Anatomy
Head and Neck
Regarding the teeth, which of the following statements is CORRECT:
Answer:
In adults, there are 32 teeth, 16 in the upper jaw and 16 in the lower jaw. On each side in both upper and lower arches, there are two incisors, one canine, two premolars and three molar teeth.Teeth
Anatomy / Head and Neck / Mouth and Hard Palate
Last Updated: 11th April 2019
The teeth are attached to sockets in the upper alveolar arch on the maxilla and the lower alveolar arch on the mandible. The gingivae are specialised regions of oral mucosa that surround the teeth and cover adjacent regions of the alveolar bone.
Normal Dentition
In adults, there are 32 teeth, 16 in the upper jaw and 16 in the lower jaw. On each side in both upper and lower arches, there are two incisors, one canine, two premolars and three molar teeth. Two successive sets of teeth develop in humans; deciduous teeth emerging between six months and two years of age, and permanent teeth, which begin to emerge and replace the deciduous teeth at around age six years.
![Henry Vandyke Carter [Public domain], via Wikimedia Commons](https://mrcemsuccess.com/wp-content/uploads/2016/07/teeth.png)
Normal Dentition. (Image by Henry Vandyke Carter [Public domain], via Wikimedia Commons)
Innervation
All nerves that innervate the teeth and gingiva are branches of the trigeminal nerve. The lower teeth are innervated by the inferior alveolar nerve (branch of the mandibular nerve). The upper teeth are innervated by the anterior, middle and posterior superior alveolar nerves (branches of the maxillary nerve).
Anaesthesia of the inferior alveolar nerve can be performed by placing the needle lateral to the anterior arch of the fauces (palatoglossal arch) in the oral cavity and advancing along the medial border around the inferior third of the ramus of the mandible. It is also possible to anaesthetise the infraorbital and buccal nerves.
Tooth Structure
The portion of the tooth exposed to the oral cavity is the dental crown, and the portion below the dental crown is the tooth root. The dental pulp cavity exists in the centre of the tooth containing the pulp which consist of blood vessels, lymph vessels and nerve fibres.
![By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. (Own work) [CC BY 3.0], via Wikimedia Commons](https://mrcemsuccess.com/wp-content/uploads/2016/07/tooth-1024x1024.png)
Structure of a Tooth. (Image by Blausen.com staff. “Blausen gallery 2014”. Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. (Own work) [CC BY 3.0], via Wikimedia Commons)
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
