This document provides information about the pons including its gross appearance, internal structure, nuclei of cranial nerves V and VII, and lesions that can occur. It contains diagrams of the pons showing fiber tracts and nuclei. Statements are provided to test knowledge about the pons' anatomy and relationships.

2. PONS – CN V, VII
DR TATHEER ZAHRA
ASSISTANT PROFESSOR ANATOMY

3. GROSS APPEARANCE

4. ANTERIOR VIEW

7. POSTERIOR VIEW

10. INTERNAL STRUCTURE

11. SCHEMATIC DIAGRAM OF THE PONS SHOWING
ITS MAJOR DIVISIONS INTO TEGMENTUM AND
BASIS PONTIS, AND TYPES OF FIBER BUNDLES
TRAVERSING THE BASIS PONTIS.

12. SCHEMATIC DIAGRAM OF THE PONS
SHOWING THE MAJOR TRACTS
TRAVERSING THE TEGMENTUM

13. LEVELS OF STUDY

14. T.S. THROUGH THE CAUDAL PART
(FACIAL COLLICULUS)

16. T.S. THROUGH THE CRANIAL PART
(TRIGEMINAL NUCLEI)

18. NUCLEI OF CRANIAL NERVES
IN PONS

19. TRIGEMINAL NERVE

22. COMPOSITE SCHEMATIC DIAGRAM OF THE
AFFERENT AND EFFERENT ROOTS OF THE
TRIGEMINAL NERVE (CRANIAL NERVE V) AND
THEIR NUCLEI

28. CORNEAL REFLEX

29. TRIGEMINAL NEURALGIA

30. FACIAL NERVE

32. DISTRIBUTION

33. SCHEMATIC DIAGRAM SHOWING THE NUCLEI
OF ORIGIN, COURSE, AND AREAS OF SUPPLY
OF THE FACIAL NERVE (CRANIAL NERVE VII)

36. SCHEMATIC DIAGRAM SHOWING LESIONS IN
THE FACIAL NERVE AT DIFFERENT SITES AND
THE RESULTING CLINICAL MANIFESTATIONS
OF EACH

37. UMN LESION LMN LESION

38. LMN LESION
(BELL PALSY)

39. TUMORS OF THE PONS
ASTROCYTOMA

40. PONTINE HEMORRHAGE/
INFARCTION

41. Site of a lesion in the basal pons involving
corticospinal and other descending motor fibers and
fibers of the abducent nerve. This lesion results in
“RAYMOND'S SYNDROME”. This lesion spares the
abducent nucleus and the nucleus and axons of the
facial nerve.

42. Site of a lesion in the caudal part of the pons
involving descending motor fibers and the axons and
nucleus of the facial nerve but sparing the nucleus
and axons of the abducent nerve. This lesion results
in the “MILLARD-GÜBLER SYNDROME”.

43. Site of a lesion causing “FOVILLE'S SYNDROME”.
Involvement of the abducent nucleus causes paralysis of
the contralateral medial rectus in addition to the
ipsilateral lateral rectus muscle. The motor nucleus and
axons of the facial nerve are also destroyed, and the lesion
extends ventrally to cause partial damage to corticospinal
and other descending motor tracts.

45. 1. The following statements concern the pons:
(a) It is related superiorly to the dorsum sellae of
the sphenoid bone.
(b) It lies in the middle cranial fossa.
(c) Glial tumors of the pons are rare.
(d) The corticopontine fibers terminate in the
pontine nuclei.
(e) The pons receives its blood supply from the
internal carotid artery.

46. 2. The following statements concern the pons:
(a) The trigeminal nerve emerges on the lateral aspect
of the pons.
(b) The glossopharyngeal nerve emerges on the
anterior aspect of the brainstem in the groove
between the pons and the medulla oblongata.
(c) The basilar artery lies in a centrally placed groove
on the anterior aspect of the pons.
(d) Many nerve fibers present on the posterior aspect
of the pons converge laterally to form the middle
cerebellar peduncle.
(e) The pons forms the lower half of the floor of the
fourth ventricle.

47. 3. The following statements concern the posterior
surface of the pons:
(a) Lateral to the median sulcus is an elongated
swelling called the lateral eminence.
(b) The facial colliculus is produced by the root of the
facial nerve winding around the nucleus of the
abducent nerve.
(c) The floor of the inferior part of the sulcus limitans
is pigmented and is called the substantia ferruginea.
(d) The vestibular area lies medial to the sulcus
limitans.
(e) The cerebellum lies anterior to the pons.

48. 4. The following statements concern a transverse
section through the caudal part of the pons:
(a) The pontine nuclei lie between the transverse
pontine fibers.
(b) The vestibular nuclei lie medial to the abducent
nucleus.
(c) The trapezoid body is made up of fibers derived
from the facial nerve nuclei.
(d) The tegmentum is the part of the pons lying
anterior to the trapezoid body.
(e) The medial longitudinal fasciculus lies above the
floor of the fourth ventricle on either side of the
midline.

49. 5. The following statements concern a transverse
section through the cranial part of the pons:
(a) The motor nucleus of the trigeminal nerve lies
lateral to the main sensory nucleus in the
tegmentum.
(b) The medial lemniscus has rotated so that its long
axis lies vertically.
(c) Bundles of corticospinal fibers lie among the
transverse pontine fibers.
(d) The medial longitudinal fasciculus joins the
thalamus to the spinal nucleus of the trigeminal N.
(e) The motor root of the trigeminal nerve is much
larger than the sensory root.