The interactive dog atlas · for the classroom
50 cards, six per A4 sheet, to cut along the lines. Choose the set and, if you want an exercise, hide the name (the student writes it) or the text (the student writes the definition). No student names, no score.
caput · head
The head comprises the skull, ears, eyes, muzzle and mouth. Its shape and size vary a lot between breeds, from the long muzzles of sighthounds to the short ones of brachycephalic breeds. Inside sit the brain and the sense organs; the bones of the head can be seen in the skeleton layer, as "skull" and "mandible".
Where: From the nose leather to the nape, including the ears.
rostrum · muzzle
The muzzle is the portion of the head in front of the eyes: the nose, the upper jaw and the mandible with the lips. Its length relative to the skull is one of the criteria breed standards use to describe the head. Inside the muzzle is the nasal cavity with the nasal turbinates, covered by the mucosa through which the dog perceives scents.
Where: The front part of the head, from the stop to the nose leather.
planum nasale · nose
The nose leather is the tip of the nose: the moist, hairless skin with the two nostrils. Through the nostrils, air enters the nasal cavity, where the nasal turbinates and the olfactory epithelium are. Scent is detected through the olfactory epithelium and the olfactory nerves; the vomeronasal organ is an additional pathway for chemical detection.
Where: The tip of the muzzle, the hairless skin around the nostrils.
oculus · eye
The eyes sit in the orbits, the cavities of the skull that you can see in the skeleton layer as a circle. Their position, more lateral or more frontal, differs between breeds and influences the visual field. The eye is part of the sensory nervous system: the receptors in the retina send signals to the brain through the optic nerve.
Where: On the sides of the head, in the orbits, above the stop.
auris · ear
The external ear, the pinna, can be erect, semi-erect or drop, depending on the breed. It directs sound toward the ear canal and the middle and inner ear, which lie inside the skull. The pinna is also a communication tool: ear position is part of the dog's body language.
Where: On the top of the head, behind the eyes.
cranium · skull
The skull protects the brain and the sense organs and forms the face: the orbits in which the eyes sit, the nasal cavity with the turbinates and the maxilla with the upper teeth. It is made of several bones joined by sutures. The mandible articulates with the temporal bone at the temporomandibular joint.
Where: The bones of the head, without the mandible.
mandibula · mandible
The mandible is the bone of the lower jaw. It carries the lower teeth and articulates with the temporal bone of the skull at the temporomandibular joint, the one that allows the mouth to open and close. Its length relative to the maxilla determines how the lower teeth sit against the upper ones, that is, the occlusion.
Where: The bone of the lower jaw, articulated with the skull at the temporomandibular joint.
musculus temporalis
The most massive muscle of the head in carnivores, thick and elastic. It arises from the temporal fossa (and from the sagittal crest) and inserts by a tendinous sheet on the coronoid process of the mandible. It closes the mouth, so it bites, and it guards the temporomandibular joint against forward luxation.
Where: On the sides of the skull, in the temporal fossa, from above the eye to the nape.
musculus masseter
It arises from the lower edge of the zygomatic arch and inserts on the lateral face of the mandible (the masseteric fossa). It raises the mandible, that is, closes the mouth; together with the temporalis it gives the bite its force. The only masticatory muscle that opens the mouth is the digastricus, on the underside of the jaw.
Where: On the cheek, between the zygomatic arch and the mandible.
orbita
In the dog the bony rim of the orbit is incomplete laterally: the circle is closed by the orbital ligament, which runs from the zygomatic process of the frontal bone to the zygomatic arch. The orbit holds the eyeball, the seven extraocular muscles of domestic mammals (four recti, two obliques and the retractor) and the gland of the third eyelid.
Where: The bony cavity of the eye.
arcus zygomaticus
Formed by the union of the zygomatic process of the temporal bone with the temporal process of the zygomatic bone. It bounds the temporal fossa laterally, where the temporalis muscle lies, and the masseter arises from its lower edge. In brachycephalic breeds the arches are wide.
Where: The cheekbone, below the eye, from the orbit to the jaw joint; easily felt under the skin.
articulatio temporomandibularis
The joint between the mandibular fossa of the temporal bone and the condylar process of the mandible; it allows the mouth to open and close. The temporalis muscle guards it against forward luxation. It can be felt under the skin, in front of the ear, when the dog opens its mouth.
