Lesions & Tracts - Bales

Question 1

Leaves sensory and extrapyramidal input intact; sxs: spastic paralysis, no atrophy

Answer 1

UMN lesion

Question 2

Sxs: hypotonia/atonia, hyporeflexia/areflexia, flaccid paralysis

Answer 2

LMN lesion

Question 3

Progressive death of motor neurons; initial sx are either LMN or UMN, but ultimately mixed

Answer 3

ALS

Question 4

Where in the corticospinal tract (CST) are the giant Betz cells located?

Answer 4

Layer 5

Question 5

Which fibers and from which nucleus cross immediately in ventral segmental decussation of mesencephalon?

Answer 5

Rubrospinal fibers from red nucleus

Question 6

Which fibers and from which nucleus cross immediately in dorsal segmental decussation of mess encephalon?

Answer 6

Tectospinal fibers from superior collicus

Question 7

Which tract is in the ventral funiculus and is excitatory to extensors and inhibitory to flexors?

Answer 7

Pontine reticulospinal tract

Question 8

Which tract is in the lateral funiculus and is inhibitory to extensors and excitatory to flexors?

Answer 8

Medullary reticulospinal tract

Question 9

Contralateral eye turned up and in

Answer 9

Trochlear (CN IV) nerve lesion

Question 10

Sxs: bilateral ptosis, bilateral elevation loss, ipsilateral eye turned out, ipsilateral loss of convergence

Answer 10

Unilateral Oculomotor (CN III) LMN lesion

Question 11

What is the corticonuclear tract (CNT) pathway?

Answer 11

Lower lateral gyrus → genu of PLIC → medial end of middle 3/5 of crus cerebri

Question 12

Sxs: drooping lid, abduction of unopposed lateral rectus, cannot elevate because of inferior oblique and superior rectus palsy

Answer 12

LMN ipsilateral lesion

Question 13

Sxs: elevation weakness

Answer 13

LMN contralateral lesion

Question 14

Sxs: dilated pupil, focusing weakness

Answer 14

E-W nucleus

Question 15

Sxs: Abducted eye & large pupil

Answer 15

CN III + E-W