Articulation



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  • Articulation

  • Articulation-

  • Articulators-

    • the structures which allow these adjustments

  • This mechanism consists of a supportive framework and a muscular system.



  • Articulation-Supportive Framework

  • Supportive framework is mostly made up by facial skeleton, the lower jaw or mandible, and the cervical vertebrae.

  • Articulation-The skull

  • The skull can be divided into the cranium and the facial skeleton.

  • Cranium-

    • Braincase

    • Houses and protects the brain

  • Facial Skeleton-

    • forms framework for organs of mastication, production of speech, respiration, special senses, and muscles used in facial expression

  • Facial Skeleton

  • The facial skeleton includes 14 bones:

    • Mandible (1)

    • Maxillae (2)

    • Nasal bones (2)

    • Palatine bones (2)

    • Lacrimal bones (2)

    • Zygomatic bones (2)

    • Inferior conchae (2)

    • Vomer (1)



  • Bones of the Facial Skeleton





  • Temporomandibular Joint (TMJ)

  • The mandible articulates with the temporal bone by means of a joint that permits both hingelike movement and gliding action.



  • Maxillae

  • Paired set of bones that form entire upper jaw

  • Each bone consists of:

    • Body

    • Zygomatic process

    • Frontal process

    • Alveolar process

    • Palatine process

  • Maxilla



  • Nasal Bones

  • 2 small oblong plates of bone

  • Form the bridge of the nose



  • Palatine Bones

  • Two ‘L’ shaped bones.

  • Horizontal plates contribute to floor of nasal cavity and roof of mouth.

  • Anterior portion articulates with palatine process of maxilla.

  • Lateral portion turns and the bone extends upwards.



  • Palatine Bones



  • Lacrimal Bones

  • Smallest facial bones.

  • Form medial wall of the orbital cavity.

  • Zygomatic Bones

  • Important muscles of articulation and mastication are attached on this bone.

  • Vomer Bone

  • Unpaired thin quadrilateral plate

  • Interior half of the bony nasal septum

  • Cavities of the Vocal Tract

  • Size and shape of the vocal tract during phonation result in changes in resonance.

  • The vocal tract is divided into 5 cavities:

    • Buccal

    • Oral

    • Pharnygeal

    • Paired nasal (2)

  • Buccal Cavity

  • Space limited by the lips and cheeks externally and the gums and teeth internally.

  • Communicates with the oral cavity through small spaces between the teeth and where the ‘wisdom teeth’ should be.

  • Oral Cavity

  • Bounded by:

    • Anteriorly and laterally- teeth and alveolar process

    • Superiorly- hard and soft palate

    • Posteriorly- palatoglossal arch

    • Inferiorly- muscular floor or the tongue

  • Oropharyngeal Isthmus

  • How the oral cavity and the pharyngeal and nasal cavities communicate.



  • Bounded by:

    • Laterally- palatoglossal arch

    • Superiorly- soft palate

    • Inferiorly- dorsum or back of the tongue



  • Pharyngeal Cavity

  • Musculomembranous tube running from the base of the skull to the 6th cervical vertebra.

  • 12 cm in length.

  • Continues down into the esophagus.

  • Divided into 3 areas:

    • Nasopharynx

    • Oropharynx

    • larygopharynx



  • Nasopharynx

  • Bounded superiorly by the rostrum (‘beak’) of the sphenoid to the soft palate inferiorly.

  • The Eustachian tube opening is in this area

  • Oropharynx

  • Starts at the level of the soft palate and continues to the level of the hyoid bone.

  • Laryngopharynx

  • Bounded superiorly at the level of the hyoid and is continuous with the esophagus inferiorly. (clip)

  • Nasal Cavities

  • Made up of 2 symmetrical chambers separated by the nasal septum.

  • Nasal septum-medially placed, vertically directed plate of bone and cartilage



  • Articulators

  • Lips

  • Teeth

  • Tongue

  • Mandible

  • Hard Palate

  • Soft Palate



  • Functions of the Mouth:

  • There are both biological and nonbiological functions.

