2. Airway
The passage through which the air passes
during respiration. It includes
upper airway-
Mouth
Nasopharynx (nasal cavity, septum, turbinates, adenoids
Oropharynx (oral cavity, teeth, tongue)
Pharynx (tonsils, uvula, epiglottis)
lower airway-
trachea, bronchi, bronchioles, alveoli
3. Why it is necessary ?
⚫ Respiratory events are the most common anaesthetic
related injuries, following dental damage. Three main
causes:
◦ Inadequate ventilation
◦ Oesophageal intubation
◦ Difficult tracheal intubation
⚫ Difficult tracheal intubation accounts for 17% of the
respiratory related injuries and results in significant
morbidity and mortality.
⚫ Estimated that up to 28% of all anaesthetic related deaths
are secondary to the inability to mask ventilate or
intubate.
⚫ Prediction of the difficult airway allows time for
optimal patient preparation, proper selection of
equipment, technique and personnel experienced in
difficult airways
4. Difficult airway
ASA definition of difficult airway:
―The clinical situation in which a
conventionally trained anaesthetist
experiences difficulty with mask
ventilation, difficulty with tracheal
intubation or both.‖
5. Difficult mask ventilation
When it is not possible for the unassisted
anesthesiologist to maintain oxygen
saturation more than 90% using 100%
oxygen and positive pressure mask
ventilation in a patient whose oxygen
saturation was more than 90% before
anaesthetic intervention; and/or, it is not
possible for the unassisted
anesthesiologist to prevent or reverse
signs of inadequate ventilation during
positive pressure mask ventilation.
6. ⚫More than 3 attempts
⚫Longer than 10 minutes
⚫Failure of optimal best attempt at
laryngoscopy- laryngoscopy
performed by a reasonably
experienced laryngoscopist with the
patient in optimal sniff position having
no significant muscle tone and the
laryngoscopist has an option of
change of blade type and length (one
Difficult endotracheal intubation
7. Intubation attempt
Intubation activities occurring during a
single continuous laryngoscopy
maneuver. Thus even if several attempts
were made to place an ETT during the
course of a single laryngoscopy, this
would be counted as a single intubation
attempt.
8. Rapid sequence intubation
This is a technique of endotracheal intubation
adopted in patients who are not fasted and are
therefore at risk of aspiration of the gastric
contents. It can be defined as “Administration
of fixed dose of induction agent and short
acting muscle relaxant after preoxygenation,
and intubation of the trachea without
interposed assisted ventilation.”
9. Prevalence
⚫Difficult face mask
◦ 0.1% - 5%
⚫Difficult LMA
◦ 0.2% - 1%
⚫Difficult intubation
◦ 1-2% of normal surgical population
◦ 50% of rheumatic cervical disease
10. ⚫ Nostril patency
⚫ Length of the upper incisors, alignment
⚫ Condition of the teeth
⚫ Relationship of the upper (maxillary) incisors
to the
lower (mandibular) incisors
⚫ Ability to protrude or advance the lower (mandibular)
incisors in front of the upper (maxillary) incisors
⚫ Interincisor or intergum (if edentulous) distance
⚫ Tongue size
⚫ Visibility of the uvula e.g. mallampati
⚫ Presence of heavy facial hair
⚫ Compliance of the mandibular space
⚫ Thyromental distance with the head in maximum
extension
⚫ Length of the neck
⚫ Thickness or circumference of the neck
⚫ Range of motion of the head and neck
⚫ Cheek pad
Components of airway examination
11. Causes of difficult
airway
⚫ Stiffness
◦ Arthritis of neck/jaw/larynx.
◦ Fixation devices
◦ Scleroderma
◦ Diabetes
⚫ Deformity
◦ Cervical and craniofacial
◦ Burns/trauma/infection
⚫ Swelling
◦ Infection/tumour/trauma/burns
◦ Anaphylaxis/haematoma/acromegaly
⚫ Reflexes
◦ Cough/breathholding
◦ Laryngospasm/salivation/regurgitation
⚫ Foreign body
⚫ Other – Pregnant/full stomach
12. Anomaly/pathology affecting upper airway management
1.Facial anomalies:
a) Maxillary hypoplasia (Apert syndrome, Crouzon disease)
b) Mandibular hypoplasia (Pierre robin syndrome, Treacher Collin
syndrome, Goldenhar syndrome.
