Region: Eye


3D video anatomy tutorial on the anatomy of the eyeball

Eyeball anatomy

Inferior Oblique Muscle of the Eye

Inferior Oblique Muscle of the Eye The structure indicated is the inferior oblique muscle of the eye. This muscle is one of six muscles that are involved in the movements of the eye. The muscles which move the eye are referred to as the extraocular muscles, these include: Superior rectus Inferior rectus Lateral rectus Medial rectus Superior oblique Inferior oblique The oculomotor nerve innervates the superior, inferior and medial rectus muscles as well as the inferior oblique muscle. The trochlear nerve innervates the superior oblique muscle The abducent nerve innervates the lateral rectus muscle. When the inferior oblique muscle is …

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inferior oblique

Orbicularis Oculi

Orbicularis Oculi The structure indicated is the orbicularis oculi muscle of the face. The orbicularis oculi muscle is one of the muscles of facial expression belonging to the orbital group. The muscles of facial expression can be organised into functional groups to provide a more structured approach to understanding the muscles. The functional groups include the following: Orbital group Nasal group Oral group Other The orbicularis oculi muscle is the principle muscle of the orbital group of facial muscles and consists itself of two parts: Palpebral part Orbital part There is an additional muscle in the orbital group – the …

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Orbicularis Oculi

Levator Palpebrae Superioris

Levator Palpebrae Superioris The structure indicated is the levator palpebrae superioris muscle. The levator palpebrae superioris muscle is located in the upper eyelid and is responsible for raising the eyelid. Just like the rectus muscles, and oblique muscles of the eyeball, the levator palpebrae superioris muscle is innervated by the oculomotor nerve (cranial nerve III). The eyelids themselves are supported by the tarsus – in the upper eyelid the superior tarsus, and in the lower eyelid, the inferior tarsus. These structures consist of dense connective tissue. Origin: Roof of the orbit on sphenoid bone, above the optic foramen Insertion: Anterior …

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levator palpebrae superioris

Ciliary Body

Ciliary Body The structure indicated is the ciliary body. The eyeball consists of a fibrous outer layer, a vascular layer, and an inner layer. The vascular layer of the eyeball consists of: Choroid Ciliary body Iris The ciliary body is triangular in cross-section and encircles the eyeball. It has two components: Ciliary muscle Ciliary processes The ciliary body has three main functions: Accommodation of the lens Production and resorption of aqueous humor Maintenance of lens zonules

Ciliary Body

Optic Tract

Optic Tract The structure indicated is the optic tract. The pathway of light from the retina to the occipital cortex is as follows: Retina Optic nerve Optic chiasm Optic tract Lateral geniculate body Optic radiation Occipital cortex There are two optic tracts, a right and a left optic tract. The optic tract is an extension of the optic nerve, conveying information from the optic chiasm to the lateral geniculate nucleus. The optic tracts convey information from the opposite visual field – the right optic tract will convey information from the left visual field, and vice versa. The right optic tract …

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Optic Tract

Superior Oblique Muscle

Superior Oblique Muscle The structure indicated is the superior oblique muscle. The superior oblique muscle is one of the extra-ocular muscles. The extra-ocular muscles include the medial, lateral, superior and inferior recti muscles, and the superior and inferior oblique muscles. Origin: Annulus of Zinn Insertion: Outer posterior quadrant of the eyeball Innervation: Trochlear nerve Action: Moves the eyeball down and out (depression, abduction, medial rotation). The superior oblique muscle inserts onto the eyeball via a long tendon which loops around a pulley (the trochlea of the superior oblique) on the medial aspect of the orbital roof, just lateral to the …

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Superior Oblique Muscle