Clincal Examples:
Peripheral Nervous System (continued)
| Example 2 |
Figure 5.12 |
The patient reports a loss of sensation along the lateral aspect of his left arm that extends down to include the thumb of his left hand.
Symptoms. The patient complains of a loss of sensation along the side of his left arm that extends down to include the thumb of his left hand (Figure 5.12). Physical examination determines that there are decreases in the abilities to detect vibration and position involving the left elbow and thumb and loss of touch and pain sensations along the lateral edge of the left arm down to the thumb. Touch, vibration, position, and pain sensations are normal for the rest of the body and face.
You conclude that the somatosensory losses in his left arm involve
- discriminative touch and proprioception
- pain sensation
Pathway(s) Affected: You conclude that structures in the following somatosensory pathways (Figure 5.8) have been affected
- the medial lemniscal pathway
- the spinothalamic pathway
Side & Level of Damage: As the sensory losses (Figure 5.13)
- are limited to the lateral aspect of the left arm and extended down to include the left thumb
- involve both somatosensory pathways
- involve a dermatomal pattern
- do not involve motor function
You conclude that
- damage may involve the fifth, sixth and seventh cervical posterior roots (Figure 5.11)
- symptoms are ipsilesional (i.e., involve the left posterior roots, Figure 5.14)
Section of a Posterior Root results in the loss of all somatosensory modalities in a restricted area of the body defined by the root dermatome (Figure 5.11). Consequently, the damaged posterior root can be identified by the dermatomal pattern of sensory loss. Radiographic methods can be used to determine if the roots are being compressed by abnormalities in the vertebra.
| Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 | Example 7 | Example 8 |
