Region 10 - Neck Flashcards
What muscle divides the neck into anterior and posterior triangles?
Sternocleidomastoid
What is the anterior boundary of the anterior triangle of the neck?
Imaginary median line of neck
What is the posterior boundary of the anterior triangle of the neck?
Anterior border of SCM
What is the superior boundary/base of the anterior triangle of the neck?
Inferior border of mandible
What is the apex of the anterior triangle of the neck?
Jugular notch at manubrium
What is the roof of the anterior triangle of the neck?
Subcutaneous tissues and platysma
What is the floor of the anterior triangle of the neck?
Pharynx
Larynx
Thyroid
What is the sub-mental division of the anterior triangle of the neck bounded by?
Chin (superiorly)
Body of hyoid (inferiorly)
Anterior bellies of digastric muscles (laterally)
Mylohyoid muscles (floor)
What is the submandibular division of the anterior triangle of the neck bounded by?
Inferior border of mandible (superiorly)
The anterior and posterior bellies of the digastric muscle
Mylohyoid and hyoglossus muscles (floor)
What are the contents of the sub-mental division?
Submental lymph nodes
Beginning of anterior jugular vein
What are the contents of the submandibular division?
Submandibular salivary gland
Lymph nodes
Facial artery and vein
Hypoglossal nerve
What are the boundaries of the carotid triangle of the anterior triangle of the neck?
Superior belly of omohyoid (anteriorly)
Posterior belly of digastric (superiorly)
Anterior border of SCM (posteriorly)
What are the contents of the carotid triangle?
Branching of common carotid into: - External carotid artery (anterior) - Internal carotid artery Branches of external carotid artery Internal jugular vein Nerves: - Hypoglossal - Accessory - Vagus Deep cervical nodes
Within what structure are the neurovascular structures contained in the carotid triangle?
Carotid sheath:
- Common and internal carotid arteries (lie medially)
- Internal jugular vein (lies laterally)
- Vagus nerve (lies posteriorly
What structures within the carotid triangle are not within the carotid sheath?
External carotid artery and its branches
Accessory nerve
Hypoglossal nerve
Deep cervical nodes
What are the boundaries of the muscular triangle of the anterior triangle of the neck?
Superior belly of omohyoid (superiorly)
Anterior border of SCM (posteriorly)
Median line of neck (anteriorly)
What are the contents of the muscular triangle?
Sternohyoid
Sternothyroid
(both form its floor)
What structures lie beneath the floor of the muscular triangle?
Thyroid
Larynx
Trachea
Oesophagus
What are the origins of platysma?
Deep fascia covering superior parts of:
- Deltoid
- Pectoralis major
Clavicle
What is the insertion of platysma?
Inferior border of mandible
What is the innervation to platysma?
Facial nerve
What are the functions of platysma?
Releases pressure on superficial veins Depresses mandible Draws corners of mouth down (frown) Facial expressions of: - Tension - Stress
What veins lie in the anterior triangle of the neck?
Tributaries to external jugular vein (superficial to SCM)
Internal jugular vein (deep to SCM)
Anterior jugular vein:
- In midline
What veins in the anterior triangle of the neck may be absent?
Anterior jugular veins
What are the main tributaries to the IJV?
Inferior petrosal sinus Facial vein Lingual vein Superior and middle thyroid veins Occipital vein (sometimes) Pharyngeal veins
What can the anterior jugular veins form superior to the manubrium?
Jugular venous arch
Where do the anterior jugular veins drain to?
External jugular vein usually
Where do the external jugular veins drain to?
Subclavian veins
What are the tributaries to the cervical plexus?
Anterior rami of C1-C4
The cervical plexus is joined by loops that lie anterior to what structures?
Levator scapulae
Middle scalene
What covers the cervical plexus?
Prevertebral layer of deep cervical fascia
What are the cutaneous sensory branches of the cervical plexus?
Lesser occipital (C2) Great auricular (C2 and C3) Transverse cervical (C2 and C3) Supraclavicular (C3 and C4)
What are the motor branches of the cervical plexus?
Ansa cervicalis (C1-C3)
Phrenic nerve (C3-C5)
Nerves to:
- Levator scapulae
Proprioception to which nerves is supplied by the cervical plexus?
