Human Anatomy - Kotsan I. Ya. 2009

Skull
Variants and developmental anomalies of the cranial bones

Variants and Developmental anomalies of the Skull bones are quite common. Let us examine the most typical ones.

Occipital bone. Additional skull bones (sutural bones, ossa suturalia) are frequently present around the occipital bone. Occasionally, the external occipital protuberance reaches a considerable size. A third occipital condyle is also found, located near the anterior margin of the foramen magnum. It articulates with the anterior arch of the atlas via an accessory joint. Rarely, complete or partial fusion of the occipital condyles with the first cervical vertebra occurs.

Frontal bone. Often, the frontal bone consists of two parts separated by a persistent frontal suture. Sometimes, the pneumatic frontal sinuses are absent.

Sphenoid bone. The oval and spinous foramina occasionally merge into a single common opening, whereas the spinous foramen may be completely absent.

Ethmoid bone. An additional concha—the supreme nasal concha (concha nasalis suprema)—is not uncommon.

Parietal bone. Due to the non-fusion of ossification centers, each parietal bone may consist of upper and lower halves.

Temporal bone. The styloid process of the temporal bone may be absent or exceptionally long (sometimes reaching the Hyoid bone).

Maxilla. The incisive canal and maxillary sinus vary greatly in size and shape. Occasionally, clefting of the soft Tissues of the maxilla occurs—a cleft lip (labium leporinum). The most severe developmental defect of the maxilla is a cleft hard palate—a cleft palate (faux lupinum), or more precisely, the failure of fusion between the palatine processes of the maxillae and the horizontal plates of the palatine bones.

Mandible. Doubling of the mental foramen and the mandibular canal can be observed. The right and left halves of the mandibular body are frequently asymmetric.

Vomer. It may be deviated to the right or left.

Zygomatic bone. Sometimes a horizontal suture is present, dividing the zygomatic bone into two halves.

Nasal bone. Nasal bones are frequently asymmetric or fused, forming a single combined nasal bone.

Lacrimal bone. Its size and shape are variable; sometimes the absence of this bone is compensated for by an enlarged frontal process of the maxilla or the orbital plate of the ethmoid bone.

Inferior nasal concha. The bone may vary in shape and size.

Hyoid bone. The dimensions of the body of the hyoid bone, as well as its greater and lesser horns, are variable.

