Equine Conformation - Conformation of The Front and Hind Legs

Conformation of The Front and Hind Legs

The Cannon and Tendons

Long Cannon Bone

• The cannon is long between the knee and fetlock, making the knees appear high relative to the overall balance of the horse
• Reduces the muscular pull of the tendons on the lower leg.
• Uneven terrain or unlevel foot balance will magnify the stress on the carpus since lengthy tendons are not as stabilizing to the lower limb as shorter ones
• Increases the weight on the end of the limb, contributing to less efficient and less stable movement. Added weight to front legs increases the muscular effort needed in picking up a limb, leading to hastened fatigue.
• Increase in tendon/ligament injury, especially when the horse is also tied-in above the knee.
• Horses with long cannons are best for flat racing short distances.

Short Cannon Bone

• Cannon is relatively short from fetlock to knee as compared to knee to elbow
• This conformation is desirable in any performance horse
• A short cannon bone improves the ease and power of the force generated by the muscles of a long forearm or gaskin. Enables an efficient pull of the tendons across the back of the knee or point of hock to move the limb forward and back.
• Also reduces the weight of the lower leg so less muscular effort is needed to move the limb, which contributes to speed, stamina, soundness, and jumping ability.

Rotated Cannon Bone

• The cannon rotates to the outside of the knee so it appears twisted in its axis relative to knee. May still be correct and straight in alignment of joint, but more often associated with appearance of carpus valgus.
• Places excess strain on the inside of the knee and lower joints of the leg, potentially leading to soundness issues, although this is not common.

Bench or Offset Knees/ Offset Cannons

• The cannons are set to the outside of the knee so an imaginary plumb line does not fall through middle.
• Causes excessive strain on the lateral surfaces of the joints from the knee down and on the outside portions of the hoof.
• There is an exaggerated amount of weight supported by the medial splint bone, leading to splints.
• The horse is most suited for non-speed activities like pleasure riding, driving, and equitation.

Tied-in Below the Knee

• The cannon, just below the knee, appears “cut out” with a decreased tendon diameter. Rather than parallel with cannon, tendons are narrower than the circumference measured just above the fetlock.
• Affects speed event (racing, polo) and concussion events (steeplechase, jumping, eventing, endurance).
• Limits the strength of the flexor tendons that are needed to absorb the concussion and diffusion of impact through the legs, making the horse more prone to tendon injuries, especially at the midpoint of the cannon or just above.
• The leverage of muscle pull is decreased as the tendons pull against the back of knee rather than a straight line down back of leg. This reduces power and speed.
• Associated with a reduced size in the accessory carpal bone on back of knee over which the tendons pass. The small joints are prone to injury and don’t provide adequate support for the column of leg while under weight-bearing stress.
• Horse is most suited for sports that shift the animal's weight to the rear or that don’t depend on perfect forelimb conformation (dressage, driving, cutting).