Head and Neck 2 PDF

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11/09/2024 ILOs Head and Neck 2 Describe the paths of the facial and trigeminal nerves, with respect to skull features Describe the joints and ligaments of the skull, including the TMJ Discuss the location, drainage, function and clinical relevance of sinuses in the skull Describe the innervation of the horn with reference to horn disbudding or removal Describe important species differences in skull anatomy 1 2 Clinical relevance The bones of the skull Lacrimal Frontal Injuries Regional anaesthesia Occipital Dentistry Euthanasia of farm animal species Parietal Nasal Dehorning/disbudding www.whvc.co.uk Sinus infections Incisive Temporal Maxilla Palatine Zygomatic http://vetdentalcenter.com/veterinarians/services/oral-surgery/ http://www.farmingmagazine.com/livestock/handling-horns/ http://www.nadis.org.uk/bulletins/disbudding-calves.aspx Lateral view 3 4 The bones of the skull The mandible Coronoid process Occipital Sphenoid Ramus Pterygoid Condylar process CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY Palatine Angular process OF BRISTOL. OF BRISTOL. Nasal Dorsal view Ventral view Image from http://www.real3danatomy.com/bones/dog-mandibles-3d.html 5 6 1  11/09/2024 The brachycephalic skull The horse skull CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY CONFIDENTIAL AND NOT FOR DISTRIBUTION, OF BRISTOL. COPYRIGHT OF UNIVERSITY OF BRISTOL. https ://www.dovepress.com/strategies-for-the-management-and-prevention-of-conformation- rel a ted-r-peer-reviewed-fulltext-article-VMRR Nasoincisive notch Facial Crest 7 8 The horse skull The horse skull CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY OF BRISTOL. OF BRISTOL. 9 10 Hyoid Apparatus – a reminder! Frontal bone CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY OF BRISTOL. Bovine & porcine CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY OF BRISTOL. http://www.onlineveterinaryanatomy.net/content/hyoid-apparatus-dog 11 12 2  11/09/2024 Temporomandibular Joint (TMJ) Joints of the skull Mandibular Symphysis Cartilagenous (Scondary © School of Anatomy, University of Bristol. Not for distribution. cartilaginous, contains fibrocartilage) Fractures common in ‘high-rise’ falls, RTAs and dog fights Care when doing dentals http://vetdentalcenter.com/veterinarians/services/oral-surgery/ www.mypetsdentist.com 13 http://www.onlineveterinaryanatomy.net/content/articulation-atlas-and-axis- 14 Atlas and Axis Sinuses Diverticula of the nasal cavity that excavate the skull bones Largely after birth & alters conformation of the head Do retain connection with nasal cavity but generally openings are small All species have frontal and maxillary sinuses Equine frontal sinus drains into the caudal maxillary Image by Sebastia Giralt (Creative Commons) from www.psypost.org/2014/02/feeling- sinus and then through powerless-increases-the-weight-of-the-world-literally-22739#prettyPhoto nasomaxillary opening occipital-bone-dog All other species the frontal Atlantooccipital joint- ‘yes’ joint sinus drains into the back of flexion/extension the nasal cavity via Atlantoaxial joint- ‘no’ joint ethmoidal meatuses Dogs have a maxillary recess Allows rotation Image from http://www.onlineveterinaryanatomy.net/content/right-side-canine-cranium-medial-view 15 16 Frontal Sinuses Note close relationship between roots of cheek teeth and maxillary sinus. Apical abscesses can invade sinus, and sinus infections can invade tooth root 17 18 3  11/09/2024 Sinus infection Horns (Cattle) Horn is permanent bone covered by horn Grows continuously (whereas antlers are maxillary sinus shed each year) infection (Youtube) Invaded by frontal sinus early in life (~6 mths) www.whvc.co.uk Innervation via cornual nerve (branch of the trigeminal, CNV2) jaz-myvetlife.tumblr.com www.thegaitpost.com 19 20 Dehorning Disbudding Horn Innervation Must be performed by a Horns are easier to veterinary surgeon prevent than remove Should not be a routine Usually done using hot procedure irons Risks of injury to vet and Local anaesthesia still other people involved required Risks to cow Bleeding Infection http://www.nadis.org.uk/bulletins/disbudding-calves.aspx 21 22 Local Anaesthesia Horns (Sheep/Goats) Block the cornual nerve (branch of V2) Horn cross section determines shape LA deposited sub-cutaneously Goat, oval grow straight dorsally Midway between lateral canthus of the eye & base of horn along Sheep, triangular, curl temporal ridge For larger horns also infiltrate LA along caudal aspect of the horn Clinical: Can grow into head - pressure necrosis to desensitise sub-cut branches of 2nd cervical nerve Innervation more complex – dehorning/disbudding of goats done under general anaesthesia by a vet http://www.nadis.org.uk/bulletins/disbudding-calves.aspx http://www.farmingmagazine.com/livestock/handling-horns/ www.nadis.org.uk www.nadis.org.uk In Practice 2012;34:518-522 doi:10.1136/inp.e6301 23 24 4  11/09/2024 Considerations for pre- Foramina and Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. slaughter stunning fossae of the skull and key In the pig the extent of the frontal sinuses mean that it cranial nerves is a poor candidate for captive-bolt stunning. By Uwe Gille (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons © School of Anatomy, University of Bristol. Not for distribution. 25 26 Facial nerve (CNVII) Fossae, foramina and cranial nerves Fossae (singular fossa) are the ‘ditches’ in which things can sit Foramina (singular foramen) are the holes through which structures pass These structures are usually nerves, arteries and veins Many of the nerves passing through the skull in foramina are ‘cranial nerves’. These are a class of nerve which do not go through the spinal cord but instead innervate structures of the head and neck via direct contact with the brain. You have already met cranial nerve X – the vagus nerve Processes, tubercles are things that stick out, and other structures may attach to them eg muscles. © School of Anatomy, University of Bristol. Not for distribution. Relatively superficial dissection You will do more on cranial nerves in the neuro block! Motor to the muscles of facial expression, taste from rostral 2/3 of tongue Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. 27 28 Trigeminal nerve (CNV) Foramina of CNVII & CNV Oval foramen Opthalmic, maxillary and mandibular branches (mandibular branch of Orbital fissure (opthalmic trigeminal nerve, CNV3) branch of trigeminal nerve, CNV1) © School of Anatomy, University of Bristol. Not for distribution. Much deeper dissection into the pterygopalatine fossa (zygomatic arch removed) Stylomastoid foramen (facial nerve CNVII) Sensory innervation from most of face and head Infraorbital foramen Round foramen via rostral alar canal Three branches total – V1&V2 entirely sensory, V3 sensory AND (maxillary branch of (maxillary branch of trigeminal nerve, CNV2) motor to muscles of mastication trigeminal nerve, CNV2) Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. 29 30 5  11/09/2024 Foramina of CNVII & CNV Oval foramen Foramina of CNVII & CNV (mandibular branch of Mandibular foramen trigeminal nerve, CNV3) (mandibular branch of trigeminal nerve, CNV3) Mental foramen (mandibular branch of trigeminal nerve, CNV3) Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. 31 32 ILOs Describe the paths of the facial and trigeminal nerves, with respect to skull features Describe the joints and ligaments of the skull, including the TMJ Discuss the location, drainage, function and clinical relevance of sinuses in the skull Describe the innervation of the horn with reference to horn disbudding or removal Describe important species differences in skull anatomy 33 6