Paresthesia involving the skin over the anterior thigh most commonly corresponds to which dermatome?
Solution
Correct Answer: Option B
Paresthesia involving the skin over the anterior thigh most commonly corresponds to the L3 dermatome.
- The anterior thigh skin is primarily innervated by the L2 and L3 nerve roots, but the predominant dermatome responsible for sensation over the mid-anterior thigh is L3.
- The L2 dermatome covers more of the proximal, upper thigh region closer to the groin, while L4 mainly covers the medial leg and knee area, and S1 covers the lateral foot and posterior leg.
- Therefore, when patients report paresthesia or sensory disturbances over the anterior thigh, the lesion or irritation most likely involves the L3 nerve root.
- L2 dermatome: upper, proximal thigh (inguinal area).
- L3 dermatome: anterior thigh (middle to lower anterior thigh).
- L4 dermatome: medial leg and knee area.
- S1 dermatome: lateral foot and posterior leg.
This knowledge is important for clinical localization of radiculopathies or nerve injuries.
Reference: DeLisa’s Physical Medicine and Rehabilitation: Principles and Practice, Volume 1, Chapter on Neurological Examination, Page 234
- The anterior thigh skin is primarily innervated by the L2 and L3 nerve roots, but the predominant dermatome responsible for sensation over the mid-anterior thigh is L3.
- The L2 dermatome covers more of the proximal, upper thigh region closer to the groin, while L4 mainly covers the medial leg and knee area, and S1 covers the lateral foot and posterior leg.
- Therefore, when patients report paresthesia or sensory disturbances over the anterior thigh, the lesion or irritation most likely involves the L3 nerve root.
- L2 dermatome: upper, proximal thigh (inguinal area).
- L3 dermatome: anterior thigh (middle to lower anterior thigh).
- L4 dermatome: medial leg and knee area.
- S1 dermatome: lateral foot and posterior leg.
This knowledge is important for clinical localization of radiculopathies or nerve injuries.
Reference: DeLisa’s Physical Medicine and Rehabilitation: Principles and Practice, Volume 1, Chapter on Neurological Examination, Page 234
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