Unit 3 (Hind limb vas/nerves and head/nervous system) Flashcards
Where does the external iliac artery arise from the aorta?
Level of the 6th or 7th lumbar vertebrae.
Vascular lacuna
The point at which the external iliac crosses the abdominal wall and becomes the femoral artery (medial circumflex femoral a. also passes here)
Located in the aponeurosis of the external abdominal oblique (also called the inguinal ligament).
Caudal gluteal artery
Larger of two terminal branches of the internal iliac a. (other is internal pudendal)
Gives off cranial gluteal artery and iliolumbar artery.
Cranial gluteal artery
From the caudal gluteal artery.
Supplies the middle and deep gluteal mm.
Iliolumbar artery
From the caudal gluteal artery.
Supplies the psoas major, iliopsoas, sartorius, tensor fasciae latae, and middle gluteal mm.
Deep femoral
Only branch of the external iliac
To the pudendoepigastic trunk and the medial circumflex femoral a.
Pudendoepigastric trunk
Gives rise to the caudal epigastric artery and the the external pudendal artery.
Caudal epigastric artery
Branch of the deep femoral
Supplies the ventral surface of the abdominal wall.
Mainly rectus abdominis and oblique, transversus abdominalis.
External pudendal artery
Passes through the inguinal canal and supplies the external prepuce.
What muscles bound the femoral triangle?
Sartorius
Vastus medialis/rectus femoris
Pectineus/adductor
Medial circumflex femoral artery
Continuation of the deep femoral and leaves the abdomen in the vascular lacuna.
Deep branch
Transverse branch
Deep branch of the medial circumflex femoral a.
Smaller of the two branches.
Supplies adductor and vastus medialis mm.
Transverse branch of the medial circumflex femoral a.
Larger of the two branches.
Supplies semimembranosus m.
Femoral artery
Continuation of the external iliac a. Branches: Superficial circumflex iliac a. Lateral circumflex femoral a. Proximal caudal femoral a. Saphenous a. Descending genicular a. Middle caudal femoral a. Distal caudal femoral a. Terminates in the popliteal artery.
Superficial circumflex iliac. a.
Supplies sartorius, tensor fasciae latae, and the rectus femoris.
Lateral circumflex iliac a.
Supplies all four head of the quadriceps, tensor fasciae latae, superficial and middle gluteals, and the hip joint.
Proximal caudal femoral a.
Supplies pectineus, adductor, and gracilis.
Saphenous a.
Medial side of the leg only.
Supplies the skin on the medial side of the stifle.
Terminates in a cranial and caudal branch.
Descending genicular a.
Supplies the medial stifle
Arises at approximately the same level of the saphenous and the middle caudal femoral a.
Middle caudal femoral a.
Supplies adductor and semimembranosus mm.
Distal caudal femoral a.
Supplies biceps femoris, semimembranosus, semitendinosus, gastrocnemius, and the digital flexors.
Popliteal a.
Termination of the femoral a.
Supplies the stifle, gastrocnemius, and popliteus mm.
Terminates as the cranial and caudal tibial aa.
Lateral saphenous vein
Not paired with an artery
Used for venipuncture in the dog.
Terminates in the distal caudal femoral vein .
Cranial branch of the saphenous artery.
Supplies flexor surface of the tarsus and terminates in the dorsal common digital arteries.
Caudal branch of the saphenous artery
Supplies tarsus and the deep structures of the metatarsus. Terminates in the deep plantar arch supplying the plantar metatarsals.
Cranial tibial artery
Underneath the cranial tibial m.
Supplies the fibulas longus, the long digital extensor, and cranial tibial mm.
Lumbosacral plexus
Diffuse and consists of the ventral branches of lumbar and sacral spinal nerves (mainly somatic nerves)
Nerves L1 - S3 can contribute
L1-L3 innervate mainly abdominal wall
L4-S3 innervate the hindlimb.
Obturator nerve
Runs through the obturator sulcus of the obturator foramen.
Innervates: adductor muscles of the limb (external obturator, pectineus, gracilis, and the adductor).
Femoral nerve
Emerges from the iliopsoas muscle and follows the femoral a.
Supplies iliopsoas and the quadriceps mm.
Saphenous nerve
Branches off the femoral nerve inside the ilopsoas. Innervates the sartorius, medial side of the leg and paw.
Cranial gluteal nerve
Branch from the lumbosacral trunk.
Runs with the cranial gluteal artery to innervate the tensor fasciae late, middle, and deep gluteal mm.
Caudal gluteal nerve
Branch from the lumbosacral trunk.
Runs with the caudal gluteal artery to innervate the superficial gluteal m.
Pudendal nerve
In the ischiorectal fossa Branches: Caudal rectal n. Perineal nn. Dorsal nerve of the penis/clitoris
Caudal cutaneous femoral nerve
Runs just superficially to the pudendal nerve.
Caudal rectal nerve
Innervates the external anal sphincter
Perineal nerves
Innervates the skin of the anus, perineum, muscles of the penis, vestibule, and vulva, and the scrotum or labia. Multiple heading caudally from the pudendal nerve.
Dorsal nerve of the penis
Medial nerve off the pudendal nerve.
Sensory to skin of the glans
Dorsal nerve of the clitoris
Medial nerve off the pudendal nerve.
Sensory to the clitoris.
Lumbosacral trunk
Origin of the sciatic, caudal gluteal, and cranial gluteal nerves near the ischiatic notch.
From the 6th/7th lumbar spinal nerves.
Sciatic nerve
Branch from the lumbosacral trunk.
Innervates the biceps femoris, semitendinosus, semimembranosus, internal obturator, gemelli, and quadratus femoris mm. with small branches as it passes.
Terminates in the common fibular and tibial nerves.
What is another name for the common fibular nerve?
Common peroneal nerve.
Common fibular nerve
Smaller branch of the sciatic
Deep and superficial branches
Eventually forms common digital nerves that innervate the paw.
Superficial fibular nerve
Caudal branch off the common.
Deep fibular nerve
Cranial branch off the common.
Innervates the cranial tibial, long digital extensor, and fibularus longus.
Dorsal pedal artery
Branch off of the cranial tibial artery.
Supplies the tarsus and terminates at the arcuate artery at the tarsometatarsal joint.
Arcuate artery
Gives off dorsal metatarsal arteries and runs through the ligaments of the foot to the plantar side.
Perforating branch of the arcuate artery
Branch that supplies the plantar side of the paw.
Tibial nerve
Larger branch of the sciatic nerve.
Passes between the two heads of the gastrocnemius m.
Supplies the extensors of the tarsus/flexors of digits, the gastrocnemius, the stifle, the popliteus, the superficial digital flexor, and both digital deep flexor mm.
Terminates in the medial and lateral plantar nerves.
Tarsal tunnel
Formed by the space between the sustentaculum tali, calcanean tuber, and flexor retinaculum.
Contains the tendon of the lateral digital flexor and its synovial sheath, medial and lateral plantar nerves, and the caudal branch of the saphenous a.
Medial and lateral plantar nerves
Off the tibial nerve, main innervation to the plantar surface of the hind paw.
Skull
Both bony and cartilaginous elements.
Cranium
Elements of the skull that surround the brain.
Calvaria
Elements of the skull that make up the roof (usually referred to as the dorsal cranium).
Parietal bone
Backmost bone of the dorsal skull.
Frontal bone
Middle bone of the dorsal skull between the zygomatic arches.
External sagittal crest
Formed on the midline of the skull by the parietal and interparietal bones.
Joins with the nuchal crest at the external occipital protuberance.
Lacking in bracheocephalic dog.
Interparietal bone
Unpaired bone
Appears to be a bony process off of the occipital bone (fuses prenatally), running between the median fusion of the parietal bone.
Temporal lines
Replaces the external sagittal crest in bracheocephalic dogs, running sagittally to the sagittal crest.
Meet the nuchal crest at two individual external occipital protuberances.
Nuchal crest
Transverse ridge that marks the transition between the caudal and dorsal surfaces of the skull.
Temporal bones
Lateral to the parietal bone. Made up of: Squamous part (Zygomatic process) Tympanic part (tympanic bulla) Petrous part (inner ear labyrinths, promontory, mastoid process)
Basisphenoid
Forms the middle of the ventral part of the cranium between the occipital and pre sphenoid parts.
Two wings on the lateral side of the skull, bear the alar canal.
Presphenoid
Forms a small medial spine on the ventral part of the cranium rostral to the basisphenoid bone.
Small wing on the lateral side of the skull that bears the optic foramen.
Nasal bone
Rostral dorsal bone. Paired.
Maxilla
rostral lateral bone bearing the cheek teeth. Part of the dorsum of the skull and the hard palate.
Incisive bone
Most rostral tip of the skull, ventral and dorsal. Bears the upper incisors.
Long nasal process to articulate with the maxilla.
Nasal aperture
Opening of the two nostrils between the nasal and incisive bones. More round in brachiocephalic breeds.
