Intralaryngeal neuroanatomy of the recurrent laryngeal nerve of the rabbit

J. Anat.

(2003)

202

, pp421–430

© Anatomical Society of Great Britain and Ireland 2003

Blackwell Science, Ltd

Intralaryngeal neuroanatomy of the recurrent laryngeal nerve of the rabbit

Stephen Ryan,

1

Walter T. McNicholas,

2

Ronan G. O’Regan

1

and Philip Nolan

1

1

Department of Human Anatomy and Physiology and

2

Department of Respiratory Medicine, Conway Institute for Biomolecular and Biomedical Research, University College Dublin

2

St. Vincent’s University Hospital, Dublin, Ireland

Abstract

We undertook this study to determine the detailed neuroanatomy of the terminal branches of the recurrent laryn-

geal nerve (RLN) in the rabbit to facilitate future neurophysiological recordings from identified branches of this

nerve. The whole larynx was isolated

post mortem

in 17 adult New Zealand White rabbits and prepared using a

modified Sihler’s technique, which stains axons and renders other tissues transparent so that nerve branches can

be seen in whole mount preparations. Of the 34 hemi-laryngeal preparations processed, 28 stained well and these

were dissected and used to characterize the neuroanatomy of the RLN. In most cases (23/28) the posterior cricoary-

tenoid muscle (PCA) was supplied by a single branch arising from the RLN, though in five PCA specimens there were

two or three separate branches to the PCA. The interarytenoid muscle (IA) was supplied by two parallel filaments

arising from the main trunk of the RLN rostral to the branch(es) to the PCA. The lateral cricoarytenoid muscle (LCA)

commonly received innervation from two fine twigs branching from the RLN main trunk and travelling laterally

towards the LCA. The remaining fibres of the RLN innervated the thyroarytenoid muscle (TA) and comprised two

distinct branches, one supplying the pars vocalis and the other branching extensively to supply the remainder of

the TA. No communicating anastomosis between the RLN and superior laryngeal nerve within the larynx was

found. Our results suggest it is feasible to make electrophysiological recordings from identified terminal branches

of the RLN supplying laryngeal adductor muscles separate from the branch or branches to the PCA. However, the

very small size of the motor nerves to the IA and LCA suggests that it would be very difficult to record selectively

from the nerve supply to individual laryngeal adductor muscles.

Key words

larynx; Sihler’s stain.

Introduction

The recurrent laryngeal nerve (RLN) provides the motor

innervation to all intrinsic laryngeal muscles except the

cricothyroid and is responsible for adjustments in glottic

aperture during the respiratory cycle. The pattern of

respiratory-related discharge observed from whole RLN

recordings is complex, exhibiting activity either exclu-

sively in inspiration or during both respiratory phases

(Green & Nail, 1955; Sica et al. 1984, 1985). As a result

interpretation of whole RLN motor activity in relation

to control and function of laryngeal abductor and

adductor muscles is difficult. Recordings obtained from

motor units in the RLN show that the RLN contains

functionally diverse groups of motoneurones (Sica

et al. 1985; Ryan et al. 2002). It is assumed that these

motoneurones are destined for different muscles groups

on the basis of discharge pattern and the known

electromyographic activity profiles and function of

laryngeal abductor and adductor muscles. RLN motor

units with post-inspiratory discharge are presumed to

innervate laryngeal adductor muscles (Bartlett et al.

1973; Ryan et al. 2002) while units with inspiratory-

related activity are assumed to supply the posterior

cricoarytenoid muscle (PCA), the principal abductor of

Correspondence

Dr Philip Nolan, Department of Human Anatomy and Physiology, Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland. Tel.: +353 17167466; fax: +353 17167417; e-mail: [email protected]

Accepted for publication

28 February 2003

Rabbit laryngeal neuroanatomy, S. Ryan et al.


422

the vocal cord. These assumptions may not be entirely

valid because (i) the action and functions of individual

laryngeal muscles are incompletely understood, (ii)

laryngeal adductor activity is not confined to expiration

(Insalaco et al. 1990) and (iii) the PCA exhibits tonic

expiratory activity on which phasic inspiratory activity

is superimposed (Sherrey & Megirian, 1980).

