Pressure Sense is Carried by the Dorsal Column Medial Lemniscus Pathway
Pressure sense is primarily carried by the dorsal column medial lemniscus (DCML) pathway, which includes the fasciculus gracilis and fasciculus cuneatus tracts. 1
Anatomy and Function of the Dorsal Column Pathway
The dorsal column tracts are responsible for transmitting several discriminative sensory modalities:
- Pressure sensation
- Fine touch
- Vibration
- Proprioception (joint position sense)
- Two-point discrimination 1, 2
Anatomical Organization
The dorsal column pathway is organized as follows:
- Fasciculus gracilis: Carries sensory information from the lower limbs and lower trunk
- Fasciculus cuneatus: Carries sensory information from the upper limbs and upper trunk 2
Neuronal Contributions
The dorsal column tracts receive fiber contributions from specific laminae of the spinal cord:
- Cervical level (C1-C4): Primarily from lamina V and some from lamina III
- Lower cervical level (C5-C8): From laminae III, V, and Clarke's dorsal nucleus
- Upper thoracic level (T1-T4): From lamina V and Clarke's dorsal nucleus
- Lower thoracic (T5-T12) and lumbar levels (L1-L5): Exclusively from Clarke's dorsal nucleus 3
Clinical Significance
Damage to the dorsal column pathway results in specific sensory deficits:
- Loss of pressure sensation
- Impaired vibration sense
- Diminished proprioception
- Reduced two-point discrimination
- Positive Romberg test 1, 4
Ipsilateral Sensory Loss
An important clinical feature of dorsal column lesions is that sensory deficits occur on the same side (ipsilateral) as the lesion. This contrasts with spinothalamic tract lesions, which cause contralateral sensory deficits for pain and temperature 2.
Clinical Evidence
Studies of patients with spinal cord lesions confirm that pressure and position sense travel in the dorsal columns rather than alternative pathways:
- Patients with interrupted dorsal columns but intact dorsal spinocerebellar tracts show loss of position sense, vibration sense, and tactile discrimination
- Conversely, patients with damaged dorsal spinocerebellar tracts but partially intact dorsal columns maintain position and vibration sense 5
Relationship to Neuropathic Pain
Research indicates that impaired dorsal column function may contribute to neuropathic pain development after spinal cord injury:
- Patients with spinal cord injury and neuropathic pain show significantly greater impairment of dorsal column-mediated function compared to those without pain
- This suggests that both spinothalamic tract and dorsal column pathway dysfunction may be necessary for the development of neuropathic pain after spinal cord injury 4
Clinical Testing
To assess pressure sensation clinically:
- Apply pressure stimulus to the skin using fingertip or blunt instrument
- Test symmetrically on both sides of the body
- Compare responses at different levels to identify sensory level if a lesion is present
- Document any areas of diminished or absent pressure sensation 1
In summary, pressure sensation is transmitted via the dorsal column medial lemniscus pathway, which ascends ipsilaterally in the spinal cord and includes the fasciculus gracilis and fasciculus cuneatus tracts.