In the present work, the exact position of auditory tube can be located by measuring the distances from posterior end of inferior turbinate, perpendicular distance from clivus, roof of the nasopharynx, distance from anterior arch of atlas.
Table 1: Showing Different Positions and Shape of Pharyngeal Opening of Auditory Tube (All In %) Position of Position/ opening Shape Right Left Below 56 84 Behind 36 16 Above 8 0 Shape of Oval 52 32 opening Triangular 36 48 Round 12 0 Slit Like 0 20 Table 2: Showing the Dimensions and Distance of Pharyngeal Opening of Auditory Tube from Posterior End of Inferior Turbinate, Perpendicular Distance from Clivus, Roof of the Nasopharynx, Anterior Arch of Atlas Width (cm) Height (cm) Parameters Rt Lt Rt Lt Number 25 25 25 25 N mean 0.
The predental space is the space between the odontoid process and the anterior arch of atlas
19) Hypertrophy of the anterior arch of atlas
and disruption of the spinolaminar junction line are radiographic signs associated with, but not specific for, os odontoideum.
Skull two shows fusion of right half of anterior arch of atlas
RESULTS AND DISCUSSION: Atlas vertebra was fused to axis in such a way that odontoid process is deflected markedly backwards and to left uniting with facet at the anterior arch and its summit looks upwards and lying altogether above anterior arch of atlas
and displaced from centrum of axis.
Anterior arch of atlas was partially fused with anterior margin of foramen magnum leaving a slit like gap measuring 16mm transversely between it and the basilar part of occipital bone.
Anterior arch of atlas was partially fused with anterior margin of foramen magnum except for a small foramen in the midline between it and the basilar part of occipital bone.
AA: anterior arch of atlas, RIAF: Right inferior articular facet, LIAF: Left inferior articular facet, RTP: Right transverse process, LTP: Left transverse process, RPA: Right posterior arch, LPA: Left posterior arch & FM: Foramen Magnum.
Odentoid process is hold in position against the posterior aspect of the anterior arch of atlas
by the transverse ligament.
Anterior arch of atlas is partially fused with anterior margin of foramen magnum leaving a gap between it basilar part of occipital bone.
Incomplete fusion of anterior arch of atlas with basilar part of occipital bone is forming a foramen which is situated to the left of midline (fig-7)