Care must be taken when interpreting recordings

obtained from motor units in the main trunk of the

RLN, as we cannot be certain of their final destination

within the larynx. Zhou et al. (1989) used a novel

approach to studying the motor control of laryngeal

muscles by recording separately from the intralaryn-

geal branches supplying the abductor and adductor

muscles. We intend to perform similar experiments in

our decerebrate rabbit preparation (Ryan et al. 2002).

However, in a complex structure such as the larynx,

gross dissection is not always a reliable means of trac-

ing the neural pathway from extramuscular to intra-

muscular terminal branches, as the latter are very small

and hard to distinguish from blood vessels and connec-

tive tissue, even with the aid of a dissecting microscope.

Furthermore, when tracing nerve branches deeper into

the muscles they innervate, preserving one branch often

necessitates unwanted destruction of other motor

and/or sensory nerves to the same structure.

The primary aim of this study is to characterize accu-

rately the anatomical distribution of intralaryngeal

branches of the RLN so that for future studies of elec-

trophysiological terminal branches of this nerve we

could be confident of the final destination of motor

axons while recording their activity. In addition, we

sought to determine whether the branching pattern of

intramuscular nerves was consistent with compartmen-

talization of laryngeal muscles in the rabbit, as recent

evidence suggests that in both dog and human, individ-

ual laryngeal muscles (Drake et al. 1993; Sanders et al.

1993a, 1994a,b; Bryant et al. 1996) and in particular the

PCA, are organized into anatomically and functionally

distinct neuromuscular compartments. Wu & Sanders

(1992) have refined a relatively old histological tech-

nique, Sihler’s stain, to investigate intramuscular

branching of motor nerves without the problems asso-

ciated with the use of microdissection or serial histolog-

ical sections. Modified Sihler’s stain renders the whole

specimen relatively translucent while counterstaining

its nerve supply (Wu & Sanders, 1992) and has the

advantage of preserving the three-dimensional struc-

ture of the whole specimen.

Methods

Seventeen adult New Zealand White rabbits weighing

2.5–4.5 kg were killed using a lethal overdose of

sodium pentobarbitone (200 mg kg

−

1

; Sagatal, Rhone

Merieux, Ireland) administered intravenously through

a marginal ear vein. A ventral midline neck incision was

made to expose the trachea and larynx. The large veins

of the neck were divided and heparanized saline

(500 mL) was infused at 90 mmHg pressure through

cannulae inserted into both common carotid arteries.

The whole larynx, including a portion of the trachea

approximately 5 mm long, was isolated

post mortem

and prepared using a modified Sihler’s staining tech-

nique in seven stages. Reagents were obtained from

Sigma Aldrich, UK, unless otherwise stated.

1. Fixation.

The whole larynx was immersed immedi-

ately after removal in 10% unneutralized formalin for

2 weeks.

2. Maceration and de-pigmentation.

The fixed specimens

were removed from the formalin and washed in dis-

tilled water for 30 min before being placed in a solu-

tion containing 3% aqueous potassium hydroxide (KOH)

with three drops of 3% hydrogen peroxide (H

2

O

2

)

added to every 100 mL of solution. They were allowed

to incubate in this solution at room temperature. The

solution was changed every second day initially, and

at least once a week thereafter, or whenever the solution

became cloudy. Maceration continued for 3 weeks until

the tissues became translucent.

3. Decalcification.

After washing in distilled water for

30 min, the laryngeal specimens were transferred into

Sihler’s I solution for 2 weeks to decalcify the speci-

mens. Sihler’s I solution was prepared as follows: one

part glacial acetic acid, one part glycerin in six parts 1%

aqueous chloral hydrate. The specimens were trans-

ferred to fresh solution every 2–3 days.

