Inferior Alveolar Technique

7/30/2019 Inferior Alveolar Technique

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Professor: R. Padmanabhan Adesh University 1

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INFERIOR ALVEOLAR-LINGUAL-LONG BUCCAL NERVE

INJECTION

By executing the inferior alveolar-lingual-long buccal nerve injection,anesthesia is secured for surgical and exodontic measures upon the teeth and the

tissues immediately surrounding them. Actually, the lingual nerve is blocked in

the course of the inferior alveolar nerve injection, while the long buccal nerve

requires a separate puncture in a different region. At the present time, this form

of block anesthesia is carried out by three different techniques:

1. The Fischer technique, known as the "1 , 2, 3" method.

2. The single path technique, known as the "1" method.3. The straight line modification of the single path technique

THE FISCHER OR '1, 2, 3" TECHNIQUE

This method of blocking the inferior alveolar nerve by the intraoral route is

older than the single path technique, and has many staunch-adherents who, after

modifying it slightly in some instances, claim for it many major advantages

which will be discussed somewhat further on in this chapter. Not its variations,

but the original procedure, will be taken up at this point, first for the right

inferior alveolar nerve and then for the left one.

Fischer or "1, 2, 3" Technique for Right Side.Instruct the patient to keepthe mouth wide open and so adjust the head rest as to maintain the mandibular

occlusal plane parallel tothe floor. Raise or lower the chai r un ti l the subject's

head is on a level with your right shoulder. As a source of illumination for the

recesses of the oral cavity, a surgical headlight is perhaps the most efficient.

Examine the anesthesia tray to ascertain whether the serrated thumb forceps is

within the easy reach. Do not commence any conduction injection unless


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this instrument is at hand to pluck the needle from the tissues, should it

fracture.

Sli de th e ball of th e le ft finger up wa rd an d ba ck war d, starting wit h

the alveolar mucosa on the buccal aspect of the molar teeth, until the sharp

external oblique line is felt. To eliminate the anterior border of the

masseter muscle, request that the patient alternately open and close the

mo uth slowly. I f t he re i s n o a lt e ra ti on in th e hardness of th e ridge, it is

the bone and not the muscle. Palpate for the deepest point of the

concavity on this ridge. Keeping the ball of the finger stationary, rotate the

finger until the radial or thumb side just touches the bucco-occlusal line

angle of th e mo la r te et h , an d th e dorsal surface faces the median li ne .

Note that the fleshy t ip of the finger is now lying in the r e tromolar

fossa, that the edge of the nail is superimposed upon the blunt internal

oblique line; and that the ball the finger is upon the external oblique

line. Without changing its position, scrub the palpating finger-tip and the

adjoining mucous membrane, first with a dry cotton-wound wooden

applicator to remove the mucousand then with the combined surface

ant isep t ic -anes thet ic . Allow atleast thirty seconds for the action of the

drugs. The loaded syringe is now picked Up with the right hand, pen grasp, with

the bevel toward the internal surface of the ramus. The needle recommended for

this injection is 42 mm or 1 5/8 inches long and of gauge No. 22 and 23.

Advancing from the two bicuspids of the left side, the point head of the needle

is made to pierce the mucous membrane at the mid-point of the finger-nail, to a

depth of about '6mm or inch, whereupon the bony obstruction of the internal

oblique line should be encountered. Contact is sufficient; do not engage the

needle-point in the periosteum. Gently swing the syringe back to the right side

until it is parallel to the molar teeth, both in a vertical as wellas in a horizontal


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plane. Holding the syringe lightly, allow the needle-to penetrate a little deeper,

approximately another 6mm or inch. The second movement is designed to

permit the needle to pass the internal oblique line and to bring it into the vicinity

of the lingual nerve. Slowly deposit 0,5cc of anesthetic at this level. If with the

syringe on right side (second position) difficulty is experienced in rounding the

internal oblique line, probe gently with the needle-point until the resistance

disappears and continue for 6 mm. as before.

