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Applied Anatomy II: Mandibular Arch
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44
Open/Closed Mouth and Pterygomandibular Space
In a closed mouth the medial (internal) pterygoid and
temporal muscles are relaxed and the pterygomandibular
space is a very narrow groove. In a wide open mouth the
coronoid process moves forward and downward, and the
medial (internal) pterygoid and temporal muscles contract, elongating the pterygomandibular raphe or ligament. Under these circumstances the pterygomandibular
space grows, adopting a triangular shape and filling up
with areolar and adipose tissue transferred under pressure from the maxillary tuberosity and adjacent regions
(Angelman1945).
Contents ofthe Pterygomandibular Space
This space, with a volume of around 2 ml with an open
mouth (Murphy and Grundy1969; Takeuchi 1993), is a
groove about 3–4
mm wide in its anterior (entrance) side
mm long in the anterior–posterior direction (Murphy and Grundy 1969). It contains primarily
lax, adipose connective tissue (Sicher1946; Bremer1952;
Via1953; Murphy and Grundy1969) suspended from the
planes of several fascias (Galbreath and Eklund 1970)
(Figure3.14). By region (high, medium, and low), its content is as follows.
● High/cranial region. Here, nearly in the infratemporal
fossa (zygomatic fossa), the contents include the following (Berns and Sadove1962; Galbreath and Eklund 1970;
Shaw and Fierst1988; Pretterklieber etal.1991).
○ Arteries: They are robust in this region and are not in
a restricted space but move very freely (Watson1973;
Coleman and Smith 1982). The arteries present
include the maxillary artery (internal maxillary
artery), a branch of the external carotid artery and its
descending loop where present (Lacouture etal.1983),
the accessory meningeal artery, and behind it the middle meningeal artery.
○ The veins constitute the most inferior branches of the
pterygoid venous plexus (Via 1953; Archer and
Zubrow1954).
○ The nerves present include the lingual nerve, attached
to the chorda tympani (branch of the facial nerve, CN
VII), the buccal nerve that passes between the two bellies/fascicles/heads of the lateral (external) pterygoid
muscle (Figure3.13), and the auriculotemporal nerve.
● Central/middle region. From front to back this region
houses the following (Barker and Davies1972) (Figure3.14).
○ The lingual artery and vein, located in front on the
lingual nerve (Harn and Durham 2003), separate
from the alveolar artery and vein around 5–15 mm
before entering the mandibular foramen (Archer and
Zubrow1954).
○ The lingual nerve lies around 7–10 mm from the
entrance to the pterygomandibular space along the anterior (ventral) part of the pterygotemporal depression
(Murphy and Grundy1969; Barker and Davies1972).
○ The inferior alveolar nerve also lies in this cen-
tral region.
○ In 10% of cases the inferior alveolar artery may lie for-
ward of the inferior alveolar nerve, but it is always
much closer to the bone (Roda and Blanton 1994;
Khoury etal.2011).
○ The veins associated with the inferior alveolar nerve
(one to four veins) are tributaries of the pterygoid
venous plexus (Archer and Zubrow 1954; Khoury
etal.2010).
● Lower region. This region houses:
○ The inferior alveolar nerve before it enters the man-
dibular foramen.
○ The mylohyoid nerve after its separation from the infe-
rior alveolar nerve around 15
mm before the latter
enters the mandibular foramen (Wilson etal. 1984;
Bennett and Townsend2001).
○ The mylohyoid artery and vein, behind the mylohyoid
nerve (Archer and Zubrow1954).
○ The lingual artery and vein that separate from the
associated veins around 5–15
mm before the inferior
alveolar artery enters the mandibular foramen (Archer
and Zubrow1954).
Sphenomandibular Ligament
The sphenomandibular ligament is located mainly in the
central (middle) and lower region of the pterygomandibular space. It is a fibrous band that originates in the spine
of the sphenoid bone and the petrotympanic fissure
(upper attachment), and runs into the posterior border
and medial aspect of the lingula of the mandible (lower
attachment) (Barker and Davies 1972; Garg and
Townsend2001; Shiozaki etal.2007; Khoury etal.2011)
(Figure3.14). The shape, size, and nature of its attachments vary significantly from one person to another
(Garg and Townsend2001; Shiozaki etal.2007; Khoury
etal. 2010). The interpterygoid fascia covers the entire
medial aspect of the mandibular ramus and sphenomandibular ligament (Garg and Townsend 2001). The ligament may even be considered a thickening of the
interpterygoid fascia (Barker and Davies1972; Khoury
etal.2011; Lipski etal.2013).
It is interesting note that the mylohyoid nerve emerges
from behind the postero- inferior mandibular attachment
of the sphenomandibular ligament before inserting in the
t.me/Dr_Mouayyad_AlbtousH
mylohyoid groove (Barker and Davies 1972; Garg and
17 mm
(b)
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Townsend2001).
Given its density and shape, the sphenomandibular ligament has the potential to impede diffusion of local anesthetic solution to the inferior alveolar nerve (Barker and
Davies1972; Garg and Townsend2001; Shiozaki etal.2007;
Khoury etal.2010,2011), especially if the tip of the needle
is placed too far medially or inferiorly with respect to the
ligament (Khoury etal.2010,2011).
Positive Aspirations andHematomas
In the highly vascularized pterygomandibular space, the
likelihood of piercing a vessel during the mandibular block
procedure is high, inducing positive aspiration or hemorrhage (especially where an artery is involved) due to intravascular injection (Roda and Blanton 1994). The vessels
that may be impacted, depending on where the needle is
inserted, are as follows.