Orbit
Cavity in which the eye is situated, continuous with the zygomatic arch in the skull. Surrounded by orbital margin, orbital ligament, zygomatic salivary gland, pterygoid muscle, and temporal muscle.
Orbital margin
Bony part of the orbit Formed by: Maxillary bone Frontal bone Lacrimal bone Zygomatic bone
Orbital ligament
Closes the orbit in life
Superficial to the lacrimal gland.
Zygomatic arch
Formed by: Zygomatic process of the maxilla Zygomatic bone Zygomatic process of the temporal bone Origin of the masseter muscle
Pterygopalatine fossa
Located ventral to the orbit
Formed by the maxilla, palatine bone, and the zygomatic bone.
Optic canal
Passes through the presphenoid bone.
Bears: optic nerve
Orbital fissure
Formed by the articulation between the basisphenoid and presphenoid bones
Bears: oculomotor, trochlear, abducent, and ophthalmic nerves plus some vessels.
Rostral alar foramen
Passes through the basisphenoid bone
Rostral entrance into the alar canal
Bears: maxillary artery and maxillary nerve
Temporal fossa
Convex space on the parietal and temporal bones that is bounded by the sagittal line, nuchal crest, and the zygomatic process.
Caudal palatine foramen
Ventral foramen on the rostral part of the pterygopalantine fossa.
Bears the major palatine artery, vein, and nerve moving into the palatine canal to the hard palate.
Sphenopalatine foramen
Dorsal foramen on the rostral part of the pterygopalantine fossa.
Bears the sphenopalatine artery and vein and the caudal nasal nerve into the nasal cavity.
Maxillary foramen
Caudal opening of the infraorbital canal, found in the rostral portion of the zygomatic arch.
Bears the infraorbital artery, vein, and nerve
Alveolar canals
Found around the maxillary foramen for small nerves to the molars.
Fossa for the lacrimal sac
Dorsal to the maxillary foramen in the ventral part of the orbit.
Continues into the nasolacrimal canal.
Infraorbital foramen
Rostral opening of the infraorbital canal.
Dorsal to the 3rd premolar tooth.
Alveolar juga
Lateral elevations of the maxilla bone to allow space for the roots of the cheek teeth.
Paracondylar process
Ventral projection of the occipital bone lateral to the occipital condyles.
Articulates with the lateral part of the tympanic bulla.
Origin of the digastricus muscle.
Occipital bone
Forms the caudal part of the skull Four parts from prenatal bone fusion Basiocciptal bone Paired exoccipitals (bear the condyles) Supraoccipital bone
Tympanic bulla
Encloses the middle ear cavity and its ossicles.
Ear ossicles
Incus, Stapes, and Malleus
External acoustic meatus
Open portion on the lateral side of the tympanic bulla through which the promontory can be seen. Covered by tympanic membrane in life which is then surrounded by the annular cartilage of the external ear around the periphery.
Promontory
Barral shaped eminence on the ventral surface of the tympanic bulla.
Contains the vestibular and cochlear windows.
Cochlear window
End of the “barrel” of the promontory.
Closed in life by a membrane.
Vestibular window
On the dorsal side of the “barrel” of the promontory.
Contains the footplate of the stapes
Incus
One of three ear ossicles
Malleus
One of three ear ossicles
Stapes
One of three ear ossicles
Mastoid process
Only external part of the petrosal part of the temporal bone. Lies lateral to the paracondylar process.
Oval foramen
Entrance from the cranial cavity to the lateral side of the skull.
Bears the mandibular nerve from the trigeminal nerve.
Foramen lacerum
Rostromedial edge of the tympanic bulla.
Bears a loop of the internal carotid artery that courses rostrally through the carotid canal and entered the cavernous sinus on the floor of the cranial cavity.
Musculotubal canal
Lateral to the foramen lacerum and less visible.
Bears the auditory tube that connects the oral and nasal cavities
Tympano-occiptial fissure
Opening between the occipital bone and the tympanic part of the temporal bone.
Two parts: petro-occipital canal (ventral petrosal venous sinus) and carotid canal (internal carotid artery)
Hypoglossal canal
Caudomedial to the tympano-occiptal fissure
Bears the hypoglossal nerve
Caudal alar foramen
Caudal opening of the alar canal in the basisphenoid bone.
Round foramen
Opening from the cranial cavity into the alar canal. Bears the maxillary nerve from the trigeminal nerve. This will exit from the rostral alar foramen. 1
Mandibular fossa
Depression for articulation of the condylar process of the mandible on the zygomatic process of the temporal bone.
Retroarticular process
Caudal wall of the medial aspect of the mandibular fossa
Retroarticular foramen
Caudal to the retroarticular process
Bears the emissary vein
Stylomastoid foramen
Between the tympanic bulla and the mastoid process.
Bears the facial nerve
Interalveolar septae
Separate the alveoli of adjacent teeth
Interradicular septae
Separate the alveoli of teeth with multiple roots
Hard palate
Formed from the ventral horizontal parts of the incisive, maxilla, and palatine bones.
Palatine fissure
Two large holes in the incisive bone near the incisors.
Major palatine foramen
Medial to the fourth cheek tooth.
Bears branches of the major palatine artery, vein, and nerve.
Minor palatine foramina
Caudal to the major palatine foramen.
Bears branches of the major palatine artery, vein, and nerve.
Choanae
Openings of the right and left nasal cavities into the nasopharynx. Located at the caudal end of the hard palate where the vomer articulates with the palatine bones.
Basioccipital bone
Base of the caudal part of the foramen magnum and caudal part of the ventral surface of the cranium.
Foramen magnum
Large foramen that bears the medulla of the brain stem (continues as the spinal cord) and is surrounded by the occipital condyles.
Mandible
Compose the inferior jaw.
Join at the intermandibular articulation.
Has a body and ramus.
Body of the mandible
Horizontal part of the mandible.
Ramus of the mandible
Vertical part of the mandible.
Alveolar border of the mandible
Dorsal part of the mandible that bears the alveoli of the inferior teeth.
Masseteric fossa
Triangular fossa on the lateral side of the mandibular ramus.
Insertion for the masseter muscle.
Coronoid process of the mandible
Most dorsal part of the mandibular ramus.
Mandibular foramen
Caudal opening of the mandibular canal on the medial side of the mandible.
Mandibular canal
Bears the inferior alveolar artery and vein and inferior alveolar nerve
Mental foramina
Usually three, the rostral openings of the mandibular canal.
Allows the inferior alveolar nerve to innervate the chin and lower lip.
Condylar process of the mandible
Middle part of the mandibular ramus that articulates with the mandibular fossa as the temporomandibular joint.
Temporomandibular joint
Between the condylar process of the mandible and the mandibular fossa of the temporal bone.
Mandibular notch
Between the coronoid and condylar processes. U-shaped depression.
Bear the motor branches of the mandibular nerve that innervate the masseter muscle.
Angular process of the mandible
Most ventral part of the mandibular ramus.
Insertion for the temporal muscle.
Hooked in the dog.
Insertion of the pterygoid muscle on the medial side.
Bones of the hyoid apparatus
Tympanohyoid cartilage Stylohyoid Epihyoid Ceratohyoid Basihyoid Thyrohyoid
What is the molar/premolar status of the inferior and superior carnassials?
Superior = last premolar Inferior = first molar
Parts of the tooth
Crown, root, and neck
Cheek teeth
Molars and premolars
Dental formula of the adult dog
I 3/3 C 1/1 P 4/4 M 2/3 Total = 42 with 10/11 All = half, left or right
Dental formula of the young dog with milk teeth
I 3/3
C 1/1
P 3/3
Totatl = 28 with 7/7
Premolar carrying space
Between the premolars when the mouth is closed.
Surfaces of the teeth
Vestibular surface = lateral tooth surface
Lingual surface = inferior medial tooth surface
Palantine surface = superior medial tooth surface
Mesial contact surface: rostral side of the tooth
Distal surface: caudal side of the tooth
Occlusal/masticating suface: top of the tooth
Cribriform plate
Caudal wall of the ethmoid bone, rostral boundary of the cranial cavity.
Transmit blood vessels to the brain and olfactory nerves to the olfactory bulbs.
Holes = olfactory foramina
Rostral cranial fossa
Rostral to the optic canal.
Contains the olfactory bulbs of the brain and the rostral part of the frontal lobes.
Middle cranial fossa
Between the optic canal and the petrosal crest.
Contains most of the paired foramina of the cranial cavity. Rostral to caudal is:
Optic canal
Orbital fissure
Round foramen
Oval foramen
Contains the parietal and temporal lobes of the cerebrum.
Caudal cranial fossa
Between the petrosal crest and the foramen magnum.
Contains the cerebellum, the pons, and the medulla.
Ethmoid bone
Cribriform plate and the attached ethmoid labyrinth as well as the bony portion of the nasal septum and the orbital laminae.
Sella turcica
“Turkish saddle” composed of the hypophyseal fossa and the dorsum sellae.
Hypophyseal fossa
Small depression rostral to the dorsum sellae that contains the pituitary gland.
