The =temporo-hyoid articulation= is an amphiarthrosis, in which the
dorsal angle of the proximal end of the great cornu (Stylo-hyal) is
attached by a short bar of cartilage to the hyoid process of the petrous
temporal bone. The cartilage (Arthrohyal) is about half an inch (ca. 1
to 1.5 cm. ) in length. The chief movement is hinge-like, the axis of
motion passing transversely through both joints.
The =intercornual articulation= is an amphiarthrosis formed by the
junction of the distal extremity of the great cornu with the proximal
end of the small cornu (kerato-hyal). They are united by a very short
piece of cartilage, in which there is usually a small nodule of bone in
the young subject. This nodule, the epihyal or middle cornu, is usually
fused with the great cornu in the adult. The chief movement here is also
hinge-like, the angle between the cornua being increased or diminished.
The =basi-cornual articulation= is a diarthrosis formed by the junction
of each small cornu (kerato-hyal) with the body (basi-hyal). The small
cornu has a concave facet which articulates with the convex facet on
either end of the dorsal surface of the body. The capsule is ample
enough to allow considerable movement, which is chiefly hinge-like. The
movements of the hyoid bone are concerned chiefly in the acts of
mastication and swallowing. In the latter the distal parts of the hyoid
bone are moved forward and upward, carrying the root of the tongue and
the larynx with them, and then return to their former position.