The RespiratorySystem

The Upper and Lower Airway and AssociatedStructures2

Parotid Duct and Facial Injuries 22

Submandibular Gland: Calculus Formation 22

Sublingual Gland and Cyst Formation 22

The Pharynx 22

Killian’s Dehiscence and Foreign Bodies 22

The Piriform Fossa and Foreign Bodies 22

The Process of Swallowing (Deglutition) 22

Swallowing in Unconscious Individuals 22

Pharyngeal Obstruction of the Upper Airway 22

Loss of the Gag Reflex 22

Palatine Tonsils 23

Examination of the Tonsils 23

Tonsillitis 23

Quinsy 23

Adenoids 23

The Larynx 23

The Cricoid Cartilage and the Sellick Maneuver 23

Relationship between Vocal Folds and

Cricothyroid Ligament 23

Larynx in Children 23

Epiglottitis 23

Foreign Bodies in the Airway 23

Anatomic Rationale for Differences in Procedures for

Removing Foreign Bodies in Adults and Children 23

Lesions of the Laryngeal Nerves 24

Inspection of the Vocal Cords (Folds) with the

Laryngeal Mirror and Laryngoscope 25

Important Anatomic Axes for Endotracheal

Intubation 26

Anatomy of the Visualization of the Vocal Cords

with the Laryngoscope 27

Reflex Activity Secondary to Endotracheal

Intubation 28

The Trachea 28

Palpation of the Trachea 28

The Nose 17

Pupillodilatation 17

Examination of the Nasal Cavity 17

Infection of the Nasal Cavity 17

Nasal Obstruction 18

Trauma to the Nose 18

Nasal Fractures 18Skin Lacerations 18

Congenital Anomalies of the Nose 18

Median Nasal Furrow 18

Lateral Proboscis 18

The Paranasal Sinuses 18

Sinusitis and the Examination of the

Paranasal Sinuses 18

The Mouth 19

Examination of the Mouth 19

Lips and Vestibule and Facial Paralysis 20

Ranula 20

The Tongue 20

Laceration of the Tongue 20

Tongue and Airway Obstruction 20

Anatomy of Procedures 20Pulling the Tongue Forward in Airway

Obstruction 20Oral Endotracheal Intubation 20

Oral Endotracheal Intubation and theIncisor Teeth 20

Oral Endotracheal Intubation and theSmall Mandible 20

The Palate 20

Angioedema of the Uvula (Quincke’s Uvula) 20

Congenital Anomalies of the Palate 21

Cleft Palate 21

The Salivary Glands 21

Parotid Salivary Gland and Lesions of the

Facial Nerve 21

Parotid Gland Infections 21

Chapter Outline

Compromised Airway 28

Anatomy of Cricothyroidotomy 28Complications 29

Anatomy of Tracheostomy 29Complications 31

Some Important Airway Distances 31

Changes in the Tracheal Length with Respiration and Position of the Headand Neck 31

The Bronchi 32

Aspiration of Foreign Bodies and Stomach Contents 32

Suction Catheters, Endotracheal Tubes, and the

Bronchi 32

Bronchopulmonary Segments 32

Clinical Problem Solving Questions 32

Answers and Explanations 33

The Upper and Lower Airway and Associated Structures 17

THE NOSEPupillodilatationA vasoconstrictor sprayed into the nasal vestibule can ascendin the nasolacrimal duct to the conjunctival sac, where it isabsorbed, and may produce pupillodilatation.

Examination of the Nasal CavityExamination of the nasal cavity may be carried out by insert-ing a speculum through the external nares or by means of amirror in the pharynx. In the latter case, the choanae and theposterior border of the septum can be visualized (CD Fig. 2-1). It should be remembered that the nasal septum is rarelysituated in the midline. A severely deviated septum mayinterfere with drainage of the nose and the paranasal sinuses.

Infection of the Nasal CavityInfection of the nasal cavity can spread in a variety ofdirections. The paranasal sinuses are especially prone toinfection. Organisms may spread via the nasal part of thepharynx and the auditory tube to the middle ear. It is pos-sible for organisms to ascend to the meninges of the ante-rior cranial fossa, along the sheaths of the olfactory nervesthrough the cribriform plate, and produce meningitis.

Epistaxis, or bleeding from the nose, is a frequent con-dition. The most common cause is nose picking. Thebleeding may be arterial or venous, and most episodes oc-cur on the anteroinferior portion of the septum and in-volve the septal branches of the sphenopalatine and facialvessels.

Beware of bilateral cauterization of the septal mucousmembrane. It could compromise the blood supply to theperichondrium and cause necrosis of the cartilaginous partof the septum.

tubal elevation

soft palate

uvula

nasal septum superior concha

middle concha

inferior concha

B

A B

CD Figure 2-1 A. Position of the mirror in posterior rhinoscopy. B. Structures seen inposterior rhinoscopy.

lip, or across the lower eyelid, since future scars tend to con-tract and distort the depression.

CONGENITALANOMALIES OFTHE NOSE

Median Nasal FurrowIn median nasal furrow, the nasal septum is split, separatingthe two halves of the nose (CD Fig. 2-2A).

Lateral ProboscisIn lateral proboscis, a skin-covered process develops, usuallywith a dimple at its lower end (CD Fig. 2-2B).

THE PARANASALSINUSES

Sinusitis and the Examination ofthe Paranasal SinusesInfection of the paranasal sinuses is a common complicationof nasal infections. Rarely, the cause of maxillary sinusitis is

Nasal ObstructionNasal obstruction can be caused by edema of the mucousmembrane secondary to infection, or by foreign bodieslodged between the conchae. The shelf-like conchae makeimpaction and retention of balloons, peas, and small toysrelatively easy in children. Other causes include tumors,polyps, and septal abscesses.

Deflection of the nasal septum is common. It is be-lieved to occur most commonly in males because of traumain childhood.

The most voluminous part of the nasal cavity is close tothe floor, and it is usually possible to pass a well-lubricatedtube through the nostril along the inferior meatus into thenasopharynx.

