Which spinal dermatome corresponds to sensory disturbances such as numbness and tingling over the lateral aspect of the leg and heel?
Solution
Correct Answer: Option B
The spinal dermatome that corresponds to sensory disturbances such as numbness and tingling over the lateral aspect of the leg and heel is S1.
- Each spinal nerve root corresponds to a specific area of skin sensation called a dermatome.
- The S1 dermatome covers the posterior and lateral aspect of the leg, as well as the lateral side of the foot and the heel.
- Therefore, sensory symptoms such as numbness, tingling, or paresthesia in these regions often indicate involvement of the S1 nerve root.
- This can occur in conditions like sciatic nerve irritation or S1 radiculopathy often resulting from a herniated disc at the L5-S1 level.
In contrast:
- The L5 dermatome involves the lateral leg and dorsum of the foot, especially the great toe.
- The L4 dermatome covers the anteromedial thigh and leg, extending to the medial malleolus.
- The S2 dermatome covers the posteromedial aspect of the thigh and lower leg.
Therefore, the involvement of the lateral leg and heel specifically points to S1 sensory disturbance.
Key Points:
- S1 dermatome: lateral leg, lateral foot, heel
- Sensory disturbance in this area: suggests S1 nerve root pathology
- Conditions: Sciatic nerve irritation, S1 radiculopathy from disc herniation at L5-S1
Reference: Gray's Anatomy, Volume 1, Chapter on Spinal Nerves / Dermatome Mapping
- Each spinal nerve root corresponds to a specific area of skin sensation called a dermatome.
- The S1 dermatome covers the posterior and lateral aspect of the leg, as well as the lateral side of the foot and the heel.
- Therefore, sensory symptoms such as numbness, tingling, or paresthesia in these regions often indicate involvement of the S1 nerve root.
- This can occur in conditions like sciatic nerve irritation or S1 radiculopathy often resulting from a herniated disc at the L5-S1 level.
In contrast:
- The L5 dermatome involves the lateral leg and dorsum of the foot, especially the great toe.
- The L4 dermatome covers the anteromedial thigh and leg, extending to the medial malleolus.
- The S2 dermatome covers the posteromedial aspect of the thigh and lower leg.
Therefore, the involvement of the lateral leg and heel specifically points to S1 sensory disturbance.
Key Points:
- S1 dermatome: lateral leg, lateral foot, heel
- Sensory disturbance in this area: suggests S1 nerve root pathology
- Conditions: Sciatic nerve irritation, S1 radiculopathy from disc herniation at L5-S1
Reference: Gray's Anatomy, Volume 1, Chapter on Spinal Nerves / Dermatome Mapping
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