| Infraorbital margin | |
|---|---|
 Skull, anterior view, with infraorbital margin labeled in red. | |
| Details | |
| Identifiers | |
| Latin | margo infraorbitalis |
| TA | A02.1.00.072 |
| FMA | 53177 |
| Anatomical terminology | |
The infraorbital margin is the lower margin of the eye socket.
| Infraorbital margin | |
|---|---|
| Skull, anterior view, with infraorbital margin labeled in red. | |
| Details | |
| Identifiers | |
| Latin | margo infraorbitalis |
| TA | A02.1.00.072 |
| FMA | 53177 |
| Anatomical terminology | |
The infraorbital margin is the lower margin of the eye socket.
It consists of the zygomatic bone and the maxilla, on which it separates the anterior and the orbital surface of the body of the maxilla.
In the human skull, the zygomatic bone is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is situated at the upper and lateral part of the face and forms the prominence of the cheek, part of the lateral wall and floor of the orbit, and parts of the temporal fossa and the infratemporal fossa. It presents a malar and a temporal surface; four processes, and four borders.
The maxilla in animals is the upper fixed bone of the jaw formed from the fusion of two maxillary bones. The upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible, which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.
It is an attachment for the levator labii superioris muscle.
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The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways.
The inferior nasal concha is one of the three paired nasal conchae in the nose. It extends horizontally along the lateral wall of the nasal cavity and consists of a lamina of spongy bone, curled upon itself like a scroll,. The inferior nasal conchae are considered a pair of facial bones. As the air passes through the turbinates, the air is churned against these mucosa-lined bones in order to receive warmth, moisture and cleansing. Superior to inferior nasal concha are the middle nasal concha and superior nasal concha which arise from the cranial portion of the skull. Hence, these two are considered as a part of the cranial bones.
The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or Zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species.
The gums or gingiva, consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
The levator labii superioris is a muscle of the human body used in facial expression. It is a broad sheet, the origin of which extends from the side of the nose to the zygomatic bone.
The dilator naris muscle is a part of the nasalis muscle. It is divided into posterior and anterior parts.
The Labyrinth or Lateral Mass of the ethmoid bone consists of a number of thin-walled cellular cavities, the ethmoidal cells, arranged in three groups, anterior, middle, and posterior, and interposed between two vertical plates of bone; the lateral plate forms part of the orbit, the medial plate forms part of the nasal cavity. In the disarticulated bone many of these cells are opened into, but when the bones are articulated, they are closed in at every part, except where they open into the nasal cavity.
The infraorbital canal is a canal found at the base of the orbit that opens on to the maxilla. It is continuous with the infraorbital groove and opens onto the maxilla at the infraorbital foramen. The infraorbital nerve and infraorbital artery travel through the canal.
The orbital process of the palatine bone is placed on a higher level than the sphenoidal, and is directed upward and lateralward from the front of the vertical part, to which it is connected by a constricted neck. It presents five surfaces, which enclose an air cell. Of these surfaces, three are articular and two non-articular.
The lateral or orbital surface of the lacrimal bone is divided by a vertical ridge, the posterior lacrimal crest, into two parts.
The anterior lacrimal crest is a bony projection on the frontal process of maxilla in the skull. It creates the lateral margin of the lacrimal sac fossa and is continuous with the orbital margin. At its junction with the orbital surface is a small tubercle, the lacrimal tubercle, which serves as a guide to the position of the lacrimal sac.The medial palpebral ligament is attached to anterior lacrimal crest.
Each Zygomatic process is the part of a bone which articulates with the zygomatic bone. The three processes are:
The frontal process of maxilla is a strong plate, which projects upward, medialward, and backward from the maxilla, forming part of the lateral boundary of the nose.
In human anatomy of the mouth, the palatine process of maxilla, is a thick, horizontal process of the maxilla. It forms the anterior three quarters of the hard palate, the horizontal plate of the palatine bone making up the rest.
Kileskus is a genus of tyrannosauroid dinosaur known from partial remains found in Middle Jurassic Itat Formation of Krasnoyarsk Krai, Russia. Fossils recovered include the holotype maxilla, a premaxilla, a surangular, and a few bones from the hand and foot. The skull bones are similar to those of Proceratosaurus. The type species is K. aristotocus. Kileskus was named in 2010 by Averianov and colleagues.
Zhuchengtyrannus is a genus of tyrannosaurid theropod dinosaur known from the Late Cretaceous period of Shandong Province, China. It belongs to the tyrannosaurinae subfamily, and contains a single species, Zhuchengtyrannus magnus.
Siamodon is an extinct genus of iguanodontian ornithopod dinosaur from Early Cretaceous deposits of northeastern Thailand.
Khunnuchelys was a genus of trionychine turtle from the Late Cretaceous of Asia. Three species are known, K. erinhotensis, the type species, K. kizylkumensis, and K. lophorhothon. K. erinhotensis lived in China from the late Turonian until the middle Campanian. K. kizylkumensis existed during the late Turonian of Uzbekistan. The third species, described in 2013 by Danilov et al., persisted from the early to middle Campanian of Kazakhstan.
Shuangbaisaurus is an extinct genus of theropod dinosaur, possibly a dilophosaurid, that lived in the Early Jurassic of Yunnan Province, China. It contains a single species, S. anlongbaoensis, represented by a partial skull. Like the theropods Dilophosaurus and Sinosaurus, the latter of which was its contemporary, Shuangbaisaurus bore a pair of thin, midline crests on its skull. Unusually, these crests extended backwards over the level of the eyes, which, along with the unusual orientation of the jugal bone, led the describers to name it as a new genus. However, Shuangbaisaurus also possesses a groove between its premaxilla and maxilla, a characteristic which has been used to characterize Sinosaurus as a genus. Among the two morphotypes present within the genus Sinosaurus, Shuangbaisaurus more closely resembles the morphotype that is variably treated as a distinct species, S. sinensis, in its relatively tall skull.