c) Mandibular hyperplasia (Acromegaly, Cherubism)
2. Temporomandibular joint pathology: Ankylosis or reduced
movement (congenital, traumatic, infective)
3. Anomalies of the mouth and tongue:
a) Microstomia (burns, trauma scarring)
b) Disease of the tongue (burns, trauma, ludwigs angina) all leading
to tongue swelling
c) Tumors of the mouth and tongue (hemangioma, lymphangioma)
d) Macroglossia ( Downs syndrome, hypothyroidism)
4. Problem with teeth (missing left upper incisors, protruding upper
incisors)
13. 5. Anomaly/pathology of nose:
a) Choanal atresia
b) Hypertrophic turbinates and deviated nasal septum
c) Tumors (polyps, gliomas) and foreign bodies
6. Pathology of the palate:
a) Narrow arched palate
b) Large cleft defects
c) Soft palatal swelling and hematomas.
7. Pathology of the pharynx:
a) Hypertrophic tonsils and adenoids
b) Tumors and abscess
c) Retropharygeal and/or parapharygeal abscess.
8. Pathology of larynx:
a) Supraglottic: epiglottitis
b) Laryngomalacia, granulomas,foreign body, papillomas
c) Infraglottic: congenital stenosis, traumatic stenosis, inflammatory edema
14. Lower airway pathology:
1.Tracheal pathology:
a) Tracheatis
b) Tracheo-esophageal fistula
c) Tracheal stenosis
d) Tracheal webbing
e) Foreign bodies
f) Tracheomalacia
g) Mass lesion of neck or mediastinal mass deviating
trachea
2. Bronchial tree pathology:
a) Mediastinal masses distorting bronchi
b) Foreign body aspiration
c) Bronchial tumors
15. Disease states of the neck and cervical spine
Neck- Large goitre, abscesses,skin contractures
Spine-
1) Limitation of movement (congenital-Klippel-feil
syndrome; acquired-surgical fusion, fracture of cervical
vertebrae
2) Cervical spine instability: Down syndrome, traumatic
subluxation
16. Airway assessment
⚫ History
◦ Patient/notes
🞄 Difficulty
🞄 Surgery/burns
🞄 Concurrent disease
🞄 Reflux/recent meals
⚫ General examination
◦ Do they just look difficult?
🞄 Dentition (prominent upper incisors, receding chin)
🞄 Distortion (edema, blood, vomits, tumor, infection)
🞄 Disproportion (short chin-to-larynx distance, bull neck, large tongue, small
mouth)
🞄 Dysmobility (TMJ and cervical spine)
◦ Massively obese or pregnant
◦ Beards +/- tubes
⚫ Specific tests/indices
⚫ Investigations.
◦ Nasoendoscopy
◦ X-ray, CT/MRI
◦ Flow volume loop
17. How do you assess ??
The airway may be assessed for difficult airway using
:-
-Individual indices
-Group indices(with and without scoring)
Mask ventilation precedes laryngoscopy, which inturn
followed by, intubation.
So the assessment should be in a systemic manner.
18. Predictors of difficulty to
face mask ventilate
(OBESE)
1.The Bearded
2.The Obese (BMI->26 Kg/m2)
3.No teeth
4.The Elderly (older than 55 y)
5.The Snorers
6.The Edentulous
(=BONES)
19. Predictors of difficulty to
face mask ventilate
(MOANS)
⚫ MOANS
This is identicle to BONES except ‗M‘.
-Mask seal difficult due to receding
mandible,syndromes with facial abnormalities,burn
stricture etc.
-Obesity, upper airway Obstruction
-Advanced age
-No teeth
-Snorer
20. Predictors of difficult
laryngoscopy and intubation
Individual indices
-Physical examination indices
-radiological indices
-advanced indices
Group indices
- Wilson‘s score
- Benumof‘s analysis
- Saghei & safavi test
- Lemon assesment
- Arne‘s simplified score
- Magboul‘s 4 M‘s
21. Atlanto-occipital movement
⚫ The patient is asked to hold head erect, facing directly to the front,
then he is asked to extend the head maximally and the examiner
estimates the angle traversed by the occlusal surface of upper
teeth.
◦ Visual assessment or using a goniometer.
