Equine Thoracic Limb Flashcards
What part of the equine scapula is in the spine and not found in the dog?
scapular tuber
What structure of the scapula is found in dogs but not horses?
acromion
What is the bone classification of the scapula?
flat bone
The dog has one area of facies serrata on scapula, how amny does a horse have?
two
What is the bone classification of the humerus?
long bone (2 epiphysis and 1 diaphysis)
What thoracic limb bones are fused in the horse, but not in the dog?
radius and ulna
Since the radius and ulna are fused, which bone joins with the carpus?
only radius
Which equine carpal bones will always be visible?
II, III, and IV
Carpal bones I and V cannot always be seen due to their tiny size. Which sides can these bones be found if you are going to see them?
medial for carpal bone I
lateral for carpal bone V
Carpal bones of the horse are divided into how many rows?
two (proximal and distal)
What is the singular weight bearing digit in the horse?
digit III
The distal sesamoid bone is also known as?
navicular bone
Which joint is described by the following characteristics:
- simple, spheroid
- flexion and extension movements
- glenohumeral ligaments (capsular)
- thick biceps brachii origin tendion and bursa
humeral joint (shoulder)
Which ligaments of the equine humeral joint act like collateral ligaments but are capsular?
glenohumeral ligaments
How many carpal joints are there? List them.
Four
- antebrachiocarpia (radiocarpal)
- intercarpeae (intercarpal)
- mediocarpea (midcarpal)
- carpometacarpeae (carpometacarpal)
Which carpal joints are hinge?
- antebrachiocarpia (radiocarpal)
- mediocarpea (midcarpal)
What carpal joints are plane?
- intercarpeae (intercarpal)
- carpometacarpeae (carpometacarpal)
The sinovial capsule of the _____ joint is independent; the ____ and ____ is shared.
- radiocarpal
- inter, mediocarpea
How many digit joints are there? List them.
Three
- metacarpophalangeal (fetlock)
- proximal interphalangeal
- distal interphalangeal (coffin)
Which digit joint is a compound hinge joint with a small dorsal recess and large palmar recess?
Metacarpophalangeal joint (fetlock)
What are the palmar recess boundaries of the metacarpophalangeal joint (fetlock)?
proximal: ???
dorsal: metacarpal bone III
palmar: interosseous ligament
distal: proximal sesamoid bones
What are the extrinsic muscles of the equine shoulder?
- trapezius
- omotransversarius
- brachiocephalicus
- serratus ventralis
- pectoralis
- rhomboideus
- subclavius
What two extrinsic muscles of the equine shoulder are very attached and can be difficult to differentiate?
omotransversarius and brachiocephalicus
What is the “thoracic sling”?
the extrinsic muscles suspend the trunk between the forelimbs and fix the scapula (this is called synsarcosis)
What are the intrinsic muscles of the equine shoulder?
- supraspinatus
- infraspinatus
- deltoideus
- teres minor
- subscapularis
- teres major
- coracobrachialis
What is the OIA for supraspinatus m?
O: supraspinous fossa
I: greater and lesser tubercles of humerus
A: extend and stabilize the humeral joint
What is the OIA for infraspinatus m?
O: infraspinous fossa
I: superficial tendon – on the greater tubercle of the humerus (infraspinatus bursa)
I: deep tendon – on the caudal eminence of greater tubercle
A: fixator and abductor of the humeral joint
What is the OIA for deltoideus m?
O: caudal border of scapula, aponeurosis which covers infraspinatus
I: deltoid tuberosity
A: flexor and abductor of the shoulder
What is the OIA for subclavius m?
O: cranial part of the sternum closely associated to the supraspinatus m
I: supraspinatus muscle epimysium
A: complement the pectoral muscle
What is the OIA for subscapularis m?
O: subscapular fossa
I: lesser tubercle of humerus
A: stabilize the shoulder and adduction
What is the OIA for teres major m?
O: caudal angle of the scapula and adjacent caudal border of scapula
I: teres major tuberosity of humerus
A: mainly flexor of the shoulder
What are the intrinsic muscles of the brachium?