Where: The jaw joint, below the ear, behind the zygomatic arch.
bulla tympanica
A rounded bony swelling of the tympanic part of the temporal bone, large in carnivores. It encloses the ventral part of the middle ear cavity, with the eardrum and the three ossicles; from here the inner ear begins, with the cochlea and the vestibular labyrinth (hearing and balance).
Where: Under the skull, behind the jaw joint.
protuberantia occipitalis externa
A median prominence at the junction of the interparietal bone with the occipital bone; in the dog and the horse it corresponds to the highest point of the skull. The nuchal crest is its transverse extension. A palpable landmark used when measuring the length of the skull.
Where: The rearmost point of the skull, at the nape; easily felt under the skin.
crista sagittalis externa
Present in carnivores, it varies greatly between breeds; part of the temporalis muscle arises from it. The more developed it is, the more attachment surface there is for the biting muscles.
Where: The ridge along the middle of the skull, between the two temporal fossae, up to the occipital protuberance.
larynx · larynx
The larynx is the cartilaginous box at the start of the trachea: the epiglottic, thyroid and cricoid cartilages form its wall, and the intrinsic muscles (for example the cricothyroideus) move its parts. It is suspended from the hyoid apparatus, to which the hyoid muscles attach: the sternohyoideus, thyrohyoideus and mylohyoideus.
Where: At the entrance to the trachea, below the pharynx, suspended from the hyoid apparatus.
encephalon · brain
The brain lies in the cranial cavity, behind the orbits, protected by the bones of the neurocranium; together with the spinal cord it forms the central nervous system, while the cranial and spinal nerves form the peripheral system. According to UMN, the hemispheres have frontal, parietal, temporal and occipital lobes, with the rhinencephalon underneath: the olfactory bulb, tract and piriform lobe. In the drawing it is schematic; the path of scent is in “Journey of a Scent”.
Where: In the cranial cavity, protected by the neurocranium.
medulla spinalis · spinal cord
The spinal cord continues the brain through the foramen magnum and runs down the vertebral canal, protected by the vertebral arches; from it the spinal nerves leave for the trunk and the limbs. Together with the brain it forms the central nervous system. In the drawing it is the violet line below the crests of the vertebrae, drawn schematically.
Where: In the vertebral canal, from the foramen magnum backward, below the crests of the vertebrae.
glandula thyroidea · thyroid gland
The thyroid has two long, narrow, flattened lateral lobes, lying on the lateral faces of the trachea, close to the larynx, along the first six or seven tracheal rings. The isthmus joining them is inconstant: in large dogs it may be a glandular band about a centimeter wide, in small ones it is usually absent. The parathyroids, usually four, lie on the lobes.
Where: On the sides of the trachea, immediately behind the larynx, along the first 6-7 tracheal rings.
frons · forehead
The forehead is the region over the frontal bone, between the eyes and the crown, continued toward the nose by the bridge of the nose. In the dog, the frontal parts of the two bones form a central depression and slope forward, toward the stop. Under the skin lie the frontalis muscle, weak in the dog, and the bundles of the levator nasolabialis, which start here toward the upper lip.
Where: Above the eyes, on the frontal bone, between the stop and the crown.
no anatomical term · stop
The stop is the depression between the eyes, where the nasal bones meet the skull. It is a term from the show-ring vocabulary, defined by the Kennel Club glossary, not from anatomical nomenclature: the anatomy pages consulted do not use it. Anatomically, the area corresponds to the junction of the nasal bones with the frontal bone, where the frontals form a central depression.
Where: The step between the forehead and the bridge of the nose, between the eyes.
bucca · cheek
The cheek is the lateral wall of the mouth. It has a masseteric part, firm, over the masseter muscle, and a buccal part, mobile, toward the corner of the mouth, whose foundation is the buccinator muscle. In the dog the cheeks are loose and roomy, with a smooth, often pigmented mucosa. The duct of the parotid gland crosses the cheek and opens opposite the upper teeth.
