High-Yield Neuroanatomy 5e

Fasciculus gracilis
Fasciculus cuneatus
Posterior
spinocerebellar
tract
Lat.
corticospinal
tract
Lat.
spinothalamic
tract
Anterior
spinocerebellar
tract
Posterior
horn
Anterior
horn
Anterior white commissure
Anterior corticospinal tract
Spinal Cord 55
Ipsilateral loss of fine touch, conscious
proprioception, and vibratory sense
from lower limb
Loss of of fine touch, conscious
proprioception, and vibratory sense
from upper limb
Ipsilateral segmental anesthesia
and areflexia
Ipsilateral lower limb
dystaxia
Ipsilateral spastic
paresis with
pyramidal signs
Contralateral lower
limb dystaxia
Contralateral loss of
pain and temperature
sensation one segment
below lesion
Ipsilateral flaccid paralysis
in affected myotomes
Bilateral loss of pain and temperature
sensation within dermatomes
of involved segments
Mild contralateral muscle weakness
in proximal muscles
Figure 6-9 Transverse section of the cervical spinal cord. The clinically important ascending and descending pathways
are shown on the left. Clinical deficits that result from the interruption of these pathways are shown on the right.
II
Sensory Pathway Lesions. An example of a condition caused by these
lesions is posterior column disease (tabes dorsalis) (Figure 6-10C). This disease is seen in
patients with neurosyphilis. It is characterized by a loss of fine touch, conscious proprioception,
and vibratory sense. Irritative involvement of the posterior roots results in pain and paresthesias.
Patients have a Romberg sign. (Subject stands with feet together and, when their eyes are closed,
loses balance. This is a sign of posterior column ataxia.)
III
Combined Motor and Sensory Lesions
A. Spinal Cord Hemisection (Brown-Séquard Syndrome) (Figure 6-10E) is caused
by damage to the following structures:
1. Posterior columns (gracile [leg] and cuneate [arm] fasciculi). Damage results in ipsilateral
loss of fine touch, conscious proprioception, and vibratory sense.
2. Lateral corticospinal tract. Damage results in ipsilateral spastic paresis with pyramidal signs
inferior to the lesion.
3. Lateral spinothalamic tract. Damage results in contralateral loss of pain and temperature sensation
one to two segments inferior to the lesion.
4. Hypothalamospinal tract. Damage results in ipsilateral Horner syndrome (i.e., miosis, ptosis,
hemianhidrosis, and apparent enophthalmos).
5. Anterior horn. Damage results in ipsilateral flaccid paralysis.
B. Anterior Spinal Artery Occlusion (Figure 6-10F) causes infarction of the anterior twothirds
of the spinal cord but spares the posterior columns and horns. It results in damage to the following
structures: