Helictites are, perhaps, the most delicate of cave formations. They are usually made of needle-form calcite and aragonite. Forms of helictites have been described in several types: ribbon helictites, saws, rods, butterflies, hands, curly-fries, and clumps of worms.. They typically have radial symmetry.
The temporomandibular joint (TMJ) is the joint where the mandible articulates with the cranium (Fig 8.1). The following characteristics make the TMJ a complex and unique joint: 1  It is classified as a compound joint even though it does not include three bone structures in the articulation.
Some authorities also include the maxilla, zygomatic bone, and palatine bone. See anatomic Table of Bones in the Appendices. ethmoid bone the sievelike bone that forms a roof for the nasal fossae and part of the floor of the anterior cranial fossa. See anatomic Table of Bones in the Appendices. facial b's the bones that form the skeleton of the face, including the hyoid, palatine, and zygomatic bones, the mandible, and the maxilla. Some authorities include the lacrimal bones, nasal bones, inferior nasal concha, and vomer and exclude the hyoid bone. See anatomic Table of Bones in the Appendices.