SCM
Trapezius
What muscles is the ansa cervicalis branch of the cervical plexus responsible for supplying?
Sternohyoid
Sternothyroid
Omohyoid
How does the nerve supply to thyrohyoid reach the muscle?
A branch from C1 ventral ramus travels with the hypoglossal nerve
How does the branch from C1 ventral ramus reach the ansa cervicalis?
Travels initially with the hypoglossal nerve
Where is the suprahyoid region?
Between:
- Hyoid bone AND
- Skull/Mandible
Where is the infrahyoid region?
Between:
- Hyoid bone AND
- Sternum/Thyroid cartilage
What are the suprahyoid muscles?
Mylohyoid
Geniohyoid
Stylohyoid
Digastric
What are the functions of the suprahyoid muscles?
Raise hyoid bone
Depress mandible
What is the innervation to the suprahyoid muscles?
Facial nerve: - Posterior belly of digastric - Stylohyoid Mandibular division of trigeminal nerve: - Anterior belly of digastric - Mylohtoid C1 via hypoglossal nerve: - Geniohyoid
What are the infrahyoid muscles?
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
What are the functions of the infrahyoid muscles?
Depress:
- Hyoid bone
- Thyroid cartilage
What is the innervation to the infrahyoid muscles?
Ansa cervicalis: - Sternohyoid - Omohyoid - Sternothyroid C1 via hypoglossal nerve: - Thyrohyoid
What are the origins of the common carotid artery?
Right from brachiocephalic trunk
Left from arch of aorta
What are the anterior branches of the external carotid artery?
Superior thyroid artery
Lingual artery
Facial artery
What does the superior thyroid artery supply?
Thyroid gland
Infrahyoid muscles
SCM
Larynx (via superior laryngeal artery)
What does the lingual artery supply?
Posterior tongue
What are the branches of the lingual artery?
Deep lingual artery
Siblingual artery
What are the branches of the facial artery?
Ascending palatine artery
Tonsillar artery
Submental artery
How does the facial artery enter the face?
Hooks around the mid-inferior border of the mandible
What do the recurrent laryngeal branches of the vagus nerve hook around?
Left around arch of aorta
Right around right subclavian artery
What is the structure of the thyroid gland?
External capsule 2 lobes running between: - Thyroid cartilage - 6th tracheal ring Isthmus connecting lobes anterior to tracheal rings 2 or 3
What is the arterial supply to the thyroid gland?
inferior thyroid artery from thyrocervical trunk of subclavian artery
Superior thyroid artery from ECA
What is the venous drainage of thyroid gland?
Superior and middle thyroid veins:
- Drain to ipsilateral IJV
Inferior thyroid veins:
- Both drain to left brachicephalic vein
What does the submandibular salivary gland lie?
Part is inferior to mylohyoid
Part in floor of mouth superior mylohyoid
Where does the duct for each submandibular gland open?
Between 1st and 2nd lower incisors (either side of frenulum)
What is the innervation to the submandibular glands?
Facial nerve
What are the borders of the posterior triangle of the neck?
Posterior border of SCM (anterior)
Anterior border of trapezius (posterior)
Clavicle (base)
Apex:
- Where SCM and trapezius meet on superior nuchal line
Investing layer of deep cervical fascia (roof)
Muscles covered by prevertebral layer of deep cervical fascia (floor)
What are the non-muscular contents of the posterior triangle of the neck?
External jugular vein
Roots of brachial plexus
Accessory nerve
Cervical and supraclavicular lymph nodes
What are the muscular contents of the posterior triangle of the neck?
Anterior scalene (inferior part)
Middle and posterior scalenes
Splenius capitis
Levator scapulae
What are the superior attachments of the SCM?
Lateral surface of mastoid process of temporal bone
Lateral half of superior nuchal line
What are the inferior attachments of the SCM?
Sternal head:
- Anterior surface of manubrium
Clavicular head:
- Superior surface of medial 1/3 of clavicle
What is the innervation to SCM?
Motor = Spinal accessory nerve
Pain and proprioception = C2 and C3
What are the functions of SCM working unilaterally?
