By U. Hamlar. University of Maine.
The lower border is of fibrous tissue that is reinforced by accessory liga- attached around the neck of the condyloid process quality silagra 50 mg, ments buy silagra cheap online, which strengthen it cheap 100mg silagra with visa. It attaches to the zygo- with a synovial membrane that surrounds the bones matic arch and is directed obliquely down and poste- and their articulating surfaces. It has no counterpart medially, and fibrous covering of the articulating surfaces and center seemingly none is needed since the right and left tem- of the disc that lack a blood supply. Posteriorly, the disc and the capsule are connected by a thick pad of loose elastic vascular connective tis- 3. Therefore, the disc can follow the is closed but becomes tense on extreme protrusion of movement of the condyle when the muscles (lateral the mandible. This design of attachments gives each disc freedom to move anteriorly but limits it from excessive forward 4. It gives of the condyle of the mandible on wide openings as it some support to the mandible and may help limit maxi- becomes taut. It is attached superiorly to the 404 Part 3 | Anatomic Structures of the Oral Cavity joint is at about the same level as the occlusal plane at birth with relatively no ramus height (Fig. During growth, the articular fossa deepens, the articu- lar eminence becomes prominent, the condyle becomes rounded, and the shape of the disc changes to conform to the change in shape of the fossa and condyle. The condyle con- tains cartilage beneath its surface, and the condyloid process and ramus lengthen until a person is 20 to 25 years old. As a result of growth in the condyle area, the body of the mandible is lowered from the skull, and the occlusal plane is located about 1 in. Notice that the mandibular The average width of the condyle and its depth beneath condyle is barely higher than the crest of the mandibular ridge. The condyle is a large solid structure, about 10 mm thick anteropos- angular (sphenoidal) spine of the sphenoid bone and teriorly and 20. Although fans out inferiorly to attach on the lingula of the man- the average depth of the outer surface of the condyle is dible near the mandibular foramen. Depth (beneath the skin) of the land- marks of the head of the mandibular condyle, and relative direction of the lateral pterygoid muscle fibers (red arrows) from the insertion on the neck of the con- dyle toward the origin (not seen, but on the lateral surface of the lateral plate of the sphenoid bone). The location of the center of rotational opening of the mandible [the hinge axis] was found to pass through or near the center of the heads of the condyles. Resultant articu- lar settings were found to be wider than the outer poles of the condyles. This means that lateral and protrusive excursions are controlled by ligaments and muscles, rather than by bone, as previously reported. Woelfel and Igarashi and supported by the Ohio State University College of Dentistry and Nihon University School of Dentistry in Tokyo. The anterior part of the capsule that surrounds the entire Notice that when you open and close the mandible mandibular fossa and articular eminence attaches 10 mm just a little, you feel little movement of the con- in front of the crest of the articulating eminence. Next, move the fit, notice the space between the mandibular your jaw to the right and left sides. You are feel- condyles and the articular fossae when the pos- ing the movement of the outer (lateral) surface of terior teeth are in tight occlusion. You are feeling the upper and posterior index fingers immediately in front of either portion of the mandibular condyle, especially when ear opening and open and close your mouth. In the anterior three quarters of the the mandibular fossa of the temporal bone mandibular fossa called the articular fossa b. In the posterior quarter of the mandibular the mandibular fossa of the temporal bone fossa called the articular fossa c. On the posterior inferior portion of the the mandibular fossa of the sphenoid bone articular eminence d. On the anterior inferior position of the the mandibular fossa of the sphenoid bone articular eminence e. The ligament that limits the amount of movement of the mandible and attaches from the inferior surface of the neurocranium to the lingula of the mandible is the a. The following general terms relate to muscles and will cle fibers make up a bundle, and various numbers of be helpful to know as you read this section: bundles comprise a muscle. Each contractile bundle structure of cells can contract about 57% of its fully stretched Depressor: acts to depress or make lower length. Many fibers contracting produce like the labial surface of a tooth greater power as needed. Mental: referring to the chin; the mental foramen