Lip Reconstruction

What is the function of the lips?

Establishment of oral competence (function of orbicularis oris muscle), modulation of the spoken word, facial expression, as well as a role in social relationships.

What is cheiloscopy?

The study of lip prints. Lip prints have a unique topographic pattern, just like a fingerprint pattern.

What are the critical and unique anatomic landmarks of the lip?

Philtral columns, philtral groove, Cupid’s bow and tubercle for the upper lip; the vermilion (white roll or mucocutaneous junction); and oral commissures.

Where is Cupid’s bow located?

Found on the upper lip, Cupid’s bow is the area of vermilion border at the base of the two philtral columns.

When do the lips begin to develop embryologically?

At 4 to 5 weeks of gestation.

What are the important processes that occur during embryologic development of the lips?

The two medial nasal prominences fuse with the maxillary prominences to form the upper lip. The mandibular prominence contributes to lower lip development. Failure of neural crest cell migration (as early as day 22) results in variable clefting of the upper lip.

Discuss the perioral subunit principle of the lips.

Burget and Menick described the lateral subunit, bordered by the philtral column, nasal sill, alar base and nasolabial fold, as well as the medial subunit, which represents one-half of the philtrum.

What is the subunit principle?

When the majority of a subunit has been lost, replacement of the entire subunit with like tissue yields the best aesthetic reconstruction.

What is the blood supply to the lip?

Is derived from the facial artery, branching into both the inferior and superior labial artery.

What muscle planes does the facial artery travel within?

Deep to the platysma, risorius, and zygomaticus major and minor muscles and superficial to the buccinator and levator anguli oris.

Where does the inferior labial artery branch from the facial artery?

2.6 cm lateral and 1.5 cm inferior to the oral commissure.

The facial artery terminates into what artery in the midface?

It becomes the angular artery, forming branches to the nasal ala and anastomosing with the dorsal nasal artery. The facial and labial arteries communicate with the subdermal plexus through a dense population of musculocutaneous perforators.

What is the lymphatic drainage pattern of the lips?

The upper lip and lateral lower lip drain primarily to the submandibular lymph nodes. The remaining lower lip drains to the submental nodes.

What is the motor innervation to the lips?

The facial nerve, whose buccal and marginal mandibular branches supply the perioral musculature on their undersurface.

What muscles of facial expression are innervated on their superficial surface?

The buccinator, levator anguli oris, and mentalis.

What is the sensory innervation to the lips? What innervates the upper lip?

Maxillary and mandibular divisions of the fifth cranial nerve. The infraorbital nerve, which is a terminal branch of the maxillary nerve, innervates the upper lip. The lower lip and chin receive sensory innervation from branches of the mandibular nerve (mental nerve).

Where does the inferior alveolar nerve travel?

The inferior alveolar nerve, a branch of the mandibular nerve, travels through the body of the mandible and exits from the mental foramen.

What landmarks are used for an infraorbital nerve block?

The nerve exits the infraorbital foramen 4 to 7 mm below the inferior orbital rim on a vertical line that descends from the medal limbus of the iris.

What is the course of the infraorbital nerve and what does it supply?

It travels beneath the levator labii superioris and superficial to the levator anguli oris to supply the lateral nasal sidewall, ala, columella, medial cheek, and upper lip.

What landmarks are used to find the mental foramen?

It is located below the apex of the second mandibular bicuspid but has 6 to 10 mm of lateral variability.

What territory does the mental nerve supply?

The lower lip skin down to the labiomental fold. The nerve is located in the submucosa as it exits the foramen and frequently is visible in this location.

What are the steps for performing a mental nerve block?

The lower lip is pulled out, and with tension, the mental nerve can be visualized on stretch in the mucosa on each side. It is just lateral to the canine, using this technique. It is injected with local anesthetic in the mucosa, and not at the mental foramen.

Which nerve block anesthetizes the central chin?

Inferior alveolar nerve block.

What are the goals of lip reconstruction?

Reconstruction of skin and oral mucosa, re-establishment of the vermilion, maintenance of an adequate stomal diameter, maintenance of sensation, and to restore normal oral sphincter function (competence).

What are the limits of primary closure of the lower lip in terms of tissue loss? What about the upper lip?

Up to one-third of lower lip loss may be tolerated with primary closure before microstomia and oral incompetence become a concern. Up to 25% tissue loss of the upper lip allows for reasonable primary closure.

What is the minimal functional diameter of the oral stoma?