Brainstem Cross Section IDs

Question 1

Level?

Answer 1

Level = Rostral Midbrain

A: cerebral peduncle

B: spinothalamic tract (or anterolateral tract – contra. body pain and temp.) and medial lemniscus (contra. body touch, pressure, 2-point)

C: cerebral aqueduct

D: periaqueductal gray

E: Superior colliculus

F: Oculomotor complex – contains somatic motor oculomotor nucleus and pregang. parasympathetic Edinger-Westphal nucleus

G: Red nucleus

H: arrow points to rootlets of oculomotor nerve.

Question 2

Level?

Answer 2

Caudal Midbrain

A: cerebral peduncle

B: spinothalamic tract (or anterolateral tract – contra. body pain and temp.) and medial lemniscus (contra. body touch, pressure, 2-point etc.)

C: cerebral aqueduct

D: medial longitudinal fasciculus

E: periaqueductal gray

F: Inferior colliculus

G: Superior cerebellar peduncle

Question 3

Level?

Answer 3

Middle Pons

A: descending cortical axons of layer 5 pyramidal cells – some are destined for brainstem nuclei, some spinal cord

B: Sensory Nucleus V (or Chief Sensory V)

C: spinothalamic tract (or anterolateral tract, contra. body pain/temp.) and medial lemniscus (contra. body touch, pressure 2-point)

D “D” is in the 4th ventricle – the arrow points to the medial longitudinal fasciculus.

E: Motor nucleus of V

F: Pontine gray

G: Middle cerebellar peduncle

H: Trigeminal nerve (cranial nerve V).

Question 4

Level?

Answer 4

Caudal Pons

A: descending cortical axons of layer 5 pyramidals

B: spinal nucleus V, bordered laterally by spinal tract of V

C: spinothalamic tract (or anterolateral tract, contra body pain/temp.) and medial lemniscus (contra. body touch, pressure, 2-point)

D “D” is in the 4th ventricle – the arrow points to the medial longitudinal fasciculus

E: Abducens nucleus (VI)

F: Facial nucleus (motor nucleus of cranial nerve VII)

G: Pontine gray

H: Middle cerebellar peduncle

Question 5

Level?

Answer 5

Rostal (Open) Medulla

A: Pyramid – corticospinal axons that have not crossed yet

B: spinal nucleus V, bordered laterally by spinal tract of V.

C: Dorsal spinocerebellar tract about here – it is starting to enter the inferior cerebellar peduncle.

D: spinothalamic tract (or anterolateral tract) about here

E: medial lemniscus

F: “F” is in the 4th ventricle – the arrow points to the medial longitudinal fasciculus

G: Hypoglossal nucleus

H: Dorsal motor nucleus of the Vagus

I: Solitary tract and nucleus (taste at this level)

J: Nucleus ambiguus about here

K: Inferior olive

Question 6

Level?

Answer 6

Caudal (closed) Medulla

A: Pyramid

B: funiculus (dark axons) and nucleus (lighter cell bodies) gracilus

C: funiculus (dark axons) and nucleus (lighter cell bodies, very small here) cuneatus

D: spinal nucleus V, bordered laterally by spinal tract of V

E: dorsal spinocerebellar tract about here

F: spinothalamic tract (or anterolateral tract) about here

G: medial lemniscus

Question 7

Level?

Answer 7

Spinomedullary Junction

A: Pyramid

B: lateral cortical spinal tract. Crossed axons of layer 5 pyramidals mostly controlling fine motor movements of extremities

C: funiculus (dark axons) and nucleus (lighter cell bodies) gracilus
D: funiculus (dark axons) and nucleus (lighter cell bodies, very few here) cuneatus
E: spinal nucleus V, bordered laterally by spinal tract of V.

F: dorsal spinocerebellar tract about here

G: spinothalamic tract (or anterolateral tract) about here.