Ch. 6 Articulation

Introduction to Articulation

• Definition of Articulation: The process of joining two elements (e.g., bones).

• Articulatory System: Comprises mobile and immobile structures in the oral cavity that come together to produce sounds (phonemes).

• Phonemes: The smallest unit of sound in speech; achieved through correct positioning of articulators.

Source Filter Theory

• Function of Vocal Folds: Produce a quasi-periodic tone, characterized by inconsistencies in periodicity.

• Vocal Tract: Sound produced by vocal folds travels through the oral cavity, pharyngeal cavity, and nasal cavity.

• Sound Interpretation: Sound is shaped into different phonemes (vowels/consonants) based on turbulence created by the position of articulators.

• Volume and Frequency Relationship: As volume increases, frequency decreases; vice versa.

  • Example: Good posture and head voice increase vocal tract size, affecting sound production.

Vowel Production

• Changing Shapes of Vocal Tract: Resonant frequencies govern the production of vowels; differing tongue positions yield different vowels (e.g., high vs low vowels).

• Articulators: Include both mobile (e.g., tongue, mandible) and immobile structures (e.g., alveolar ridge, hard palate).

Mobile and Immobile Articulators

• Mobile Articulators (9): Tongue, mandible, soft palate (velum), lips, cheeks, fauces, pharynx, larynx, hyoid bone.

• Immobile Articulators (3): Alveolar ridge, hard palate, teeth.

Importance of Articulator Positioning

• Impact on Speech: Distance between mobile and immobile articulators affects intelligibility; closer articulation results in clearer sound production.

Anatomy of the Face and Cranial Skeleton

• Facial Skeleton: Comprises 28 bones in three groups: facial bones, cranial bones, middle ear bones (6).

• Mandible: Unpaired bone with body and ramus; contains key landmarks such as the mental foramen and alveolar processes.

• Temporomandibular Joint (TMJ): A hinge and gliding joint allowing multi-directional movement crucial for speech and chewing.

• Functions (9): chewing, sucking, phonation, facial expression, breathing, posture, pressure of middle ear

Maxilla and Other Facial Bones

• Maxilla: Paired, Largest facial bone; consists of 4 processes (zygomatic, frontal, palatine, alveolar) & 6 landmarks (infraorbital foramen, infraorbital margin, nasal crest, nasal notch, canine eminence, & maxillary sinus).

• Nasal Bones: Paired, smaller bones articulate with the frontal bones superiorly, and the maxillae laterally; they form the bridge of the nose and contribute to the shape and support of the nasal cavity.

• Palatine Bones: Paired, form part of the hard palate and contribute to the nasal cavity's structure.

• Vomer: Small unpaired bone forming part of the nasal septum.

• Nasal Conchae: Contribute to the shape of the nasal cavity, with three types (superior, middle, inferior).

Additional Facial Bones

• Zygomatic Bone: Paired, makes up the cheekbone; has multiple processes connecting to other facial bones. Frontal process articulates with the frontal bone, the temporal process articulates with the temporal bone, & the maxillary process articulates with the maxillary bone. The zygomatic arch is on the temporal process of the zygomatic bone.

• Lacrimal Bone: Smallest bones forming part of the eye orbit.

Hyoid Bone and its Functions

• Overview: Suspends the larynx; connects the phonatory and articulatory structures, assisting in speech production.

Cleft Lip and Palate

• Developmental Issues: Occur due to genetic and environmental factors during early development (6-8 weeks); can be unilateral or bilateral. Unilateral can be on either side, (incomplete start below the nose), (complete go up to the nose). Bilateral

• Feeding Impact: Cleft lip causes fewer issues than cleft palate; affects the ability to feed effectively.

• Surgical Repairs: Typically take place within the first year for lips and 12-18 months for palates, often requiring multiple surgeries.

Speech Implications for Cleft Conditions

• Delays in Speech Development: Often associated with surgeries and adjustments due to anatomical challenges.

• Pressure Consonant Production: Particularly challenging; higher pressure consonants become difficult due to the lack of adequate closure in the oral cavity.