Trauma to the NoseNasal Fractures

Fractures involving the nasal bones are common. Blows di-rected from the front may cause one or both nasal bones tobe displaced downward and inward.

Lateral fractures also occur in which one nasal bone isdriven inward and the other outward; the nasal septum isusually involved.

Skin Lacerations

Lacerations are sutured in the usual way. Remember, how-ever, that there is very little excess of skin so that the vascu-larity may be compromised if too much tension is placed onthe sutures. Avoid making incisions across depressed areason the side of the nose or at the junction of the nose and the

18 Chapter 2

CD Figure 2-2 A. Median nasal furrow in which the nasal septum has completely split,separating the two halves of the nose. Note that the external nares are separated by a widefurrow. (Courtesy of L Thompson.) B. Lateral proboscis.

A B

extension from an apical dental abscess. The extreme thin-ness of the medial wall of the orbit relative to the ethmoidalair cells must be emphasized. Ethmoidal sinusitis is the mostcommon cause of orbital cellulitis. The infection can easilyspread through the paper-thin bone.

The frontal, ethmoidal, and maxillary sinuses can bepalpated clinically for areas of tenderness (CD Fig. 2-3).The frontal sinus can be examined by pressing the finger up-ward beneath the medial end of the superior orbital margin.Here the floor of the frontal sinus is closest to the surface.

The ethmoidal sinuses can be palpated by pressing thefinger medially against the medial wall of the orbit. Themaxillary sinus can be examined for tenderness by pressingthe finger against the anterior wall of the maxilla below theinferior orbital margin; pressure over the infraorbital nervemay reveal increased sensitivity.

The frontal sinus is supplied by the supraorbital nerve,which also supplies the skin of the forehead and scalp. It isnot surprising, therefore, that patients with frontal sinusitis

have pain referred over this area (see CD Fig. 2-3). Themaxillary sinus is innervated by the infraorbital nerve and,in this case, pain is referred to the upper jaw, including theteeth (see CD Fig. 2-3).

THE MOUTHExamination of the MouthThe mouth is one of the most important areas of the bodythat the medical professional is called on to examine. Need-less to say, the health professional must be able to recognizeall the structures visible in the mouth and be familiar withthe normal variations in the color of the mucous membranecovering the underlying structures. The sensory nerve sup-ply and lymph drainage of the mouth cavity should beknown. The close relation of the lingual nerve to the lower

The Upper and Lower Airway and Associated Structures 19

frontal sinus

maxillary sinus

sphenoethmoidal recess

superior meatus

middle meatus

bulla ethmoidalishiatus semilunaris

inferior meatus

nasal septum palate

inferior concha

maxillary sinus

middle concha

ethmoidal sinuses

frontal sinus

superior concha

A B

C

CD Figure 2-3 A. Bones of the face showing the po-sitions of the frontal and maxillary sinuses. B. Regionswhere pain is experienced in sinusitis (lightly dottedarea in frontal sinusitis; solid area in sphenoethmoidalsinusitis; and heavily dotted area in maxillary sinusi-tis). C. Coronal section through the nasal cavity show-ing the frontal, ethmoidal, and maxillary sinuses.

Sometimes this is inadequate to relieve the obstruction andshould be supplemented by placing the fingers behind theangles of the mandible and exerting forward pressure. Thismoves the mandible forward, causing displacement of thetongue away from the laryngeal opening, since the mandibleis attached to the tongue by the genioglossus muscles.

Oral Endotracheal Intubation

Total visualization of the glottis with a laryngoscope is notnecessary for endotracheal intubation. If the epiglottis is vis-ible, the tube is laid on the laryngeal side of the epiglottisand advanced along its surface. Often this procedure alonewill allow the tube to go into the trachea. If only the esoph-agus is visible and not the vocal cords, the endotracheal tubecan be placed “blindly” just anterior to the esophageal open-ing. Occasionally when the tube is caught at the anteriorglottic constriction, the head should be flexed slightly, al-lowing the pressure of the tongue to displace the endotra-cheal tube posteriorly and hence move it into the openingof the glottis. Frequently this maneuver has to be supple-mented by turning the head slightly to one side or another.The use of styleted endotracheal tubes also may help in thissituation. “Trigger tubes” may be used, which allow the tipto be manipulated from above.

When oral endotracheal intubation is impossible in theabove situations, nasotracheal intubation may be successful,since the tube approaches the glottis slightly more posteri-orly and is directed more toward it.

Oral Endotracheal Intubation and the Incisor Teeth

Interference with endotracheal intubation may be causedby the presence of protruding incisor teeth, often making itnecessary to put the endotracheal tube in an extreme lateralposition to approach the glottis.

Oral Endotracheal Intubation and the Small Mandible

Patients with receding jaws, secondary to a small mandible,often make intubation difficult, and in some cases the nasalroute or a lighted stylet or digital intubation must be used.However, since this anatomic configuration approaches thepicture seen in younger children, many times a smallstraight blade such as a Miller no. 2 or Miller no. 3 can over-come the visual difficulties noted when a curved blade ofthe Macintosh type is used.

THE PALATEAngioedema of the Uvula (Quincke’sUvula)The uvula has a core of voluntary muscle, the musculusuvulae, that is attached to the posterior border of the hard

third molar tooth should be remembered. The close rela-tion of the submandibular duct to the floor of the mouthmay enable one to palpate a calculus in cases of periodicswelling of the submandibular salivary gland.

Lips and Vestibule and FacialParalysisAsymmetry of the lips and paralysis of the buccinator with atendency to accumulate saliva and food in the vestibule in-dicate a lesion of the facial nerve on that side.

RanulaRanula is a cystic swelling arising in a distended mucousgland of the mucous membrane. It commonly occurs in thefloor of the mouth, and because of its transparent covering,it resembles frog skin.

