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A jugular foramen is one of the two (left and right) large foramina (openings) in the base of the skull, located behind the carotid canal. It is formed by the temporal bone and the occipital bone . It allows many structures to pass, including the inferior petrosal sinus , three cranial nerves , the sigmoid sinus , and meningeal arteries.
Innervates the superior oblique muscle, which depresses, abducts, and intorts the eyeball. V Trigeminal: Both sensory and motor Pons: Three Parts: V 1 (ophthalmic nerve) is located in the superior orbital fissure V 2 (maxillary nerve) is located in the foramen rotundum. V 3 (mandibular nerve) is located in the foramen ovale.
Parasympathetic activation of the M3 muscarinic receptors causes ciliary muscle contraction, the effect of contraction is to decrease the diameter of the ring of ciliary muscle. [5] The parasympathetic tone is dominant when a higher degree of accommodation of the lens is required, such as reading a book.
The ciliary muscle is an intrinsic muscle of the eye formed as a ring of smooth muscle [3] [4] in the eye's middle layer, the uvea (vascular layer). It controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humor into Schlemm's canal .
The extraocular muscles, or extrinsic ocular muscles, are the seven extrinsic muscles of the eye in humans and other animals. [1] Six of the extraocular muscles, the four recti muscles, and the superior and inferior oblique muscles, control movement of the eye. The other muscle, the levator palpebrae superioris, controls eyelid elevation.
Intrinsic ocular muscles [1] or intraocular muscles [2] are muscles of the inside of the eye structure. The intraocular muscles are responsible for the protraction and retraction of the eyelids and reaction to light and pupil accommodation. [2] They're different to the extraocular muscles that are outside of the eye and control the external ...
Extending lateralward from the posterior half of the condyle is a quadrilateral plate of bone, the jugular process, excavated in front by the jugular notch, which, in the articulated skull, forms the posterior part of the jugular foramen. The jugular notch may be divided into two by a bony spicule, the intrajugular process, which projects ...
Changes in contraction of the ciliary muscles alter the focal distance of the eye, causing nearer or farther images to come into focus on the retina; this process is known as accommodation. [1] The reflex, controlled by the parasympathetic nervous system , involves three responses: pupil constriction, lens accommodation, and convergence.