The two descending muscles are placed in the pillars of the fauces, forming the lateral prolongations of the velum, and the tonsils lie in a recess between them. The palato-glossi arising from the tongue ascend in the anterior pillars of the fauces, and spreading out on the anterior surface of the velum unite in the median raphe. The palato-pharyngei start from the median raphe in two lamellæ enclosing the termination of the levator muscle; they descend in the posterior pillars of the fauces, and being attached to the pharyngeal wall between the superior and middle constrictors, by their contraction assist in raising the pharynx during deglutition.

The nervous supply of these muscles requires little notice here; suffice it that the superior set and the azygos are supplied by the facial nerve, the inferior set from the pharyngeal plexus.

The mucous membrane of the hard palate is of the usual oral type, and only differs from that of the rest of the mouth in its close attachment to the periosteum, from which in fact it is almost impossible to separate it. It is thick, dense, rather pale and much corrugated, especially in front and at the sides, whilst behind over the velum it is smoother and thinner. In it are many small glands (palatine glands) which extend down to the periosteum. In the median line is a well-marked raphe, extending anteriorly to a prominence indicating the position of the anterior palatine canal. The rugose condition of the membrane over the hard palate is not seen in young children; it supervenes later in life.

The vascular supply of the palate is free and abundant, a circumstance which is of the greatest surgical importance in that it permits of the free detachment of the soft structures from the hard by long lateral incisions, and the necessary manipulation of these in uranoplastic operations without any fear of loss of vitality, provided that the patient’s health and constitution are tolerably sound, and that sufficient pedicle is left in front and behind.

The mucous membrane of the hard palate derives its blood supply from two of the terminal branches of the internal maxillary artery. The naso-palatine descend through the anterior palatine canal, and entering the palate at the incisive foramen (foramina of Stenson) assist in supplying the anterior portion, anastomosing with the terminations of the more important posterior or descending palatine, which find their way to the palate from the spheno-maxillary fossæ through the posterior palatine canals. Each of the latter arteries on reaching the palate sends branches to the velum and tonsils, and its main twig runs onwards in a groove of the bone to supply the mucous membrane and glands of the hard palate and gums. Its usual position is parallel to the alveolar border, and about three quarters of an inch from it; but this varies considerably. The artery can often be felt pulsating as it emerges from the bone, and is very likely to be divided in the lateral incisions made during the operation of uranoplasty; but the knife should be carried external to it, if possible, so that the trunk of the vessel may be preserved in the flap. The bony palate derives its blood supply not only from its lower surface but also from its upper, and hence detachment of the inferior periosteal covering does not lead to death of the bone. The soft palate derives its blood from three sources, viz. the ascending palatine of the facial, the ascending pharyngeal, and the posterior palatine of the internal maxillary. The two former reach it through the sinus of Morgagni, i. e. over the upper border of the superior constrictor muscle, forming loops of anastomosis on its posterior aspect with similar branches on the opposite side; the last supplies the anterior palatal surface.

The normal shape of the palate is a regular arch, bounded laterally by the gums and alveoli into which the teeth are implanted so as to describe a parabolic curve, being normally uninterrupted at any spot by spaces or diastemata. The height and curvature of the palate vary considerably in different individuals, not only from inherited peculiarities, but also from acquired conditions dependent on the teeth. A person with a good set of sound teeth will probably own a regular well-formed palate; whilst if sundry of the upper permanent teeth are lost during the stage of adolescence, the palate is likely to become high and narrow from the falling in of the jaw. This is especially the case if the incisor teeth are lost.

The shape of the palate in a child of two years does not differ so markedly as one would at first expect from that of an adult except in length, and the reason for this is plainly the existence in the latter of three additional teeth on each side. Its increase in length is from 20 to 30 millimetres, whilst its breadth is only augmented by 10 to 15 mm., and this mainly posteriorly. When once the permanent incisors, canines, and premolars are developed, the anterior portion of the palate alters but little in shape, unless any of these teeth be lost, and the gaps not artificially maintained.

Dr. Ehrmann[36] states that the alveolar border in front of the canine teeth forms a nearly regular semicircle, with a posterior transverse diameter of 22-26 mm.; thence the alveoli diverge regularly, adding to the diameter about 2-4 mm. for each tooth. He gives the following measurements as the mean of many observations:

From
2-6 yrs.		From
7-10 yrs.		From
11 yrs.
Interval between canines22-25 mm.23-27 mm.25-28 mm.
” 1st premolars24-29 ”25-30 ”27-30 ”
” 2nd ”26-31 ”28-32 ”31-34 ”
” 1st molars——32-37 ”

Oakley Coles[37] has carefully investigated the size of the palate in several series of skulls in the Museum of the College of Surgeons, and gives the results as follows: