A&P chapter 10 Flashcards - Easy Notecards

An Anterior View

An Anterior View of the Human Skull with Major Cranial and Facial ones
The labeled bones include the frontal, parietal, temporal, sphenoid, ethmoid, nasal,
lacrimal, zygomatic, maxilla, and mandible. Each bone is color-coded to distinguish its
anatomical position and structure. (Source: LadyofHats, Public domain, via Wikimedia
Commons)

Anatomy of Articulation and Resonance

Anatomy of Articulation and Resonance
The respiratory and phonatory systems generate the source energy of speech production
for verbal communication. Then it is shaped into speech sounds. The three subsystems of
speech production are respiration, phonation, and articulation/resonance. They work in a
coordinated fashion to make verbal communication functional. The complicated
synchronization of these subsystems produces speech sounds sequentially to produce
meaningful utterances With oral phonemes, the air escapes from the oral cavity, and with nasal phonemes, it
escapes from the nasal cavity. We open and close the velopharyngeal port to use nasal
or oral tract, respectively.

The smallest sound unit that makes meaning is called "phoneme." In English, there are 44
basic phonemes, and the strings of these form our verbal communication. An example of a
phoneme is /p/. Phonemes are language-specific, which means that different languages
have their own sets of phonemes.
The voice generated at the level of vocal folds travels through the upside-down L-shaped
cavity formed by the pharynx and oral or nasal cavity. These passages from the vocal folds
to the point that air escapes are called vocal tracts, and we have two of them. The two
vocal tracts are the oral tract and nasal tract. We use one of the two vocal tracts to produce
oral or nasal phonemes.

Illustration of Oral and Nasal Tracts with Airflow Direction During
Speech The top panels depict the anatomical pathways of the oral tract (left) and nasal
tract (right). The bottom panels show airflow patterns. Speech sounds produced through
either pathway are shaped by resonance characteristics and reflect specific places and
manners of articulation.

Velopharyngeal Port Movements During Speech

Velopharyngeal Port Movements During Speech This diagram illustrates
the position of the velopharyngeal port during speech production. When the port is
closed (blue), air is directed through the oral tract to produce oral sounds. When the port
is open (red), air flows into the nasal cavity, enabling the production of nasal sounds.
Based on the different configuration of the oral tract and nasal tract, the speech sounds from
each tract presents with a unique speech sound. The three nasal phonemes in General
American English (GAE) are /m/ as in the word “me,”/n/ as in the word “no,” and /ŋ/ as in the
word “sing.” Oral phonemes (e.g., /z/) resonate in the oral cavity. Nasal phonemes resonate
in both the oral and nasal tracts. For example, with a nasal phoneme /n/, the sound
resonates in the oral cavity to the alveolar ridge, and the air flows out through the nasal
cavity. Students in Speech-Language Pathology learn the International Phonetic Alphabet
(IPA), classification of the phonemes, and other details about segmental and
suprasegmental aspects of verbal communication in the Phonetics course.
Articulation is the contact, approximation, or separation of speech organs for speech
production. There are fixed articulators and movable articulators. Fixed articulators do not
move independently, such as teeth and hard palate. Movable articulators move freely, such
as lips, tongue, jaws, and soft palate. Next, we will study the structures related to
articulation/resonance.

The Mouth and Surrounding Structures
The cheeks, tongue, and palate frame the mouth, which is also called the oral cavity (or
buccal cavity). The structures of the mouth are illustrated in At the entrance to the mouth are the lips, or labia (or labium if talking about one lip). Their
outer covering is skin, which transitions to a mucous membrane in the mouth. Lips are very
vascular with a thin layer of keratin; hence, they are "red." They have a substantial
representation on the cerebral cortex. The lips cover the orbicularis oris muscle, which
surrounds the mouth and regulates what comes in and goes out of the mouth.

labial frenulum

The labial frenulum is a midline fold of mucous membrane that attaches the inner surface
of each lip to the gum. The cheeks make up the oral cavity’s sidewalls. While their outer
covering is skin, their inner covering is mucous membrane. This membrane consists of non-
keratinized, stratified squamous epithelium, featuring layers of cells that secrete mucus or
saliva to serve as a protective barrier between the oral cavity and internal organs. The
function of stratified squamous epithelium is to protect structures against abrasion. Between
the skin and mucous membranes are connective tissue and buccinator (the cheek) muscles.
The next time you eat some food, notice how the buccinator muscles in your cheeks and the
orbicularis oris muscle around your lips contract, helping you keep the food from falling out
of your mouth. Additionally, notice how these muscles work when you are speaking.

