CRANIUM THE SKULL o The skull is a

CRANIUM – THE SKULL o The skull is a head part of the skeleton. o It is made up of a number of fused flat bones. o It provides a protective cavity for the brain (cranial cavity) o It also houses some organs such as eyes, ears, nose and mouth o It has a defensive function by way of the horns o It contains many foramina, processus and small cavities (sinuses) for the protection, defensive and supporting function. Coto

CRANIUM – THE SKULL o The skull is formed by several articulated flat bones o The types of the joints between the bones are stationary sutura (except mandible and hyoid bone) o Some of the bones (pneumatic bones) also have an air cavity (sinus) for some vital functions o NEUROCRANIUM o VISCEROCRANIUM Coto

CRANIUM – THE SKULL o The skull is composed of two parts; - NEUROCRANIUM VISCEROCRANIUM (forms the cranial cavity) (supports the face) OS OCCIPITALE OS INTERPARIETALE OS FRONTALE OS ETHMOIDALE OS SPHENOIDALE OS TEMPORALE OS PTERYGOIDEUM VOMER - OS NASALE OS ROSTRALE OS LACRIMALE OS ZYGOMATICUM OS MAXILLARE OS INCISIVUM OS PALATINUM MANDIBULA OS HYOIDEUM Coto

NEUROCRANIUM o It forms the margins of the cranial cavity of the skull which houses brain. It has a roof, a floor, and walls (laterl, nasal, nuchal) like a box o Os occipitale o Os interparietale o Os frontale o Os ethmoidale o Os sphenoidale o Os temporale o Os pterygoideum o vomer Coto

OS OCCIPITALE o It is located on the nuchal wall of the skull. It encloses the foramen magnum which links the brain and spinal cord. o PARS BASILARIS Synchondrosis sphenooccipitalis Foramen lacerum (eq, su) Foramen jugulare (Car, ru) o PARS LATERALIS Condylus occipitalis Processus jugularis Canalis ni hypoglossi o SQUAMA OCCIPITALIS Crista nuchae (Car, eq, su) – Linea nuchae (ru) Protuberantia occipitalis externa (absent in Su) Coto

OS OCCIPITALE o It is located on the nuchal wall of the skull. It encloses the foramen magnum which links the brain and spinal cord. o PARS BASILARIS Synchondrosis sphenooccipitalis Foramen lacerum (eq, su) Foramen jugulare (Car, ru) o PARS LATERALIS Condylus occipitalis Processus jugularis Canalis ni hypoglossi o SQUAMA OCCIPITALIS Crista nuchae (Car, eq, su) – Linea nuchae (ru) Protuberantia occipitalis externa (absent in Su) Coto

OS INTERPARIETALE o It fuses with the parietal and occipal bones in adult o Processus tentoricus (Car, eq) o Tenterium cerebelli osseum o Tenterium cerebelli membranaceum Coto

OS PARIETALE o Tuber parietale o Crista sagittalis externa (eq ve car) o Planum nuchale (bo) o Planum parietale (ov, cap, su) o Planum temporale o Linea temporalis Coto

OS FRONTALE o SQUAMA FRONTALIS proc. cornualis (ru) protuberantia intercornualis (ru) proc. zygomaticus arcus orbitae lig. orbitale (Car, su) for. supraorbitale (Car’da yok) Sulcus supraorbitalis (ru) fossa glandulae lacrimalis o PARS ORBITALIS o PARS NASALIS Coto

OS ETHMOIDALE o It resembles a horizontally placed tube. o Lamina perpendicularis crista galli o Lamina cribrosa fossa ethmoidalis o Lamina tectoria o Lamina basalis o Lamina orbitalis Ethmoturbinalia Coto

OS TEMPORALE o The temporal bone is composed of squamous, petrosal and tympanic parts and forms the lateral wall of the cranial cavity. o It articulates with the mandible (art. temporomandibularis). o It consists of three parts; Pars squamosa, Pars petrosa, Pars tympanica Coto

Pars Squamosa o It has a cup-like basal part which is involved in the formation of the lateral wall of the cranial cavity. o Facies cerebralis o Facies temporalis Linea temporalis Fossa temporalis Proc. zygomaticus Fossa mandibulae Coto

Pars Tympanica o It is the retroventral part lying at the base of the skull. o Porus acusticus externus o Meatus acusticus externus o Bulla tympanica (Absent in man Oval-shaped in eq and ov, Spere-shaped in Car, Well-developed in bo and su) o Cavum tympani ***middle ear Coto

Pars Petrosa o It is the caudoventral part of the temporal bone. It locates at the inner surface. o Porus acusticus internus o Meatus acusticus internus o Proc. mastoideus (absent in su) o Proc. styloideus (Ru, eq) ***hyoid bone attaches*** o For. stylomastoideum (Canalis facialis) Coto

OS SPHENOIDALE It is an unpaired bone which forms the rostral part of the base of the cranial cavity. The shape of the bone like a wedge and it consists of two fused parts that are united synchondrosis intersphenoidalis at birth. OS PRESPHENOIDALE Ala orbitalis Corpus OS BASISPHENOIDALE Ala temporalis Corpus Proc. pterygoideus Coto

