Endomysium

Endomysium is the word used to refer to the fine sheath of connective tissue layer of reticular fibers that surrounds (covers) each single muscle fibre. This layer includes includes blood vessels (capillaries), nerves and lymphatics. It is located around, i.e. outside of, the cell membrane of the muscle cell ("muscle cell' = "muscle fibre" = "muscle fibre"), that cell membrane also being known as the sarcolemma - see the list of layers of muscle tissue below.

Above: Cross-section of a fasicle, showing the endomysium surrounding each muscle fibre. (The single muscle fibre cut-away shows the sarcolemma below, i.e. within, the endomysium.)

Above: Cross-section of a fasicle, showing the endomysium surrounding each muscle fibre. (The single muscle fibre cut-away shows the sarcolemma below the endomysium.)

Endomysium should not be confused with other layers of connective tissue located in the structure of muscles.

Overall, the layers of muscle tissue are:

• Sarcolemma is the cell membrane that encloses each muscle cell (which is also known as a muscle fibre).
• Endomysium is connective tissue that wraps each individual muscle fibre.
• Perimysium is connective tissue that wraps bundles of muscle fibres - the "bundles" being known as fasicles.
• Epimysium is connective tissue that wraps the whole muscle.
• Fascia (or "deep fascia") is a layer of thickened connective tissue that covers the entire muscle and is located over the layer of epimysium.