Head and neck Flashcards
1
Q
Anterior scalene muscle
A
Description/Features:
* Key structure for the thoracic inlet as it is an important anatomical landmark * This muscle is covered by prevertebral fascia * Divides subclavian artery into three segments
Origin:
* Transverse processes of C3-C6
Insertion:
* Inner border of first rib (scalene tubercle)
Action:
* Elevates first rib (inspiration) * Adjunct in neck rotation/flexion
Relations:
* Anteriorly:
* phrenic nerve, vagus nerve * ascending cervical artery, transverse cervical artery, suprascapular artery * internal jugular vein, subclavian vein * sternocleidomastoid muscle, omohyoid muscle * clavicle * Posteriorly:
* second portion of subclavian artery (which is divided in three parts by the muscle) * spinal nerve roots that make up brachial plexus * Medially: * common carotid artery, first portion of subclavian artery, vertebral artery and vein * stellate ganglion (sympathetic ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion, located anterior to the transverse process of C7 - occurs in 80% people) * thoracic duct (left) or right lymphatic duct (right) * Laterally: * brachial plexus * third portion of subclavian artery
Nerve supply:
* Ventral rami of cervical nerves (C4, C5 and C6)
Blood supply:
* Ascending cervical artery (branch of inferior thyroid artery or thyrocervical trunk)
Variants:
* Spinal nerve roots that make up the brachial plexus may pass through anterior scalene * Subclavian artery may pass through or anterior to anterior scalene * May be supplied by the phrenic nerve
2
Q
Cervical plexus
A
Description:
* Plexus of the ventral rami of C1 to C4 cervical segments * Located laterally to the transverse processes and deep to the SCM * Between prevertebral muscles medially and vertebral muscles laterally (scalenus, levator scapulae, splenius cervicis) from lateral side * Anastomoses with the accessory nerve, hypoglossal nerve and sympathetic trunk * Branches of the cervical plexus emerge from the posterior triangle
Branches:
* Cutaneous (4 branches): * great auricular nerve: innervates skin near outer ear and EAM (C2-3) * transverse cervical nerve: innervates anterior region of neck (C2-3) * lesser occipital: innervate the skin and the scalp posterosuperior to the auricle (C2-3) * supraclavicular nerves: innervate region of supraspinatus, shoulder, and upper thoracic region (C3-4) * Muscular
* ansa cervicalis (loop formed from C1-C3)
* geniohyoid (C1), thyrohyoid (C1), sternothyroid, sternohyoid, omohyoid * Joined by CN XII * phrenic: innervates diaphragm and the pericardium (C3-C5) * segmental branches: innervates anterior and middle scalenes (C1-C4) * Two branches formed by roots of spinal nerves: * preauricular nerve (posterior roots of C2–C3) * postauricular nerve (posterior roots of C3–C4)
3
Q
Constrictors of the Pharynx
A
Description/Features/Relations:
* Superior, middle, inferior constrictor muscles * Constrictor muscles overlap each other and are arranged so that the superior one is innermost and the inferior one is outermost * Primary action is to constrict pharynx to deliver food bolus to oesophagus * Overlapping arrangement of the three constrictor muscles leaves 4 gaps in the pharyngeal musculature * superior to the superior constrictor muscle * levator veli palatini muscle, torus tubarius, ascending palatine artery pass * between superior and middle constrictor muscles * stylopharyngeus muscle, glossopharyngeal nerve (CN IX), stylohyoid ligament pass * between the middle and inferior constrictor muscles * internal laryngeal nerve, superior laryngeal artery and vein pass * inferior to the inferior constrictor muscles * recurrent laryngeal nerve, inferior laryngeal artery and vein pass into the larynx
Origin:
* Superior constrictor - pterygoid hamulus, pterygomandibular raphe * Middle constrictor - greater and lesser horns of hyoid bone * Inferior constrictor - cricoid and thyroid cartilage
Insertion:
* Superior constrictor - pharyngeal raphe * Middle constrictor - pharyngeal raphe * Inferior constrictor - pharyngeal raphe
Action:
* Constriction of the pharynx, facilitating swallowing
Nerve supply:
* Pharyngeal plexus formed by the vagus (CN X) nerve
Blood supply:
* Ascending pharyngeal * Tonsillar (branch of the facial artery) * Greater Palatine and Pharyngeal (branches of maxillary artery) * Lingual * Superior and Inferior Laryngeal Arteries
Venous drainage:
* Pharyngeal plexus (formed on the middle constrictor) and draining into the IJV
Lymph drainage:
* Retropharyngeal lymph nodes to the upper or lower deep cervical nodes
4
Q
External Carotid artery
A
Description:
* External carotid artery is a major artery of the head and neck * Supplies neck, face and base of skull
Origin:
* Bifurcation of the common carotid (level of C4)
Course:
* Begins at the level of the upper border of the thyroid cartilage (level of C4) * Slightly curved course upwards and anteriorly before inclining backwards to the space behind the neck of the mandible * Along its course, it rapidly diminishes in size and as it does so, gives of various branches * As it enters the parotid gland, it gives rise to its terminal branches * Lies deep to facial nerve and retromandibular vein within the parotid
Branches:
* Some Anatomists Like Freaking Out Poor Medical Students
