Categories: Skull | Head and neck | Foramina of the skull | Musculoskeletal system stubs This article is about the skeletal organs. ... Head and neck anatomy is a specialized study of the human body quite frequently studied in depth by surgeons, dentist, and dental technicians. ... This article or section does not adequately cite its references or sources. ... The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself. ... The squama of the occipital bone, situated above and behind the foramen magnum, is curved from above downward and from side to side. ... The inion is the most prominent projection of the occipital bone at the lower rear part of the skull. ... The nuchal lines are four curved lines on the external surface of the occipital bone: The upper, often faintly marked, is named the highest nuchal line, and to it the galea aponeurotica is attached. ... That part of the squama occipitalis which lies above the highest nuchal lines is named the planum occipitale (or occipital plane), and is covered by the Occipitalis muscle. ... That part of the squama occipitalis which lies below the highest nuchal lines is termed the planum nuchale (or nuchal plane), is rough and irregular for the attachment of several muscles. ... The internal surface of the occipital bone is deeply concave and divided into four fossæ by a cruciform eminence ( or cruciate eminence). ... In the occipital bone, at the point of intersection of the four divisions of the cruciate eminence is the internal occipital protuberance. ... The internal surface of the squama frontalis of the frontal bone is concave and presents in the upper part of the middle line a vertical groove, the sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest; the sulcus lodges the superior sagittal sinus, while... In the occipital bone, the lower division of the cruciate eminence is prominent, and is named the internal occipital crest; it bifurcates near the foramen magnum and gives attachment to the falx cerebelli; in the attached margin of this falx is the occipital sinus, which is sometimes duplicated. ... The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the condyles for articulation with the superior facets of the atlas. ... The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the occipital condyles for articulation with the superior facets of the atlas. ... The hypoglossal canal is a bony canal in the occipital bone of the skull that transmits the hypoglossal nerve from its point of entry near the medulla oblongata to its exit from the base of the skull near the jugular foramen. ... Behind either condyle of the lateral parts of occipital bone is a depression, the condyloid fossa (or condylar fossa), which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condyloid canal, through... In the lateral parts of occipital bone, behind either condyle is a depression, the condyloid fossa, which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condylar canal (or condyloid canal), through... In the lateral part of the occipital bone, extending lateralward from the posterior half of the condyle is a quadrilateral plate of bone, the jugular process, excavated in front by the jugular notch, which, in the articulated skull, forms the posterior part of the jugular foramen. ... The upper surface of the lateral parts of occipital bone presents an oval eminence, the jugular tubercle, which overlies the hypoglossal canal and is sometimes crossed by an oblique groove for the glossopharyngeal, vagus, and accessory nerves. ... The basilar part of the occipital bone extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. ... On the lower surface of the basilar part of occipital bone, about 1 cm. ... The parietal bones (os parietale) are bones in the human skull and form, by their union, the sides and roof of the cranium. ... The external surface of the parietal bone is convex, smooth, and marked near the center by an eminence, the parietal eminence (parietal tuber), which indicates the point where ossification commenced. ... Crossing the middle of the parietal bone in an arched direction are two curved lines, the superior and inferior temporal lines; the former gives attachment to the temporal fascia, and the latter indicates the upper limit of the muscular origin of the Temporalis. ... At the back part of the parietal bone and close to the upper or sagittal border is the parietal foramen, which transmits a vein to the superior sagittal sinus, and sometimes a small branch of the occipital artery; it is not constantly present, and its size varies considerably. ... The frontal bone (os frontale, TA: A02. ... There are two surfaces of the squama of the frontal bone: the external surface, and the internal surface. ... The frontal suture (sutura frontalis) is a dense connective tissue structure that divides the two halves of the frontal bone of the skull in infants and children. ... On the frontal bone, on either side of the frontal suture, about 3 cm. ... On the squama frontalis of the frontal bone, below the frontal eminences, and separated from them by a shallow groove, are two arched elevations, the superciliary arches; these are prominent medially, and are joined to one another by a smooth elevation named the glabella. ... The glabella is the space between the eyebrows and above the nose. ... Arching transversely below the superciliary arches is the upper part of the margin of the orbit, thin and prominent in its lateral two-thirds, rounded in its medial third, and presenting, at the junction of these two portions, the supraorbital notch or foramen for the supraorbital nerve and vessels. ... The supraorbital