Tongue Reconstruction

How much of the tongue lies within the oral cavity?

The anterior two-thirds of the tongue. The posterior limit of the oral cavity superiorly is the junction of the hard and soft palates and inferiorly the sulcus terminalis of the tongue.

What are other terms for the posterior third of the tongue?

The pharyngeal tongue or tongue base.

Where are the circumvallate papillae and the fungiform papillae located?

The circumvallate papillae lie immediately anterior to the sulcus terminalis. The fungiform papillae are scattered on the upper surface of the tongue anterior to the circumvallate papillae.

What separates the oral and pharyngeal portions of the tongue?

The sulcus terminalis.

Where on the tongue is the foramen cecum?

The apex of the sulcus terminalis.

Which structure migrates through the foramen cecum of the tongue during embryological development?

The thyroid.

Which embryological structures fuse to form the tongue?

The median tongue bud (tuberculum impar) and two distal tongue buds form the oral tongue. The hypobranchial eminence becomes the pharyngeal tongue.

Describe the surface anatomy of the tongue.

The oral tongue has an apex, which touches the incisors, a dorsum (the upper surface), and a smooth ventral surface, which is contiguous with the oral floor and gingiva. The tongue base is more vertical in orientation and contiguous with the glossoepiglottic folds.

What nerves provide general sensation to the tongue?

Oral: lingual nerve. Pharyngeal: glossopharyngeal nerve.

Which cranial nerves transmit taste sensation?

Cranial nerves (CN) VII, IX, and X; all contain special sensory taste afferent fibers.

What is the course of the chorda tympani nerve?

Taste fibers leave the lingual nerve and are conveyed via the chorda tympani. It carries taste sensory fibers from the anterior two-thirds of the tongue to the intratemporal facial nerve. With the lingual nerve, the chorda tympani travels from the ventral surface of the tongue to the lingual sulcus, where it is caudal to the submandibular duct; then superiorly, to the lingual border of the mandible near the third molar. The chorda tympani leaves the lingual nerve at the medial border of the lateral pterygoid and traverses the middle ear, joining CN VII in the facial canal.

Where are taste buds located?

Tongue, soft palate, palatoglossal arches, posterior surface of the epiglottis (CN X), and posterior oropharynx.

How many taste buds are there on each papilla?

Approximately 3, 250 and 1,200 taste buds are found on the fungiform, vallate, and foliate papillae, respectively. Filiform papillae have no taste buds.

What are the four types of taste?

Salty, sweet, sour, and bitter.

Where on the tongue is salty taste sensed?

The entire tongue surface can sense salty taste. There is a strong misconception that there is a “taste map.” In fact every taste can be sensed in all regions of the tongue.

What other sensation is important in recognizing flavors?

Olfaction. Patients who cannot smell may complain of lack of taste sensation.

Describe the musculature of the tongue.

The musculature of the tongue is divided into two functional halves by a fibrous septum. The extrinsic muscles, styloglossus, hyoglossus, and genioglossus together control the position of the tongue. They connect the tongue to the hyoid, mandible, and styloid processes. The palatoglossus assists in tongue elevation but is usually considered primarily to be a muscle of the palate. The intrinsic muscles shape the tongue by controlled contractions of transverse, longitudinal, and vertical fibers either side of the midline septum.

What provides motor supply to the muscles of the tongue?

The hypoglossal nerve.

What is the function of the genioglossus muscle?

The anterior fibers of genioglossus retract the tongue tip. The bulk action of genioglossus is to protrude the tongue anteriorly and inferiorly.

What is the blood supply of the tongue?

The lingual artery, arising from the external carotid artery, provides inflow. Drainage is via venae comitantes into the internal jugular vein.

What is the lymphatic drainage of the tongue?

The oral tongue lymphatics drain into the respective cervical nodal basin bilaterally. The level II nodes are most commonly affected by tongue cancer metastases, but levels I and III are also at high risk. Hence, the most commonly performed elective neck dissection for tongue cancer is a selective neck dissection of levels I, II, and III (also referred to as a supraomohyoid neck dissection).

What are the most important functions of the tongue?

Airway protection, swallowing (deglutition), tasting, articulating speech, and tongue finger function. Additionally, the tongue assists chewing by repeatedly presenting the food bolus to the teeth.

What use is the “finger function” of the tongue?

The ability of the tongue to form a firm tip that is useful for clearing the oral sulci, manipulating a food bolus, and cleaning the lips and dentition.

What are the phases of swallowing?

There are voluntary and involuntary phases of swallowing. First, in the voluntary (oral) phase of swallowing, the apex of the tongue is pressed against the palate. The intrinsic muscles move food posteriorly into the oropharynx by elevating sequential portions of the tongue to the palate. The tongue base is positioned superiorly and posteriorly, forming a food platform in readiness for the involuntary phase. Concurrently the hyoid bone is moved superiorly.

During the involuntary (pharyngeal), phase the palatopharyngeal sphincter seals the nasopharynx, while the larynx and pharynx are elevated. The tongue base and pharyngeal constrictors force the food bolus inferiorly over the posteriorly arched epiglottis and closed laryngeal inlet.

What is the most common tongue malignancy?