Where: The lateral wall of the mouth, from the corner of the lips to below the ear.
labium superius / inferius · lips
The lips border the opening of the mouth. In the dog they are thin and mobile, with numerous tactile hairs; the upper lip is larger than the lower one, which it covers, and the edges of the lower lip are flaccid and serrated. “Flews” is the show-ring word for the pendulous upper lips of some breeds. In their thickness lies the orbicularis oris, supplied by the facial nerve.
Where: Around the opening of the mouth; the corner of the mouth reaches the level of the cheek teeth.
mentum · chin
The chin is the fleshy prominence below the lower lip, at the tip of the mandible. In animals it is far less marked than in humans. From here, on the inner side, start the muscles that pull the tongue forward: the genioglossus, “from chin to tongue”, and the geniohyoideus. The mental tactile hairs also sit on the chin.
Where: Below the lower lip, at the tip of the mandible.
nares · nostrils
The nostrils are the external openings of the nasal cavity, set in the planum nasale, the bare skin of the nose leather. In the dog each nostril is comma-shaped, with the wide part next to the septum and the narrow tail pointing backward and outward, into a groove, the alar groove, barely marked in carnivores. The upper edge, the wing of the nostril, is convex and mobile; the levator nasolabialis pulls on it.
Where: The two openings of the nose, in the planum nasale of the nose leather.
pili tactiles · tactile hairs, vibrissae
Vibrissae are thick, richly innervated hairs that serve the sense of touch. In the dog six groups are confirmed: above the eyes, on the upper lip (the whiskers), on the lower lip, on the chin, on the cheeks and in the zygomatic region, plus microvibrissae on the lips. Touching the ones above the eyes or the whiskers triggers a reflex blink; the dog pushes its whiskers forward when exploring an object.
Where: On the upper and lower lip, on the cheeks, on the chin and above the eyes.
palpebrae · eyelids
The eyelids are mobile folds that protect the eye; their middle layer contains the fibers of the orbicularis oculi. In carnivores, the lower eyelid has no cilia. In the corner toward the nose sits the third eyelid, the nictitating membrane, supported by a T-shaped cartilage: its movement is passive, it is pushed across the cornea when the retractor muscle pulls the eyeball back; humans have neither a third eyelid nor this muscle.
Where: Around the opening of the eye; the third eyelid in the corner toward the nose.
m. orbicularis oris · orbicularis oris
The orbicularis oris lies in the thickness of the lips, around the opening of the mouth, with no attachment to bone. In carnivores, the part in the upper lip is interrupted on the midline by a raphe, and in the dog the muscle is weakly developed. Each half is supplied separately by the facial nerve of its own side. The platysma, the cutaneous muscle of the neck, usually attaches to it.
Where: In the thickness of the lips, around the opening of the mouth.
m. levator nasolabialis · levator nasolabialis
The levator nasolabialis starts broadly from the frontal and nasal bones, in the dog also from the upper edge of the maxilla, and runs down under the skin to the upper lip and the wing of the nostril. It lifts the upper lip, pulling it laterally, and pulls on the wing of the nostril. In carnivores it is very broad and without clear limits. Its motor nerve is the dorsal buccal branch of the facial nerve.
Where: From the forehead and the nasal bones, past the orbit, to the upper lip and the wing of the nostril.
m. buccinator · buccinator
The buccinator is the flat muscle of the cheek, stretched parallel to the axis of the mouth; its molar part arises from the maxilla, above the cheek teeth. In the dog it is broad and very thin, with two planes of crossed fibers. It pulls the corner of the mouth backward and laterally and keeps the food between the teeth. It is supplied by the buccal branches of the facial nerve, mainly the dorsal one.
Where: In the cheek, parallel to the axis of the mouth, between the masseter and the corner of the lips.
m. orbicularis oculi · orbicularis oculi
The orbicularis oculi surrounds the opening of the eye; its fibers form the middle, fibromuscular layer of the eyelids and lie next to the tarsus. In the dog, the cutaneous muscle of the face sends a layer toward the lower eyelid that merges with the orbicularis, the malaris muscle. It is supplied by the facial nerve, through the zygomatic branch, the one serving the eyelids and the region of the nose.
Where: In the eyelids, around the opening of the eye.
m. digastricus · digastricus
The digastricus arises from the paracondylar process of the occipital bone and inserts on the ventromedial edge of the mandible. It opens the mouth: when the masticatory muscles relax, it pulls the mandible down. It has two bellies, with different nerve supply, from the trigeminal and from the facial nerve. In Sisson's old nomenclature it appears as the occipitomandibularis, with the same attachments.
