Location and Structure of the Oculomotor Nucleus
- The oculomotor nucleus is located in the midbrain.
- It lies in the gray substance of the floor of the cerebral aqueduct.
- The nucleus extends in front of the aqueduct for a short distance into the floor of the third ventricle.
- Fibers of the oculomotor nerve arise from this nucleus.
- The nucleus is divided into anterior and posterior groups.

Pathway of the Oculomotor Nerve
- The fibers of the oculomotor nerve pass forward through the tegmentum, the red nucleus, and the medial part of the substantia nigra.
- They form a series of curves with a lateral convexity.
- The fibers emerge from the oculomotor sulcus on the medial side of the cerebral peduncle.
- The oculomotor nerve does not consist of a continuous column of cells but is broken up into smaller nuclei.
- The posterior group of nuclei is symmetrical on both sides, while the anterior group consists of two nuclei.

Physiological Subdivisions of the Oculomotor Nucleus
- The oculomotor nucleus can be subdivided into smaller groups of cells.
- Each group controls a particular muscle.
- This subdivision allows for precise control of eye movements.
- The oculomotor nucleus is responsible for coordinating the movements of multiple eye muscles.
- Dysfunction of the oculomotor nucleus can result in various eye movement disorders.

Role of the Edinger-Westphal Nucleus
- The Edinger-Westphal nucleus is located dorsal to the main oculomotor nucleus.
- It is responsible for the autonomic functions of the oculomotor nerve.
- The Edinger-Westphal nucleus controls pupillary constriction.
- It also regulates lens accommodation, allowing the eye to focus on near objects.
- Dysfunction of the Edinger-Westphal nucleus can lead to pupillary abnormalities and impaired lens accommodation.

Additional Images and External Links
- The article includes additional images related to the oculomotor nucleus.
- These images illustrate the anatomical features and central connections of the oculomotor nerve.
- External links provide further resources for studying the oculomotor nucleus.
- The University of Michigan Health System offers an atlas image of the brainstem and cranial nerve nuclei.
- The BrainMaps project provides stained brain slice images that include the oculomotor nucleus.