is When a muscle maintains its length as it contracts to the hole in the mandible where the mental nerve passes stabilize a part, this movement is called isometric con- out of the mandible to the chin; the mentalis muscle traction. If orbit you maintain contact of all of your teeth but squeeze Origin (of a muscle of mastication): is the source, them together hard, these same muscles are contract- beginning or fixed proximal end attachment of a mus- ing isometrically because they cannot shorten any more cle as compared to its insertion, which is a muscle’s once your teeth are together. As you read this, the muscles by pulling or by shortening, never by pushing or by of mastication are probably in a state of minimal tonic lengthening. Skeletal or voluntary muscles are made up contraction or balance with each other, with the neck of specialized cells that contract. Skeletal muscles are muscles, and with gravity, enabling a comfortable, rest- very active metabolically and therefore require a rich ful position for your mandible with the teeth apart. Individual muscle cells are small, elongated con- When you fall asleep at your desk, antigravity muscles tractile fibers, each enclosed in a delicate envelope of relax and, as you may have seen on others, the mouth loose connective tissue. Chapter 14 | Structures that Form the Foundation for Tooth Function 407 muscle (on 25 males is 30. Origin: The masseter arises from the inferior and They include four pairs of muscles (right and left): medial surfaces of the zygomatic arch that is made up of masseter, temporalis, medial pterygoid, and lateral ptery- the zygomatic bone, the zygomatic process of the max- goid muscles. These muscles have the major control over illae, and the temporal process of zygomatic bone (seen the movements of the mandible. From here, it extends inferiorly and pos- one end identified as its origin and the other end identi- teriorly toward its insertion. The origin end of each of the muscles Insertion: The masseter inserts on the inferior of mastication is the source, beginning, or fixed proximal lateral surface of the ramus and angle of the mandible attachment located, in this case, on the bones of the neu- (Fig. The insertion Action: It elevates the mandible (closes the mouth) end is the attachment on the movable bone that for each 6,8,9 and applies great power in crushing food. Its aver- age volume is over twice that of the medial pterygoid Parietal bone Frontal bone Zygomatic bone Temporalis m. Masseter muscle (shaded red) and Mandible fan-shaped temporalis muscle (shaded blue). Human skull, left side, showing location of some attachments of the temporalis (outlined in blue) and masseter muscles (shaded red). This lateral view shows the origin of the fan-shaped temporalis muscle (within the shallow temporal fossa outlined with a blue dotted line), and the origin of the masseter (light red area on the zygomatic arch) as well as the insertion of the masseter muscle light red area on the (lateral surface of the angle of the mandible). The red arrows indicate the slope of the posterior surface of the articular eminence and the subsequent downward (opening) movement of the mandible when it is pulled forward by both lateral pterygoid muscles.
These radiographs show antemortem (top) and postmortem (bottom) radiographs of a homicide victim with orthodontic appliances in place order 100 mg silagra otc, which are identical to actual postmortem findings (seen in B and C) and served to confirm the identity order silagra paypal. This postmortem photograph shows the orthodontic retainer in the mandibular arch as evident in the antemortem radiographs purchase generic silagra. This postmortem photograph shows the orthodontic retainer B in the maxillary arch as evident in the antemortem radiographs. Some dentists mount radiographs as viewed from the front of the patient (with the film bump facing toward the viewer), which is the standard in forensic dentistry, while others still prefer mounting them as viewed from the lingual (film bump facing away from the viewer). Charting tooth identification in dental offices (the antemor- tem record) is not always done using the Universal system. However, 20 of the 33 to obtain swabbings of bite marks or other human tissues for known victims were identified through their dental comparison to antemortem records. Due to the focus of this text (the relevance of dental anat- omy), only brief comments will be made about these topics. In civil litigation cases, a person might claim that improper dental care was rendered (malpractice) as illustrated in the radiographs in Figure 12-6; damage was sustained at the hands of another person (criminal assault and battery); damage was sustained due to food contaminated with a foreign body (glass, shell, etc. One can see