4. Staining.

Following decalcification, each larynx was

washed in distilled water for 30 min and incubated in

Sihler’s II solution. Sihler’s II solution was prepared

using one part Ehrlich’s Haematoxylin (Lennox Labora-

tory Supplies, Ireland), one part glycerin, and six parts

1% aqueous chloral hydrate. The solution was changed

once per week. Each specimen was regularly examined

under a dissecting microscope. The staining procedure



423

was carried out for at least 3 weeks or until the large

nerves within the specimens turned dark purple and

the terminal nerve branches were well stained.

5. Destaining.

Each larynx was washed in distilled water

(30 min) then immersed in Sihler’s I solution to remove

excess stain. We found that 30 min exposure time is

adequate, with longer periods resulting in loss of fine

detail due to excessive loss of stain from fine terminal

nerve branches.

6. Clearing.

Before clearing, specimens were washed in

distilled water (30 min). Clearing involved immersing

the tissues in increasing concentrations of glycerin

(40%, 60%, 80% and 100%) in dark conditions. The

specimen remained in 40% and 60% glycerin for

2 days, and one day each in 80% and 100% glycerin.

7. Trimming.

Each specimen was divided along the

midline and the 34 hemi-laryngeal preparations were

examined under a dissecting microscope (Wild M50),

trans

-illuminated with a variable fibre-optic light

source, and carefully dissected to examine the intra-

laryngeal course of the RLN and its terminal branches. All

laryngeal muscles were dissected from their cartilagi-

nous attachments and examined as whole-mount prep-

arations. Drawings and photomicrographs were taken

during the dissecting process.

Results

Thirty-four hemi-laryngeal preparations were examined

and, of these, 28 were adequately stained. The RLN

approached the larynx as a single trunk and entered it

through a groove between the oesophagus and trachea

on the posterior tracheal surface. The intralaryngeal

neuroanatomy of the RLN revealed the following inner-

vation pattern for individual laryngeal muscles.

Pca

As the RLN entered the larynx, passing over the crico-

thyroid joint, the nerve supply of the PCA branched

medially from the main trunk (Fig. 1). In 23 of 28 PCA

specimens, one single branch arose from the main

trunk of the RLN to innervate the PCA. Upon entering

the muscle this branch subdivided into two or three

smaller intramuscular nerve branches (Fig. 2). Because

of the extensive arborization of these intramuscular

nerve branches, no clear evidence was found to

indicate any discrete compartmentalization of the

intramuscular nerve supply. In only five of the PCA

specimens examined (four of which were located on

the right-hand side of the larynx) two or three distinct

branches arose from the RLN main trunk to supply the

PCA (not shown).

Interarytenoid muscle (IA)

The nerve supply to the IA arose from the main trunk

of the RLN rostral to the branch(es) supplying the PCA

(Fig. 1). In three specimens the nerve supply to the IA

originated from the medial branch supplying the thyro-

arytenoid muscle (TA). The IA branch ran diagonally,

upwards and medially, along the anterior border of the

PCA and next to the cricoarytenoid joint before enter-

ing the inferior lateral border of the IA (Figs 1 and 2).

In 25 of 28 cases the IA branch ran as a single trunk

before dividing into two fine filaments prior to its entry

into the IA (Figs 1 and 3). However, in three of 28 laryn-

geal preparations two small filaments arose from the

RLN main trunk but quickly rejoined, continuing as a

single branch and separating into two twigs before

innervating the IA (not shown). These twigs further sub-

divided upon entering the muscle (4–5 intramuscular

nerve branches), forming a complex branching anatomy

of the intramuscular nerve branches (Fig. 3).

Lateral cricoarytenoid muscle (LCA)

After providing branches to supply the PCA and IA, the

RLN continued cranially, either as a single trunk or two

parallel divisions (medial and lateral), to the superior

border of the cricoid, where it turned sharply antero-

medially. As it approached the superior border of the

cricoid, one or two very fine twigs branched from the

RLN and travelled laterally to innervate LCA (Fig. 4).

However, in two specimens one of the two twigs sup-

plying LCA arose from the IA branch (Sanders et al.

1994a). The most consistent feature of the intramuscular

neuroanatomy of the LCA innervation was division into

2–5 smaller terminal nerve branches, which exhibited

extensive arborization throughout the muscle (Fig. 4).

