The pons is located in the brainstem, between the midbrain and medulla oblongata. It contains fibers that connect the cerebellum and cerebrum, and nuclei for several cranial nerves including the trigeminal, facial, and abducent nerves. The pons receives its blood supply primarily from the basilar artery and its branches, as well as the anterior inferior cerebellar and superior cerebellar arteries. It plays an important role in motor functions and sensory processes.

1. Pons
By
Dr. Noura El Tahawy
drnosman@yahoo.com
http://www.slideshare.net/drnosman

2. Ventral view of
the brainstem in
situ.

3. Principal subdivisions and some important landmarks in the mature brain.
(B) ventral aspect. Cranial nerves are indicated in yellow.

4. A, Sagittal hemisection of the brain to show the third and fourth ventricles. Pia mater:
red; ependyma: blue. B, Sagittal hemisection through the brain.

5. Position of pons
Midsagittal section of the skull

6. Sagittal hemisection of the brain

7. Median sagittal section through the head and neck.

8. Sagittal MRI 'slice' of the living brain.

9. MRI scan of head in sagittal plane.

10. Horizontal section through the cerebellum and brain stem.

11. Ventral aspect
of the brain
stem.

13. (A) Anterior view of the brainstem.

14. The dorsal aspect of the brain stem. The floor of the fourth ventricle has been
exposed by cutting the cerebellar peduncles and removing the cerebellum.

15. (B) Posterior view of the brainstem.

16. (B) Posterior view of
the brainstem.

17. The cranial nerve nuclei.

18. Transverse section through the brain stem at the level of the pontine-
mesencephalic junction.

19. Transverse section through the rostral pons.

20. Transverse section through the mid-pons at the level of the trigeminal
nerve.

21. Transverse section through the caudal pons.

22. Transverse section of the pons at level of facial
colliculus (Caudal pons)
Tegmentum of
pons directed
upward
continuation of
medulla oblongata
Basilar part
contain both
longitudinal and
transverse fibers
intermixed with
pontine nuclei

23. Types of fibers in the basis pontis
Longitudinal Descending
Corticospinal
Corticobulbar
Corticopontine
Transverse fibers:
Pontocerebellar
Cerebellopontine

24. Tegmentum (Dorsal part) of the pons
By
Dr. Noura El Tahawy

25. Ascending tracts
Medial lemniscus
Spinal lemniscus
Trigeminal lemniscus
Lateral lemniscus
Medial longitudinal bundle

26. Transverse section of the pons at the level of facial colliculus
Medial long. fasciculus
Facial colliculus
Superior medullary velum
Cavity of 4 th ventricle
Superior cerebellar peduncle
Vestibular nuclei Nucleus of abducent n.
Inferior cerebellar peduncle Motor nucleus of
facial n.
Spinal nucleus and tract
of trigeminal nerve
MCP
Lateral lemniscus
Transverse pontine fibers Reticular
formation
Facial nerve
Abducent nerve Dicussation of
Long. Fibers in basis pontis Trapezoid body

27. Transverse section of the pons
The central course of the fibres of the facial nerve in a transverse section of the pons, viewed
from the rostral aspect.

28. Cranial nerve nuclei in the Pons
Special visceral motor nuclei
Nucleus Site Cranial n. Function
Motor nucleus of Pons V Masticatory muscles
trigeminal n.
Motor nucleus of Pons V Facial muscles,
facial n. platysma, posterior belly
of digastric, stylohyoid,
stapedius muscles

29. Cranial nerve nuclei in the Pons
General somatic motor nuclei
Nucleus Site Cranial n. Function
Nucleus of Pons VI Lateral rectus
abducent n.
General visceral motor nuclei
Nucleus Site Cranial Function
n.
Superior salivatory Pons VII Submandibular,
nucleus sublingual and lacrimal
glands

30. Cranial nerve nuclei in the Pons
General somatic sensory nuclei
Nucleus Site Cranial n. Function
Mesencephalic Midbrain V Proprioception
nucleus of (in rostral of head
trigeminal n. Pons)
Main sensory Pons V Tactile
nucleus of sensation of
trigeminal head
Spinal nucleus of Medulla V Pain &
trigeminal (in caudal Temperature of
Pons) head

31. Cranial nerve nuclei in the Pons
Special somatic sensory nuclei
Nucleus Site Cranial Function
n.
Cochlear Pons and VIII Sense of hearing
nuclei medulla
(dorsal &ventral)
Vestibular Pons and VIII Sense of
nuclei medulla equilibrium
(Superior, medial,
lateral, inferior)

32. Non-cranial nerve nuclei in pons
Nucleus Site
Superior olivary nucleus Tegmentum of Pons
Pontine nuclei Basilar pons

33. Blood Supply of the Pons

34. The subclavian arteries and their branches.

36. Arteries on the base of the brain injected with resin.

37. Vertebro-basilar system
The two vertebral arteries arise from the
subclavian arteries and ascend the neck in
the foramina transversaria of the upper six
cervical vertebrae. They enter the skull
through the foramen magnum and unite at
the lower border of the pons to form the
basilar artery .The basilar artery ascends to
the upper border of the pons and divides into
two posterior cerebral arteries

38. The circulus arteriosus on the base of the brain

39. About a dozen pontine arteries (from basilar
artery) supply the full thickness of the medial
part of the pons
The anterior inferior cerebellar and
superior cerebellar arteries (both arise from
basilar artery) supply the side of the pons
before giving branches to the cerebellum .

40. The arteries on the base of the brain.

41. Thanks
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