Lecture 14 - Leg and tarsus Flashcards
What are the bones of the “leg”?
Tibia and fibula
What are the bones of the hock?
tarsals and metatarsals
What are the muscles of the pes?
Metatarsals and phalanges
What are the joints of the hock?
Talocrural
What are the other joints of the leg/tarsus?
TMT, MTP, and IP
What do the muscles in the leg and tarsus region act on?
moving the tarsus and pes
What are two compartments in the leg?
Caudal and crainolateral
What artery supplies the caudal compartment?
Saphenous a.
What nerve supplies the caudal compartment?
Tibial n.
What are the main actions of the caudal compartment?
Extension of tarsus and flexion of digits
What artery supplies the crainolateral compartment?
Cranial tibial a.
What nerve supplies the crainolateral compartment?
Fibular n.
What are the main actions fo the crainolateral compartment?
Flexion of tarsus and extension of digits
What are the three tiers of the tarsal bones?
Proximal, middle, and distal
What is within the proximal tier of tarsal bones?
Talus/Astragalus (medial)
Calcaneus (lateral)
What is within the middle tier of tarsal bones?
Central tarsal bone
What is within the distal tier of the tarsal bones?
Tarsals 1-4 (mediolateral)
What is different about the fourth tarsal bone?
constantly present, much deeper, and intrudes into the middle tier
What is different about the tarsal bones in equidae?
1+2 fuse
What is different about the tarsal bones in bovidae?
2+3 fuse and central+4 fuse
What part of the talus articulates with the tibia?
Proximal trochlear surface
What does the distal surface of the talus articulate with?
Central bone
What does the distal surface of the talus look like in horses?
Flattened
What does the flattened talar head in horses provide?
Greater stability at the talar/central articulation
What occurs at the talo-crural joint?
Trochlea of talus conforms with cochlea of tibia providing free excursion
What happens at the talo-crural joint when the there is flexion at the hock in horses?
Distal limb is carried laterally due to the shaping of the talo-crural joint
What does the talar head in artiodactyls articulate with?
Central and fourth tarsal
What is different about the shape of the talar head in artiodactyls?
Expanded
Forms double-pulley astragalus
What are the parts to the calcaneus?
Sustentaculum, tuber calcanei, and head
What does the calcaneus support?
Plantar surface of talus and tendon of flexor digitorum superficialis
What surface is at the proximal end of the bone?
Tuber calcanei
What attaches at the Tuber Calcanei?
Calcaneal tendon
What does the tuber calcanei provide?
Free lever arm for movement at the hock
What does the distal end articulate with?
Fourth tarsal
What is MT1 in dogs?
dewclaw, not all dogs have it
What are the four levels of articulation?
Tarso-crural joint
Proximal intertarsal joint
Distal intertarsal joint
Tarsometatarsal joint
What joint does most movement occur?
Crurotarsal joint
What type of joint is crurotarsal (movement-wise)?
Atypical hinge joint
What happens with foot when carried forward with flexion?
Lateral deviation
How does the crurotarsal joint help the pelvic limb?
Helps it be external to thoracic limb when they overlap during high speed running
What joint is there some movement in ruminants and carnivores?
Talocentral joint - limited flexion
Why is movement allowed at this joint in ruminants/carnivores?
Curved surfaces of the joint
Where are the three synovial compartments?
1) Tarsocrural and proximal intertarsal joint
2) Distal intertarsal joint
3) Tarsometatarsal joint
Where are there pouches located?
Tarsocrural and proximal intertarsal joints
What are the four pouches?
Laterodorsal, mediodorsal, medioplantar, and lateral plantar
What is the significance of the pouches?
Weaker part of the joints, swelling can occur here due to overdistension
What are the two main ligament groups in the hock?
Collateral ligaments (medial/lateral) Long plantar ligament
Where are the collateral ligaments coming from and going to?
Extend from tibia/fibula to base of metatarsus
What are the two parts each collateral ligament consists of?
Long superficial and shorter deep
Where is the short, deep ligament restricted to?
Proximal level of articulation
Where is the long plantar ligament?
Caudal
Where does the long plantar lig. start and end?
Extends from plantar surface of calcaneus over 4th tarsal bone to the metatarsus
What do the smaller ligaments do?
Hold tarsal bones together and maintain the integrity of pes
What is different about the tibialis cranialis in ungulates?
Passes between split in fibularis tertius and spilts into dorsal and medial branch
Where does the dorsal branch of the tibialis cranialis go?
Metatarsal tuberosity
Where does the medial branch of the tibialis cranialis go?
1st and 2nd tarsal bones
What is different about fibularis longus and brevis in horses?
not present
What muscle is missing in carnivorans?
Fibularis tertius
What muscles contribute to the deep digital flexors?
flexor digitorium, flexor digitorium medialis, and tibialis caudailis
In horses and ruminants the tibialis caudalis tendon merges with what?
FDL and FDM
What is the important muscle in pes?
Interossei
What differs about the extensor brevis in the pes from the manus?
Muscle belly originates on dorsum of talus and calcaneus and inserts dorsally on digits III-V
What is the origin of the common fibular n?
Sciatic nerve
What nerves branch off the common fibular n.?
Superficial fibular n. and Deep fibular n.
What does the Tibal n. originate from?
Sciatic nerve
What muscles does the common fibular n. innervate?
Crainolateral leg group
What is the path of the common fibular n.?
Passes lateral to lateral gastronemius to enter leg laterally
What cutaneous branch comes off the common fibular n.?
Lateral sural cutaneous branch
Where does the common fibular n. branch?
Near fibular head
What does the deep fibular n. innervate?
Muscles of the crus
What cutaneous innervations does the deep fibular n. provide?
Dorsal pes
What muscle group does the tibial n. innervate?
Caudal leg group
What is the path of the tibial n.?
Passes between the two heads of the gastronemius to enter the leg
What cutaneous branch comes off the tibial nerve?
Caudal sural cutaneous branch
What does the tibial n. spilt into?
Medial and lateral plantar nerves
Where does the tibial n. split?
When it enters the hock
Where does the tibial n. provide sensation?
dorsal pes
What are the two superficial veins in the leg?
Lateral and medial saphenous v.
What does the lateral saphenous v. drain into?
Popliteal v.
What does the medial saphenous v. drain into?
Femoral v.