Dorsum sellae
Unpaired quadrilateral process in the middle cranial fossa.
Canal for the trigeminal nerve
In the tip of the petrosal process of the temporal bone
Trigeminal nerve will pass through this before breaking into three parts to pass through the foramina in the middle cranial fossa.
Internal acoustic meatus
Caudal to the canal for the trigeminal nerve
Contains the facial and vestibulocochlear nerve
Cerebellar fossa
Dorsocaudal to the internal acoustic meatus
Contains a small lateral portion of the cerebellum.
Jugular foramen
Between the petrosal temporal and the occipital bones inside the cranial cavity
Opens to the tympano-occipital fissure.
Contains the glossopharyngeal, vagus, and accessory cranial nerves and the sigmoid venous sinus.
Hypoglossal canal
Contains the hypoglossal nerve
Caudal to the jugular foramen and medial to the condyloid canal.
Tentorium osseum
Rostroventral projection of the caudal wall of the cranial cavity and bears the tentorium cerebelli.
Tentorium cerebelli
Connection of dural membrane between the petrosal processes and the tantrum osseum.
Separates the cerebrum from the cerebellum
Nasopharynx
Cavity just rostral to the chonae
Conchae
Turbinates, bony scrolls inside the nasal cavity. In life are covered by epithelium.
Dorsal nasal concha
Most dorsal scroll off of the cribriform plate. Extends as the shelf attached along the medial surface of the nasal bone.
Ventral nasal concha
Attach to a crest on the medal surface of the maxilla. In the middle of the nasal cavity but never contacts the median nasal septum.
Ethmoidal labyrinth
Attached to the cribriform plate. Very delicate and compose the fundus of the nasal cavity.
Ectoturbinates
Extension of the ethmoidal labyrinth into the rostral portion of the frontal sinus
Endoturbinates
Extension of the ethmoidal labyrinth to the vomer (which separates the labyrinth from the nasopharynx) and the presphenoid.
Nasal septum
Separates the right and left nasal cavities. Septal cartilage in the rostral 2/3, osseous part formed by the perpendicular plate of the ethmoid bone, septal processes of the frontal and nasal bones, and the sagittal potion of the vomer.
Septal cartilage
The cartilaginous portion of the nasal septum in the rostral 2/3. Articulates with cartilage at the nares that prevent collapse of the nostrils. Ventrally, fits into a groove formed by the vomer.
Dorsal nasal meatus
One of four passages through the concha. Between the nasal bone and the dorsal nasal concha.
Middle nasal meatus
One of four passages through the concha. Between the dorsal nasal concha and the ventral nasal concha.
Ventral nasal meatus
One of four passages through the concha. Between the ventral nasal concha and the hard palate.
Common nasal meatus
One of four passages through the concha. Vertical space on each side of the nasal septum where a nasal feeding tube may be passed.
Lateral frontal sinus
Largest of the sinuses and the only that has clinical relevance.
Occupies the zygomatic process and then extends caudally. Often has partial bony separations. Reaches from midline to the temporal line.
Rostral frontal sinus
Small between the median plane and the orbit.
Medial frontal sinus
Small between the median plane, rostral frontal sinus, and lateral frontal sinus.
Maxillary recess
Communicates with the nasal cavity with an opening through the rostral roots of the fourth superior premolar (carnassial). Continues caudally to the last molar tooth.
Lateral nasal gland
Occupies the rostral part of the maxillary recess. Duct opens into the dorsal vestibule. Secretions to prevent desiccation caused by nasal panting.
Articular disc of the temporomandibular joint
Thin cartilagenous disc that separates the articular surfaces of the temporal bone and mandible. Divides the joint capsule into two compartments.
Philtrum
The median grew separating the right and left parts of the superior lip. Incorrect fusion can cause a cleft lip here in fetal development.
Vestibule
The space in between the lips and the teeth/gums
Platysma
Attachments: dorsal median raphe of the neck and angle of the mouth.
Radiates into the orbicularis oris.
“Smiling” or panting muscle
Orbicularis oris
Extends from one lip to the other around the angle of the mouth.
Connects at the median plane in the incisor region at the median plane of each jaw.
Buccinator muscle
Thin wide muscle that forms the foundation of each cheek.
Attachments: alveolar margins of the mandible and maxilla and the buccal mucosa.
Other name for lips
Inferior and superior labia oris
Other name for cheeks
Buccae
Levator nasolabialis
Flat muscle attaching to the maxillary bone and edge of superior lip and nares.
Action: dilates the nostril and raises the superior lip.
Superior and inferior palpebrae
Top and bottom eyelids
Palpebral fissure
Gap between the eyelids
Medial and lateral palpebral commissures
Joining of the eyelids on either side of the palpebral fissure. Each attached by ligaments to the adjacent bone.
Medial and lateral palpebral ligaments
Attach the medial and lateral palpebral commissures to the adjacent bone. Medial is well developed and attaches to the frontal bone. Lateral is poorly developed and attaches to the zygomatic bone.
Palpebral conjunctiva
Mucous membrane on the inner surface of the eyelid.
Bulbar conjunctiva
Mucous membrane continuous with the palpebral conjunctiva on the globe of the eye
Fornix
Pocket formed between the bulbar and palpebral conjunctiva.
Conjunctival sac
Potential cavity formed by the fornix between the palpebral and bulbar conjunctiva
Lacrimal caruncle
Triangular prominence of finely furred skin at the medial commissure of the eye.
Lacrimal punctum
Beginning of the dorsal and ventral lacrimal ducts, a few millimeters from the medial commissure.
Lacrimal gland
Located ventral to the zygomatic process.
Secretes serous fluid through duct openings into the dorsolateral part of the conjunctival sac.
Goblet cells and tarsal glands also aid in forming tear secretion.
Lacrimal canaliculi
Collection of serous fluid from the lacrimal gland after it has passed over the cornea and was collected by the lacrimal puncta.
Lacrimal sac
Collection of the serous fluid from the lacrimal canaliculi.
Nasolacrimal duct
Moves the fluid from the lacrimal sac to the ventral nasal meatus where evaporation takes place.
Opens on the ventral aspect of the alar fold in the nose.
Plica semilunaris
Third eyelid
Concave fold of palpebral conjunctiva and cartilage protruding from the medial angle of the eye.
Surrounding by the superficial gland of the third eyelid and some lymphoid tissue.
Superficial gland of the third eyelid
Fat and glandular tissue surrounding the cartilage in the plica semilunaris. Secretes serous solution.
Orbicularis oculi
Lies in the eyelids.
Attached medially to the medial palpebral ligament.
Retractor anguli oculi lateralis
Covers the lateral palpebral ligament.
Closes the palpebral fissure
Levator palpebrae superioris
Arises deep within the orbit
Elevates the superior lid.
Rostral auricular muscles
Lie on the forehead caudal to the orbit and converge towards the auricular cartilage. Meet on the midline.
Scutiform cartilage
Boot-shaped cartilagenous plate in the muscles rostral and medial to the external ear. Isolated.
Caudal auricular muscles
Arise from the median raphe of the neck and attach directly to the auricular cartilage.
Oral cavity
Divided into the vestibule and the oral cavity proper.
Ducts of the zygomatic gland
Open into the vestibule lateral ago the last superior molar
Palatoglossal arch
Fold of tissue that extends from the body of the tongue to the beginning of the soft palate.
Mimetic muscles
Muscles of facial expression - many small superficial muscles of the face all innervated by the facial nerve.
Parts of the tongue
Root (caudal third)
Body (rostral to the body but still connected by the frenulum)
Apex (free extremity)
Filiform papillae
Found on the body and apex of the tongue
Tips directed caudally
Conical papillae
Replace the filiform papillae at the root of the tongue - one pointed tip.
Fungiform papillae
Smooth, rounded surfaces, fewer in number within both the filiform and conical papillae. Taste buds.
Foliate papillae
Lateral margins of the root of the tongue rostral to the palatoglossal arch. Taste buds.
Vallate papillae
Located at the junction of the body and root of the tongue.
4-6 in the dog arranged in the form of a V with apex directed caudally. Taste buds.
Lingual frenulum
Ventral fold of mucosa that attaches the tongue to the floor of the oral cavity.
Sublingual caruncle
Slightly raised part of the mucosa lateral to the rostral part of the frenulum and protrudes from the floor of the oral cavity.
Sublingual fold
Extends caudally from the caruncle.
Mandibular duct
Found in the sublingual fold.
Separate or common opening with the mandibular duct on the sublingual caruncle.
Major sublingual duct
Found in the sublingual fold. Separate or common opening with the mandibular duct on the sublingual caruncle.
Lyssa
Fusiform fibrous spicule that lies in the ventral part of the apex of the tongue.
Mandibular salivary gland
Large round gland on the side of the head between the maxillary and linguofacial veins. Covered by a thick capsule.
Sublingual gland
Caudal also included in the capsule of the mandibular salivary gland.