🞄 Grade I >35 degrees
🞄 Grade II 22-34 degrees
🞄 Grade III 12–21 degrees
🞄 Grade IV <12 degrees
⚫ Assesses feasibility to make the optimal intubation position with
alignment of oral, pharyngeal and laryngeal axes into a straight
line.
⚫ Limited A-O joint extension
◦ Spondylosis, rheumatoid arthritis, halo-jacket fixation, and in patients
with symptoms indicating nerve compression with cervical extension.
22. Grade Reduction of A.O.Extension
1 none
2 One third
3 Two third
4 complete
Grades 3 and 4 : Difficult laryngoscopy
Grading of reduction in A.O.Extension
Grade I :
Grade II :
Grade III :
Grade IV:
> 35°
22-34°
12-21°
< 12°
23. • Flexion movement of the cervical spine can be
assessed by asking the patient to touch his manubrium
sternii with his chin. If done, the above maneuver
assures a neck flexion of 25- 35 degree. Flexion and the
extension movement if within the normal range ,three
axis ( oral,pharyngeal & laryngeal axis) can be brought
• ASSESMENT OF A.O. EXTENSION
can also be done by asking the patient to look at
the floor and at wall after fully flexing and fixing the
neck as shown
24. Warning sign of DELIKAN
Place the index finger of each hand, one underneath
the chin and one under the inferior occipital
prominence with the head in neutral position. The
patient is asked to fully extend the head on neck. If
the finger under the chin is seen to be higher than the
other, there would appear to be no difficulty with
intubation. If level of both fingers remains same or the
chin finger remains lower than the
-: other, increased difficulty is predicted.
25. PRAYER SIGN
A positive "prayer sign" can be
elicited on examination with the
patient unable to approximate
the palmar surfaces of the
phalangeal joints while pressing
their hands together.
Seen in diabeties
; This represents:- cervical spine
immobility and the potential for
a difficult endotracheal
intubation.
26. Palm Print test
The palm and fingers of the dominant hand of the
patient is painted with black writing ink using a brush.
The patient then presses the hand firmly against a white
sheet of paper on a hard surface. Scoring is done as:
* Grade 0 -All phalangeal areas visible.
* Grade 1 - Deficiency in the inter-phalangeal areas of
4th and/or 5thdigit.
* Grade2 - Deficiency in the inter-phalangeal areas of
2nd to 5th digit.
* Grade 3 - Only the tips of digits seen.
28. ASSESSMENT OF TMJ FUNCTION
TM joint exhibits 2 function.
1.
2.
Rotation of the condyle in the s.cavity.
Forward displacement of the condyle.
First movement is responsible for 2-3cm mouth opening
& the second is responsible for further 2-3cm mouth
opening.
Index finger is placed in front of the tragus & the thumb is
placed in front of the the lower part of the mastoid process.
patient is asked to open his mouth as wide as possible. Index
finger in front of the tragus can be intented in its space and
the thumb can feel the sliding movement of the condyle as
the condyle of the mandible slides forward.
SUBLUXATION OF THE MANDIBLE
30. Assessment of mandibular
space
⚫can be expressed as thyromental and
hyomental space.
⚫This space determines how easily the
laryngeal and pharyngeal axis will fall
in line when the a-o joint is extended.
31. Thyromental Distance
This is the distance between the thyroid notch
and mental symphysis when the neck is fully
extended
>6.5cm: no problem with laryngoscopy and
intubation
6.0 -6.5 cm: without other concomitant
anatomical problems, laryngoscopy and
Intubation are difficult but possible.
<6.0cm: laryngoscopy may be impossible
32. Limitations
⚫ Little reliability in prediction
⚫ Variation according to height, ethnicity
Modification to improve the accuracy
⚫ Ratio of height to thyromental distance (RHTMD)
⚫ Useful bedside screening test
⚫ RHTMD > 23.5 – very sensitive predictor of difficult
laryngoscopy
Thyromental Distance
PA
TIL’S TEST
33. HYO MENTAL DISTANCE
⚫ Distance between mentum
and hyoid bone
⚫ Grade I :
⚫ Grade II:
> 6cm
4 – 6cm
⚫ Grade III : < 4cm –
Impossible laryngoscopy &
Intubation
34. INTER-INCISOR GAP
⚫ Inter-incisor distance with maximal mouth
opening
⚫ Normal value > 5 cm / admits 3 fingers.
