In human anatomy, the pterygopalatine fossa is a fossa in the skull. A human skull contains two pterygopalatine fossae—one on the left side, another on the right side; each fossa is a cone-shaped paired depression deep to the infratemporal fossa and posterior to the maxilla on each side of the skull, located between the pterygoid process and the maxillary tuberosity close to the apex of the orbit. It is the indented area medial to the pterygomaxillary fissure leading into the sphenopalatine foramen, it communicates with the nasal and oral cavities, infratemporal fossa, orbit and middle cranial fossa through eight foramina. It has the following boundaries: anterior: superomedial part of the infratemporal surface of maxilla posterior: root of the pterygoid process and adjoining anterior surface of the greater wing of sphenoid bone medial: perpendicular plate of the palatine bone and its orbital and sphenoidal processes lateral: pterygomaxillary fissure inferior: part of the floor is formed by the pyramidal process of the palatine bone.
The following passages connect the fossa with other parts of the skull: The pterygopalatine fossa contains the pterygopalatine ganglion suspended by nerve roots from the maxillary nerve the terminal third of the maxillary artery the maxillary nerve, with, the nerve of the pterygoid canal, a combination of the greater petrosal nerve and the deep petrosal nerve. To obtain block anesthesia of the entire second division of the trigeminal nerve, an intraoral injection can be administered into this area. Pterygopalatine canal Fossa in the Human Body Interactive at Columbia.edu
Angle of the mandible
The angle of the mandible is located at the posterior border at the junction of the lower border of the ramus of the mandible. The angle of the mandible, which may be either inverted or everted, is marked by rough, oblique ridges on each side, for the attachment of the masseter laterally, the pterygoideus internus medially; the forensic term for the midpoint of the mandibular angle is the gonion. The gonion is a cephalometric landmark located at the lowest and lateral point on the angle; this site is at the apex of the maximum curvature of the mandible, where the ascending ramus becomes the body of the mandible. The mandibular angle has been named as a forensic tool for gender determination, but recent studies have called into question whether there is any significant sex difference in humans in the angle. Ohngren's line This article incorporates text in the public domain from page 174 of the 20th edition of Gray's Anatomy lesson4 at The Anatomy Lesson by Wesley Norman Anatomy photo:34:st-0202 at the SUNY Downstate Medical Center - "Oral Cavity: Bones" "Anatomy diagram: 34256.000-2".
Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014-01-01. Anatomy image: skel/mandible2 at Human Anatomy Lecture, Pennsylvania State University
The point of junction of the maxillary bone, lacrimal bone, frontal bone is named the dacryon. This article incorporates text in the public domain from page 189 of the 20th edition of Gray's Anatomy
The anterior fontanelle is the largest fontanelle, is placed at the junction of the sagittal suture, coronal suture, frontal suture. The fontanelle allows the skull to deform during birth to ease its passage through the birth canal and for expansion of the brain after birth; the anterior fontanelle closes between the ages of 12 and 18 months. The anterior fontanelle is useful clinically. Examination of an infant includes palpating the anterior fontanelle. A sunken fontanelle indicates dehydration whereas a tense or bulging anterior fontanelle indicates raised intracranial pressure. However, this is not a certain indicator for raised pressure as prolonged crying by the baby may produce the same effect. A full anterior fontanelle may be indicative of neonatal meningitis acute bacterial meningitis. Bregma Anatomy image: skel/fetal2 at Human Anatomy Lecture, Pennsylvania State University
The infratemporal fossa is an irregularly shaped cavity, situated below and medial to the zygomatic arch. It is not enclosed by bone in all directions, it contains superficial muscles that are visible during dissection after removing skin and fascia: namely, the lower part of the temporalis muscle, the lateral pterygoid, the medial pterygoid, its boundaries may be defined by: anteriorly, by the infratemporal surface of the maxilla and the ridge which descends from its zygomatic process posteriorly, by the articular tubercle of the temporal and the spina angularis of the sphenoid superiorly, by the greater wing of the sphenoid below the infratemporal crest, by the under surface of the temporal squama, containing the foramen ovale, which transmits the mandibular branch of the trigeminal nerve, the foramen spinosum, which transmits the middle meningeal artery inferiorly, by the medial pterygoid muscle attaching to the mandible medially, by the lateral pterygoid plate laterally, by the ramus of mandible, which contains the mandibular foramen, leading to the mandibular canal through which the inferior alveolar nerve passes.