Muscles of Facial Expression Many of the muscles of facial expression
insert into the skin surrounding the eyelids, nose and mouth, producing facial
expressions by moving the skin rather than bones.

orbicularis oris

The orbicularis oris is a circular muscle that moves the lips. The orbicularis oculi is a
circular muscle that closes the eye. The occipitofrontalis muscle moves up the scalp and
eyebrows. The muscle has a frontal belly and an occipital (near the occipital bone on the
posterior part of the skull) belly. In other words, there is a muscle on the forehead (frontalis)
and one on the back of the head (occipitalis), but there is no muscle across the top of the
head. Instead, the two bellies are connected by a broad tendon called epicranial
aponeurosis, or galea aponeurosis (galea = “apple”) (Figure 10.4, p. 268). The physicians
originally studying human anatomy thought the skull looked like an apple.

A large portion of the face is composed of the buccinator muscle, which compresses the
cheek. This muscle allows you to whistle, blow, and suck; and it contributes to the action of
chewing. There are several small facial muscles, one of which is the corrugator supercilii,
which is the prime mover of the eyebrows. Place your finger on your eyebrows at the point
of the bridge of the nose. Raise your eyebrows as if you were surprised and lower your
eyebrows as if you were frowning. With these movements, you can feel the action of the
corrugator supercilii. Additional muscles of facial expression are presented in

Knowledge about the muscles in facial expression is essential for SLPs. Facial expression
impacts communication greatly and transmits various non-linguistic information. Also,
damages to certain muscles for facial expression could impact the articulator and resonator
movements. For example, facial paralysis, secondly to the nerve damages that affect the
lower part of the face may cause difficulties in closing the lips completely. Individuals in such
situations could experience difficulty in producing bilabial stop consonants.
We learned about Peripheral Nervous System (PNS) in Module 4. Many of you remember
that Cranial Nerve (CN) VII, facial nerve, innervates many muscles of facial expressions
(Module 4, p. 136). Also, Cranial Nerve (CN) V, trigeminal nerve innervates muscles of the
lower jaw (Table 10.2, p. 273). Dysfunctions of these muscles could be presented as the
loss of intentional muscular activities (paralysis) or muscle weakness (paresis). As with the
somatic regions, either paralysis or paresis of these muscles of facial areas could be
secondary to the deficits of the lower motor neurons or those of the upper motor neurons.

The pocket-like part of the mouth that is framed on the inside by the gums and teeth, and
the outside by the cheeks and lips is called the oral vestibule. Moving farther into the mouth,
the opening between the oral cavity and throat (oropharynx) is called the fauces (like the
kitchen "faucet"). The main open area of the mouth, or oral cavity proper, runs from the
gums and teeth to the fauces.
When you are chewing, you do not find it difficult to breathe simultaneously. The next time
you have food in your mouth, notice how the arched shape of the roof of your mouth allows
you to handle both digestion and respiration at the same time. This arch is called the palate.
The anterior region of the palate serves as a wall (or septum) between the oral and nasal
cavities. This region is a rigid shelf against which the tongue can push food. It is created by
the maxillary and palatine bones of the skull and, given its bony structure, is known as the
hard palate. If you run your tongue along the roof of your mouth, you will notice that the hard
palate ends in the posterior oral cavity, and the tissue becomes fleshier as you feel the end
of the hard structure. This part of the palate, known as the soft palate, is composed mainly
of skeletal muscle. Therefore, you can subconsciously manipulate the soft palate—for
instance, to yawn, swallow, or sing

Mouth The mouth includes the lips, tongue, palate, gums, and teeth.

A fleshy bead of tissue called the uvula drops down from the center of the posterior edge of
the soft palate. Although some have suggested that the uvula is a vestigial organ, it serves
an important purpose. A vestigial organ is a body structure that has lost most or all of its
original function through evolution. When you swallow, the soft palate and uvula move
upward, helping to keep foods and liquid from entering the nasal cavity. Unfortunately, it can
also contribute to the sound produced by snoring.
Two muscular folds extend downward from the soft palate on either side of the uvula.
Toward the front, the palatoglossal arch lies next to the base of the tongue; behind it, the
palatopharyngeal arch forms the superior and lateral margins of the fauces. Between
these two arches are the palatine tonsils, clusters of lymphoid tissue that protect the
pharynx. The lingual tonsils are located at the base of the tongue.

Muscles That Move the Lower Jaw
In anatomical terminology, chewing is called mastication. Muscles involved in chewing
must be able to exert enough pressure to bite through and then chew food before it is
swallowed (Figure 10.6 and Table 10.2, p. 273).
The masseter muscle is the primary muscle used for chewing because it elevates the
mandible (lower jaw) to close the mouth. It is assisted by the temporalis muscle, which
retracts the mandible.

Muscles That Move the Lower Jaw The muscles that move the lower
jaw are typically located within the cheek and originate from processes in the skull.
This provides the jaw muscles with the large amount of leverage needed for chewing.

The masseter and temporalis are responsible for elevating and closing the jaw to break food
into digestible pieces. Also, the medial pterygoid and lateral pterygoid muscles provide
support in chewing and moving food within the mouth.