• Significance :
⚫ Positive results: Easy insertion of a
3 cm deep flange of the
laryngoscope blade
⚫ < 3 cm: difficult laryngoscopy
⚫ < 2 cm: difficult LMA insertion
⚫ Affected by TMJ and upper cervical spine
mobility
35. STERNOMENTAL DISTANCE (SAVVA
TEST)
⚫ Distance from the upper border of the manubrium
to the tip of mentum, neck fully extended, mouth
closed
⚫ Minimal acceptable value – 12.5 cm
⚫ Single best predictor of difficult laryngoscopy and
intubation ( Has high sensitivity & specificity).
36. UPPER LIP BITE /CATCH
TEST
⚫ Class I: Lower incisors can bite the upper lip above
vermilion line
⚫ Class II: can bite the upper lip below vermilion line
⚫ Class III: cannot bite the upper lip
Significance
⚫ Assessment of mandibular movement and dental
architecture
⚫ Less inter observer variability
37. Test for assessing adequacy of the
oropharynx for laryngoscopy and
intubation
⚫Mallampati grading (samsoon and young‘s
modification)
⚫Narrowness of the palate
38. Mallampati Score
Sensitivity: 44% - 81%
Specificity: 60% - 80%
Roughly corresponds to Cormack and Lehane‘s
laryngoscopy views
⚫ Class I (easy)—visualization of the soft
palate, fauces, uvula, and both anterior and
posterior pillars
Class II—visualization of the soft palate, ,
and uvula
Class III—visualization of the soft palate and the
base of the uvula
Class IV (difficult)—the soft palate is not visible at all, only
hard palate is visible
39.
40. SIGNIFICANCE OF MMP SCORE
⚫ Class III or IV: signifies that the angle between
the base of tongue and laryngeal inlet is more
acute and not conducive for easy laryngoscopy
⚫ Limitations
◦ Poor interobserver reliability
◦ Limited accuracy
⚫ Good predictor in pregnancy, obesity, acromegaly
41. Assessment for quality of
glottic viewing during
laryngoscopy
• Indirect mirror laryngoscopic view Direct
laryngoscopy ‗awake look‘
• -cormack and lehane grading
Grading ease of intubation
• POGO (percentage of glottic opening) scoring
42. CORMACK - LEHANE
Grading at direct laryngoscopy
⚫ Grade 1: Full exposure of glottis (anterior + posterior
commissure)
Grade 2:
Grade3:
Grade 4:
posterior commissure visualised
Epiglottis visible
No glottic structure visible.
Grade I = success & ease of intubation
43.
44. Group indices
- Wilson‘s score
- Benumof‘s analysis
- Saghei & safavi test
- Lemon assesment
- Arne‘s simplified score
- Magboul‘s 4 M‘s
- 4D‘s
45. Wilson‘s risk score
Score
0=<90kg
1=>90kg
2=>110kg
0=Above 90degrees
1=About 90degrees
2=Below 90degrees
0=Normal
1=Moderate
2=Severe
0=Normal
1=Moderate
2=Severe
•Head movement assessed
with pencil taped to a
patient’s forehead.
•IG = Interincisor gap
measured with mouth fully
open.
•SLux = Maximal forward
protrusion of the lower
incisors beyond the upper
incisors.
•score 5 or < =easy laryngoscopy
•Score 8-10 =severe difficulty in
laryngoscopy
46. BENUMOF’S 11 PARAMETER ANALYSIS
Parameter Minimum acceptable
value
<1.5cm
Absent
Yes
No arching/narrowness
1. Buck teeth
2. Subluxation
3. Interincisor gap >3 cm
4. Palate configuration >3cm
5. Mallampati class
6. Upper inciors length <1.5cm
7. TM distance
8. SMS compliance
9. Neck thickness
10. Length of neck
11. Head /neck mvt
> 5cm
Soft to palpation.
Qualitative ( >33cm DI)
>8cm
Normal range
4-2-2-3 rule
4 for tooth
2 for inside of mouth
2 for mandibular space
3 for neck examination.
