Ischemic deep myopathy of the pectoral muscle in poultry.

This lesions consist of a deep pectoral muscle myopathy or green muscle disease. It affects heavy breeds of poultry (turkeys or broilers with a lot of weight) in intensive production systems and is usually located in the supracoracoid muscles .

It is also known as Oregon’s disease because it was described for the first time in turkeys bred in Oregon. It may be unilateral or bilateral. It is an ischemic myopathy. The muscle is enveloped by a non-elastic fascia, so that when an intense muscular activity happens ( such as in strong wing flapping) the muscle increases in size due to the blood supply (up to a 20% increase of volume). The expansion is prevented by the fascia and consequently the muscle is constricted and the blood flow impaired, causing ischemia.

The lesion seen in the images would be the chronic stage. In the acute phase, the muscle is gelatinous, reddish and eventually becomes greenish.

Deep pectoral muscle of a broiler with a conspicuous greenish discolouration.

Deep pectoral muscle of a broiler with a conspicuous greenish discolouration.