Flexes neck to ipsilateral side
Rotates face superiorly to contralateral side
What are the functions of SCM working bilaterally?
Extends neck at atlanto-occipital joints
Flexes cervical vertebrae
Protracts chin
What are the origins of trapezius?
Medial 1/3 of superior nuchal line
External occipital protuberance
Nuchal ligament
Spinous processes of C7-T12, lumbar and sacral vertebrae
What are the insertions of trapezius?
Lateral 1/3 of clavicle
Acromion
Spine of scapula
What is the innervation to trapezius?
Motor = Spinal accessory nerve
Pain and proprioception = C3 and C4
What are the functions of trapezius?
Ascending part = Depresses scapula Transverse part = Retracts scapula Descending part: - Elevates scapula - Rotates glenoid cavity Hold scapula in place while weightlifting
What muscles form the floor of the posterior triangle?
Omohyoid
Splenius capitis
What are the functions of splenius capitis?
Extends neck
Rotates neck
What is the innervation to splenius capitis?
Posterior rami C3 and C4
What are the origins of levator scapulae?
Transverse processes of:
- Atlas
- Axis
- C3 and C4
What are the insertions of levator scapulae?
Medial scapular border between:
- Superior angle of scapula AND
- Medial end of scapular spine
What are the functions of levator scapulae?
Controls scapular position
Elevates shoulder (with trapezius)
Can laterally flex neck ipsilaterally if shoulder fixed
What is the innervation to levator scapulae?
Cervical nerves (C3 and C4) Dorsal scapular nerve (C5)
What are the origins of the scalene muscles?
Transverse processes of:
- C3-C6 (anterior)
- C2-C7 (middle)
- C4-C6 (posterior)
What are the insertions of the scalene muscles?
Rib 1:
- Scalene tubercle (anterior)
- Behind subclavian artery groove (middle)
Rib 2 (posterior)
What is the innervation to the scalene muscles?
Anterior rami C4-C7 (anterior)
Anterior rami C3-C7 (middle)
Anterior rami C5-C7 (posterior)
What are the functions of the scalene muscles?
Flex neck (bilaterally)
Laterally flex neck (unilaterally)
Elevate upper ribs
What is the shape of the upper end of the pharynx at the base of the skull?
Funnel-shaped
At what level does the pharynx join the oesophagus?
C6
What is the epithelium of the pharynx?
Superiorly = Ciliated columnar Inferiorly = Stratified squamous
What does the fibrous layer underlying the epithelium of the pharynx connect it to?
Base of skull
Submucosa of oesophagus
What layer lies under the fibrous layer of the pharynx?
Muscular layer:
- Circular constrictor muscles
- Longitudinal muscles
Where is the nasopharynx?
Behind nasal cavities
Above soft palate
What structures form the roof of the nasopharynx?
Sphenoid bone
Occipital bone
Pharyngeal tonsil
What structure forms forms the floor of the nasopharynx?
Soft palate (pharyngeal isthmus)
What structures form the posterior wall of the nasopharynx?
Roof structures at the level of C1
What structures form the lateral wall of the nasopharynx?
Pharyngotympanic tube
Salpingopharyngeal fold
Where is the oropharynx?
From soft palate to upper border of epiglottis
What forms the roof of the oropharynx?
Soft palate
What forms the floor of the oropharynx?
Posterior 1/3 tongue
Lingual tonsil
Glossoepiglottic folds
What forms the posterior wall of the oropharynx?
C2/C3 level
What forms the lateral walls of the oropharynx?
Palatoglossal folds (anteriorly) Palatopharyngeal folds (posteriorly) Palatine tonsil between the two
Where is the laryngopharynx?
Behind larynx and laryngeal opening
What lies posterior to the laryngopharynx?
C3-C6 vertebrae
What is the laryngopharynx supported by laterally?
Thyroid cartilage
Aryepiglottic fold
Thyrohyoid membrane
What are the origins of the superior constrictor of pharynx?
Posterior aspect of medial pterygoid plate Pterygoid hamulus Pterygomandibular ligament Mandible Side of tongue
What are the insertions of the superior constrictor of pharynx?
Pharyngeal tubercle of occipital bone
Midline fibrous raphe
Middle constrictor
What is the innervation to the superior constrictor of pharynx?