THE TONGUELaceration of the TongueA wound of the tongue is often caused by the patient’s teethfollowing a blow on the chin when the tongue is partly pro-truded from the mouth. It can also occur when a patient ac-cidentally bites the tongue while eating, during recoveryfrom an anesthetic, or during an epileptic attack. Bleedingis halted by grasping the tongue between the finger andthumb posterior to the laceration, thus occluding thebranches of the lingual artery.

Tongue and Airway ObstructionIn an unconscious patient, there is a tendency for thetongue to fall backward and obstruct the laryngeal opening.This is caused by the loss of tone of the extrinsic musclesand, unless quickly corrected “with a jaw thrust or chin liftmaneuver,” will lead to all of the signs and symptoms of air-way obstruction.

Anatomy of Procedures

Pulling the Tongue Forward in AirwayObstruction

The head should be extended at the atlantooccipital jointand the neck flexed at the C4 to C7 joints. The extendedhead stretches the fascia and muscles of the front of the neckand causes a forward and downward movement of themandible that is correctable by placing a finger below thesymphysis menti and pulling the mandible forward and up.

20 Chapter 2

palate. Surrounding the muscle is the loose connective tis-sue of the submucosa that is responsible for the greatswelling of this structure secondary to angioedema.

CONGENITALANOMALIES OFTHE PALATE

Cleft PalateCleft palate is commonly associated with cleft upper lip.All degrees of cleft palate occur and are caused by failureof the palatal processes of the maxilla to fuse with eachother in the midline; in severe cases, these processes alsofail to fuse with the primary palate (premaxilla) (CD Figs.2-4 and 2-5). The first degree of severity is cleft uvula, andthe second degree is ununited palatal processes. The thirddegree is ununited palatal processes and a cleft on one sideof the primary palate. This type is usually associated withunilateral cleft lip. The fourth degree of severity, which israre, consists of ununited palatal processes and a cleft onboth sides of the primary palate. This type is usually asso-ciated with bilateral cleft lip. A rare form may occur inwhich a bilateral cleft lip and failure of the primary palateto fuse with the palatal processes of the maxilla on eachside are present.

A baby born with a severe cleft palate presents a difficultfeeding problem, since he or she is unable to suck effi-ciently. Such a baby often receives in the mouth some milk,which then is regurgitated through the nose or aspirated intothe lungs, leading to respiratory infection. For this reason,careful artificial feeding is required until the baby is strongenough to undergo surgery. Plastic surgery is recommendedusually between 1 and 2 years of age, before improperspeech habits have been acquired.

THE SALIVARYGLANDS

Parotid Salivary Gland and Lesionsof the Facial NerveThe facial nerve lies in the interval between the superficialand deep parts of the gland. A benign parotid tumor rarely,if ever, causes facial palsy. A malignant tumor of the parotidis usually highly invasive and quickly involves the facialnerve, causing unilateral facial paralysis.

Parotid Gland InfectionsThe parotid gland may become acutely inflamed as a resultof retrograde bacterial infection from the mouth via theparotid duct. The gland may also become infected via thebloodstream, as in mumps.

The Upper and Lower Airway and Associated Structures 21

CD Figure 2-4 Cleft hard and soft palate.

A B

C D

E

CD Figure 2-5 Different forms of cleft palate: cleft uvula (A),cleft soft and hard palate (B), total unilateral cleft palate andcleft lip (C), total bilateral cleft palate and cleft lip (D), andbilateral cleft lip and jaw (E).

THE PROCESS OFSWALLOWING(DEGLUTITION)

Swallowing in UnconsciousIndividualsDuring swallowing in conscious individuals, food andfluid cross naturally from the mouth to the esophagus,and movements of air from the nose to the larynx ismomentarily stopped. In unconscious individuals, whenthe reflex mechanisms are not functioning, it is possiblefor food and fluid to enter the bronchial tree or air to enterthe stomach. Moreover, should vomiting occur, the regur-gitated gastric contents may be inhaled into the lungs(see below).

Pharyngeal Obstruction of theUpper AirwayThis condition frequently occurs in patients duringcardiopulmonary arrest or in the decreased level of con-sciousness that accompanies a major cerebrovascular acci-dent or drug overdose. The obstruction is caused when theatonic tongue falls back and the pharyngeal wall caves indue to loss of tone of the pharyngeal muscles. The obstruc-tion may clear if the patient is placed in the lateral decubi-tus position, with the neck extended and the jaw pulledforward (which pulls the tongue forward). If the patientmust lie in a supine position, an oropharyngeal or nasopha-ryngeal airway may have to be inserted to counteract theflaccid pharyngeal walls.

Loss of the Gag ReflexIn conscious patients the airway is protected by a number ofimportant reflexes, including the gag reflex, the laryngealreflex, and the cough reflex. The gag or swallowing reflexoccurs in response to stimulation of the pharyngeal mucousmembrane, which is innervated by the glossopharyngealnerve. The laryngeal and cough reflexes (trachea andbronchi) are mediated by the vagus nerve. These protectivereflexes are lost in descending order as the patient becomesless and less responsive. In these circumstances the airwaymay be blocked by aspiration of vomit and gastric and pha-ryngeal secretions.

Parotid Duct and Facial InjuriesThe parotid duct, which is a comparatively superficial struc-ture on the face, runs forward from the parotid gland onefingerbreadth below the zygomatic arch (see text Fig. 2-18).It is about 2 in. (5 cm) long and can be rolled beneath theexamining finger at the anterior border of the masseter as itturns medially and pierces the buccinator muscle; it thenopens into the mouth opposite the upper second molartooth (see text Fig. 2-8).

The parotid duct may be damaged in injuries to theface or may be inadvertently cut during surgical operationson the face. The integrity of the parotid duct can be estab-lished by wiping the inside of the cheek dry and then press-ing on the parotid gland. Look for a drop of viscid saliva toappear on the tip of the papilla in the mouth.