47. SAGHEI & SAFAVI’S
⚫ Weight
⚫ Tongue protrusion
⚫ Mouth opening
⚫ Upper incisor length
⚫ Mallampati class
⚫ Head extension
• Any 3 indices if
present
• >80kg
• < 3.2cm
• <5cm
• >1.5cm
• >1
• <70 degree
• Prolonged
laryngoscopy
48. Arne’s simplified score
model
⚫ The points of simplified score were obtained by multiplying the points of the
exact score by 3.15 and then rounding the results to the nearest whole number.
⚫ Risk factor simplified score
⚫ Previous knowledge of difficult intubation
No
Yes
0
10
⚫ Pathologies associated with difficult intubation
0
No
Yes 5
⚫ Clinical symptoms of airway pathology
0
No
Yes 3
⚫ Inter-incisor gap (IG) and mandible luxatum (ML)
0
IG > 5 cm or ML >0
IG 3.5-5cm and ML=0
IG<3.5 cm and ML<0
3
13
49. Arne’s simplified score contd.
⚫ Thyromental distance
>6.5cm
< 6.5cm
simplified score
0
4
⚫ Maximum range of head & neck movement
Above 100° 0
About 90° (90° ± 10°) 2
Below 80° 5
⚫ Mallampati’s modified test
Class 1
Class 2
Class 3
Class 4
0
2
6
8
Total...... 48
Score of >11 is predictive of difficult tracheal intubation
Indian journal of anaesthesia,2002; 46(5) 347-352
50. LEMON trial
⚫Look
🞄 Facial trauma
🞄 Large incisors
🞄 Beard
🞄 Large tongue
⚫Evaluate 3-3-2
🞄 Interincisor distance (3 fingers)
🞄 Hyoidmental distance (3 fingers)
🞄 Thyroid to floor of mouth (2fingers)
⚫Mallampati
⚫Obstruction
⚫Neck movement – chin to chest
( Airway management in trauma
Indian J Anaesth. 2011 Sep-Oct; 55(5): 46)3–469)
51. LOOK Externally
⚫Beards or facial hair
⚫Short, fat neck
⚫Morbidly obese patients
⚫Facial or neck trauma
⚫Broken teeth (can lacerate balloons)
⚫Dentures (should be removed)
⚫Large teeth
⚫Protruding tongue
⚫A narrow or abnormally shaped face
52. EVALUATE 3-3-2
⚫Mouth Opens at least 3 finger widths.
⚫Three finger widths thyromental
distance.
⚫Two finger widths mandibulohyoid
distance.
54. Upper & Lower Face
⚫ Measure the size of the upper face as compared
to the lower face.
⚫ Should be roughly the same.
⚫ If the lower face is longer than the upper face then
you should anticipate some degree of difficulty
lining up the structures
56. Obstruction
⚫Laryngoscopy or intubation may be more
difficult in the presence of an obstruction
◦ Anatomy
◦ Trauma
◦ Foreign body obstruction
◦ Edema (burns)
57. Neck Mobility
⚫Ideally the neck should be able to
extend back approximately 35
⚫Problems:
◦ Cervical Spine Immobilization
◦ Ankylosing Spondylitis
◦ Rheumatoid Arthritis
◦ Halo fixation
58. Scene and Situation (SEE)
⚫Scene safety
⚫Environment
◦ Do you have a reasonable chance to get
the tube?
◦ Space, positioning, access
⚫Egress
◦ Will you be able to ventilate during
egress?
59. Magboul‘s 4 M‘s
⚫ For Intubation remember the 4(M & Ms) with (STOP) sign
⚫ Mallampati
⚫ Measurement
⚫ Movement
⚫ Malformation & STOP
⚫ M =Malformation of the skull, teeth, obstruction, & Pathology (the
Macros and Micros). We can memorize them with the word (STOP)
⚫ S = Skull (Hydro and Microcephalus)
⚫ T = Teeth (Buck, protruded, & loose teeth. Macro and Micro
mandibles)
⚫ O= Obstruction (due to obesity, short Bull Neck and swellings
around the head and neck)
⚫ P = Pathology (Craniofacial abnormalities & Syndromes: Treacher
Collins, Goldenhar's, Pierre Robin, Waardenburg syndromes) .
⚫ (The Internet Journal of Anesthesiology. 2005 Volume 10 Number 1.
DOI: 10.5580/1d0a)
60. What are the 4
Ds?