CN X in pharyngeal plexus
What are the functions of the superior constrictor of pharynx?
Upper fibres:
- Pull posterior pharyngeal wall anteriorly to close off nasopharynx
Propels food to middle constrictor
What does the gap between superior and middle constrictors of pharynx allow passage of?
Stylopharyngeus
CN IX
Stylohyoid ligament
What are the origins of the middle constrictor of pharynx?
Stylohyoid ligament (lower part) Greater and lesser cornu of hyoid
What are the insertions of the middle constrictor of pharynx?
Midline fibrous raphe
Blends with superior and inferior constrictors of pharynx
What is the innervation to the middle constrictor of pharynx?
CN X in pharyngeal plexus
What is the function of the middle constrictor of pharynx?
Propels food to inferior constrictor of pharynx
What does a gap between the middle and inferior constrictors of pharynx allow the passage of?
Internal laryngeal nerve
Superior laryngeal artery and vein
What are the origins of the inferior constrictor of pharynx?
Lamina of:
- Thyroid cartilage
- Cricoid cartilage
What are the insertions of the inferior constrictor of pharynx?
Midline fibrous raph
Blends with middle constrictor and oesophagus
What is the thyropharyngeus?
The superior part of the inferior constrictor of pharynx
What direction do the fibres of thyropharyngeus run?
Obliquely
What is the innervation to thyropharyngeus?
CN X in pharyngeal plexus
What is the function of thyropharyngeus?
Propels food into oesophagus
What is the cricopharyngeus?
Inferior part of the inferior constrictor of pharynx
What direction do the fibres of cricophayngeus run in?
Transversely
What is the innervation to cricopharyngeus?
External laryngeal nerve (CN X)
What is the function of cricopharyngeus?
Acts as a sphincter:
- Prevents entry of air between acts of swallowing
What does the gap inferior to the inferior constrictor of pharynx allow passage of?
Allows passage of structures superiorly into larynx:
- Recurrent laryngeal nerve
- Inferior laryngeal artery
What is the origin and insertion of stylopharyngeus?
Origin = Styloid process Insertion = Posterior border of thyroid cartilage
What is the course of stylopharyngeus?
Runs across ICA
Passes between superior and middle constrictors
What is the function of stylopharyngeus?
Elevates larynx and pharynx during swallowing
What is the innervation to stylopharyngeus?
CN IX
What is the origin and insertion of salpingophayngeus?
Origin = Cartilage of pharyngotympanic tube Insertion = Blends with palatopharyngeus
What is the function of salpingopharyngeus?
Elevates pharynx
What is the innervation to salpingopharyngeus?
CN X in pharyngeal plexus
What are the origins of palatopharyngeus?
Hard palate
Palatin aponeurosis
What are the insertions of palatopharyngeus?
Posterior border of lamina of thyroid cartilage
Side of pharynx and oesophagus
What is the function of palatopharyngeus?
Elevates pharynx
What is the innervation of palatopharyngeus?
CN X in pharyngeal plexus
What is the ring of lymphoid tissue?
Superiorly = Pharyngeal tonsil Superolaterally = Tubal tonsils Laterally = Lymph tissue along salpingopharyngeal folds Inferolaterally = Palatine tonsils Inferiorly = Lingual tonsil
The pharyngeal plexus supplies motor fibres from CN X to all pharyngeal and soft palate muscles. What are the exceptions?
Stylopharyngeus (CN IX)
Tensor veli palatini (CN V3)
Cricopharyngeus (External laryngeal nerve = CN X)
What nerve carries sensory fibres from the pharynx?
CN IX to pharyngeal plexus
What is the arterial supply to pharynx?
Pharyngeal branches from maxillary artery - Nasopharynx
Ascending pharyngeal artery:
- From ‘deep’/medial surface of ECA
What is the venous drainage of the pharynx?
Pharyngeal veins to IJV
Where does lymph from the tonsils go?
Jugulodigastric node
Where do other pre-vertebral structures lie? (ie aside from the pre-vertebral [anterior] muscles)
Between:
- Muscle sheath covering longus colli and longus capitis (prevertebral fascia)
AND
- Carotid sheath
What are the attachments of longus capitis?
