This document studied the position of the mandibular foramen based on measurements taken from 50 human dentate mandibles. It found significant variability between individuals, with the foramen typically located anterior to the midpoint of the ramus. It concluded that the temporal ridge is the best landmark for mandibular block anesthesia, with the foramen located around 11 mm posterior to the ridge on average. Factoring in this anatomical variability could help reduce failures when performing mandibular nerve blocks.

1. THE MANDIBULAR FORAMEN -
- ROLE OF ITS POSITION IN BLOCK
ANAESTHESIA

2. Each mandibular ramus has an
unique, round or oval-shaped
mandibular foramen, which is
the passage place for the nerve
and vascular bundle consisiting
in:
• The inferior alveolar nerve-
ramus of the mandibular nerve;
• The inferior alveolar artery-
ramus of the maxillary artery;
• The inferior alveolar vein-
which flows into the pterigoidyan
or pterigo-maxillary venous
plexus

3. I. The study aimed to:
• Investigate if the classic
opinion concerning the
position of the
mandibular foramen ,
considered to be placed
into the middle of the
mandibular ramus can
be found to be also true
for the romanian
population;
• Assess the posibilities
offered by the
anatomical findings to
reduce failures when
performing mandibular
block anaesthesia;

4. METHODS AND MATERIALS
We used fifty human dentate
mandibles - part of the Reiner’s
collection belonging to the “Carol
Davila” University of Medicine and
Pharmacy in Bucharest

5. The following distances were measured with
maximum accuracy:
1. The anterior edge of the mandibular ramus to the mandibular foramen;
2. The posterior edge of the mandibular ramus to the mandibular foramen;
3. The temporal ridge of the mandibular ramus to the mandibular foramen;
4. The inferior edge of the mandibular ramus to the mandibular foramen;
5. The mandibular notch to the mandibular foramen;
6. The width of the mandibular ramus at the level of the mandibular
foramen.

6. RESULTS

7. DISTANCE FROM THE MANDIBULAR FORAMEN
TO THE ANTERIOR (1) AND POSTERIOR (2)
MARGINS OF THE MANDIBULAR RAMUS
Maxim value Minim value Mean value
1. Left 21,2 mm. 13 mm. 17,1 mm.
Right 21,5 mm. 11,8 mm. 16,6 mm.
2. Left 13 mm. 5 mm. 9 mm.
Right 13 mm. 5 mm. 9 mm.
In 34 cases (68%) assimetry was present between left and right
distances measured from the mandibular foramen to the anterior margin
of the mandibular ramus .
For the distance measured between the mandibular foramen and
the posterior margin of the mandibular ramus the differences between
left and right were encountered in 38 cases ( 76%)

8. DISTANCE FROM THE MANDIBULAR FORAMEN
TO THE TEMPORAL RIDGE ( 3)
Maxim value Minim value Mean value
Left 14 mm. 8 mm. 11 mm.
Right 14,5 mm. 8 mm. 11,25 mm.
There were 34 cases
(68%) in which
different values
were found
comparing the left
and right distances
measured at the
same mandible.

9. DISTANCE FROM THE MANDIBULAR FORAMEN
TO THE INFERIOR MARGIN (4) AND MANDIBULAR
NOTCH (5)
Maxim value Minim value Mean value
4. Left 34 mm. 16 mm. 25 mm.
Right 36 mm. 18 mm. 27 mm.
5. Left 19 mm. 12 mm. 15,5 mm.
Right 19 mm. 12 mm. 15,5 mm.
Left –right differences
were found in 30% of
measured mandibles

10. WIDTH OF THE MANDIBULAR RAMUS (6)
Maxim value Minim value Mean value
Left 36 mm. 27 mm. 31,5 mm.
Right 35,5 mm. 27 mm. 31,2 mm.
In 40 cases
(80%) left-right
differences could
be measured

11. DISCUSSION

12. • The results we obtained are in somehow contradiction with
classic topography data regarding the position of the
mandibular foramen.
Individual differences regarding the position of this foramen
have been found.
• The first important observation reveals the fact that the
mandibular foramen was not found in the middle of the
mandibular ramus, neither in sagittal or vertical planes.
• Secondly, in cases in which the distance between the
mandibular foramen and the anterior margin of the
mandibular ramus was greater, the other mandibular ramus
had a smaller width.
• In the third place, taking into account the mean value of 11
mm. between the temporal ridge and the mandibular foramen,
it seems that the recommended needle penetration during block
anesthesia should better be 10-15 mm. instead of the classic
15-20 mm.

13. CONCLUSIONS
1. A DECREASE OF THE WIDTH OF THE
MANDIBULAR RAMUS ON ONE SIDE IS
ASSOCIATED WITH A SIMILAR INCREASE OF
THE WIDTH OF THE OTHER RAMUS.
2. ATROPHY AND RESORBTION AFFECT MORE
FREQUENTLY THE ANTERIOR MARGIN OF THE
MANDIBULAR RAMUS, COMPARED WITH THE
INFERIOR OR POSTERIOR MARGINS.
3. WHEN PERFORMING EXTRAORAL ACCESS
FOR MANDIBULAR BLOCK ANESTHESIA THE
MEAN DISTANCES WE SHOULD RESPECT ARE
26 MM. FROM THE INFERIOR MARGIN AND 15,5
MM. FROM THE MANDIBULAR NOTCH TO THE
MANDIBULAR FORAMEN.

14. CONCLUSIONS
4. THE MANDIBULAR
FORAMEN HAS BEEN
FOUND TO BE
POSITIONED WHERE THE
ANTERIOR TWO THIRDS
MEET THE POSTERIOR
ONE THIRD OF THE
WIDTH OF THE
MANDIBULAR RAMUS, IN
THE OCCLUSAL PLANE
OF THE INFERIOR TEETH.
THIS CONTRADICTS THE
CLASSIC POSITIONING,
IN THE MIDDLE OF THE
MANDIBULAR RAMUS

15. CONCLUSIONS
5. THE TEMPORAL RIDGE CAN BE CONSIDERED
THE MOST IMPORTANT MARK FOR
MANDIBULAR BLOCK ANESTHESIA; THE
FORAMEN IS FOUND AT APPROXIMATELY 11
MM. POSTERIOR TO THE RIDGE.
6. THE POSITION OF THE MANDIBULAR
FORAMEN MAY REPRESENT A PROBLEM FOR
BLOCK ANESTHESIA OF THE INFERIOR
ALVEOLAR NERVE.
7. TAKING INTO ACCOUNT THE OBSERVATION
WE HAVE MENTIONED, FAILURES REGARDING
THIS KIND OF ANESTHESIA MAY BE REDUCED.