Parotid salivary gland
Lies between the mandibular gland and the ear. Roughly V-shaped.
Parotid lymph node
Small lymph node rostral to the parotid salivary gland.
Parotid duct
Formed by 2-3 covering radicles leaving the rostral border of the gland.
Runs across the masseter, leaving a groove on the muscle. Opens into the vestibule on a small papilla at the level of the caudal margin of the superior carnassial.
Zygomatic salivary gland
Medial to the zygomatic bone between the eyeball and the pterygoid muscle.
Incisive papilla
Small eminence located just caudal to the central incisor teeth.
Incisive duct
Fissure on either side of the incisive papilla that opens into the ventral nasal meatus.
Vomeronasal organ
Extends caudally from the incisive duct. Olfactory receptor for sexual stimuli or kin recognition. Very small and on the sagittal plane - does not exceed 1 mm thick and 2-3 cm long.
Oropharynx
Extends from the palatoglossal arches to the caudal border of the soft palate. Contains the palatine tonsil.
Palatine tonsil
Located caudal to the palatoglossal arches. Attached laterally to the palatine fossa.
Semilunar fold
Medial wall of the palatine fossa that folds over the palatine tonsil.
Nasopharynx
Extends from the chonae to the caudal end of the soft palate.
Palatopharyngeal arch
Folds that extend from the caudal end of the soft palate to the dorsolateral wall of the nasopharynx. Marks the end of the nasopharynx.
Auditory tube
Slitlike opening in the lateral wall of the nasopharynx dorsal to the soft palate.
Laryngopharynx
Dorsal to the larynx. From the palatopharyngeal arches to the beginning of the esophagus. Not a clear distinction between the oropharynx and the laryngopharyx.
Pharyngoesophageal limen
Annular constriction of soft tissue at the level of the cricoid cartilage, marking the beginning of the esophagus.
Pharyngeal muscles (8)
Cricopharyngeus Thyropharyngeus Hyopharyngeus Palatopharyngeus Pteryopharyngeus Stylopharyngeus Levator veli palatini Tensor veli palatini
Cartilages of the larynx
Epiglottic
Thyroid
Artenoid
Cricoid
Epiglottic cartilage
Unpaired. Most cranial of the laryngeal cartilages.
Lingual surface attached to the basihyoid bone.
Lateral margin attached by mucosa to the cuneiform process of the arytenoid process.
Attaches to the body of the thyroid process caudally.
Epiglottic fold
Formed from the mucosa between the the cuneiform process of the arytenoid cartilage to the lateral margin of the epiglottic cartilage.
Thyroid cartilage
Unpaired. Deep trough that surrounds the ventrolateral aspects of the other cartilages cranially.
Rostral cornu of the thyroid cartilage
Articulation with the thyrohyoid bone.
Caudal cornu of the thyroid cartilage
Articulation with the caudal aspect of the cricoid cartilage
Caudal thyroid incisure
Notch on the ventral side of the thyroid cartilage that holds the cricothyroid ligament.
Cricothyroid ligament
Connects the caudal border of the thyroid cartilage to the cranial border of the cricoid cartilage.
Cricoid cartilage
Unpaired. A complete ring on the ventral aspect of the larynx. Has a lamina (wide dorsal plate) and a narrow ventral arch. Has a caudolateral facet for articulation with the thyroid cartilage and a craniolateral facet for articulation with the with corniculate process of the arytenoid cartilage.
Arytenoid cartilage
Paired. Mainly within the cricoid cartilage.
Muscular process of the arytenoid cartilage
Lateral. Attaches to laryngeal musculature.
Vocal process of the arytenoid cartilage
Ventral. Attaches to the vocal fold.
Corniculate process of the arytenoid cartilage
Dorsal, articulates with the cricoid cartilage.
Cuneiform process of the arytenoid cartilage
Cranial. Attachement for the vestibular fold.
Vestibular fold
Attached between the cuneiform process of the arytenoid cartilage and the thyroid cartilage. Rostral fold of the laryngeal ventricle.
Vocal fold
Attached between the vocal process of the arytenoid cartilage and the midventral part of the thyroid cartilage. Caudal fold of the laryngeal ventricle.
Laryngeal ventricle
Diverticulum of the laryngeal mucosa bounded by the vocal and vestibular folds. Important in phonation.
Pharynx
Open spaces formed in the caudal part of the head from nose and mouth to larynx.
Larynx
Structure formed by the four laryngeal cartilages.
Glottis
Structure formed by the vocal folds, vocal processes of the arytenoid cartilages, and the rima glottidis.
Rima glottidis
Narrow passageway through the glottis. Size and shape modulated by muscular activity.
Cricothyroid muscle
Lies ventral to the insertion of the sternothyroideus over the cricoid cartilage and trachea. Indirectly tenses the vocal cords (increases pitch) by drawing the ventral parts of the cricoid and thyroid cartilages together.
Innervated by the cranial laryngeal nerve, a branch of the vagus.
Only laryngeal muscle seen best on the lateral side of the head.
Cricoarytenoideus dorsalis
Dorsolateral surface of the cricoid to the muscular process of the arytenoid cartilage. Rotates the arytenoid so that the vocal process moves laterally and opens the glottis. This is accomplished by pulling the muscular process caudomedially. Very important during heavy breathing.
Innervated by the caudal laryngeal nerve (off the recurrent laryngeal n.)
Dysfunction can cause exercise intolerance, “roaring,” laryngeal paralysis.
Cricoarytenoideus lateralis
Lateral surface of the cricoid cartilage to the muscular process of the arytenoid cartilage between the cricoarytenoidus dorsalis and the vocalis. Acts to close the glottis by pulling the muscular process ventrally and thus moving the vocal process medially.
Innervated by the caudal laryngeal nerve (off the recurrent laryngeal n.)
Disfunction causes increased likelihood of coughing/gagging/choking or aspiration pneumonia.
Thyroarytenoideus
Gives rise to the vocals medially and the ventricular rostrally. Internal midline of the thyroid cartilage to arytenoid cartilage. Relaxes the vocal fold (deepens pitch) and constricts the glottis.
Innervated by the caudal laryngeal nerve (off the recurrent laryngeal n.)
Vocalis
Medial division of the thyroarytenoideus, from internal midline of the thyroid cartilage to vocal process of the arytenoid cartilage.
Vocal ligament
Attached to the rostral border of the vocalis to attach it to the vocal process of the arytenoid cartilage.
Laryngeal muscles (4)
Cricothyroideus
Cricoarytenoideus dorsalis
Cricoarytenoideus lateralis
Thryoartenoideus
Auricular cartilage
aka pinna
One cartilage that is funnel shaped and forms the entirety of the external ear.
Tragus
Rostral boundary of the ear canal, think quadrangular plate.
Marginal cutaneous sac
aka cutaneous marginal pouch
Indentation/incisure at the lateral portion of the helix of the pinna.
Annular cartilage
Circular ring of cartilage that connects the auricular cartilage to the external acoustic meatus, helping form the ear canal.
Temporalis muscle
Attachments: Temporal fossa to coronoid process of the mandible.
Action: Close the jaw
Innervation: Mandibular branch of the trigeminal nerve (CN V)
Masseter muscle
Attachments: Zygomatic arch and masseteric fossa on the ventrolateral surface of the mandible. Fibers blend with the fibers of the temporals muscle in deep portion. Covered by a large aponeurosis.
Action: Close the jaw
Innervation: Mandibular branch of the trigeminal nerve (CN V)
Zygomatic salivary gland
Found directly ventral to the eye underneath the zygomatic arch. Gland opens into the vestibule by one main and several minor ducts lateral to the last superior molar tooth.
Medial and lateral pterygoid muscles
Hard to distinguish from one another - medial pterygoid is most of the muscle mass while lateral pterygoid is smaller.
Attachments: pterygopalatine fossa to medial surface and caudal margin of the ramus of the mandible and the angular process of the mandible. Can be felt from the medial side under the oropharynx.
Action: Close the jaw
Innervation: Mandibular branch of the trigeminal nerve (CN V)
Digastricus
Origin found under the mandibular and parotid salivary glands.
Attachments: paracondylar process of the occiptal bone to body of the mandible.
Action: Open the jaw
Rostral portion innervation: Mandibular branch of the trigeminal nerve (CN V)
Caudal portion innervation: Facial nerve (CN VII)
Rostral separated from caudal portion by a tendinous intersection that crosses the muscle belly.
Styloglossus
Attachments: Stylohyoid bone rostroventral to the palatine tonsil and inserts in the middle of the tongue.
Action: Retract and elevate the tongue.
Innervation: Hypoglossal nerve (CN XII)
Hyoglossus
Attachments: Thyrohyoid and basohyoid bones to the root of the tongue.
Action: Retract and depress the tongue.
Innervation: Hypoglossal nerve (CN XII)
Genioglossus
Attachments: Intermandibular articulation and joins its fellow on the median plane. Found on the medial side inside the tongue.
Action: Caudal fibers protrude the tongue and its rostral ones retract the apex.