Where: From the base of the skull, behind the ear, to the lower edge of the mandible.
mm. auriculares · auricular muscles
The auricular muscles are the small groups of muscles that move the pinna: the rostral group, which contains the scutiform cartilage, a flat plate in front of the ear, and the caudal group. Sisson lists in the dog the scutularis, the anterior auricular muscles, the helicis, the antitragicus and the parotidoauricularis. All are supplied by the facial nerve, which serves the superficial muscles of the head and of the external ear.
Where: Around the base of the ear, with the scutiform cartilage in the front group.
os nasale · nasal bone
The nasal bones, paired, form the upper part of the roof of the nasal cavity. They articulate with each other on the midline, laterally with the maxillae and caudally with the frontal bone. In the dog, in most breeds, they are long and wider in front, their rostral ends form an almost semicircular nasal notch, and their outer surface has a central groove. The front part of the dorsal nasal concha attaches to them.
Where: The roof of the nasal cavity, on the bridge of the nose; paired.
os incisivum · incisive bone (premaxilla)
The incisive bone, or premaxilla, lies at the rostral end of the head and carries the upper incisors. In the dog its body is flattened dorsoventrally, with three alveoli that grow from the first to the third incisor, and it completes the alveolus of the canine. The nasal process forms the lateral edge of the bony nasal opening, the palatine process the front of the hard palate. Behind the incisors open the canals to the vomeronasal organ.
Where: The bony tip of the muzzle; carries the upper incisors.
maxilla · maxilla
The maxilla is the largest bone of the face and carries the upper premolars, molars and canine. In the dog it is short but very tall at the back, without a facial crest; the infraorbital foramen, through which the infraorbital nerve emerges toward the lip and the nose, lies above the third premolar, and the infraorbital canal is short. The ventral nasal concha attaches to its surface facing the nasal cavity.
Where: The facial bone above the upper teeth, in front of the orbit.
os frontale · frontal bone
The frontal bone, paired, forms the base of the forehead region: the nasal and orbital parts belong to the face, the squamous part to the roof of the skull. In the dog, the supraorbital process is very short, so the upper edge of the orbit is incomplete, as in the pig, and is closed by the orbital ligament. The frontal sinus, divided into compartments in the dog, is hollowed out in this bone, above the lateral masses of the ethmoid.
Where: The base of the forehead: above the orbits, between the nasal and the parietal bones.
os parietale · parietal bone
The parietal bones, joined on the midline, form most of the roof of the cranial cavity; they lie above the temporal bone, between the frontal and the occipital bone. In the dog, where the two bones meet, a prominent parietal crest rises and continues onto the frontals: the sagittal crest of the skeleton layer, to which the temporalis muscle attaches.
Where: The roof of the braincase, between the frontal and the occipital bone.
os occipitale · occipital bone
The occipital bone closes the skull at the back and articulates with the first cervical vertebra, the atlas, through its two condyles. In the dog, the basilar part is wide and flat, and the nuchal crest, its peak, projects strongly backward in large breeds: it is the external occipital protuberance you feel at the nape. From it arise the digastricus and part of the muscles of the nape.
Where: The back end of the skull, where the atlas attaches.
os temporale · temporal bone
The temporal bone forms the lateral region of the skull and houses the organs of hearing. Its parts, petrous, tympanic and squamous, fuse early in the dog. The zygomatic process curves widely outward and forms the back part of the zygomatic arch; the external acoustic meatus is wide and very short, and the bony bulla is very large, round and smooth. The mandible articulates on it.
Where: The lateral part of the skull, around the ear, with the tympanic bulla.
os zygomaticum · zygomatic bone
The zygomatic bone, also called the malar, is a flat bone of the face that forms the lateroventral edge of the orbit and the front part of the zygomatic arch; its temporal process joins the zygomatic process of the temporal bone. In the dog, the zygomatic process is very long and strongly curved, and the frontal process, to which the orbital ligament attaches, completes the orbit, which is open laterally in carnivores.
