Tuesday, 4/19-Tactile And Proprioceptive Pathways (Stephens)

Question 1

Fill in the blanks for the following regarding the Ventral Spinothalamic pathway:

The central processes of the primary neurons course through the medial division of the dorsal root, enter the __ of the SC, and bifurcate into ascending and descending fibers. The primary axons will ascend 6-10 segments while sending numerous collateral terminals to secondary neurons in the ipsilateral nucleus proprius and intermediate gray.

The secondary axons will cross in the AWC and form an ascending tract called the ___. In the medulla, it will join with the LSTT and spinotectile fibers to form the ___.

Answer 1

Posterior funiculus

VSTT

SL

Question 2

Fill in the blanks for the following regarding the ventral spinothalamic pathway:

The SL terminates on tertiary neurons in the ___ and will project to the ___

Answer 2

VPLN

Primary somesthetic cortex

Question 3

This pathway follows the general scheme of a conscious sensory pathway. It is used for PROPRIOCEPTION, 2-PT TACTILE DISCRIMINATION and VIBRATORY SENSATIONS.

Answer 3

Posterior column/medial lemniscus system

Question 4

Fill in the blanks for the Posterior Column/Medial Lemniscal system:

The primary axons from the LE will form and ascend in the ___ while the primary axons from the UP will form and ascend in the ___.

In the medulla, the primary axons conveying sensory info from the LE will terminate in the ___ while the primary axons conveying sensory info from the UE will terminate in the ___

Answer 4

Fasciculus gracilis

Fasciculus cuneatus

Nucelus gracilis (clavum)

Nucleus cuneatus (tuberculum cuneatum)

Question 5

Fill in the blanks for the Posterior Column/Medial Lemniscus system:

In the medulla, the secondary axons from the nucleus gracilis and cuneatus decussate as internal arcuate fibers and form the contralateral ___.

Answer 5

Medial lemniscus

Question 6

Fill in the blank regarding the Posterior Column/Medial Lemniscus system:

Secondary neurons from the ML ascends and terminate in the ___. The tertiary axons will then project to the ___

Answer 6

VPLN

Primary somesthetic cortex

Question 7

The postcentral gyrus is somatotopically organized with the head region adjacent to the ___, the knee region located ___, and the leg and foot regions on the ___

Answer 7

Lateral fissure

At the top of the gyrus

Paracentral lobule

Question 8

The ___ tract conveys precise coordination, postural adjustments and precise movements of individual muscles of the LOWER limbs and body

Answer 8

Dorsal spinocerebellar tract (DSCT)

Question 9

The ___ tract conveys gross postural adjustments and overall proprioception of the LOWER limb

Answer 9

Ventral spinocerebellar tract (VSCT)

Question 10

In the VSCT, primary axons arise from ___ of the SC, terminate on scattered cells in the base of the dorsal horn and intermediate gray.

In the VSCT, the secondary axons will decussate in the ___ and ascend in the contralateral ventral spinocerebellar tract and course through the ___ in the cerebellar cortex of the vermis.

Answer 10

Lumbosacral levels

Anterior white commissure

Superior cerebellar peduncle

Question 11

In the DSCT, the primary central processes from C8-L3 SN’s terminate on cells in the ___ of the thoracic SC.

In the DSCT, the secondary axons ascend in the ipsilateral lateral funiculus of the SC as the DSCT. The DSCT ascends to the medulla, courses through the __ and terminates in the cerebellar cortex of the vermis

Answer 11

Nucleus dorsalis

Inferior cerebellar peduncle

Question 12

In the DSCT, proprioception and exteroceptive info from the L4-S5 SN’s must ascend in the __ before terminating in the nucleus dorsalis

Answer 12

Fasciculus gracilis

Question 13

This tract conveys unconscious cerebellar modalities for precise proprioception of individual muscles in the lower extremities

Answer 13

DSCT

Question 14

This tract conveys unconscious cerebellar modalities for gross proprioception of the whole lower extremities

Answer 14

VSCT

Question 15

This tract conveys unconscious cerebellar modalities for precise proprioception of individual muscles in the upper extremity

Answer 15

Cuneocerebellar tract

Question 16

A unilateral lesion of the SL results in:

Answer 16

Contralateral hemianalgesia and thermal hemianesthesia. The loss of passive touch may be masked by the intact posterior column/medial lemniscal system

Question 17

Complete unilateral lesions of the posterior columns result in:

Answer 17

Ipsilateral loss of proprioception, 2-pt tactile discrimination and vibratory sensations below to the level of the lesion

Question 18

A lesion of the fasciculus gracilis results in:

Answer 18

Ipsilateral loss of proprioception, 2-pt tactile discrimination and vibratory sensations from the lower 1/2 of the body and LE.

Question 19

A lesion of the fasciculus cuneatus results in:

Answer 19

Ipsilateral loss of proprioception, 2-pt tactile discrimination and vibratory sensations from the upper 1/2 of the body and UE.

Question 20

Unilateral lesions of the ML results in:

Answer 20

Loss of proprioception, 2-pt tactile discrimination and vibratory sensations on the OPPOSITE side of the body and limbs

Question 21

__ is a meningovascular inflammation of the BV’s as they pierce through the pia at the junction of the dorsal rootlets and the posterior columns. The lumbosacral nerves and SC segments are most frequently affected. This occurs during the tertiary (late) stage of syphilis and results in bilateral ischemic necrosis of the posterior columns and the dorsal roots at this level.

Answer 21

Tabes dorsalis

Question 22

A positive Romberg test suggests:

Answer 22

Involvement of the posterior columns and/or cerebellum

Standing with feet together and arms extended in front, the patient will fall when closing their eyes

Question 23

This pathway conveys light (passive) touch, crude tactile sensations and pressure:

Answer 23

Ventral spinothalamic pathway