Superiorly = Occipital bone (base) Inferiorly = Anterior tubercles of C3-C6 transverse processes
What is the function of longus capitis?
Flexion of head (nodding)
What is the innervation to longus capitis?
Ventral rami of C1-C3
What are the attachments of the inferior oblique part of longus colli?
Superiorly = Anterior tubercles of C5-C6 transverse processes Inferiorly = Body of T2 and T3
What are the attachments of the superior oblique part of longus colli?
Superiorly = Anterior tubercle of C1 Inferiorly = Anterior tubercles of C3-C5 transverse processes
What are the attachments of the vertical part of longus colli?
Superiorly = Anterior aspects of C4-C6 Inferiorly = Anterior aspects of T1-T3
What is the function of longus colli?
Flexion of neck
What is the function of the inferior oblique part of longus colli?
Rotation to contralateral side
What is the innervation to longus colli?
Ventral rami of C2-C6
What are the attachments of rectus capitis anterior?
Superiorly = Occipital bone (anterior to condyles) Inferiorly = Anterior surface of and root of transverse process of C1
What is the function of rectus capitis anterior?
Flexion of atlanto-occipital joint
What is the innervation to rectus capitis anterior?
Branches from loop between C1 and C2
What are the attachments of rectus capitis lateralis?
Superiorly = Jugular process of occipital bone Inferiorly = Transverse process of C1
What is the function of rectus capitis lateralis?
Lateral flexion of head
What is the innervation to rectus capitis lateralis?
Branches from loop between C1 and C2
What structure crosses rectus capitis lateralis?
IJV
Where does the sympathetic chain lie in the neck?
Posterior to ICA and CCA Medial to CN X Embedded in deep fascia between: - Carotid sheath AND - Fascia over longus colli and longus capitis
What are the cervical ganglia of the sympathetic chain?
Superior, middle and inferior
Where does the superior cervical ganglia lie?
Immediately below skull (~C1-C2)
Where do postsynaptic fibres from the superior cervical ganglia travel to and in what?
Travel in internal carotid nerve:
- Travel into carotid canal
- Forms internal carotid plexus
What do the grey rami communicantes from the superior cervical ganglia connect to?
C1-C4 ventral rami
What branches are given off from the superior cervical ganglia?
Branches to form plexuses on CCA and ECA CN branches to CNs IX, X and XII Pharyngeal branches: - Pharyngeal plexus - Joining CNs IX and X
What cardiopulmonary splanchnic nerve is given off from the superior cervical ganglia?
Superior cardiac nerve
At what level are the middle cervical ganglia?
Cricoid cartilage (~C6)
What structure are the middle cervical ganglia related to?
Loop of inferior thyroid artery
What do the grey rami communicantes from the middle cervical ganglia connect to?
C5 and C6 ventral rami
What branches do the middle cervical ganglia give off?
Thyroid branches:
- Run along inferior thyroid artery
Middle cardiac nerve (cardiac plexus)
The middle cervical ganglia is often connected to the inferior cervical ganglia by more than 2 nerve bundles. Where does the anterior bundle pass?
Passes anterior to 1st part of subclavian artery then behind it:
- Ansa subclavia
What does the inferior cervical ganglia usually fuse with? What is this structure called?
1st thoracic ganglion = Stellate ganglion
Where do the inferior cervical ganglia lie?
Posterior to vertebral artery
Between:
- Transverse process of C7 AND
- Head of first rib
What do the grey rami communicantes from the inferior cervical ganglia connect to?
C7 and C8 ventral rami
What branches do the inferior cervical ganglia give off?
Arterial branches to:
- Subclavian artery
- Vertebral artery
Inferior cardiac nerve (to cardiac plexus)
What structures lie anterior to the larynx?
Infrahyoid muscles
Isthmus of thyroid
What structures lie lateral to the larynx?
Lobes of thyroid
Carotid sheath
What neurovascular structures is the larynx related to?
Superior and inferior thyroid arteries
Recurrent laryngeal nerves
What is the larynx responsible for?
Voice production
How many cartilages make up the larynx?
9
What type of cartilage makes up the larynx? What is the exception?
