This article is about the maxilla in vertebrates. For arthropod maxillae, see Maxilla (arthropod mouthpart).
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Maxilla
Side view. Maxilla visible at bottom left, in green.
Front view. Maxilla visible at center, in green.
Details
Precursor
1st branchial arch[1]
Identifiers
MeSH
D008437
TA
A02.1.12.001
FMA
9711
Anatomical terms of bone
[edit on Wikidata]
The maxilla (plural: maxillae/mækˈsɪliː/)[2] 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.[3][4] The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.
Contents
1Structure
1.1Articulations
1.2Development
1.2.1Changes by age
2Function
3Clinical significance
4In other animals
5Additional images
6See also
7References
8Further reading
9External links
Structure
Inferior surface of maxilla
In humans, the maxilla consists of:
The body of the maxilla
Four processes
The zygomatic process
The frontal process of maxilla
The alveolar process
The palatine process
Three surfaces - anterior, posterior, medial
The Infraorbital foramen
The maxillary sinus
The incisive foramen
Articulations
Each maxilla articulates with nine bones:
two of the cranium: the frontal and ethmoid
seven of the face: the nasal, zygomatic, lacrimal, inferior nasal concha, palatine, vomer, and the adjacent fused maxilla.
Sometimes it articulates with the orbital surface, and sometimes with the lateral pterygoid plate of the sphenoid.
Development
Figure 5: Anterior surface of maxilla at birth.
Figure 6: Inferior surface of maxilla at birth.
The maxilla is ossified in membrane. Mall and Fawcett maintain that it is ossified from two centers only, one for the maxilla proper and one for the premaxilla.[5][6]
These centers appear during the sixth week of prenatal development and unite in the beginning of the third month, but the suture between the two portions persists on the palate until nearly middle life. Mall states that the frontal process is developed from both centers.
The maxillary sinus appears as a shallow groove on the nasal surface of the bone about the fourth month of development, but does not reach its full size until after the second dentition.
The maxilla was formerly described as ossifying from six centers, viz.,
one, the orbitonasal, forms that portion of the body of the bone which lies medial to the infraorbital canal, including the medial part of the floor of the orbit and the lateral wall of the nasal cavity;
a second, the zygomatic, gives origin to the portion which lies lateral to the infraorbital canal, including the zygomatic process;
from a third, the palatine, is developed the palatine process posterior to the incisive canal together with the adjoining part of the nasal wall;
a fourth, the premaxillary, forms the incisive bone which carries the incisor teeth and corresponds to the premaxilla of the lower vertebrates;
a fifth, the nasal, gives rise to the frontal process and the portion above the canine tooth;
and a sixth, the infravomerine, lies between the palatine and premaxillary centers and beneath the vomer; this center, together with the corresponding center of the opposite bone, separates the incisive canals from each other.
Changes by age
At birth the transverse and antero-posterior diameters of the bone are each greater than the vertical.
The frontal process is well-marked and the body of the bone consists of little more than the alveolar process, the teeth sockets reaching almost to the floor of the orbit.
The maxillary sinus presents the appearance of a furrow on the lateral wall of the nose. In the adult the vertical diameter is the greatest, owing to the development of the alveolar process and the increase in size of the sinus.
Function
Fracture of the left lacrimal / maxillary bone
The alveolar process of the maxillae holds the upper teeth, and is referred to as the maxillary arch. Each maxilla attaches laterally to the zygomatic bones (cheek bones).
Each maxilla assists in forming the boundaries of three cavities:
the roof of the mouth
the floor and lateral wall of the nasal cavity
the wall of the orbit
Each maxilla also enters into the formation of two fossae: the infratemporal and pterygopalatine, and two fissures, the inferior orbital and pterygomaxillary.
-When the tender bones of the upper jaw and lower nostril are severely or repetitively damaged, at any age the surrounding cartilage can begin to deteriorate just as it does after death.[citation needed]
Clinical significance
Maxilla fractures is a form of facial fracture caused by a fracture. A maxilla fracture is often the result of facial trauma such as violence, falls or automobile accidents. Maxilla fractures are classified according to the Le Fort classification.
In other animals
Sometimes (e.g. in bony fish), the maxilla is called "upper maxilla", with the mandible being the "lower maxilla". Conversely, in birds the upper jaw is often called "upper mandible".
In most vertebrates, the foremost part of the upper jaw, to which the incisors are attached in mammals consists of a separate pair of bones, the premaxillae. These fuse with the maxilla proper to form the bone found in humans, and some other mammals. In bony fish, amphibians, and reptiles, both maxilla and premaxilla are relatively plate-like bones, forming only the sides of the upper jaw, and part of the face, with the premaxilla also forming the lower boundary of the nostrils. However, in mammals, the bones have curved inward, creating the palatine process and thereby also forming part of the roof of the mouth.[7]
Birds do not have a maxilla in the strict sense; the corresponding part of their beaks (mainly consisting of the premaxilla) is called "upper mandible".