Key Latin terms

Cerebral cranium — cranium cerebrale, neurocranium

Occipital bone — os occipitale

Foramen magnum — foramen magnum

Basilar part — pars basilaris

Clivus — clivus

Pharyngeal tubercle — tuberculum pharyngeum

Sulcus for inferior petrosal sinus — sulcus sinus petrosi inferioris

Lateral part — pars lateralis

Occipital condyle — condylus occipitalis

Hypoglossal canal — canalis hypoglossi

Condylar fossa — fossa condylaris

Condylar canal — canalis condylaris

Jugular notch — incisura jugularis

Jugular process — processus jugularis

Groove for sigmoid sinus — sulcus sinus sigmoidei

Occipital squama — squama occipitalis

External occipital protuberance — protuberantia occipitalis externa

External occipital crest — crista occipitalis externa

Superior nuchal line — linea nuchalis superior

Inferior nuchal line — linea nuchalis inferior

Highest nuchal line — linea nuchalis suprema

Internal occipital protuberance — protuberantia occipitalis interna

Internal occipital crest — crista occipitalis interna

Cruciform eminence — eminentia cruciformis

Groove for transverse sinus — sulcus sinus transversi

Groove for superior sagittal sinus — sulcus sinus sagittalis superioris

Cerebral fossa — fossa cerebralis

Cerebellar fossa — fossa cerebellaris

Frontal bone — os frontale

Frontal squama — squama frontalis

External surface — facies externa

Internal surface — facies interna

Temporal surface — facies temporalis

Supraorbital margin — margo supraorbitalis

Supraorbital notch — incisura supraorbitalis

Supraorbital foramen — foramen supraorbitale

Frontal notch — incisura frontalis

Frontal foramen — foramen frontale

Zygomatic process — processus zygomaticus

Temporal line — linea temporalis

Superciliary arch — arcus superciliaris

Glabella — glabella

Frontal tuber — tuber frontale

Frontal suture — sutura frontalis

Groove for superior sagittal sinus — sulcus sinus sagittalis superioris

Frontal crest — crista frontalis

Foramen caecum — foramen caecum

Orbital part — pars orbitalis

Ethmoidal notch — incisura ethmoidalis

Digital impressions — impressiones digitatae

Cerebral juga (ridges) — juga cerebralia

Fossa for lacrimal gland — fossa glandulae lacrimalis

Trochlear fossa — fovea trochlearis

Trochlear spine — spina trochlearis

Nasal part — pars nasalis

Nasal spine — spina nasalis

Frontal sinus — sinus frontalis

Opening (aperture) of frontal sinus — apertura sinus frontalis

Frontal sinus septum — septum intersinuale frontale

Sphenoid bone — os sphenoidale

Body — corpus

Sphenoidal sinus — sinus sphenoidalis

Intersphenoidal septum — septum intersinuale sphenoidale

Aperture of sphenoidal sinus — apertura sinus sphenoidalis

Sella turcica — sella turcica

Hypophysial fossa — fossa hypophysialis

Tuberculum sellae — tuberculum sellae

Dorsum sellae — dorsum sellae

Posterior clinoid process — processus clinoideus posterior

Carotid sulcus — sulcus caroticus

Sphenoidal lingula — lingula sphenoidalis

Sphenoidal crest — crista sphenoidale

Sphenoidal rostrum — rostrum sphenoidalis

Sphenoidal concha — concha sphenoidalis

Lesser wing — ala minor

Anterior clinoid process — processus clinoideus anterior

Optic canal — canalis opticus

Superior orbital fissure — fissura orbitalis superior

Greater wing — ala major

Cerebral surface — facies cerebralis

Orbital surface — facies orbitalis

Temporal surface — facies temporalis

Infratemporal crest — crista infratemporalis

Maxillary surface — facies maxillaris

Round foramen — foramen rotundum

Oval foramen — foramen ovale

Spinosum foramen — foramen spinosum

Pterygoid process — processus pterygoideus

Pterygoid canal — canalis pterygoideus

Lateral plate — lamina lateralis

Medial plate — lamina medialis

Pterygoid fossa — fossa pterygoidea

Pterygoid notch — incisura pterygoidea

Pterygoid hamulus — hamulus pterygoideus

Sulcus of the pterygoid hamulus — sulcus hamuli pterygoidei

Scaphoid fossa — fossa scaphoidea

Sulcus of the auditory tube — sulcus tubae auditoriae

Vaginal process — processus vaginalis

Ethmoid bone — os ethmoidale

Cribriform plate — lamina cribrosa

Perpendicular plate — lamina perpendicularis

Crista galli — crista galli

Wing of the crista galli — ala cristae galli

Ethmoidal labyrinth — labyrinthus ethmoidalis

Ethmoidal Cells — cellulae ethmoidales

Orbital plate — lamina orbitalis

Superior nasal concha — concha nasalis superior

Middle nasal concha — concha nasalis media

Supreme nasal concha — concha nasalis suprema

Uncinate process — processus uncinatus

Ethmoidal bulla — bulla ethmoidalis

Semilunar hiatus — hiatus semilunaris

Ethmoidal infundibulum — infundibulum ethmoidale

Temporal bone — os temporale

Squamous part — pars squamosa

Cerebral surface — facies cerebralis

Temporal surface — facies temporalis

Groove for middle temporal artery — sulcus arteriae temporalis mediae

Sphenoidal margin — margo sphenoidalis

Parietal margin — margo parietalis

Parietal notch — incisura parietalis

Zygomatic process — processus zygomaticus

Zygomatic arch — arcus zygomaticus

Mandibular fossa — fossa mandibularis

Articular tubercle — tuberculum articulare

Tympanic part — pars tympanica

External acoustic meatus — meatus acusticus externus

External acoustic pore — porus acusticus externus

Tympanosquamous fissure — fissura tympanosquamosa

Petrosquamous fissure — fissura petrosquamosa

Petrotympanic fissure — fissura petrotympanica

Tympanomastoid fissure — fissura tympanomastoidea

Sheath of styloid process — Vagina processus styloidei

Petrous part — pars petrosa

Anterior border of the petrous part — margo anterior partis petrosae

Musculotubal canal — canalis musculotubarius

Semicanal for the tensor tympani Muscle — semicanalis musculi tensoris tympani

Semicanal of the pharyngotympanic tube — semicanalis tubae auditoriae

Posterior border of the petrous part — margo posterior partis petrosae

Sulcus for the inferior petrosal sinus — sulcus sinuspetrosi inferior

Superior border of the petrous part — margo superior partis petrosae

Sulcus for the superior petrosal sinus — sulcus sinus petrosi superior

Anterior surface of the petrous part — facies anterior partis petrosae

Arcuate eminence — eminentia arcuata

Tegmen tympani — tegmen tympani

Hiatus for the canal for greater petrosal nerve — hiatus canalis nervus petrosi majoris