margin of the frontal bone ends laterally in the zygomatic process, which is strong and prominent, and articulates with the zygomatic bone. ... The internal surface of the squama frontalis of the frontal bone is concave and presents in the upper part of the middle line a vertical groove, the sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest; the sulcus lodges the superior sagittal sinus, while... The internal surface of the squama frontalis of the frontal bone is concave and presents in the upper part of the middle line a vertical groove, the sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest; the sulcus lodges the superior sagittal sinus, while... The frontal crest of the frontal bone ends below in a small notch which is converted into a foramen, the foramen cecum, by articulation with the ethmoid. ... The orbital or horizontal part of the frontal bone (pars orbitalis) consists of two thin triangular plates, the orbital plates, which form the vaults of the orbits, and are separated from one another by a median gap, the ethmoidal notch. ... The ethmoidal notch separates the two orbital plates; it is quadrilateral, and filled, in the articulated skull, by the cribriform plate of the ethmoid. ... The lacrimal bone (Os Lacrimale), the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit. ... Near the nasal part of the interior surface of the frontal bone is a depression, the trochlear fovea, or occasionally a small trochlear spine, for the attachment of the cartilaginous pulley of the Obliquus oculi superior. ... Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina (or canals). ... Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina (or canals). ... ... The frontal air sinuses are lined by mucous membrane, and each communicates with the corresponding nasal cavity by means of a passage called the frontonasal duct. ... The temporal bones (os temporales) are situated at the sides and base of the skull. ... The squama of the temporal bone forms the anterior and upper part of the bone, and is scale-like, thin, and translucent. ... The anterior root of the posterior end of the outer surface of the Squama temporalis, continuous with the lower border, is short but broad and strong; it is directed medialward and ends in a rounded eminence, the articular tubercle (eminentia articularis). ... In the temporal bone, between the posterior wall of the external acoustic meatus and the posterior root of the zygomatic process is the area called the suprameatal triangle, or mastoid fossa, through which an instrument may be pushed into the tympanic antrum. ... In the temporal bone, the mandibular fossa (glenoid fossa) is bounded, in front, by the articular tubercle; behind, by the tympanic part of the bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure (Glaserian fissure). ... The mandibular fossa is bounded, in front, by the articular tubercle; behind, by the tympanic part of the bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure (Glaserian fissure). ... The mastoid portion of the temporal bone (or mastoid process) forms the posterior part of the temporal bone. ... The outer surface of the temporal bone is perforated by numerous foramina; one of these, of large size, situated near the posterior border, is termed the mastoid foramen; it transmits a vein to the transverse sinus and a small branch of the occipital artery to the dura mater. ... The mastoid process (or mastoid bone) is a conical bump of the posterior portion of the temporal bone that is situated behind the ear in humans and many other vertebrates and serves as a site of neck muscle attachment (the Sternocleidomastoid, Splenius capitis, and Longissimus capitis). ... On the medial side of the mastoid process is a deep groove, the mastoid notch (digastric fossa), for the attachment of the Digastricus. ... On the medial side of the mastoid process of the temporal bone is a deep groove, the mastoid notch (digastric fossa), for the attachment of the Digastricus; medial to this is a shallow furrow, the occipital groove, which lodges the occipital artery. ... The inner surface of the mastoid portion of the temporal bone presents a deep, curved groove, the sigmoid sulcus, which lodges part of the transverse sinus; in it may be seen the opening of the mastoid foramen. ... Mastoid antrum (or tympanic antrum) is a cavity in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear via the aperture of the mastoid antrum. ... The petrous portion of the temporal bone or pyramid is pyramidal and is wedged in at the base of the skull between the sphenoid and occipital. ... The facial canal is a canal running from the internal acoustic meatus to the stylomastoid foramen. ... A shallow groove, sometimes double, leading lateralward and backward to an oblique opening, the hiatus of the facial canal, for the passage of the greater superficial petrosal nerve and the petrosal branch of the middle meningeal artery. ... Near the center of the posterior surface of the temporal bone is a large orifice, the internal acoustic meatus (or internal auditory meatus), the size of which varies considerably; its margins are smooth and rounded, and it leads into a short canal, about 1 cm. ... In the temporal bone, above and between the aquæductus vestibuli is an irregular depression which lodges a process of the dura mater and transmits a small vein; in the infant this depression is represented by a large fossa, the subarcuate fossa, which extends backward as a blind tunnel under... On the interior surface of the temporal bone, behind the rough surface of the apex, is the large circular aperture of the carotid canal, which