Equine Hindlimb Flashcards
What are the 6 joints of the hindlimb?
- Hip
- Stifle
- Hock
- Fetlock
- Pastern
- Coffin
Hip joint
Btwn acetabulum and the head of the femur
What are the two stifle joints?
- Femoro-patellar (femur + patellar)
- Femoro-tibial (femur + tibia, fibula)
What are the 4 hock/tarsal joints?
- Tibio-tarsal (tarsocrual)
- Proximal intertarsal (centroproximal)
- Distal intertarsal (centrodistal)
- Tarsometatarsal
Tibiotarsal (tarsocrual) joint
Btwn distal end of the tibia and the first proximal row of the tarsal bones (talus and calcaneus)
Proximal intertarsal joint (centroproximal)
Btwn talus/ calcaneus and the second row of tarsal bones (central and 4th tarsal bones)
Distal intertarsal joint (centrodistal)
Btwn central tarsal bone and distal row of tarsal bones
Fused 1st and 2nd tarsal bones and the 3rd and 4th tarsal bones
Tarsometatarsal
Btwn distal row of tarsal bones (1,2,3 and 4 tarsal bones) and the 2nd, 3rd, and 4th metatarsal bones
Fetlock joint
Btwn the distal end of the 3rd metatarsal and the proximal sesamoid bones and P1
Pastern joint
Btwn P1 and P2
Coffin joint
Btwn the P2/P3 (coffin bone) and distal sesamoid bone (navicular bone)
Which muscles extend the hip?
Semimembranosus, semitendinosus, superficial and middle gluteal
CS of the semimembranosus and semitendinosus
IM injections
alternate muscles so you won’t give abscess
What is the function of the biceps femoris?
Extends and abducts the limb
What is the function of the deep gluteal muscle?
Abducts the limb
What is the function of the quadriceps?
Extend the stifle
What is the function of the gracilis?
Adduct the limb
Trochanteric bursa
Formed by the tendon of insertion of the middle gluteal muscle and the lower cranial portion of the greater trochanter of the femur
Prevents irritation and friction from large muscles
What is the CS of the trochanteric bursa?
Trochanteric bursitis that causes severe hindlimb lameness
What nerve appears once the gluteal medius muscle is removed?
Sciatic nerve
Sciatic nerve
Motor
Supplies the semimem, semiten, and biceps femoris
SC of the sciatic nerve?
Paralysis due to trauma or post-anesthesia recovery
Atrophy of muscles
Hip drop
Touch-toe lameness
Asymmetry
Hyperextension of stifle
Tibial and fibular nerves
Flex the hock
Femoral nerve
Extends the stifle
CS: hyperflexion, dropped stifle
Obturator nerve
Innervates the gracilis and adductor musckes
Sacroiliac ligament
Forms the attachment between the ilium of the pelvis and the vertebral column
CS of the sacroiliac ligament
Severe trauma (kick, fall) the lig will rupture causing Hunter’s Bump (sacro-iliac subluxation) –> one dropped hip
How is the hip joint articulation strengthened? (Preventing subluxation/ dysplasia)
- transverse lig of the acetabulum
- Lig of the head of the femur
- Accessory ligament originating from the prepubic tendon
How many compartments does the femoro-tibial joint have?
2, medial and lateral
How does the FTJ communicate with the FPJ?
Medial compartment of the FTJ communicates with the FPJ more than 80% in horses
Lateral compartment communicates with the FPJ in 25%
CS of the FPJ?
Joint arthroscopies/ injections and easier to puncture
Landmark: Either side of the patella lig
What is the landmark for the lateral compartment of the femoro-tibial joint?
Immediately behind the lateral patellar lig
How does the patella connect with the tibia and femur?
3 ligs and a fibrocartilage:
1. lateral patellary lig
2. Middle patellary lig
3. Medial patellary lig
4. Patellary fibrocartilage
Patellar locking mechanism
First component of the passive stay apparatus
Lateral patellary lig, medial patellary lig, and patellary fibrocartilage impt. because they guard the trochlea of the femur
Allows flexion and extension of the stifle (patella sliding on the trochlea)
Upward Fixation of the Patella
When patella stays on the femur (not sliding) and joint locks
Stifle and hock joint remain extended, can’t flex
How do you treat upward fixation of the patella?
Severing the medial patellary ligament
What muscles are on the lateral aspect of the tib?
Long digital extensor
Lateral digital extensor
Lateral digital flexor
Long digital extensor
Only muscle that reaches P3 and inserts on the extensor process of P3
CS pf the extensor process of P3
Pyramid disease
Joint injection in the coffin joint
CS of the tendon of the lateral digital extensor
Tendon joins the tendon of the long digital extensor on the dorsal (cranial) aspect of the third metatarsal bone
Stringhalt
Stringhalt
Involuntary flexion of the hock joint
From plant toxicity (flatweed/ false dandelion)
Bilateral sometimes
How do you treat stringhalt
Severing the tendon of the lateral digital extensor in 2 spots above the hock:
1. Musculotendinous junction
2. B4 the tendon joins the tendon of the long digital extensor
Reciprocal apparatus
Part 2 of PSA
Tendinous peroneus tertius forms the cranial part
Tendon of the superficial digital flexors forms the caudal part
What does reciprocal apparatus do for the leg?
Holds the leg standing for long time with minimum tension on the muscles, tendons and joints
Keeps a synchronized motion between the stifle and hock joints
If the stifle joint is flexed then the hock joint is __________
Flexed
What does rupture of peroneus tertius lead to?
Loss in synchronized action
Ex: stifle flexed while hock is extended
What are the two tendons of insertions for the peroneus tertius?
Superficial lateral branch
Dorsal branch
What are the two tendons of insertions for the tibialis cranialis?
Dorsal branch that inserts on the third tarsal bone
Medial branch (cunean tendon)
Cunean tendon
Medial tendon of insertion for the tibialis cranialis
Bursa under tendon
CS of the cunean tendon/ bursa
Cunean bursitis
Sever tendon for bone spavin
Bone Spavin
Osteoarthritis of tarsal bones 1,2,3 and central tarsal bone (seat of spavin)
Prevalence of bone spavin
67% in tarsometatarsal joints
8.3% in distal intertarsal joint
How do you treat bone spavin?
Cunean tenotomy to decrease stress on the joint in the dorsomedial pouch
How do you diagnose bone spavin?
Flexion test during lameness exam (spavin test)
Flexing hindlimb for 2 or 3 minutes before watching the horse trott/jog
Medial saphenous vein
Runs along the dorso-medial aspect of the hock joint
Must be avoided when injecting or performing arthroscopy in the hock joint
Calcanean bursa
SubQ bursa under the skin that covers the calcaneus
CS: calcification = capped hock
Communcation in the tarsal/ hock joint
Tarsocrual joint (largest) communicates with the proximal intertarsal joint
How id the tarsocrual joint accessed?
Through the dorso-medial pouch, avoiding the large medial saphenous vein
Bog spavin
Inflammation of the tarsocrural joint
Accumulation of fluid in the joint
Thoroughpin
Inflammation of the tarsal sheath of the deep digital extensor over the tuber calcaneus
Long plantar ligament
Distributes stress form the hock to the third metatarsal bone during extreme extension of the stifle and hock
CS of the long plantar lig
Excessive pulling causes curb/ thickening of the long plantar lig
Causes lig to push away the straight superficial digital flexor tendon (making it curved)