marginal discrepancies between tooth contours and restoration contours (especially on the forensic dentist. This is a Panorex (panoramic) radiograph of a 14-year-old girl showing rampant caries that progressed over many years resulting in a treatment recommendation to extract all teeth. This evidence of parental neglect was reason for the dentist to contact legal authorities for suspected child abuse/ neglect. This is a photograph of this same 14-year-old girl B showing rampant dental caries. All of the techniques and careful comparisons situation was reported immediately to the appropriate described previously are useful. The dentist’s suspicions had Dentists and other health caregivers have a respon- been aroused sufficiently regarding the incongruity of sibility to report suspected abuse and neglect of their the story and the injuries sustained. This includes recognition and dif- treatment, the police arrived, and the man was arrested. One abuse scenario is observe include fractured bones and teeth, bruises, lac- described here. As often seen by this woman was silent while the man related an accident author, children may not be taken to a dentist for treat- as the cause of the injuries. This can result in pain and infec- present during the treatment and was evasive about tion and, in some cases, may result in the loss of all answering questions. Color and black-and-white film photography is buckles, and other blunt objects such as a hammer or still the standard, but digital photography has become pipe. The use of infrared photography solved by bite mark identification, analysis, and com- can be used to identify subcutaneous evidence of dam- parison. Many bites are severe and leave telltale marks age from a bite mark that is not visible on the surface of long after an assault. Ultraviolet photography can serve to depict a parison and analysis is shown here, comparing bite bite mark in an area with extraneous other marks such mark tracings to the tooth imprint pattern tracings of as tattoos and skin damage. Dental casts and photographs The forensic dentist must first establish the mark as from the suspect or suspects are made after obtaining a a human bite mark, and then identify, if possible, the court-ordered search warrant (Fig. Aberrations include teeth In all cases of bite mark analysis, the forensic dentist that are missing, extruded (supererupted), hypo- must have a thorough knowledge and understanding of erupted or ankylosed, rotated (torsiversion), tilted, tooth morphology, occlusion, dental arch characteris- chipped, and anomalous. Teeth that are anomalies should be reason enough to remain open- malpositioned, not in occlusion, fractured, or restored minded and diligent when considering bite marks! This deviation from normal (or the possibility of animal bites, victim self-bites, and differences from one suspect to another) could benefit marks from foreign objects that might be mistaken for the forensic dentist in analysis and identification. Separate analysis of those markings may Although these techniques can be useful in solving be useful to law enforcement agencies by connecting some child abuse cases, assaults, and homicide, bite the victim’s injuries to a tool or instrument owned by marks cannot generally be used to a level of absolute a suspect. A photograph of the dentition of the perpetrator of child abuse of a 2-year-old girl resulting in her death. Models of the suspect show a distinct dental pattern that matches well to the injuries depicted in C. This photo- graph shows the bite marks on the victim depicting the relationship of the maxillary teeth as shown in A and B. Law enforcement agencies are becoming increasingly After alerting investigators, the body was exhumed and aware of potential identifications from the dental pro- studied with the resultant identification and convic- fession. In a landmark bite mark case in California, tion of the murderer based on the victim’s nose bite State v. Thus, the dentition has not been scientifically established, (2) the reliability of this method of identification was legally ability of the teeth to transfer a truly unique pattern verified. As a result of this report, the field of forensic den- An important development in forensic sciences was tistry is now working toward establishing increased the report of the National Academy of Sciences in 2009 scientific validity for human bite marks so that the evi- titled Strengthening Forensic Science in the United dentiary value is adequate for jurisprudence purposes. This is an exhaustive report on However, in the mean time, bite marks continue to all the forensic sciences and focused on the improve- remain a serious and important tool in criminal inves- ment of the entire field. However, there are many natu- A forensic dental team must be