INTRODUCTION 
Cricothyroid space is the indentation between the thyroid and 
cricoids cartilages and is covered by the anterior/median 
cricothyroid ligament, a useful site for emergency access to 
the airway in cases of obstruction at or above the vocal cords 

1(cricothyroid puncture or cricothyroidotomy).  In the neonate, 
the dimensions of the cricothyroid membrane are too small to 

1allow safe passage of an airway.  The surface anatomy of the 
region is essential prior to performing a tracheostomy, 
cricothyroid puncture or cricothyroidotomy.

The American Society of Anes-thesiologists (ASA) and the 
DifcultAirway Society (DAS) provided frameworks for the 
anaesthetist to manage the unanticipated difcult airway and 
both guidelines end with the 'can't intubate, can't ventilate' 
(CICV) scenario, recommending either a needle or surgical 

 2, 3cricothyroidotomy as the next step.  

The laryngeal prominence (Adam's apple) of the thyroid 
cartilage is palpable in the midline neck, and the thyroid 
laminae can be felt passing posterolaterally. In the male, the 
prominence is usually visible, whereas in the female it is not 
usually apparent. The curved upper border of the thyroid 
cartilage, the midline thyroid notch and the superiorly located 
depression of the thyrohyoid membrane/ligament are easily 

1palpable.  The upper border of the thyroid cartilage usually 
4lies between the fourth and fth cervical vertebrae.  The rm, 

smooth anterior arch of the cricoid cartilage is palpable below 
the inferior border of the thyroid cartilage. The inferior border 
of the cricoid commonly sits at the level of the seventh cervical 
vertebra (range C5–T1); the posterior cricoid overlaps the 

4sixth cervical vertebra.

The aim of the present study was to collect data on the 
cricothyroid space in Indian population by measuring the 
height & width of the cricothyroid space and also measure 
anterior length of larynx.

MATERIALS 
Sixty apparently healthy looking specimens (51 males and 9 
females) were obtained from embalmed cadavers from a 
tertiary care teaching institute. All the cadavers were adult 
ranging between the age group of 18-65 years. The study 
consisted of meticulous dissection using standard dissection 
kit. In each cadaver, the larynx was looked for any gross 
deformity and specimens were selectively included in this 

study. The study was done only after due permission from the 
ethics committee of the institution.

METHODS
After the MBBS students had nished the dissection of face 
and the triangles of the neck the specimens were obtained. 
The sternohyoid and omohyoid muscles were cut and 
reected down from its insertion near the hyoid bone and after 
which the sternothyroid and thyrohyoid muscle was separated 
from the oblique line of thyroid cartilage. The thyroid gland is 
cut and removed. As the mandible was already removed the 
styloglossus and stylopharyngeus muscles were cut and then 
the constrictor muscles of the pharynx were incised. The 
trachea was transected between the fth and sixth tracheal 
rings along with the oesophagus. This completes the 
separation and the larynx specimen was recovered along with 
tongue, hyoid bone, proximal trachea, pharynx and proximal 
part of oesophagus. Then the epiglottis was separated from 
tongue by cutting the medial and lateral glossoepiglottic 
folds. The thyrohyoid membrane was cut to separate the hyoid 
bone from the thyroid cartilage. The specimen was cleaned to 
remove the extra laryngeal soft tissue so that all the laryngeal 
landmarks used in this study were easily seen. At the last the 
trachea rings were removed from the caudal end of the cricoid 
cartilage.

Measurements were made with a Vernier caliper (0 – 150 mm 
with a precision of 0.02 mm). The distance between the lower 
border of thyroid cartilage to upper border of cricoid arch 
(Height of cricothyroid space) was measured by the vernier 
caliper in anterior midline as seen in the gure 1 (Left Side)

The linear distance between the midpoint of cricoid & thyroid 
was measured by the vernier caliper (transverse width of 
cricothyroid space)

The distance between superior thyroid notch to lower border of 
cricoid cartilage is measured in anterior midline by vernier 
caliper as shown in gure 1 (right side) 

Fig 1 – Measurement of distance between the lower border 
of thyroid cartilage to upper border of cricoid arch(Left Side) 

CADAVERIC STUDY OF CRICOTHYROID SPACE – ANATOMICAL 
PERSPECTIVE

Original Research Paper

Dr. Parmanand 
Agarwal

Assistant Professor, Department Of Anatomy, GMC Ambikapur

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Anatomy

Cricothyroid space is the indentation between the thyroid and cricoids cartilages and is covered by the 
anterior/median cricothyroid ligament, a useful site for emergency access to the airway. The aim of the 

present study was to collect data on the cricothyroid space in Indian population by measuring the height & width of the 
cricothyroid space and also measure anterior length of larynx. Sixty apparently healthy looking specimens were obtained from 
embalmed cadavers. Height of cricothyroid space ranged from 6.64 - 12.56 mm, Transverse width of cricothyroid space ranged 
from 9.8 – 18.9 and length of larynx in anterior midline ranged from 27.12 - 42.96 mm. understanding of the dimensions and 
crucial anatomy of the cricothyroid space and related area is important to avoid or manage complications during surgical 
cricothyroidotomy. The dimensions are variable in different population, there is scope for more such study to corroborate these 
ndings and its clinical relevance.

