Topic 1 Motor cortex and motor pathways

Question 1

Brodmans number for Primary motor area
Brodmans number for Premotor area
Brodmans number for Broccas area

Answer 1

Brodmans 4 (Precentral gyrus)
Brodmans 6
Brodmans 44, 45

Question 2

List the major descending pathways (
(The pyramidal system)
Monosynaptic

Answer 2

• Corticospinal
• Lateral corticospinal 85%
• Ventral corticospinal 15%

*Corticobulbar

Question 3

Corticospinal tract

Answer 3

**LATERAL CORTICOSPINAL TRACT 85%
Skilled volintary movements of limbs

CROSSED > crosses in brainstem at decussation of pyramids

VENTRAL CORTICOSPINAL TRACT
Control of axial muscles

UNCROSSED> crosses at spinal level where it exits

Pathway
Cell bodies in cerebral cortex of frontal & parietal lobes
Through posterior limb of internal capsule
Through cerebral peduncles, pons, pyramids of medulla
85% fibres cross at pyramidal decussation to form contralat LATERAL corticospinal tract.

Terminate in ventral horn of sc