● Injection too high
○ The lowest branches of the pterygoid venous plexus
may be pierced (Archer and Zubrow1954; Roda and
Blanton1994).
○ The maxillary artery (internal maxillary artery) or its
descending loop: in 60% of cases this artery runs very
superficially and laterally relative to the lateral (external) pterygoid muscle (Pretterklieber et al. 1991)
(Figure 3.13). Under these circumstances, in around
90% of cases (possibly equivalent to 50% of patients), a
descending loop lies close to the mandibular foramen
(Lacouture etal.1983) (Figure3.15) and may be pierced.
Moreover, the diameter of the loop at this point varies
substantially, from 2 to 6 mm (Biermann1943).
○ The inferior alveolar artery and vein may be pierced
where they course near the condyle (Archer and
Zubrow1954).
○ The intramuscular vessels of the lateral (external)
pterygoid muscle are vulnerable.
● Even when the needle is introduced at a suitable height,
it may pierce the artery and veins that accompany the
inferior alveolar nerve. Given that these vessels normally
lie closer to the bone than to the nerve and the artery is
forward of the nerve in only 10% of cases, it is not readily
pierced (Roda and Blanton 1994; Khoury etal. 2011).
However, as the veins are located further back, they are
more easily injected (Khoury etal. 2010). The same is
true of the lingual artery, which lies in front of the lingual nerve and is therefore the first artery encountered as
the needle enters the pterygomandibular space (Harn
and Durham2003).
Pterygomandibular Space 45
(a)
9 mm
Figure3.15 Maxillary artery and its descending loop, where
present: (a) most frequent location of descending loop;
(b)another configuration with descending loop.
● Injection too low
○ The mylohyoid artery and vein are vulnerable,
although it would take a deep injection to pierce them
(Archer and Zubrow1954).
○ The lingual artery and vein are vulnerable.
○ The medial (internal) pterygoid muscle intramuscular
vessels are vulnerable.
● An overly medial (internal) injection, even inside the
pterygomandibular raphe or ligament, may pierce the
intramuscular vessels of the medial (internal) pterygoid muscle.
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Applied Anatomy II: Mandibular Arch
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46
Glossary
Anatomical terminology Other terminology used
Otic ganglion
Submandibular node
Auriculotemporal nerve Superficial temporal nerve
Buccal nerve Buccinator nerve
Inferior alveolar nerve Inferior dental nerve
Mandibular nerve Inferior maxillary nerve
Meningeal branch or nervus
spinosus
Angle of mandible Gonial angle
Coronoid process Coronoid apophysis
External acoustic meatus Acoustic meatus
Infratemporal fossa Zygomatic fossa
Lingula Spix spine
Arnold’s ganglion
Submaxillary ganglion/node
Long buccal nerve
Recurrent meningeal nerve
Recurrent meningeal branch
of spinal nerves
References
Anatomical terminology Other terminology used
Mandibular canal Inferior dental canal
Mandibular notch Sigmoid notch
Mylohyoid line Internal oblique line
Mylohyoid crest
Oblique line External oblique line
Pterygomandibular space Pterygomaxillary space
Retromolar trigone Retromolar triangle
Lateral pterygoid muscle External pterygoid muscle
Levator veli palatini Internal peristaphylin muscle
Malleus muscle Tensor tympani muscle
Medial pterygoid muscle Internal pterygoid muscle
Tensor veli palatine External peristaphylin muscle
Maxillary artery Internal maxillary artery
Buccal Vestibule
Premolars Bicuspids
Allen, G.D. (1979). Dental Anesthesia and Analgesia (Local
and General), 2e. Baltimore: Williams and Wilkins. 83.
Andreasen, J.O., Petersen, J.K., and Laskin, D.M. (1997).
Textbook and Color Atlas of Tooth Impactations. Diagnosis,
Treatment and Prevention. Copenhagen: Munksgaard. 266.
Annex 3. Lingual nerve and inferior alveolar nerve.
Annex 4. Mandibular incisive canal and anterior loop.
Annex 5. Mental foramen.
Angelman, J. (1945). The inferior dental injection. Br. Dent.
J. 79 (2): 31–37.
Apostolakis, D. and Brown, J.E. (2013). The dimensions of
the mandibular incisive canal and its spatial relationship to
various anatomical landmarks of the mandible: a study
cone beam computed tomography. Int. J. Oral Maxillofac.
Implants 28 (1): 117–124.
Archer, W.H. and Zubrow, H.J. (1954). Fatal hemorrhage
following regional anesthesia for operative dentistry in a
hemophiliac. Oral Surg. Oral Med. Oral Pathol. 7 (5):
464–470.
Arens, D.E., Adams, W.R., and De Castro, R.A. (1984).
Cirugía en endodoncia. Barcelona: Ed Doyma. 38–50.
Arensburgh, B. and Nathan, H. (1979). Anatomical
observation on the mylohyoid groove, and the course of the
mylohyoid nerve and vessels. J. Oral Surg. 37 (2): 93–96.
Ashkenazi, M., Taubman, L., and Gavish, A. (2011). Age-
associated changes of the mandibular foramen position in
anteroposterior dimension and the mandibular angle in
dry human mandibles. Anat. Rec. 294 (8): 1319–1325.
Askar, H., Di Gianfilippo, R., Askar, G. etal. (2018).
Morphometric analysis of the mental foramina, accessory
mental foramina, and anterior loops. Acta Sci. Dent. Sci.
2(1): 126–132.