Innervation: Hypoglossal nerve (CN XII)
Sternohyoideus
Attachments: Sternum and first costal cartilage to the basiohyoid bone.
Action: Draw the larynx caudally.
Innervation: Hypoglossal nerve (CN XII) and ventral branches of cervical spinal nerves.
Thyrohyoideus
Attachments: Short muscle rostral to the origin of the sternothyroideus. Thyroid cartilage of the larynx to thyrohyoid bone.
Innervation: Hypoglossal nerve (CN XII) and ventarl branches of the cervical spinal nerves.
Mylohyoideus
Attachments: Transverse fibers between the base of the mandibles from the medial surface of the body of the mandible to its fellow muscle on the midventral raphe. Inserts caudally on the basihyoid.
Action: Forms a sling that aids in the support of the tongue.
Innervation: Mandibular branch of the trigeminal nerve (CN V)
Geniohyoideus
Attachments: Lies deep to the mylohyoid. Arises at the intermandibular articulation and inserts on the basiohyoid.
Action: Draws the hyoid apparatus and larynx rostrally.
Innervation: Hypoglossal nerve (CN XII)
Name the arteries (in order) that supply the distal part of the hind limb
External iliac artery -> femoral a. -> popliteal a. -> cranial tibial -> dorsal pedal -> perforating branch of the arcuate artery.
What two main arteries supply the proximal part of the hind limb?
External Iliac artery and Internal Iliac artery
What two main arteries supply the hind paw?
Cranial tibial and saphenous arteries.
Which is larger, the perforating or arcuate artery of the hind paw?
Perforating artery.
What cranial nerves comprise the part of the lumbosacral plexus that innervates the hindlimb?
L4-S3
What nerve innervates the hamstrings?
Sciatic nerve (Hamstrings = biceps femoris, semimembranosus, semitendinosus)
What nerve innervates the external anal sphincter? What may cause this nerve to stop working and what will happen if this occurs?
Caudal rectal nerve (off of the pudendal nerve)
Perianal hernia, chronic anal sac disease or pelvic damage can cause nerve damage, and loss of this can cause loss of voluntary control of defecation.
What nerve innervates the extensors of the hock/flexors of the digits?
Tibial nerve
What does damage to the tibial nerve look like in the patient?
Sinking of the hock because it cannot be kept in extension.
What nerve innervates the flexors of the hock/extensors of the digits?
Deep peroneal/deep fibular nerve
What nerve innervates the extensors of the stifle?
Femoral nerve
What nerve innervates the adductors of the hindlimb?
Obturator nerve
Also prevents abduction
Loss is most obvious on a slippery surface.
At what vertebrae does the spinal cord end?
Around L6/L7 between the wings of the ilium, then continues as the caudal equina running through the verterbral canal.
Where do the nerves of the caudal equina exit the vertebral column?
At the vertebrae that they are named for, even if their origin is much more cranial within the spinal cord.
What is the importance of the many foramina of the skull?
Blood must get in
Nerves must come out
Which cranial nerves have parasympathetic components?
III, VII, IX, and X only
What are the names of the two types of dental nomenclature?
Anatomical shorthand system
Modified Triadan system (more common in clinics)
What is the dental formula of the adult feline?
3/3 I, 1/1 C, 3/2 P, 1/1 M
What is the dental formula of the kitten?
3/3 I , 1/1C, 3/2 P
What are the quadrants of the modified Triadan system?
Moves in a clockwise (from the vet's perspective) direction around the mouth. 1 = Upper right 2= Upper left 3= Lower left 4= Lower right
Describe how the anatomical shorthand system works to identify a specific tooth
Type of tooth is ID’d by I, C, P, or M
Number is placed on top or bottom and on either the right or left to indicate the position of the tooth.
What is the pathway of the sympathetic innervation of the head?
Approx T1 -> cervicothoracic ganglion -> middle cervical ganglion -> vagosympathetic trunk -> cranial cervical ganglion -> smooth muscle of the pupil and blood vessels, sweat, and mucosal glands of the head.
Why is the visualization of the eardrum in the dog so difficult?
Ear canal turns over 90 degrees from the external ear to the tympanic bulla. Have to point the otoscope medially.
Where is a nasogastric tube passed?
Through the common nasal meatus which is very simple rostrally and more complex/smaller caudally.
Why do we get stuffy noses with a cold?
The caudal turbinates have incredibly complex blood sinuses. An increase in blood flow from inflammation during a viral infection will cause a restriction in space = part of a stuffy nose.
Why do dogs get watery eyes with nasal swelling?
The nasolacrimal canal is very small in the dog so nasal or ocular swelling will usually occlude the canal. This will mean that tears will spill out of the eye rather than moving into the nasal cavity to evaporate.
What are the general actions the pharyngeal musculature?
Relaxation: increase the size of the lumen
Contraction: decrease the size of the lumen
Important in both swallowing and vocalization.
Where does the soft palate sit relative to the epiglottis in the living dog?
Soft palate is generally ventral to the epiglottis. (In fixed specimens they are usually contacting one another). Held in place by musculature.
What causes reverse sneezing?
In brachyocephalic dogs the soft palate is disproportionately long compared to the face. It can then become flipped over (becomes dorsal to) the larynx causing sneezing/coughing/gagging as the dog tries to fix the situation.
What must happen in order for the dog to pant?
Must dilate the pharynx to allow mouth breathing and so completely relax the pharyngeal muscles.
What types of joints form between the laryngeal cartilages and the hyoid bones?
Synovial joints
Wattles
Cheek fleshy material of the chicken. Color can be used to judge overall health (pink vs. pale or jaundiced).
Comb points
Fleshy material on the top of the head of the chicken. Color can be used to judge health like the wattles.
Pterylae
Feathered portion of bird skin
Apterylae
Non-feathered portion of bird skin (feather tracts)
What kind of keratin is found in birds/reptiles?
Beta-keratin
Patagium
The skin that stretches between the humerus and radius/ulna in the wing of the bird.
Urophygeal gland
Oil gland on the rump that helps birds with preening and waterproofing.
Are cream or brown feathers darker?
Darker feathers are stronger due to the melanins in the tissue.
What are the three elements that cause feather coloring?
Melanins, carotenoids, and porphyrins.
What are iridescent feathers an example of?
Structural colors.
Strut framework
Element of avian hollow bones that keeps them strong as the bone becomes stronger for flight.
Medullary bone
Laid down as PULLET in young female birds. Still hollow but in the larger bones as a calcium for females during egg production. Can eventually become depleted leading to soft-shelled eggs.
How many cervical vertebrae do birds have?
Variable number - swans have up to 22.
What 6 specialized reduced bones do birds have?
Keel Synsacrum Carpometacarpus Tibiotarsus Tarsometatarsus Reduced digits
What is the movement of a bird’s maxillary bone called?
Cranial kinesis
Furcula
aka the wishbone
Fused clavicles of birds
Avian pectoral muscles
For a down-stroke in flight.
Superficial to supracoracoideus.
Attachments: Keel and ventral humerus (cranial to scapula).
Avian Supracoracoideus
For an up-stroke in flight.
Deep to pectorals
Attachments: keel and dorsal humerus (caudal to scapula).
Why don’t birds fall off their perches as they sleep?
The tendons of the hock flexors are very long so as the bird kneels they tighten and flex the toes. This also helps them when carrying food after hunting.
What is the stroke pattern of avian respiration?
- To abdominal air sacs
- Through rigid lungs
- To cervical air sacs
- Out through trachea
What three holes do you find in the oral cavity?
Choana (top of the bill)
Glottis (bottom)
Esophagus
Bird mechanical papillae
Cause the food to move down the esophagus rather than back up it.
What causes the noises caused by very noisy birds?
Highly elongated trachea
What allows birds to sing dual-tone songs?
The syrinx, which allows different notes to be produced at the same times.
How does the avian heart deviate from the mammalian heart?
Much thinner R ventricle
Very pointed heart
R atrioventricular valve is muscular rather than fibrous and so can be affected by myocarditis.
What is the shell gland of the bird analogous too?
The uterus
What veins are accessible for venipuncture in the bird
R. jugular vein
Metatarsal vein
Cutaneous ulnar or Basilic vein
What organ is found in young birds and then fades in the adult?
The Bursa of Fabricius where B-lymphocytes develop. Found near the cloaca.
What accounts for the variability of normal bird stools?
Cecal droppings
Paired and very long on either side of the colon.
What organ in mammals is missing in avians?
The urinary bladder
Urates directly into the GI tract.
What is the problem with giving IM injections into the leg of a bird?
Birds have a portal renal system as well as a hepatic renal system and so drugs are often cleared before becoming systematic. This is why the pectoral muscles are generally used for IM injection in birds.
Periorbita
The cone-shaped connective tissue that encloses the eyeball and its muscles, vessels, and nerves. Continuous with the periosteum of the orbit and the face and continuous with the dura intracranially.
Lacrimal gland
Small flat gland lying deep (medial) to the orbital ligament.. Creates 2/3 of the aqueous layer of the tear film.
