Vessels and Nerves of the Head

External jugular v.

Formed by confluence of the linguofacial v. and maxillary v.

Caudal to mandibular salivary gland

Linguofacial v.

Lingual and facial v. join

Lingual v.

The first large tributary that enters the linguofacial v.

Drains the tongue, larynx, and part of the pharynx

Facial v.

Enters the linguofacial v.

The dorsal nasal v., angularis oculi v., and deep facial v. communicate with it

Dorsal nasal v.

From facial v.

Runs caudally from the nares

Angularis oculi v.

From facial v.

Passes rostrally from the medial aspect of the orbit

Communicates with ophthalmic plexus

Deep facial v.

Deep to zygomatic bone

Communicates facial v. with ophthalmic plexus

Maxillary v.

Drains the ear, orbit, palate, nasal cavity, cheek, mandible, and cranial cavity

Transverse facial v. and sinus

In horse

Located immediately ventral to facial crest

Connects facial and superficial temporal veins

Accessible for venipuncture

Deep facial v. and sinus

In horse

Located just ventral to the transverse facial v.

Joins the facial v.

Buccal v. and sinus

In horse

Ventral to the transverse facial and deep facial vv.

Connects facial v. and superficial temporal v.

Supraorbital v.

In horse

Emerges from the supraorbital foramen with the a. and n.

Frontal v.

In bovid

Located dorsomedial to the orbit

Courses rostrally and drains into angularis oculi v.

Supraorbital v.

In bovid

Connects with frontal v.

Exits supraorbital foramen

Facial nerve (CN7)

Innervates the superficial muscles of the head that deal with facial expression

Also innervates the caudal belly of the digastricus m. and platysma of the neck

Leaves skull at stylomastoid foramen, where it divides into several branches

Auriculopalpebral n.

Arises as facial n. curves rostral to the external acoustic meatus

Rostral auricular branches

From auriculopalpebral n.

Courses through the parotid gland and distributed to rostral auricular mm.

Palpebral branches

From auriculopalpebral n.

Continues toward the orbit to innervate orbicularis oculi m.

Buccal branches of facial n.

Course across masseter m.

Innervate muscles of the cheek, superior and inferior lips, and lateral surface of the nose

Dorsal and ventral to parotid duct (in the carnivore)

Common carotid a.

Gives off cranial and caudal thyroid aa. and internal and external carotid aa.

Caudal thyroid a.

Passes cranially on trachea and supplies trachea, esophagus, and thyroid gland

Cranial thyroid a.

Ventral surface of carotid at pharynx

Supplies thyroid and parathyroid glands and pharyngeal mm.

Also supplies the laryngeal mm. and mucosa, cervical parts of trachea and esophagus, sternocephalicus m., and mastoid part of cleidocephalicus m.

Internal carotid a.

Enlargement near the origin is the carotid sinus

Enters carotid canal at tympano-occipital fissure

Emerges and loops at foramen lacerum

Penetrates the dura and supplies the brain

External carotid a.

Passes cranially medial to digastricus m.

Gives off numerous branches

Occipital a.

Comes from external carotid a.

Passes dorsally to supply the muscles on the caudal aspect of the skull and meninges

Cranial laryngeal a.

From external carotid a.

Ventral branch supplies sternomastoideus m., pharyngeal mm., and laryngeal mm.

Lingual a.

From external carotid a.

Ventral branch and passes rostrally to supply tonsil and tongue

Hypoglossal n. runs parallel to this a.

Facial a.

From external carotid a.

Leaves medial to digastricus m., courses rostrolaterally between digastricus m. and masseter m., lateral to mandible to supply lips and nose

The sublingual a. is a branch that is accompanied by the mylohyoid n.

Runs rostrally to the tongue

Caudal auricular a.

From external carotid a.

Arises at base of ear

Courses dorsally under caudal auricular mm.

Superficial temporal a.

Termination of the external carotid

Supplies the parotid gland, masseter m., temporal mm., rostral auricular mm., and eyelids

Maxillary a.