Muscles That Move the Tongue

Muscles That Move the Tongue
Although the tongue is obviously essential for tasting food, it plays a vital role in mastication,
deglutition (swallowing), and speech (Figure 10.7 and Figure 10.8, p. 276). Tongue is a
muscular hydrostat, which moves in various ways with no skeletal support. Because it is so
moveable, the tongue facilitates complex speech patterns and sounds (Table 10.3, p. 274).
Figure 10.7 Muscles of the Tongue Movements (a) Lateral view shows extrinsic
muscles: styloglossus, hyoglossus, and genioglossus. (b) Anterior view shows the
palatoglossus and tongue surface structures involved in movement and sensatio

Muscles That Move the Tongue

Tongue

The Tongue
Perhaps you have heard it said that the tongue is the strongest muscle in the body. Those
who stake this claim cite its strength proportionate to its size. Although it is difficult to quantify
the relative strength of different muscles, it remains indisputable that the tongue is a
workhorse, facilitating ingestion, mechanical digestion, chemical digestion (lingual lipase),
sensation (of taste, texture, and temperature of food), swallowing, and vocalization. The
process of mechanical digestion breaks the food into small pieces using muscular activities,
such as chewing. Chemical digestion involves breaking the food down to aid digestion by
using acids and enzymes in our body fluid.
The tongue is attached to the mandible, the styloid processes of the temporal bones, and
the hyoid bone. As we discussed in Module 9 Phonation, the hyoid is unique in that it only
distantly/indirectly articulates with other bones. The tongue is positioned over the floor of the
oral cavity. A medial septum extends the entire length of the tongue, dividing it into
symmetrical halves.
Tongue muscles are classified into extrinsic or intrinsic. Extrinsic tongue muscles insert into
the tongue from outside origins. The intrinsic tongue muscles insert into the tongue from
origins within it. The extrinsic muscles move the whole tongue in different directions. The
intrinsic muscles allow the tongue to change its shape (curling the tongue in a loop or
flattening it).

Beneath its mucous membrane covering, each half of the tongue is composed of the same
number and type of intrinsic and extrinsic skeletal muscles. The intrinsic muscles (those
within the tongue) are the longitudinalis inferior, longitudinalis superior, transversus linguae,
and verticalis linguae muscles. These intrinsic and extrinsic tongue muscles allow you to
change the size and shape of your tongue, and to stick it out, respectively. Having such a
flexible tongue facilitates both swallowing and speech.

The extrinsic muscles (Figure 10.7, p. 273) of the tongue are the palatoglossus
(glossopalatine), hyoglossus, styloglossus, and genioglossus muscles. These muscles
originate outside the tongue and insert into connective tissues within the tongue. The
extrinsic muscles all include the word root glossa (glossa = "tongue"). The muscle names
are derived from where the muscle originates. The genioglossus (genio = "chin") originates
on the mandible and allows the tongue to move downward and forward.
The styloglossus originates on the styloid bone and allows upward and backward motion.
The palatoglossus originates on the soft palate to elevate the back of the tongue, and
the hyoglossus originates on the hyoid bone to move the tongue downward and flatten it.
These muscles perform three essential digestive functions in the mouth: (1) position food
for optimal chewing, (2) gather food into a bolus (rounded mass of food we form for
swallowing), and (3) position food so it can be swallowed.

Intrinsic Muscles of the Tongue Coronal and sagittal views of the intrinsic
muscles of the tongue, showing the superior and inferior longitudinal, vertical, and
transverse muscles involved in shaping tongue movements.
The top and sides of the tongue are studded with papillae, extensions of lamina propria of
the mucosa, which are covered in the stratified squamous epithelium (Figure 10.10, p.277).
Mushroom-shaped fungiform papillae cover a large area of the tongue; they tend to be larger
toward the rear of the tongue and smaller on the tip and sides. In contrast, filiform papillae
are long and thin. Fungiform papillae contain taste buds, and filiform papillae have touch
receptors that help the tongue move food around in the mouth. The filiform papillae create
an abrasive surface that performs mechanically, much like a cat’s rough tongue that is used
for grooming. Lingual glands in the lamina propria of the tongue secrete mucus and watery
serous fluid. The fluid contains the enzyme lingual lipase, which plays a minor role in
breaking down triglycerides but does not begin working until it is activated in the stomach.