    • Biological

      • Communicates between the digestive and respiratory tracts and the exterior.

      • Initiation of the digestive process.

    • Nonbiological

      • Modify the resonant characteristics of the vocal tract and may also generate speech sounds.

  • Muscles of the Face and Mouth

  • Lips are the most mobile part of the face due to the many facial muscles that act on them.

  • Many of the muscles insert directly into the skin.

  • The muscles of the lips and face are so intrinsically related, they exhibit functional unity.

  • Teeth

  • Both biological and nonbiological functions

    • Biological: precursors of the digestive process

    • Nonbiological: add to structure of face, normal speech production.

  • Humans have two sets of teeth during life:

    • Deciduous: developed in utero, appear in infancy and early childhood, smaller and whiter than permanent teeth.

    • Permanent: appear at early age and last through out life unless disease intervenes

  • Occlusion

  • The relationship of the upper and lower jaw.

  • Class I Occlusion

    • Normal profile

    • Cusps of the first mandibular molar are ½ tooth length ahead of the maxillary molar.



  • The Tongue

  • Has function in taste, mastication, and deglutition.

  • The most important and active of the articulators.

  • Modifies the shape of the oral cavity.

  • Can be divided into:

    • Tip: nearest front teeth

    • Blade: below the alveolar ridge

    • Front: below the hard palate

    • Back: beneath the soft palate

    • The Mandible

  • Main function is mastication but is used to modify the vocal tract in speech.

  • The jaws never fully close during speech.

  • Primary movements of the jaws are elevation and depression.

  • It may also be protruded and retracted.

  • The Palate

  • Roof of the mouth, separating the oral and nasal cavities.

  • Modifies the degree of coupling between the nasopharynx and the remainder of the vocal tract.

  • Consists of a bony plate in front and a muscular valve behind. It is usually described as having 3 parts:

    • Alveolar arch

    • Hard palate

    • Soft palate

  • The Hard Palate

  • The relatively hard, bony anterior portion of the palate

  • It forms a partition between the nasal passages and the mouth.

  • This partition is continued deeper into the mouth by a fleshy extension called the soft palate.



  • Function

  • The interaction between the tongue and the hard palate is essential in the formation of certain speech sounds, example /t/, /d/.

  • The Hard Palate

  • Formed by the medial projections of the palatine processes of the maxilla.

  • Posterior ¼ is formed by the palatine bones.

  • Covered by a mucous membrane which is highly developed at the alveolar arch to form wrinkles called rugae.

  • Palatal arch-height of the hard palate, variable across individuals. Has direct bearing on the acoustic properties of the oral cavity and may contribute to voice characteristics.

  • The Soft Palate

  • The soft palate (or velum) is the soft tissue constituting the back of the roof of the mouth.

  • The soft palate is movable, consisting of muscle fibers sheathed in mucous membrane.

  • The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone.

  • The Soft Palate

  • Function:

  • It is responsible for closing off the nasal passages during the act of swallowing, and also for closing off the airway.

  • During sneezing, it protects the nasal passage by diverting a portion of the excreted substance to the mouth.

  • The Soft Palate (Velum)

  • The soft palate also retracts and elevates during speech to separate the oral cavity (mouth) from the nasal cavity in order to produce the oral speech sounds. If this separation is incomplete, air escapes through the nose, causing speech to be perceived as overly nasal.

  • The uvula, hanging from the end of the soft palate, is responsible for the sound of snoring. Touching the uvula or the end of the soft palate evokes a strong gag reflex in most people.



  • Cleft



  • In the birth defect called cleft palate, the left and right portions of this plate are not joined, forming a gap between the mouth and nasal passage (a related defect affecting the face is cleft lip).

  • Cleft palate has a severe impact upon the ability to nurse and speak but is now cured through reconstructive surgical procedures at an early age.






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