- triceps brachii
- tensor fasciae antebrachii
- anconeus
- biceps brachii
- brachialis
- coracobrachialis
What is the OIA for biceps brachii m?
O: supraglenoid tubercle
I: radial tuberosity, extensor carpi radialis via lacertus fibrosus
A: flexor of the elbow and extensor of the shoulder
What is located between the tendon of origin of biceps brachii and the intertubercular grooves of the humerus?
intertubercular bursa
What is the tendinous insertion of biceps brachii on the extensor carpi radialis m and is part of the stay apparatus?
lacertus fibrosus
What is the OIA for triceps brachii m?
O: long head – caudal border of the scapula
O: lateral head – deltoid tuberosity
O: medial head – medial aspect of humerus
I: olecranon tuber
A: extension of the elbow and flexion of the shoulder
Why do horses not have a pronator or supinator muscles?
Because the radius and ulna are fused
The intrinsic muscles of the antebrachium and manus are split into two groups: craniolateral and caudomedial. What are the muscles in the craniolateral group?
- extensor carpi radialis
- common digital extensor
- lateral digital extensor
- extensor carpi ulnaris (ulnarus lateralis)
The intrinsic muscles of the antebrachium and manus are split into two groups: craniolateral and caudomedial. What are the muscles in the caudomedial group?
- flexor carpi ulna’s (ulnar and humeral heads)
- flexor capi radialis
- superficial digital flexor
- deep digital flexor
What is the OINA for extensor carpi radialis m?
O: lateral supracondylar crest of the humerus
I: metacarpal tuberosity
N: radial nerve
A: extend and fix the carpus and flex the elbow joint
What is the OINA for common digital extensor m?
O: lateral epicondyle of the humerus
I: extensor process of distal phalanx and dorsal surface of proximal and middle phalanges
N: radial nerve
A: extend the carpus and digit and flex the elbow joint
What is the OINA for lateral digital extensor m?
O: lateral tuberosity of the radius, lateral collateral ligament of the elbow
I: dorsal aspect of proximal phalanx
N: radial nerve
A: extend the carpus and digit
What is the OINA for extensor carpi ulnaris (ulnaris lateralis) m?
O: lateral epicondyle of the humerus
I: short tendon – accessory carpal bone
I: long tendon – metacarpal bone IV
N: radial nerve
A: flex and abduct the carpus
What is the OINA for flexor carpi ulnaris m?
O: humeral head – medial epicondyle of the humerus
O: ulnar head – olecranon
I: accessory carpal bone
N: ulnar nerve
A: flex the carpus and extend the elbow joint
What is the OINA for flexor carpi radialis m?
O: medial epicondyle of the humerus
I: metacarpal bone II
N: median nerve
A: flex the carpus and extend the elbow joint
What is the OINA for superficial digital flexor m?
O: medial epicondyle of the humerus and radius (proximal accessory ligament)
I: flexor surfaces of proximal and middle phalanges
N: ulnar nerve
A: flex the digit (proximal interphalangeal joint) and carpus and extend the elbow joint
What is the OINA for deep digital flexor m?
O: humeral head – medial epicondyle of the humerus (distal accessory ligament)
O: ulnar head – olecranon
O: radial head – radius
I: flexor surface of the distal phalanx
N: median and ulnar nerves
A: flex the digit and carpus and extend the elbow joint
What is the continuation of suspensory ligament distal to sesamoids?
distal seamoidean ligaments
The suspensory apparatus is broken down into what four anatomical areas?
- proximal
- mid-body
- branches
- extensor branches
The suspensory ligament is also known as what?
interosseous muscle
The following characteristics describe what apparatus/ligament:
- very little muscle fiber in large animals
- connects bone to bone = ligament
- passive: DOES NOT FLEX JOINTS
suspensory apparatus / suspensory ligament
Can horses sleep standing?
NO
The following characteristis describe what apparatus:
- group of muscle, tendons, ligaments, fascia, and joints
- allows horses to maintain their standing posture for hours, without energy loss
- joints “blocks” and avoid energy losses
equine stay apparatus