Having injected for the lingual nerve, the-syringe is carefully brought back to

approximately the first position, i.e., somewhere between the left lateral incisor

and the left first bicuspid, and kept parallel to the floor. Observe that this third

position is not fixed as is the first. The third position varies according to the

inclination of the internal surface of the ramus. The needle is carefully inserted

for an additional depth of 10-15mm or 1 to 1.5 cm. (2/5 to 3/5 inches). If bone is

encountered within these limits, it may be confidently assumed that the

opening of the needle has struck the ramus directly a t the posterior ledge of

the mandibular sulcus, and 1.5 cc of solution is slowly released without

pressure.

After making 'contact with the bone, it is preferable to withdraw the

needle 1 or 2 mm. to prevent injury to the 'periosteum with the resulting

after-pain. The total length of the needle which is buried in the tissues can

readily be calculated as being between 22 -27mm. (7/8 to 1 1/8 inches). Under

no circumstances, except in the case of a patient with an unusually wide ramus,

should the total depth of insertion exceed 1 1/8 inches. For children the normal

length is between 12 to 15 mm, (1/2 to 5/8 inches).


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The width of the ramus can be estimated by placing the thumb in the

subject's cheek and pressing backward, while the index finger palpates the

posterior border of the ramus just below the external ear.

The patient's mouth being half open. In the event that an insertion of 1 1/8

inches fails to reach bone, the needle should be withdrawn until only the bevel

is engaged in the tissues, the syringe swung further posteriorly, to a position

between the two left bicuspids, and then reinserted the proper distance until

contact is made.

By anesthetizing the inferior alveolar nerve, we have assured insensibility of

the teeth of the same side, as well as the mucous membrane supplied by the

terminal branches of he mental nerve, i. e. the gums in the anterior and

bicuspid region. The lingual nerve injection adequately desensitizes the lingual

mucosa. However a small patch of mucous membrane on the buccal aspect of

the molar teeth frequently retains sensation for the very good reason that its

nerve supply is from neither of the nerves mentioned but from the long buccal

branch, which therefore requires a separate injection.

The long buccal nerve injection is simple and almost error-proof.

Consequently, when any surgery or exodontia involving the area innervated by

the long buccal nerve is anticipated, it should be blocked routinely as a time-

saving measure. There are two methods of accomplishing this. Where no

infection is present on the buccal surface of the mandibular molars, simple

submucous infiltration of the tissue just buccal to the tooth to be removed or in

the fold near the disto-buccal angle of the third molar with 0.5 cc. of solution is

sufficient to intercept the fibers of the long buccal nerve.


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An alternate method is to insert the point of the needle beneath the

mucosa about 6mm. or 1/4 inch buccally to the mesial root of the last

molar, with the shaft of the needle held at an angle of about 30 degrees

upward and outward. The point of the needle is then slid along beneath

the mucosa until the region of the distal root of the last molar is reached.

The deposition of 0.5 cc. of anesthetic solution will block the terminal

branches of the long buccal nerve. .

Where infection contraindicates this procedure, the nerve may be blocked by

inserting the same needle used for the inferior alveolar injection into the

mucous membrane about 0.5 inch or little more than 1 cm below a n d

behind the opening of Stenson's duct. After t h e i n i t i a l puncture,

t h e needle is sl id along submucously (without entering t h e

buccinator muscle, i f possible) for about 1.5cm posteriorly, and a

total of 1 cc. of anesthetic deposited during-the progress of the needle. An

excellent way to block the buccinator nerve is described by Dr. E. G. Sloman inhis article "Anatomy and Anesthesia of the Buccinator (Long Buccal) Nerve .

The technique which he evolved for ordinary practice is to make the puncture at

a point 1 cm above the occlusal surface of the lower molars and 4 millimeter

medially to the external oblique ridge in the retromolar fossa. The needle is

directedbackward and slightly outward and is inserted until bone is felt. It is then

withdrawn slightly (2 millimeters) and the solution deposited . In the second

method, which supposes the necessity of injecting still farther distally from the

body of the mandible, an imaginary line is drawn on the surface of the mucous

membrane which follows the course of the buccinator nerve upward in the

temporal muscle. As the author states, in order to select a point at which to

inject, the operator need but to remember that from the point at which the nerveemerges from the temporalis (at the sharp anterior border of the ramus of the


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mandible on a level with the occlusal surfaces of the lower posterior

teeth) it passes upward, medially and very slightly posteriorly, and that

forevery 8mm. of its ascent, it passes 3millimeters medially and about 1

millimeter posteriorly. As it passes upward in the temporalis, it departs

farther and farther from the surface of the bone, but remains (in the lower

four-firths of its course through the muscle) about 3 millimeters from the

surface of the overlying oral mucosa."

