Vascular perfusion of the dorsal and palmar condyles of the equine third metacarpal bone.

The research article studies the perfusion or blood flow in different parts of the third metacarpal bone in horse limbs. The research finds out that there is more blood flow in the dorsal(condyle on the back side) than the palmar(condyle on the front side) when the fetlock joint was in passive flexion(done by external force) and when in maximal extension(fully straightened), the blood flow is drastically reduced on the palmar side.

Study Objective and Methods

• The aim of this research was to study and compare the blood flow in the dorsal and palmar condyles of the third metacarpal bone (McIII) in horse limbs in both passively flexed and maximally extended fetlock joints using India ink perfusion.
• This was a descriptive cadaver study conducted on the forelimbs obtained from five thoroughbred horses that were euthanized for reasons not related to lameness.
• The limbs were perfused with India ink and then randomly assigned to passive flexion or maximal extension of the fetlock joint. The limbs were then sectioned sagittally in 3 mm sections through the fetlock.
• A total of 12 sections per limb were processed using a modified tissue-clearing technique. These sections were then digitally imaged and the bone perfusion was evaluated using image analysis software.

Results and Conclusion

• The study found that 78% of the sectioned limbs in passive flexion and 92% of the maximally extended sections showed greater blood flow in the dorsal condyle than the palmar condyle.
• When the limbs were placed in maximal extension, the perfusion or blood flow to the palmar aspect of the condyle was significantly decreased (P < 0.0001) as compared to passive flexion.
• Therefore, the study concludes that the palmar condyle of McIII receives less blood flow than the dorsal condyle when the fetlock joint is in passive flexion. Furthermore, this difference in perfusion becomes more pronounced during maximal extension.
• The researchers suggest that the perfusion differences between the dorsal and palmar condyles of the third metacarpal bone may be responsible for the development of Palmar osteochondral disease lesions.