Part 21

Action.—Depresses the tip of the tongue and elevates the base.

=Cerato-glossus.= Location.—On the upper portion of the cornu of the hyoid.

Origin.—One-half of the surface of the first basi-branchial.

Insertion.—To the upper side of the shaft of the cerato-branchial element of the hyoid apparatus.

Shape.—A small muscular fasciculus.

Relations.—Supero-laterally to the cerato-branchial element.

Action.—Elevates the cornua of the hyoid arches and presses them against the skull.

=Hyoideus Transversus= (Fig. 9, No. 9 and 10). Location.—Envelops the spur process of the euro-hyal.

Origin and Insertion.—It extends from the inner side of one cornu to the spur process.

Shape.—Thin, flat.

Relations.—Posterior to the euro-hyal, which it envelops, and between the cornua of the os hyoides.

Action.—Approximates the cornua of the os hyoides.

THE CERVICAL MUSCLES

Complexus Rectus capitis anticus minor Flexor capitis inferior Rectus capitis posticus major Biventer cervicis Longus colli posticus Obliquus colli Longus colli anterior Rectus capitis lateralis Trachelo-mastoideus Interspinales Interarticulares Obliquo-transversales Intertransversales Scalenus medius

=Complexus= (Fig. 19, No. 5). Location.—Supero-lateral portion of the neck.

Origin.—By three tendinous slips from the antero-lateral portion of the transverse process of the fourth, the fifth, and the sixth cervical vertebræ.

Insertion.—The muscular fibers pass around the neck and meet their fellows in the median line in a fascia formation. The thin tendinous sheet inserts into the occiput just above the occipital ridge.

Shape.—From point of origin this muscle expands into a broad sheet.

Relations.—It overlies the muscles of the occipital region.

Action.—It extends the head.

=Rectus Capitis Anticus Minor= (Fig. 19, No. 8). (Synonym.—Rectus capitis ventralis minor.)

Location.—Infero-lateral portion of the neck.

Origin.—From the apices of the hyapophyses of the second, the third, and the fourth cervical vertebræ.

Insertion.—To the occiput just below the complexus.

Shape.—A long and rather thick fasciculus.

Relations.—Externally with the skin. The tendinous slips of origin pass between the flexor capitis inferior and longus colli anterior.

Action.—Extends the head.

=Flexor Capitis Inferior= (Fig. 19, No. 7). Location.—Antero-inferior part of the neck.