Levator palpebrae superioris
Narrow, superficial muscle that runs from the apex of the orbit and over the dorsal rectus and then becomes a flat tendon in the upper eyelid. Innervated by the oculomotor nerve (CN III).
How many extrinsic muscles of the eye?
7
Retractor bulbi
Two obliquus muscles (dorsal/ventral)
Four rectus muscles (dorsal/ventral/medial/lateral)
Describe the arrangement of the extrinsic muscles of the eye.
4 fascicles of the retractor bulbi in the center
Surrounded by the four rectus muscles
Obliquus muscles attach at the sclera over the ventral and dorsal rectus muscles.
What extrinsic muscles of the eye does CN III innervate?
Oculomotor: Dorsal rectus Medial rectus Ventral rectus Ventral oblique
What extrinsic muscles of the eye does CN VI innervate?
Abducens:
Retractor bulbi
lateral rectus
What extrinsic muscles of the eye does CN IV innervate?
Trochlear:
Dorsal oblique
Trochlea
Cartilagenous plaque attached at the level of the medial angle of they eye to the wall of the orbit. Holds the tendon of the dorsal oblique muscle.
Superficial gland of the third eyelid
At the bottom of the third eyelid. Produces 1/3 of the aqueous layer of the tear film. Do not confuse with the lymphatic nodules that are on the visceral side of the third eyelid.
External fibrous coat of the eye
Composed of the cornea, sclera, and limbus.
Complete
Derived from neural crest cells.
Cornea
Anterior 1/4 of the eye. Clear portion through which the iris and pupil are seen.
Sclera
Posterior 3/4 of the eye. “White” of the eye. Covered by the bulbar conjunctiva anteriorly. Attachments of the extrinsic muscles of the eye, penetration of vessels, and exit of the optic nerve posteriorly.
Limbus
The slightly thickened joining point of the sclera and the cornea.
Middle vascular coat of the eye
Aka uvea.
The iris, choroid, and ciliary body.
Incomplete.
Derived from neural crest cells.
Iris
Pigmented diaphragm surrounding the pupil. Has both circular and radial smooth muscle.
Pupil
Opening in the center of the iris.
Choroid
Posterior portion of the vascular coat firmly attached to the sclera (middle coat of the fundus). Continuous with the ciliary body anteriorly. Consists of the tapetum lucid and the nontapetal area (nontapetal nigrum).
Provides the majority of the blood flow to the globe.
Ora serrata
Junction of the choroid and the ciliary body. Usually seen as an undulating line in the retina.
Fundus of the eye
Posterior or deep portion of the eyeball that is seen with the ophthalmoscope during an eye exam.
Tapetum lucidum
Specialized layer of cells in the choroid that is multicolored and reflects light rays. Reflection causes light rays to trigger the rods and cones of the retina twice and so may be important for vision in low light.
Ciliary body
Between the iris and the choroid. Numerous muscle bundles that function in the regulation of the shape of lens.
Ciliary processes
From the ciliary body. Surround but do not attach to the lens of the eye. Consist of several hundred pigmented folds (help give the iris its color) that alternate in length and enlarge as they approach the lens. Contraction of the processes pulls on zonular fibers and makes the lens more spherical to accommodate for near vision.
Zonule
The suspensory apparatus of the lens. Composed of numerous zonular fibers.
Zonular fibers
Fine strands that pass from the ora serrata along the ciliary processes and attach to the equator of the lens. Contraction of the ciliary processes pulls on zonular fibers and makes the lens more spherical to accommodate for near vision.
Lens
Transparent and elastic roundish structure through which light passes.
Chambers of the eye
Anterior chamber: between the cornea and the iris, filled with aqueous humor.
Posterior chamber: between the iris and the lens, filled with aqueous humor.
Vitreous chamber: posterior to the lens, filled with vitreous humor.
Vitreous humor
Jelly-like proteinous substances which fills the vitreous chamber. Used often in necropsies because there may be electrolytes remaining in this, often a sterile chamber.
Aqueous humor
Continually produced by the the ciliary epithelium that covers the ciliary processes. Circulates through the posterior chamber and then into the anterior chambers. Then drained through the trabecular meshwork at the iridocorneal angle into the venous scleral sinus.
Iridocorneal angle
Angle that contains a trabecular meshwork through which the aqueous humor drains.
Scleral sinus
Venous sinus into which the aqueous humor drains.
Pectinate ligament
The meshwork in the iridocorneal angle.
Holes in the meshwork are called the spaces of Fontana.
What causes glaucoma?
Failure in the drainage of the aqueous humor of the eye, especially if the meshwork (spaces of Fontana) of the pectinate ligament becomes blocked.
Internal (nervous) coat of the eye
Retina and associated vessels and nerves.
Incomplete
Formed from a direct outgrowth of the brain.
Retina
Pars optica retinae
Pars ciliaris retinae
Pars iridica retinae
Pars optica retinae
Covers the fundus. Portion of the retina that contains the light sensitive rods and cones, the bipolar cells, and the ganglion cells. Appears as a gray-white layer that peels away from the choroid in the preserved specimen.
Pars ciliaris retinae
Non-light receptive portion of the retina over the ciliary body. Two layers thick and forms the blood-aqueous barrier through which aqueous fluid is secreted into the posterior chamber.
Pars iridica retinae
Portion of the retina over the posterior section of the iris. Double cell layer of the retina with one layer consisting of pigment cells (help give iris its color) and a second layer of myoepithelial cells.
Dilator pupillae
Myoepithelial cells of the pars iridica retinae.
Optic disk
Point at which the the optic nerves enters the posterior part of the globe. Many retinal vessels also enter here. Near or slightly inferior to the tapetum lucidum.
External jugular vein
Formed by the anastamosis of the linguofacial vein and the and the maxillary veins, with the mandibular salivary gland between the two veins.
Lingual vein
First large tributary that enters the linguofacial vein. Different radiating veins drain blood from the tongue, laryrnx, and pharynx.
Liguofacial vein
Tributary of the cephalic vein.
Has several small mandibular lymph nodes along it that are rostroventral to the mandibular salivary gland.
Facial vein
Other tributary of the liguofacial vein. Drains the dorsal surface of the muzzle
Branches: dorsal nasal
angularis oculi
Dorsal nasal vein
Branch of the facial vein that runs caudally from the nares.
Angularis oculi vein
Branch of the facial vein that runs rostrally from the medial aspect of the orbit where it is continuous with the ophthalmic plexus in the periorbita.
Deep facial vein
Another communication between the ophthalmic plexus and the facial vein. Ventral to the zygomatic bone.
Maxillary vein
Second component of the external jugular vein.
Drains the ear, orbit, palate, nasal cavity, cheek, mandible, and cranial cavity.
Facial nerve
CN VII
GSE: Innervates all of the superficial muscle of the head and face as well as the caudal belly of the digastricus and the platysma of the neck, eyelids.
SVA: Carries taste sensation from the rostral 2/3 of the tongue
GVE: parasympathetic input to the lacrimal, sublingual, and mandibular salivary glands as well as the glands of the nasal and oral cavity
Enters the petrosal part of the temporal bone through the internal acoustic meatus and them exits the eli; at the stylomastoid foramen and breaks into branches.
Major branches: auriculopalpebral, dorsal an ventral buccal branches.
Auriculopalebral nerve
Arises from the facial nerve ventral to the external acoustic meatus.
Rostral auricular branches of the auriculopalebral nerve
Braches that run through the parotid gland and are distributed to the rostral auricular muscles.
Palpebral branches of the auriculopalebral nerve
Branch that supplies the orbicular oculi (responsible for closing the eyelid).
Buccal branches of the facial nerve
Branches that run across the masseter muscle to the cheek, superior and inferior lips, and lateral surface of the nose. Ventral and dorsal branches, named in relation to the parotid duct.
Auriculotemporal nerve
Branch of the mandibular nerve (from CN V trigeminal) from between the caudal border of the masseter and external acoustic meatus.
Sensory branches to the skin of the external ear, temporal, zygomatic, and masseteric regions.
Thyroid gland
Two lobes (maybe connected by an isthmus) lateral to the first five rings of the trachea. Supplied by the caudal thyroid artery and the cranial thyroid artery.
External parathyroid gland
Small lightly colored spherical body.
Most commonly found in the fascia near the cranial pole of the thyroid gland.
Supplied by the cranial thyroid artery.
Internal parathyroid gland
Small lightly colored spherical body.
Usually within the capsule of the thyroid on the medial side of the structure.
Supplied by the cranial thyroid artery.
Cervical portion of the esophagus
From the laryngopharynx (starting at the pharyngoesophageal limen) to the thoracic inlet.
Tracheal cartilages
Approximately 35 in the dog, C-shaped, open dorsally and this opening is covered by the trachealis muscle.
Common carotid artery
Within the carotid sheath. Branches of this artery will supply all the major structures of the head.
Caudal thyroid artery
Variable origin from a major arterial vessel at the thoracic inlet. Runs cranially on the trachea to the caudal pole of the thyroid gland.
