The skull of the dog

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Abstract

Fifty bones compose the skull of the dog

There are many variations in the shape of the skull amongst the different breeds of the dog. All the dogs were domesticated from wolves, from the late Paleolithic (about 14000 years ago), but different purposes led to different morphology. The canine breeds are grouped in 3 categories:

1.

Dolichocephalic: those breeds that have a long narrow head, like Greyhound, Afghan or Whippet.

2.

Brachycephalic: those breeds that have a short, strong head like Bulldog, Pekingese or Boston terrier. In some breeds, the lower jaw protrudes forwards, producing the condition known as “prognathism of the mandible”.

3.

Mesaticephalic: meaning skull of medium proportion, like Setter, Beagle or German Shepherd. Mesaticephalic is the nearest of the wolf size.

Fifty bones compose the skull of the dog. Those that close the brain form the cranial part (

cranium), while those in front of the skull build the facial part (facies).Latinis generally used to name the bones and other anatomical organs.

The bones of the cranial part

The basis of the skull

1. unpaired basioccipital (

pars basilaris ossis occipitalis)

2. unpaired basisphenoid & presphenoid bone (

os basisphenoidaleet os presphenoidale)

The back of the skull

1. unpaired supraoccipital bone (

squama* occipitalis)

2. paired exoccipital (

partes laterales)

The sides of the skull

1. paired temporal bones (

os temporale)

The roof of the skull

1. paired frontale bone (

os frontale)

2. parietal bone (

os parietale)

3. unpaired interparietal bone (

os interparietale)

The wall that separates the cranial from the facial part

1. unpaired ethmoid bone (

os ethmoidale)

The bones of the facial part

Lesser jaw
Mandibula
Nasal cavity-lateral walls

1. Paired

os lacrimale

2. Paired

os zygomaticum

3. Paired

osmaxilla

4. Paired

os incisivum

Nasal cavity- floor (= roof oral cavity)

1. Paired

os palatinum

2. Paired

os maxilla

3. Paired

os incisivum

4. unpaired

Vomer

Nasal cavity
os conchae nasalis ventralis
Nasal cavity- roof

1. Paired

Os frontale

2. Paired

Os nasale

Pharyngeal cavity – roof & walls

1. Paired

os pterygoideum

2. unpaired

os vomer

3. Paired o

s palatinum

4. Paired o

s sphenoidale

Openings

Openings are situated at the basis and the different sides of the skull. They permit the passage of nerves and blood vessels from and to the brain. Here is the list of the more important: here some pictures and a table indicating the transmitted structures

n = nerve, v = vein, a = artery

Openings Bones – os Transmitted structures
Foramen magnum Occipitale Spinal cord
Canalis hypoglossi Occipitale Hypoglossus n.Condylar v. & a.
Canalis opticus Praesphenoidale (ala) Optic n
Fissura orbitale Presphenoidale Ophthalmic n., III, IV, VI n.
Foramen rotundum Basisphenoidale (ala) Maxillary n.
Foramen alare caudale Basisphenoidale -pterygoideus Maxillary a.
Foramen alare rostrale Basisphenoidale-pterygoideus Maxillary a.
Foramen ovale Basisphenoidale (ala) Mandibular n.
Sulcus caroticus Basisphenoidale (corpus) Internal carotid n.
Foramen spinosum Basisphenoidale (ala) Trochlear n.; mid. Meningeal a.
Foramina ethmoidalia Frontale Ethmoid n. & v. & exter. Ethmodal a.
Incisura jugularis Temporale IX, X, XI n; internal carotid a.
Fissura petro-occipitale Temporale / occipitale Chorda tympani; greater petrosal n.
Foramen retroarticulare Temporale -squamosa Emissary v. for temporal sinus
Meatus acusticus internus Temporale – pars petrosa Facial n, cochlear n, vestibular n.
Foramen stylomastoideum Temporale- pars petrosa Facial n.
Foramen maxillare Maxilla Infraorbital n, v, a
Foramen infraorbitale Maxilla Infraorbital n, v, a
Foramen sphenopalatinum Palatinum Caudal nasal n, sphenopalatine v & a
Foramen palatinum caudale Palatinum Greater palatine n., v & a
Foramen lacrimale Lacrimale Drain of tears
Foramen palatinum majus Palatinum – L. horizontalis Greater palatine n.
Foramen mandibulae Mandibula Mandibular n., v & a
Foramen mentale Mandibula Mental n., v & a

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