TO STUDY THE TERMINAL DEVISION OF RECURRENT LARYNGEAL NERVE AND ITS VARIATION IN COMPARISION OF INFERIOR THYROID ARTERY
Authors: Yadav Rahul , S Siva , Raj Yadav Ram , Mishra Vivek , Saroj Sanjay , N Chandel Swati , Pamei Achambou , Srivastava Shikhar , Birhade Mayur , Singh Aman , Varsha Varsha , Singh Royana , Kumar Rajesh 
Published: February 2025

The vagus nerve, which supplies the larynx with motor,
sensory, and parasympathetic bers, branches into the
recurrent laryngeal nerve (RLN) and Superior Laryngeal
nerve. Before ascending behind the inferior constrictor to the
nerve's entry location into the larynx, the RLN is regularly seen
in close relation to the inferior thyroid artery and its branches.
This association is a signicant turning point in its
identication in thyroid surgery patients. However, one wellknown risk factor for RLN injury after thyroid surgery is
anatomic abnormalities of the RLN. Acute airway obstruction
and stridor in cases of bilateral damage are two signs of RLN
paralysis, which can result from injury to the RLN and range
[1,2] from nearly undetectable hoarseness in unilateral lesions.
About 3-8% of cases result in transient post-operative RLN
[3-5] paralysis, while 0.3–3% of cases result in chronic paralysis.
Therefore, in order to protect the nerve and its function during
surgery, it is critical to recognize the anatomical variations of
the RLN. While advancements in monitoring have made it
possible to lower the incidence of RLN injury with
intraoperative neuromonitoring, visual identication of the
[6] RLN remains the gold standard for RLN injury avoidance . In
order to do thyroid surgery, it is crucial to ascertain the RLN's
anatomical location. The recurrent laryngeal nerves innervate
the majority of the muscles involved in vocal cord movement.
any lesion along the vagal nerves' route above the recurrent
laryngeal nerves' branching or along the recurrent laryngeal
nerves themselves can result in vocal cord paralysis (VCP).
Due to the vagal nerve's close relationship to other cranial
nerves at this level, an adverse lesion located in the brainstem
or skull base typically results in several cranial nerve
impairments. Isolated laryngeal complaints are often caused
by pathology involving the recurrent laryngeal nerves and/or
the extracranial vagal nerves. Numerous pathological
conditions might result in VCP because of the vagal and
recurrent laryngeal nerves' lengthy anatomical courses. VCP
can be brought on by surgery, cancer, trauma, infection, and
inammation. The most common cause of VCP, according to a
survey of over 800 patients, is iatrogenic damage during
[7] mediastinal and neck surgery. laryngoscopy can be used to
evaluate vocal cord function. During this procedure, a
stroboscopic light can be used to conrm that the aficted side
is immobile. Hoarseness, vocal tiredness, loss of voice pitch,
dyspnea, and aspiration are among the signs and symptoms
[8] of VCP. Nonetheless, between 30 and 40 percent of patients
[9, 10] with unilateral VCP have no symptoms. While the recurrent
laryngeal nerve is the main efferent branch of the vagus nerve,
the external branch of the superior laryngeal nerve is
particularly signicant because it can sustain damage from
post-operative inammation, tethering, or scarring, or from
[11, 12]
surgical injury during thyroid or carotid endarterectomy.
Due to the loss of efferent bers to the cricothyroid muscle
(CT), iatrogenic injury to the external branch of the superior
laryngeal nerve (EBSLN) typically causes hoarseness, poor
[13] sound, and vocal fatigue. The frequency of EBSLN injury
varies from 0% to 58% as a result of differing postoperative
[14] assessments and surgical procedures. Furthermore, there
[15] aren't many trustworthy anatomical landmarks in the area.