The larger terminal branch of the external carotid a.

Deep and closely associated with numerous cranial nn.

Numerous branches

Inferior alveolar a.

From maxillary a.

Enters mandibular foramen, supplies branches to roots of teeth in the lower jaw

Mental a. supplies the skin

Caudal deep temporal a.

From maxillary a.

Arises near inferior alveolar a. and enters the temporal m.

External ophthalmic a.

Arises from maxillary a. when it emerges from the alar canal

Penetrates the periorbita and supplies structures within

Minor palatine a.

From maxillary a.

Passes ventrally and caudally to the hard palate

Supplies soft and hard palate

Major palatine a.

From maxillary a.

Enters caudal palatine foramen and through the major palatine canal to supply hard palate

Sphenopalatine a.

From maxillary a.

Passes through the sphenopalatine foramen to the interior of the nasal cavity

Infraorbital a.

Maxillary a. termination

Supplies the malar a. to the eyelids and the dental branches to the caudal cheek teeth

Enters maxillary foramen and passes through the infraorbital canal

Emerges from the infraorbital canal and terminates as lateral and rostral dorsal nasal aa.

Supply the nose and superior lip

Occipital a., linguofacial trunk, masseteric a., superficial temporal a.

What does the external carotid a. give off in the equid?

Linguofacial trunk

In equid

From external carotid a.

Gives off lingual a. and facial a.

Inferior labial a., superior labial a., sublingual a., lateral nasal a., dorsal nasal a., angularis oculi a.

Which arteries come off from the facial artery in the equid?

Masseteric a.

In equid

From masseteric a.

Courses into caudal aspect of the masseter m.

Superficial temporal a.

In equid

Gives rise to transverse facial a.

• Used for a pulse; palpable

Maxillary a.

In equid

Main continuation of the external carotid

Has numerous branches (inferior alveolar a., external ophthalmic a., infraorbital a.)

Inferior alveolar a.

In equid

Courses through the mandibular foramen and gives rise to mental a., which courses through the mental foramen

External ophthalmic a.

In equid

Supplies many branches to the eye and surrounding area

Gives rise to supraorbital a., which exits the supraorbital foramen

Infraorbital a.

In equid

Enters maxillary foramen to the infraorbital canal; supplies upper incisors and maxillary teeth

Exits infraorbital foramen to supply the lateral side of the face

Ruminant

In which species is there no internal carotid a.?

Linguofacial trunk

In ruminant

From external carotid a.

Lingual and facial aa.

Superior and inferior labial aa.

What does the facial a. give off in the ruminant?

Facial a.

In ruminant

From linguofacial trunk

Can be used for a pulse as it crosses the mandible

Goats

In which species is there no facial a.?

Superficial temporal a.

In ruminant

Courses dorsally caudal to the orbit

Gives rise to the transverse facial a.

Gives rise to the cornual a., which supplies blood to the base of the horn

Cornual a.

In ruminant

Comes from superficial temporal a.

Supplies base of horn

Inferior alveolar a., malar a., infraorbital a.

What does the maxillary a. supply in the ruminant?

Inferior alveolar a.

In ruminant

From maxillary a.

Gives rise to the mental a. through the mental for

Malar a.

In ruminant

From maxillary a.

In the goat, it can give rise to angularis oculi a., lateral caudal nasal a., and dorsal nasal a. (comes from facial in bovids the majority of the time)

Mandibular n. (from CN5)

Leaves the cranial cavity through the oval foramen

Branches arise on pterygoid m. ventral and lateral to the apex of the periorbita

Buccal n.

From mandibular n.

Enters cheek lateral to zygomatic gland

Sensory to mucosa and skin of the cheek

Lingual n.

From mandibular n.

Largest and most rostral of branches of mandibular n.

Passes between the styloglossus and mylohyoideus m.

Sensory to rostral 2/3rd of tongue

Inferior alveolar n.

From mandibular n.

