H&N1 6.pdf

11/09/2024...

11/09/2024 Head and ILOs neck 1 Describe the functions and clinical relevance of the muscles of mastication in the canine and equine Discuss the path of the trigeminal nerve and it's relevance to canine dental work Describe the blood supply to and from the head, including vessels of clinical concern Describe the blood supply of the dental arcades and nasal cavity Describe the locations of the lymph nodes and salivary glands of the head and neck and discuss in a clinical context Identify structures of the head with respect to aural surgery Describe important species differences in soft tissues of the head © School of Anatomy, University of Bristol. Not for distribution. 1 2 https://www.studyblue.com/notes/note/n/mmm/deck/3998269 Starting superficially: muscles of Superficial and facial expression deep ‘face’, skull Several conditions can affect the Orbicularis Platysma muscles of facial expression and oculi mastication Regional Anaesthesia, dentistry Nerve paths important for localizing damage Injuries http://veterinarymedicine.dvm360.com/ Euthanasia of farm animal https://www.vetstream.com/equis/Content/Disease/dis00132 species Dehorning/disbudding Buccinator Sinus infections © School of Anatomy, University of Bristol. Not for distribution.. 3 4 Kaminski et al. 2017 Human attention affects facial expressions in domestic dogs Scientific Reports volume 7, Article number: 12914 Facial nerve CNVII – motor innervation Muscles of Facial Expression Muscles of the ear (also some innervation from elsewhere) Muscles of the eyelids Muscles of the nose, cheeks and lips Passes through skull at In Guru magazine (science lifestyle magazine), issue 3, page 27, stylomastoid 2011: issuu.com/GuruMag/docs/guru03/27 in a story "Face the truth - the art of seeing someones true feelings“ https://www.flickr.com/photos/sme rikal/5877123410 Photo by:smerikal. foramen CONFIDENTIAL AND NOT FOR DISTRIBUTION, © School of Anatomy, University of Bristol. Not for distribution. COPYRIGHT OF UNIVERSITY OF BRISTOL. 5 6 1  11/09/2024 Facial nerve Auriculopalpebral branch Muscles of the eyelids, ear & forehead © School of Anatomy, University of Bristol. Not for distribution. damage results in drooping of the ear, narrowing of the palpebral fissure and an inability to close the eye Dorsal & Ventral buccal branches Muscles of the lips and cheeks Damage to results in paralysis of the lip Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. and cheek muscles allowing spillage of food during mastication and may also lead to deformation of the muzzle Also: Caudal auricular & colli branches ALSO CAUDAL BELLY OF DIGASTRICUS CONFIDENTIAL AND NOT FOR DISTRIBUTION, Image from: http://veterinaryimagebank.com/index.php/image/show/98 by PieroG58 COPYRIGHT OF UNIVERSITY OF BRISTOL. 7 8 https://www.vetstream.com/equis/Content/Disease/dis00132 Facial muscles of the horse TECA Surgery http://www.wm-referrals.com/wp- content/uploads/2012/11/TECA-early-in-the-post- operative-period1.jpg Levator of the upper lip Total Ear Canal Ablation Treatment to resolve chronic changes to the (from: Smeak DD. Surgery of the ear canal and pinna. Saunders Manual of Small Animal Practice, 3rd ed., Birchard and Sherding editors, Elsevier, 2006) ear canal from otitis Ability to flare nostrils interna and media Important for keeping food Principle structures at in the mouth – ‘quidding’ risk: Facial nerve Depressor of Care with fitting headcollars Retroauricular vein the lower lip and bridles – nerve damage Parotidoauricularis muscle © School of Anatomy, University of Bristol. Not for distribution.. Parotid salivary gland from poor fit/trauma https://www.willows.uk.net/specialist-services/pet-health- information/soft-tissue/teca 9 10 Lymph nodes in Parotid Retropharyngeal white Going slightly deeper: Muscles of Note proximity to parotid and mastication mandibular salivary glands ‘Trigeminal muscles’ Temporalis Masseter Pterygoids Digastricus (also facial n) Mandibular (submandibular) Prescapular (Superficial cervical) © School of Anatomy, University of Bristol. Not for Distribution. Facial Trigeminal 11 12 2  11/09/2024 Trigeminal nerve (CNV) Muscles of Mastication Temporalis © School of