ascends at first vertically, and then, making a bend, runs horizontally forward and medialward; it transmits into the cranium the internal carotid artery, and the... Medial to the opening for the carotid canal and close to its posterior border, in front of the jugular fossa, is a triangular depression; at the apex of this is a small opening, the aquaeductus cochleae (or cochlear aqueduct, or aqueduct of cochlea), which lodges a tubular prolongation of the... In the temporal bone, behind the openings for the carotid canal and the aquæductus cochleæ is a deep depression, the jugular fossa, of variable depth and size in different skulls; it lodges the bulb of the internal jugular vein. ... In the bony ridge dividing the carotid canal from the jugular fossa is the small inferior tympanic canaliculus for the passage of the tympanic branch of the glossopharyngeal nerve. ... In the lateral part of the jugular fossa of the temporal bone is the mastoid canaliculus for the entrance of the auricular branch of the vagus nerve. ... The styloid process is pointed piece of bone that extends down from the human skull, just below the ear. ... Between the styloid and mastoid processes is the stylomastoid foramen; it is the termination of the facial canal, and transmits the facial nerve and stylomastoid artery. ... The Petrosquamous suture is a cranial suture between the petrous portion and the squama of the temporal bone. ... The tympanic part of the temporal bone is a curved plate of bone lying below the squama and in front of the mastoid process. ... The inner end of the external acoustic meatus is closed, in the recent state, by the tympanic membrane; the upper limit of its outer orifice is formed by the posterior root of the zygomatic process, immediately below which there is sometimes seen a small spine, the suprameatal spine, situated at... The zygomatic process of the temporal bone is a long, arched process projecting from the lower part of the squamous portion of the temporal bone. ... The sphenoid bone (from Greek sphenoeides, wedgelike) is a bone situated at the base of the skull in front of the temporals and basilar part of the occipital. ... The body of the sphenoid bone, more or less cubical in shape, is hollowed out in its interior to form two large cavities, the sphenoidal air sinuses, which are separated from each other by a septum. ... The superior surface of the body of the sphenoid bone (Fig. ... The superior surface of the body of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove, prechiasmatic sulcus), above and behind which lies the optic chiasma. ... The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic... The Sella turcica (literally Turkish saddle) is a saddle-shaped depression in the sphenoid bone at the base of the human skull. ... In the sphenoid bone, behind the chiasmatic groove is an elevation, the tuberculum sellæ; and still more posteriorly, a deep depression, the sella turcica, the deepest part of which lodges the hypophysis cerebri and is known as the fossa hypophyseos (or fossa hypophysialis). ... The anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes. ... In the sphenoid bone, the anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes, while the posterior boundary is formed by a square-shaped plate of bone, the dorsum sellæ, ending at its superior angles in two tubercles... In the sphenoid bone, the anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes, while the posterior boundary is formed by a square-shaped plate of bone, the dorsum sellæ, ending at its superior angles in two tubercles... On either side of the dorsum sellae of the sphenoid bone is a notch for the passage of the abducent nerve, and below the notch a sharp process, the petrosal process, which articulates with the apex of the petrous portion of the temporal bone, and forms the medial boundary of... Behind the dorsum sellæ is a shallow depression, the clivus, which slopes obliquely backward, and is continuous with the groove on the basilar portion of the occipital bone; it supports the upper part of the pons. ... Above the attachment of each great wing of the sphenoid bone is a broad groove, curved something like the italic letter f; it lodges the internal carotid artery and the cavernous sinus, and is named the carotid groove. ... Along the posterior part of the lateral margin of the carotid groove of the sphenoid bone, in the angle between the body and great wing, is a ridge of bone, called the lingula. ... The sphenoidal sinuses (or sphenoid) contained within the body of the sphenoid vary in size and shape; owing to the lateral displacement of the intervening septum they are rarely symmetrical. ... The greater wing of the sphenoid bone, or ali-sphenoid, is a bony process of the sphenoid bone; there is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally, and backwards. ... The great wings, or ali-sphenoids, are two strong processes of bone, which arise from the sides of the body, and are curved upward, lateralward, and backward; the posterior part of each projects as a triangular process which fits into the angle between the squama and the petrous portion of... At th anterior and medial part of the Sphenoid is a circular aperture, the foramen rotundum, for the transmission of the maxillary nerve. ... At the base of the skull the foramen ovale is a hole that transmits the mandibular nerve, the otic ganglion, the accessory meningeal artery, emissary veins (from the cavernous sinus to the pterygoid plexus) and the lesser superficial petrosal nerve. ... In the base of the skull, in the great wings of the sphenoid bone, medial to the foramen