The lingual frenulum

The lingual frenulum (Figure 10.5, p. 271) is a fold of mucous membrane on the underside
of the tongue that tethers the tongue to the floor of the mouth. People with the congenital
anomaly ankyloglossia, also known by the non-medical term “tongue-tie,” have a lingual
frenulum that is too short or otherwise malformed. Severe ankyloglossia could impair
feeding or cause oral-motor deficiency. Many of you may think the short lingual frenulum
could affect speech. Although it could depend on the degree of the impact on tongue mobility,
ankyloglossia seldom causes problems with speech in English speakers (Kummer, 2020).
Except for feeding difficulties, surgical management (frenulectomy) is not indicated for
speech purposes alone. Although SLPs may be the first to identify a reduced range of motion
(ROM) of the tongue, it is not in our scope of practice to diagnose ankyloglossia. When an
SLP observes potential problems with ankyloglossia, he or she may refer the client to a
physician for further examination.
Access for free at openstax.org (Sum

Ankyloglossia (Tongue-tie) Different presentations of ankyloglossia. The
heart-shaped tongue appearance (Case 1) results from a short lingual frenulum pulling
at the midline, restricting tongue movement. (Source: Gzzz, CC BY-SA 4.0
<https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons; Klaus D. Peter,
Wiehl, Germany, CC BY 3.0 DE <https://creativecommons.org/licenses/by/3.0/de/deed.en>, via
Wikimedia Commons)

Tongue This superior view of the tongue shows the locations and
types of lingual papillae

Anesthesia and the Tongue Muscles

Anesthesia and the Tongue Muscles
Before surgery, general anesthesia may be used. General anesthesia is a medically
induced state of unconsciousness with loss of sensation, awareness, and reflexes used
during surgical procedures. The normal homeostatic controls of the body are put “on
hold” so that the patient can be prepped for surgery. Control of respiration must be
switched from the patient’s homeostatic control to the control of the anesthesiologist.
The drugs used for anesthesia relax a majority of the body’s muscles.
Among the muscles affected during general anesthesia are those that are necessary
for breathing and moving the tongue. Under anesthesia, the tongue can relax and
partially or fully block the airway, and the muscles of respiration may not move the
diaphragm or chest wall. To avoid possible complications, the safest procedure to use
on a patient is called endotracheal intubation. Placing a tube into the trachea allows the
doctors to maintain a patient’s (open) airway to the lungs and seal the airway off from
the oropharynx. Post-surgery, the anesthesiologist gradually changes the mixture of
the gases that keep the patient unconscious. When the muscles of respiration begin to
function, the tube is removed. It still takes about 30 minutes for a patient to wake up,
and for breathing muscles to regain control of respiration. After surgery, most people
have a sore or scratchy throat for a few days.

The teeth

The Teeth
The teeth, or dentes (dens when talking about one tooth), are organs similar to bones that
you use to tear, grind, and otherwise mechanically break down (chew) food.

Types of Teeth

You have two sets of teeth during your lifetime (one set of teeth is called dentition). Your

20 deciduous teeth, or baby teeth, first begin to appear around 6 months of age. Between

approximately ages 6 and 12, these teeth are replaced by 32 permanent teeth. Moving

from the center of the mouth toward the side, these are as follows

Permanent and Deciduous Teeth This figure of two human dentitions
shows the arrangement of teeth in the maxilla and mandible, and the relationship
between the deciduous and permanent teeth.

The eight incisors (four each on the top and the bottom) are the sharp front teeth you
use for biting into food (used for cutting or tearing).
• The four cuspids (or canines) flank the incisors and have a pointed edge (cusp) to tear
up food. These fang-like teeth are superb for piercing tough or fleshy foods.
• Posterior to the cuspids are the eight premolars (or bicuspids), which have an overall
flatter shape with two rounded cusps useful for mashing foods.
• The most posterior and largest are the 12 molars, which have several pointed cusps used
to crush food, preparing for swallowing. The third members of each set of three molars,
top and bottom, are commonly referred to as the wisdom teeth. Their eruption is
commonly delayed until early adulthood. It is not uncommon for wisdom teeth to fail to
erupt; that is, they remain impacted (within the gums). In these cases, the teeth are
typically removed by orthodontic surgery.

Anatomy of a Tooth

Anatomy of a Tooth
The teeth are secured in the alveolar processes (sockets) of the maxilla (upper jaw) and
the mandible (lower jaw). Gingivae (commonly called the gums) are soft tissues that line
the alveolar processes and surround the necks of the teeth. Teeth are also held in their
sockets by a connective tissue called the periodontal ligament.
The two main parts of a tooth are the crown and root. The crown is the portion projecting
above the gum line, and the root is embedded within the maxilla and mandible. Both parts
contain an inner pulp cavity, containing loose connective tissue through which run nerves
and blood vessels. The region of the pulp cavity that runs through the root of the tooth is
called the root canal. Surrounding the pulp cavity is dentin, a bone-like tissue. In the root
of each tooth, the dentin is covered by an even harder bone-like layer called cementum.
In the crown of each tooth, the dentin is covered by an outer layer of enamel, the hardest
substance in the body

Structure of the Tooth This longitudinal section through a molar in its
alveolar socket shows the relationships between enamel, dentin, and pulp.
Although enamel protects the underlying dentin and pulp cavity, it is still nonetheless
susceptible to mechanical and chemical erosion, or what is known as tooth decay. The
most common form, dental caries (cavities), develops when colonies of bacteria feeding
on sugars in the mouth release acids that cause soft tissue inflammation and degradation
of the calcium crystals of the enamel. The intra-oral structures play important roles in our
verbal communication, and they are essential for mastication and deglutition. The digestive
functions of the mouth are summarized in Table 10.4, p. 281. We will explore the structures
and functions of swallowing further in the next module.