TA

The remaining fibres of the RLN innervated the TA.

Two separate neuromuscular compartments were



424

identified, one supplying the pars vocalis, the other

branching extensively to supply the remainder of the

TA (Figs 5 and 6).

Communicating branches between individual

intralaryngeal nerves

Communicating twigs between individual intralaryn-

geal nerves often occurred, the most common of which

was that between the primary branch supplying the

PCA and IA (Fig. 2). Others included a communication

between terminal nerve endings supplying the TA and

IA (

n

= 2) and the IA and LCA (

n

= 2). A common com-

municating branch in one specimen between the PCA,

IA and TA muscles (Fig. 1) was also found. Except in one

preparation no evidence of any neural connection

between the intramuscular neural plexus supplying the

IA and the internal branch of the superior laryngeal

nerve (iSLN Nordland, 1930; Mu et al. 1994) was found.

Discussion

Our results clearly demonstrate that the RLN provides

separate and anatomically distinct branches to laryn-

geal abductor (PCA) and adductor muscles (TA, IA, LCA)

and verify that in the rabbit at least, it is possible to

record from branches of the RLN and be confident that

one is separately recording motor neurones destined

for abductor as opposed to adductor muscles. However,

because of the very small size of the motor nerves to the

IA and LCA it would be very difficult to record selectively

from the nerve supply to individual adductor muscles.

The distribution of intramuscular branches of the

PCA neither confirms nor rules out the possibility that

Fig. 1 Innervation of the intralaryngeal muscles by the recurrent laryngeal nerve (RLN). This photograph shows a view of the branching anatomy of the main trunk of the RLN (A) to supply the posterior cricoarytenoid muscle (B), the interarytenoid muscle (C) and the lateral cricoarytenoid (D). The muscle nerve branches supplying the thyroarytenoid proper (E) and pars vocalis (F) neuromuscular compartments of the thyroarytenoid (E) are also shown. The RLN, its terminal branches and the muscles they supply have been dissected from their respective laryngeal insertions.



425

this muscle is composed of two or three anatomically

and functionally separate compartments. In the major-

ity of specimens examined a single branch from the

RLN main trunk supplied the PCA. The intramuscular

distribution of this branch was such that it subdivided

into two or three smaller intramuscular nerve branches

whose terminal endings exhibited extensive arboriza-

tion branching irregularly throughout the muscle. We

could not distinguish separate compartments on the

basis of this branching pattern. This contrasts with

other studies in dog (Diamond et al. 1992; Drake et al.

1993; Sanders et al. 1993a) and human (Sanders et al.

1994a) PCA muscles, where the PCA was organized into

separate bellies or compartments each receiving dis-

tinct innervation from primary branches of the RLN

supplying this muscle (Diamond et al. 1992; Drake et al.

1993; Sanders et al. 1993a, 1994a). It is difficult to con-

clude with certainty whether a muscle is divided into

neuromuscular compartments based only on anatomi-

cal studies of neural branching pattern. The division of

the PCA into distinct compartments in other species is

based on a greater body of evidence, including histo-

chemical (Sanders et al. 1993a) and functional (Diamond

et al. 1992; Sanders et al. 1993a) evidence.

Fig. 2 Posterior view of the left posterior cricoarytenoid muscle (PCA). The PCA (A) has been removed and squashed to demonstrate the intramuscular branches of the PCA. In this photograph only one branch from the recurrent laryngeal nerve (RLN, E) supplying the PCA was identified. The PCA nerve bifurcates upon entering the muscle, forming three distinguishable intramuscular branches. A communicating twig (B) between the PCA (A) and the branch to the interarytenoid muscle (C), and the remainder of the RLN main trunk destined for laryngeal adductor muscles (D) are also shown.



426

A powerful yet under-utilized technique is to obtain

selective electromyographic (EMG) recordings from

different regions of the muscle. Woo & Bortoff (1987)

described different EMG responses in the medial and

lateral divisions of rat PCA during various anaesthetic

and respiratory conditions. Sanders et al. (1994b),

investigating the pattern of vocal fold motion evoked

by direct electrical stimulation of different muscle bel-

lies within the PCA, found that each belly is capable of

moving the arytenoid in different ways. We have pre-

viously shown in the rabbit that there are two distinct

types of RLN motor units with inspiratory discharge,

phasic inspiratory and tonically active units whose

activity is inhibited during inspiration (Ryan et al. 2002).