trained at the individ- ral disasters that cause mass fatalities. The Southwest Symposium is the Indian Ocean, and other hurricanes, earthquakes, offered biannually in June at the University of Texas Health floods, and tornados. Additionally, the American Society of Forensic building collapses, large freeway motor vehicle acci- Odontology (http://www. Mass disasters cannot be predicted with any courses nationally and internationally. All forensic den- accuracy, but they will certainly continue to happen in tists and teams who were initially called to New York our immediate future and beyond. Knowledge of board certified by the American Board of Forensic dental anatomy is crucial to this role. The In the event of a mass disaster, local law enforcement management of any size disaster will necessarily include agencies and emergency medical teams respond first. Site secu- that the forensic dentist and the dental team are well rity is the first priority for the law enforcement agency. Chapter 12 | Forensic Dentistry 355 The initial response may include the mobilization of depicts the dental radiographs and actual dissected federal and statewide assistance. It is a database program that utilizes It is critical for a dentist to be available at the disaster specific codes of antemortem and postmortem dental site to identify human remains and dental components findings and identifies records that have a possible of human remains that may not be recognizable by a identification match. This onsite during the entire operation of search and recov- program can be downloaded at no cost from http:// ery. A general recommendation is to The personnel in charge of antemortem records have a forensic dentist accompany each body recovery obtain antemortem dental records from dentists of team to ascertain that all relevant dental information likely victims. These records must include copies of all necessary for identification is retained in a useful and dental chart information and notations, as well as origi- trackable manner. All body parts are initially flagged nal dental radiographs that are identified by name, date, on site and in situ, then photographed in place prior to and position (left, right, etc. This will stabilize the fragile The dental radiographs alone are not adequate to dental evidence from damage during transport. One must also consider All body parts are given separate identification num- the time span between antemortem information and the bers, which will often mean that several parts of a single presumed time of death.
Retentive grooves may be prepared and bonding purchase silagra no prescription, there is less need for internal retention buccally and lingually in a proximal box as extensions grooves buy 50mg silagra mastercard. These retentive grooves are designed to toward the occlusal (seen on a die for a cast metal prevent the amalgam restoration from dislodging in a onlay in Fig effective silagra 100mg. They are located at the axiobuc- occlusodistal inlay preparation must converge slightly cal (A-B) and axiolingual (A-L) line angles seen best toward the occlusal. Resin restorations are generally pre- restoration can be refined outside of the mouth and then pared in a similar fashion to amalgam. The underlying lesion causes overlying enamel to appear slightly darker or more opaque than surrounding, sound enamel. These changes are most evident when a source of light (such as fiber optics) is placed lingually against the proximal enamel of the tooth, revealing the change in translucency facially (Fig. The line on the die marks the cavosurface margin that ends with a continuous bevel. Sometimes, how- ever, a more defined, traditional preparation may be incisal, and axial (as abbreviated in Fig. The three walls are the facial, lingual, and gingival walls, and the fourth wall (or floor) is the axial. Subsequently, this preparation has six inter- nal line angles: facioaxial, linguoaxial, gingivoaxial, faciolingual, linguogingival, and gingivofacial. There are only three internal point angles: faciolinguoaxial (abbreviated F-L-A in Fig. A light source is directed through the proximal surfaces of these anterior teeth to reveal a amalgam approached from the lingual on the distal of change in translucency just cervical to the proximal contact tooth No. The confusion with “L,” which is used to denote the lingual approach for removing the decay, whenever possible, is surface. Retentive grooves are evident at the cavosurface of the gingivoaxial and incisoaxial line angles. Note the slight convergence of the incisal and gingival wall toward the lingual for reten- tion. This preparation also has a retentive groove (in the shadow between G and A) at the gingivoaxial line angle, but it does not extend to the cavosurface. Retentive features are found internally at