Facial Bones of the Skull

Facial Bones of the Skull
The facial bones of the skull form the upper and lower jaws, the nose, nasal cavity and
nasal septum, and the orbit. The facial bones include 14 bones, with six paired bones and
two unpaired bones. The paired bones are the maxilla, palatine, zygomatic, nasal, lacrimal,
and inferior nasal conchae bones. The unpaired bones are the vomer and mandible bones.
Although classified with the brain-case bones, the ethmoid bone also contributes to the
nasal septum and the walls of the nasal cavity and orbit.

Maxillary Bone

Maxillary Bone
The maxillary bone, often referred to simply as the maxilla (plural = maxillae), is one of a
pair that together form the upper jaw, much of the hard palate, the medial floor of the orbit,
and the lateral base of the nose (Figure 10.14, p. 283). The curved, inferior margin of the
maxillary bone that forms the upper jaw and contains the upper teeth is the alveolar
process of the maxilla (Figure 10.13, p. 282). Each tooth is anchored into a deep socket
called an alveolus. On the anterior maxilla, just below the orbit, is the infraorbital foramen.
The prefix "infra-" is derived from Latin and means "below" or "beneath" in position or level.
This is the point of exit for a sensory nerve that supplies the nose, upper lip, and anterior
cheek. On the inferior skull, the palatine process from each maxillary bone can be seen
joining together at the midline to form the anterior three-quarters of the hard palate (Figure
10.16, p. 284). The hard palate is the bony plate that forms the roof of the mouth and floor
of the nasal cavity, separating the oral and nasal cavities.

Maxillary Bone The maxillary bone forms the upper jaw and supports the
upper teeth. Each maxilla also forms the lateral floor of each orbit and the majority of the
hard palate.

Skull: Anterior View An anterior view of the skull shows the bones that form
the forehead, orbits (eye sockets), nasal cavity, nasal septum, and upper and lower jaws.
An enlarged view of this image is on Fi

Skull: Lateral View The lateral skull shows the large, rounded brain case,
zygomatic arch, and upper and lower jaws. The zygomatic arch is formed jointly by the
zygomatic process of the temporal bone and the temporal process of the zygomatic bone. The
shallow space above the zygomatic arch is the temporal fossa. The space inferior to the
zygomatic arch and deep to the posterior mandible is the infratemporal fossa.

Skull: External and Internal Views (Transverse Plane) (a) The hard palate is
formed anteriorly by the palatine processes of the maxilla bones and posteriorly by the
horizontal plate of the palatine bones. (b) The complex floor of the cranial cavity is formed by
the frontal, ethmoid, sphenoid, temporal, and occipital bones. The lesser wing of the sphenoid
bone separates the anterior and middle cranial fossae. The petrous ridge (petrous portion of
temporal bone) separates the middle and posterior cranial fossae

Palatine Bone

Palatine Bone
The palatine bone is one of a pair of irregularly shaped bones that contribute small areas
to the lateral walls of the nasal cavity and the medial wall of each orbit. The largest region
of each of the palatine bones is the horizontal plate. The plates from the right and left
palatine bones join together at the midline to form the posterior quarter of the hard palate
(Figure 10.16, a, p. 284). Thus, the palatine bones are best seen in an inferior view of the
skull and hard palate.

Zygomatic Bone

Zygomatic Bone
The zygomatic bone is also known as the cheekbone. Each of the paired zygomatic bones
forms much of the lateral wall of the orbit and the lateral-inferior margins of the anterior
orbital opening (Figure 10.14, p. 283). The short temporal process of the zygomatic bone
projects posteriorly, where it forms the anterior portion of the zygomatic arch (Figure 10.15,
p. 283)

Nasal bone

Nasal Bone
The nasal bone is one of two small bones that articulate (join) with each other to form the
bony base (bridge) of the nose. They also support the cartilages that form the lateral walls
of the nose (Figure 10.17). These are the bones that are damaged when the nose is broken.

Skull: Sagittal Plane This mid-sagittal view of the skull shows the nasal septum

Ethmoid Bone

Ethmoid Bone The unpaired ethmoid bone is located at the midline within the
central skull. It has an upward projection, the crista galli (Latin: “crest of the rooster”), and a
downward projection, the perpendicular plate, which forms the upper nasal septum. The
cribriform plates form both the roof of the nasal cavity and a portion of the anterior cranial fossa
floor. The lateral sides of the ethmoid bone form the lateral walls of the upper nasal cavity, part
of the medial orbit wall, and give rise to the superior and middle nasal conchae. The ethmoid
bone also contains the ethmoid air cells.