Similar populations of inspiratory motor units have

been demonstrated in the cat (Murakami & Kirchner,

1972; Sica et al. 1985). Given that the PCA is the principal

abductor of the vocal cords and is the only laryngeal

muscle innervated by the RLN that exhibits inspiratory

activities under normal conditions (Suzuki & Kirchner,

1969), it is presumed that both these inspiratory RLN

motor units innervate the PCA. A multi- or single unit

EMG recording from the PCA would determine whether

these different motor units are located in distinct

anatomical regions or compartments of the PCA.

In relation to laryngeal adductor muscles, we clearly

identified separate branches arising from the main

trunk that travelled separately to innervate the TA,

LCA and IA. The motor innervation of the IA in all cases

arose from the ipsilateral RLN alone and ran along the

rostral border of the PCA. Previous investigations on

the innervation pattern of the IA have been performed

Fig. 3 Posterior view of the right interarytenoid muscle (IA). A single nerve branch arising from the recurrent laryngeal nerve bifurcates (B) to form two small neural filaments close to its insertion into the IA (A). The intramuscular branching anatomy of these filaments forms a complex anastomatic network.



427

on specimens from human subjects. One study (Mu

et al. 1994) found that all human IA muscles studied

receive a ‘bilateral’ nerve supply from both RLNs

together with nerve twigs derived from the descending

division of the iSLN. However, Nordland (1930) found

that 18 of 19 human IA muscles were exclusively inner-

vated by the iSLN. We documented only one rabbit

hemi-laryngeal specimen where the IA received a com-

municating branch between the ipsilateral iSLN and

RLN. In all remaining laryngeal preparations each IA

received an ipsilateral nerve supply from the RLN only.

The LCA plays an important role in adducting the

vocal cords in phonation and reflex glottic closure

(Tanaka & Tanabe, 1986) but may also produce laryngeal

abduction (Stroud & Zwiefach, 1956). While these dif-

fering functions might be reflected in separation of

the LCA into functionally different neuromuscular com-

partments we and others (Sanders et al. 1993b) have

found the LCA to comprised a single neuromuscular

compartment with a homogeneous motor nerve plexus

(Sanders et al. 1993b). We found the nerve branches

supplying the LCA arose from the RLN usually as two

separate fascicles or rarely as two twigs, one from the

IA branch (Wu & Sanders, 1992; Sanders et al. 1993b)

and one from the RLN main trunk.

The TA had two distinct neuromuscular compart-

ments (Sanders et al. 1993c; Wu et al. 1994; Inagi et al.

1998), the pars vocalis and the TA proper. We did not

identify any other prominent source of or communicat-

ing anastomoses with the neural supply to the TA con-

trary to observations made in other species (Dilworth,

1921; Kambic et al. 1984; Wu et al. 1994). For instance,

the presence of communicating anastomoses between

the RLN and SLN has been demonstrated several times

in studies of the human larynx (Dilworth, 1921; Kambic

et al. 1984; Wu et al. 1994; Sanudo et al. 1999). Wu

Fig. 4 Posterior view of the right lateral cricoarytenoid muscle (LCA). The LCA (A) receives two small filaments (B), one arising from each of the two medial and lateral divisions (C) of the recurrent laryngeal nerve destined for the thyroarytenoid muscle. The intramuscular branching anatomy demonstrates 2–5 further subdivisions of the filaments innervating the muscle.



