Picked-up nail – Causes

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

The anatomical structure of the sole and frog favours the entry of long, sharp foreign bodies into the collateral sulci of the frog, where they tend to become lodged. Short, sharp foreign bodies can penetrate at any point on the underside of the hoof. Although on first inspection picked-up nails cause only small lesions in the horn, these are often unexpectedly deep and injure vital structures.

Matthias Haab, Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Structures which may be affected by a nail pucture wound in the sole of the hoof

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Affected structures

Apart from the hoof capsule and the dermis, an injury from a picked-up nail can affect the following structures alone or in combination:

• Pedal bone

• Deep flexor tendon (DFT)

• Distal sesamoidean (impar) ligament connecting the navicular and pedal bones, possibly also with involvement of the coffin joint

• Navicular bursa, possibly also with involvement of the navicular bone• Digital flexor tendon sheath (DFTS)

• Digital cushion

• Lateral cartilage of the hoof (not shown)

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Departement für Pferde, Vetsuisse-Fakultät Universität Zürich

Typical streched 'tetanic' stance of a donkey with tetanus

Once the foreign body is removed, the entry hole generally closes up quickly and becomes virtually airtight, due to the elasticity of the horn. Since neither blood nor discharge can drain from the tightly closed wound, the risk of wound infection caused by a foreign body is particularly high. The lack of oxygen means that infections caused by anaerobic microbes, e.g. tetanus bacteria (Clostridium tetani), are the most feared complications.