Barker, B.C.W. (1972). Multiple canals in the rami of
mandible. Oral Surg. Oral Med. Oral Pathol. 34 (3):
384–389.
Barker, B.C.W. and Davies, P.L. (1972). The applied anatomy
of the pterygomandibular space. Br. J. Oral Surg.
10(1): 43–55.
Baumel, J.J., Vanderheiden, J.P., and McElenney, J.E. (1971).
The auricolotemporal nerve of man. Am. J. Anat. 130 (4):
431–440.
Benham, N.R. (1976). The cephalometric position of the
mandibular foramen with age. J. Dent. Child. 43 (4):
233–237.
Bennett, S. and Townsend, G. (2001). Distribution of the
mylohyoid nerve: anatomical variability and clinical
implications. Aust. Endod. J. 27 (3): 109–111.
Berns, J.M. and Sadove, M.S. (1962). Mandibular block
injection: a method of study using an injected radiopaque
material. J. Am. Dent. Assoc. 65 (6): 735–745.
Biermann, H. (1943). Die chirurgische Bedentung der
Lagevariationen der Arteria maxillaries. Anat. Anz. 94
(18–19): 289–309.
Bilecenoglu, B. and Tuncer, N. (2006). Clinical and
anatomical study of the retromolar foramen and canal.
J. Oral Maxillofac. Surg. 61 (10): 1493–1497.
t.me/Dr_Mouayyad_AlbtousH
References 47
https://t.me/med1917
Blair, E.A. and Erlanger, J. (1939). Propagation and extension
of the excitatory effects on the nerve action potentials
across nonresponding internodes. Am. J. Physiol.
126(1): 97–108.
Bremer, G. (1952). Measurements of special significance in
connection with anesthesia of the inferior alveolar nerve.
Oral Surg. Oral Med. Oral Pathol. 5 (9): 966–988.
Carter, R.B. and Keen, E.N. (1971). The intramandibular course
of the inferior alveolar nerve. J. Anat. 108 (3): 433–440.
Chapnick, L. (1980). A foramen on the lingual of the
mandible. J. Can. Dent. Assoc. 46 (7): 444–445.
Coleman, R.D. and Smith, R.A. (1982). The anatomy of
mandibular anesthesia: review and analysis. Oral Surg.
Oral Med. Oral Pathol. 54 (2): 148–153.
Correr, G.M., Iwankod, D., Leonardi, D.P. etal. (2013).
Classification of bifid mandibular canals using cone beam
computed tomography. Braz. Oral Res. 27 (6): 510–516.
Denio, D., Torabinejad, M., and Bakland, L.K. (1992).
Anatomical relationship of the mandibular canal to its
surrounding structures in mature mandibles. J. Endod.
18(4): 161–165.
DuBrul, E.L. (1988). Sicher and Dubrul’s Oral Anatomy, 8e.
St. Louis: Ishiyaku EuroAmerica Inc. 257–260.
FCAT (Federative Committee on Anatomical Terminology)
(1998). Terminologia Anatomica. International Anatomical
Terminology. Stuttgart: George Thieme Verlag.
Frommer, J., Mele, F.A., and Monroe, C.W. (1972). The possible
role of the mylohioid nerve in mandibular posterior tooth
sensation. J. Am. Dent. Assoc. 85 (1): 113–117.
Galbreath, J.C. and Eklund, M.K. (1970). Tracing the course
of the mandibular block injection. Oral Surg. Oral Med.
Oral Pathol. 30 (4): 571–582.
Garg, A. and Townsend, G. (2001). Anatomical variation of
the sphenomandibular ligament. Aust. Endod.
J. 27(1): 22–24.
Gershenson, A., Nathan, H., and Luchang, K.E. (1986).
Mental foramen and mental nerve: changes with age.
ActaAnat. (Basel) 126 (1): 21–28.
Gowgiel, J.M. (1992). The position and course of the
mandibular canal. J. Oral Implamtol. 18 (4): 383–385.
Gülekon, N., Anil, A., Poyraz, A. etal. (2005). Variations in
the anatomy of the ariculotemporal nerve. Clin. Anat.
18(1): 15–22.
Harn, S.D. and Durham, T.M. (2003). Anatomical variations
and clinical implications of the artery to the lingual nerve.
Clin. Anat. 16 (4): 294–299.
Harvey, W. (1970). The mandibular foramen and its position
in relation to anaesthesia of the inferior alveolar nerve.
Glasgow Dent. J. 1 (2): 22–27.
Haveman, C.W. and Tebo, H.G. (1976). Posterior accessory
foramina of the human mandible. J. Prosth. Dent. 35 (4):
462–468.
Hayward, J., Richardson, E.R., and Malhotra, S.K. (1977).
Themandibular foramen: its anteroposterior position.
OralSurg. Oral Med. Oral Pathol. 44 (6): 837–843.
Heasman, P.A. (1988). Variation in the position of the inferior
dental canal and its significance to restorative dentistry.
J. Dent. 16 (1): 36–39.
Heasman, P.A. and Beynon, A.D.G. (1987). Clinical
considerations from axon–myelin relationship in human
inferior alveolar nerve. Int. J. Oral Maxillofac. Surg. 16 (3):
346–351.
Hendy, C.W. and Robinson, P.P. (1994). The sensory
distribution of the buccal nerve. Br. J. Oral Maxillofac.
Surg. 32 (6): 384–386.
Hetson, G., Share, J., Frommer, J., and Kronman, J.H. (1988).
Statistical evaluation of the position of the mandibular
foramen. Oral Surg. Oral Med. Oral Pathol. 65 (1): 32–34.