428

et al. (1994) found that the communicating nerve is

composed of fascicles that are organized into sensory

and intramuscular motor nerve branches. The sensory

component supplies the subglottic area. The intramus-

cular branch usually joined the RLN within the TA. These

investigators propose that the human communicating

nerve is ‘an extension of the external superior laryngeal

nerve that innervates the vocal cord’ connecting the

cricothyroid and TA muscles. We were unable to identify

this communicating nerve in the rabbits. The only other

mammal in which this nerve has been demonstrated

was the dog (Dedo & Ogura, 1965). The function of this

nerve may perhaps be related to vocalization or phona-

tion, functions well ascribed to the TA. Both species in

which the communicating nerve has been identified

(human and dog) produce vocal sounds. Phonation is

not, however, a well-developed function in rabbits,

and this may explain why we failed to identify a com-

municating branch in our laryngeal specimens.

In conclusion, Sihler’s stain is a powerful tool provid-

ing valuable information regarding the neuroanatomy

of the larynx. The primary benefit arising from this

study is that we now know the precise anatomical dis-

tribution of RLN branches to abductor and adductor

muscles. This will be a valuable asset when performing

future investigations to examine the respiratory role of

Fig. 5 Anteromedial view of the recurrent laryngeal nerve (RLN) branches to the thyroarytenoid (TA), lateral cricoarytenoid (LCA) and interarytenoid (IA) laryngeal adductor muscles. The adductor branches of the RLN supplying the TA and LCA approach superior to the arytenoid cartilage (E). Two or three small twigs are seen branching from the RLN to supply the LCA (C). The RLN continues to supply two larger branches (A and B) to the TA muscle. Branch A divides to diffusely innervate the TA muscle proper whereas branch B medial to the arytenoid cartilage innervates the pars vocalis. Also shown is the nerve supply to the IA muscle (D).



429

different laryngeal motor neurone pools in relation to

their known function of regulating airway patency and

expiratory airflow. However, with regard to the organ-

ization of the PCA into discrete neuromuscular com-

partments, our results using neuroanatomical tracing

techniques neither confirm nor refute their presence in

the rabbit.

References

Bartlett D, Jr, Remmers JE, Gautier H

(1973) Laryngeal regula-tion of respiratory airflow.

Resp

.

Physiol

.

18

, 194–204.

Bryant NJ, Woodson GE, Kaufman K, Rosen C, Hengesteg A,

Chen N, Yeung D

(1996) Human posterior cricoarytenoidmuscle compartments.

Anat

.

Mechanics

.

Arch

.

Otol

.

HeadNeck Surg

.

122

, 1331–1336.

Dedo HH, Ogura JH

(1965) Vocal cord electromyography in thedog.

Laryngoscope

75

, 201–211.

Diamond AJ, Goldhaber N, Wu BL, Biller H, Sanders I

(1992)The intramuscular nerve supply of the posterior cricoaryte-noid muscle of the dog.

Laryngoscope

102

, 272–276.

Dilworth TFM

(1921) The nerves of the human larynx.

J

.

Anat

.

56

, 48–52.

Drake W, Li Y, Rothschild MA, Wu B, Biller HF, Sanders I

(1993)A technique for demonstrating the entire nerve branchingof a whole muscle: Results in 10 canine posterior cricoaryte-noid muscles.

Laryngoscope

103

, 141–148.

Green JH, Nail E

(1955) The respiratory function of laryngealmuscles.

J

.

Physiol

.

129

, 134–141.

Fig. 6 Anteromedial view of the recurrent laryngeal nerve (RLN) branches to the thyroarytenoid muscle (TA). Before innervating the TA the adductor branch of the RLN bifurcates (C). One supplies the TA proper (A) dividing further into smaller intramuscular branches that extend rostrally through the TA towards the base of the epiglottis. A second branch (B) courses anteriorly and medially along the border of the arytenoid cartilage (removed) to innervate the pars vocalis.



430

Inagi K, Schultz E, Ford CN

(1998) An anatomic study of the ratlarynx: establishing the rat model for neuromuscular func-tion.

Otol

.

Head Neck Surg

.

118

, 74–81.

Insalaco G, Kuna ST, Cibella F, Villeponteaux RD

(1990)Thyroarytenoid muscle activity during hypoxia, hypercapnia,and voluntary ventilation in humans.

J

.

Appl

.

Physiol

.

69

,268–273.

Kambic V, Zargi M, Radsel Z.