Trigeminal impression — impressio trigeminalis

Sulcus for the greater petrosal nerve — sulcus nervuspetrosi majoris

Hiatus for the canal for lesser petrosal nerve — hiatus canalis nervus petrosi minoris

Sulcus for the lesser petrosal nerve — sulcus nervus petrosi minoris

Posterior surface of the petrous part — facies posterior partis petrosae

Internal acoustic opening — porus acusticus internus

Internal acoustic meatus — meatus acusticus internus

Subarcuate fossa — fossa subarcuata

External aperture of the vestibular aqueduct — apertura externa aqueductus vestibuli

Inferior surface of the petrous part — facies inferior partis petrosae

Jugular fossa — fossa jugularis

Mastoid canaliculus — canaliculus mastoideus

Jugular notch — incisura jugularis

Jugular foramen — foramen jugulare

Carotid canal — canalis caroticus

Caroticotympanic canaliculi — canaliculi caroticotympanici

Petrosal fossa — fossula petrosa

Inferior aperture of tympanic canaliculus — apertura inferior canaliculi tympanici

Styloid process — processus styloideus

Stylomastoid foramen — foramen stylomastoideum

Mastoid process — processus mastoideus

Groove for occipital artery —sulcus arteria occipitalis

Groove for sigmoid sinus — sulcus sinus sigmoidei

Mastoid cells — cellulae mastoideae

Mastoid antrum — antrum mastoideum

Parietal bone — os parietale

External surface — facies externa

Internal surface — facies interna

Groove for superior sagittal sinus — sulcus sinus sagittalis superioris

Squamous margin — margo squamosus

Sagittal margin — margo sagittalis

Parietal foramen — foramen parietale

Frontal margin — margo frontalis

Occipital margin — margo occipitalis

Frontal angle — angulus frontalis

Sphenoidal angle — angulus sphenoidalis

Occipital angle — angulus occipitalis

Mastoid angle — angulus mastoideus

Facial Skeleton — cranium viscerale

Maxilla — maxilla

Body of maxilla — corpus maxillae

Maxillary sinus — sinus maxillaris

Maxillary hiatus — hiatus maxillaris

Anterior surface — facies anterior

Infraorbital foramen — foramen infraorbitale

Canine fossa — fossa canina

Nasal notch — incisura nasalis

Orbital surface — facies orbitalis

Infraorbital groove — sulcus infraorbitalis

Infraorbital canal — canalis infraorbitalis

Anterior alveolar foramina — foramina alveolaria anteriora

Infratemporal surface — facies infratemporalis

Maxillary tuber — tuber maxillare

Posterior alveolar foramina — foramina alveolaria posteriora

Greater palatine groove — sulcus palatinus major

Nasal surface — facies nasalis

Conchal crest — crista conchalis

Frontal process — processus frontalis

Anterior lacrimal crest — crista lacrimalis anterior

Ethmoidal crest — crista ethmoidalis

Zygomatic process — processus zygomaticus

Alveolar process — processus alveolaris

Alveolar arch — arcus alveolaris

Dental alveoli — alveoli dentales

Interalveolar septa — septa interalveolaria

Interradicular septa — septa interradicularia

Alveolar juga — juga alveolaria

Palatine process — processus palatinus

Palatine grooves — sulci palatini

Palatine spines — spinae palatinae

Median palatine suture — sutura palatina mediana

Incisive foramen — foramen incisivum

Incisive canal — canalis incisivus

Nasal crest — crista nasalis

Nasal bone — os nasale

Ethmoidal sulcus — sulcus ethmoidalis

Zygomatic bone — os zygomaticum

Lateral surface — facies lateralis

Marginal tubercle — tuberculum marginale

Temporal surface — facies temporalis

Orbital surface — facies orbitalis

Zygomaticoorbital foramen — foramen zygomaticoorbitale

Zygomaticofacial foramen — foramen zygomaticofaciale

Zygomaticotemporal foramen — foramen zygomaticotemporale

Frontal process — processus frontalis

Temporal process — processus temporalis

Lacrimal bone — os lacrimale

Posterior lacrimal crest — crista lacrimalis posterior

Lacrimal hook — hamulus lacrimalis

Lacrimal groove — sulcus lacrimalis

Fossa for lacrimal sac — fossa sacci lacrimalis

Palatine bone — os palatinum

Horizontal plate — lamina horizontalis

Palatine surface — facies palatina