Submandibular Gland: CalculusFormationThe submandibular salivary gland is a common site of cal-culus formation. The presence of a tense swelling below thebody of the mandible, which is greatest before or during ameal and is reduced in size or absent between meals, is di-agnostic of the condition. Examination of the floor of themouth will reveal absence of ejection of saliva from the ori-fice of the duct of the affected gland. Frequently, the stonecan be palpated in the duct, which lies below the mucousmembrane of the floor of the mouth.

Sublingual Gland and CystFormationBlockage of one of the ducts of the sublingual gland maycause cysts under the tongue.

THE PHARYNXThe Killian’s Dehiscence and Foreign BodiesInverted foreign bodies tend to get snared in the region ofKillian’s dehiscence.

The Piriform Fossa and ForeignBodiesThe piriform fossa is a common site for fish bones or otherforeign bodies to become lodged.

22 Chapter 2

PALATINE TONSILSExamination of the TonsilsWith the mouth wide open and with a good light shining intothe mouth, the tongue is depressed with a spatula. The ton-sils can be clearly seen on each side of the oral pharynx in thedepression between the palatoglossal and palatopharyngealfolds. Note the size and color of the tonsil; a reddened tonsilcovered with mucus or pus is a clear indication of tonsillitis.

TonsillitisThe palatine tonsils reach their maximum normal size inearly childhood. After puberty, together with other lym-phoid tissues in the body, they gradually atrophy. The pala-tine tonsils are a common site of infection, producing thecharacteristic sore throat and pyrexia. The deep cervicallymph node situated below and behind the angle of themandible, which drains lymph from this organ, is usuallyenlarged and tender.

Tonsillectomy, which is often the treatment for recur-rent episodes of tonsillitis, is sometimes accompanied bytroublesome postoperative bleeding from the external pala-tine vein.

QuinsyA peritonsillar abscess, or quinsy, is caused by spread of in-fection from the palatine tonsil to the loose connective tis-sue outside the capsule (see text Fig. 2-24).

AdenoidsAdenoids are enlarged nasopharyngeal tonsils usually associ-ated with infection. Excessive enlargement blocks the poste-rior nasal openings and causes the patient to snore loudly atnight and to breathe through the open mouth. The close re-lationship of the infected lymphoid tissue to the auditorytube may be the cause of deafness and recurrent otitis media.

THE LARYNXThe Cricoid Cartilage and theSellick ManeuverThe continuous ring structure of the cricoid cartilage is uti-lized when applying pressure on the cricoid to control re-gurgitation of stomach contents during the induction ofanesthesia.

Relationship between Vocal Foldsand Cricothyroid LigamentText Fig. 2-27 shows the relationship between the vocal foldsand the cricothyroid ligament. It is clear that the folds maybe damaged in puncture wounds in the front of the larynx.

Larynx in ChildrenIn children the neck is shorter and the larynx is more cepha-lad than in adults (CD Fig. 2-6). At birth the cricoid cartilagelies at the level of the fourth cervical vertebra, and only at theage of 6 years does it lie opposite the sixth cervical vertebra.The glottis at birth lies opposite the second cervical vertebra.

The epiglottis is U-shaped and less flexible in children,which sometimes makes it difficult to line up the oral, pha-ryngeal, and tracheal axes when passing a laryngoscope.

The rima glottidis tends to be more anterior in childrenthan in adults. The vocal folds in children have thicker sub-mucosa, so that edema of the folds is more likely to occludethe glottis.

As mentioned previously, the cavity of the larynx is nar-rowest within the cricoid ring in children, whereas the glot-tis is the narrowest part of the cavity in adults.

EpiglottitisAn acute inflammatory swelling of the mucous membrane ofthe epiglottis can compromise the upper airway. The inflam-mation may spread rapidly in the loosely arranged submucosadown to the vocal cords. Here the spreading stops because themucosa is tightly adherent to the underlying vocal ligaments.The condition is most often seen in children where the nar-row passageway quickly leads to upper airway obstruction.

Foreign Bodies in the AirwayThe laryngeal and cough reflexes mediated through the va-gus nerves are the natural defense mechanisms for expellingforeign bodies from the airway at all ages. If coughing is suc-cessfully freeing the obstruction, it should be encouraged tocontinue. If intervention is necessary, anatomic and physio-logic age differences dictate treatment.

Anatomic Rationale forDifferences in Procedures forRemoving Foreign Bodies inAdults and ChildrenIt is generally agreed that all maneuvers are directed towardthe increase in intrathoracic pressure by compressing the

The Upper and Lower Airway and Associated Structures 23

may be involved in a bronchial or esophageal carcinoma orin secondary metastatic deposits in the mediastinal lymphnodes. The right and left recurrent laryngeal nerves may bedamaged by malignant involvement of the deep cervicallymph nodes.

Section of the external laryngeal nerve produces weak-ness of the voice because the vocal fold cannot be tensed.The cricothyroid muscle is paralyzed (CD Fig. 2-7).

Unilateral complete section of the recurrent laryn-geal nerve results in the vocal fold on the affected sideassuming the position midway between abduction andadduction. It lies just lateral to the midline. Speech is notgreatly affected because the other vocal fold compensates tosome extent and moves toward the affected vocal fold (CDFig. 2-7).

Bilateral complete section of the recurrent laryngealnerve results in both vocal folds assuming the positionmidway between abduction and adduction. Breathing isimpaired because the rima glottidis is partially closed, andspeech is lost (CD Fig. 2-7).

Unilateral partial section of the recurrent laryngealnerve results in a greater degree of paralysis of the abductormuscles than of the adductor muscles. The affected vocalfold assumes the adducted midline position (CD Fig. 2-7).This phenomenon has not been explained satisfactorily.It must be assumed that the abductor muscles receive a

intrathoracic gas volume to expel the foreign body fromthe airway. For children older than 1 year and for adults,the abdominal thrust (Heimlich maneuver) should be used.The rapid compression of the abdominal viscera suddenlyforces the diaphragm into the thoracic cavity. In infants, therelatively large size of the liver and the delicate structure ofthe abdominal viscera generally preclude its use. Childrenyounger than 1 year should be placed face down over therescuer’s arm, with the head lower than the trunk, and mea-sured back blows should be delivered between the scapulae.If this fails to open the airway, they should be rolled over,and four rapid sternal compressions should be administered.

