Here is a term paper on the ‘Mandible’. Find paragraphs, long and short term papers on the ‘Mandible’ especially written for school and college students.

Term Paper on the Mandible

Term Paper # 1. Anatomical Structure of Mandible:

It is the bone of lower jaw, develops from mesoderm of first pharyngeal arch. It is the thickest and strongest bone of the face. It takes part in the formation of temporo mandibular joint.

Parts:

ADVERTISEMENTS:

It has two parts:

I. Body and

II. Ramus.

I. Body of the Mandible:

ADVERTISEMENTS:

Two halves of the body meets in the midline and form symphysis menti.

Body has two surfaces – external and internal surface.

Two borders:

a. Alveolar border or superior border.

ADVERTISEMENTS:

b. Base or inferior border.

Term Paper # 2. External Surface of Mandible:

Shows following features:

1. Mental Foramen:

ADVERTISEMENTS:

Lies in between upper and lower borders at the level of second premolar tooth, directed upwards and backwards. Mental nerve and vessels passes through this foramen.

In old age due to wear and tear of the alveolar – border, mental foramen moves upwards.

2. Symphysis Menti:

It is the line of fussion of two halves of the foetal mandible, seen as a faint ridge on the upper part of the body in the midline.

ADVERTISEMENTS:

3. Mental Protuberance:

Lies below the symphysis menti, in the form of a triangular prominence, forms chin lateral to the protuberance an elevation called mental tubercle is present.

4. External Oblique Line:

It extends from the mental tubercle, ill-defined anteriorly and well defined posteriorly. It joins anterior border of ramus posteriorly.

ADVERTISEMENTS:

5. Incissive Fossa:

It is a small depressed area below the incisor teeth.

Attachments on the External Surface of Body:

1. Incissive fossa gives origin to mentalis muscle and deepest part of the orbicularis oris.

2. Oblique line gives origin to depressor labii inferioris, depressor anguli oris and buccinator muscle from anterior to posterior.

3. The lower border or base gives insertion to platysma and investing layer of deep fascia neck is attached to it.

4. Mental vessels and nerve are emerging out from the mental foramen onto the face.

Term Paper # 3. Internal Surface of Body of Mandible:

Features are:

1. Genial Tubercles:

A pair of tubercles is present in the midline of mandible internally. They are a pair of superior genial tubercles and a pair of inferior genial tubercles.

2. Mylohyoid Line:

Begins below the third molar tooth. It is oblique, runs forwards and fades away near the anterior end. It divides the inner surface into two areas. Upper one is the sublingual fossa and lower one is submandibular fossa.

3. Mylohyoid Groove:

It lies below the posterior end of mylohyoid line.

Characteristic Features:

1. Superior genial tubercles give origin to genioglossus muscle.

2. Inferior genial tubercle gives origin to geniohy­oid.

3. Submandibular fossa lodges submandibular salivary gland, submandibular lymph nodes and facial artery.

4. Mylohyoid line gives attachment to deep cervi­cal fascia and mylohyoid muscles arises from it.

5. Sublingual fossa lodges – sublingual salivary gland.

6. Lingual nerve makes a groove just below the third molar tooth.

7. The pterygo mandibular raphe is attached behind the posterior end of mylohyoid line. It also gives origin to superior constrictor muscle of pharynx.

8. Mylohyoid groove lodges nerve and artery to mylohyoid muscle.

9. Alveolar border has sockets for the teeth of the lower jaw and lodging them.

Lower Border of the Mandible:

It is thick and round, shows:

1. Digastric fossa- It is a shallow depression lies lateral to the midline. Anterior belly of digastric muscle originate from it.

2. Platysma inserted on the lower border and investing layer of deep cervical fascia is attached to it.

II. Ramus of the Mandible:

It is quadrangular shaped, lying posteriorly. All muscles of mastication are attached to it. Ramus has four borders and two surfaces.

Borders are:

1. Anterior Border:

This is sharp and continuous with the anterior border of coronoid process. On this border temporalis muscle is inserted.

2. Posterior Border:

This is thicker, superiorly it is continued as condyloid process, and inferiorly it forms the angle of mandible by joining with the inferior border. On this border stylomandi­bular ligament is attached, which is formed by the thickening in the deep cervical fascia.

3. Superior Border:

It is concave and sharp, forms mandibular notch. Through the notch masseteric nerve and vessels are passing. Coronoid and condyloid processes are projecting upwards from this border.

4. Inferior Border:

Is blunt, posteriorly it forms angle of mandible by joining with posterior border; anteriorly it is continuous with the base of mandible. It is related to facial artery and vein. Marginal mandibular branch of facial nerve runs along this border.

Lateral Surface of Ramus:

Is rough gives insertion to masseter muscle.

Medial Surface of Ramus:

Features are:

i. Mandibular Foramen:

Situated in the middle of medial surface, it leads to the mandibular canal. From the medial margin of this foramen a sharp process projects upwards – called lingula. It gives attachment to sphenomandibular ligament. Foramen transmits inferior alveolar nerve and vessels.

ii. Mylohyoid Groove:

It is a linear groove commences below the mandibular foramen and lodges mylohyoid nerve and vessels.

iii. Inner surface of ramus anterior to the angle is rough and gives insertion to medial pterygoid muscle.

Processes of mandible are coronoid and condyloid process – projecting upwards from ramus.

1. Coronoid Process:

It is sharp and pointed, triangular in shape, lies anterior to mandibular notch. It gives insertion to temporalis muscle.

2. Condyloid Process:

Upward continuation of upper border of ramus, forms posterior boundary of mandibular notch. The upper end of the process is the head of the mandible, which articulates with the mandibular fossa of temporal bone and forms T.M J. below the head and neck of mandible is situated, gives attachment to capsular ligament of the joint.

On the anterior surface of the neck, a pit or depression lies called pterygoid fovea gives insertion to lateral pterygoid muscle. The lateral surface of the neck gives attachment to temporomandibular liga­ment (lateral ligament). Medial surface of the neck is related to maxillary artery and auriculo temporal nerve.

The head of the mandible is broader transversely. The lateral aspect of head shows a rounded tubercle.

Mandibular Canal:

Found within the mandible. It extends between mandibular foramen and mental foramen. Terminally it divides into mental and incissive canals. Inferior alveolar nerve and vessels are passing through it.

Ossification:

It is the second bone to ossify in the body. It is formed from Meckel’s cartilage, later developed in membrane bone. Each half of the lower jaw is ossifies from a single centre, appears by the 6th neck of intra uterine life. The center appears on the membrane covering the anterior half of the Meckel’s cartilage, anterior to the mental foramen. The condyloid and a part of coronoid process are formed from the Meckel’s cartilage.