The thoracic nerves originate from the thoracic region of the spinal cord. The first two thoracic nerves also contribute fibers to the upper limb. The upper five thoracic nerves are limited to the thoracic wall, while the lower five also extend to the abdominal wall. The twelfth thoracic nerve innervates the abdominal wall and buttock skin. The oculomotor, trochlear, and abducent cranial nerves innervate different eye muscles. The oculomotor nerve innervates all eye muscles except the superior oblique and lateral rectus. The trochlear nerve innervates the superior oblique. The abducent nerve innervates the lateral rectus. The accessory nerve has

1. Thoracic Nerves
AND
Motor Cranial Nerve
student :: Zaeid .Alhamashi

2. The Thoracic Nerves :The anterior divisions of
the thoracic nerves are twelve in number on
either side. Eleven of them are situated between
the ribs, and are therefore
termed intercostal;
the 12th lies below
the last rib

3. .

4. .
•Each nerve is connected with the
adjoining ganglion of the sympathetic
trunk by a gray and a white ramus
communicans

5. • The First Thoracic Nerve -the anterior division of
the first thoracic nerve divides into two branches:
one,the larger, leaves the thorax in front of the neck
of the first rib, and enters the brachial plexus; the
other and smaller branch, the first intercostal nerve,
runs along the first intercostal space, and ends on
the front of the chest as the first anterior cutaneous
branch of the thorax.

6. .
•The first two nerves supply fibers to
the upper limb in addition to their
thoracic branches;
•The next four are limited in their
distribution to the parietes of the
thorax;

7. •The lower five supply the parietes of the
thorax and abdomen.
•The twelfth thoracic is distributed to the
abdominal wall and the skin of the
buttock.

9. .
•The Upper Thoracic Nerves
( intercostales)-The anterior divisions
of the 2nd , 3rd , 4th , 5th, and 6th
thoracic
nerves, and the small branch from the
first thoracic, are confined to the parietes of the
thorax, and are named thoracic intercostal nerves.

10. cont

11. •They pass forward in the intercostal
spaces below the intercostal vessels.
•At the back of the chest they lie
between the pleura and the posterior
intercostal membranes,

12. .
•Branches.—Numerous slender muscular
filaments supply the Intercostales, the
Subcostales, the Levatores costarum, the
Serratus posterior superior, and the
Transversus thoracis. At the front of the
thorax some of these branches cross the
costal cartilages from one intercostal space to
another

13. .
•Lateral cutaneous branches are derived from
the
intercostal nerves, about midway
between the vertebræ and sternum; and divide
into
anterior and posterior branches……

14. cont
The anterior branches run forward to the
side and the forepart of the chest,
supplying the skin,
The posterior branches run backward,
and supply the skin over the scapula
and Latissimus dorsi.

15. .
•The Lower Thoracic Nerves.
The anterior divisions of the 7th , 8th , 9th,
10th, and 11th thoracic nerves are
continued anteriorly from the intercostal
spaces into the abdominal wall; hence
they are named thoracicoabdominal
intercostal nerves.

16. .
• twelfth thoracic nerve is larger than the others; it
runs along the lower border of the twelfth rib,
often gives a communicating branch to the first
lumbar nerve, It communicates with the
iliohypogastric nerve of the lumbar plexus, and
gives a branch to the Pyramidalis. The lateral
cutaneous branch of the last thoracic nerve is
large, and does not divide into an anterior and a
posterior branch.

17. .

18. Motor Cranial Nerve

20. .
•The Oculomotory Nerve(III)
supplies somatic motor fibers to
all the ocular muscles, except the
Obliquus superior and Rectus
lateralis

21. .
The fibers of the oculomotor nerve
arise
from a nucleus which lies in the gray
substance of the floor of the cerebral
aqueduct and extends in front of the
aqueduct for a short distance into the
floor of the 3rd ventricle.

22. ,
The nucleus of the oculomotor n, does not
consist of a continuous column of cells,
but is broken up into a number of smaller
nuclei, which are arranged in two groups,
anterior and posterior. the nerve is invested with a
sheath of pia mater, and enclosed in a
prolongation from the arachnoid.

24. Oculomotory n. Enter to the orbital cavity
through Superior orbital fissure

25. .
It then divides into two branches, which
enter the orbit through the superior orbital
fissure
The superior ramus, the smaller, passes
medialward over the optic nerve, and
supplies the Rectus superior and Levator
palpebræ superioris.

26. • The inferior ramus, the
larger, divides into three branches. One
passes beneath the optic nerve to the
Rectus medialis; another, to the Rectus
inferior; the third and longest runs
forward
between the Recti inferior and lateralis to
the Obliquus inferior.

28. .
The Trochlear Nerve(IV) - the smallest of the
cranial nerves, It arises from a nucleus situated in the
floor of the cerebral aqueduct, opposite the upper part
of the inferiorcolliculus
It crosses theoculomotor nerve,
enters the orbit through the sup.
orbital fissure ,to supplies the Obliquus superior oculi

29. .
The Abducent Nerve(VI) arise from a small
nucleus situated in the upper part of the
rhomboid fossa, close to the middle line
and beneath the
colliculus
facialis

30. .It Enters the orbit cavity through
the sup.
orbital fissure and it has only one
branch to supply Rectus lateralis
m.

31. .
The Accessory Nerve(XI) consists of two parts:
a cranial and a spinal.
The Cranial Part;; is the smaller of the two. Its
fibers arise from the cells of the nucleus
ambiguus and emerge as four or five delicate
rootlets from the side of the medulla
oblongata,below the roots of the vagus. It runs
lateralward to the jugular foramen, where it
interchanges fibers with the spinal portion or
becomes united to it for a short distance;

32. .
• where it is also connected by one or two
filamentswith the jugular ganglion of the
vagus. It then passes through the jugular
foramen, separates from the spinalportion
and is continued over the surface of the
ganglion nodosum of the vagus.
Through the pharyngeal branch it probably
supplies the Musculus uvulæ and Levator
veli palatini.

33. .
•The Spinal Part ;;its fibers arise from the
motor cells of the anterior column of the
gray substance of the medulla spinalis as
low as the 5th cervical nerve. Passing
through the lateral funiculus of the medulla
spinalis, they emerge on its surface and
unite to form a single trunk,

34. .
Enters the skull through the foramen magnum,
and is then directed to the jugular foramen,
through which it passes, lying in the same
sheath of dura mater as the vagus, but separated
from it by a fold of the arachnoid.
it unites with the 2nd and 3rd cervical nerves,
while beneath the Trapezius it forms a plexus
with the 3rd and 4th cervical nerves, and from this
plexus fibers are distributed to the muscle.

36. .
The Hypoglossal Nerve (XII)
• is the motor nerve of the tongue (All tongue muscles
•except palatoglossus) across through Foramen:
Hypoglossal canal .Its fibers arise from the cells of the
hypoglossal nucleus (anterior gray substance of the
medulla spinalis) which is about 2 cm. in length, and its
upper part corresponds with the trigonum hypoglossi,
or lower portion of the medial eminence of the
rhomboid

37. .
• In the posterior triangle it unites with the
second and third cervical nerves, while beneath
the Trapezius it forms a plexus with the third
and fourth cervical nerves, and from this plexus
fibers are distributed to the muscle

38. .

39. Summry cranial nerves

40. THANK YOU FOR ATTENTION ?ANY
QUESTIONS