It is now accepted that sudden blows to the back in theolder age groups, especially in the standing or sittingposition, extends the thoracic part of the vertebral columnand may displace the foreign body further down the airway,leading to impaction or complete obstruction.

Lesions of the Laryngeal NervesThe muscles of the larynx are innervated by the recurrent la-ryngeal nerves, with the exception of the cricothyroid mus-cle, which is supplied by the external laryngeal nerve. Boththese nerves are vulnerable during operations on the thyroidgland because of the close relationship between them andthe arteries of the gland. The left recurrent laryngeal nerve

24 Chapter 2

mandiblebody of

hyoid bone

thyroid cartilage

cricoid cartilage

mandible

hyoid cartilagethyroid cartilage

cricoid cartilagemanubrium sterni

CD Figure 2-6 Sagittal sections of the neck of an adult (A) and an infant (B) shortly afterbirth. Different vertebral levels in these age groups are shown.

greater number of nerves than the adductor muscles, andthus partial damage of the recurrent laryngeal nerve resultsin damage to relatively more nerve fibers to the abductormuscles. Another possibility is that the nerve fibers to the ab-ductor muscles are traveling in a more exposed position inthe recurrent laryngeal nerve and are therefore more proneto be damaged.

Bilateral partial section of the recurrent laryngealnerve results in bilateral paralysis of the abductor musclesand the drawing together of the vocal folds (CD Fig. 2-7).Acute breathlessness (dyspnea) and stridor follow, andcricothyroidotomy or tracheostomy is necessary.

Inspection of the Vocal Cords(Folds) with the Laryngeal Mirrorand LaryngoscopeThe interior of the larynx can be inspected indirectlythrough a laryngeal mirror passed through the open mouthinto the oral pharynx (CD Fig. 2-8). A more satisfactorymethod is the direct method using the laryngoscope. Theneck is brought forward on a pillow and the head is fullyextended at the atlantooccipital joints. The illuminated

The Upper and Lower Airway and Associated Structures 25

rimaglottidis

epiglottisright vocal fold (cord)

aryepiglottic fold

corniculate cartilage

inspiration

phonation

inspiration

inspiration

inspiration

inspiration

A. Bilateral external laryngeal nerve palsy

B. Unilateral complete section of right recurrent laryngeal nerve

C. Bilateral complete section of recurrent laryngeal nerves

D. Unilateral partial section of right recurrent laryngeal nerve

E. Bilateral partial section of recurrent laryngeal nerves

CD Figure 2-7 The position of thevocal folds (cords) after damage tothe external and recurrent laryngealnerves.

If the patient is asked to breathe deeply, the vocal foldsbecome widely abducted, and the inside of the trachea canbe seen.

Important Anatomic Axes forEndotracheal IntubationThe upper airway has three axes that have to be brought intoalignment if the glottis is to be viewed adequately through alaryngoscope—the axis of the mouth, the axis of the phar-ynx, and the axis of the trachea (CD Fig. 2-9).

instrument can then be introduced into the larynx over theback of the tongue (CD Fig. 2-8). The valleculae, the piri-form fossae, the epiglottis, and the aryepiglottic folds areclearly seen. The two elevations produced by the corniculateand cuneiform cartilages can be recognized. Within the lar-ynx, the vestibular folds and the vocal folds can be seen. Theformer are fixed, widely separated, and reddish in color; thelatter move with respiration and are white in color. Withquiet breathing, the rima glottidis is triangular, with the apexin front. With deep inspiration, the rima glottidis assumes adiamond shape because of the lateral rotation of the ary-tenoid cartilages.

26 Chapter 2

B

hard palate

tongue

entrance into larynx

laryngoscope

examiner'seye

examiner'seye

tongueentranceinto larynx

vestibular fold

rima glottidis

cuneiformcartilage

corniculatecartilage

epiglottisvocal fold(cord)

orientation oflaryngeal inlet

A

CD Figure 2-8 Inspection of the vocal folds (cords) indirectly through a laryngeal mirror(A) and through a laryngoscope (B). Note the orientation of the structures forming thelaryngeal inlet.

The following procedures are necessary: First the headis extended at the atlantooccipital joints. This brings the axisof the mouth into the correct position. Then the neck isflexed at cervical vertebrae C4 to C7 by elevating the backof the head off the table, often with the help of a pillow. Thisbrings the axes of the pharynx and the trachea in line withthe axis of the mouth.

Anatomy of the Visualization of theVocal Cords with the Laryngoscope

1. The pear-shaped epiglottis is attached by its stalk at itslower end to the interior of the thyroid cartilage (see textFig. 2-26).

2. The vocal cords (ligaments) are attached at their ante-rior ends to the thyroid cartilage just below the attach-ment of the epiglottis (see text Fig. 2-26).

3. Because of the above two facts, it follows that manipu-lation of the epiglottis and possibly the thyroid cartilagewill greatly assist the operator in visualizing the cordsand the glottis.

The patient’s head and neck are correctly positioned sothat the three axes of the airway (noted above) have been es-tablished and the patient has assumed the “sniffing” posi-tion. The laryngoscope is inserted into the patient’s mouth,and the blade is correctly placed alongside the rightmandibular molar teeth. The blade can then be passed overthe tongue and down into the esophagus. The tip of the

The Upper and Lower Airway and Associated Structures 27

A

B

M

T

P

M

T

P

CD Figure 2-9 Anatomic axes for endo-tracheal intubation. A. With the head inthe neutral position, the axis of the mouth(M), the axis of the trachea (T), and theaxis of the pharynx (P) are not alignedwith one another. B. If the head is ex-tended at the atlantooccipital joints, theaxis of the mouth is correctly placed. Ifthe back of the head is raised off the tablewith a pillow, thus flexing the cervicalvertebral column, the axes of the tracheaand pharynx are brought in line with theaxis of the mouth.

changes are largely mediated through the branches of thevagus nerves.

