BMS MSK Lecture 4 Fall 2023 Student PDF

BMS Anatomy Lecture 4 Face & Scalp, Muscles of Mastication, TMJ, Neck Vasculature and Intro to Cranial Nerves Presented By: (Toronto Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Dr. M. Doroudi; mdoroudi...

BMS Anatomy Lecture 4 Face & Scalp, Muscles of Mastication, TMJ, Neck Vasculature and Intro to Cranial Nerves Presented By: (Toronto Campus) Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Dr. M. Doroudi; [email protected] Head Chapter; Pages: 861 – 869, 783 – 876 Boucher Campus) Neck Chapter; Page: 1020 Dr. K. Lumsden; [email protected] Scalp Skin – physical barrier from trauma and potential pathogens Dense CT – hair follicles, vessels, nerves and lymph Aponeurosis – aka the “ galea aponeurotica” continuous with muscle Loose CT – mobility of the scalp Pericranium – dense irregular CT, tightly adhered to cranium bone Muscles of Scalp, Forehead, and Eyebrows Origin: Galea aponeurotica layer of skull Insertion: 1.Frontalis: skin over the eyebrows 2.Occipitalis: Superior nuchal line Action Muscles of Orbit (Eye Socket) Orbicularis Oculi a sphincter muscle arranged in concentric bands around the upper and lower eyelids. The main function of the orbicularis oculi muscle is to close the eyelids. This occurs when the muscle contracts. Levator palpebrae superioris is a triangular-shaped muscle located in each upper eyelid. The primary function is elevation and retraction of the upper eyelid. Muscles of Nose and Ears Ø Muscles of the nose Ø Provide evidence of breathing behaviors Ø Relatively unimportant in humans Ø Muscles of the ears Ø In animals helps to direct the ears toward the sources of sounds Muscles of Mouth, Lips, and Cheeks v Elevators, retractors, and evertors of the upper lip v Levator labii superioris v Zygomaticus major and minor v Risoris Muscles of Mouth, Lips, and Cheeks v The orbicularis oris, the sphincter around the mouth = Closes and protrudes lips (as in kissing), and helps keep food in the mouth v The buccinator ( L., trumpeter) in the cheek = Presses cheeks against teeth and lips, as in whistling; helps to keep food in the mouth, and resists distension of the mouth Muscles of Mouth, Lips, and Cheeks vDepressors, retractors, and evertors of the lower lip Ø Several dilator muscles radiate from the lips and angles of the mouth, somewhat like the spokes of a wheel, retracting the various borders of the oral fissure collectively, in groups, or individually. Note: In this slide ONLY review the name of the muscles in the face, so as an ND practitioner, if you hear the name of face muscles, your will not be surprised that why you did not hear from us!! Note: In this slide, pay attention to the facial expressions that made by those muscles used in the clinic to test the CN VII, i.e. raising the eyebrows, closing the eyes, and pursing the lips. Muscles of Mastication Muscle Origin Insertion Innervation Temporalis Temporal fossa and fascia - Coronoid process - Anterior border of ramus of mandible Mandibular nerve (V3) Masseter Zygomatic arch Lateral surface of ramus of mandible Mandibular nerve (V3) Function Muscles of Mastication Muscle Origin Insertion Innervation Medial pterygoid Mainly: pterygoid process of sphenoid bone Medial surface of angle of mandible Mandibular nerve (V3) Lateral pterygoid Mainly: pterygoid process of sphenoid bone Articular disc and to the neck of the mandible Mandibular nerve (V3) Function Temporo-Mandibular Joint Articular Surfaces – Disc – Articular Tubercle – Mandibular Fossa – Mandibular Condyles Temperomandibular joint (TMJ) Combined hinge and planar type of synovial joint Mandibular fossa Articular tubercle Condylar process Mandible Articular surfaces include: 1. Condylar process of mandible 2. Articular tubercle of temporal bone 3. Mandibular fossa of temporal bone TMJ-articular disc (meniscus) Superior synovial cavity Articular disc Condylar process Inferior synovial cavity Fibrocartilaginous disc that separates the joint cavity into superior and inferior compartments each with its own synovial membrane The superior and inferior compartments are separate