The 'TEMPORAL BONE - Keystone of the Cranium
One of the key factors in temporomandibular joint
dysfunction involves distortion of the temporal bone. In an over
temporal bone represents the door frame and the mandibular condyle
acts as the movable door if any distortion occurs to the frame
it is a reasonable ssumption to expect a dysfunction of the door
The temporal bones consist of three main parts the internal petrous
portion the external squama and mastoid sections
squama gives off a zygomatic process which extends forward and
articulates with the malar bone and acts as the shock absorber
for the TM joint in the cranial scheme the temporal bone articulates
with the occiput parietals sphenoid malar and mandibular condyles
its primary motion derives from the occiput which gently moves
the temporal bones into internal and external rotation during
the respiratory phases of expiration and inspiration respectively
Two of the primary muscles of mastication.
Temporalis and masseter muscles. have a direct influence on temporal
bone movement,. The large, fan-shaped temporalis muscle has part
of its origin on the temporal squama and inserts on the mandible
at the coronoid process and its anterior border.
Spasm of this
muscle will provide a powerful down-ward and anterior force a
powerful down-word and anterior force upon the squama when the
posterior teeth occlude. This force will have the effect of causing
an external rotation i.e. the superior border of squama will move
anteriorly and laterally while the mastold tips move superiorly,
posteriorly, and medially.
The mandibular condyles compensate by moving posteriorly and medially
within the glenoid fossa. Intermal rotation of the temporal follows
a movement that is directly opposite to that of extermal rotation-the
mastoid tips move inferiorly, anteriorly and laterally while the
superior order of the squama moves posteriorly and medially.
The condyle compensates in an anterior and lateral position within
the fossa. Spasm of the sternocleidomastoid, splenius capitis,
longus capitis and digastric muscles will induce an intermal temporal
Balancing the movements of the temporal bone if the function of
the stylohyoid and styloglossus muscles. These muscle attachments
have their origin on the styloid processes and during con-traction
function to inhibit and balance temporal motion. Of further
interest is the fact that temporal bone rotation affects the ten-sion
on the tentorium cerebelli.
Spasms of the temporalis, masse-ter, sternocleidomastoid, spienius
capitus, longus capitus, stylo-hyoid, and stylogiossus muscles
all can effect a temporal bone distortion.
Extensive dural membrane attachments to the temporal bone make
it vulnerable to distortion from other areas of the dural tube.
The temporal bone has extensive sutural articulations with
the occiput, parietal, and spnenoid bones it functions between
the two main cranial bone movers-occiput sphenoid bones-and provides
a portion of the cranial base.
Proper dynamics of temporal bone equilibrium is essential to a
well functioning TM joint and to the entire structural scheme.
Noxious influences are constantly working to upset this delicate
balance. Distortions of muscles, fasciae, dural membranes, sutures,
cerebrospinal fluid dynamics, etc. are all potential disruptive
The maxillary bone is of particular importance to the dentist.
Distortion of this bone can be the etiological factor in facial
pain, neuralgia, sinusitis, rhinitis, and odontalgia in the absence
of frank pathology. Basic neuroanatomy will reveal the second
division of the trigeminal nerve (V-2) and its posterior, middle
and anterior alveola branches, greater palatine, nasopalatine,
pteryopalatine ganglion and infraorbital nerves are closely related
to the maxillaty bone. Often facial distortions can be attributed
to maxillary bone dysfunction Gross anatomy exhibits attachments
of the medial ptetygoid, buccinator, zygomaticus major, elevator
labi superior. levator anguli oris, and obigularis oculi to the
maxilla. Clinically, one often observes facial distortions and
eye dys-functional movement as a result of maxillary distortions.
In the cranial scheme (excluding the three ear ossicles) the maxilla
directly articulates with 45% of the cranial bones.
Sutural attachments are shared with the malar, frontal, ethmoid,
vomer lacrimal, inferior nasal concha, palatine, sphenoid, and
the other half of the maxillary bone.