Cranial Skeleton Details

• Main Sutures: Include squamous, lambdoid, coronal, and sagittal sutures connecting various cranial bones.

• Ethmoid Bone: Contributes to cranial, nasal and orbital spaces; key landmarks include crista galli (protecting brain) and cribiform plate (cranial nerve 2 passes through optic nerve), orbital contributes to inner eye.

• Sphenoid Bone: Butterfly-shaped bone with multiple articulations and pathways for cranial nerves.

• Frontal Bone: Forms the forehead and upper eye orbit, connecting with zygomatic and nasal bones.

• Parietal and Occipital Bones: Cover respective lobes of the brain.

• Temporal Bone: Paired, has four major portions (squamous, tympanic, mastoid, and petrous), contributing to various structures related to hearing and mastication.

Dentition

• Dental Status: Describes teeth situation; "edentulous" refers to lacking teeth, often seen in older adults. “Adentulous” refers to no teeth

• Dental Arch Components: Discusses anatomy and layers of a tooth (root, crown, enamel, etc.).

• Types of Teeth: Includes incisors, cuspids, canines, premolars, molars, and wisdom teeth.

• Deciduous teeth: Also known as baby teeth, these are the first set of teeth that typically emerge in childhood, usually starting around six months of age.

• Succesional teeth: Adult teeth

Dental Occlusion

• Classifications: Bite. Include class one (typical/normal), class two (overbite), class three (underbite).

• Importance in Oral Motor Exams: Observations during exams should note any misalignment or dental issues affecting speech production.

• Misaligned Teeth:

Vocal Tract Cavities

• Oral Cavity: Primary site for speech production, comprising the tongue and mandible.

• Buccal Cavity & Nasal Cavity: Functions in swallowing and sound production; aids in warming and humidifying air.

• Pharyngeal Cavity: Bifurcation into nasal and oral pharynx; crucial for swallowing and voice modulation.

Muscles of Articulation

• Facial Muscles: Integral for forming facial expressions; include (Orbicularis oris muscles • Risorius muscle • Buccinator muscle • Levator labii superioris muscles • Zygomatic minor muscles • Levator labii superioris alaeque nasi muscles • Levator anguli oris muscle • Zygomatic major muscle • Depressor labii inferioris muscle • Depressor anguli oris muscle • Mentalis muscle • Platysma muscle)

• Tongue Musculature: Divided into oral and pharyngeal components; intrinsic muscles shape the tongue while extrinsic muscles position it for sound production.

• 7 lingual landmarks: median sulcus, terminal sulcus, foramen secum, lingual tonsil, sublingual folds, lingual frenulum, & circumvallate papillae.

• Intrinsic Muscles (4): Superior longitudinal, inferior longitudinal, transverse, and vertical muscles; these muscles work together to allow for precise movements of the tongue, facilitating articulation and speech production.

• Extrinsic Muscles (5): Genioglossus, Hyoglossus, Styloglossus, Palatoglossus, and the Chondroglossus; these muscles play a crucial role in positioning the tongue within the oral cavity, enabling a wide range of sounds during speech.

• Mandibular Elevators & Depressors: Masseter muscle • Temporalis muscle • Medial pterygoid muscle • Lateral pterygoid muscle • Digastricus muscle • Mylohyoid muscle • Geniohyoid muscle • Platysma muscle

• Muscles of the Velum: Levator veli palatini muscle • Musculus uvulae muscle • Tensor veli palatini muscle • Palatoglossus muscle • Palatopharyngeus muscle

• Mastication Muscles: Important for chewing, including the masseter and temporalis.

• Velopharyngeal Muscles: Key for closing off the nasal cavity during speech; dysfunction can lead to hypernasality.

• Pharyngeal Muscles: Facilitate swallowing and impact speech, particularly during singing. Superior pharyngeal, (inferior pharyngeal cricopharyngeus and thyropharyngeus muscles), and middle pharyngeal constrictor, Salpingopharyngeus muscle, Stylopharyngeus muscle.