Cartilaginous fish, such as sharks, also lack a true maxilla. Their upper jaw is instead formed from a cartilaginous bar that is not homologous with the bone found in other vertebrates.[7]
Additional images
Skull. Maxilla shown in green.
See also
Wikimedia Commons has media related to Maxilla.
This article uses anatomical terminology; for an overview, see anatomical terminology.
Maxillofacial surgery
Maxillary crest
References
This article incorporates text in the public domain from page 157 of the 20th edition of Gray's Anatomy (1918)
^hednk-023—Embryo Images at University of North Carolina
^OED 2nd edition, 1989.
^Merriam-Webster Online Dictionary.
^Fehrenbach; Herring (2012). Illustrated Anatomy of the Head and Neck. Elsevier. p. 55. ISBN 978-1-4377-2419-6.
^Mall, Franklin P. (1906). "On ossification centers in human embryos less than one hundred days old". American Journal of Anatomy. 5 (4): 433–458. doi:10.1002/aja.1000050403.
^Fawcett, Edward (1911). "Some Notes on the Epiphyses of the Ribs". Journal of Anatomy and Physiology. 45 (Pt 2): 172–178. PMC 1288875. PMID 17232872.
^ abRomer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. pp. 217–43. ISBN 0-03-910284-X.
Further reading
Sicher, Harry; Du Brul, E. Lloyd (1975). Oral Anatomy (6th ed.). St. Louis: Mosby. ISBN 0-8016-4604-9.
Worthington, Philip; Evans, John R., eds. (1994). Controversies in Oral & Maxillofacial Surgery. Saunders. ISBN 0-7216-3099-5.
External links
Anatomy photo:22:os-1901 at the SUNY Downstate Medical Center
v
t
e
The orbit of the eye
Bones
Frontal bone
Zygomatic bone
Maxillary bone
Sphenoid bone
Ethmoid bone
Palatine bone
Lacrimal bone
Muscles
Superior rectus muscle
Inferior rectus muscle
Lateral rectus muscle
Medial rectus muscle
Superior oblique muscle
Trochlea of superior oblique
Inferior oblique muscle
Eyelid
Levator palpebrae superioris muscle
Tarsus
Medial palpebral ligament
Epicanthic fold
Meibomian gland
Ciliary glands
Eyelash
Palpebral fissure
Canthus
Gland of Zeis
Lacrimal apparatus
Krause's glands
Lacrimal canaliculi
Lacrimal caruncle
Lacrimal gland
Lacrimal lake
Lacrimal papilla
Lacrimal punctum
Lacrimal sac
Nasolacrimal duct
Other
Eyebrow
Unibrow
Conjunctiva
Plica semilunaris
Orbital septum
Periorbita
Suspensory ligament of eyeball
Tenon's capsule
v
t
e
The facial skeleton of the skull
Maxilla
Surfaces
Anterior: fossae (Incisive fossa, Canine fossa)
Infraorbital foramen
Orbital bones
Anterior nasal spine
Infratemporal: Alveolar canals
Maxillary tuberosity
Orbital: Infraorbital groove
Infraorbital canal
Nasal: Greater palatine canal
Processes
Zygomatic process
Frontal process (Agger nasi, Anterior lacrimal crest)
Alveolar process
Palatine process (Incisive foramen, Incisive canals, Foramina of Scarpa, Incisive bone, Anterior nasal spine)
… opening and closing of the mouth, with attention to any jaw or dental protrusion. Check to see if the upper teeth and lower teeth are aligned. Look for jaw deviation on opening and closing. Abnormal mandibular …
…positioned toward the tongue (lingually positioned) Class II relationship (the upper jaw protrudes too far in front of the lower jaw) A meta-analysis verified these findings for the primary dentition but noted …
… projects the entire lower facial skeleton and attached soft tissues forward. The upper and lower teeth are moved with the jaw bones either in native occlusion or moved differentially to correct an anterior-posterior …
… Clefting anomalies of the upper lip are more common and more varied than clefting anomalies of the lower lip because fusion of the components of the upper lip occurs later in… a structure, the more opportunities for malformation. Defects in the formation and growth of the jaw, oral cavity, and pharynx lead to a variety of malformations. The embryology, clinical features, and …
… masses or growths that reduce upper airway size, leading to OSA. The methods of upper airway imaging and the clinical settings in which upper airway imaging may be helpful… a surgical procedure that moves the top of the jaw (maxilla) and the bottom of the jaw (mandible) forward.…
English Journal
Comparative evaluation of the stability of two different dental implant designs and surgical protocols-a pilot study.
… Alepes kleinii is distinguishable from its congeners by the following combination of characters: two rows of small conical teeth arranged irregularly in a narrow band on upperjaw but those on lower jaw in a single series, a diffuse dusky blotch present on upper margin of opercle, and straight part of lateral line starting behind below origin of second dorsal fin. …