Nasal Cavity

Nasal Cavity: Lateral Wall The three nasal conchae are curved bones that project
from the lateral walls of the nasal cavity. The superior nasal concha and middle nasal concha are
parts of the ethmoid bone. The inferior nasal concha is an independent bone of the skull.

Lacrimal Bone

Lacrimal Bone
Each lacrimal bone is a small, rectangular bone that forms the anterior, medial wall of the
orbit (see Figure 10.14 and Figure 10.15, p. 283). The anterior portion of the lacrimal bone
forms a shallow depression called the lacrimal fossa. Extending inferiorly from lacrimal
fossa is the nasolacrimal canal. The lacrimal fluid (tears of the eye), which serves to
maintain the moist surface of the eye, drains at the medial corner of the eye into the
nasolacrimal canal. This duct then extends downward to open into the nasal cavity, behind
the inferior nasal concha. In the nasal cavity, the lacrimal fluid normally drains posteriorly,
but with an increased flow of tears due to crying or eye irritation, some fluid will also drain
anteriorly, thus causing a runny nose

Inferior Nasal Conchae

Inferior Nasal Conchae
The right and left inferior areas of nasal conchae form a curved bony plate that projects into
the nasal cavity space from the lower lateral wall (see Figure 10.19, p. 286). The inferior
concha is the largest of the nasal conchae. It can easily be seen when looking into the
anterior opening of the nasal cavity.

Vomer Bone

Vomer Bone
The unpaired vomer bone often referred to simply as the vomer, is triangular-shaped and
forms the posterior-inferior part of the nasal septum (see Figure 10.17, p. 285). The vomer
is best seen when looking from behind into the posterior openings of the nasal cavity (see
Figure 10.16a, p. 284). In this view, the vomer is seen to form the entire height of the nasal
septum. A much smaller portion of the vomer can also be seen when looking into the anterior
opening of the nasal cavity.

Mandible

Mandible
The mandible forms the lower jaw and is the only moveable bone of the skull. At the time of
birth, the mandible consists of paired right and left bones, but these bones fuse together
during the first year to form the single U-shaped mandible of the adult skull. Each side of the
mandible consists of a horizontal body, and posteriorly, a vertically oriented ramus of the
mandible (ramus = “branch”). The outside margin of the mandible, where the body and
ramus come together, is called the angle of the mandible (

The ramus on each side of the mandible has two upward-going bony projections. The more
anterior projection is the flattened coronoid process of the mandible, which provides
attachment for one of the biting muscles. The posterior projection is the condylar process
of the mandible, which is topped by the oval-shaped condyle. The condyle of the mandible
articulates (joins) with the mandibular fossa and articular tubercle of the temporal bone.
Together, these articulations form the temporomandibular joint, allowing the opening and
closing of the mouth (Figure 10.15, p. 283). The broad U-shaped curve located between the coronoid and condylar processes is the
mandibular notch. Important landmarks for the mandible include the following.

Alveolar process of the mandible

Alveolar process of the mandible—This is the upper border of the mandibular body
and serves to anchor the lower teeth.

• Mental protuberance

• Mental protuberance—The forward projection from the inferior margin of the anterior
mandible that forms the chin (mental = “chin”).

Mental foramen

Mental foramen—The opening is located on each side of the anterior-lateral mandible,
the exit site for a sensory nerve that supplies the chin.

Mylohyoid line

Mylohyoid line—This bony ridge extends along the inner aspect of the mandibular
body (see Figure 10.17, p. 285). The muscle that forms the floor of the oral cavity
attaches to the mylohyoid lines on both sides of the mandible.

Mandibular foramen

Mandibular foramen—This opening is located on the medial side of the ramus of the
mandible. The opening leads into a tunnel that runs down the length of the mandibular
body. The sensory nerve and blood vessels that supply the lower teeth enter the
mandibular foramen and then follow this tunnel. Thus, to numb the lower teeth prior to
dental work, the dentist must inject anesthesia into the lateral wall of the oral cavity at a
point where this sensory nerve enters the mandibular foramen.

Lingula

Lingula—This small flap of bone is named for its shape (lingula = “little tongue”). It is
located immediately next to the mandibular foramen, on the medial side of the ramus.
A ligament that anchors the mandible during the opening and closing of the mouth
extends down from the base of the skull and attaches to the lingula.

Mandible The mandible is the only moveable bone of the skull.

Lateral View of the Human Facial Skeleton with a horizontal reference
line drawn from the lower border of the orbit to the upper margin of the ear canal. (Source:
Copyright 1989 by Department of Audiology & Speech Pathology Memphis State
University, Memphis, Tennessee From the W.R. Zemlin Memorial
Website http://zemlin.shs.uiuc.edu Used with permission)
The lateral view of the human facial skeleton above shows an example of the normal
dentition and occlusion of the upper and lower teeth. There are several different
classifications of occlusion. Some of them could cause various challenges in verbal
communication (“Angle’s classification, 1899,” explained in Zemlin, 1998). The following
three classes are common.
• Class I normal occlusion
• Class II malocclusion: Overjet. Upper teeth are located ahead of the mandible, often
presenting the appearance of a receding chin.