Huang, H., Liu, P., Li, X. etal. (2013). Mandibular incisive
canal by cone beam CT (English abstract). Hua Xi Kon
Quiang Yi Xue Za Zhi 31 (5): 479–482.
Ikeda, K., Ho, K.-
V.M. (1996). Multiplanar MR and anatomic study of the
mandibular canal. Am. J. Neuroradiol. 17 (3): 579–584.
Jablonski, N.G., Cheng, C.M., and Cheung, H.M. (1985).
Unusual origins of the buccal and mylohioid nerves. Oral
Surg. Oral Med. Oral Pathol. 60 (5): 487–488.
Jastak, J.T., Yagiela, J.A., and Donaldson, D. (1995). Local
Anesthesia of the Oral Cavity. Philadelphia: WBSaunders
Company. 119.
Kadanoff, D., Mutafou, S.T., and Jordanov, J. (1970). Über die
Hauptöffunungen resp. Incisure des Gesichtsschädels
(Incisura frontalis sen Foramen frontale, Foramen
supraorbitale sen Incisura supraorbitalis, Foramen
infraorbitale, Foramen mentale). Gegenbaurs Morphol.
Jahrb. 115 (1): 102–118.
Kafalias, M.C., Gow-
The Gow–Gates technique for mandibular block
anesthesia. A discussion and mathematical analysis.
Anesth. Prog. 34 (4): 142–149.
Kang, J.- H., Lee, K.- S., Oh, M.- G. etal. (2014). The incidence
and configuration of the bifid mandibular canal in Koreans
by using cone beam computed tomography. Imaging Sci.
Dent. 44 (1): 53–60.
Kay, L.W. (1974). Some anthropologic investigation of interest
to oral surgeons. Int. J. Oral Surg. 3 (6): 363–379.
Khoury, J.N., Mihailidis, S., Ghabriel, M., and Townsed,
G. (2010). Anatomical relationship within the human
pterygomandibular space: relevance to local anesthesia.
Clin. Anat. 23 (8): 936–944.
Khoury, J.N., Mihailidis, S., Ghabriel, M., and Townsed,
G. (2011). Applied anatomy of the pterygomandibular
space: improving the success of inferior alveolar nerve
blocks. Aust. Dent. J. 56 (2): 112–121.
C., Nowicki, B.H., and Haughton,
Gates, G.A.E., and Saliba, G.J. (1987).
t.me/Dr_Mouayyad_AlbtousH
Applied Anatomy II: Mandibular Arch
https://t.me/med1917
48
Kiesselbach, J.E. and Chamberlain, J.G. (1984). Clinical and
anatomic observations on the relationship of the lingual
nerve to the mandibular third molar region. J. Oral
Maxillofac. Surg. 43 (9): 565–567.
Kilic, C., Kamburogluk, K., Ozen, T. etal. (2010). The
position of the mandibular canal and histologic feature of
the inferior alveolar nerve. Clin. Anat. 23 (1): 34–42.
Kim, H.J., Kwak, H.H., Hu, K.S. etal. (2003). Topographic
anatomy of the mandibular nerve branches distributed on
the two heads of the lateral pterygoid. Int. J. Oral
Maxillofac. Surg. 32 (4): 408–413.
Koivisto, T., Chiona, D., Milroy, L.L. etal. (2016). Mandibular
canal location: coneexamination. J. Endod. 42 (7): 1018–1021.
Kuribayashi, A., Watanabe, H., Imaizumi, A. etal. (2010).
Bifid mandibular canals: cone beam computed
tomography. Dentomaxillofac. Radiol. 39 (4): 235–239.
Lacouture, C., Blanton, P.L., and Hairston, L.E. (1983). The
anatomy of the maxillary artery in the infratemporal fossa
in relationship to oral injections. Anat. Rec. 205 (3): 104A.
Lee, M.- H., Kim, H.- J., Kim, D.K., and Yu, S.- K. (2015).
Histologic features and fascicular arrangement of the
inferior alveolar nerve. Arch. Oral Biol. 60 (12): 1736–1741.
Lipski, M., Lipska, W., Motyl, S. etal. (2013). Anatomy of the
pterygomandibular space– clinical implication and review.
Folia Med. Cracov. 53 (1): 79–85.
Littner, M.M., Kaffe, I., Tamse, A., and Dicapua, P. (1986).
Relationship between the apices of the lower molars and
mandibular canal– a radiographic study. Oral Surg. Oral
Med. Oral Pathol. 62 (5): 595–602.
Liu, T., Xia, B., and Gu, Z. (2009). Inferior alveolar canal
course: a radiographic study. Clin. Oral Implant. Res.
20(11): 1212–1218.
Löfgren, A.B. (1957). Foramina retromolaria mandibulae. A
study on human skulls of nutrient foramina situated in the
mandibular retromolar fossa. Odontol. Tidskr. 65: 552–573.
Lotric, N. (1956). Foramen mentale. Morphological and
topographical investigations. Excerpta Med. (Sect. 1) 10 (6):
236. (abstract 1093).
Madeira, M.C., Percinoto, C., and Silva, M.C. (1978). Clinical
significance of supplementary innervations of the lower
incisor teeth: a dissection study of the mylohyoid nerve.
Oral Surg. Oral Med. Oral Pathol. 46 (5): 608–614.
Malamed, S.F. (2004). Handbook of Local Anesthesia, 5e.
St.Louis (MI): Elsevier-
Mardinger, O., Chaushu, G., Arensburg, B. etal. (2000).
