Axillary Wounds in Horses: Why These “Small” Injuries Can Become Emergencies

By Dr Duncan Houston

Axillary wounds are one of the most misleading injuries in horses.

They sit in the crease between the foreleg and chest, often looking like a small cut or puncture. But this location behaves very differently from most other wounds. With every step, the movement of the limb can pull the wound open and draw air deep into the tissues.

That is where things escalate.

A wound that looks minor on the surface can track deep into the body wall, fill the tissues with air, and in more serious cases affect the chest and breathing. This is why axillary wounds are treated very differently from a typical skin laceration.

Quick Answer

Axillary wounds in horses should always be treated as urgent because they can draw air under the skin and into deeper structures. Even small wounds can lead to subcutaneous emphysema or, in severe cases, pneumothorax. Early veterinary treatment, proper wound management, and close monitoring are critical.

Quick Decision Guide

Small wound between the foreleg and chest → treat as urgent, even if it looks minor

Swelling that feels like bubble wrap under the skin → likely subcutaneous emphysema

Swelling spreading across chest, neck, or shoulder → ongoing air entry is occurring

Any change in breathing → emergency

Horse appears normal initially → still requires close monitoring for the next 2–4 days

What Is the Axillary Region?

The axillary region is the area where the horse’s foreleg meets the chest.

This area:

• moves constantly

• is difficult to bandage securely

• allows tissue planes to separate easily

• is exposed to sweat, friction, and contamination

Because of this movement, wounds here behave differently. Instead of simply opening and closing, they can act like a valve.

Air is pulled in with movement but cannot escape easily.

What This Usually Turns Out To Be

When a horse gets a wound in this area, the real situation is usually one of these:

• a deeper wound than it appears

• a wound that begins drawing air into the tissues

• a wound that worsens over the next few days rather than immediately

• a wound that needs sealing, not just cleaning

The mistake I see most often is assuming it is just a superficial cut.

In this location, that assumption can be dangerous.

Why These Wounds Are So Problematic

The issue is not just the wound itself.

It is the combination of:

• movement of the forelimb

• separation of tissue layers

• repeated air entry

• contamination

• delayed progression of complications

This means the wound can worsen after the initial injury, not just at the moment it occurs.

Subcutaneous Emphysema: The First Warning Sign

Subcutaneous emphysema occurs when air becomes trapped under the skin.

In horses with axillary wounds, this can spread widely across:

• the chest

• the shoulder

• the neck

• even further across the body

What It Feels Like

• crackling under the skin

• bubble-wrap sensation

• soft swelling that moves under pressure

Decision Checkpoint

If the swelling crackles, it is not fluid. It is air.

And that means the wound is still actively drawing air inward.

Why Pneumothorax Is the Major Risk

If air continues to track deeper, it can enter the chest cavity.

This leads to pneumothorax, where air prevents the lungs from expanding properly.

Signs to Watch For

• faster or shallow breathing

• increased effort to breathe

• reluctance to move

• anxiety or distress

• worsening swelling with breathing changes

This is a life-threatening situation.

What Vets Care About Most

When assessing an axillary wound, the key questions are:

• how deep is the wound

• is it acting like a one-way valve

• is air spreading under the skin

• is the chest involved

• can the wound be sealed effectively

• is the horse moving enough to worsen the problem

What matters most is stopping the air movement, not just cleaning the surface.

Why Cleaning Alone Is Not Enough

With most wounds, cleaning is the priority.

With axillary wounds, sealing is just as important.

If the wound continues to pull air inward, the problem will continue even if the surface looks clean.

This is why treatment often involves:

• deep packing

• partial closure

• creating a barrier to stop air entry

Without this, the wound can continue to worsen.

Treatment Principles

Treatment focuses on:

• exploring the true depth of the wound

• cleaning thoroughly

• preventing further air entry

• protecting from contamination

• restricting movement

• monitoring for respiratory changes

Bandaging may be difficult in this area, so alternative methods such as sutured bandages or packing are often used.

Movement Restriction Is Critical

Every step can draw more air into the wound.

This is why early management often includes:

• stall confinement

• limiting unnecessary movement

• controlled handling

Decision Checkpoint

If the horse is walking freely while the wound is still open, the condition may worsen.

Severity Framework

Common Mistakes Owners Make

• assuming the wound is minor

• focusing only on the surface

• missing early emphysema

• allowing too much movement

• waiting for breathing issues before acting

The biggest mistake is underestimating the wound.

What Should You Do Right Now?

If you find a wound in this area:

1. Treat it as urgent

2. Restrict movement immediately

3. Call your veterinarian

4. Check for swelling and crackling under the skin

5. Monitor breathing closely

6. Continue monitoring for several days

Simple checkpoint:

axillary wound + swelling = serious

axillary wound + breathing change = emergency

When Is This an Emergency?

It is urgent from the moment the wound is found.

It becomes critical if:

• swelling spreads rapidly

• breathing changes

• the horse becomes distressed

• the condition worsens over time

Do not wait for obvious signs.

Prevention

Prevention focuses on:

• safe fencing and stable design

• removing sharp objects

• checking for hazards in turnout areas

• monitoring horses after injuries

These wounds are often caused by avoidable environmental risks.

Frequently Asked Questions

Are axillary wounds always serious?
Not always, but they should always be treated as potentially serious.

What does subcutaneous emphysema feel like?
Like bubble wrap or crackling under the skin.

Can this affect breathing?
Yes. In severe cases, it can lead to pneumothorax.

Why is this area different?
Movement and tissue structure allow air to be drawn inward.

How quickly can it worsen?
Often within 2–4 days after the initial injury.

Final Thoughts

Axillary wounds are a perfect example of why location matters more than appearance.

A small wound in the wrong place can behave like a much larger injury. The key is recognizing the risk early, managing it properly, and not waiting for obvious complications before acting.

If you’re unsure whether a wound in this area is serious, how to manage swelling, or whether breathing changes are becoming dangerous, ASK A VET™ can help you assess the situation quickly and guide your next steps with clear, practical advice.