The medial aspect of the spine provides attachment for the most lateral part of the tensor veli palatini muscle of the soft palate.
The styloid process and inferior aspect of the petrous part of the temporal bone provide attachment for muscles associated with the tongue and soft palate, respectively.
The styloid process projects anteroinferiorly from the underside of the temporal bone. It can be as long as 1 inch (2.5 cm) and points toward the lesser horn of the hyoid bone to which it is attached by the stylohyoid ligament (Fig. 8.248B). The root of the styloid process is immediately anterior to the stylomastoid foramen and lateral to the jugular foramen. The styloglossus muscle of the tongue attaches to the anterolateral surface of the styloid process.
The inferior aspect of the temporal bone has a triangular roughened area immediately anteromedial to the opening of the carotid canal (Fig. 8.248A). The levator veli palatini muscle of the soft palate is attached here.
Cartilaginous part of the pharyngotympanic tube
The trumpet-shaped cartilaginous part of the pharyngotympanic tube is in a groove between the anterior margin of the petrous part of the temporal bone and the posterior margin of the greater wing of the sphenoid (Fig. 8.248A).
The medial and lateral walls of the cartilaginous part of the pharyngotympanic tube are formed mainly of cartilage, whereas the more inferolateral wall is more fibrous and is known as the membranous lamina.
The apex of the cartilaginous part of the pharyngotympanic tube connects laterally to the opening of the bony part in the temporal bone.
The expanded medial end of the cartilaginous part of the pharyngotympanic tube is immediately posterior to the upper margin of the medial plate of the pterygoid process and opens into the nasopharynx.
The cartilaginous part of the pharyngotympanic tube is lateral to the attachment of the levator veli palatini muscle and medial to the spine of the sphenoid. The tensor veli palatini muscle is attached, in part, to the membranous lamina.
The mandible is the bone of the lower jaw (Fig. 8.249). It consists of a body of right and left parts, which are fused anteriorly in the midline (mandibular symphysis), and two rami. The site of fusion is particularly visible on the external surface of the bone as a small vertical ridge in the midline.
The upper surface of the body of the mandible bears the alveolar arch (Fig. 8.249B), which anchors the lower teeth, and on its external surface on each side is a small mental foramen (Fig. 8.249B).
Posterior to the mandibular symphysis on the internal surface of the mandible are two pairs of small spines, one pair immediately above the other pair. These are the superior and inferior mental spines (superior and inferior genial spines) (Fig. 8.249A,C), and are attachment sites for a pair of muscles that pass into the tongue and a pair of muscles that connect the mandible to the hyoid bone.
Extending from the midline and originating inferior to the mental spines is a raised line or ridge (the mylohyoid line) (Fig. 8.249C), which runs posteriorly and superiorly along the internal surface of each side of the body of the mandible to end just below the level of the last molar tooth.
Above the anterior one-third of the mylohyoid line is a shallow depression (the sublingual fossa) (Fig. 8.249C), and below the posterior two-thirds of the mylohyoid line is another depression (the submandibular fossa) (Fig. 8.249C).
Between the last molar tooth and the mylohyoid line is a shallow groove for the lingual nerve.