Anatomic and radiographic course of the mandibular
incisive canal. Surg. Radiol. Anat. 22 (3–4): 157–161.
Martani, F. and Stefanini, F. (1964). Contributio statistico,
morfologico e topográfico allo studio del foro mentoniero
in mandibole umane non vitali. Mondo Odontostomatol.
6:705–717.
beam computed tomography
Mosby. 183.
Menke, R.A. and Gowgiel, J.M. (1979). Short-
anesthesia at the mandibular foramen. J. Am. Dent. Assoc.
99 (1): 27–30.
Murphy, T.R. and Grundy, E.M. (1969). The inferior alveolar
neurovascular bundle at the mandibular foramen. Dent.
Pract. Dent. Rec. 20 (2): 41–48.
Mwaniki, D.L. and Hassanali, J. (1992). The position of
mandibular and mental foramina in Kenyan African
mandibles. East Afr. Med. J. 69 (4): 210–213.
Naitoh, M., Hiraiwa, Y., Aimiya, H., and Ariji, E. (2009).
Observation of bifid mandibular canal using conecomputed tomography. Int. J. Oral Maxillofac. Implants
24(1): 155–159.
Naitoh, M., Nakahara, K., Snenaga, Y. etal. (2010).
Comparison between conetomography depicting mandibular neurovascular canal
structures. Oral Surg. Oral Med. Oral Pathol. 109 (1):
e25–e31.
Namking, M., Boonruangsri, P., Woraputtaporn, W., and
Güldner, F. (1994). Communication between the facial and
auriculotemporal nerves. J. Anat. 185 (Pt 2): 421–426.
Nevin, M. and Putterbaugh, P.G. (1949). Conduction,
Infiltration and General Anesthesia in Dentistry, 5e.
NewYork: Dental Items of Interest Publishing Co. Inc. 179.
Nicholson, M.L. (1985). A study of the position of the
mandibular foramen in the adult human mandible. Anat.
Rec. 212 (1): 110–112.
Novitzky, J. (1938). Sensory nerves and anesthesia of the
teeth and jaws. Mod. Dent. 5 (1): 5–10.
Oliveira-
Olivier, E. (1927). Le canal dentaire inferiour et son nerf chez
Orhan, K., Aksoy, S., Bilecenoglu, B. etal. (2011). Evaluation
Ossenberg, N.S. (1986). Temporal crest canal: case report and
Palma, L.F., Almeida, F.S.O., Lombardi, L.A. etal. (2020). Is
Petersen, J.K. (1971). The mandibular foramen block.
Phillips, W.H. (1943). Anatomic considerations in local
Santos, C., Souza, P.H.C., Berti- Couto, S.A. etal.
(2012). Assessment of variations of the mandibular canal
through cone beam computed tomography. Clin. Oral
Invest. 16 (2): 387–393.
l’adulte. Ann. Anat. Path. Anat. Norm. Med- Chir (Paris)
4(9): 975–987.
of bifid mandibular canals with conetomography in a Turkish adult population: a retrospective
study. Surg. Radiol. Anat. 33 (6): 501–507.
statistics on a rare mandibular variant. Oral Surg. Oral
Med. Oral Pathol. 62 (1): 10–12.
inferior oclusal plane a reliable anatomic landmark for
inferior alveolar nerve block? A study on dry mandibles of
Brazilian adults. Morphologie 104 (344): 59–63.
Aradiographic study of the spread of the local analgesic
solution. Br. J. Oral Surg. 9 (21): 126–138.
anesthesia in dental surgery. Anesth. Analg. 22 (1): 5–14.
beam and multislice computed
needle block
beam
beam computed
t.me/Dr_Mouayyad_AlbtousH
References 49
https://t.me/med1917
Pires, C.A., Bissada, N.F., Becker, J.J. etal. (2012). Mandibular
incisive canal: cone beam computed tomography. Clin.
Implant Dent. Relat. Res. 14 (1): 67–73.
Pogrel, M.A., Schmidt, B.L., Sambajon, V., and Jordan,
R.C.K. (2003). Lingual nerve damage due to inferior
alveolar nerve blocks. A possible explanation. J. Am. Dent.
Assoc. 134 (2): 195–199.
Pogrel, M.A., Dorfman, D., and Fallah, H. (2009). The
anatomic structure of the inferior alveolar neurovascular
bundle in the third molar region. J. Oral Maxillofac. Surg.
67 (11): 2452–2454.
Pretterklieber, M.L., Skopakoff, C., and Mayr, R. (1991). The
human maxillary artery reinvestigated: I. Topographical
relations in the infratemporal fossa. Acta Anat. 142 (4):
281–287.
Roberts, G.D. and Harris, M. (1973). Neuropraxia of the
mylohyoid nerve and submental analgesia. Br. J. Oral Surg.
11 (2): 110–113.
Roda, R.S. and Blanton, P.L. (1994). The anatomy of local
anesthesia. Quintessence Int. 25 (1): 27–38.
Rood, J.P. (1977). Some anatomical and physiological causes
of failure to achieve mandibular analgesia. Br. J. Oral Surg.
15 (1): 75–82.
Rood, J.P. (1978a). The organization of the inferior alveolar
nerve and its relation to local anesthesia. J. Dent. 6 (4):
305–310.
Rood, J.P. (1978b). The diameters and intermodal lengths of
the myelinated fibers in human inferior alveolar nerve.
J. Dent. 6 (4): 311–315.
Rouviere, H. (1976). Compendio de anatomía y disección.
Ediciones Científico Técnicas. Barcelona: Masson(Reprint of the 3rd edition, 1959). 160.
Schejtman, R., Devoto, F.C.H., and Arias, N.H. (1967). The
origin and distribution of the elements of the human
mandibular retromolar canal. Archs. Oral Biol. 12 (11):
1261–1267.
Shaw, M.D. and Fierst, P. (1988). Clinical prosection for
dental gross anatomy: a medial approach to the
pterygomandibular space. Anat. Rec. 222 (3): 305–308.
Shiller, W.R. and Wiswell, O.B. (1954). Lingual foramina of
the mandible. Anat. Rec. 119 (3): 387–390.
Shiozaki, H., Abe, S., Tsumori, N. etal. (2007). Macroscopic
anatomy of the sphenomandibular ligament related to the
inferior alveolar nerve block. Cranio 25 (3): 160–165.
Sicher, H. (1946). The anatomy of the mandibular anesthesia.
J. Am. Dent. Assoc. 33 (23): 1541–1557.
Salvat
Sicher, H. (1950). Aspects in the applied anatomy of local
anesthesia. Int. Dent. J. 1 (1): 70–82.
Simon, B. and Kömives, O. (1938). Dimensional and
positional variations of the ramus of the mandible. J. Dent.
Res. 17 (2): 125–149.
Singh, S. (1981). Aberrant buccal nerve encountered at the
third molar surgery. Oral Surg. Oral Med. Oral Pathol.
52(2): 142.
Sittitavornwong, S., Babston, M., Denson, D. etal. (2017).
Lingual nerve measurements in cadaveric dissections:
clinical applications. J. Oral Maxillofac. Surg. 75 (6):
1104–1112.
Starkie, C. and Stewart, D. (1931). The intra-
course of the inferior dental nerve. J. Anat. 65 (Pt 3):
319–323.
Stein, P., Brueckner, J., and Milliner, M. (2007). Sensory
innervations of mandibular teeth by the mylohyoid nerve:
implications in local anesthesia. Clin. Anat. 20 (6): 591–595.
Stewart, D. (1932). The innervations of the dental tissues and
its importance in regional anaesthesia. Br. Dent. J. 53 (6):
277–284.
Stewart, D. and Wilson, S.L. (1928). Regional anaesthesia and
innervations of the teeth. Lancet 212 (5486): 809–811.
Sutton, R.N. (1974). The practical significance of mandibular
accessory foramina. Aust. Dent. J. 19 (3): 167–173.
Takeuchi, T. (1993). The study of volume and shape of
pterygomandibular space by computed tomography. J. Jpn.
Dent. Soc. Anesthesiol. 221: 293–310. (In Japanese).
Turner, M.B. (1864). LXXIII. On some variations in the
arrangement of the nerves of the human body. Nat. Hist.
Rev. 4: 612–617.
Via, W.F. (1953). The pterygomandbular space in relation to
effective mandibular block anesthesia for children. J. Dent.
Child 20: 105–110.
Watson, J.F. (1973). Appendix: some anatomic aspects of the
Gow–Gates technique for mandibular anesthesia. Oral
Surg. Oral Med. Oral Pathol. 36 (3): 328–330.
Wilson, S., Johns, P., and Fuller, P.M. (1984). The inferior
alveolar and mylohioid nerves: an anatomical study and
relationship to local anesthesia of the anterior mandibular
teeth. J. Am. Dent. Assoc. 108 (3): 350–352.
Yu, S.-
K., Kim, S., Kang, S.G. etal. (2015). Morphological
assessment of the anterior loop of the mandibular canal in
Koreans. Anat. Cell Biol. 48 (1): 75–80.
Zivanovic, S. (1970). Some morphological characters of the
East African mandible. Acta Anat. 77 (1): 109–119.
mandibular
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4
The Peripheral Nerve andLocal Anesthesia
This chapter reviews the microanatomy of peripheral
nerves, nerve cell membranes, neurophysiology, and the
mechanism governing local anesthetic action.
Peripheral Nerve Microanatomy
Neurons
Nerve cells, called neurons, are the anatomic and functional units of the nervous system. While all human cells
are characterized by a difference in potential (voltage)
across their membranes, with a negatively charged interior
and positively charged exterior near the surface, only muscle and nerve cells are excitable, meaning that they are able
to alter that potential in response to a stimulus. Neurons,
moreover, can convey electrical impulses along their membranes between the central nervous system (CNS) and the
rest of the body, and vice versa. Neurons have three main
constituents.
● The body, soma, neurocyton, or perikaryon (peri= around,
karyon = nucleus), the bulbous part of the cell that
contains the nucleus and subcellular organelles (endoplasmic reticulum [ER], Golgi apparatus, mitochondria,
etc.), provides vital metabolic support for the entire neuron.
● The dendrites (dendron = tree branch) are thin cyto-
plasmic filaments projecting off the cell body. They
receive electrochemical impulses that they propagate to
the soma.
● The axon, a longer and thicker extension than the den-
drites, carries electrochemical impulses from the soma to
other organs and nerves.
Depending on function and morphology, neurons can
be divided into three basic types: (i) motor or efferent
(typically multipolar) neurons that conduct impulses from
the Central Nervous System (CNS) to effectors (such as
muscles); (ii) sensory or afferent (pseudo-
unipolar or unipolar)
neurons, discussed below; and (iii) association or interneurons.