the axiogingival line angle and the faciolinguoaxial point angle. Key for nomenclature: for lingual approach (A and B): G, gingival; A, axial (blue); F, facial; I, incisal. Examples of the angles are the retentive features G-A and I-A for the gingivoaxial and incisoaxial line angles, respectively. Key for the facial approach (C): F, facial; A, axial (blue); G, gingival; L, lingual. However, the more patient’s concern for esthetics are important factors conservative method of affording retention and reduc- when deciding whether or not to restore the tooth. These two portions may join at an angle called occurs when the tooth corner fractures off due to a blow the axiogingival line angle. The loss of an incisal angle is plainly vis- A composite restoration that restores one incisal ible upon clinical examination. An alternative as always, must be analyzed to be sure that there is treatment is a veneer of porcelain bonded to the facial room for the restoration when the patient chews and surface of the tooth, replacing the fractured incisal area incises, especially in a protrusive direction. If the preparation is most commonly achieved by acid-etch techniques that permit resin tags to bond the composite to the tooth. A thin overlapping sleeve of excess composite mate- rial can cover beveled enamel that has been acid etched to maximize retention (Fig. View of the lesion showing the of curvature, adjacent to the gingiva, where the natural gingival and axial portions of the defect. After smoothing the cleansing action of the lips, tongue, and cheeks is inef- preparation and acid etching the enamel, the restored tooth with a sleeve (thin layer of bonded resin) that overlaps the fective. This area of the tooth is susceptible to plaque etched enamel surface, thus establishing maximum retention accumulation and resultant caries. Incipient (beginning) facial lesion that is seen as chalky and discolored and is flaking away. An obvious cavitated class V facial lesion that has destroyed much of the enamel on the buccal surface of the crown and adjacent cementum and dentin of the root. Class V demineralization: a chalky white area (arrows) seen in the cervical third of a maxillary lateral incisor with incisal wear is evidence of the first stages of dental caries. If this demineralization continued and did not reverse itself (through excellent oral hygiene, diet, and use of topical fluoride), this area could develop a cavitation (hole) that would need to be restored. Also, notice the inflammation of the adjacent gingiva (gingivitis), which is also caused by bacterial plaque. As with a radiograph of a class I lesion, the class V With decreased salivary flow and/or poor oral hygiene, lesion is superimposed over buccal or lingual surfaces the incidence and severity of caries increase in this area of enamel that show up whiter (radiopaque), thereby (Fig. As a class V lesion begins to form, it appears as a By the time a class V lesion is evident on radiographs, chalky white or stained surface (Fig. In these it has progressed far beyond the incipient stage and beginning (incipient) lesions, care should be taken with will require a much larger restoration than would have the explorer not to break through an area of beginning been required if it were clinically diagnosed at its earli- demineralization that has not yet cavitated since excel- est stages. Therefore, the examiner should not depend lent oral hygiene and fluoride have been shown to on radiographs for detection of these lesions. These lesions may be hid- when discovering a cervically located radiolucency den slightly apical to the level of inflamed gingiva so on a radiograph, the dentist should carefully evaluate that the use of the tactile sense obtained through the the tooth to clinically prove or disprove the presence explorer is critical for detection of cavitation9 and for distinction between these lesions (which are cavitated) and a calcified buildup of calculus (which is felt as a bump attached to the surface of the tooth). Other areas of cavitation (or depressions) located in the cervical of the crown and the adjacent root sur- face include defects formed from erosion by acids, or from abrasion (most commonly caused by abrasive toothpastes and improper tooth brushing [as seen in Fig. Maxillary anterior teeth showing cervical sion, the cementum, which is much less mineralized abrasion, possibly due to poor tooth brushing technique and than enamel, is more susceptible to caries compared abrasive pastes. Each tooth should be evaluated carefully to is occurring more frequently in our aging population determine if application of a desensitizing solution or a (Fig. Chapter 10 | Treating Decayed, Broken, and Missing Teeth 315 decay could respond to fluoride and improved oral hygiene and actually remineralize so