The following Four D's also suggest a difficult airway:
⚫ Dentition (prominent upper incisors, receding chin)
⚫ Distortion (edema, blood, vomits, tumor, infection)
⚫ Disproportion (short chin-to-larynx distance, bull
neck, large tongue, small mouth)
⚫ Dysmobility (TMJ and cervical spine)
61. al view) :
RADIOGRAPHIC
PREDICTORS
1. X-Ray neck (later
⚫ Occiput - C1 spinous process
distance< 5mm.
⚫ Increase in posterior mandible
depth > 2.5cm.
⚫ Ratio of effective mandibular
length to its posterior depth
<3.6.
⚫ Tracheal compression.
62. 2. CT Scan:
⚫ Tumors of floor of mouth, pharynx, larynx
⚫ Cervical spine trauma, inflammation
⚫ Mediastinal mass
3. Helical CT (3D-reconstruction):
⚫ Exact location and degree of airway compression
ADVANCED INDICES
• Flow volume loop
• Acoustic response measurement
• Ultra sound guided
• CT / MRI
• Flexible bronchoscope
68. How to predict difficult
placement of supraglottic devices
⚫Restricted mouth opening
⚫Obstruction of the upper airway
⚫Distrupted upper airway as following
trauma,burn,caustic ingestion .
⚫Stiff lung (poor lung or thoracic
compliance)
Suggested by Hung and Murphy
(Canadian journal of anesthesia 2004:10:963-8)
69. How to predict difficulty in
creating surgical airway
⚫Bleeding tendency
⚫Agitated patient
⚫Neck scarring
⚫Growth or vascular abnormality in
region of surgical airway.
70.
71.
72.
73.
74.
75.
76.
77. COPUR index assessing difficult airway in
paediatric patient
⚫ C-chin From the side view the chin is:
Normal
Small, moderately hypoplastic
Markedly recessive
Extremely hypoplastic
score
1
2
3
4
⚫ O-Opening of the mouth(Interdental space)
>40mm
20-40 mm
10-20mm
<10
1
2
3
4
⚫ P-Previous Intubation or OSA
Previous attempt easy 1
No previous attempt, no hx OSA 2
OSA, previous hx difficult intubation 3
Extremely difficult previous intubation, trach,
or patient unable to lie supine 4
78. COPUR index (contd)
⚫ U-Uvula (Mouth open tongue out)
Tip of uvula visible 1
Uvula partially visible 2
Uvula concealed, soft palate visible 3
Soft palate not visible 4
⚫ R Range (estimaterange of motion looking up and down)
>120°
60°-120°
30°-60°
< 30°
1
2
3
4
⚫ Prediction Points
⚫ 5-7 Easy normal intubation score >10 predict difficult airway
⚫ 8-10 laryngeal pressure may help
⚫ 12 more difficult, fiberoptic may be less traumatic
⚫ 14 Difficult intubation, fiberoptic or other advanced technique
⚫ 16 Dangerous airway, consider awake intubation, potential trach
79. Structured Approach to Airway
Management
⚫ MOUTHS
Component Description Assessment Activities
Mandible Length and subluxation Measure hyomental distance and
anterior displacement of mandible
Opening Base, symmetry, range Assess and measure mouth opening
in centimetres
Uvula Visibility Assess pharyngeal structures and
classify
Teeth Dentition Assess for presence of loose teeth
and dental appliances
Head Flexion, extension, rotation
of head/neck and cervical
spine
Assess all ranges and movement
Silhouette Upper body abnormalities,
both anterior and posterior
Identify potential impact on control
of airway of large breasts, buffalo
hump, kyphosis, etc.
80. Rule of 1-2-3
⚫ 1 finger breadth for subluxation of mandible. Just to
recall
⚫ 2 finger breatdh for adequacy of mouth opening.
⚫ 3 finger breathd for hyomental distance.
In emergency situation, above test can be rapidly performed within 15sec
to assess the TMJ function,mouth opening and SM Space. Significant
difficulty in 2 or more of these components requires detailed
examination.
• 4 finger breath for thyromental distance
• 5 movements- ability to flex the neck upto the manubrium sterni,
Rule of 1-2-3-4-5
extension at the AOJ, rotation of the head along with right & left
movement of the head to touch the shoulder.
RULE OF THREE`S
• 3 finger in the interdental space.
• 3 finger between mentum and hyoid bone.
• 3 finger between thyroid cartilage & sternum.
