Muscle Anatomy

Lesson 1, Topic 1
In Progress

Muscle Anatomy

suze April 7, 2019

The anatomy of muscles includes both gross anatomies, comprising all the muscles of an organism, and, on the other hand, microanatomy, which comprises the structures of a single muscle.

Microanatomy of Muscles

Muscles are a soft tissue made up mostly of water and proteins. They have a high concentration of blood vessels and nerves. Muscle is mainly composed of muscle cells.

Look at the illustration of the structure of a skeletal muscle shown below. Locate these anatomical features of a muscle. Skeletal muscle is arranged in discrete muscles or muscle bellies, an example of which is the biceps brachii. It is connected by tendons to processes of the skeleton.

  • The muscle itself is called the muscle belly and is surrounded by a fascial membrane called the epimysium. Epimysium is a layer of connective tissue which ensheaths the entire muscle.
  • Perimysium is a sheath of connective tissue which groups individual muscle fibers (anywhere between 10 to 100 or more) into bundles or fascicles.
  • The fascicles are made up of muscle spindle fibers or muscle cells, also sometimes called myofibers, which are wrapped in a fascial membrane called endomysium. The endomysium, literally meaning within the muscle, is a layer of connective tissue that ensheaths a muscle fiber and is composed mostly from reticular fibers. Muscle spindles are distributed throughout the muscles and provide sensory feedback information to the central nervous system.
  • Within the cells are myofibrils; myofibrils contain sarcomeres, which are composed of actin and myosin.


deep muscles