The structure of Lips, it’s parts and all the structures

lips, soft pliable anatomical structures that form the mouth margin of most vertebrates, composed of a surface epidermis (skin), connective tissue, and (in typical mammals) a muscle layer.

In man the outer skin contains hair, sweat glands, and sebaceous (oil) glands. The edges of the lips are covered with reddish skin, sometimes called the vermilion border, and abundantly provided with sensitive nerve endings. The reddish skin is a transition layer between the outer, hair-bearing tissue and the inner mucous membrane. The interior surface of the lips is lined with a moist mucous membrane. In newborn infants the inner surface is much thicker, with sebaceous glands and minute projections called papillae. These structural adaptations seem to aid the process of sucking. Most of the substance of each lip is supplied by the orbicularis oris muscle, which encircles the opening. This muscle and others that radiate out into the cheeks make possible the lips’ many variations in shape and expression.

Diseases that particularly affect the lips include herpes simplex (fever blisters, or cold sores) and leukoplakia (white patches, which may be precancerous). In elderly men, ulcers on the vermilion border of the lower lip are frequently cancerous. The borders also may become cracked and inflamed from excessive drying by the weather, chemical irritants, inadequate moistening because of infection, or in reaction to antibiotics.

1. LIP PRESENTED BY , Aishwaria babu MSC .First year DSD

2. TOPICS - Structure - Muscle

3. Difference between nasolabial folds and marionette lines

4. STRUCTURE Differences ---------------------------------------------------------

5. The lips are two mobile musculofibrous folds that surround opening of mouth. The upper and lower lips meet laterally at an angle of the mouth , usually in front of first premolar tooth. The lips are lined externally by the skin and internally by mucous membrane . The mucocutaneous junction lines the edge of the lip . only a part of the mucosal surface is normally seen . The red portion of lip is called vermillion zone , the red hue is due to rich vascular bed visible through thin moist epithelium . The skin and vermillion zone meet at the vermillion border. The internal aspect of each lip is connected to the corresponding gum by a median fold of the mucus membrane called frenulum of lip . A cupid ‘s bow that consists of two convex curve usually with recurved ends. T he upper lip has a depression at its center, directly under the nasal septum, called the philtrum. At the extremity of the philtrum is a small elevation called the tubercle. The upper lip has a depression at its center, directly under the nasal septum, called the philtrum.

6. LIP MUSCLES 1. ORBICULARIS ORIS 2.Levator labii superioris alaeque nasi(LLSAN) 3.Levator labii superioris 4.Levator anguli oris 5.Zygomaticus minor 6.zygomaticus major 7.Depressor labii inferioris 8.Depressor anguli oris 9.Risorius 10.MENTALIS 10.Buccinator 11.PLATYSMA

7. Orbicularis oris(Kissing muscle)

8. ORIGIN INSERTION FUNCTION Modiolus Skin and mucous membrane of lips Act like a constrictor Sphincteric action of mouth Production of speech sounds Swallowing Mastication Sucking Puckering

9. ORBICULARIS ORIS

10. Levator labii superioris Origin :   Its origin is on the lateral aspect of the nose, and it extends laterally towards the zygomatic bone .

11. Function :  Lip elevation Insertion :  Upper lip’s skin between the levator anguli oris and the levator labii superioris alaeque nasi(LLSAN)

12. Levator labii superioris alaeque nasi (LLSAN) Origin :   Frontal process of maxilla ------------------------ Insertion : Ala of nose by one slip and to the upper lip by another slip   Function: Lip elevation

13. Levator anguli oris Origin:  From maxilla below the infraorbital foramen -------------------------------------------- Insertion: modiolus Function: Lip elevation  

14. Zygomaticus minor and Zygomaticus major : Muscle Origin Insertion Function Zygomaticus minor Zygomatic bone Upper lip Elevates the upper lip Zygomaticus major Angle of mouth Draws angle of mouth upward and laterally

15. Depressor labii inferioris Depressor anguli oris

16. Muscle Origin Insertion Function Depressor labii inferioris Anterior oblique line of the mandible Lower lip Lip depression Depressor anguli oris Posterior part of oblique line of mandible Angle of mouth

17. Risorius(smiling muscle) -------------------------------- Origin Insertion Function Fascia of lateral cheek over parotid gland and superficial masseter and platysma muscle Modiolus Pulling the corner of mouth laterally

18. Mentalis -------------------------------------------------- Origin Insertion Function Incisive fossa of mandible Skin of lower lip Puckers the chin and protrudes the lower lip Incisive fossa

19. Buccinator(Buglers muscle/TRUMPETER’S MUSCLE Origin : Superior part: Alveolar process of maxilla Inferior part: Alveolar part of mandible Posterior part: Pterygomandibular raphe, buccinator crest of mandible ------------------------------------------------- Buccinator crest Pterygomandibular raphe

20. Function: Compresses cheek against molar teeth

21. Platysma Origin: F ibers arising from the fascia of the upper thorax including the clavicle, acromial region, pectoralis major and deltoid muscles . Insertion: T he muscle inserts on the mandible, the cheek skin, the commissure of the mouth, the orbicularis oris muscle, to the posterior border of the depressor anguli oris muscle, and in some cases higher as high as the orbicularis oculi muscle. Function: elevation of the neck Pulling the corners of the lips out to the side and down Opens the mouth

22. REFERENCES : T extbook of anatomy head , neck and brain ken hub Stat pearls BD Chaurasia

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