There are three extensions: first, the _processus intermaxillaris_, which forms the upper wall of the nasal cavity; second, the _processus maxillaris anterior_, directed downward and forward, which fuses with the maxillary bone and forms the posterior rim of the nasal cavity; and third, a _posterior processus frontalis_, which lies parallel with the ethmoid. =The Lacrimal.= _Location._—The lacrimal bones, or ossa lacrimalia, two in number, are located at the outer border and at the junction of the processus frontalis of the nasal, with the frontal bone. _Description._—The lacrimal bone is small, and rather filiform. They become fused with the nasal and the frontal bones, forming part of the margin of each. =The Palatine.=—_Location._ The palatine bones, or ossa palatina, two in number, enter into the formation of the inner part of the bony gum and hard palate, or roof of the mouth. They form the support for the hard palate. Each palatine articulates posteriorly with the rostrum, or nasal portion of the sphenoid, and with the pterygoid; and anteriorly with the maxilla. _Description._—The palatine bone is curled posteriorly and is thin at the upper portion and thick at the lower border. Anteriorly it has a long rather filiform projection. =The Pterygoid.= _Location._—The pterygoid bones, or ossa pterygoidea, two in number, are located back of the region of the posterior nares. They extend diagonally outward and backward from the median region of the sphenoid rostrum to the quadrate bone. They articulate anteriorly with the sphenoid rostrum and the palatine, and posteriorly with the quadrate. _Description._—The pterygoid bones are slender and cylindrical, and are expanded at the ends into an articular facet. =The Zygomatic.= _Location._—The zygomatic, or ossa zygomatica, two in number are situated below the orbital cavity and extend from the maxilla to the quadrate bone. _Description._—The zygomatic is small, slender, rod-shaped, and forms the lateral portion of the upper jaw. The anterior portion of the zygomatic represents the jugal and is fused with the maxilla and with the anterior processus maxillaris of the nasal bone, the maxilla, and the posterior portion, the quadrato-jugal, which articulates with the quadrate bone. =The Vomer.= _Location._—The vomer is located in the median nasal septum. It articulates with the rostrum of the sphenoid, being connected to it by a mass of ligaments. It touches anteriorly the posterior portion of the maxilla. _Description._—The vomer is a median bone and aids in the formation of the septum nasi. It consists of a thin plate, thickest posteriorly and diminishing toward the anterior edge. =The Jugal and Quadrato-jugal.=—The jugal and quadrato-jugal are united forming a long slender cylindrical bone called the zygomatic, lying at the outer side of the upper jaw. They have been described under zygomatic, which see.