• Class III malocclusion: lower teeth are located ahead of the maxillary incisors,
presenting the appearance of a prognathic jaw.

NOTE: The term “overjet” or “underjet” refers to the protrusion outward horizontally, while
“overbite” or “underbite” refers to the vertical overlap of the upper and lower teeth out of
normal limits.
Figure 10.22 Illustration of overbite and overjet Overjet (or underjet) refers to the
horizontal protrusion between upper and lower front teeth, while overbite (or underbite)
refers to their vertical overlap beyond normal limits. (Source: Download from Wikimedia
Commons: at https://commons.wikimedia.org/w/index.php?search=overjet&title=Special:MediaSearch&go=Go&type=image)

Physiology of Articulation and Resonance

Physiology of Articulation and Resonance
Articulators work rapidly in succession to make our verbal communication meaningful. Let’s
consider the articulators and vocal tracts contribution in vowels and consonants production
separately. Vowels of English are all produced with the oral tract open. The levator veli
palatini and muscular uvulae are primary muscles for closing the nasal tract for oral sound
production.
If the nasal tract does not close sufficiently, hypernasality in speech occurs. Individuals with
cleft palate often experience incomplete closure of the nasal tract, result in hypernasality in
speech. Hypernasality often interferes with the intelligibility of speech. In contrast,
individuals who cannot open their nasal tract, potentially due to allergies or a head cold, may
sound hyponasal. For vowel production, we move speech articulators horizontally and
vertically to make distinctions in vowels.

Five factors generally classify consonants. The main three factors of the five are voicing
features (voiced or unvoiced), place of articulation, and manner of articulations (Remember:
VPM – V for "Voice," P for "Place," and M for "Manner" of articulation). We vibrate our vocal
folds for voiced sounds. If you touch your neck with your hand and say “bin,” you will feel
the vibration on your hand at the beginning of the word. If you say “pin” in the same way,
you do not feel the vibration on your hand at the beginning of your production because the
/p/ in the word “pin” is a voiceless phoneme.
Place of articulation refers to the location of the speech articulators when each phoneme is
produced. In English, the places of articulation are bilabial (both lips), labio-dental (upper
teeth and lower lip – think lip and teeth), inter-dental (upper and lower teeth – between the
teeth), alveolar (alveolar ridge), post- or palate-alveolar (behind the alveolar ridge), velar
(posterior part of the soft palate), and glottis (vocal-folds level). Manner of articulation refers
to the way with which each phoneme is produced.
The workings of the articulation and resonance organs involve coordination and timing with
two other subsystems of speech production, including respiration and phonation.

Role of Articulation and Resonance in Communication

Role of Articulation and Resonance in Communication
Figure 10.23 Articulation and Resonance: One of the three Subsystems of Speech
Production: This illustration shows the articulation and resonance as the subsystem to
shape up speech from the voice produce as its "source" by two other subsystems of speech
production, respiration and phonation
Articulation and resonance are “filter” functions in our verbal communication. The filter
functions transform the voice into meaningful utterances. Articulation could be disrupted due
to neurogenic insults that interfere with the ability to plan and program the movements of
speech articulators

In some cases, children do not develop proper movements of speech articulators because
of various causes, such as Cerebral Palsy, Childhood Apraxia of Speech (CAS), Autism
Spectrum Disorders (ASD), and Chromosome disorders, such as Down Syndrome.
The effects of early intervention are widely reported. Speech-Language Pathologists (SLPs)
work with young children to guide them through speech sound development to improve
communicative competence. We acquire speech sounds in sequence. Utilizing the
published developmental normative information, SLPs facilitate movements of speech
articulators for young clients to develop intelligible speech.
Resonance disorders present with hypernasality, hypo nasality, cul-de-sac resonance, or a
combination of two or more of those. The structural causes of resonance disorders are
generally due to cleft lips, cleft palate, both cleft lips and palate, or other craniofacial
disorders. These structural differences could be attributable to genetic factors or secondary
to other conditions. In these cases, SLPs work in inter-professional teams to guide clients
with proper behavioral management for verbal communication before or after the care of
other professionals, such as cleft-repair surgeries.

Cleft Lip and Palate Illustration of unilateral and bilateral cleft lip
and palate, showing variations in the location and extent of the cleft affecting
the lip and roof of the mouth. (So

SLPs often implement restorative approaches first. With restorative approaches, SLPs
intend to restore or develop communication by behavioral remediation. When restorative
approaches are not applicable, SLPs take substitutive approaches. In some cases, SLPs
may support a combination of oral communication and the use of an Alternative
Augmentative Communication (AAC) device to support functional communication.
Resonance disorders could occur without structural deviation due to velopharyngeal
mislearning of the sound production presented for certain phonemes or in certain situations
of phoneme production. If this is the case, SLPs provide behavioral guidance to facilitate
proper re-learning of the phoneme production. Velopharyngeal mislearning is confirmed by
assessing for anatomical differences through an endoscopy of speech structures that
examines structure and function and objective examination of produced speech.

