24: Brain 2

What divisions of the brain are associated with the forebrain

Telencephalon and diencephalon

What divisions of the brain are associated with the mibrain

Mesencephalon

What divisions of the brain are associated with the hindbrain

Metencephalon and myelencephalon

What brain structures are associated with the telencephalon

Cerebrum

What brain structures are associated with the diencephalon

Thalamus and hypothalamus

What brain structures are associated with the mesencephalon

Midbrain

What brain structures are associated with the metencephalon

Pons and cerebellum

What brain structures are associated with the myelencephalon

Medulla

What brain cavities are associated with the telencephalon

Lateral ventricles

What brain cavities are associated with the diencephalon

III ventricle

What brain cavities are associated with the mesencephalon

Mesencephalic aqueduct

What brain cavities are associated with the metencephalon

½ of the IV ventricle

What brain cavities are associated with the myelencephalon

½ of the IV ventricle

What cranial nerves are associated with the telencephalon

CN I

What cranial nerves are associated with the diencephalon

CN II

What cranial nerves are associated with the mesencephalon

CN III and IV

What cranial nerves are associated with the metencephalon

CN V

What cranial nerves are associated with the myelencephalon

CN VI-XII

What division is the corona radiata unique to

Telencephalon (cerebrum)

Connection between the cerebral hemispheres

Corpus callosum

Ventricles of the telencephalon

Lateral ventricles

Site of rabies in the telencephalon

Hippocampus

Key clinical signs of cerebral disease

Altered consciousness

Regions of the brain in the diencephalon

• Thalamus

• Hypothalamus

• Pituitary gland (attached via infundibular stalk)

Optic nerve structure on the ventral aspect of the diencephalon

Optic chiasm

Location of the hypothalamus

Just ventral to the thalamus, surrounds the infundibulum of the pituitary gland

What part of the pituitary gland communicates with the III ventricle

Diverticulum in the stalk

Hypothalamus function

UMN nucleus for the ANS

Thalamus function

Relay center for signals from the spinal cord and brain stem

What connects the two halves of the thalamus

Interthalamic adhesion

Key clinical signs of diencephalon disease

• Altered consciousness

• Issues with the optic nerve

• Contralateral posture issues with normal gait

• Possibly endocrine disorders

Spaces and nuclei in the mesencephalon

• Mesencephalic aqueduct

• Oculomotor nucleus (LMN)

• PS-ANS nucleus of CN III (ANS LMN)

• Trochlear nucleus (LMN)

Clinical signs of mesencephalic disease

• Altered consciousness

• Contralateral postural defects

• Normal gait

• CN III LMN signs

• CN IV LMN signs

Key causes of cerebellar hypoplasia

• In utero infection

• Malnutrition or poisoning during development

Clinical signs of cerebellar hypoplasia

Loss of motor coordination

What connects the cerebellum to the pons/brainstem

Cerebellar peduncles

What makes up the middle cerebellar peduncle

Transverse pontine fibers on the ventral aspect

What ventricle is associated with the metencephalon

IV ventricle (1/2)

Line on the floor of IV ventricle

Median sulcus

Clinical signs of pons disease

• Ipsilateral CN V LMN signs

• Ipsilateral Generalized UMN signs

• Ipsilateral postural defects

Ventricle associated with the myelencephalon

IV ventricle (1/2)

Longitudinal fibers that run caudal to the pons

Pyramids

Transverse fibers that run caudal to the pons and “under” the pyramids

Trapezoid body

Caudal ending of the IV ventricle → central canal

Obex

Clinical signs of myelencephalon disease

• Ipsilateral postural defects

• Gait abnormalities

• Ipsilateral UMN signs

• Ipsilateral LMN signs in CN VI-XII

• Vestibular signs if CN VIII is involved

Venous drainage of the head

• External jugular

• Maxillary

• Linguofacial

• Lingual

• Facial

• Deep facial

• Dorsal nasal

• Angularis oculi