Equine/ruminant Thoracic Anatomy Flashcards
Anatomical terms for
Shoulder
Point of shoulder
Point of elbow
Knee
Cannon bone
Shoulder - region between dorsal margin of scapular cartilage & shoulder joint
Point of shoulder - cranial part of the greater tubercle of humerus
Point of elbow - olecranon
Knee - carpus & stifle joint
Cannon bone - metacarpal III
Anatomical terms for
Splint bones
Button of splint
Fetlock
Pastern
Long pastern bone
Short pastern bone
Pastern joint
Coronary band, cornet
Splint bones - metacarpal II (medial) and metacarpal IV (lateral) of the horse
Button of splint - distal extremity of metacarpal II or metacarpal IV of horse
Fetlock - metacarpophalangeal or metatarsophalangeal joint (ankle)
Pastern - region of the digit between fetlock & hoof
Long pastern bone - proximal phalanx, p1
Short pastern bone - middle phalanx, p2
Pastern joint - between p1 and p2
Coronary band, coronet - junction between skin and hoof
Anatomical terms for
Coffin bone
Coffin joint
Navicular bone
Chestnut
Ergot
Coffin bone - distal phalanx, PIII: (pedal bone)
Coffin joint- between PII and PIII
Navicular bone - distal sesamoid bone
Chestnut - horny growth on medial surface proximal to carpus
Ergot - small mass in the tuft of hair on palmar / plantar surface of fetlock
Horse vs cow
Subclavius muscle
Modified pectoral muscle
Large in horse, very small in cow
Horse vs cow deltoideus muscle
Aponeurotic part is large w no acromial part in horse
Horse vs cow - triceps muscle
Both species have 3 triceps head, no accessory had
Capped elbow or shoe boil
Subcutaneous bursa can become inflamed from weight or laying on it
Lacterus fibrosis
Extension of tendinous central bicipital tendon onto the extensor carpii radialis
Extensor capri radialis
Facia of ECR receives lacertus fibrosis & distributes it to the metacarpal tuberosity
Functional part of stay apparatus in equine forelimb
Extensor carpi obliquus
Called abductor digit I in the dog
Superficial digital flexor
Considered a check ligament, band originates from the radius & intersects w main tendon, near the level of the carpus
Deep digital flexor
Also a check ligament, distal or accessory check is much larger than the proximal.
Distal originates from the palmar capsule of carpus & intersects w main tendon - proximal 3rd of metacarpus
Deep digital flexor ( accessory)
Check ligament, helps prevent hyper-extension of fetlock joint by checking deep digital flexor tendon
Important arteries in distal limb
Median artery
- medial palmar artery
- lateral palmar artery
==medial palmar digital artery
==lateral Palmer digital artery
Lateral palmar Arteries
Run in a groove between digital flexors and suspensory ligament
Medial palmar artery
Run deep and inclines to midline (axially) and gains midline
Splits symmetrically just above the fetlock into digital arteries
Termination of digital arteries
Entering solar canal and anastomosing in the terminal arch
Nerves of thoracic limb
In horses and cows, the median and musculocutanous nerves run together
What pathogenesis occurs if suprascapular nerve is damaged?
Sweeney = atrophy of Supra and infra scapular muscles
Nerves distal to the carpus
Mainly median and ulnar - primarily sensory nerves (no muscles distal to carpus)
Ulnar nerve
Distal to carpus - sensory
Median nerve
Main supply to distal limb, divides into medial and lateral palmar nerves
Med/lat palmar metacarpal nerve
Both arise near carpus from a small branch of the lateral palmar nerve
Medial and lateral Palmer digital nerves
Continuation of the respective palmar nerves
Each have dorsal branches to fetlock & pastern region
Interosseous tendon in cow
The equivalent of the suspensory ligament of the horse. More muscular in composition in the calf
Weight distribution on hoof/claw
Medial claw bears majority in thoracic limb
Lateral claw bears majority of weight in hind limb (80%)
Carpus, metacarpus and digits in cow
6 carpal bones
2 weight bearing metacarpal bones (III and IV)
2 weight bearing digits
4 proximal and 2 distal sesamoid bones
Dewclaws
Not bones
Extensors in ruminant thoracic limb
Lateral digital extensor
Common digital extensor
Medial digital extensor
Importance of interdigital ligaments
Holds claws together
Bier block
Use of dorsal commo digital vein III for regional anesthesia in bovine
Modified interosseous muscle in horses
= suspensory ligament
Lies on palmar surface of MC III, between MC II and MC IV (splint bones)
Extensor branches in equine
Pass dorsally from each side, medial & lateral to attach to the extensor process of p3
Job of suspensory ligament
Helps prevent hyper extension of fetlock joint
Distal sesamoidean ligaments
Superficial, straight, I
Middle, oblique, V
Deep, cruciate, X
Ligaments of the digital sesamoid bone
suspensory ligament of the digital sesamoid bone
distal sesamoid impair ligament
Lateral collateral ligament of pastern joint
lateral collateral ligament of coffin joint
lateral collateral ligament of navicular bone
Position of palmar annular ligament of the fetlock
Abaxial side of one proximal sesamoid over the other
Location of digital annular ligaments
Proximal digital annular ligament X shaped
Distal annular ligament
Medial side of distal P1 around palmar surface to lateral side of P1