Cleft Lip and Cleft Palate

Cleft Lip and Cleft Palate
During embryonic development, the right and left maxilla bones come together at the
midline to form the upper jaw. At the same time, the muscle and skin overlying these bones
join together to form the upper lip. Inside the mouth, the palatine processes of the maxilla
bones, along with the horizontal plates of the right and left palatine bones, join together to
form the hard palate. If an error occurs during these developmental processes, atypical
development, such as a cleft lip or cleft palate, may result.
Cleft lip is a common developmental condition that affects approximately 1 in 1,000 births,
with a higher incidence in males. This condition involves a partial or complete failure of
the right and left portions of the upper lip to fuse, leaving a cleft (gap).
A more severe developmental defect is cleft palate, which affects the hard palate. The
hard palate is the bony structure that separates the nasal cavity from the oral cavity. It is
formed during embryonic development by the midline fusion of the horizontal plates from
the right and left palatine bones and the palatine processes of the maxilla bones. Cleft
palate affects approximately 1 in 2,500 births and is more common in females. It results
from a failure of the two halves of the hard palate to completely come together and fuse
at the midline, thus leaving a gap between them. This gap allows for communication
between the nasal and oral cavities. In severe cases, the bony gap extends into the
anterior upper jaw, where the alveolar processes of the maxilla bones also fail to join
together above the front teeth properly. If this occurs, a cleft lip will also be seen. Because
of the communication between the oral and nasal cavities, a cleft palate makes it very
difficult for an infant to generate the suckling needed for nursing, thus leaving the infant at
risk for malnutrition. Surgical repair is required to correct cleft palate defects.

Bolus

bolus (p. 275) mass of chewed food

Crown

crown (p. 280) portion of tooth visible superior to the gum line

Cuspid

(p. 279) (also, canine) pointed tooth used for tearing and shredding food

deciduous teeth

(p. 278) “baby teeth” (20 in total)

Dentin

(p. 280) bone-like tissue immediately deep to the enamel of the crown or cementum
of the root of a tooth

Dentition

(p. 278) set of teeth

enamel

p. 280) covering of the dentin of the crown of a tooth

Fauces

(p. 271) opening between the oral cavity and the oropharynx

gingivae

(p. 280) gums.

Labia

(p. 268) lips. singular = labium

lingual frenulum

(p. 276) mucous membrane fold that attaches the bottom of the tongue
to the floor of the mouth

lingual lipase

(p. 276) digestive enzyme from glands in the tongue that acts on triglycerides

molar

(p. 279) tooth used for crushing and grinding food

oral cavity

(p. 267) (also, buccal cavity) mouth

oral vestibule

(p. 271) part of the mouth bounded externally by the cheeks and lips, and
internally by the gums and teeth

palatoglossal arch

(p. 272) muscular fold that extends from the lateral side of the soft
palate to the base of the tongue

palatopharyngeal arch

(p. 272) muscular fold that extends from the lateral side of the soft
palate to the side of the pharynx

permanent teeth

(p. 278) adult teeth (32 in total)

premolar

(p. 279) (also, bicuspid) transitional tooth used for mastication, crushing, and
grinding food

pulp cavity

(p. 280) deepest portion of a tooth, containing nerve endings and blood vessels

Root

(p. 280) portion of a tooth embedded in the alveolar processes beneath the gum line

soft palate

(p. 271) posterior region of the bottom portion of the nasal cavity that consists
of skeletal muscle

tongue

(p. 275) accessory digestive organ of the mouth, the bulk of which is composed of
skeletal muscle

oral tract,

nasal tract

epicranial aponeurosis,

occipitofrontalis (frontal belly),

corrugator supercilio,

orbicularis oculi, o

ccipitofrontalis (occipital belly),

orbicularies oris, buccinator

styloglossus,

genioglossus,

hyoglossus,

palatoglossus

temporalis,

masseter,

area of superficial muscle dissection,

lateral pterygoid,

medial pterygoid

superior longitudinal muscle,

verrical muscles,

transverse muscles,

inferior longitudinal muscle

] Of the two vocal tracts, we use ________ tract to produce oral
phonemes and use _________ tract to produce nasal phonemes.

oral, nasal

The __________ is a circular muscle that moves the lips.

orbicularis oris

The ________ muscle is the primary muscle used for chewing
because it elevates the mandible to close the mouth.

masseter

The __________ refers to the upper jaw.

maxilla

The __________ refers to the lower jaw.

mandible

Two primary muscles that elevate the soft palate and close the
velopharyngeal port are ________________ and _______________.

levator veli palatini; muscular uvulae