Answer
Skeletal muscles are attached to bones by extensions of their connective tissue components. There are two methods of attachment--direct and indirect.
1. The direct( fleshy) attachment method.
In this method there is very little space between the "red" muscle tissue (meat) and the bone. To the naked eye, it appears as though the muscle was attached directly to bone. However, microscopic examination will reveal that the muscle fibers do not actually make contact with the bone, but that there is a small space between bone and muscle tissue, and that this space is filled in with collagen fibers.
This kind of direct attachment is found along the origin of the brachialis (distal half of anterior surface of humerus), and along the lateral head of the triceps brachii ( attached to posterior and lateral aspect of humerus).
Work Step by Step
2. In the indirect attachment modality, the muscle ends short of the bone and the space is filled by a fibrous connective tissue structure--the tendon. Examples are the attachments of the biceps brachii : origin--attachment to scapula and insertion-- by the bicipital aponeurosis on the radius and fascia of the forearm.
An aponeurosis is a broad tendon like those beneath the scalp, and those associated with abdominal lumbar, and foot muscles.
One well-known, tendon even to the layman, is the Achille tendon (calcaneal tendon). It can be felt just above the heel.
Generally, collagen fibers from epimysium, perimysium and endomysium continue into the muscle's tendon and thence into the periosteum and matrix of the bone. This structural design establishes a strong and stable continuity from muscle to bone that resists tearing.
