# What are some examples of fusiform muscles

## Feathering

English: Pennate muscles

### 1 definition

As Feathering refers to the arrangement of the muscle fibers in a muscle in relation to its tendon.

### 2 classification

In terms of their feathering, muscles can be divided as follows:

Muscles whose fibers have no feathering are called parallel-fiber muscles.

### 4 physiology

The strength of a muscle Fm is calculated from the physiological cross-section and is approximately 40 N / cm². For a parallel-fiber muscle, the force transferred to the tendon is F.s (= Tendon force) directly proportional to the anatomical cross-section

In a feathered muscle, this tendon force is changed by the cosine factor of the feathering angle.

Through the feathering of the muscle fibers, a larger physiological cross-section is achieved. The muscle strength of a muscle is about 40 N / cm². If, for example, the anatomical cross-section were tripled through a feathering, the muscle strength would also be tripled. By pinning the muscle fibers, the overall muscle strength increases, and with it the force F transferred to the tendons).

### 4.1 Sample calculation

Assume that the physiological cross-section of a muscle is tripled by the pinning of the muscle fibers. The anatomical cross-section is 10 cm². Due to the feathering of the fibers, the physiological cross-section is now 30 cm². With a feathering angle of 45 °, the tendon force would only be 70% of the force of a parallel-fiber muscle of the same length, since cos (45 °) = 0.7. However, by tripling the physiological cross-section, the muscle strength triples.

so

• F.s = (10 cm² x 3) x 40 N x 0.7