The mucous membrane (mucosa, tunica mucosae) forms the epithelial lining of the inner surface of the digestive tract (intestinal mucosa), oral and nasal cavity, airways, respiratory organs, and urinary and sexual organs.
The glands are organs made up of specialized cells of the epithelium that produce a specific substance: a secretory product. Glands that release their secretion through a separate secretory duct or directly to an external or internal surface are known as exocrine glands (exo = outside; krinein = secrete). These are distinguished from endocrine glands, which release their internal secretion (hormone) directly to the bloodstream. Glands can be classified according to the nature of their secretion:
The skin is flexible and elastic to permit tension-free movements, especially at the joints. Its secretions make it particularly resistant. Pigments contained in the germ layer determine the color of the skin. The skin adapts to the mechanical strain on the different areas of the body. The dermal ridges (a special marking on the surface of the skin) develop individually as a hereditary pattern in each person so that impressions of the pads of the fingers and toes as well as the balls of the feet and hands enable a person to be identified (dactyloscopy, ie, finger print analysis).
The skin (cutis) covers the outer surface of the body and, in an adult, is an organ measuring roughly 1.6 m2, with an average thickness of 1 to 4 mm. The veins can show as a bluish color through very thin areas of the skin. The skin is a contact organ, meaning that physical events and the environment can come into contact with it. The functions of the skin are outlined in the following paragraphs.
The articular capsule (capsula articularis) forms an airtight seal around the joint so that slight negative pressure can be created inside the joint cavi-ty.The negative pressure in the joint cavity means that the bony joint components are firmly pressed together. The joint capsule is attached around the mandibular fossa and is loose and wide enough to ensure that the movements of the joint cannot be impeded.
The articular disc (discus articularis), also known as the joint disc, is made up of tight connective tissue fibers in which fibrocartilage is embedded. It is a curved disc that is thickened at the edges; it is 1 to 1.5 mm thick in the middle and 3 to 4 mm thick at the edges. The articular disc is fused throughout to the joint capsule, so that it divides the joint into two compartments and makes it into a double joint.
The mandible as a single bone is fixed to the skull by two true (synovial) joints. The two joints are entirely separate from each other, but because they are identical in structure and because movement of the mandible always takes place simultaneously in both joints, they are often merely referred to as a single joint (articulatio temporo-mandibularis; Latin, articulatio = joint). Therefore, the topographic description can be applied to a single TMJ.
A distinction is made between joints (junctions or juncturae) and true joints (synovial joints or articulations) in terms of the way bones are joined together. Juncturae are the solid bony connections such as sutures (Fig 6-29), synchondroses (cartilaginous joints), and ossified connections. These are defined according to the nature of the connecting material:
The rami of the mandible (rami mandibulae; singular: ramus mandibulae) are the extensions of the mandibular body rising vertically in a dorsal direction.The constructive foundation is the basal arch, from which the functionally oriented parts such as the angle of the mandible and the condylar and coronoid processes arise (Figs 6-26 and 6-27).
The digastric fossa (fossa digastrica) is a flat depression on the inferior border of the mandibular body at the symphysis. It is the attachment point for the digastric muscle.