What is the 3 3 2 rule for intubation?
Using the fingers held together, assess the distance from the hyoid bone to the chin (should be at least three fingers) and the distance from the thyroid cartilage to the floor of the mouth (at least two fingers). Any measurement that is less than 3-3-2 indicates potential difficulty with airway management.
What is hyoid mental distance?
A typical patient can place three fingers on the floor of the mandible between the mental angle and the neck near the hyoid bone. Normally this distance should measure close to 7 cm.
What is Mentohyoid distance?
Mentohyoid distance: It was measured from the tip of the jaw to the hyoid bone with head extended and mouth closed. Sternomental distance: It was measured with patients seated erect with head fully extended over neck and mouth closed.
What is Sternomental distance?
Sternomental distance (SMD) is an indicator of head and neck mobility. [1] It has been suggested as the best single test for ruling out difficult intubation among forced protrusion of the mandible, inter-incisor gap, modified Mallampati grade, and thyromental distance (TMD).
How do you predict a difficult airway?
The distance from the thyroid notch to the mentum (thyromental distance), the distance from the upper border of the manubrium sterni to the mentum (sternomental distance), and a simple summation of risk factors (Wilson risk sum score) are widely recognized as tools for predicting difficult intubation.
What is the hyoid?
The hyoid bone (hyoid) is a small U-shaped (horseshoe-shaped) solitary bone, situated in the midline of the neck anteriorly at the base of the mandible and posteriorly at the fourth cervical vertebra. Its anatomical position is just superior to the thyroid cartilage.
How do you measure Sternomental distance?
Sternomental distance (SMD): It is defined as the distance from the suprasternal notch to the mentum and is measured with the head fully extended on the neck and the mouth closed.
What causes difficult airway?
There are many underlying causes of difficult airway management, including facial deformity, cervical spine injury, airway hemorrhage, and uncooperativeness or combativeness on the part of the patient.
How many ossification centres does the hyoid bone have?
Like the other parts of the hyoid bone the lesser cornua have two ossification centres, giving a total of six ossification centres. The apical part of the greater cornua may not complete ossification until the patient is in their twenties. The primary role of the hyoid bone is to provide stability to adjacent structures via the attached muscles.
Where is the geniohyoid located in the hyoid bone?
Geniohyoid originates at the genial tubercle (inferior mental spine) of the mandible. The slender muscle continues inferiorly to insert on the anterior surface of the body of the hyoid bone. The bilaterally paired muscle lies between mylohyoid and genioglossus (base of the tongue). C1 fibers of the hypoglossal nerve (CN XII) innervate the muscle.
Where does the Greater Horn of the hyoid originate?
The greater horn arises from the third arch, while the lesser horn originates from the second arch. Fusion of both cornua results in the formation of the body of the hyoid. Chondrocytes begin the process of making the tissue cartilaginous (chondrification) by the fifth week of intrauterine life.
Where does the digastric muscle originate in the hyoid bone?
The digastric muscle has a posterior and an anterior belly. The posterior belly originates in the digastric groove on the medial aspect of the mastoid process. It travels anteroinferiorly toward its insertion in the intermediate tendon at the junction of the greater cornu and body of the hyoid bone.
