# Skeletal muscle study

Original procedural 3D geometry, not a replacement for the body's native muscles.
The part-detail action opens a named fusiform skeletal-muscle example. Cardiac
muscle, tendons, fascia, ligaments and the iliotibial tract do not use this entry.

Four separate scales/views: whole muscle, cutaway with extended fascicle, enlarged
muscle fiber, and a sarcomere showing opposing thin and central thick filaments.
The extended bundle is illustrative; cell and filament dimensions are magnified.

Epimysium surrounds the whole muscle; perimysium surrounds fascicles; endomysium
surrounds fibers outside the sarcolemma. Peripheral nuclei belong to the muscle
cell. Myofibrils contain repeating sarcomeres with actin anchored to Z discs and
myosin between them. Gross shape and fascicle arrangement vary between muscles.

Swept volumes have closed cut faces. Open membranes have a finite thickness and
closed borders. Procedural longitudinal grain, geometric surface relief and
small tonal variation distinguish flesh and collagen. Transverse bands appear
in the cellular view. Geometry is merged by tissue/material to limit draw calls;
rendering is demand-driven rather than continuously animating a static model.

References:
- https://openstax.org/books/anatomy-and-physiology-2e/pages/10-2-skeletal-muscle
- https://training.seer.cancer.gov/anatomy/muscular/structure.html
- https://www.ncbi.nlm.nih.gov/books/NBK537236/

The offline images in audit/muscle-study are geometry previews, not screenshots
of the production WebGL interface. In-app visual verification remains necessary.