Anatomy, University of Bristol. Not for distribution.. Much deeper dissection into the pterygopalatine fossa (zygomatic arch © School of Anatomy, University of Bristol. Not for distribution.. removed) V1 ophthalmic division, sensory from skin between eyes & forehead Masseter Digastricus V2 maxillary division, sensory from skin over muzzle and upper teeth V3 mandibular division, sensory from skin over mandible and cheek, lower teeth AND motor to muscles of mastication 13 14 Foramina of CNVII & CNV Oval foramen (mandibular branch of Muscles of Mastication Orbital fissure (opthalmic trigeminal nerve, CNV3) branch of trigeminal nerve, CNV1) Stylomastoid foramen (facial nerve CNVII) Infraorbital foramen Round foramen via (maxillary branch of rostral alar canal trigeminal nerve, CNV2) (maxillary branch of trigeminal nerve, CNV2) © School of Anatomy, University of Bristol. Not for distribution.. Image from Textbook of Veterinary Anatomy. Dyce, Sack & Wensing. 3rd Ed. 15 16 The horse Masticatory Muscle Conditions Masticatory muscle myositis (MMM) – common idiopathic autoimmune inflammatory myopathy in dogs Tetanus (trismus, lockjaw, muscle spasm) reduced opening of jaws – due to spasm of masticatory muscles Trigeminal nerve myopathies can be caused by T inflammation, neoplasia or trauma M Ophthalmic branch: corneal anaesthesia, loss of sensation to upper eyelid and eye medial P canthus. P Maxillary branch: loss of sensation to eye lateral canthus, lower eyelid, face including nostril and palate, upper teeth Mandibular branch: loss sensation to jaw line and lower teeth, unilateral or bilateral paralysis The jaw is moved laterally in chewing by of masticatory muscles → inability to close © School of Anatomy, University of Bristol. Not for distribution.. action of ipsilateral masseter and mouth, difficulty eating and drinking, https://www.studyblue.com/notes/note/n/mmm/deck/3998269 contralateral pterygoids. Most common is idiopathic mandibular paralysis 17 18 3  11/09/2024 Regional nerve blocks - dentistry Regional nerve blocks http://veterinarynews.dvm360.com/ loudoun.nvcc.edu http://veterinarydentistry.net/ Caudal maxillary block (infraorbital nerve V2) Rostral maxillary block (Infraorbital nerve V2) http://veterinarymedicine.dvm360.com/ veterinarymedicine.dvm360.com http://veterinarymedicine.dvm360.com/ http://veterinarymedicine.dvm360.com/ Note: Brachycephalics (eg., cat) short canal Upper canine removal (includes Rostral mandibular block (inferior alveolar Caudal mandibular block (inferior gives both rostral and caudal maxillary block! alveolar bone) nerve V3) via mental foramen alveolar nerve V3) 19 20 Blood and lymph in the H&N – bridging superficial and deep Head is highly vascularised! Oxygenated blood to face and brain Deoxygenated blood for processing Clinical considerations include Infection- Guttural Pouch Mycosis (ICA) Auricular & palate surgery Pulse points Arterial and Venous blood sampling 21 22 Arterial supply to the brain Contributions from: 1. Vertebral Arteries 2. Ventral Spinal Artery 3. Internal Carotid Artery (in most mammals) The Vertebral and Ventral http://www.onlineveterinaryanatomy.net/sites/default/files/original_media/image/asset_8349_Basilar%20Artery.jpg spinal aa. join to form the Basilar artery, which contributes to the Cerebral Arterial Circle (Circle of Willis) ICA also contributes (in most mammals) 23 24 4  11/09/2024 Primary branches of the external carotid artery Cranial laryngeal Ascending pharyngeal Occipital Caudal auricular Superficial temporal LINGUAL FACIAL MAXILLARY 25 26 Arterial blood supply to the head Supply to the face, nose and mouth Lingual: the tongue, palatine tonsil Facial: Lips, lateral nose, angle of the mouth Superficial temporal: eyelids, dorsum of nose, masseter CAC Maxillary: Cr. External ophthalmic: the orbit ICA Laryngeal Occ. Inferior alveolar: lower alveoli & teeth, lower lip and chin CCA ECA AP Infraorbital: upper alveoli & teeth Superf. Temp. Lingual Ethmoidal: nasal cavity Transverse Facial facial Maxillary Major & Minor Palatine: hard and soft palates C. Auric. 