Iron Horse
Intramuscular Injection Sites

Most people select the neck area to administer intramuscular injections due to convenience and safety (i.e. unlikely to get kicked). However, the muscles in the neck may not have as much bloodflow (i.e. may not be as well-perfused) when compared to some of the other muscles in the body. Furthermore, adverse reactions (i.e. swelling and/or abscessation) that sometimes occur pursuant to intramuscular injections can result in severe neck stiffness and in some cases neurologic signs (due to the close proximity of the cervical vertebral column/ spinal cord to the neck musculature). For this reason, The Atlanta Equine Clinic generally recommends that you select another muscle to administer medications that are 2cc or greater in volume.

Since the biggest concern is for the safety of the person administering the
medication(s), a second person should always be present to handle the
horse's head. The handler should always remain on the SAME SIDE of the
horse as the person administering the medication.

We recommend using the muscles in the following order of preference:

  1. HAMSTRING muscles. ADVANTAGES: Muscles are well-perfused. No joints or major vessels/ nerves in the area. Great site for drainage in the event that abscessation occurs. DISADVANTAGES: This area places the administrator in a precarious position so may be relatively dangerous in sensitive horses.

  2. GLUTEAL muscles. ADVANTAGES: Muscles are well-perfused. No joints or major vessels/ nerves in the area. Relatively safe for the administrator. DISADVANTAGES: Not a great site for drainage in the event that abscessation occurs.

  3. PECTORAL muscles. ADVANTAGES: Muscles are well-perfused. No joints or major vessels/ nerves in the area. Relatively safe for the administrator. Easy to administer. Great site for drainage in the event that abscessation occurs. DISADVANTAGES: Some horses do not like getting injected in this area. The muscles are relatively small and may become sore rather quickly with multiple (serial) treatments.

  4. TRICEPS muscles. ADVANTAGES: Muscles are well-perfused. Relatively safe for the administrator. Easy to administer. Great site for drainage in the event that abscessation occurs. DISADVANTAGES: Many horses do not like getting injected in this area. The muscles are relatively small and may become sore rather quickly with multiple (serial) treatments.

  5. CERVICAL (neck) muscles. ADVANTAGES: Very safe for the administrator. Easy to administer. DISADVANTAGES: Muscles not as well-perfused. Major bones and cervical spinal cord in relative proximity. Not a great site for drainage in the event that abscessation occurs. Scar tissue development in this area (that can occur pursuant to repeated injection) may result in decreased performance (particularly if neck flexibility is important). This method should only be used if horse will not tolerate injection anywhere else.

The Atlanta Equine Clinic - 2011
Back to Library