From the Research
The dermatome for the 4th toe is primarily L5 (fifth lumbar spinal nerve). The L5 dermatome supplies sensory innervation to the lateral aspect of the lower leg, the top of the foot, and extends to the 4th toe. This means that damage or compression of the L5 nerve root may result in sensory changes, such as numbness, tingling, or pain in the 4th toe. It's essential to note that there can be some overlap between adjacent dermatomes, so the S1 (first sacral) dermatome may also contribute some sensory innervation to this area.
When assessing for potential nerve root compression or neurological disorders affecting the lower extremities, testing sensation in the 4th toe can help identify L5 nerve root involvement. This knowledge is clinically relevant when evaluating patients with back pain, sciatica, or other neurological complaints affecting the lower limbs. According to the most recent study 1, the distribution of pain and pins and needles did not correspond well with dermatomal patterns, highlighting the complexity of dermatomal mapping. However, the L5 dermatome is still considered the primary dermatome for the 4th toe, as supported by earlier studies 2 that constructed an evidence-based dermatome map.
Some key points to consider when evaluating dermatomes include:
- The overlap between adjacent dermatomes, which can lead to variability in sensory innervation 3
- The individual subject variation in dermatomal patterns, which can make diagnosis challenging 1
- The importance of considering multiple factors, including patient history, physical examination, and diagnostic tests, when evaluating nerve root compression or neurological disorders 4
In clinical practice, understanding the dermatomal distribution of sensory innervation can help guide diagnosis and treatment of neurological disorders affecting the lower extremities. The L5 dermatome is the primary dermatome for the 4th toe, and testing sensation in this area can provide valuable information for clinicians evaluating patients with back pain, sciatica, or other neurological complaints.