The frontal process of maxilla is a strong plate, which projects upward, medialward, and backward from the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

, forming part of the lateral boundary of the

nose A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes th ...

. Its ''lateral surface'' is smooth, continuous with the anterior surface of the body, and gives attachment to the

quadratus labii superioris The levator labii superioris (pl. ''levatores labii superioris'', also called quadratus labii superioris, pl. ''quadrati labii superioris'') is a muscle of the human body used in facial expression. It is a broad sheet, the origin of which exten ...

, the

orbicularis oculi The orbicularis oculi is a muscle in the face that closes the eyelids. It arises from the nasal part of the frontal bone, from the frontal process of the maxilla in front of the lacrimal groove, and from the anterior surface and borders of a short ...

, and the

medial palpebral ligament The medial palpebral ligament (medial canthal tendon) is a ligament of the face. It attaches to the frontal process of the maxilla, the lacrimal groove, and the tarsus of each eyelid. It has a superficial (anterior) and a deep (posterior) layer ...

. Its ''medial surface'' forms part of the lateral wall of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal c ...

; at its upper part is a rough, uneven area, which articulates with the ethmoid, closing in the

anterior ethmoidal cells The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. The cells are variable in both size and number in the lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral e ...

; below this is an oblique ridge, the

ethmoidal crest The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. The cells are variable in both size and number in the lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral e ...

, the posterior end of which articulates with the

middle nasal concha The medial surface of the labyrinth of ethmoid consists of a thin lamella, which descends from the under surface of the cribriform plate, and ends below in a free, convoluted margin, the middle nasal concha (middle nasal turbinate). It is rough, a ...

, while the anterior part is termed the

agger nasi The agger nasi (from Latin: ''agger'' meaning "mound or heap") is a small ridge on the lateral side of the nasal cavity. It is located midway at the anterior edge of the middle nasal concha, directly above the atrium of the middle meatus. It is f ...

; the crest forms the upper limit of the atrium of the

middle meatus In anatomy, the term nasal meatus can refer to any of the three meatuses (passages) through the skulls nasal cavity: the superior meatus (''meatus nasi superior''), middle meatus (''meatus nasi medius''), and inferior meatus (''meatus nasi inferio ...

. The ''upper border'' articulates with the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.''Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, par ...

and the ''anterior'' with the nasal; the ''posterior border'' is thick, and hollowed into a groove, which is continuous below with the lacrimal groove on the nasal surface of the body: by the articulation of the medial margin of the groove with the anterior border of the lacrimal a corresponding groove on the lacrimal is brought into continuity, and together they form the lacrimal fossa for the lodgement of the

lacrimal sac The lacrimal sac or lachrymal sac is the upper dilated end of the nasolacrimal duct, and is lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla. It connects the lacrimal canaliculi, which drain tears from the ey ...

. The lateral margin of the groove is named the

anterior lacrimal crest The anterior lacrimal crest is a bony projection on the frontal process of the maxilla. It creates the lateral margin of the lacrimal sac fossa and is continuous with the orbital margin. The medial palpebral ligament is attached to anterior lac ...

, and is continuous below with the orbital margin; at its junction with the orbital surface is a small tubercle, the

lacrimal tubercle The lateral margin of the groove of the frontal process of the maxilla is named the anterior lacrimal crest, and is continuous below with the orbital margin; at its junction with the orbital surface is a small tubercle, the lacrimal tubercle, whi ...

, which serves as a guide to the position of the lacrimal sac.

Additional images

File:Frontal process of maxilla - animation01.gif, Frontal process shown in red. Animation. File:Frontal process of maxilla - animation02.gif, Left and right frontal process of maxilla, and upper teeth. Animation. File:Gray167.png, Articulation of left palatine bone with maxilla. File:Gray190.png, The skull from the front. File:Gray194.png, Sagittal section of skull. File:Gray196.png, Roof, floor, and lateral wall of left nasal cavity. File:Slide8hhhh.JPG, Frontal process of maxilla File:Slide11hhhh.JPG, Frontal process of maxilla

External links

* - "Osteology of the Skull: The Maxilla" * {{Authority control Bones of the head and neck