This contains the lingula, a triangular piece of bone that overlies the mandibular foramen antero-medially. The mylohyoid groove descends obliquely transmitting the mylohyoid nerve the only motor branch of the posterior division of the trigeminal nerve. Lower part of the Temporalis and masseter muscles Lateral and medial pterygoid muscles The internal maxillary vessels, consisting of the maxillary artery originating from the external carotid artery and its branches. Internal maxillary branches found within the infratemporal fossa including the middle meningeal artery inferior alveolar artery deep temporal artery buccal artery pterygoid venous plexus retromandibular vein Mandibular nerve, inferior alveolar nerve, lingual nerve, buccal nerve, chorda tympani nerve, otic ganglion. Mandibular nerve, the third branch of the trigeminal nerve known as the "inferior maxillary nerve" or nervus mandibularis, enters infratemporal fossa from middle cranial fossa through foramen ovale. Motor branches: masseteric nerve deep temporal nerve lateral pterygoid nerve and medial pterygoid nerveIts motor fibers innervate all the muscles of mastication plus the mylohyoid, anterior belly of the digastric, the tensores veli palati and tympani Sensory innervation: meningeal nerve buccal nerve auriculotemporal nerve lingual nerve inferior alveolar nerve auricle external acoustic meatus tympanic membrane temporal region cheek skin overlying the mandible floor of mouth lower teeth gingiva Middle cranial fossa.
Temporal fossa. Pterygopalatine fossa. Orbit. Parapharyngeal space; the foramen ovale and foramen spinosum open on its roof, the alveolar canals on its anterior wall. At its upper and medial part are two fissures, which together form a T-shaped fissure, the horizontal limb being named the inferior orbital, the vertical one the pterygomaxillary; this article incorporates text in the public domain from page 184 of the 20th edition of Gray's Anatomy
Base of skull
The base of skull known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the lower parts of the skull roof. Structures found at the base of the skull are for example: There are five bones that make up the base of the skull: Ethmoid bone Sphenoid bone Occipital bone Frontal bone Temporal bone Occipital sinus Superior sagittal sinus Superior petrosal sinus Foramen cecum Optic foramen Foramen lacerum Foramen rotundum Foramen magnum Foramen ovale Jugular foramen Internal auditory meatus Mastoid foramen Sphenoidal emissary foramen Foramen spinosum Frontoethmoidal suture Sphenofrontal suture Sphenopetrosal suture Sphenoethmoidal suture Petrosquamous suture Sphenosquamosal suture Sphenoidal lingula Subarcuate fossa Dorsum sellae Jugular process Petro-occipital fissure Condylar canal Jugular tubercle Tuberculum sellae Carotid groove Fossa hypophyseos Posterior clinoid processes Sigmoid sulcus Internal occipital protuberance Internal occipital crest Ethmoidal spine Vestibular aqueduct Chiasmatic groove Middle clinoid process Groove for sigmoid sinus Trigeminal ganglion Middle cranial fossa Anterior cranial fossa Middle meningeal artery Cribriform plate Posterior cranial fossa Nasociliary nerve Hypoglossal canal
The asterion is the point on the skull corresponding to the posterior end of the parietomastoid suture. In human anatomy, the asterion is a visible, so-called craniometric, point on the exposed skull, just behind the ear, where three cranial sutures meet: the lambdoid, parieto-mastoid, occipito-mastoid sutures,or where three cranial bones meet: Parietal bone, Occipital bone, Mastoid portion of the Temporal bone. In the adult, it lies 4 cm behind and 12 mm above the center of the entrance to the ear canal. Neurosurgeons use this point to orient themselves, in order to plan safe entry into the skull for some operations, such as retro-sigmoid approach; the asterion receives its name from the Greek ἀστέριον, meaning "star" or "starry". The Mercedes point is an alternative term for the asterion, for its resemblance to the Mercedes-Benz logo