All hyaline
Except epiglottis - Elastic cartilage
What is the laryngeal prominence?
Where the inferior 2/3 of the laminae of the thyroid cartilages fuse anteriorly
What structure lies superior to the laryngeal prominence?
V-shaped superior thyroid notch
How does the thyroid cartilage connect to the hyoid?
Thyrohyoid membrane:
- Thickened medially as median thyrohyoid ligament
- Thickened laterally as lateral thyrohyoid ligament
What does an oblique line on the anterolateral surface of each thyroid cartilage act as the attachment for?
Sternothyroid muscle
Thyrohyoid muscle
Inferior constrictor of pharynx
What lies at either end of the oblique line on the anterolateral surface of each thyroid cartilage?
Superior tubercle
Inferior tubercle
Why is the cricoid cartilage described as having a signet ring shape?
Anterior part is the arch (narrower)
Posterior part is the lamina:
- Broader
- Has a central ridge
What distinguishing characteristic does the cricoid cartilage have other all other laryngeal or tracheal cartilages?
Only complete ring of cartilage to encircle any part of airways
What are the facets on the superior aspects of the posterior part of the cricoid cartilage for?
Articulation with arytenoid cartilages
What do the vocal processes on the arytenoid cartilages do?
Allow attachment of the vocal ligament
Where are the vocal processes on the arytenoid cartilages?
Anteroinferiorly
Where are the corniculate cartilages?
In posterior part of aryepiglottic folds
Attached to apices of arytenoid cartilages (superior)
Where are the cuneiform cartilages?
Within aryepiglottic folds:
- Support the folds
What are the connections of the epiglottis?
Anteriorly: - Body of hyoid - Posterior surface of thyroid cartilage Laterally: - Arytenoid cartilages (via aryepiglottic fold)
What structure does the mucous membrane covering the epiglottis reflect onto? What does this form?
Reflects onto posterior surface of tongue:
- Median glossoepiglottic fold
- Lateral glossoepiglottic folds
Where does the quadrangular membrane/ligament run?
Arytenoid cartilages to epiglottis
What do the free edges of the quadrangular membrane form?
Superiorly = Aryepiglottic fold
Inferiorly = Vestibular ligament:
- ie False vocal fold
What does the cricothyroid membrane attach to?
Cricoid cartilage
Thyroid cartilage
Arytenoid
What does the cricothyroid membrane form via its connection as its free edge to the arytenoid cartilages?
Vocal ligaments:
- ie True vocal folds
Where do the vestibular folds lie in relation to the true vocal folds?
Superiorly
What are the true vocal folds attached to?
Anteriorly = Thyroid cartilage Posteriorly = Arytenoid cartilages
Movements of what structures create individual sounds and words?
Lips
Cheeks
Tongue
How do the suprahyoid muscles affect the larynx?
Elevate larynx
How do the infrahyoid muscles affect the larynx?
Depress larynx
What assists the suprahyoid muscles in their action on the larynx?
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus
What assists the infrahyoid muscles in their action on the larynx?
Its elastic recoil
What is the origin of the cricothyroid muscle?
Anterolateral cricoid cartilage
What are the insertions of the cricothyroid muscle?
Lamina of thyroid cartilage
Inferior cornu of thyroid cartilage
What are the parts of the cricothyroid muscle?
Straight part - Lies more anteriorly
Oblique part - Lies anterolaterally
What are the functions of the cricothyroid muscle?
Tenses vocal folds
Elongates vocal folds
How does the cricothyroid muscle affect the vocal folds?
Increases distance between thyroid cartilage and vocal processes of arytenoid cartilages by:
- Tilting thyroid cartilage forwards
- Tilting cricoid cartilage backwards
What is the innervation to cricothyroid?
External laryngeal nerve (CN X)
What are the origins of the thyro-arytenoid muscle?
Inner surface of angle of thyroid cartilage
Cricothyroid ligament
What is the insertion of the thyro-arytenoid muscle?
Anterolateral surface of arytenoid cartilages
What can the upper fibres of the thyro-arytenoid muscle, which run alongside the vocal ligament, be called?
Vocalis muscle
What is the function of the thyro-arytenoid muscle?