Sensory Neurons
These cells are also known as unipolar or pseudo- unipolar
neurons because the single axon (trunk or extension) that
projects off the body subsequently divides into two. One
part courses to the periphery, ending in this case in the
gums, teeth, or bones, where sensory receptors capture
stimuli for propagation to the soma, while the other carries
stimuli to other CNS neurons. Although anatomically the
former would be a dendrite and the latter an axon, as functionally they act as a single long axon, thus that is the term
used for both (Figure4.1).
The body of these neurons lies not in the CNS but in the
dorsal root ganglion (spinal cord), while the maxillofacial
sensory nerves lie in the semilunar or trigeminal
(Gasserian) ganglion.
Axons
Axons are the trunks or axis cylinders that extend off the
bodies of sensory nerves. They are sheathed by a series of
cells known as Schwann cells. Although the functions of
the latter are not fully understood, they are associated with
the modulation of nervous conduction, the provision of
direct metabolic support in the form of energy or protein
synthesis, and the release of trophic factors to enhance
axon function. Together the axon and its Schwann cells,
called nerve fibers, constitute a functional element separated from the surrounding tissue by a basal lamina. Axons
consist essentially of two parts.
● The axoplasm or neuron cytoplasm, like the cytoplasm
in the soma, is a viscous liquid five times denser than
water. It contains subcellular organelles such as
Local Anesthesia in Dentistry: A Locoregional Approach, First Edition. Jesús Calatayud and Mana Saraghi.
© 2024 John Wiley & Sons Ltd. Published 2024 by John Wiley & Sons Ltd.
Companion website: www.wiley.com/go/Calatayud/local
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Figure4.1 Sensory or unipolar neuron. Source: Redrawn from
Ion pore
Ion pore
Ion channel
membrane
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Cajal (1899).
mitochondria or the ER and provides the cell membrane
with metabolic support (Meymaris1975).
● The nerve membrane or axolemma or neurilemma that
separates the axoplasm from extracellular liquids is the
element around which this discussion revolves as it is
where nervous excitation and electrochemical conduction take place. It is discussed in detail below.
Membranes
The cell membrane is a semipermeable structure just
7–10 nanometers (nm) thick that separates the axoplasm
from extracellular fluids. Although the molecular organization of the membrane is not understood in full detail, a
number of important features have been described (Singer
and Nicolson 1972; Meymaris 1975; Wildsmith 1986;
Guyton and Hall2007).
Peripheral Nerve Microanatomy 51
+
hydrosoluble ions such as sodium (Na
+
) while allowing the flow of liposoluble compounds.
(K
) and potassium
2) Cholesterol and neutral lipids (13%) dissolved in the
phospholipid bilayer.
3) Proteins (55%) distributed along and across the mem-
brane. There are two types: (i) integral or intrinsic proteins spanning the entire width of the membrane from
the axoplasm to the extracellular fluids; (ii) peripheral
or extrinsic proteins found only on either the inner or
outer surface that do not penetrate the entire membrane. All these proteins have many functions, such as
antigen or other markers, receptors (for hormones for
instance), enzymatic control of reactions on the membrane surface or molecular transport across the membrane. The fourth is the type of protein of major
interest here.
4) Small amounts (3%) of carbohydrates on the outer sur-
face only, bound to lipids (glycolipids) or proteins
(glycoproteins).
As the membrane is not solid its constituent phospholipids
and proteins can move laterally. The proteins, which float in
a “sea” of phospholipids, are not uniformly distributed
(Figure4.2) but change constantly in keeping with the socalled “fluid mosaic model of the plasma membrane” (Singer
and Nicolson1972). Some however, bound to the cytoskeletal
proteins, help maintain the general shape of the cell.
Nerve Fibers andMyelin
Schwann cells may surround the axon in one of two ways,
either forming myelin or not.
Myelinated Fibers
Myelinated fibers are enveloped in a layer of myelin, a substance comprising alternating concentric layers of lipids
and proteins. These layers are actually the Schwann cell
Cell
1) It has a phospholipid bilayer (25%) in which each layer
consists of (i) polar (hydrophilic) phosphate groups oriented toward the membrane surface, in other words, in
the inner layer toward the axoplasm and in the outer
toward the extracellular fluids, and (ii) apolar or nonpolar (hydrophobic) fatty acid groups in the center, oriented inward in both layers and attracted to one another.
The hydrophobic part blocks the flow of water and
Figure4.2 Diagram of cell membrane.
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Nucleus of
Schwann
Node of
Axon Myelin
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52
schwann cell
Figure4.3 Myelinated fiber, Schwann cell, and nodes of
Ranvier. S
ource: Redrawn from De Jong (1977).
cell
ranvier
membrane that winds around the axon with scarcely any
cytoplasm between layers (Figure4.3).
The most peripheral layer of the myelin sheath, the
Schwann cell cytoplasm where the nucleus is located, is
called the neurilemma or neurolemma (Jastak etal.1995).
At regular 0.2–0.3-
mm intervals in myelinated fibers, the
neurilemmas of adjacent Schwann cells interconnect. As
there is no myelin in this region the cover narrows, exposing the axon directly to extracellular fluids. Myelin affords
powerful insulation that drastically reduces ion flow in the
membrane by impeding contact between it and extracellular fluids because it leaves a tiny extracellular space, measuring barely 10–15 nm.
These gaps in the myelin layer, known as the nodes of
Ranvier (Figure4.3), while just 0.5–1.5 microns (μm) long,
are extraordinarily important. It is here that ionic exchange
takes place between the axoplasm close to the membrane
and the extracellular fluids and where local anesthetics act.
