- Brainstem—Part One 151
Cortico-
nuclear
tract
Cortico-
spinal
tract
Fronto-
pontine
tract
Addl.
cortico-
pontine
tracts
(Crus
cerebri)
Substantia
nigra
Red
nucleus
(mid-/upper
midbrain)
Periaqueductal
gray
Cerebral
aqueduct
Superior cerebellar peduncle
fiber decussation
(lower midbrain)
NUCLEI TRACTS
Posterior
Left
Anterior
Right
(Red
nucleus)
LL = Lateral lemniscus
ALS = Antero-
lateral system
Medial
lemniscus
AT = Ant. trigemino-
thalamic tract
AT
LL
ALS
Tegmentum
Basis
Tectum
DRAWING 9-2 Th e Midbrain — Partial