TMJ, Face, Skull

TMJ Mandibular fossa of temporal bone with condyle of mandible Incongruent surfaces Two joint cavities with articular disc interposed Lower cavity = hinge joint Upper joint = gliding

TMJ

TMJ

Mandible

Mandible

TMJ Capsule Surrounds the joint Encloses the disc Attaches above the margins of the mandibular fossa To the neck of the mandible Inner aspect of capsule attaches to disc Above disc – capsule loose Below disc - taut

TMJ Capsule

TMJ Capsule

TMJ Ligaments Lateral ligament - AKA TMJ ligament Sphenomandibular From zygomatic bone to run inferiorly and posteriorly to blend with the joint capsule to attach to lateral and posterior parts of the neck of the mandible Sphenomandibular Strong thin flat band lying on medial aspect of the joint Passes inferiorly and forwards from the spine of the sphenoid to the lingula Stylomandibular Extends from the apex of the styloid process to the lower part of the posterior border of the ramus of the mandible, near the angle

TMJ Capsule

TMJ Innervated by CN V, Mandibular branch Movements Elevation, depression, retraction, protraction, side to side Elevation and depression involves the hinge like rotation of the condyle against the disc in the lower compartment Protraction and retraction – actions whereby the condyle and disc move as one unit against the mandibular fossa. In protraction the condyle and disc glide forwards so that the condyle rides on the articular eminence – retraction = opposite

CN V Trigeminal

TMJ Motions

TMJ Motions

TMJ Side to side – grinding movements Mandible is alternately protracted and retracted with the two sides moving in opposite directions so that one side is protracted while the other is retracted Actions combined with elevation and depression, rhythmically and alternately

Muscles of Mastication Masseter Temporalis Lateral pterygoid Medial pterygoid All innervated by CNV Opening of jaw (depression) primarily passive or gravity assist

Masseter

Temporalis

Pterygoids

Pterygoids

Pterygoids

Nerve Supply to Face Sensory by three divisions of CN V – opthalmic, maxillary, mandibular Innervation of muscles of facial carried out by CN VII – the Facial Nerve Origin, branches, motor functions, sensory functions, parasympatheric functions

CN V

CN V

Sensory to Face

Sensory

Scalp Three Layers This allows scalp to move over the skull Outer = skin Beneath that – subcutaneous layer with many nerves and vessels running through here, binds skin to inner layer Galea Aponeurotica – AKA epicranial aponeurosis Galea attaches to pericranium via loose CT This allows scalp to move over the skull Most muscles of face attach to skin, this arrangement allows them to be more mobile.

Scalp

Scalp

CN VII – The Facial Nerve Motor nerve to muscles of facial expression with one notable exception Origin = lower pons Branches – common nerve enters face Temporal Zygomatic Buccal Mandibular Cervical

Motor to Face CNVII

CN VII Motor Functions Sensory functions Parasympathetic Muscles of facial expression External ear Sensory functions Ant. 2/3 of tongue Soft palate Pharynx Parasympathetic Gland stimulation

CN VII

Muscles of Facial Expression Primary action is to act as either a sphincter or dilator of the orifices of the face Facial expression is a by-product Orifices Lips = labia Nose = nares; Nostrils, Septum, Ala, Apex, Root Eyelids = palpebrae External Ear = auricle, lobule = soft portion

Selected Muscles of Facial Expression * = learn Orbicularis Oculi Levator Palpebrae Superioris* O: Root of Orbital Cavity I: Skin of upper eyelid A: Raises upper eyelid N: Note Well, Nerve = CN III Ptosis is a condition of denervation to this muscle causing drooping of the eyelid, a clinical symptom indicating more loss

Facial MM

Facial MM

Facial MM

Facial MM

Muscles Continued Occipitofrontalis Corrugator Auricular muscles of the ear – ant., post., sup. Nose Nasalis Procerus Depressor Septi

Facial MM

Facial MM

Ear MM

Nose MM

Nose MM

Muscles Mouth Depressor anguli oris Depressor labii inferior Mentalis Risorius Orbicularis oris Buccinator* Zygomaticus major Zygomaticus minor Levator labii superioris Platysma

Platysma

Mouth

Facial MM

Extra Occular Muscles of the Eye Muscles that move the eyeball Innervated by: CN III (most), CN IV (1),CN VI (1) Many have an origin from the annulus tendinous, a common tendon ring attached around the optic canal Most attach to the sclera of the eyeball

Eye MM

Muscles * Superior Rectus – rotates eyeball upward and medially –CN III Medial Rectus – rotates medially (ADD) – CN III Lateral Rectus – rotates eyeball laterally (ABD) – CN VI Inferior Rectus – rotates eyeball downward and medially – CN III

Eye MM

Eye MM

Eye MM

Eye MM

Muscles * Superior Oblique – rotates eyeball downward and lateral – CN IV Inferior Oblique – rotates eyeball upward and lateral – CN III Combined motions Up and medial = sup.rectus Up and lateral = inferior oblique Straight up = sup. rectus and inf. oblique Straight down = inf. rectus and sup. oblique Down and medial = inferior rectus Down and lateral = superior oblique Lateral Gaze = ABD of one eye with ADD of the other

Eye Movements

Eye Movments

Eye Movements