ABSTRACT

KEYWORDS : Cricothyroid Space, Tracheostomy, Cricothyroidotomy, Cricothyroid Membrane

Dr. Yuvaraj J 
Bhosale*

Additional Professor, Department Of Anatomy, LTM Medical College, Sion 
Mumbai *Corresponding Author

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24 X GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS

and distance between superior thyroid notch to lower 
border of cricoid cartilage (Right Side)

RESULTS
The study pertaining to measurements of dimensions of 
cricothyroid space and also total length of larynx taking 
various landmarks on the cartilages as reference points was 
done in laryngeal specimens obtained from 60 cadavers. Of 
these 60 cadavers, 9 were females. Following observations 
were made: 
The distance between lower border of thyroid cartilage to 
upper border of cricoid arch (Height of cricothyroid space) in 
the anterior midline ranged from 6.64 - 12.56 mm with a mean 
of 8.98 ± 1.60 mm in males and ranged from 5.18 - 10.38 with a 
mean of 7.79 ± 1.61 mm in females. The frequency distribution 
of the distance showed that 70.1% of the values were between 
7-10 mm in males and 77.7% of the values were in the range of 
6-10 in mm.

The linear distance between the midpoint of cricoid & thyroid 
was measured by the vernier caliper (transverse width of 
cricothyroid space) ranged from 9.8 – 18.9 with a mean of 12.38 
± 1.94 in males and ranged from 6.1 – 11.7 with a mean of 8.92 
± 2.17 in females.

The distance between superior thyroid notch to lower border of 
cricoid cartilage ranged from 27.12 - 42.96 mm with a mean of 
34.40 ± 2.83 mm in males and ranged from 24.26 - 30.18 mm 
with a mean of 27.10 ± 2.11 mm in females.

DISCUSSION
Cricothyroid space is a space in between the lower border of 
thyroid cartilage and upper border of cricoid. The space has a 
membrane connecting the two margins. Puncture of the 
membrane is a component of several important clinical 
procedures. These include cricothyroidotomy, botox injection 
into vocal cord for patients with adductor spasmodic 
dysphonia, scintigraphic measurement of tracheal mucus 
velocity in patients with muco-ciliary dyskinesia, retrograde 
intubation of larynx, intraoperative neuromonitering of the 
recurrent laryngeal nerve during thyroid surgery, 
minitracheostomy for clearance of excess tracheobronchial 
secretions and percutaneous collagen augmentation for 
treatment of parkinsonian hypophonia. Carcinoma of larynx 
spreads extralaryngeally by invading the cricothyroid 

5membrane.

Develi et al stated that on the upper half and lower left 
quadrant of the cricothyroid membrane important vital 
anatomical structures (cricothyroid vessels, pyramidal lobe of 
thyroid gland) were mostly located. They further recommend 
that the lower right quadrant of the membrane is safer for 
invasive procedures such as needle cricothyroidotomy or 

6other cannulation techniques.          

TABLE 1: Comparison of mean distance between lower 
border of thyroid cartilage to upper border of cricoid 
cartilage with other studies (Height)

The mean distance between lower border of thyroid cartilage 
to upper border of cricoid cartilage was greater than the study 

8done on senile population by Zieli�ski R  and Prithishkumar et 
11 7 9al  and was lesser than the Dover et al  Tayama et al , Embate 

10 12 13JRS et al , Yadav Y  Anand V  study. In present study the 
distance was more in males than females in accordance with 

8all other except Zieliński R .

The mean linear distance between the midpoint of cricoid & 
7thyroid (Width) was found to be greater than Dover et al  and 

11 13Prithishkumar et al  but slightly lesser than Anand V et al . In 
present study the distance was more in males than females in 
accordance with all other study. 

TABLE 2 : Comparison of mean distance from superior 
thyroid notch to lower border of cricoid cartilage with other 
studies ( Length of Larynx in Anterior midline)

The values of mean distance from superior thyroid notch to 
lower border of cricoid cartilage in our study are 

16approximately similar to Eckel et al . It was lower than values 
14 15of Ajmani and Williams RG et al . There was a difference of 6 

to 7 mm in male and female as evident from the above table. 
Williams RG et al also measured the distance on volunteers it 

15was 46.1 mm in males and 38 mm in females.  Joshi et al 
reported the distance as 32.42 ± 3.41 mm which was the 

18inclusive of both genders.  

Williams RG et al stated that measurement of superior thyroid 
notch to lower border of cricoid cartilage acts as a surface 
landmarks in humans and because the vocal fold reach 
across the two cartilage and therefore if either of them were 
abnormally large or small this might affect the size of vocal 
fold, such a change in vocal fold could therefore be missed 

15only if one cartilage was measured.  

CONCLUSIONS
Whenever rapid access to the airway is required, especially in 
case of trauma or difcult thyroidectomy, cricothyroidotomy is 
the procedure of choice. Placing outsized tubes results in 
fracture of the laryngeal cartilages and later dysphonia and 

19-21subglottic stenosis.

So, understanding of the dimensions and crucial anatomy of 
the cricothyroid space and related area is important to avoid 
or manage complications during surgical cricothyroidotomy. 
The dimensions are variable in different population of 
different countries, so there is scope for more such study to 
corroborate these ndings and its clinical relevance.

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