OS SPHENOIDALE o OS PRESPHENOIDALE Ala orbitalis crista orbitasphenoidale Corpus canalis opticus o OS BASISPHENOIDALE Ala temporalis for. lacerum (for. caroticum; Car) (for. ovale; Car, ru) Corpus fossa hypophysialis dorsum sellae sella turcica Proc. pterygoideus Coto

OS SPHENOIDALE ***Crista orbitasphenoidale for. ethmoidale (Car; forr. ethmoidalia) for. opticum fissura orbitalis (Car, eq) for. rotundum (Car, eq) for. orbitorotundum (Ru, su) for. alare orale (rostrale ) (Car, eq) for. alare aborale (caudale) (Car, eq) canalis alaris for. alare parvum (eq) Coto

OS PTERYGOIDEUM o It is a small paired bones at the base of the skull. It contrubutes the forming of the lateral wall of the choana. It takes the form of a flat bone which is situated between pterygoid process of sphenoid and perpendicular lamina of palatine bones Coto

OS VOMER o It is a long unpaired bone that extends the nasal cavity o sulcus vomeris o ala vomeris Coto

VISCEROCRANIUM The bones of the face surround the nasal and oral cavity. Facial bones can show great variety in shape among species (even if within species especially in dogs). o os nasale o os rostrale o os lacrımale o os zygomatıcum o os maxıllare o os ıncısıvum o os palatınum o mandıbula o os hyoıdeum Coto

OS NASALE o It forms the roof of the nasal cavity. o It is situated rostral to the frontal bone o Inc. nasoincisiva (eq, su, bo) (absent in car) o Inc. nasomaxillaris (ov) o Processus nasalis : tapered rostral end Eq, ov, su Bo, cap car Coto

OS LACRIMALE o It forms the rostral wall of the orbit. o Facies facialis Fossa lacrimalis externa (su, ov) o Facies orbitalis Fossa sacci lacrimalis (absent in su) Foramen lacrimale Foramina lacrimalia (su) Canalis lacrimalis Bulla lacrimalis (well-developed in ox) Coto

OS ZYGOMATICUM o Arcus zygomaticus : is formed by proc. temporalis of zygomatic bone and proc. zygomaticus of temporal bone o Processus temporalis and Processus frontalis (ru) o Crista facialis ( «S» shaped in ru) Coto

OS MAXILLA – Upper jaw o Upper jaw bone is the largest bone of the skull. o Corpus maxilla o Processus alveolaris is a longitudinal ridge projects ventrally o Processus palatinus is a horizontal plate-like part that forms the basis of the hard palate. Coto

OS MAXILLA The Body o Crista facialis o Tuber faciale (rum) o For. infraorbitale o Canalis infraorbitalis Coto

OS MAXILLA Alveolar process o Juga alveolaria is ridges formed by the roots of cheek teeth o Margo alveolaris is free border of the bone for alveols of teeth o Margo interalveolaris is a space without teeth o Tuber maxilla is caudal enlarged part of the bone o Fossa pterygopalatina I-For. maxillare II-For. sphenopalatinum III-For. palatinum aborale Coto

OS MAXILLA Palatine process o It forms both the floor of the nasal cavity and the roof of the oral cavity. o Caudally; it fuses with the palatine bone and in front; it forms the palatine fissure o Sutura palatina o For. palatinum majus o Canalis palatinus Coto

OS INCISIVUM o It forms the apex of the skull and participates in forming the hard palate. o Corpus ossis incisivi o Foramen incisivum (eq, car) o Fissura incisiva (ru, su) o o o Processus palatinus Fissura palatina Processus nasalis Inc. nasoincisiva Processus alveolaris Coto

OS PALATINUM o It is situated behind the maxilla. o Lamina horizontalis contrubutes to the formation of the hard palate o Lamina perpendicularis margins the lateral wall of the choana Coto

MANDIBULA The Lower jaw bone o Mandible is the lowest part of the skull. It holds the lower teeth and attaches the cranium with a movable joint (art. temporomandibularis) o The left and right bones are formed a rostral line (synchondrosis intermandibularis) by the fusion during mandibular development after birth o Spatium mandibulare is a space between two bones. The tongue fills the space in living animals * CORPUS MANDIBULAE * RAMUS MANDIBULAE Coto

MANDIBULA The Body o Facies labialis o Facies buccalis o Facies lingualis o Margo ventralis o Margo alveolaris o Alveoli dentales o Margo interalveolaris o Foramen mentale o Foramina mentalia (car, su) o Inc. vasorum facialium Coto

MANDIBULA The Arm o Processus muscularis ( proc. coronoideus ) o Processus articularis ( proc. condylaris ) o Caput mandibulae o Collum mandibulae o Incisura mandibulae o Fossa masseterica (Car) o Foramen mandibulae o Canalis mandibulae o Processus angularis (Car) Coto

OS HYOIDEUM o Hyoid bone is a seperate bone from the cranium like mandible. It attaches the styloid process (mastoid process in car. ) of the temporal bone and forms a slightly movable joint. The bone comprises several rod-shaped elements articulate with each other. o Basihyoideum Proc. lingualis o Thyrohyoideum o Ceratohyoideum o Epihyoideum o Stylohyoideum o Tympanohyoideum Coto