that no restoration is required. Also, these defects could be areas of arrested (old, inactive) decay, or noncarious cavitated defects due to abrasion, erosion, or abfraction. Class V lesions require restorations when tooth structure is soft or cavi- tated (as seen in Fig. Restorations should also be considered to protect noncarious defects (like abra- sion defects) that occur in this part of the tooth if the tooth is sensitive and does not respond to desensitizing agents, if the lesion is very deep and cannot be kept clean, or if it appears that it will continue to advance due to poor oral hygiene or parafunctional habits. Root caries (arrow) on an area of exposed consists of five walls: distal, occlusal, mesial, gingival, cementum after gingival recession. These preparations have eight line angles: axiomesial, axiogingival, axiodistal, axio-occlusal, of class V caries. Darker (radiolucent) areas of cervical mesiogingival, distogingival, mesio-occlusal, and disto- abrasion, as well as older types of radiolucent restor- occlusal. The axio-occlusal and axiogingival line angles ative materials, can appear like class V or root surface are prepared with retentive grooves labeled as A-O and caries on radiographs.
An enlarged cervical node could be the result of most other intraoral structures order 100mg silagra with mastercard, including all maxil- the lower lip infection purchase silagra 100 mg with amex. On the right side purchase 100 mg silagra with visa, lymph empties into the junc- located over the parotid gland in front of the ear, tion of the right subclavian and internal jugular veins. The parotid and submandibular nodes, as well as excess lymph resulting from a sore • Describe the pathway by which an infection throat (inflamed tonsils and pharynx), drain into the (or cancer cells) might spread from a maxillary deep and superficial cervical chain of nodes. These tooth to the neck through the lymph system, are located along the large sternocleidomastoid neck and then through the venous system. To cite an example of the spread of infec- • Describe the pathway by which an infection tion, if an infection like a pimple or aphthous ulcer might spread from a mandibular anterior tooth formed on the lower lip, it would drain into the mental to the neck through the lymph system and then nodes, which would in turn drain into the subman- through the venous system. Now that you have learned the location and shape of canals) will appear on the radiograph as darker struc- many bony structures within the head, it is possible to tures (called radiolucent). Finally, a panoramic radio- look at a radiograph and identify many of these struc- graph can be taken with a device that rotates around tures based on their shape and location. In order to do the jaws so that the operator can view structures from this, you need to know that the denser structures in the the right, front, and left on one film. It is as though head (especially the bones and teeth) will appear on the you could take the horseshoe-shaped mandible with its radiograph as the lightest (more white or radiopaque). Condylar process edge of the shape and location of structures in (Clue: It articulates within the concavity of the skull, study the radiograph in Figure 14-52 and the temporal bone called the mandibular see how many of the following structures you can [ articular] fossa). Sigmoid notch the following lettered items with the correspond- (Clue: This notch is between the coronoid and ing number and arrow on the radiograph. Note that each tooth has (Clue: It is a radiolucent canal with its mandib- one or more roots embedded into the bony ular foramen where the inferior alveolar nerve (opaque) alveolar processes. Mental foramen (almost invisible) periodontal ligaments around (Clue: It is a radiolucent circle near the ends each root? Note that each tooth has branch of the inferior alveolar nerve splits off one or more roots embedded into the bony and exits the mandible to innervate the lower (opaque) alveolar processes. Body of the mandible (Clue: It is the bump of bone behind the last maxillary molar. Note its proximity to the roots horizontal body of the mandible where it joins of the maxillary molars and premolars. Ramus of maxillae and palatine bones (Clue: It is the vertical part of the mandible. Coronoid process (Clue: It is the depression on the base of the (Clue: It is shaped like the point of a king’s cranium in the temporal bone where the con- crown. Test your ability to identify these structure based on their shape and relative location by matching the letter of a description (A–S) with the number of each structure (1–19). Articular eminence (Clue: The septum separates the right and left (Clue: It is the opaque bump of temporal bone halves of the nasal passageways. Hyoid bone the condyles