Palatine crest — crista palatina

Nasal surface — facies nasalis

Nasal crest — crista nasalis

Posterior nasal spine — spina nasalis posterior

Perpendicular plate — lamina perpendicularis

Greater palatine groove — sulcus palatinus major

Greater palatine canal — canalis palatinus major

Greater palatine foramen — foramen palatinum majus

Ethmoidal crest — crista ethmoidalis

Conchal crest — crista conchalis

Orbital process — processus orbitalis

Sphenoidal process — processus sphenoidalis

Sphenopalatine notch — incisura sphenopalatina

Pyramidal process — processus pyramidalis

Lesser palatine canals — canales palatini minores

Lesser palatine foramina — foramina palatina minora

Inferior nasal concha — concha nasalis inferior

Lacrimal process — processus lacrimalis

Maxillary process — processus maxillaris

Ethmoidal process — processus ethmoidalis

Mandible — mandibula

Body of mandible — corpus mandibulae

Base of mandible — basis mandibulae

Alveolar arch — arcus alveolaris

Dental alveoli — alveoli dentales

Interalveolar septa — septa interalveolaria

Interradicular septa — septa interradicularia

Alveolar juga — juga alveolaria

Mental protuberance — protuberantia mentalis

Mental tubercle — tuberculum mentale

Mental foramen — foramen mentale

Oblique line — linea obliqua

Mental spine — spina mentalis

Digastric fossa — fossa digastrica

Sublingual fossa — fovea sublingualis

Mylohyoid line — linea mylohyoidea

Submandibular fossa — fovea submandibularis

Ramus of mandible — ramus mandibulae

Masseteric tuberosity — tuberositas masseterica

Pterygoid tuberosity — tuberositas pterygoidea

Mandibular foramen — foramen mandibulae

Lingula of mandible — lingula mandibulae

Mandibular canal — canalis mandibulae

Mylohyoid groove — sulcus mylohyoideus

Coronoid process — processus coronoideus

Condylar process — processus condylaris

Mandibular notch — incisura mandibulae

Buccal crest — crista buccinatoria

HEAD of mandible — caput mandibulae

Neck of mandible — collum mandibulae

Pterygoid fossa — fovea pterygoidea

Vomer — vomer

Cuneiform part of vomer — pars cuneiformis vomeris

Choanal crest of vomer — crista choanalis vomeris

Wing of vomer — ala vomeris

Hyoid bone — os hyoideum

Body of hyoid bone — corpus ossis hyoidei

Greater horn — cornu majus

Lesser horn — cornu minus

Articulations of the skull bones

Suture — sutura

Serrate suture — sutura serrata

Squamous suture — sutura squamosa

Plane suture — sutura plana

Coronal suture — sutura coronalis

Sagittal suture — sutura sagittalis

Lambdoid suture — sutura lambdoidea

Dentomoalveolar syndesmosis (gomphosis) — qomphosis

Fontanelles — fonticuli

Anterior fontanelle — fonticulus anterior

Posterior fontanelle — fonticulus posterior

Sphenoidal fontanelle — fonticulus sphenoidalis

Mastoid fontanelle — fonticulus mastoideus

Skull synchondroses — synchondroses cranii

Temporomandibular joint — articulatio temporomandibularis

Lateral ligament — lig. laterale

Sphenomandibular ligament — lig. sphenomandibulare

Stylomandibular ligament — lig. stylomandibulare

Skull as a whole

Vertical view — norma verticalis

Basilar view — norma basilaris

Facial view — norma facialis

Occipital view — norma occipitalis

Lateral view — norma lateralis

Basion — basion

Opisthion — opisthion

Bregma — bregma

Vertex — vertex

Nasion — nasion

Inion — inion

Lambda — lambda

Asterion — asterion

Pterion — pterion

Calvaria — calvaria

Base — basis

External cranial base — basis cranii externa

Internal cranial base — basis cranii interna

Anterior cranial fossa — fossa cranii anterior

Middle cranial fossa — fossa cranii media

Posterior cranial fossa — fossa cranii posterior

Orbit — orbita

Nasal cavity — cavitas nasi

Superior nasal meatus — meatus nasalis superior

Middle nasal meatus — meatus nasalis medius

Inferior nasal meatus — meatus nasalis inferior

Oral Cavity — cavitas oris

Bony palate — palatum osseum

Temporal fossa — fossa temporalis

Infratemporal fossa — fossa infratemporalis

Pterygopalatine fossa — fossa pterygopalatina