Lecture 9: Surgical Anatomy of Head and Neck (Wronski) Flashcards
anesthetic injection of supraorbital n. will desensitize:
upper eyelid for optho exam (sensory)
anesthetic injection of infraorbital n. will desensitize:
rostral upper surface of face, including the upper lip to suture lacerations (sensory)
anesthetic inj. of mental n. will desensitize:
lower lip/chin to suture lacerations (sensory)
anesthetic inj. of maxillary n. will desensitize:
upper dentition for dental procedures (sensory)
anesthetic inj. of mandibuloalveolar n. will desensitize:
lower jaw/dentition for dental procedures (sensory)
anesthetic inj. of palpebral br. will desensitize:
orbicularis oculi m. for optho exam (motor)
mental n. is a cranial br. of what nerve?
mandibulo-alveolar
Where is maxillary n. blocked?
deep injection into the pterygopalatine fossa (near lateral canthus of the eye)
where is mandibuloalveolar n. blocked?
intersection of horizontal line extended caudally along occlusal surface of teeth and vertical line dropped ventrally from lateral canthus of eye
which two nerves should you block to remove both motor and sensory input to the eyelids for an optho exam? Where do you inject? **
frontal (supraorbital) and palpebral n. A single injection at the supraorbital foramen accomplishes this, because the palpebral n. travels next to the supraorbital foramen
tarsorrhaphy
Suturing the eyelids together. Performed after enucleation of the eyeball or for treatment of corneal ulcers
What nerves must be blocked for a tarsorrhaphy procedure?
supraorbital, palpebral, and zygomaticofacial. The zygomaticofacial is sensory to the lower eyelid and therefore must also be blocked
Site of nerve block for tarsorrhaphy
at the junction of the ventral rim of the orbit and the supraorbital portion of the zygomatic arch (NOT the supraorbital foramen)
What artery supplies horns in horned animals?
cornual a. (a branch of the superficial temporal). Must be ligated in dehorning
Dehorning involves blocking of which nerve? Site of injection?
cornual n. Inject ventral to temporal line b/w the lateral angle of eye and the horn. Also Inject SQ along dorsomedial border of horn in case branches of the infratrochlear n. extend into the horn
potential complication of cosmetic dehorning? How can this be avoided?
infection of frontal sinus. Results due to communication b/w exterior and the caudal frontal sinus via the cornual diverticulum. Dehorn before 6 mos. of age, because the diverticulum doesn’t invade the horn until this time
How to treat infected frontal sinus?
Perform trephination (bore circular hole into caudal or rostral sinus to drain it and introduce antibiotic solution) *avoid the frontal vein, which drains into the supraorbital foramen in the cow*
tx of infection of maxillary sinus
trephination caudodorsal to facial tuberosity to enter maxillary sinus
Do the rostral and caudal maxillary sinuses communicate?
NO
How does the frontal sinus communicate with the caudal maxillary sinus?
nasomaxillary aperture
what space lies between the dorsal and ventral concha?
middle nasal meatus
Where do the rostral and caudal maxillary sinuses drain?
through the nasomaxillary aperture into the middle nasal meatus
tears drain through the:
nasolacrimal duct
Things to avoid during trephination of rostral or caudal maxillary sinuses
dorsal buccal n.
transverse facial/deep facial veins
nasolacrimal duct
roots of 3rd and 4th cheek teeth project into which sinus in the horse?
rostral maxillary sinus
roots of 5th and 6th cheek teeth project into which sinus in the horse?
caudal maxillary sinus
Access to roots of teeth for repelling teeth can be gained in which sinuses?
maxillary and frontal sinuses. Teeth are driven from the sinus into the oral cavity for extraction
How to repell the 6th cheek tooth?
It is difficult to expose the root through the caudal maxillary sinus, so perform trephination of sinus flap of frontal sinus through the frontal maxillary opening
what is the guttural pouch?
bilateral mucous sacs that are ventral diverticulae of the auditory tubes situated at the base of the cranium and atlanto-occipital joint
how can respiratory infection travel to guttural pouch?
mucous memb. of guttural pouch is continuous with that of the nasopharynx at the auditory tube
Signs of infected guttural pouch *
- epistaxis (nose bleed)
- swelling at caudal angle of mandible
- empyema (collection of pus)
- chondroid bodies (solidified pus)
- dysfunction of cranial nerves 3,7,9,10,11,12)
how to drain infection of guttural pouch
insert catheter through ventral nasal meatus –> auditory tube –> guttural pouch
epistaxis from infected guttural pouch is usually from which vessels?
internal carotid and maxillary vein?
common sign of cranial n. dysfunction secondary to infection of guttural pouch
dysphagia due to trauma to pharyngeal branches of vagus n.
which lymph nodes lie immediately ventral to guttural pouch?
medial retropharyngeal lymph nodes
laryngeal hemiplegia (roaring) *
Trauma to recurrent laryngeal n. results in paralysis of cricoarytenoideus dorsalis m., which abducts the vocal folds. Leads to partial occlusion of laryngeal cavity as the vocal folds project too far medially into the air current during inspiration
what side does roaring most often occur on?
left side (90% of the time!)
Where do the cranial laryngeal n. and a. enter the larynx?
between the cricoarytenoideus lateralis and dorsalis mm.
ventriculoectomy
surgical correction of laryngeal hemiplegia (roaring). Involves eversion and excision of the laryngeal saccule which results in formation of granulation tissue between the vestibular and vocal folds that hopefully pushes the vocal fold laterally.
What is a tie back?
sx correction of laryngeal hemiplegia in which suture is placed through the muscular process of the arytenoid cartilage and anchored at the caudal portion of the median ridge of the cricoid cart., which simulates the fx of the atrophied cricoarytenoideus dorsalis m.
the opening of the laryngeal saccule is known as
lateral ventricle
