Iris dilator muscle the superior orbital fissure. From there, they travel with the nasociliary nerve and then the long ciliary nerve. They then pierce the sclera, travel between sclera and choroid to reach the iris dilator muscle. They will also pass through ciliary ganglion and travel in short ciliary nerves to reach the iris dilator muscle. The pupillary dilator acts to increase the size of the pupil to allow more light to enter the eye. It works in opposition to the pupillary constrictor. Pupil dilation occurs when there is insufficient light for the normal function of the eye, and during heightened sympathetic activity,
In vitro muscle testing appropriate magnification level is required due to the dexterity required for isolation of muscles. An external, fibre optic light source is also beneficial to provide sufficient light without the emission of heat. There is no correct approach for the preparation of muscles for testing, as long as the muscle is not damaged during preparation, the muscle-tendon unit is intact and there is something that can be used to anchor the muscle within the testing rig. Pieces of bone can be left at the proximal and/or distal end of skeletal muscles to allow for anchoring. In addition, silk sutures or aluminium