Lesions

Question 1

When a lesion is found above the decussation in the Medial Lemniscus system, what side will the deficit be?

Answer 1

Contralateral

Question 2

Where is the decussation of the Medial Lemniscus system?

Answer 2

Internal Arcuate Fibers of the Caudal Medulla

Question 3

An ipsilateral deficit from a lesion in the Medial Lemniscus will originate in this area.

Answer 3

Below the internal arcuate fibers of the caudal medulla

Question 4

Lesions in the medial lemniscus of the midbrain cause these type of deficits.

Answer 4

Loss of proprioception, discriminate touch, vibratory sense, pain and thermal sensation on the contralateral upper and lower extremities

Question 5

Lesions at the mid to rostral pons level of the medial lemniscus will cause these deficits

Answer 5

Loss of proprioception, descriminate touch, vibratory sense, pain and thermal sensation on the contralateral upper and lower extremities and ipsilateral side of the face.
Paralysis of the muscles of mastication

Question 6

Lesions at the caudal pons differs from lesions of the mid to rostral pons in this way

Answer 6

Ipsilateral facial and lateral rectus paralysis

Ipsilateral ptosis, miosis and andhidrosis (Horner)

Question 7

In addition to loss of proprioception, discriminative touch and vibratory sense of the contralateral upper and lower extermities, what other deficits will be found with a medial lemniscus at the level of the medulla?

Answer 7

Tongue weakness (deviates toward side of lesion upon protrusion)
Hemiplegia of contralateral upper and lower extremities

Question 8

Lesions in the anterolateral system almost always affect this side of the body.

Answer 8

Contralateral

Question 9

Lesions in the anterolateral system in all levels of the brain stem will have these general deficits

Answer 9

Contralateral loss of pain and thermal sensation of the upper and lower extremities
Loss of proprioception, discriminative touch vibratory sense on the contralateral lower extremities