Anatomy of the Vessels and Nerves of the Head and Neck (Angioneurotomy) - Chornokulskyi S.T. 2009

Nerves of the Head and Neck
Cranial Nerves

(nervi craniales) Fig. 27–50.

C. Galen (131–201 AD) was the first to divide human peripheral nerves into cranial and spinal, but METABOLISM/2.html">THE CONCEPT OF 12 pairs of Cranial nerves was introduced by anatomists in the late 17th century (Sömmerring, Vicq d'Azyr, and others).

✵ Modern anatomical nomenclature recognizes 13 pairs of cranial nerves:

✵ Terminal nerve [0] nervus terminalis [0];

✵ Olfactory nerve [I] nervus olfactorius [I];

✵ Optic nerve [II] nervus opticus [II];

✵ Oculomotor nerve [III] nervus oculomotorius [III];

✵ Trochlear nerve [IV] nervus trochlearis [IV];

✵ Trigeminal nerve [V] nervus trigeminus [V];

✵ Abducens nerve [VI] nervus abducens [VI];

✵ Facial Nerve [VII] nervus facialis [VII];

✵ Vestibulocochlear nerve [VIII] nervus vestibulocochlearis [VIII];

✵ Glossopharyngeal nerve [IX] nervus glossopharyngeus [IX];

✵ Vagus nerve [X] nervus vagus [X];

✵ Accessory nerve [XI] nervus accessorius [XI];

✵ Hypoglossal nerve [XII] nervus hypoglossus [XII];

The VII pair of cranial nerves comprises two nerves: the facial nerve (nervus facialis) and the intermediate nerve (nervus intermedius), while the VIII pair comprises the vestibular nerve (nervus vestibularis) and the cochlear nerve (nervus cochlearis).

Almost all cranial nerves or their roots (except for the olfactory nerve) emerge within the ventral surface of the Brainstem (Fig. 27). Their exit from the Skull is illustrated in Figs. 28 and 28a.

Classification of cranial nerves by development (Fig. 29).

✵ Nerves derived from the Brain — pairs I and II (nn. olfactorius et opticus);

✵ Nerves developing in association with derivatives of the HEAD (pre-otic) myotomes — pairs III, IV, VI (nn. oculomotorius, trochlearis, abducens);

✵ Nerves derived from the pharyngeal (branchial) arches:

1st pharyngeal arch — pair V (n. trigeminus);

II pharyngeal arch — pair VII (n. facialis, from which the vestibulocochlear nerve, n. vestibulocochlearis, segregated during embryonic development);

III pharyngeal arch — pair IX (n. glossopharyngeus);

IVth and Vth branchial arches — X pair (n. vagus) and the embryologically segregated XI pair (n. accessorius);

* Modern International Anatomical Terminology (São Paulo, 1997), Ukrainian standard (Kyiv, 2001).

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Fig. 27. Roots of the cranial nerves within the brainstem border, anterior view

1 - optic chiasm (chiasma opticum);

2 - optic nerve (nervus opticus II) (within the Diencephalon);

3 - tuber cinereum (tuber cinereum);

4 - mamillary bodies (corpora mamillaria);

5 - optic tract (tractus opticus);

6 - cerebral peduncle (pedunculus cerebri):

7 - oculomotor nerve (nervus oculomotorius, III);

8 - trochlear nerve (nervus trochlearis, IV);

9 - trigeminal nerve (nervus trigeminus, V);

10 - abducens nerve (nervus abducens, VI);

11 - facial and intermediate nerves (nn. facialis et intermedius, VII);

12 - vestibulocochlear nerve (nervus vestibulocochlearis, VIII);

13 - glossopharyngeal nerve (nervus glossopharyngeus, IX);

14 - vagus nerve (nervus vagus, X);

15 - accessory nerve (nervus accessorius, XI);

16 - hypoglossal nerve (nervus hypoglossus, XII);

17 - anterior median fissure (fissura mediana anterior);

18 - anterolateral sulcus (sulcus anterolateralis);

19 - decussation of pyramids (decussatio pyramidum);

20 - posterolateral sulcus (sulcus posterolateralis);

21 - olive (oliva);

22 - basilar sulcus (sulcus basilaris);

23 - anterior part (base) of the Pons (pars anterior (basilaris) pontis);

24 - posterior perforated substance (substantia perforata posterior)

✵ Nerve of the postbranchial myotome derivatives — the XII cranial nerve (n. hypoglossus) (according to another view, this is a nerve that developed through the fusion of Spinal Nerves).

Functionally, cranial nerves are divided into:

— viscerosensory (sensory) (cranial nerves 0, I);

— somatosensory (sensory) (cranial nerves II and VIII);

— somatomotor (motor) (cranial nerves III, IV, VI, XI, XII);

— mixed (cranial nerves V, VII, IX, X).

Fig. 28. Sites of exit (entry) of the cranial nerves from (into) the cranial cavity:

1 - lamina cribrosa (cranial nerve I — n. olfactorius);

2 - optic canal (canalis opticus) (cranial nerve II - n. opticus);

3 - superior orbital fissure (fissura orbitalis superior) (cranial nerves III, IV, VI — n. oculomotorius, n. trochlearis, n. abducens, and n. ophthalmicus of V-1);

4 - foramen rotundum (n. maxillaris of V^-2);

5 - foramen ovale (n. mandibularis of V^-3);

6 - internal acoustic meatus (porus acusticus internus) (cranial nerves VII, VIII, nn. facialis et vestibulocochlearis):

7 - jugular foramen (foramen jugulare) (cranial nerves IX, X, XI — vagus group of nerves: nn. glossopharyngeus, vagus, accessorius — radix cranialis);

8 - canal of the hypoglossal nerve (canalis n. hypoglossi) (cranial nerve XII, n. hypoglossus);

9 - foramen magnum (XI — radix spinalis n. accessorii) - entrance to the cranial cavity

Study outline for the cranial nerves

1. Name (Ukrainian, Latin), Water/144.html">Origin of the nerve.

2. Nuclei, localization, and characteristics.

3. Presence of somatic ganglia.

4. Fiber COMPOSITION OF THE ROOT.

5. Fiber composition of the nerve trunk.

6. Classification of nerve branches, autonomic ganglia.

7. Ramification of each branch, topography.

8. Area of innervation of each branch and the nerve as a whole.

Fig. 28 a. Topography of the cranial nerves and their roots on the internal Base of the skull

Terminal nerve [0] [n. terminalis)

In the anteroinferior PARTS OF THE cartilaginous nasal septum, posterior and superior to the incisive canal, there is an opening leading into a blind canal — a vestigial Olfactory Organ — the vomeronasal organ (of Jacobson), organum vomeronasale (Jakobson).

In many animals, it is well developed. The stimulus for the receptors (neurosensory epitheliocytes) of this organ consists exclusively of pheromones. The clusters of neurosensory epitheliocyte Cell bodies form the terminal ganglion (ganglion terminale). The axons of the ganglion epitheliocytes join the olfactory filaments of the n. olfactorius and reach the structures of the limbic system as a part of it. The Pathways of the terminal nerve have not been thoroughly studied, but it is believed that this nerve plays a certain psychological role in human relationships.

Fig. 29. A — Cranial NERVES OF THE pharyngeal arch derivatives (pairs V, VII, IX, X, XI) 1, 2, 3, 4, 5 — pharyngeal arches of the human embryo; B — General diagram of the innervation of Muscles derived from preauricular, occipital myotomes, and pharyngeal arches