THE TRACHEAPalpation of the TracheaThe trachea can be readily felt below the larynx. As itdescends, it becomes deeply placed and may lie as much as1.5 in. (4 cm) from the surface at the suprasternal notch.Remember that in the adult it may measure as much as 1 in.(2.5 cm) in diameter, but in a 3-year-old child it maymeasure only 0.5 in. in diameter. The trachea is a mobileelastic tube and is easily displaced by the enlargement ofadjacent organs or the presence of tumors. Remember alsothat lateral displacement of the cervical part of the tracheamay be caused by a pathologic lesion in the thorax.

Compromised AirwayIn a medical emergency immediate treatment is necessary.

Anatomy of Cricothyroidotomy

In cricothyroidotomy, a tube is inserted in the interval be-tween the cricoid cartilage and the thyroid cartilage. Thetrachea and larynx are steadied by extending the neck over asandbag.

A vertical or transverse incision is made in the skin inthe interval between the cartilages (CD Fig. 2-11). Theincision is made through the following structures: the skin,the superficial fascia (beware of the anterior jugular veins,which lie close together on either side of the midline), the

blade must be fully inserted into the esophagus (so that youknow where it is anatomically). The blade should by nowhave moved toward the midline and followed the anatomiccurvature on the posterior surface of the tongue.

The laryngoscopic blade is then gently and slowly with-drawn. The tip of the blade is kept under direct vision at alltimes and is permitted to rise up out of the esophagus. Re-member that the tip of the blade is at first in the esophagusand therefore distal to the level of the vocal cords. Once theblade tip has left the esophagus, it is in the laryngeal part ofthe pharynx, and a view of the glottis should immediately beapparent (CD Fig. 2-10). This is the critical stage. If the glot-tis is not visualized, then the operator is viewing the poste-rior surface of the epiglottis. Now use your anatomicknowledge.

With the tip of the blade of the laryngoscope applied tothe posterior surface of the epiglottis, gently lift up andelevate the epiglottis to expose the glottis. If the glottis is stillnot in view, do not panic! Again use your knowledge ofanatomy. With the right free hand grasp the thyroid carti-lage (to which the cords and the epiglottis are attached) be-tween your finger and thumb and apply firm backward,upward, rightward pressure (BURP). This maneuver re-aligns the box of the larynx relative to the laryngoscopicblade, and the visual axis of the operator and the glottisshould immediately be seen.

Reflex Activity Secondary toEndotracheal IntubationStimulation of the mucous membrane of the upper airwayduring the process of intubation may produce cardiovascu-lar changes such as bradycardia and hypertension. These

28 Chapter 2

tongue

vallecula

tubercle ofepiglottis

aryepiglottic fold

piriform fossa

cuneiform cartilage

corniculate cartilage

rima glottidis

vocal fold

glossoepi-glottic fold

lateralvestibular fold

epiglottisglottic foldglossoepi-

median

CD Figure 2-10 The laryngeal inlet as seenfrom above.

investing layer of deep cervical fascia, the pretracheal fascia(separate the sternohyoid muscles and incise the fascia), andthe larynx. The larynx is incised through a horizontal inci-sion through the cricothyroid ligament and the tube in-serted (CD Fig. 2-12).

Complications

1. Esophageal perforation: Because the lower end of thepharynx and the beginning of the esophagus lie directlybehind the cricoid cartilage, it is imperative that thescalpel incision through the cricothyroid membranenot be carried too far posteriorly. This is particularly im-portant in young children, in whom the cross diameterof the larynx is so small.

2. Hemorrhage: The small branches of the superiorthyroid artery that occasionally cross the front of thecricothyroid membrane to anastomose with one an-other should be avoided.

Anatomy of Tracheostomy

Tracheostomy is rarely performed and is limited to patientswith extensive laryngeal damage and infants with severe air-way obstruction. Because of the presence of major vascularstructures (carotid arteries and internal jugular vein), thethyroid gland, nerves (recurrent laryngeal branch of vagusand vagus nerve), the pleural cavities, and esophagus, metic-ulous attention to anatomic detail has to be observed (CDFig. 2-13).

The Upper and Lower Airway and Associated Structures 29

thyrohyoidmembrane(ligament)

sternohyoidmuscle

superior belly ofomohyoid muscle

cricothyroid membrane(ligament)

cricothyroidmuscle

anterior jugularvein isthmus

of thyroidgland

first tracheal ring

cricoidcartilage

site of skinincision

thyroid cartilage

body of hyoidbone

fascia

thyroid cartilage

smallcricothyroid

artery

skinedge

cricothyroidmembrane(ligament)

cricoidcartilage

cricothyroidmembrane(ligament)

thyroidcartilage

A

B C

CD Figure 2-11 The anatomy of cricothyroidotomy. A. A vertical incision is made throughthe skin and superficial and deep cervical fasciae. B. The cricothyroid membrane (ligament)is incised through a horizontal incision close to the upper border of the cricoid cartilage.C. Insertion of the tube.

30 Chapter 2

right and leftarytenoidcartilages

epiglottis

body of hyoid bone

right and left vocalligaments (cords)

thyroid cartilage

cricothyroid membraneor ligament

tube

cricoid cartilage

first tracheal ring

CD Figure 2-12 View of the interior ofthe larynx as seen from the right side (theright lamina of the thyroid cartilage hasbeen removed). Note the closeness of thedeep end of the cricothyroidotomy tube tothe vocal cords, especially if the tube isdirected upward.

pretracheallayer of deep

cervical fascia

omohyoid muscle

sternothyroid muscle

sternocleidomastoid muscle

investing layer ofdeep cervical fascia

platysma muscle

sternohyoidmuscle

isthmusof thyroidgland

anterior jugular vein

branch of superiorthyroid artery

thyroid gland

commoncarotidartery

internaljugularvein

deep cervicallymph node

vagus nervesympathetictrunkesophagus

prevertebrallayer ofdeep cervicalfasciacarotid sheath

C7

skin

CD Figure 2-13 Cross section of the neck at the level of the second tracheal ring. A verticalincision is made through the ring, and the tracheostomy tube is inserted.

The procedure is as follows:

1. The thyroid and cricoid cartilages are identified and theneck is extended to bring the tracheal forward.

2. A vertical midline skin incision is made from the regionof the cricothyroid membrane inferiorly toward thesuprasternal notch.

3. The incision is carried through the superficial fasciaand the fibers of the platysma muscle. The anteriorjugular veins in the superficial fascia are avoided bymaintaining a midline position.

4. The investing layer of deep cervical fascia is incised.

5. The pretracheal muscles embedded in the pretrachealfascia are split in the midline two fingerbreadths supe-rior to the sternal notch.

6. The tracheal rings are then palpable in the midline, orthe isthmus of the thyroid gland is visible. If a hook isplaced under the lower border of the cricoid cartilageand traction is applied upward, the slack is taken out ofthe elastic trachea; this stops it from slipping from sideto side.

7. A decision is then made as to whether to enter the tra-chea through the second ring above the isthmus of thethyroid gland; through the third, fourth, or fifth ring byfirst dividing the vascular isthmus of the thyroid gland;or through the lower tracheal rings below the thyroidisthmus. At the latter site, the trachea is receding fromthe surface of the neck, and the pretracheal fasciacontains the inferior thyroid veins and possibly thethryoidea ima artery.

8. The preferred site is through the second ring of the tra-chea in the midline, with the thyroid isthmus retractedinferiorly. A vertical tracheal incision is made, and thetracheostomy tube is inserted.

Complications

Most complications result from not adequately palpatingand recognizing the thyroid, cricoid, and tracheal cartilagesand not confining the incision strictly to the midline.

1. Hemorrhage: The anterior jugular veins located in thesuperficial fascia close to the midline should beavoided. If the isthmus of the thyroid gland is tran-sected, secure the anastomosing branches of the supe-rior and inferior thyroid arteries that cross the midlineon the isthmus.

2. Nerve paralysis: The recurrent laryngeal nerves may bedamaged as they ascend the neck in the groove betweenthe trachea and the esophagus.

3. Pneumothorax: The cervical dome of the pleura maybe pierced. This is especially common in children be-cause of the high level of the pleura in the neck.

4. Esophageal injury: Damage to the esophagus, which islocated immediately posterior to the trachea, occursmost commonly in infants; it follows penetration of thesmall-diameter trachea by the point of the scalpel blade.

SOME IMPORTANTAIRWAY DISTANCES

CD Table 2-1 shows some important distances betweenthe incisor teeth or nostrils to anatomic landmarks inthe airway in the adult. These approximate figures arehelpful in determining the correct placement of an endo-tracheal tube.

CHANGES IN THETRACHEAL LENGTHWITH RESPIRATIONAND POSITION OFTHE HEAD ANDNECK

On deep inspiration the carina may descend by as much as3 cm. Extension of the head and neck, as when maintainingan airway in an anesthetized patient, may stretch the tracheaand increase its length by 25%.

The Upper and Lower Airway and Associated Structures 31

Important AirwayDistances (Adult)a

aAverage figures given � 1–2 cm.

CD Table 2-1

DistancesAirway (approximate)

Incisor teeth to the vocal cords 5.9 in. (15 cm)Incisor teeth to the carina 7.9 in. (20 cm)External nares to the carina 11.8 in. (30 cm)

Suction Catheters, EndotrachealTubes, and the BronchiSuction catheters and endotracheal tubes are more likely toenter the right more vertical principal bronchus than theobliquely positioned left principal bronchus in adults andolder children.

BRONCHOPULMO-NARY SEGMENTS

See CD-ROM Chapter 3.

THE BRONCHIAspiration of Foreign Bodies andStomach ContentsIn adults, foreign bodies and stomach contents tend to beaspirated into the right principal bronchus, since this ismore in line with the trachea than the left bronchus.In young babies, since both bronchi arise from the tracheaat equal angles, no predilection for the right bronchusexists.

32 Chapter 2

Clinical Problem Solving QuestionsRead the following case histories/questions and give

the best answer for each.

1. A 36-year-old man was taken to the emergency depart-ment after having been found lying unresponsive in alocal park with an empty whisky bottle nearby. He wasgiven oxygen by an open face mask during the 15-minute ride in the ambulance. The paramedic decidedto improve the airway by passing a soft nasal tube. Onattempting to pass the well-lubricated tube into thepatient’s nose, the paramedic found it impossible topush it much beyond the nasal vestibule on either side.What are the common anatomic causes of obstructionof the nasal airway?

2. A 12-year-old girl was brought to the hospital with a his-tory of fever, malaise, anorexia, and a sore throat. Shealso had hoarseness, a cough, and rhinitis. On exami-nation there was erythema of the posterior pharyngealwall, with small ulcers on the palatoglossal folds andsoft palate. The tonsils were seen to be red and en-larged, and an obvious white-yellow exudate was seenon the surface of the left tonsil. Examination of thedeep cervical lymph nodes showed enlargement andtenderness of the node below and behind the angle ofthe mandible; the enlargement was greatest on the leftside. A diagnosis of viral pharyngitis was made. List thevarious lymphoid organs found in the nasal and oralparts of the pharynx. Explain Waldeyer’s ring.