(1984) Topographic anatomy ofthe external branch of the superior laryngeal nerve.

J

.

Laryngol

.

Otol

.

98

, 1121–1124.

Mu L, Sanders I, Wu BL, Biller H

(1994) The intramuscularinnervation of the human interarytenoid muscle.

Laryngo-scope

104

, 33–39.

Murakami Y, Kirchner JA

(1972) Respiratory movements of thevocal cords: an electromyographic study in the cat.

Laryngo-scope

82

, 454–467.

Nordland M

(1930) The larynx as related to surgery of thethyroid. Based on an anatomical study.

Surg

.

Gyn. Obst

.

51

,449–459.

Ryan S, McNicholas WT, O’Regan RG, Nolan P

(2002) Effectof upper airway negative pressure and lung inflation onlaryngeal motor unit activity in rabbit.

J

.

Appl

.

Physiol

.

92

,269–278.

Sanders I, Wu B, Biller HF

(1993a) The three bellies of thecanine posterior cricoarytenoid muscle: implications for under-standing laryngeal function.

Laryngoscope

103

, 171–177.

Sanders I, Mu L, Wu BL, Biller HF

(1993b) The intramuscularnerve supply of the human lateral cricoarytenoid muscle.

Acta Otolaryngol

.

113

, 679–682.

Sanders I, Wu BL, Mu L, Li Y, Biller H

(1993c) The innervationof the human larynx.

Arch

.

Otol

.

Head Neck Surg

.

119

, 934–939.

Sanders I, Jacobs Wu B, Mu L, Biller HF

(1994a) The innervationof the human posterior cricoarytenoid muscle: Evidence for

at least two neuromuscular compartments.

Laryngoscope

104

, 880–884.

Sanders I, Rao F, Biller HF

(1994b) Arytenoid motion evokedby regional electrical stimulation of the canine posteriorcricoarytenoid muscle.

Laryngoscope

104

, 456–462.

Sanudo JR, Maranillo E, Leon X, Mirapeix RM, Orus C, Quer M

(1999) An anatomical study of anastomoses between thelaryngeal nerves. Laryngoscope 109, 983–987.

Sherrey JH, Megirian D (1980) Respiratory EMG activity ofthe posterior cricoarytenoid, cricothyroid and diaphragmmuscles during sleep. Resp. Physiol. 39, 355–365.

Sica AL, Cohen MI, Donnelly DF, Zhang H (1984) Hypoglossalmotorneuron responses to pulmonary and superior laryngealafferent inputs. Resp. Physiol. 56, 339–357.

Sica AL, Cohen MI, Donnelly DF, Zhang H (1985) Responses ofrecurrent laryngeal motoneurons to changes in pulmonaryafferent inputs. Resp. Physiol. 62, 153–168.

Stroud MH, Zwiefach E (1956) Mechanism of the larynx andrecurrent nerve palsy. J. Laryngol. Otol. 70, 80–96.

Suzuki M, Kirchner JA (1969) The posterior cricoarytenoid asan inspiratory muscle. Ann. Otol. 78, 849–864.

Tanaka S, Tanabe M (1986) Glottal adjustment for regulatingvocal intensity: an experimental study. Acta Otol. 102, 315–324.

Woo P, Bortoff A (1987) Regional differences in electromyo-graphic activity of the posterior cricoarytenoid muscle in therat. Otol. Head Neck Surg. 97, 150.

Wu BL, Sanders I (1992) A technique for demonstrating thenerve supply of whole larynges. Arch. Otol. 118, 822–827.

Wu BL, Sanders I, Mu L, Biller H (1994) The human communi-cating nerve. Arch. Otol. Head Neck Surg. 120, 1321–1328.

Zhou D, Huang Q, St. John WM, Bartlett D Jr (1989) Respira-tory activities of intralaryngeal branches of the recurrentlaryngeal nerve. J. Appl. Physiol. 67, 1171–1178.

Intralaryngeal neuroanatomy of the recurrent laryngeal nerve of the rabbit

Documents

Transcript of Intralaryngeal neuroanatomy of the recurrent laryngeal nerve of the rabbit