The bony surface of the roof of the mouth is perforated by numerous small foramina for the transmission of the nutrient vessels to the body of the bone, pitted for the lodgment of mucous glands, and grooved longitudinally for the transit of vessels. At the postero-external corners the posterior and accessory palatine canals give entrance to the posterior palatine vessels, and nerves; and anteriorly in the median line is the anterior palatine canal transmitting the naso-palatine vessels and nerves. The soft palate is a moveable curtain, consisting of a membranous expansion or aponeurosis attached to the posterior extremity of the hard palate by firm fibrous tissue. Incorporated with it are five pairs of muscles, controlling its movements; it is covered by a smooth thin mucous membrane, and terminates posteriorly in the uvula. The arrangement of these muscles is important, not only from their normal physiological functions, but also from their irregular action and effects in cases of cleft palate (Fig. 28). They may be arranged in groups: two, the levator and tensor palati, form a superior group; the azygos uvulæ is intermediate; and the palato-glossus and palato-pharyngeus form an inferior set. Arising from the extremity of the petrous bone, the levator passes downwards, and spreading out below unites with its fellow in the whole length of the median raphe. The tensor arises from the navicular fossa of the internal pterygoid plate, and after being reflected around the hamular process, its action there being assisted by the interposition of a bursa, is attached to the anterior portion of the aponeurosis and to the hinder part of the bony palate. The combined action of these muscles raises and makes tense the velum, and in addition influences the Eustachian tube; but the levator is by far the more important. The azygoi uvulæ muscles arising from the median raphe and spine of the hard palate descend to the tip of that process, and are thus able to regulate its length. [Illustration: FIG. 28.—Muscles of palate dissected. The cut represents the posterior nares and upper surface of the soft palate. _a._ The levator palati. _b._ The inner bundle of fibres of the palato-pharyngeus, forming the posterior pillar of the fauces, _c._ The palato-glossus. _d._ The tensor palati; the cartilaginous extremity of the Eustachian tube is seen in front of this latter. _e._ The posterior extremity of the inferior turbinated bone. _f._ The septum. _g g._ The uvula on each side stretched apart. (_Fergusson._)]