Supplies: trachea, esophagus, and thyroid gland.
Cranial thyroid artery
From common carotid artery. Runs ventrocaudally.
Supplies thyroid and parathyroid glands, pharyngeal muscles, laryngeal muscles and mucosa, cervical parts of the trachea and esophagus, and portions of the sternocephalicus and mastoid part of the cleidocephalicus.
Medial reteropharyngeal lymph node
Large lymph node near the larynx.
Drains the tonsils, tongue, nasal cavity, pharynx, salivary glands, external ear, larynx, and the esophagus.
Tracheal trunk on each side arises from this lymph node.
Internal carotid artery
Runs more cranially than the external carotid artery.
No branches off this artery but runs into the carotid canal within the tympanooccipital fissure.
Forms the cerebral arterial circle that supplies the brain.
Carotid sinus
Sac-like structure formed by the branching point of the internal and external carotid arteries. Baroreceptor. The carotid body (chemoreceptor) lies within the carotid sinus.
External carotid artery
Runs more caudally than the internal carotid artery.
Numerous branches supply other structures of the head:
Terminates by branching into the superficial temporal artery and the maxillary artery just rostrally to the auricular cartilage.
Superficial temporal artery
The smaller terminal branch of the external carotid artery.
Supplies the parotid gland, the masseter (via the masseteric artery which can be mistaken for the maxillary), the temporal muscle, the rostral auricular muscles, and the eyelids.
Maxillary artery
The larger terminal branch of the external carotid artery.
Disappears deep to the masseter muscle.
Associated with a number of cranial nerves.
Courses towards the alar canal.
Branches:
(caudal deep temporal artery, middle meningial artery, and external ophthalmic artery)
Minor palatine artery
Descending palatine artery
Terminates as the infraorbital artery.
Occipital artery
Leaves the external carotid cranially just after the internal carotid.
Supplies the muscles on the caudal aspect of the skull and the meninges.
Cranial laryngeal artery
Small ventral branch of the external carotid with a sharp curve that supplies the sternomastoideus, pharyngeal muscles, and laryngeal muscles and mucosa.
Lingual artery
Large ventral branch of the external carotid that courses rostrally to supply the tonsil and the tongue.
Closely associated with the hypoglossal nerve.
Facial artery
Large rostroventral branch of the external carotid that leaves just rostral to the lingual artery.
Supplies the lips and nose.
The sublingual artery branches off this artery.
Sublingual artery
Branch off of the facial artery that supplies the digastric muscle and the tongue.
Closely associated with the mylohyoid nerve.
Caudal auricular artery
Dorsal branch off of the external carotid artery which generally arises under the base of the ear and parotid gland.
Lateral, intermediate, and medial branches that course distally on the convex surface of the external ear.
CN V Mandibular branch
Branch of the Trigeminal nerve
Leaves the skull through the oval foramen
Branches arise over the pterygoid muscles : pterygoid, deep temporal, and masseteric nerves that contain somatic motor neurons (GSEs) to innervate the mm. of mastication.
To mylohyoid nerve, inferior alveolar nerve, lingual nerve, and auriculotemporal nerve.
Lingual nerve
Sensory
Largest and most rostral branch of the mandibular nerve
Somatosensory to the rostral 2/3 of the tongue (GSA). Does not provide any taste sensation.
Inferior alveolar nerve
Middle branches of the mandibular nerve.
Enters the mandibular foramen on the medial side of the ramus of the mandible and then runs through the mandibular canal to supply sensory nerves to the teeth.
Mental branches from the mental foramina are terminal branches of this nerve.
Runs with the inferior alveolar artery
Mylohyoid nerve
Most caudal branch of the mandibular nerve.
Both motor and sensory. Runs around the caudal aspect of the mandible to the medial side and is motor to the digastric / mylohyoid and sensory to the skin between the mandibles.
Auriculotemporal nerve
Sensory
Leavers the mandibular nerve at the oval foramen and courses caudally.
Emerges between the base of the auricular cartilage and the masseter muscle.
Supplies the ear and the lateral aspect of the head.
External ethmoidal artery
Branch of the maxillary artery (from the external ophthalmic artery that supplies the eye).
Passes and turns sharply dorsal to the extrinsic musculature of the eye, then enters an ethmoidal foramen into the cranial cavity and passes through the cribriform plate to supply the ethmoid labyrinth and nasal septum.
Descending palatine artery
Common trunk from the maxillary artery that will branch into the major palatine artery (caudal) and the sphenopalantine (cranial).
Minor palatine artery
Very small ventral branch off the maxillary artery just caudal to the descending palatine artery.
Distributed to the hard and soft palates.
Often run into during bleeds in dental work.
Major palatine artery
From the descending palatine artery - caudal branch.
Enters the caudal palatine foramen and thought the major palatine canal to supply the hard palate.
Sphenopalatine artery
From the descending palatine artery - cranial branch.
Through the sphenopalatine foramen to supply the interior of the nasal cavity.
Infraorbital artery
The continuation of the maxillary artery.
Supplies the malar a. to the eyelids, dental branches to the caudal cheek teeth, then runs through the maxillary foramen and supplies more dental branches to supply the premolars, canines, and incisors.
Terminates as the lateral and rostral dorsal nasal arteries that supply the nose and upper lip.
Inferior alveolar artery
Runs with the inferior alveolar nerve
Supplies the roots of the teeth in the lower jaw.
Branches = mental branches that supply the skin.
Olfactory nerve
CN I
SVA: sensory from the olfactory epithelium in both the nasal cavity and vomeronasal organ. In reality numerous olfactory axons passing through the olfactory foramina.
Optic nerve
CN II
SSA: from the retina to the CNS. Enters the skull via the optic canal in the presphenoid bone. Lies medial to the lateral rectus and fasicle of the retractor bulbi. Covered here by an extension of the meninges.
Oculomotor nerve
CN III
GSE: Innervation of the structures of the orbit/adnexa including the ventral, medial, and dorsal recti, the ventral oblique, and the levator palpebrae superioris muscle.
GVE Parasympathetic: innervation to the ciliary muscle and sphincter (constrictor) pupillae muscle.
Exits the skull via the orbital fissure.
Can be seen as the much smaller nerve ventrolateral to the optic nerve.
Ciliary ganglion
VERY small round expansion of the distal trunk of the oculomotor nerve. Collection of postganglionic parasympathetic cell bodies supplying the sphincter pupillae and ciliary muscles. One of the few parasympathetic ganglia that can be seen outside of the tissue innervated, and functions to regulate the size of the pupil.
Trochlear nerve
CN IV
GSE: to dorsal oblique muscle (caudal belly).
Travels through the orbital fissure.
Cannot be seen in our dissections.
Trigeminal nerve
CN V
GSA from all regions of the face, rostral part of the auricle, rostral portion of the tongue, and external acoustic meatus.
Ophthalmic, mandibular, and maxillary divisions.
Ophthalmic nerve
CN V branch
Cannot see on our specimens
Through the orbital fissure
Sensory information from the region of the forehead, the medial regions of the superior and inferior eyelids, the cornea and the rest of the globe, some of the nasal mucosa. The branches divide within the periorbita.
Branches are the frontal, nasociliary, and lacrimal nerves.
Frontal nerve
A branch off of the ophthalmic nerve that travels rostrally with the infratrochlear nerve. Innervates the medial surface of the eyelids.
Infratrochlear nerve
A branch off of the ophthalmic nerve nerve that travels rostrally with the frontal nerve. Innervates the medial surface of the eyelids.
Ethmoidal nerve
Branch of the ophthalmic nerve that passes through the ethmoidal foramen with the ethmoidal artery and through the cribriform plate to innervate the nasal muscosa and skin of the nose.
Maxillary nerve
CN V branch
Travels through the round foramen and then the rostral alar foramen, accompanied by the maxillary artery.
Sensory from the nose, upper lip, lateral regions of the eyelids, superior dental arch, some of the nasal cavity, the hard and soft palates, and the lateral region of the face over the maxilla and zygomatic bones.
Zygomatic nerve
Branch of the maxillary nerve. Enters the periorbita and divides into two branches that pass rostrally on the inner surface of the lateral part to innervate the lacrimal gland and lateral portions of the eyelids.
Pteryopalatine ganglion
Flat neuronal cluster on the dorsolateral surface of the medial pterygoid cluster next to the pteryopalatine nerve.
Collection of postganglionic parasympathetic cell bodies of CN VII whose axons travel with branches of the maxillary nerve to innervate the lacrimal glands and the mucosa of the nasal cavity and palate.
Pteryopalatine nerve
Branch of the maxillary nerve
Common nerve trunk crossing the surface of the medial pterygoid in the pteryopalatine fossa next to the pteryopalatine ganglion.
Formed by the palatine nerves and the caudal nasal nerves
Minor palatine nerve
Forms part of the pterypalatine nerve and ganglion. Innervates the palate.
