The Equine Forelimb. The Shoulder and the Elbow Joints. Flashcards
What are the 6 major joints found in the equine forelimb?
Shoulder joint.
Elbow joint.
Carpal joint.
Metacarpophalangeal joint.
Proximal interphalangeal joint.
Distal interphalangeal joint.
What is the major function of the forelimb of the horse?
To bear weight.
How is the horses weight distributed between the forelimb and hindlimb?
55-60% is placed on the forelimb.
45-40% is placed on the hindlimb.
What is the function of the equine forelimb when the horse is moving?
At high speeds the forelimb will act as a shock absorber.
What area of the equine forelimb is most likely to suffer from lameness?
The area below the carpus.
The forelimb of the horse has what alignment?
It is straight.
What is another name for the shoulder joint?
The scapulo-humeral joint.
What type of joint is the shoulder joint?
A ball and socket joint.
Is the shoulder a stable joint?
Yes, it is very stable.
What 2 bones are involved in the shoulder joint?
The scapula.
The humerus.
The humerus fits into what part of the scapula to form the shoulder joint?
The glenoid cavity.
What part of the scapula is found in most species, but is missing in the horse?
The acromion process.
What animals lack an acromion process on their scapula?
The horse.
The pig.
What part of the deltoideus muscle is missing in the horse?
The acromion portion.
What is the structure of the joint capsule of the shoulder joint?
It is very thin.
Are there any collateral ligaments associated with the shoulder?
No.
What is the name of the bursa that is associated with the shoulder?
The bicipital bursa.
Why must we treat inflammation of the bicipital bursa separately from the shoulder joint?
As the bursa is separate from the shoulder joint.
What muscle of the shoulder is on the medial aspect of the shoulder?
The subscapularis muscle.
What muscles of the shoulder are on the lateral aspect of the shoulder?
The suprasinatus muscle.
The infraspinatus muscle.
The teres major muscle.
What is the origin of the tendon of the biceps brachii muscle?
The glenoid tubercle.
How does the tendon of the biceps brachii affect the shoulder joint?
It helps to stabilise the shoulder joint.
Where is the bicipital bursa of the shoulder located?
Between the tendon of origin of the biceps brachii and the joint capsule.
What are the main stabilisers of the shoulder joint?
The muscles that surround the joint.
The tendon of the biceps brachii.
What movements are performed by the shoulder joint?
Mostly flexion and extension.
Some abduction, adduction and rotation is possible.
What is the normal angle that the shoulder joint is flexed at?
115 degrees.
How does the angle of flexion help the horse?
It acts as an anti concussion mechanism.
What is transmitted up the leg when the horses hoof strikes the ground?
A concussive force is transmitted up the leg to the shoulder.
What is the major cause of lameness in equine forelimb?
The concussive force that is transmitted up the limb when the leg strikes the ground.
What is the anti-concussion mechanism of the shoulder?
The partial flexion of the shoulder helps to reduce the amount of concussion that passes through the limb.
What keeps the shoulder joint partially flexed at 115 degrees?
The tendons of the biceps brachii.
What are 4 important landmarks of the equine shoulder region?
The deltoid tuberosity.
The greater tubercle.
The spinous tuberosity.
The supraglenoid tubercle.
In the horse, what are the divisions of the greater and lesser tubercles of the humerus?
The cranial and caudal divisions.
What forms the point of the shoulder in the horse?
The cranial division of the greater tubercle.
What is the spinous tuberosity of the equine shoulder?
It is a prominence on the spine of the scapula.
Where is the transverse humeral retinaculum of the equine shoulder found?
It runs between the greater and lesser tubercle of the humerus.
What is the function of the transverse humeral retinaculum?
It holds the tendon of the biceps brachii in place.
How can the infraspinatus muscle cause lameness?
The bursa that protects the tendon of this muscle can become inflamed.
What is the function of the supraglenoid tubercle of the scapula?
It is the origin for the tendon of the biceps brachii muscle.
It is one of the major anchors for the stay apparatus.
Where is the deltoid tuberosity found on the horse?
On the lateral aspect of the shaft of the humerus.
What is the function of the intertubercular bursa of the shoulder joint?
It protects the tendon of the biceps brachii.
Does the intertubercular bursa communicate with the joint cavity of the shoulder?
No.
What is the best way to inject the shoulder joint?
By palpating the greater tubercle (point of shoulder).
Find the groove between the cranial and caudal divisions of the greater tubercle.
Place the needle here to inject fluids.
What type of joint is the elbow joint?
A compound synovial hinge joint.
What bones are involved in the elbow joint?
The condyles of the humerus.
The trochlea notch of the ulna.
The head of the radius.
What parts of the elbow joint does the capsule of the elbow attach to?
To the humerus, the radius and the ulna.
Where does the caudal aspect of the joint capsule of the elbow insert onto?
The proximal border of the olecrannon fossa.
Are there collateral ligaments associated with the elbow joint?
Yes.
Medial and collateral ligaments.
Where do the medial and lateral collateral ligaments of the elbow run between?
The condyles of the humerus to the radius and ulna.
What is the major difference between the medial and lateral collateral ligaments of the elbow?
The lateral collateral ligament is unbranched.
The medial collateral ligament has 2 divisions.
What are the 2 divisions of the medial collateral ligament of the elbow?
The cranial portion is the long portion.
The caudal portion is the short portion.
Where does the long division of the medial collateral ligament insert onto?
It inserts onto the radius, distally to the interosseus space.
The cranial part of the medial collateral ligament is the remnant of what muscle in cattle and horses?
The pronator teres muscle.
Where does the short division of the medial collateral ligament insert onto?
Onto the medial tuberosity of the radius.
Why is pronation and supination of the forelimb impossible in the horse and the cow?
As the radius and ulna are fused.
Is the lateral collateral ligament of the elbow branched or un branched?
It is unbranched.
Only the medial collateral ligament is branched.
Where does the lateral collateral ligament of the elbow run from and to?
Proximally attached to the lateral epicondyle of the humerus.
It inserts onto the radius.
In most species will the lateral collateral ligament of the elbow attach to the radius and ulna?
Yes, but the ulna part is absent in the horse.
Is the olecrannon ligament found in the horse?
No, it is only found in the cat and dog.
Which of the collateral ligaments of the elbow is part of the stay apparatus of the horse?
The lateral collateral ligament.
What is another name for the elbow joint?
The cubital joint.
What are the main movements of the elbow joint?
Flexion and extension.
Is arthrocentesis of the elbow performed on the medial or lateral side?
On the lateral side.
Why can we not perform athrocentesis of the elbow on the medial side?
As the pectoral muscles get in the way of accessing the medial collateral ligament.
How do we perform arthrocentesis of the elbow joint?
We palpate the lateral humeral condyle of the humerus and the lateral tuberosity of the radius.
We place the needle between these 2 regions, either cranially or caudally to the lateral collateral ligament.
