Cerebellum

INTRODUCTION

the cerebellum is a small structure with a highly folded grey mater that plays role in the control of tone and the posture of our body at the same side.

It is an infratentorial structure that controls voluntary movement.

RELATION

ANTERIOR:

1. fourth ventricle,

2. pons,

3. medulla.

POSTERO-INFERIOR:

1. squamous occipital bone

SUPERIOR:

1. tentorium cereberi

MORPHOLOGICAL FEATURES

The cerebellum has 3 morphological divisions:

1. Archicerebellum

• oldest part

• made by the flocullonodular lobe and the lingua

2. Paleocerebellum

• anterior lobe

• uvula

• pyramid

• inferiro vermis

3. Neocerebellum

• newest part of cerebellum to develope

• posteriro lobe

• middle lobe

EXTERNAL FEATURES

The cerebellum is divided into two cerebellar hemispheres - right and left, They control the movement of the respective sides. The two hemispheres are continues with each other and are connected through the vermis.

Each hemisphere is divided into three-lobe:

1. Anterior lobe.

anterior-most part that lies in the anterior part of the superior part of the cerebellum.

It is separated from the middle lobe by the fissure prima.

2. Middle lobe.

It is separated from the anterior lobe by the fissure prima and the posterior lobe by the

posterolateral fissure.

3. Posterior lobe.

It lies in the posterior inferior part of the cerebellum, It lies behind the posterolateral fissure.

4. flocculonodular lobe.

The smallest lobe of the cerebellum present in the inferior surface of the posterolateral

fissure.

It has 2 surfaces - superior and inferior surfaces that continue with each other.

FUNCTIONAL DIVISION OF CEREBELLUM

functionally the anterior and posterior lobe of the cerebellum is divided laterally into 3 longitudinal zones called a lateral zone, intermediate zone, and vermis.

lateral zone.

• connected with the association area.

• involved in planning and programming muscular activity.

Intermediate Zone.

• associated with the control of muscles of limbs

Vermis.

• associated with the control of muscles of the trunk, neck, shoulder, and hips.

Flocculonodular lobe.

• functions with the vestibular system to control equilibrium.

CONNECTIONS OF CEREBELLUM

The cerebellum has bands of fibers that enter and leave the cerebellum.

These fibers are grouped to form three peduncles

1. Superior Peduncle

2. Middle Peduncle

3. Inferior Peduncle

GREY MATER OF CEREBELLUM

Four pairs of nuclei are present in the cerebellum.

1. Nucleus Dentaus - neocerebellar

2. Nucleus Globosus.

3. Nucleus Emboliformis - Paleocerebellar.

4. Nucleus Fastigii - archicerebellar

FUNCTIONS OF CEREBELLUM

• controls tone posture and equilibrium.

• It corrects and modifies the motor information and modifies ongoing movement through thalamocortical, reticospinal and rubospinal tract .

• Neocerebellum finetunes motor movement