ovale, a small aperture, the sphenoidal emissary foramen, may occasionally be seen (it is often absent) opposite the root of the pterygoid process. ... The foramen spinosum is the foramen in the skull that permits the passage of the middle meningeal artery. ... The lateral surface of the great wing is convex, and divided by a transverse ridge, the infratemporal crest, into two portions. ... The lateral half of the great wing articulates, by means of a synchondrosis, with the petrous portion of the temporal, and between the two bones on the under surface of the skull, is a furrow, the sulcus tubæ, for the lodgement of the cartilaginous part of the auditory tube. ... The lesser wings of the sphenoid or orbito-sphenoids are two thin triangular plates, which arise from the upper and anterior parts of the body, and, projecting lateralward, end in sharp points [Fig. ... 1 Foramen ethmoidale, 2 Canalis opticus, 3 Fissura orbitalis superior, 4 Fossa sacci lacrimalis, 5 Sulcus infraorbitalis, 6 Fissura orbitalis inferior, 7 Foramen infraorbitale The superior orbital fissure is a foramen in the skull, although strictly it is more of a cleft, lying between the lesser and greater wings of... In the sphenoid bone, the posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes joined to the middle clinoid process by a spicule of... The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic... The pterygoid processes of the sphenoid, one on either side, descend perpendicularly from the regions where the body and great wings unite. ... The Pterygoid fossa, or the sphenoid bone is wedged between several other bones in the front of the cranium. ... In the pterygoid processes of the sphenoid, above the pterygoid fossa is a small, oval, shallow depression, the scaphoid fossa, which gives origin to the Tensor veli palatini. ... The lateral pterygoid plate of the sphenoid (or lateral lamina of pterygoid process) is broad, thin, and everted; its lateral surface forms part of the medial wall of the infratemporal fossa, and gives attachment to the Pterygoideus externus; its medial surface forms part of the pterygoid fossa, and gives attachment... The medial pterygoid plate of the sphenoid is narrower and longer than the lateral pterygoid plate; it curves lateralward at its lower extremity into a hook-like process, the pterygoid hamulus, around which the tendon of the Tensor veli palatini glides. ... The pterygoid canal (also vidian canal) is a passage in the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa. ... The medial pterygoid plate of the sphenoid curves lateralward at its lower extremity into a hook-like process, the pterygoid hamulus, around which the tendon of the Tensor veli palatini glides. ... The sphenoidal conchae (sphenoidal turbinated processes) are two thin, curved plates, situated at the anterior and lower part of the body of the sphenoid. ... Your skull is in your back (this is obviously not true, I was just testing the website to see if it really works) The ethmoid bone (os ethmoidale) is a bone in the skull that separates the nasal cavity from the brain. ... The cribriform plate of the ethmoid bone (horizontal lamina) [Fig. ... The crista galli (Latin: crest of the cock) is a median ridge of bone that projects from the cribriform plate of the ethmoid bone. ... Bones and cartilages of septum of nose. ... 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, part of the... ethmoidal sinuses can be divided into 3: a) anterior b) middle c) posterior except the posterior ethmoidal sinus, all the ethmoidal sinuses will drain into middle meateus. ... The lateral surface of the labyrinth of the ethmoid bone is formed of a thin, smooth, oblong plate, the lamina papyracea, which covers in the middle and posterior ethmoidal cells and forms a large part of the medial wall of the orbit; it articulates above with the orbital plate of... In the ethmoid bone, a curved lamina, the uncinate process, projects downward and backward from this part of the labyrinth; it forms a small part of the medial wall of the maxillary sinus, and articulates with the ethmoidal process of the inferior 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. ... The superior meatus, the smallest of the three meatuses of the nose, occupies the middle third of the lateral wall. ... The back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha. ... The middle meatus is situated between the middle and inferior conchæ, and extends from the anterior to the posterior end of the latter. ... The following is a list of holes, or foramina, in the base of the skull and what goes through each of them. ... The frontal crest of the frontal bone ends below in a small notch which is converted into a foramen, the foramen cecum, by articulation with the ethmoid. ... Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina (or canals). ... Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina (or canals). ... When the two maxillæ are articulated, a funnel-shaped opening, the incisive foramen, is seen in the middle line, immediately behind the incisor teeth. ... Behind the carotid canal is the jugular foramen, a large aperture, formed in front by the petrous portion of the temporal, and behind by the occipital; it is generally larger on the right than on the left side, and may be subdivided into three compartments. ... The foramen lacerum (Latin for lacerated piercing) is a triangular hole in the base of the skull located at the base of the medial pterygoid plate. ... The Mandibular Foramen is an opening on the internal surface of the ramus for the mandibular vessels and nerve to pass. ... The outer surface of the temporal bone is perforated by numerous foramina; one of these, of large size, situated near the posterior border, is termed the mastoid foramen; it transmits a vein to the transverse sinus and a small branch of the occipital artery to the dura mater. ... The mental foramen is a foramen in the mandible. ... The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic... Above the canine fossa is the infraorbital foramen, the end of the infraorbital canal; it transmits the infraorbital vessels and nerve. ... Arching transversely below the superciliary arches is the upper part of the margin of the orbit, thin and prominent in its lateral two-thirds, rounded in its medial third, and presenting, at the junction of these two portions, the supraorbital notch or foramen for the supraorbital nerve and vessels. ... At the base of the skull the foramen ovale is a hole that transmits the mandibular nerve, the otic ganglion, the accessory meningeal artery, emissary veins (from the cavernous sinus to the pterygoid plexus) and the lesser superficial petrosal nerve. ... At either posterior angle of the hard palate is the greater palatine foramen, for the transmission of the descending palatine vessels and anterior palatine nerve; and running forward and medialward from it a groove, for the same vessels and nerve. ... Behind the posterior palatine foramen is the pyramidal process of the palatine bone, perforated by one or more lesser palatine foramina, and marked by the commencement of a transverse ridge, for the attachment of the tendinous expansion of the Tensor veli palatini. ... At the back part of the parietal bone and close to the upper or sagittal border is the parietal foramen, which transmits a vein to the superior sagittal sinus, and sometimes a small branch of the occipital artery; it is not constantly present, and its size varies considerably. ... At th anterior and medial part of the Sphenoid is a circular aperture, the foramen rotundum, for the transmission of the maxillary nerve. ... The processes of the superior border of the palatine bone are separated by the sphenopalatine notch, which is converted into the sphenopalatine foramen by the under surface of the body of the sphenoid. ... The foramen spinosum is the foramen in the skull that permits the passage of the middle meningeal artery. ... Between the styloid and mastoid processes is the stylomastoid foramen; it is the termination of the facial canal, and transmits the facial nerve and stylomastoid artery. ... The malar surface of the zygomatic bone is convex and perforated near its center by a small aperture, the zygomaticofacial foramen, for the passage of the zygomaticofacial nerve and vessels; below this foramen is a slight elevation, which gives origin to the Zygomaticus. ... Near the center of the temporal surface of the zygomatic bone is the zygomaticotemporal foramen for the transmission of the zygomaticotemporal nerve. ... On the interior surface of the temporal bone, behind the rough surface of the apex, is the large circular aperture of the carotid canal, which ascends at first vertically, and then, making a bend, runs horizontally forward and medialward; it transmits into the cranium the internal carotid artery, and the... In the lateral parts of occipital bone, behind either condyle is a depression, the condyloid fossa, which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condylar canal (or condyloid canal), through... The hypoglossal canal is a bony canal in the occipital bone of the skull that transmits the hypoglossal nerve from its point of entry near the medulla oblongata to its exit from the base of the skull near the jugular foramen. ... In the opening of the incisive foramen, the orifices of two lateral canals are visible; they are named the incisive canals or foramina of Stenson; through each of them passes the terminal branch of the descending palatine artery and the nasopalatine nerve. ... The pterygoid canal (also vidian canal) is a passage in the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa. ... The lateral wall and the floor of the orbit are separated posteriorly by the inferior orbital fissure which transmits the maxillary nerve and its zygomatic branch, the infraorbital vessels, and the ascending branches from the sphenopalatine ganglion. ... 1 Foramen ethmoidale, 2 Canalis opticus, 3 Fissura orbitalis superior, 4 Fossa sacci lacrimalis, 5 Sulcus infraorbitalis, 6 Fissura orbitalis inferior, 7 Foramen infraorbitale The superior orbital fissure is a foramen in the skull, although strictly it is more of a cleft, lying between the lesser and greater wings of... The mandibular fossa is bounded, in front, by the articular tubercle; behind, by the tympanic part of the bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure (Glaserian fissure). ... The ear canal (external auditory meatus, external acoustic meatus), is a tube running from the outer ear to the middle ear. ... Near the center of the posterior surface of the temporal bone is a large orifice, the internal acoustic meatus (or internal auditory meatus), the size of which varies considerably; its margins are smooth and rounded, and it leads into a short canal, about 1 cm. ... The cribriform plate of the ethmoid bone (horizontal lamina) [Fig. ... Image File history File links Download high-resolution version (609x1165, 138 KB) Plastische Anatomie des menschlichen Körpers für Künstler und freunde der kunst von Dr. Julius Kollmann o. ... The musculoskeletal system (also known as the locomotor system) is an organ system that gives animals the ability to physically move using the muscles and skeletal system. ...