CLINICAL ANATOMY

ABDOMENCEREBELLUMKhaleel Alyahya, PhD, MEd

www.khaleelalyahya.net

RESOURCES

Atlas of Human AnatomyFrank Netter

Clinical AnatomyRichard Snell

Gray’s AnatomyDrake, Vogl & Mitchell

INTRODUCTION

▪ The cerebellum stands for little brain.

▪ It is a structure within the central nervous system.

▪ It has an important role in motor control, with cerebellar dysfunctionoften presenting with motor signs.

▪ In particular, it is active in the coordination1, precision2 and timingof movements3, as well as in motor learning4.

By Khaleel Alyahya, PhD, MEd

LOCATION

▪ The cerebellum is located at the back of the brain inferiorto occipital and temporal lobe, and within the posterior cranialfossa.

▪ It is separated from these lobes by the tentorium cerebelli, a toughlayer of dura mater.

▪ It lies at the same level of the pons posteriorly, from which it isseparated by the fourth ventricle.

▪ Posterior and lateral to the cerebellum are the occipital bone andits overlying layer of dura mater.

By Khaleel Alyahya, PhD, MEd

ANATOMICAL STRUCTURE

▪ The cerebellum consists of two hemispheres which are connectedby the vermis, a narrow midline area.

▪ Like other structures in the CNS, the cerebellum consists of greymatter and white matter:

• Grey matter located on the surface of the cerebellum. It is tightlyfolded, forming the cerebellar cortex.

• White matter located underneath the cerebellar cortex. Embedded inthe white matter are the four cerebellar nuclei.

o dentate, emboliform, globose, and fastigi nuclei.

By Khaleel Alyahya, PhD, MEd

DIVISIONS

▪ There are three ways that the cerebellum can be subdivided.

• Anatomical lobes

• Zones

• Functional divisions

By Khaleel Alyahya, PhD, MEd

ANATOMICAL LOBES

▪ There are three anatomical lobes that can be distinguished in thecerebellum:

• The anterior lobe

• The posterior lobe

• The flocculonodular lobe

▪ These lobes are divided by two fissures:

• The primary fissure

• The posterolateral fissure

By Khaleel Alyahya, PhD, MEd

CEREBRAL LOBES

▪ The anterior lobe extends from the level of the cerebellarpeduncles anteriorly and includes the anterior two-thirds of thesuperior vermis, along with the anterior third of each hemisphere.This lobe terminates at the primary fissure.

▪ From this point posteriorly and laterally and continuing along theinferior surface to the posterolateral fissure is the larger posteriorlobe.

▪ The flocculonodular lobe is a flattened lobe that lies betweenthe posterolateral fissure (inferiorly) and the inferior medullaryvelum and the cerebellar peduncles (superiorly).

By Khaleel Alyahya, PhD, MEd

ZONES

▪ There are three cerebellar zones.

▪ In the midline of the cerebellum is the vermis.

▪ Either side of the vermis is the intermediate zone.

▪ Lateral to the intermediate zone are the lateral hemispheres.

▪ There is no difference in gross structure between the lateralhemispheres and intermediate zones

By Khaleel Alyahya, PhD, MEd

FUNCTIONAL DIVISIONS

▪ The cerebellum can also be divided by functions.

▪ There are three functional areas of the cerebellum:

• The cerebrocerebellum

• The spinocerebellum

• The vestibulocerebellum

By Khaleel Alyahya, PhD, MEd

CEREBROCEREBELLUM

▪ The largest division.

▪ Formed by the lateral hemispheres.

▪ It is involved in planning movements and motor learning.

▪ It receives inputs from the cerebral cortex and pontine nuclei andsends outputs to the thalamus and red nucleus.

▪ This area also regulates coordination of muscle activation and isimportant in visually guided movements.

By Khaleel Alyahya, PhD, MEd

SPINAOCEREBELLUM

▪ Comprised of the vermis and intermediate zone of the cerebellarhemispheres.

▪ This region is responsible for the maintaining balance.

▪ It is involved in skilled, volitional movements.

▪ It also receives proprioceptive information.

▪ It consists of the lobes near the midline.

By Khaleel Alyahya, PhD, MEd

VESTIBULOCEREBELLUM

▪ The functional equivalent to the flocculonodular lobe.

▪ It is involved in controlling balance and ocular reflexes, mainlyfixation on a target.

▪ It receives inputs from the vestibular system and sends outputsback to the vestibular nuclei.

By Khaleel Alyahya, PhD, MEd

CEREBELLAR PEDUNCLES

▪ There are three-foot processes that not only anchor thecerebellum to the brainstem, but also provide a pathway forneuronal tracts to travel to and from the cerebellum.

▪ These structures are the superior, middle and inferior cerebellarpeduncles.

▪ The following are connections between the cerebellum and therespective parts of the brainstem:

• To midbrain: superior cerebellar peduncles

• To pons: middle cerebellar peduncles

• To medulla: inferior cerebellar peduncles

By Khaleel Alyahya, PhD, MEd

BLOOD SUPPLY

▪ The cerebellum receives its blood supply from three pairedarteries:

• Superior cerebellar artery (SCA)

• Anterior inferior cerebellar artery (AICA)

• Posterior inferior cerebellar artery (PICA)

▪ The SCA and AICA are branches of the basilar artery, whichwraps around the anterior aspect of the pons before reaching thecerebellum.

▪ The PICA is a branch of the vertebral artery.

By Khaleel Alyahya, PhD, MEd

VENOUS DRAINAGE

▪ Venous drainage of the cerebellum is by the superior and inferiorcerebellar veins.

▪ Then they drain into:

• The superior petrosal sinuses

• The transverse sinuses

• The straight dural venous sinuses.

By Khaleel Alyahya, PhD, MEd

CLINICAL NOTES

▪ Damage to the cerebellum often causes motor-related symptoms.

▪ It depends on the part of the cerebellum involved and how it isdamaged.

▪ Damage to the flocculonodular lobe may show loss of equilibriumby difficulty in balancing (irregular walking gait).

▪ Damage to the cerebrocerebellum will cause problems with

planned movements.

▪ Spinocerebellum damage will lead to a truncal ataxia.

▪ Damage to the lateral zone typically causes problems in skilled

voluntary and planned movements which can cause errors in the

force, direction, speed and amplitude of movements.

By Khaleel Alyahya, PhD, MEd

QUESTIONS?