ID the major bones in each topographic region of the thoracic limb.
- Shoulder - scapula
- Brachium - humerus
- Antebrachium - radius & ulna
- Carpus - carpal bones
- Metacarpus - MC II, III, IV
- Digit - P I, II, III
Which skeletal structures are included in the manus?
Carpus + metacarpus + digits
What skeletal structures comprise the digit?
Pastern + coronet + hoof
Compare the spine of the scapula and scapular cartilage of the equine to the canine scapula.
Dogs do not have scapular cartilage, have a larger spine, and lack a tuber scapulae
What is the association of each epicondyle of the humerus with the muscles of the antebrachium?
- Lateral epicondyle - origin for extensors of the carpus and digit
- Medial epicondyle - origin for the flexors of the carpus and digit
Which tendons are found in the grooves on the distal end of the radius?
- Common digital extensor
- Extensor carpi radialis
- Extensor carpi obliquus
Which synovial compartments of the carpus intercommunicate?
Midcarpal joint compartment + carpometacarpal joint compartment
What is the carpal canal?
Space on the caudal palmar aspect that channels the flexor tendons into the metacarpus
Which structures form the boundaries of the carpal canal?
Palmar carpal ligament (deep) + flexor retinaculum (superficial)
Which major tendons pass through the carpal canal?
Deep digital flexor tendon + superficial digital flexor tendon
What is the name of the tendon synovial sheath that passes through the carpal canal?
Common synovial sheath
What are the anatomic and common names for the MC bones?
- MC II - medial splint bone
- MC III - cannon bone
- MC IV - lateral splint bone
Where are the proximal and distal sesamoid bones located?
- Proximal sesamoids - paired bones on the palmar surface of MC III (cannon bone)
- Distal sesamoid (navicular) - wedge-shaped bone on the palmar surface between the middle and distal phalanx
What are the major anatomic features of the distal phalanx?
PIII - coffin bone
Differentiate between phalanx and phalanges
Phalanx = singular, phalanges = plural
What are the chestnus/ergot and where are they?
- Chestnut - vestige of carpal pad on medial surface of antebrachium
- Ergot - vestige of metacarpal pad on back of fetlock
Which pectoral muscles are present in the horse?
- Desending pectoral
- Transverse pectoral
- Deep pectoral
Why is the canine abductor pollicis longus referred to as the extensor carpi obliquus in the horse?
Horses don't have a pollicis longus (only have one toe)
What is the lacertus fibrosus?
Blends with the deep fascia of the forearm and joins the tendon of the extensor carpi radialis
What are the anatomic terms for the proximal and distal check ligament?
- Proximal - superficial digital flexor ligament
- Distal - accessory ligament of the deep digital flexor
Where is the interosseus muscle located?
Arises from the distal row of carpal bones and proximal end of MCIII, passes distally, and is applied to the palmar surface of MCIII; divides into two branches proximal to the fetlock. Strong, flat, tendinous band
What is the common name for the interosseus muscle?
Where does the extensor branch of the interosseus muscle insert?
What is the relationship of the interosseus muscle with the proximal sesamoid bone?
Interosseus inserts on the proximal sesamoid
Describe the arrangement of the interosseus muscle and the flexor tendons on the caudal aspect of the metacarpus
Interosseus m. lies on MC III and IV and is deep to the DDF (which is deep to the SDF)
Which sesamoidean ligaments are present in the horse?
Oblique, straight, and cruciate sesamoidean ligaments
What is the function of the digital annular ligaments? How many are present?
Function to keep the tendons in place; there are 2 - distal digital annular ligament and proximal digital annular ligament
Which structures are present in the digital synovial sheath?