muscles of the head and neck. tmj mandibular fossa of temporal bone with condyle of mandible ...
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Muscles of the head and neck
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
– 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– 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– 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