Lecture 6: Anatomy of Leg and Tarsus Flashcards
What two structures is the leg in between
Stifle and hock
How is movement of the leg achieved
Via muscles that move the stifle joint
What are the three tiers of hock and tarsus
Proximal, middle, and distal
What is in the proximal tier
Talus/astragalus (medial) and calcaneus (lateral)
What is in the middle tier
Central tarsal bone
What is in the distal tier
Tarsals 1-4 number medial-lateral
4th tarsal intrudes into middle tier
What is the equine variation in the distal tier
1+2 tarsals fuse
What is the bovine variation in the distal tier
2+3 tarsals fuse and central bone and 4 tarsal fuse
Describe the layout of the Carnivora hock and tarsus tiers
Tibia and fibula articulate with talus and calcaneous
Talus articulates with the central bone and calcaneous with the 4th tarsal
None of the tarsals are fused and they articulate with metatarsals
Describe the layout of the equine hock and tarsus tiers
Tibia and fibula articulate with talus and calcaneus
Talus articulates with the central bone and the calcaneus articulates with the 4th metatarsal
The 1st and 2nd metatarsal are fused
tarsals fuse with metatarsals (mainly 3)
Describe the layout of the bovine hock and tarsus tiers
The tibia and fibula articulate with talus and calcaneus.
The talus and calcaneus articulate with the fused central bone and 4th metatarsal which fuse to the metatarsals
Metatarsals 2 and 3 are fused
Trochlea of talus
Proximal surface, articulates with tibia and fibia
Head of talus
Distal articulate surface articulates with central tarsal
Sustentaculum tali
Supports plantar surface of talus (in between talus and calcaneus), supports tendon of flexor digitorium superficialis
Tuber calcanei
Proximal end of calcaneus, attachment for calcaneal tendon. Level for movement at hock
Head of calcaneus
Articulates with fourth tarsal
Base of metatarsals
Articulates with tarsals
Body of metatarsals
Middle of metatarsal
Head of metatarsal
Articulates with phalange
How is the proximal trochlea surface of talus in the dog shaped
Shaped to fit tibia and fibula
How is the head of talus in dog shaped
Articulates with central bone and is rounded to permit mid foot rotation- for grasping things
How is the trochlea of talus in the horse shaped
Conforms with cochlea of tibia providing extension and flexion at talo-crural joint
Describe the Talar head in the horse
Very small and flattened providing greater stability at talar-central articulation
What is the function of the obliquity of joint surfaces at talo-crural joint in horse
Causes distal limb to be carried laterally when flexion occurs at hock
In most mammals what does the talar head articulate with
Central bone
What happens to talar head in artiodactyl’s
Talar head expands to articulate with central and 4th tarsal
What are the 4 levels of articulation at the hock
Tarso-crural joint
Proximal intertarsal joint
Distal intertarsal joint
Tarsometatarsal joint
In most species where does almost all movement occur in the hock
Talocrural joint
What are the main ligaments of the hock
Medial and lateral collateral ligaments and the long plantar ligaments
What are the medial and lateral collateral ligaments
Extend from the tibia and tibia to base of metatarsus. Each have a long superficial part that ends full length of ligament and then a short deeper part that is restricted to proximal level of articulation
What is the long plantar ligament
Extends from plantar surface of calcaneus over 4th tarsal bone to metatarsus
What is the role of the smaller ligaments in the hock
Hold tarsal bones together and maintain integrity of peas
What are the three synovial compartments of the hock
Tarsocrural and proximal intertarsal joints
Distal intertarsal joint
Tarsometatarsal joints
What are the 4 components of the tarsocrural and proximal intertarsal joints
- Lateraldorsal pouch
- Mediodorsal pouch
- Medial plantar pouch
- Lateral plantar pouch
Weaker parts of joint where swelling may occur due to over-distension
What muscles make up the caudal compartment of the leg
Gastrocnemius
Flexor digitorium superficialis
Flexor digitorium profundus (lateralis, medialis, and caudal is)
Popliteus
What artery supplies the caudal compartment of the leg
Saphenous
What nerve innervates the caudal compartment of the leg
Tibial
What is the main action of the caudal compartment of the leg
Extension of tarsus and flexion of digits
What two muscles make up the common calcaneal tendon
Superficial flexor and gastrocnemius
Politeus OINA
O: caudal aspect of the articular surface of the lateral condyles of the femur
I: medial border of the tibia and its proximal third
N: tibial
A: medial rotation of the tibia relative to the femur during flexion or swing phase locomotion
What are the muscles in the craniolateral compartment of the leg
Tibialis cranialis
Extensor digitorium Longus
Peroenus longus
Peroneus brevis
Peroneus tertius
What artery supplies the craniolateral compartment
Cranial tibial artery
What nerve innervates the craniolateral compartment
Fibular(peroneal)
What is the main function of the craniolateral compartment
Flexion of tarsus, extension of digits
Peroneus tertius OINA
O: extensor fossa with extensor digitorium longus
I: bifurcates at hock
- lateral branch: calcaneus and 4th tarsal
- dorsal branch- proximal part of 3rd tarsal and 3rd metatarsal
N: fibular nerve
A: connects the actions of the stifle and hock so they extend simultaneously
What two nerves innervate the leg and tarsus
Tibial and fibular nerves that branched off sciatic
Describe the pathway of the tibial nerve
Enters the leg between heads of gastrocnemius then gives off caudal aural branch as well as innervating caudal leg muscles. The nerve enters between the tarsus and common calcaneal tendon and caudal crural muscles then splits into medial and lateral plantar nerves that innervate the pes
Describe the pathway of the fibular nerve
Enters the leg lateral to gastrocnemius then gives of lateral sural cutaneous branch as well as innervating the craniolateral muscles. The nerve continues into the dorsum of the pes
Describe the blood supply of hindlimb for dog and cat
External iliac gives off femoral artery, the deep femoral artery and saphenous branch off femoral artery
The saphenous has a cranial and caudal branch
Cranial branch of saphenous gives off dorsal metatarsal artery and the caudal branch gives off medial and lateral plantar and metatarsal arteries
Further distally past the femoral artery is the popliteal artery which will give off the popliteal artery and dorsal pedal artery
Describe the main arteries of the horse hindlimb
External iliac to the femoral artery which gives off the deep femoral artery and the saphenous
The saphenous will for a loop and anastomose with the caudal tibial. The saphenous also gives off the medial and lateral plantar and metatarsal arteries as well as the medial and lateral digital arteries
Further distal of femur is the popliteal artery which gives off the caudal tibial artery which anastomose with saphenous. It also gives off the cranial tibial artery.
Where does Lateral saphenous vein drain
Popliteal vein
Where does medial saphenous vein drain
Femoral vein
