsule –> provides lateral collateral support to stifle
I- all digits
distal phalanx –> extensor process
what is the function of the long digital extensor muscle
hock flexion
digital extension
what are the nerve supply of the long digital extensor muscle
peroneal/fibular nerve (branch of sciatic)
what muscle is this
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long digital extensor muscle
what tendon is present on the distal caudal aspect of the hindlimb
common calcanean tendon (achilles tendon)
what are the components of the common calcanean tendon
- biceps femoris
- semitendinosus
- gracilis
- gastrocnemius
- superficial digital flexor
what is the insertion of the common calcanean tendon
I- calcaneus
tuber calcis/calcanean tuberosity
what is the function of the common calcanean tendon
acts as lever for distal limb + plantar ligament
hock extension
what tendon is this
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common calcanean tendon
what tendon and ligament is this
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common calcanean tendon
plantar ligament
what are the origin and insertion of the gastrocnemius muscle
O- femur
(2 tendons of origin, fabellae)
I- calcaneus
(most significant component of common calcanean tendon)
what is the function of the gastrocnemius muscle
hock extensor
(stifle flexor)
what is the nerve supply to gastrocnemius muscle
tibial nerve (branch of sciatic)
what muscle is this
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gastrocnemius muscle
what are the origin and insertion of the superficial digital flexor muscle
O- distal femur (with gastrocnemius)
I- calcaneus (part of common calcanean tendon)
I- branches to all digits (middle phalanx)
what is the function of superficial digital flexor muscle
hock extension
digital flexion
support of distal limb joints in extension (no accessory check ligament)
what is the nerve supply of the superficial digital flexor muscle
tibial nerve (branch of sciatic)
what muscle is this
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superficial digital flexor muscle
what is the origin and insertion of deep digital flexor muscle
O-tibia (runs over tarsus, not part of common calcanean tendon)
I- branches to all digits (distal phalanx)
what is the function of the deep digital flexor muscle
hock extensor
digital flexor
support of dital limb joints in extension
weak accessory check ligament (small, or completely absent)
what is the nerve supply to the deep digital flexor muscle
tibial nerve (branch of sciatic)
what muscle is this
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deep digital flexor muscle
what muscles are hock flexors
- cranial tibial muscle
- peroneus muscle
what muscles are hock flexor and digital extensor
long digital extensor
what nerves are the hock flexors supplied by
fibular/peroneal nerve
what muscles are hock extensors +/- digital flexors
- common calcanean tendon (biceps femoris, semitendinosus, gracilis, gastrocnemius, superficial digital flexor)
- deep digital flexor
what nerves supply the hock extensors
tibial nerve
which tendon is palpable
common calcanean tendon
what is the hindlimb stay apparatus allowing
natural weightbearing position = extension
ability to lock weight bearing hindlimb in extension while other rested (resting forelimb = lame)
what does the hip/stifle/hock prevent
collapse into flexion
what system does the hip have in the hindlimb stay apparatus
no passive system
what system does the stifle have in the hindlimb stay apparatus
patellar locking mechanism
what system does the hock contain in the hindlimb stay apparatus
reciprocal apparatus
what is the reciprocal apparatus
peroneus tertius
superficial digital flexor
fibrous bands (not really a muscle –> acts as a rope)
what is the proximal movement of origin in the reciprocal apparatus
proximal movement of insertion
stifle and hock must move together
what system is shown here
reciprocal apparatus
peroneus tertius & superficial digital flexor
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what do the MTP/PIP/DIP joints prevent
hyperextension
what does the MTP joint contain that contributes to the stay apparatus
suspensory apparatus
suspensory ligament
proximal sesamoids
distal sesamoidean ligaments
long digital extensor
what do the MTP, PIP, DIP joints contain that contributes the the hindlimb stay apparatus
SDFT (no accessory check ligament)
DDFT + accessory check ligament
annular ligaments
what is the functional significance of the hindlimb in horses
massive power during hindlimb extension
huge muscle mass –> gluteal muscles, hip extensors/limb retractors (extra heads), stifle extensors, hock extensors (reciprocal apparatus)
forces directed caudally in axial plane (angled trochlea on talus –> jumping)
what are the palpable swellings around the tarsus
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- joint effusion (5 locations)
- seroma (capped hock)
- bursitis (calcanean bursa)
- tendon sheath effusion
- plantar ligament - “curb”
- distended medial saphenous vein
identify the muscles and tendons
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identify the muscles and tendons
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identify the muscles and tendons
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identify the muscles and tendons
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identify the muscles and tendons
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identify the tendons and muscles
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identify the equine hock bones
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identify the components of the canine hock
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