Major palatine nerve
Forms part of the pterypalatine nerve and ganglion.
Innervates the palate.
Caudal nasal nerves
Forms part of the pterypalatine nerve and ganglion.
Innervates the nasal mucosa.
Infraorbital nerve
Branch of the maxillary nerve
Large rostral continuation of the nerve that passes through the maxillary foramen and the infraorbital foramen with the infraorbital artery.
Innervates the skin and adjacent structures of the superior lip and nose.
Branches into superior alveolar.
Superior alveolar nerves/branches
Branches of the infraorbital nerve that stay within the maxilla and supply the superior cheek teeth.
Abducent nerve
CN VI
GSE: lateral rectus and retractor bulbi
Emerges from the orbital fissure
Can see well on the medial side of the lateral rectus.
Vestibulocochlear nerve
CN VIII
SSA related to hearing and balance from the inner ear to the brainstem via the internal acoustic meatus
Cranial cervical ganglion
Cranial terminal point of the vagosympathetic trunk and most cranial sympathetic ganglion.
Vagus nerve and many sympathetic and motor axons innervating the pharynx branch off here. Nerves also distributed to the vessels, glands, and smooth muscles of the head.
Glossopharyngeal nerve
CN IX
Divides into pharyngeal and lingual branches
SVA - taste from the caudal 1/3 of the tongue
GVA - from caudal 1/3 of the tongue, pharynx, and carotid sinus.
GVE - parotid and zygomatic salivary glands
GSE - pharyngeal muscles
Use the external carotid artery and the cranial cervical ganglion as landmarks to ID the glossopharyngeal which is between them.
Exits via the tympanooccipital fissure and jugular foramen
Vagus nerve
CN X
GVA - abdominal and thoracic viscera
SVA - taste information from around the epiglottis
GVE - parasympathetic innervation to thoracic and abdominal viscera
GSE - skeletal muscle of the pharynx, esophagus, and larynx
Exits the skull via the tympanooccipital fissure with cranial nerves IX and XI.
Proximal ganglion of the vagus
Lies in the jugular foramen and cannot be seen in our specimen.
Distal ganglion of the vagus
Enlargement of the vagus near the split of the vagosympathetic trunk, outside the tympanooccipital fissure. Collection of visceral afferent cell bodies similar to a dorsal root ganglion adjacent to the spinal cord.
Pharyngeal plexus
The network of branches from the glossopharyngeal nerve that run to the pharynx and the tongue along with fibers from the vagus and postganglionic sympathetic axons. Also innervates the cranial esophagus.
Cranial laryngeal nerve
Found near the distal ganglion of the vagus and courses along the lateral border of the larynx. Dives between pharyngeal muscles to innervate the cricothyroid muscle and some of the laryngeal mucosa.
Accessory nerve
CN XI
GSE - sternocephalicus, brachiocephalicus, omomtransversarius, and trapezius, and also helps to contribute to the innervation of the laryngeal muscles (by joining with the vagus near the jugular foramen.
Exits via the tympanooccipital fissure and jugular foramen.
Hypoglossal nerve
CN XII
GSE - muscles of the tongue (extrinsic and intrinsic)
Exits the skull via the hypoglossal canal
Can be seen most readily near the hyoglossus but can also be found lateral to the external carotid artery.
Closely associated with the lingual artery.
Vagosympathetic trunk
Joins with the vagus at the cranial cervical ganglion. Cranial cervical ganglion gives off many axons to the walls of the pharynx.
Olfactory foramina
Holes in the cribriform plate through with fibers of the olfactory nerves pass.
Caudal laryngeal nerve
The continuation of the recurrent laryngeal nerve that runs along the trachea and dives into the caudal part of the larynx.
Supplies motor to all of the laryngeal muscle except for the cricothyroideus.
How are the cranial nerves named?
Roman numerals indicate the order in which they arise from the brain in the rostrocaudal direction.
Names are descriptive
Ciliary nerves
Branches off the ophthalmic nerve that follow the optic nerve and innervate the eyeball.
Ansa cervicalis
Loop that leaves the hypoglossal were to join the first cervical spinal nerve before rejoining the hypoglossal nerve in the region of the hyoid.
What type of renal system do avians have?
Urecotelic (can produce uric acid or urates)
Sclerotic ring
Bony ring in the avian orbit to support the more compressed eye
Pecten
Rectangular structure in the avian eye thought to provide nutrition to the eye
Columella
Only ear ossicle of the bird
Egg yolk peritonitis
Occurs if an ovum is passed from the ovary that is not caught by the infundibulum, large as it is.
Uncinate processes
Sharp processes off the avian ribs.
In what range can mammals see light? Birds?
Mammals: 400 - 700 nm
Birds: 300 - 700 nm
Adnexa
Structures around the globe both to move and support it.
Canthus (medial or lateral)
Another name for the medial/lateral commissures or angles of the eye.
What are the corresponding terms for the eye? Rostral Dorsal Caudal Ventral
Anterior
Superior
Posterior
Inferior
Equator of the eye
Circumference of the sclera cutting the globe into anterior and posterior halves. Where many extrinsic muscles of the globe attach.
What muscle opens the eyelids? What is it innervated by?
Levator palpebrae superioris
CN III
What muscle closes the eyelids? What is it innervated by?
Orbicularis oculi
CN VII
Describe the path of tear flow over the eye
1/3 of aqueous tears produced at the inferior gland of the 1/3 eyelid and 2/3 of aqueous tears produced at the superior/lateral lacrimal gland.
Tear film distributed over the eye by blinking
Move into the lacrimal puncta
Run through the lacrimal caniculi
The two caniculi meet at the lacrimal sac
Runs through the nasolacrimal duct to the ventral nasal meatus.
What is the cause of cherry eye? Treatment?
Inflammation of the lymphoid tissue of the third eyelid.
Can try to manage medically but most commonly just tack the eyelid down with suture.
How can you tell conjunctival vessels from scleral vessels?
Scleral vessels are fixed and don’t move if prodded, while conjuctival vessels do. Can be important clinically.
What does the doctor look at during an eye exam?
Mostly examines the fundus of the eye
Looks for health of the vessels in the eye
Can observe the optic disc within the fundus
What developmental structure forms the lens of the eye?
Neural crest cells that form the lens placode.
What structure forms the optic stalk and cup of the developing eye?
Outgrowths of the optic vesicle of the primordial brain. These cause the lens placode to fold and bud off into the lens.
What is a reflex?
A programmed response to a stimulus.
Includes both an afferent and efferent arm.
What does a neurological exam entail?
Assessing of different reflexes as a way of locating a structural nerve lesion.
What is the simplest type of reflex arc?
A monosynaptic reflex arc in which the afferent neuron synapses directly onto the efferent neuron. This is only possible when both afferent and efferent neurons are associated with the same structure (such as a muscle in the patellar reflex). Generally, reflexes contain more synapses than this.
Panniculus reflex
Skin twitch reflex.
Afferents and efferents processed in the spinal cord and another signal is sent for conscious perception to the brain.
What might cause an increase in the panniculus reflex?
A lesion of the cervical spinal cord.
The conscious perception of the brain is usually somewhat inhibitive of the reflex. If it is not accessed, the reflex can appear to increase.
Which of the senses are visceral?
Taste and smell
Those that cannot be tuned in and out by conscious thought.
Which of the senses are somatic?
Vision and hearing (and touch)
Those that can be tuned out by conscious thought (or that are intimately associated with musculature)
How do you test CN I?
Test sense of smell
Make sure that whatever is being used does not provide mechanical stimulation of the nasal mucosa via movement of air or irritation.
At home, owner may see decrease in appetite or change in eating behavior.
What tests can be used to assess CN II?
Pupillary light reflex Menace or startle response Obstacle course Visual tracking If vision loss is gradual, deficits most often noticed when there is a sudden change in environment.
What tests can be used to assess CN III?
Pupillary light reflex Eye movement Relative position of the pupils in both eyes in rest and during tracking Relative pupil diameter Upper eyelid position
What is mydriasis and what innervates it?
Dilation of the pupil by the dilator pupillae muscle.
Radially arranged smooth muscle around the eye
Sympathetic input from T1-T3
What is miosis and what innervates it?
Construction of the pupil by the constrictor pupillae muscle.
Circularly arranged smooth muscle around the eye like a sphincter.
Parasympathetic input from CN III
What are the responses of the pupils called when testing the pupillary light reflex?
Direct response
Consensual response in the contralateral eye.
You shine a light in the right eye and neither pupil constricts. Which nerve is lesioned?
The right optic nerve.
You shine a light in the right eye and only the right pupil constricts. Which nerve is lesioned?
The left oculomotor nerve.
You shine a light in the right eye and only the left pupil constricts? Which nerve is lesioned?
The right oculomotor nerve.
You shine a light in the right eye and both pupils constrict. Which nerve is lesioned?
There may be no lesion, or there may be a lesion of the left optic nerve if you then shine the light into the left eye and see no pupil response in either pupil. To perform the PLR you always must look in both eyes.