both structurally and functionally TMJ-articular capsule Temporal bone Articular capsule Mandible Articular capsule: loose covering around the circumference of the joint It attaches to the margins of articular area on temporal bone and around the mandible and it is lined by synovial membrane TMJ-lateral ligament Temporal bone Articular capsule Lateral ligament Mandible It consists of two short bands on the lateral surface of the articular capsule It extends inferiorly and posteriorly from inferior border and tubercle of the zygomatic process of the temporal bone to the lateral and posterior aspect of the neck of the mandible The lateral ligament is covered by the parotid gland and strengthens the TMJ laterally, and helps prevent posterior dislocation of the mandible TMJ-Sphenomandibular ligament Supporting, extrinsic ligament It extends from the spine of the sphenoid to the medial surface of the ramus of the mandible It does not contribute significantly to the strength of the TMJ LATERAL VIEW MEDIAL VIEW Spine of sphenoid Sphenomandibular ligament Ramus of mandible TMJ-stylomandibular ligament Supporting, extrinsic ligament It extends from the styloid process of the temporal bone to the inferior and posterior borders of ramus of mandible This ligament separates the parotid gland from the submandibular gland and limits movement of the mandible at the TMJ LATERAL VIEW MEDIAL VIEW Styloid process Styloid process Sphenomandibular ligament Stylomandibular ligament Angle of mandible Stylomandibular ligament Angle of mandible Movements of TMJ The basic movement involved in opening of the mouth is the anterior movement of the head of the mandible and the articular disc on the articular surface of the mandibular fossa When the mouth is full opened the head of the mandible lies inferior to the articular tubercle Dislocation of TMJ Dislocation can occur in the TMJ during yawning or taking a large bite when the mandible dislocates anterior to the articular tubercle A sideways blow to the chin when the mouth is opne can dislocate the TMJ on the side that received the blow Temporomandibular Joint (TMJ) Nerves of Face and Scalp Aorta Ascending aorta Arch of aorta Brachiocephalic artery (head and neck) L Common carotid artery (brain) L Subclavian artery (upper limb) Descending Aorta (rest of body) Subclavian artery branches Pre-scalane Part 1. Vertebral artery --> brain supply 2. Internal thoracic artery --> anterior thoracic wall and breast tissue 3. Thyrocervical trunk --> larynx, trachea, esophagus thyroid Post-scalene Part 1. Dorsal scapular artery *Changes name to Axillary artery as it passes under the clavicle – enters the upper limb Carotid Artery Branches The left and right common carotid arteries supply the head and neck with oxygenated blood; The common carotid divides (bifurcates) at the level of C3 or C4 cervical vertebrae to form the external and internal carotid arteries. External supplies blood to the face and neck Internal supplies brain, eyes Carotid Artery Branches = External Carotid Artery Branches = External Carotid Artery Branches = Internal Venous Drainage of the Head and Neck The venous drainage of the head and neck begins from three main venous systems: 1.Intracranial: Cerebral veins (sinuses) 2.Superficial veins 3.Deep veins These sources form the two main veins of the neck — the internal and external jugular veins. These veins drain all of the blood from the head and neck and are somewhat comparable to the internal and external carotid arteries. Venous Drainage of the Head and Neck External Veins of Face PERIPHERAL NERVES 31 pairs of spinal nerves Serve the upper limb, trunk and lower limb 12 pairs of cranial nerves Serve the head and neck Autonomic nerves All of these are the routes by which all signals travel FROM the brain and spinal cord to the body structures such as muscles, skin and organs Sensory signals can be conscious or unconscious Motor signals can be conscious or unconscious Cranial Nerves: 36 Note: In this session, we ONLY need to learn the number and name of the cranial nerves. The rest of this table will be taught later.