What does the suspensory ligament do?

What is another name for the suspensory ligament?

- Maintains the position of the fetlock while standing

  (Part of the 'stay' apparatus)

- Stretches to accommodate the sinking fetlock, then uses  the stored energy to help pull the pastern upright.

- helps support the fetlock during the loading phase of the stride.

- The middle interosseus muscle

Where does the suspensory ligament originate?

Front Leg/Rear Leg

Front Leg

- Distal row of carpal bones

Rear Leg

- Distal row of tarsal bones

Where does the suspensory ligament bifurcate?

Where does the suspensory ligament insert?

(4 places)

- The suspensory ligament bifurcates above the fetlock into lateral and medial branches.

- Lateral and medial branches insert into the proximal sesamoids on their lateral and medial aspects.

- Lateral and Medial branches then insert into the main (common) extensor tendon in the proximal cranial area of P1

- It allows the fetlock to sink in a controlled manner by the muscle head slowly relaxing

- Pulls on P3 to bring the foot onto the toe

What is the 'route' of the DDFT? (Front/Rear Leg)

Where does the DDFT insert?

- On the front leg, the DDFT runs along the palmar aspect of the of the radius and cannon bones, between the sesamoid bones, on the cranial side of the Superficial Flexor Tendon.

- On the rear leg, the DDFT runs along the plantar aspect of the of the tibia and cannon bones, between the sesamoid bones, on the cranial side of the Superficial Flexor Tendon.

- On both front and rear legs, The DDFT inserts on the distal aspect of P3 at the semilunar crest.

What does the Subcarpal (Inferior/Distal) Check ligament (SCL) do?

Which leg is this ligament found on?

- It prevents the DDFT from overflexing when the muscle head becomes fatigued.

- Only on the front legs.

Where does the SCL originate?

Where does it insert?

- It originates at the proximal palmar cannon bone.

- It inserts into the DDFT about 1/3 of the way down the cannon bone.

- Assists the DDFT in allowing the fetlock to sink in a controlled manner.

- Allows the muscle head to contract and pull on P1 and P2, bringing them up and preparing for the anterior phase of the stride.

Where does the SFT bifurcate?

Where does the SFT insert?

- The SFT bifurcates below the fetlock.

- It inserts on the distal end of P1 and the proximal end of P2, laterally and medially.

What is the route of the SFT on the front leg?

- The SFT courses down the palmar radius, over the palmar carpus, between the 2nd and 4th metacarpals (splint bones) down the palmar cannon bone to palmar P1 and P2.

- It allows the fetlock to sink in a controlled manner by the muscle head slowly relaxing

- Pulls on P3 to bring the foot onto the toe

Where does the hind DDFT terminate?

What route does the DDFT take down the leg?

Where is it located in relation to the SFT?

- On the distal portion of P3 at the semi lunar crest.

- It runs down the plantar aspect of the tibia and cannon bones, between the sesamoid bones, down the plantar aspect of P1 and P2.

- It is located in front of the cranial aspect of the SFT.

- Assists the DDFT in allowing the fetlock to sink in a controlled manner.

- Allows the muscle head to contract and pull on P1 and P2, bringing them up and preparing for the anterior phase of the stride.

Does the SFT of the hind leg have a check ligament?

No

Where does the SFT of the hind leg attach before it inserts?

What purpose does this serve?

- It attaches at the point of the hock.

- The SFT of the hind leg is all tendon from the point of the hock to the insert points on the distal limb. As there is no muscle to fatigue, a check ligament is not necessary.

Where does the SFT of the hind leg originate?

Where does the SFT of the hind leg bifurcate?

Where does the SFT of the hind leg insert?

- It bifurcates below the fetlock

- Inserts at the distal end of P1 L/M and

- Inserts at the proximal end of P2 L/M

It extends the lower limb

- At the proximal end of P1, P2 and P3.

- The proximal end of P3 is also called the Extensor process.

It inserts at the proximal end of P1, P2 and P3. 

The P3 insertion is also known as the extensor process.

- What is the function of the suspensory (proximal) ligaments of the navicular bone?

- What additional function do these ligaments contribute to?

- They support the proximal medial and lateral ends of the navicular bone.

- They are an important part of the 'stay' apparatus that allows the horse to "sleep" while standing, with very little muscular effort.

- Where do the suspensory ligaments of the navicular bone insert?

- What is another term for these ligaments?

- They insert at the proximal edge of the navicular bone.

- The lateral and medial collateral sesamoidian ligaments.

Where does the distal navicular ligament originate?

Where does the distal navicular ligament insert?

- It originates at the dorsal aspect of the navicular bone.

- It inserts at the palmar/plantar proximal side of the semi-lunar crest of P3.

Does the rear leg have a suspensory ligament/interosseus muscle?

What is its route?

Yes

It originates at the distal tarsus/proximal palmar cannon bone, between the splint bones, and bifurcates above the fetlock. From that point, it has the same attach points as the front limbs.

Because these ligaments do not bear weight, so they are not prone to being over flexed.

- Patellar locking

- the reciprocal mechanism

- check apparatus

- Patellar locking

- the reciprocal mechanism

- check apparatus

What does the patellar locking mechanism do?

- The patellar locking mechanism allows the horse to immobilize the stifle/hock joint and rest with very little muscular effort.

How does the horse "lock" the patella?

- The horse locks the patella by resting weight on one hindlimb. This allows the stifle to extend past a certain point, and the patella will shift to the top of the trochlear groove and the patellar ligaments will 'lock' it in place, preventing further movement of the stifle.

How does it "unlock" the patella?

To unlock the patella, the horse shifts its weight to its other leg. The contraction of the quadriceps muscle draws the patella proximally. It the twists laterally and returns to the trochlear groove .