3. A 3-year-old boy was playing with his toys on the floorwhen his sister decided to share some peanuts withhim. A few minutes later he started to cough and gave

a hoarse cry. The cough then became croupy, andaphonia occurred. The mother, hearing the commo-tion, rushed into the room and quickly realized whathad happened. She turned the child upside down andhit his back several times, but with no effect. The child,now in obvious respiratory distress, was rushed to thelocal emergency department. On examination, he wastachypneic, with suprasternal retractions. He was notcoughing, and although he attempted to cry, there wasno sound. He would not tolerate being laid down. Onthe basis of your knowledge of the anatomy of the air-way, where do you think the foreign body was lodged?Describe the normal protective reflexes that exist in theairway to prevent the inhalation of a foreign body. Whatis the anatomic and physiologic rationale behind theuse of back blows, chest thrusts, and abdominal thrusts(Heimlich procedure) in the management of upperairway obstruction? Which of these procedures is mostappropriate for a 3-year-old child?

4. A 17-year-old boy was driving his minibike at highspeed along a country lane, when he suddenly saw whathe thought was a shortcut through a gap in a hedge. Hedid not see that the gap was closed by a strand of barbedwire. He struck the wire with his neck and was thrownfrom the bicycle. On arrival at the emergency depart-ment, he had all the signs and symptoms of upper air-way obstruction. Using your knowledge of the anatomyof the neck, explain the type of injury that could haveoccurred in this case. Does the position of the vocalcords at the time of impact influence the type of injurythat occurs? What anatomic factors normally protect

the upper airway from serious blunt injuries? Does ageplay a role in the severity of the injury?

5. A 39-year-old man with extensive maxillofacial injuriesfollowing an automobile accident was brought to thehospital. Evaluation of the airway revealed partialobstruction. Despite an obvious fractured mandible, anattempt was made to move the tongue forward from theposterior pharyngeal wall by pushing the angles ofthe mandible forward. This maneuver failed to movethe tongue, and it became necessary to hold the tongueforward directly in order to pull it away from the poste-

rior pharyngeal wall. At times, why is it not possible topull the tongue forward in the presence of a fracturedmandible?

6. When a laryngoscope is passed it is important to alignthe mouth, the oropharynx, and the larynx into oneplane. How do you bring the axes of the oropharynxand the larynx in line? How do you bring the axis ofthe mouth in line with the other axes? Describe thestructures in the order that you can view them througha laryngoscope from the base of the tongue down tothe trachea.

The Upper and Lower Airway and Associated Structures 33

4. The impact of the wire to the front of the neck causedhyperextension of the cervical part of the vertebral col-umn with stretching of the larynx and trachea. This ef-fectively fixed the airway structures in the midline sothat they were not deflected laterally at the moment ofimpact. Under these circumstances the cartilages of thelarynx are fractured or crushed. Depending on thespeed of the impact, the larynx could be completelyavulsed from the trachea. In this situation the tone ofthe suprahyoid muscles would cause the larynx to be re-tracted superiorly and the elasticity of the tracheawould cause it to retract inferiorly to the root of the neckor behind the sternum.

If the glottis were closed at the time of impact,the raised intraluminal pressure within the upperairway may contribute to the severity of the injury.The upper airway receives a considerable amount ofprotection from blows to the front of the neck andchest because of the presence of the mandible andmanubrium sterni. With the head and neck in theflexed position, the larynx and trachea are remarkablymobile and often deflected laterally by an anteriorblow to the neck.

In children, the very flexible nature of the laryngeal andtracheal cartilages and looseness of the supporting con-nective tissue reduce the likelihood of severe damage tothese structures.

5. The root of the tongue is attached anteriorly to themental spines on the posterior surface of the symph-ysis menti of the mandible by the right and leftgenioglossus muscles. If this bony origin were floatingbecause of fractures on both sides of the body of the mandible, pulling the angles of the mandible for-ward would have no effect on the position of thetongue.

1. The most common cause for difficulty in passing anasal tube is a deflected nasal septum. This occursmore commonly in the male, and is thought to be dueto previous trauma to the septum during the period ofactive growth. Nasal spurs and polyps may cause diffi-culty and swelling of the mucous membrane secondaryto infection or chemical irritation, and can also causeblockage. The widest part of the nasal cavity is near the floor.

2. The lymphoid tissue around the openings of the mouthand nasal cavities into the pharynx include (1) the pala-tine tonsil, (2) the lingual tonsil, (3) the tubal tonsils,and (4) the pharyngeal tonsil. For details of Waldeyer’sring, see text Chapter 2.

3. The presence of severe respiratory distress with supraster-nal retractions and aphonia indicates the presence of up-per airway obstruction, probably located within thelarynx. The airway is protected by a number of importantreflexes, including the gag reflex, the laryngeal reflex,and the cough reflex. The gag reflex occurs in responseto stimulation of the pharyngeal mucous membrane in-nervated by the glossopharyngeal nerve. The laryngealand the cough reflexes are mediated via the vagus nerve.These protective reflexes are lost in descending order asa patient loses consciousness.

All maneuvers that are directed toward freeing an ob-struction of the airway by an inhaled foreign body arebased on an attempt to increase the intrathoracic pres-sure by compressing the intrathoracic gas volume, sothat the foreign body is expressed from the mouth. Theunderlying mechanisms involved in the use of backblows, chest thrusts, and abdominal thrusts are dis-cussed in this CD chapter. It is now generally agreedthat the best and safest method to use on a 3-year-oldchild is the abdominal thrust.

Answers and Explanations

side of the median fold; (3) the upper edge of theepiglottis and the opening into the larynx, bounded infront by the epiglottis with its tubercle and laterally bythe aryepiglottic folds—the rounded elevations ofthe cuneiform and corniculate cartilages in the foldscan be recognized; (4) the reddish fixed vestibular folds;(5) the whitish mobile vocal cords; and (6) below theglottis the interior of the trachea with the upper two orthree rings.

6. The axis of the oropharynx and the larynx are broughtinto direct line by flexing the cervical part of the verte-bral column. The axis of the mouth is brought in linewith the oropharynx by extending the atlantooccipitaljoints.

The following structures may be viewed: (1) the base ofthe tongue; (2) the median glossoepiglottic fold, the twolateral glossoepiglottic folds, and the valleculae on each

34 Chapter 2