27 28 Equine linguofacial trunk Note pulse point Equine guttural pouch Both ECA and ICA pass through the walls, mycosis can lead to damage 29 30 5  11/09/2024 Venous drainage of the head Venous drainage of the head – for interest 2 2’: External and internal jugular Veins are mostly satellite, where 4: Linguofacial they are they are named as the 8: Maxillary vein (and artery) artery 9 9’: Auricular veins Notable variations from this 10: Retroarticular (retrocondylar) include External Jugular Vein (~CCA) & Linguofacial Vein vein joining to maxillary 11: Superficial temporal Veins generally drain from deep to 12: Pharyngeal plexus superficial 13: Facial 14: Lingual Note the venous plexus (Pterygoid, 15: Pterygoid plexus (deep) Opthalmic & Pharyngeal) 16: Ophthalmic plexus (deep) These drain some more 17: Deep facial superficial vv. (e.g. angularis 18: Angularis oculi oculi) and can cause infections from around the eye to track to deeper structures 31 32 Venepuncture https://vetstudentinthetropics.wordpr ess.com/tag/sheep/ © School of Anatomy, University of Bristol. Not for distribution. oslovet.norecopa.no 33 34 © School of Anatomy, University of Bristol. Not for distribution. © School of Anatomy, University of Bristol. Not for distribution. Notice the two veins draining from the facial superficially to deep in the head Linguofacial V. Note: Sinuses (swellings) on deep facial, buccal and transverse facial veins Major veins are superficial Can take arterial blood samples from lingual, facial, CCA and venous sample from Muscular pump - non-functional valves transverse facial vein sinus 35 36 6  11/09/2024 Jugular furrow Rhomboideus Trapezius Jugular vein sits between Splenius brachiocephalicus and Nuchal ligament sternocephalicus in a groove or furrow Species variations: Note that the tongue drains to both lingual vein and maxillary vein. Brachiocephalicus Sternocephalicus 37 38 Lymph Nodes of the Head Lymph nodes of the head and neck 3 lymphocentres: Parotid receives from dorsal structures (skin, bones, orbit and some mm of mastication) Part of a system with nodes and vessels, act as a filter for antigens Mandibular (submandibular nodes palpable in canine) and release competent T and B cells receives from muzzle, salivary glands, tongue, intermandibular space, mm of mastication Part of a general clinical exam Retropharyngeal Indicator of regional problems receives from deep structures (pharynx, larynx and other nodes) E.g. infection or neoplasia Caseous lymphadenitis in ruminants Lymph Nodes of the Neck Strangles in equine (can affect guttural Prescapular centre (Superficial cervical) (palpable in canine) pouch) Cranial to shoulder joint, drains superficial neck, upper trunk & Indicator of systemic problems proximal forelimb E.g. neoplasia, spread of infection http://www.lbah.com/word/tips/weekly-health-exam/ Deep cervical centre chain of nodes in neck Important in disease surveillance (disease cranial, middle, caudal groups along length of trachea staging, monitoring spread) & meat safety drain deep and ventral neck structures 39 40 Parotid Retropharyngeal Drain via the tracheal ducts Note proximity Lymphatic vessels, one each side of trachea in neck to parotid and mandibular Arise in retropharyngeal lymph node salivary glands End in lymphatic duct (on R) or thoracic duct (on L) (or may drain into external jugulars at thoracic inlet) Parotid Retropharyngeal Thoracic duct Cisterna Chyli Mandibular Lumbar Tracheal duct Deep Iliac cervical Deep inguinal Mediastinal Bronchial Superficial Mandibular inguinal (submandibular) Mesenteric Popliteal Position of diaphragm Prescapular (Superficial cervical) © School of Anatomy, University of Bristol. Not for Distribution. 41 42 7  11/09/2024 ILOs Describe the functions and clinical relevance of the muscles of mastication in the canine and equine Discuss the path of the trigeminal nerve and it's relevance to canine dental work Describe the blood supply to and from the head, including vessels of clinical concern Describe the blood supply of the dental arcades and nasal cavity Describe the locations of the lymph nodes and salivary glands of the head and neck and discuss in a clinical context Identify structures of the head with respect to aural surgery Describe important species differences in soft tissues of the head 43 8