Where: The cheekbone, below the orbit; the front part of the zygomatic arch.
apparatus hyoideus · hyoid apparatus
The hyoid apparatus is a chain of small bones that supports the tongue and the larynx, set in the back of the space between the bodies of the mandible; it attaches dorsally to the styloid processes of the temporal bones, ventrally to the larynx and the root of the tongue. Its pieces: basihyoid, thyrohyoid, ceratohyoid, epihyoid and stylohyoid; in the dog the stylohyoid is slightly longer than the epihyoid. The muscles of the tongue and neck attach to it.
Where: Between the rami of the mandible, attached above to the temporal bone, below to the larynx.
cerebellum · cerebellum
The cerebellum lies in the caudal part of the cranial cavity, above the brainstem, to which it is joined by peduncles; it has a median vermis and two hemispheres, with a surface furrowed into folia. It coordinates movement and balance. In awake dogs scanned with fMRI, its activation rose with the concentration of the odor; the authors link it to the control of sniffing and to the detection threshold.
Where: In the back part of the braincase, behind the hemispheres, above the brainstem.
truncus encephali · brainstem
The brainstem joins the hemispheres to the spinal cord; in the UMN nomenclature it includes the diencephalon, mesencephalon, pons and myelencephalon. Most cranial nerves leave through it, and the motor and sensory pathways of the body pass through it. The tractography of Andrews et al. (2022) described in the dog a ventral tract running from the olfactory bulb, along the base of the brain, into the brainstem; its function is not demonstrated.
Where: Below the cerebellum, between the hemispheres and the spinal cord.
bulbus olfactorius · olfactory bulb
The olfactory bulb is the ventral structure of the hemisphere, part of the rhinencephalon, resting on the cribriform plate of the ethmoid, through which the olfactory nerves enter; the olfactory peduncle attaches it to the brain. Here the axons of the neurons from the nose synapse in glomeruli with the mitral cells, whose axons leave through the olfactory tract. In the dog it takes up about 0.31 % of brain volume, measured on five fixed brains (Kavoi and Hassanali 2011).
Where: At the front end of the brain, below the frontal lobes, on the cribriform plate.
hypophysis · hypophysis (pituitary)
The hypophysis, the pituitary gland, hangs from the ventral face of the hypothalamus by an infundibulum and sits in the hypophyseal fossa on the dorsal face of the basisphenoid, on the floor of the cranial cavity. In the dog it is circular and rather small, and the fossa is shallow. It releases hormones that command the thyroid, the adrenals and the gonads.
Where: Below the brain, in the hypophyseal fossa of the base of the skull.
lingua · tongue
The tongue has a root, a body and an apex and lies on the floor of the mouth, attached to the hyoid apparatus by the hyoglossus and to the chin by the genioglossus. In the dog it is wide and thin in front, thicker toward the root, very mobile, unpigmented, bright red, with a median groove; on its underside, beneath the mucosa, lies the lyssa, a fibrous cord peculiar to carnivores. Taste from the front two thirds travels through the facial nerve.
Where: On the floor of the mouth, between the rami of the mandible, attached to the hyoid and to the chin.
glandula parotidea · parotid gland
The parotid gland lies in the retromandibular region, between the ramus of the mandible, the base of the ear and the superficial part of the masseter; its upper end is wide and notched by the base of the ear. The parotid duct crosses the masseter and opens into the mouth, opposite the upper cheek teeth. The sources do not agree on its size relative to the mandibular gland, so the atlas does not compare them.
Where: At the base of the ear, between the ramus of the mandible and the masseter.
glandula mandibularis · mandibular gland
The mandibular gland, called submandibular in humans, lies ventrocaudal to the parotid, in a fibrous capsule, in the angle between the jugular vein and the facial vein, where it can be palpated. It is round and yellowish; its duct runs forward, toward the floor of the mouth. Next to it, in the same capsule, lies the caudal part of the sublingual gland.
Where: Below and behind the angle of the mandible, next to the jugular vein.
lymphonodi mandibulares · mandibular lymph nodes
The mandibular lymph nodes lie near the angle of the mandible, in the caudal half of the region between the two rami of the jaw, separated from the skin only by the platysma; they drain the regions of the face. They are easy to palpate, especially when inflamed, and belong to the mandibular lymph center, a constant group in carnivores.
Where: Below the angle of the mandible, immediately under the skin.