1. Motor Pathways
Dr Ayman G. Abu-Tabanja

2. Upper Motor neurons:
Supra spinal neurons whose axons
descend in bundles (descending tracts)
that innervate lower motor neurons
Lower motor neurons: Motor neurons whose cell bodies are
situated in the anterior horn of the
spinal cord or motor nuclei of cranial nerves and whose axons innervate
skeletal muscles

3. Motor Pathways

4. Lateral Corticospinal Tract
Direct motor pathway
Contralateral innervation of LMN
LMN Innervates the trunk and Upper and Lower limbs
Voluntary, discrete
& skilled movements

5. Posterior limb of internal capsule
Cerebral peduncle in midbrain
Basal part of Pons
Pyramid in medulla
Motor Decussation in rostral medulla
Lateral Funiculus

6. Corticobulbar Tract Direct Motor Pathway UMN innervate LMN bilaterally
Exception:
Facial motor nucleus which supply
the muscles of the lower part of
the Face
Hypoglossal motor nucleus which
supply genioglosus

9. Somatotopic Representation
of Corticospinal & Corticobulbar
Fibers

10. Upper & Lower Motor Neurons Lesions
Upper motor neurons lesion:
Location
Signs:
Paralysis or paresis
Hypertonia
Abnormal reflexes
Exaggerated reflexes
Muscle atrophy is not common

11. Plantar flexion Versus Dorsal flexion

12. Upper & Lower Motor Neurons Lesions
Location
Signs:
Paralysis
Hypotonia
Loss of reflexes
Muscular fasciculations
Muscle atrophy
Muscle contracture

13. Upper & Lower Motor Neurons Lesions of the face
Upper motor neurons lesion
Signs:
Paralysis of Contralateral lower quadrant of face
Lower motor neurons lesion:
Location: motor nucleus of facial nerve
Paralysis of Ipsilateral half of face

14. Reticulospinal tract Originate from reticular formation In brainstem
Facilitate or inhibit voluntary
muscle activity

15. Tectospinal Tracts Originate from superior colliculus
Upper cervical segments
Cross medline (most fibers)
Reflex postural movements of the head
in response to visual stimuli

16. Rubrospinal Tract Originate from red nucleus Cross medline immediately
Facilitate Flexors
Inhibit Extensors

17. Vestibulotospinal Tracts
Originate from vestibular nuclei
Facilitate Extensors
Inhibits Flexors
Maintenance of balance

18. Lesions to extrapyramidal tract
Severe Paralysis
Spasticity
Exaggerated deep muscle reflexes
Clasp knife reaction