Enters mandibular foramen on medial side of mandible

Courses through the mandibular canal, sensory nn. to teeth

Mental nn. that come through mental foramen are branches and innervate the lower lip

Mylohyoid n.

From mandibular n.

Motor and sensory

Caudal branch of inferior alveolar

Supplies branch to the rostral belly of digastricus m. and continues to mylohyoid m.

Auriculotemporal n. (sensory)

From mandibular n.

Leaves at oval foramen and emerges between the base of the auricular cartilage and masseter m.

Supplies skin of the external ear and the temporal, zygomatic, and masseteric regions

Cornual n.

Branch of the trigeminal n.

Supplies sensory to the horn

Parallel to the temporal line

Dehorning

Cornual branches of the infratrochlear n.

In small ruminant

Sensory

Branch of ophthalmic off the trigeminal n.

More medially to cornual n. and runs caudomedially to horn

Dehorning

Supraorbital n.

In equid

Courses through supraorbital foramen

From trigeminal n.

Sensory fibers from the skin of the forehead and upper eyelid

Anesthetize for surgical procedures or ophthalmic exam

Olfactory n. (CN1)

Sense of smell

Will find on brain

Optic n. (CN2)

Also called prechiasmatic optic tract

Will find with eye dissection

Conveys special sense of vision

Oculomotor n. (CN3)

Enters periorbita

Controls eye movement by innervating dorsal, medial, and ventral recti muscles

Innervates ventral oblique and palpebrae superioris

Ciliary ganglion is enlargement at termination

Trochlear n. (CN4)

Eye movement by dorsal oblique m.

Will dissect with eye

Trigeminal n. (CN5)

3 main branches; convey sense of touch, pain, and temp.

Mandibular n.

Ophthalmic n.: Passes through orbital fissure and supplies sensory n. that enters periorbita

Maxillary n.: Emerges from rostral alar foramen

Zygomatic n., pterygopalatine n., infraorbital n.

Branches of maxillary n.

Zygomatic n.

Branch of maxillary n.

Enters periorbita and innervates lacrimal gland and lateral portion of superior and inferior eyelids

Pterygopalatine n.

Branch of maxillary n.

Arises beyond the pterygopalatine ganglion on the ventral surface of the maxillary n.

Divides into three nerves: major and minor palatine nerves and the caudal nasal n.

Infraorbital n.

Branch of maxillary n.

Continuation of maxillary n. in the pterygopalatine fossa

Enters infraorbital canal and gives off superior alveolar branches

Abducent n. (CN6)

Controls eye movement by innervating lateral rectus and retractor bulbi mm.

Will dissect with eye mm.

Facial n. (CN7)

Supplies motor innervation to muscles of facial expression

Regulates tear and saliva production

Vestibulocochlear n. (CN8)

Sense of hearing and balance

Will see on the brain

Glossopharyngeal n. (CN9)

Innervates pharyngeal mm. and mucosa

Sense of taste to caudal 1/3 of tongue

Helps regulate saliva production

Vagus n. (CN10)

Supplies structures from head to caudal abdomen

Proximal ganglion

Distal ganglion of the Vagus

Pharyngeal plexus

Proximal ganglion

Part of vagus n.

Lies at jugular foramen; cannot be seen

Distal ganglion of the Vagus

Part of vagus n.

Caudal to the cranial cervical ganglion (sympathetic)

Caudal to the distal ganglion, the nerve becomes the vagosympathetic trunk

Pharyngeal plexus

Part of vagus n.

Innervates caudal pharyngeal mm. and cranial esophagus

Cranial laryngeal n.

Branch of vagus n.

Leaves vagus n. at distal ganglion

Supplies cricothyroid m. and laryngeal mucosa

Caudal laryngeal n.

Branch of vagus n.

Innervates all other muscles of the larynx

Terminal segment of recurrent laryngeal n.

Accessory n. (CN11)

Controls movement of the head and shoulder

Hypoglossal n. (CN12)

Controls movement of the tongue

Passes through the hypoglossal canal

Closely associated with lingual a.