The larger the diameter of the axon the thicker the myelin sheath and the greater the internodal distance (distance
from one node of Ranvier to the next). Accordingly, the
nodes of Ranvier are spaced at a fairly constant 100–200
times the axon diameter (Jastak etal.1995). In myelinated
fibers the nervous impulse jumps from node to node of
Ranvier (Tasaki1953) in “saltatory conduction”, accelerating propagation speed and requiring less ion movement.
This arrangement is more efficient than conduction in
unmyelinated axons because it calls for less energy and less
metabolic activity.
The myelin sheath itself is interrupted at intervals by
oblique incisions, Schmidt–Lantermann clefts, that connect it to the exterior and enhance elasticity by stretching
the nerve (Heasman and Beynon1987).
Unmyelinated Fibers
Unmyelinated fibers have an axon surrounded by the
myelin- free part of Schwann cells. In these fibers the
Schwann cell membrane and cytoplasm normally sheathe
several axons (Wildsmith1986). Nerve impulse conduction
in smaller diameter unmyelinated fibers is continuous,
slower, and more energy- intensive than in myelinated axons.
Nerve Fiber Classification
Table4.1 lists the three main categories, A, B, and C, of
peripheral nerve fibers and their subdivisions. Axon diameter, location, and function are also given in the table, along
with the presence or otherwise of myelination.
Nerve impulse conduction depends primarily on two factors (Jack1975): diameter, the greater the speedier, and the
presence of myelin, which enhances speed. Myelinated
Afibers, which are the thickest, exhibit the highest conduction speed. Conversely, C fibers are the thinnest and
slowest. A delta (Aδ) and B fibers are often nearly undistinguishable and can only be differentiated on the grounds of
electrophysiological properties not shown in the table
(Jastak etal.1995). The following are the fibers of greatest
interest here.
● Myelinated Aδ fibers conduct first (sharp, immediate,
and localized) pain that disappears with the pain
stimulus.
● Type IV sensorial unmyelinated polymodal C fibers
transmit second (diffuse or scantly localized, dull) pain
that persists beyond the duration of the stimulus.
The first mandibular premolar dental pulp has been
shown to have around 300–500 Aδ fibers and 1500–1800
polymodal C fibers (Johnsen etal.1983). While the electrical pulp tester stimulates the former, it barely affects the
latter (Lin and Chandler2008; Abd-
Elmeguid and Yu2009;
Sampaio et al. 2012). Furthermore, polymodal C fibers
seems more resistant to the effects to local anesthetics
(Saha etal.2016).
Peripheral Nerve Structure
Peripheral nerve trunks comprise hundreds or thousands
of myelinated and unmyelinated nerve fibers, supported
and protected by surrounding connective tissue (Figure4.4)
consisting of the following structures starting from the
innermost layer (closest to the nerve) to the outermost
layer (Sunderland1965; Wildsmith1986):
● The endoneurium, the innermost sheath of connective
tissue, runs parallel to, bathes, and separates the nerve
fibers, and its capillaries provide nutrients for the tissues
(Wildsmith1986). These blood vessels form the intrinsic
system, are mainly nutritive, and have minimal adrenergic receptors (Myers and Heckman1989).
● The perineurium is connective tissue surrounding the
endoneurium that runs concentrically, obliquely, and
parallel to nerve fibers, bundling from 500 to 1000 axons
known as a fascicle. The perineurium carries blood vessels (vasa nervorum) which, in the form of a terminal
capillary and precapillary network, penetrate the
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Peripheral Nerve Microanatomy 53
Epineur
Fascicle
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Table4.1 Classification ofperipheral nerve fibers.
Type of fiber Myelin Diameter (μm) Speed (m/s) Location Function
Aα +++
Motor 12–20 65–120 Muscle Motor
Ia sensorial 13–22 70–130 Muscle spindle Proprioceptive
Ib sensorial 12–120 65–120 Tendon Proprioceptive
Aβ ++
Motor 7–14 40–80 Muscle Motor
II sensorial
Aγ ++
Motor 2–10 10–50 Muscle Motor
II sensorial
Aδ +
III sensorial 1–7 5–40 Various First pain
B +
Preganglionic autonomic
(sympathetic)
C −
Postganglionic autonomic
(sympathetic)
IV sensorial 0.2–2 0.2–2 Various Second pain
a
Not distinguishable from one another.
Source: Data from Jastak etal. (1995).
a
a
5–15 20–80 Tendon Proprioceptive
5–15 20–80 Tendon Proprioceptive
Temperature
Pressure
1–5 4–25 Heart
Smooth muscle
Gland
0.2–2 0.2–2 Heart
Smooth muscle
Gland
Motor
Motor
Secretion
Motor
Motor
Secretion
Temperature
Pressure
Visceral
endoneurium. These blood vessels form the extrinsic system and are under adrenergic control (Myers and
Heckman1989). The innermost layer of the perineurium
consists of a sort of membrane with several layers of cells
known as the perilemma or perineural epithelium that
hampers the diffusion of the anesthetic solution into
nerve fascicles (Sunderland1965; Shanthaveerappa and
Bourne1966).
● The epineurium, lax connective tissue containing
some fatty cells, surrounds fascicles and holds them
together. Its blood vessels form a vascular network
(an extrinsic system) that responds to adrenergic stimulation and anastomose with intrinsic vessels (Myers
and Heckman1989). Its dense, thick outermost layer,
the external epineurium, does not interfere with local
anesthetic diffusion. The epineurium accounts for
30–75% of the total cross- section of peripheral nerves
(Sunderland1965).
Vasa
nervorum
ium
Epineural
sheath
Perineurium
Endoneurium
Nerve fiber
Figure4.4 Peripheral nerve structure.
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