Edentulous Mandibles.- Since in these cases, the occlusal surfaces of the

molar teeth are not available as landmarks, the technique just described

must be modified slightly.

Place the hall of the left index finger on the buccal alveolar mucosa in

the right molar region and carefully palpate upward and backward to

determine the deepest point of the concavity on the external oblique line.

Test as described, to eliminate the anterior border of the masseter muscle.

With the ball of the finder resting in the base of the curve on the sharp

outer ridge, turn the hand until the dorsal surface of the finger faces the

median line and the thumb side is 1 cm. or 2/5 inch above the edentulous molar

area. If this step is properly executed, the base of the finger will touch the

incisal tips of the anterior teeth, or will be slightly less than 1 cm. above the

anterior edentulous ridge.

Following the surface sterilization and anesthetization of the mucous

membrane, the first and second positions are completed as outlined, with the

exception that the lower border of the mandible is taken as a guide for the

horizontal position of the syringe, instead of the occlusal surfaces of the molar

teeth. In the third thrust, the needle may*he given a slightly upward


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direction to overcome the tendency to set the site of puncture at too low a level.

Due to the fact that the angle formed by the body and the ramus of the mandible

in the aged is greater than in the young adult, the mandibular foramen will

appear to be higher than usual as compared with the body of the mandible.

Children's Mandible. : Examination of the mandible of a child will

reveal the fact that the relationships of the several landmarks vary

from those existing in the adult's jaw. To compensate for the smaller

size of the bone and for the differing angles, the inferior alveolar-

lingual nerve injection technique is revised to some extent. Thus,

although the "1, 2, 3" positions are continued, the following changes

are instituted:

(a) The level of the first puncture is reduced to 3/8 inch or 10 mm.

above the occlusal surfaces of the molars.

(b) To reach the lingual nerve from the second position, a depth of |inch or

6 mm. is adequate.

(c) The total distance from the mucous membrane to the mandibular

sulcus is 1/2 inch to 3/4 inch (12 mm. to 15 mm.) as compared to twice that

length in the adult.

(d) Finally the needle should take a slightly downward path in proceeding

from the third position toward the mandibular foramen.

Imperfect Anesthesia of the Anterior Teeth Following Inferior Nerve Block. -

Theoretically, anesthesia of the inferior alveolar nerve of any one side

guarantees anesthesia of all parts of that side as far as the median line.

Practically, however, it is found that a certain degree of sensation remains in the

anterior teeth due to the interlacing of the fibers from t he incisive branch of the

unanesthetized inferior alveolar nerve of the opposite side. To insure the

complete desensitization of all nerves ramifying to the anterior teeth, operations


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on these organs should not ho attempted before giving the incisive fossa

injection as described in the chapter on "Infiltration Anesthesia," or an incisive

nerve block a t the mental foramen of the opposite side, or an inferior alveolar

nerve block on the opposite side.

Fischer or "1, 2, 3" Technique for Left Side.- Regardless of which side of the

mandible is to be anesthetized, the left index finger is employed for palpation,

while the right hand manipulates the syringe. The only difference that exists is

that, when injecting the nerve of the left side, either the hands are crossed or the

operator's left hand surrounds the head of the patient. When the correct height of

the puncture is decided upon, it will he found that the thumb side of the left

index finger is now pointing upward (instead of downward as in the case of the

injection for the right side) but that the dorsal surface still faces the median

line. The first position of the syringe is from the right; the second, from the left;

and the third from the right again. In all other respects t h e right and left side

injections are identical.

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Inferior Alveolar Technique