Muscles and Their Function

A die is illustrated, having two opposite sides inclined against the other sides; however, they remain parallel to each other. These inclined sides are found at the ends of the muscle's abdomen, starting where the head and tail begin, which Steno considers as representing tendons. Each of these should resemble a triangular pillar, which is a shape with three flat rectangular sides; two running towards the upper muscle, and the third below between the two previously mentioned: These triangular sides rest on two parallel triangular foundations, which concern the shape.

Furthermore, Steno states that the flesh, or the abdomen of the muscle, is nothing more than an assembly of thick, coarse threads, called motion-threads; they lie parallel to each other and are held together by very fine transverse threads, which are attached to the outer casing of the muscle. Each of these coarse motion-threads consists of countless finer threads, which are overlain upon one another to make up the coarse threads. These coarse threads would each have the same structure individually as the entire muscle's abdomen, with a thinner and finer thread at both ends of each coarse thread, tightly packed together to form a tendon at each end. Consequently, the coarse threads making up the abdomen and the finer threads forming tendons differ from each other in resistance, thickness, and color.

Translation Notes

Scheuynse Zijden: Inclined sides
Buyk des Muskels: Muscle's abdomen
Pesen: Tendons
Drykante Grond-vlakten: Triangular foundations
Beweegh-Draden: Motion-threads
Dwers-Draadjes: Transverse threads
Rok der Spier: Outer casing of the muscle