Anatomy of the Eye and Cranial Nerves Lecture Notes PDF
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Arab Academy for Science and Technology
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Summary
These lecture notes provide an overview of the anatomy of the eye, including the bony orbit, eyeball structure, different components like the fibrous coat and vascular coat, and the nervous coat, muscles of the iris and extraocular eye muscles. This document also covers the cranial nerves involved.
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**Anatomy of the eye and 2^nd^, 3^rd^, 4^th^ and 6th cranial nerves** **[Bony orbit]** **Figure 1. Bony orbit.** **[Eyeball]**  **Figure 2. Eyeball.** *- The optic nerve emerges from the eyeball.* A. **[Fibrous coat...
**Anatomy of the eye and 2^nd^, 3^rd^, 4^th^ and 6th cranial nerves** **[Bony orbit]** **Figure 1. Bony orbit.** **[Eyeball]**  **Figure 2. Eyeball.** *- The optic nerve emerges from the eyeball.* A. **[Fibrous coat :]** B. **[Vascular coat :]** **[3- iris :]** *it is the coloured part taht has a central opening; pupil.* *2- **dilator pupillae :** radial fibers to widen the pupil and has sympathetic supply. **(Figure 2,6)*** C. **[Nervous coat :]** - **[Anterior and posterior chambers :]** ***[- Clinical notes :] (Figure 9)*** [*-* **Anterior and posterior segments***:*] ***(Figure 2)*** **[EXTRAOCCULAR MUSCLES]** \- They include : \- 4 rectus muscles (superior, inferior, medial and lateral). **(fig. 10)** \- 2 oblique muscles (superior and inferior). **(fig. 10)** \- Movements of the eyeball are : elevation, depression, abduction and adduction. **(Figure 11A)** \- As the axis of the orbit is different from the axis of the eyeball, the extraoccular muscles have complicated movements. **(figure 11B)** **Figure 2. Movements and axis of the eyeball and tendinous ring.** +-------------+-------------+-------------+-------------+-------------+ | **Muscle** | **Origin** | **Insertion | **Action** | **Nerve | | | | ** | | supply** | +=============+=============+=============+=============+=============+ | **Superior | Tendinous | All rectus | Elevation | Occulomotor | | rectus** | | muscles are | and | nerve | | | ring | inserted | adduction | | | | | into the | of the | | | | | anterior | eyeball. | | | | | part of the | | | | | | sclera | | | | | | behind the | | | | | | corneo-scle | | | | | | ral | | | | | | junction | | | | | | forming a | | | | | | cone of | | | | | | muscles. | | | +-------------+-------------+-------------+-------------+-------------+ | **Inferior | | | depression | | | rectus** | | | and | | | | | | adduction. | | +-------------+-------------+-------------+-------------+-------------+ | **Medial | | | Adduction. | | | rectus** | | | | | +-------------+-------------+-------------+-------------+-------------+ | **Lateral | | | Abduction. | Abducent | | rectus** | | | | nerve | +-------------+-------------+-------------+-------------+-------------+ | **Superior | posterior | tendon | Depression | Trochlear | | oblique** | part of the | passes | and | nerve | | | roof of | medially | abduction. | | | | orbit | till the | | | | | | trochlea | | | | | | then passes | | | | | | posteriorly | | | | | | to the | | | | | | posterior | | | | | | upper | | | | | | lateral | | | | | | quadrant of | | | | | | the eyeball | | | +-------------+-------------+-------------+-------------+-------------+ | **Inferior | anterior | posterior | Elevation | Occulomotor | | oblique** | part of the | lower | and | nerve | | | floor of | lateral | abduction. | | | | orbit | quadrant of | | | | | | the eyeball | | | +-------------+-------------+-------------+-------------+-------------+ | **Levator | roof of the | upper | Elevation | Occulomotor | | palpebrae | orbit. | eyelid. | of the | nerve. Some | | superioris* | | | upper | muscle | | * | | | eyelid. | fibers | | | | | | (Muller's | | | | | | muscle) | | | | | | receive | | | | | | sympathetic | | | | | | innervation | +-------------+-------------+-------------+-------------+-------------+ **[CRANIAL NERVES INSIDE THE ORBIT ]** \- **[Occulomotor (3^rd^ cranial) nerve :] (Figure 13)** **Figure 13. Cranial nerves supplying the muscles of the eyeball.** \- **[Trochlear (4^th^ cranial) nerve :] (Figure 13)** **[- Origin :]** trochlear nucleus in the midbrain. \- **[Abducent (6^th^ cranial) nerve :] (Figure 13)** **[- Origin :]** abducent nucleus in the pons. ***[- Clinical notes :]*** ***-*** Damage of one optic nerve causes complete blindness of this eye. **- Damage of trochlear nerve :** the eye turns upwards and medially with double vision.
