THIRD VENTRICLE

THIRD VENTRICLE

The third ventricle is the second of the four connected fluid-filled cavities within the brain. It is located between the two hemispheres of the diencephalon and is a continuation of the lateral ventricles.

• The third ventricle is a narrow, curved cavity that extends from the interventricular foramen to the aqueduct of Sylvius.
• It communicates with the fourth ventricle through the aqueduct of Sylvius.
• The third ventricle is lined by ependyma and is filled with cerebrospinal fluid.
• The choroid plexuses of the third ventricle are located in the roof and produce cerebrospinal fluid.
• The third ventricle is surrounded by the thalamus, hypothalamus, and optic chiasm.
• The mammillary bodies are located in the floor of the third ventricle.
• The third ventricle provides a pathway for cerebrospinal fluid to pass from the lateral ventricles to the fourth ventricle.
• The third ventricle is an important structure in the diagnosis of certain neurological conditions such as hydrocephalus.

Developmental Process:

• The third ventricle is formed from the prosencephalon during embryonic development.
• The prosencephalon divides into the diencephalon and telencephalon, with the third ventricle forming between them.
• The third ventricle continues to develop and grow as the brain develops.

Nerve Supply:

• The third ventricle is innervated by the hypothalamic nuclei and the posterior pituitary.
• The hypothalamus controls the production of cerebrospinal fluid in the third ventricle.

Blood Supply:

• The third ventricle is supplied by branches of the anterior cerebral artery, posterior cerebral artery, and internal carotid artery.
• The choroid plexuses of the third ventricle are supplied by branches of the anterior cerebral artery.

Lymph Drainage:

• The cerebrospinal fluid in the third ventricle is absorbed into the bloodstream through the arachnoid villi.
• The arachnoid villi are located in the dura mater surrounding the third ventricle.

Muscle Action Sequence:

• There is no muscle action sequence associated with the third ventricle.
• The third ventricle is a fluid-filled cavity and does not have any muscles associated with it. THIRD VENTRICLE

Describe the boundaries of the ventricle

• The Third ventricle is a narrow, slit-like cavity in the midline of the brain.
• It is situated between the two lateral ventricles and is bounded by:
  • Dorsally by the thalamus
  • Ventrally by the hypothalamus
  • Laterally by the fornix and the thalamus
  • Medially by the massa intermedia

Explain the features

• The third ventricle is continuous with the fourth ventricle through the cerebral aqueduct.
• It is connected to the lateral ventricles by the interventricular foramina.
• The third ventricle contains the choroid plexus.

Name the structures in the floor of third ventricle

• Optic chiasm
• Infundibulum
• Tuberculum sellae
• Mammillary bodies
• Infundibular stalk

Describe the applied anatomy

• The third ventricle is an important landmark in neuroanatomy.
• It is a common site for neurosurgical intervention.
• The structures surrounding the third ventricle are involved in various neurological disorders, including hydrocephalus, hypothalamic dysfunction, and thalamic lesions.