פרק 8 Chapter 8 Disorders of Non- Painful Somatic Sensation Flashcards
לאיזה גרעין בתלמוס מגיעים הסיבים של
ה medial lemniscus
1. Ventero-posterior lateral (VPL)
2. Ventro-post med (VPM)
3. Ventro lateral (VL)
4. Reticular nuclei
5. Pulvinar
- VPL
איזה מסלול חשוב בשביל זיהוי חפצים במישוש?
א.spinothalamic tract
ב. עמודות פוסטריורית
ג.vestibulocerebellar
ד.reticulospinothalamic
ב. עמודות פוסטריוריות
בעמודות האחוריות – רצים הסיבים האחראים על מגע, ויברציה, כיוון תנועה ,מיקום מפרקים, וסטיראואסטסזיה – זיהויי טקסטורה, צורה, מספרים או צורות הנכתבות ע”פ העור two point discrimination.
מהו
Thalamus Syndrome of Dejerine-Roussy
הבדיקה תקינה
Two-Point Discrimination
The ability to distinguish two points from one is tested
by using a compass, the points of which should be blunt
and applied simultaneously and painlessly. The distance
at which such stimuli can be recognized as a distinct pair
varies but is roughly 1 mm at the tip of the tongue, 2 to 3
mm on the lips, 3 to 5 mm at the fingertips, 8 to 15 mm on
the palm, 20 to 30 mm on the dorsal hands and feet, and
4 to 7 em on the trunk. It is characteristic of the patient
with a lesion of the sensory cortex to mistake two points
for one, although occasionally the opposite occurs.
Table 8-2
ORIGIN OF ABERRANT SENSATIONS (7)
Table 8-1SENSORY RECEPTORS RESPONSIBLE FOR DETECTION OF TOUCH
Table 8-3
EXAMINATION FEATURES OF THE PERIPHERAL AND SPINAL
CORD SENSORY SYNDROMES
Figure 8-1. The cutaneous fields of peripheral nerves. (Reproduced by permission from Haymaker W, Woodhall B: Peripheral Nerve Injuries,
2nd ed. Philadelphia, Saunders, 1953.)
Figure 8-2. The location and morphology of mechanoreceptors in hairy and hairless (glabrous) skin of the human hand.
Receptors are located in the superficial skin, at the junction of the dermis and epidermis, and more deeply in the dermis and subcutaneous tissue.
The receptors of the glabrous skin are Meissner’s corpuscles, located in the dermal papillae; Merkel disc receptors, located between the dermal papillae; and bare nerve endings.
The receptors of the hairy skin are hair receptors, Merkel’s receptors (having a slightly different organization than their counterparts in the glabrous skin), and bare nerve endings. Subcutaneous receptors, beneath both glabrous and hairy skin, include Pacinian corpuscles and Ruffini endings. Nerve fibers that terminate in the superficial layers of the skin are branched at their distal terminals, innervating several nearby receptor organs; nerve fibers in the subcutaneous layer innervate only a single receptor organ. The structure of the receptor organ determines its physiological function. (Reproduced with permission from Kandel ER, Schwartz JH, Jessell TM: Principles of Neural Science, 4th ed. New York: McGraw-Hill, 2000.)
הרצפטורים השונים של תחושה
Figure 8-3. Distribution of the sensory spinal roots on the surface of the body (dermatomes). (Reproduced by permission from Sinclair D: Mechanisms of Cutaneous Sensation. Oxford, UK, Oxford University
Press, 1981.)
Figure 8-4. Dermatomes of the upper and lower extremities, outlined by the pattern of sensory loss following lesions of single nerve roots. (Reproduced by permission from Keegan and Garrett.)
Figure 8-5. The main somatosensory pathways emphasizing the posterior column–lemniscal system (thicker tract lines). See Fig. 7-2 for comparison with the spinothalamic system.
Figure 8-6. The “sensory homunculus,” or cortical representation of sensation in the postcentral gyrus; compare this to the distribution of body areas in the motor cortex as shown in Fig. 3-4. (Reproduced with permission from Kandel ER, Schwartz JH, Jessel TM: Principle of Neural Science, 4th ed. New York, McGraw-Hill, 2000.)
Figure 8-7. Sites of lesions of the characteristic spinal cord sensory syndromes (shaded areas indicate regions of damage). Lower right figure
shows variable extent of damage to mid-axial cord but always sparing the posterior columns.