Pull arytenoids forwards towards thyroid cartilage:
- Shortens vocal ligaments
- Relaxes vocal folds
What is the innervation to the thyro-arytenoid muscle?
Recurrent laryngeal nerve (CN X)
What is the origin and insertion of the posterior cricoarytenoid muscle?
Origin = Posterior surface of lamina of cricoid Insertion = Muscular process of arytenoid
What is the function of the posterior cricoarytenoid muscle?
Pulls muscular processes of arytenoid cartilages backwards:
- Rotates vocal processes laterally
- Vocal fold abduction
What is the innervation to the posterior cricoarytenoid muscle?
Recurrent laryngeal nerve (CN X)
What is the origin and insertion of the lateral cricoarytenoid muscle?
Origin = Upper edge of arch of cricoid cartilages Insertion = Muscular process of arytenoid cartilage
What is the function of the lateral cricoarytenoid muscle?
Pulls muscular processes forwards:
- Rotates vocal processes medially
- Vocal fold adduction
What is the innervation to the lateral cricoarytenoid muscle?
Recurrent laryngeal nerve (CN X)
What is the origin and insertion of the oblique arytenoid muscle?
Origin = Muscular process of one arytenoid cartilage Insertion = Apex of contralateral arytenoid cartilage
What do some of the fibres of the oblique arytenoid muscles form?
Aryepiglottic muscles in aryepiglottic fold
What is the function of the oblique arytenoid muscles?
Act as a sphincter of the laryngeal inlet by adducting vocal folds
What is the innervation to the oblique arytenoid muscle??
Recurrent laryngeal nerve (CN X)
What is the origin and insertion of the transverse arytenoid muscles?
Origin = Posterior and medial surfaces of arytenoid cartilages Insertion = Contralateral arytenoid cartilage
What is the function of the transverse arytenoid muscles?
Close the posterior part of rima glottidis
What is the innervation to the transverse arytenoid muscles?
Recurrent laryngeal nerve (CN X)
Where does the superior laryngeal nerve arise?
From inferior vagal ganglion at superior end of carotid triangle
Where does the superior laryngeal nerve bifurcate? What does it bifurcate into?
Within carotid sheath into:
- Internal laryngeal nerve
- External laryngeal nerve
What does the internal laryngeal nerve pierces? With what?
Thyrohyoid membrane:
- With superior laryngeal artery
What is the function of the internal laryngeal nerve?
Sensory to;
- Laryngeal mucous membrane
- Including superior surface of vocal folds
ANS fibres
What is the course of the external laryngeal nerve?
Descends posterior to sternothyroid muscle:
- With superior thyroid artery
Lies on then pierces inferior constrictor muscle
What is the function of the external laryngeal nerve?
Motor fibres to:
- Inferior constrictor
- Cricothyroid
What is the inferior laryngeal nerve a continuation of?
Recurrent laryngeal nerve
How does the inferior laryngeal nerve enter the larynx?
Passes:
- Deep to inferior border of inferior constrictor
- Medial to lamina of thyroid cartilage
What are the functions of the inferior laryngeal nerve?
Motor innervation to all intrinsic laryngeal muscles:
- Except cricothyroid
Sensory fibres to infraglottic cavity
What is the course of the superior laryngeal artery?
Branches from superior thyroid artery
Pierces thyrohyoid membrane
What does the superior laryngeal artery supply?
Internal surface of larynx
Cricothyroid muscle
What is the course of the inferior laryngeal artery?
Branches from inferior thyroid artery
Accompanies inferior laryngeal nerve
What does the inferior laryngeal artery supply?
Mucous membrane and muscles of inferior part of larynx
What is the venous drainage of the larynx?
Superior laryngeal veins: - Into superior thyroid veins - Into IJV (ipsilaterally) Inferior laryngeal veins: - Into inferior thyroid veins OR Venous plexus on trachea - Into left brachiocephalic vein
What is the lymphatic drainage of the larynx superior to the vocal folds?
Accompany superior laryngeal artery through thyrohyoid membrane
Drain to superior deep cervical nodes
What is the lymphatic drainage of the larynx inferior to the vocal fodls?
Drain to:
- Pretracheal nodes
- Paratracheal nodes
Eventualls drains to inferior deep cervical nodes
