Head and neck anatomy
Head and neck anatomy is a specialized study of the human body quite frequently studied in depth by surgeons, dentist, and dental technicians. This branch of study focuses on the
bones,
muscles,
circulatory system, nerves, glands, and nose, mouth, teeth, tongue, and throat structures.
Dental students focus their studies on teeth and the support structures of teeth. However, there are no independent structures or systems of the body. An
abcessed tooth may quickly spread
pathogens to other body organs and systems. For example an infected tooth may lead to heart disease (
Endocarditis) and kidney disease (
Glomerulonephritis) if the pathogen is either a
staphylococcus aureus (staph) or
streptococcal (strep) bacterium.
Musculoskeletal anatomy
The
head is positioned upon the superior portion of the
vertebral column, attaching the skull upon the
atlas (anatomy). The skeletal section of the head and neck forms the superior segment of the axial skeleton and is comprised of
skull,
hyoid bone and
cervicle spine. The skull can be further subdivided into (1)
cranium and (2)
facial bones. The
occipital skull bone articulates with the atlas at the
foramen magnum. The atlas articulates with the occipital condyle superiorly and the axis inferiorly. The spinal cord passes through the foramen magnum . Articulations of the neck include: flexion, extension, hyperextension (nodding yes), and rotation (shaking head no).
Oral Cavity
The
mouth, (oral cavity) is the entranceway into the
digestive system containing both primary and accessory organs of digestion. The mouth is designed to support chewing, (mastication) and swallowing, (deglutition), and speech. Two rows of teeth are supported by facial bones of the skull, the
maxilla above and the
mandible below.
Teeth
Humans normally will produce two sets of teeth called primary dentition, (or
deciduous teeth) and secondary dentition or
permanent teeth .
A
tooth is the toughest known substance in the body exceeding bones in density and strength.
Tooth enamel lends great strength to the tooth structure, the formation of a developing tooth includes the process of inserting enamel on the
dentin, (see:
Dentinogenesis) layer as the tooth breaks through the gum line is called
amelogenesis. The formation of teeth begins in early fetal development and goes through four stages: (1) bud stage, (2) cap stage, (3) bell stage, and (4) crown, or calcification, stage. Tooth enamel is white initially but is susceptible to stains from coffee and cigarette usage. A tooth sits in a specialized socket called
gomphosis. The tooth is held in location by a
periodontal ligament.
The white visable part of a tooth is called the
crown. The rounded upper projections of the back teeth are
cusps. The hard white exterior covering of the tooth is the
enamel. As the tooth tapers below the gumline, the
neck is formed. Below the neck, holding the tooth into the bone, is the
root of the tooth. The inner portions of the tooth consist of the dentin, a bonelike tissue, and the
pulp. The pulp is a soft tissue area containing the nerve and blood vessels to nourish and protect the tooth.
There are various tooth shapes for different jobs. For example, when chewing, the upper teeth work together with the lower teeth of the same shape to bite, chew, and tear food. The names of these teeth are: (1)
Incisors, there are eight incisors located in the front of the mouth (four on the top and four on the bottom). They have sharp, chisel-shaped crowns that
cut food. (2) Cuspids. or
canine tooth, the four cuspids are next to each incisor. Cuspids have a pointed edge to
tear food. (3)
Premolars or (bicuspids), the four pairs of molars are located next to the cuspids. They
crush and
tear food. And, (4)
Molars, there are twelve molars, in sets of three, at the back of the mouth. They have wide surfaces that help to
grind food. Adults have 32 permanent teeth, and children have 24 deciduous teeth.
Salivary Glands
There are three sets of
salivary glands: the parotid, the submandibular and the sublingual glands. The (
exocrine) glands secrete saliva for proper mixing of food and provides enzymes to start chemical digestion.
Saliva also helps to hold together the formed
bolus which is swallowed after chewing.
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1]
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2]
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ADHA Dental Hygene*
Tooth*
Anatomy*
Throat,pharynx
*
Ear*
Mouth*
Core Curriculum Syllabus: Review of Anatomy*
Core Curriculum Syllabus: Review of Anatomy - Temporal Bone and Ear*
Dental anatomy, CSU*
Head and Neck Anatomy*
Neuroscience for Kids*
American Dental Hygienists Association, Website