and the mandible downward (Clue: This bone appears to float below the [opening the mouth] as it moves forward. Articular disc space cles attached to it are radiolucent and are not (Clue: It is a radiolucency between the condyle visible. B—2 (there (Clue: This hollow radiolucent space is located are 14 maxillary teeth; two premolars are miss- superior to the maxillary anterior teeth. Permar’s oral embryology and microscopic anato- Blackwell Scientific Publications, 1981. Normal and abnormal findings in temporo- Oxford: Blackwell Scientific Publications, 1982. Keep in mind that soft tissue the mouth, recall the location of underlying bony land- structures cover the bones of the skull and are supplied marks, nerves, and vessels. Move your finger down toward the angle of the mandible to feel the insertion (labeled No. You can obtain (inferior border of the zygomatic bone and zygo- clues regarding possible health problems that have not matic process of the temporal bone) to feel the origin yet been diagnosed, and you can begin to predict how (labeled No. Notice • Medial pterygoid: Feel the bulge when your partner the posture, gait, breathing, and general well-being clenches while palpating the medial surface of the during your greeting. This may cause some tify swelling that could be a sign of pathology or infec- discomfort. The evaluator’s knowledge of pathology will be 8 Palpated helpful when distinguishing benign lesions from those 2 intraorally requiring follow-up pathology consult and/or biopsy. For this reason, it is important to be 7 Medial to inner angle able to locate and palpate these muscles where pos- of mandible sible. Sites for palpation of temporomandibular pate surrounding soft tissue to feel for unusual lumps joint and muscles of mastication (origin and insertion loca- or tenderness. Temporalis (anterior vertical fibers that close • Masseter: Feel the body of the masseter by palpat- mandible). Temporalis (posterior horizontal fibers that ing the bulge over the lateral surface of the mandible retract mandible). Lateral pterygoid near the angle while your partner clenches the jaws (palpated intraorally). Chapter 15 | Oral Examination: Normal Anatomy of the Oral Cavity 441 • Temporalis, anterior fibers: Palpate the origin of the mandible from side to side. Movement of the condyles anterior (vertical) fibers on the forehead just above a during minimal opening of the mandible cannot be line between the eyebrow and superior border of the felt as easily as when the mouth is opened wide since ear (labeled No. Since these muscle fibers help the condyles and mandible only rotate around a line close the mouth, see if you feel the bulge when your connecting the condyles (like a swing) during mini- partner clenches the teeth. Also, feel just above and posterior to the superior border of the condyles during lateral movement to see if you the ear (labeled No. Since these muscle fibers are discern differences in movement on the right side ver- involved in retruding the mandible, see if you can sus the left side during movement to the right, then feel a bulge when your partner retrudes (pulls back) movement to the left. This is likely due to the head of the condyle pterygoid can only be palpated intraorally. The anterior surface of the neck of the condyloid process is the location The neck should be evaluated for symmetry and to of part of the insertion of this muscle, but it cannot confirm that there are no lumps or bumps. This gland should be evalu- thin layer of tissue covering the eyeball and reflected ated visually and palpated (as in Fig. The pupil (dark center opening surrounded are located around the sternocleidomastoid muscles are by the colored iris) should not be severely pinpoint described next. Healthy nodes are normally not your partner and pressing your middle fingers over palpable, but infection or malignancies may cause them the skin just anterior to the external opening of the to become enlarged. A node that becomes palpable due ear and inferior to the zygomatic arch while your to an infection that drains into the node is more likely to partner opens wide and closes (Fig. In this case, look for the site ner opens and closes the mandible and moves the of infection based on your knowledge of the spread 442 Part 3 | Anatomic Structures of the Oral Cavity 1. Even after the infection is resolved, the nodes may remain enlarged but would be nontender and rub- bery in consistency. If a node becomes enlarged due to the effect of a malignancy, it is more likely to feel firm and nontender, but it also feels like it is attached to the underlying tissue, so it is relatively immovable, and it will continue to get larger. Nodes, when enlarged, can be felt by passing the sensitive fleshy part of the fingertips over the location of each node location.