* superior thyroid artery * ascending pharyngeal artery * lingual artery * facial artery * occipital artery * posterior auricular artery * maxillary artery (terminal branch) * superficial temporal artery (terminal branch)
Relations:
* Anteriorly (ie. ECA is crossed by these structures)
* upper root of ansa cervicalis * hypoglossal nerve (CN XII) * posterior belly of digastric muscle * stylohyoid muscle and ligament * facial nerve (CN VII) (within the parotid gland) * Passing between ECA and ICA
* pharyngeal branch of vagus nerve (CN X) * glossopharyngeal nerve (CN IX) * stylopharyngeus muscle * styloglossus muscle * Posteriorly (ie. ECA lies on these structures)
* pharyngeal wall * superior laryngeal branch of vagus nerve (CN X) * deep lobe of the parotid gland
Variants:
* Variations in level of bifurcation * Variant branching pattern include * linguofacial trunk (incidence ~20%): common origin lingual and facial arteries * thyrolingual trunk (incidence ~2.5%): common origin superior thyroid and lingual arteries * thyrolinguofacial trunk (incidence ~2.5%): common origin superior thyroid, lingual and facial arteries * common occopito-auricular trunk (incidence ~12.5%): common origin occipital and posterior auricular arteries
5
Q
External Jugular Vein
A
Description/Features:
* Drains the head, face and part of the pectoral region
Origin:
* Posterior auricular vein and posterior division of the retromandibular vein unite to form the EJV at the angle of the mandible * anterior division of the retromandibular vein drains into the facial vein and subsequently the IJV
Course/Relations:
* Courses inferiorly in the subcutaneous anterolateral neck * Deep to platysma but superficial to the SCM * Pierces the deep cervical fascia posterior to the clavicular head of the SCM * Drain into the subclavian vein
Tributaries:
*
PAST
* Posterior external jugular vein * Anterior jugular vein * Suprascapular vein * Transverse cervical vein
6
Q
Extraocular muscles
A
Description/Features:
* Six muscles that control eye movement and one muscle that controls eyelid elevation * Located in the conal space of the orbit
Origin & Insertion:
*
Superior rectus - Annulus of Zinn and Eye (anterior superior surface)
*
Superior oblique - Sup/med to Annulus of Zinn
*
Medial rectus - Annulus of Zinn and Eye (anterior medical surface)
*
Lateral rectus - Annulus of Zinn and Eye (anterior lateral surface)
*
Inferior oblique - Maxilla and Eye (posterior inferior lateral surface)
*
Inferior rectus - Annulus of Zinn and Eye (anterior inferior surface)
*
Levator palpebrae superioris - Sphenoid bone and tarsal plate of upper eyelid
Action:
* Superior rectus - Elevation * Superior oblique - Intorsion + depression with eye adducted * Medial rectus - Adduction * Lateral rectus - Abduction * Inferior oblique - Extorsion + elevation with eye adducted * Inferior rectus - Depression * Levator palpebrae superioris - Retracts and Elevates eyelid
Nerve supply:
* Superior rectus - Occulomotor nerve (superior branch) * Superior oblique - Trochlear nerve * Medial rectus - Occulomotor nerve (inferior branch) * Lateral rectus - Abducens nerve * Inferior oblique - Occulomotor nerve (inferior branch) * Inferior rectus - Occulomotor nerve (inferior branch) * Levator palpebrae superioris - Occulomotor nerve + sympathetics
Arterial supply:
*
Primarily form opthalmic artery and branches
*
Lacrimal artery (branch of opthalmic artery) supplies lateral rectus
*
Inferior oblique and interior rectus receive branches of the infraorbital artery
Venous
- Sup opthalmic vein -> cavernous sinus
- Inf opthalmic vein -> pterygoid plexus -> Emmisary veins to cavernous sinus AND joint superficial temporal vein to become retromandoibular vein
Relations
- Discuss inside/out of common tendon
- List extraconal/conal/globe/ Optic sheath spaces
7
Q
Facial Nerve
A
Description/Features:
* Seventh cranial nerve * Motor nerve to facial expression * Also has taste and parasympathetic fibres * Facial nerve nucleus in the pons
Origin/Course/Relations:
* 6 segments * segments mnemonic: I Like Going To Makeup Parties * intracranial segment * labyrinthine segment (internal auditory canal to geniculate ganglion) - 3 branches * genu * tympanic segment (from geniculate ganglion to pyramidal eminence) * mastoid segment (from pyramidal eminence to stylomastoid foramen) - 3 branches * parotid / extracranial segment (from stylomastoid foramen to post parotid branches) - 5 branches * Intracranial * emerges from the lateral pontomedullary junction and courses anterolaterally through the pontine cistern to the internal auditory canal * Labyrinthine * in the canal the facial lies antero-superiorly * superior and inferior parts of the vestibular nerve take the posterior segments of the canal * cochlear nerve runs antero-inferiorly * Bill bar divides the superior compartment of the internal acoustic meatus into an anterior and posterior compartment * falciform crest divides IAM into superior and inferior parts * enters the Fallopian canal, passing anterolaterally between and superior to the cochlea (anterior) and vestibule (posterior) * Fallopian canal = bony canal through which the facial nerve traverses the petrous temporal bone, from the internal acoustic meatus to the stylomastoid foramen * then runs back posteriorly at the geniculate ganglion (where the nervus intermedius joins the facial nerve) * three branches originate:
* greater petrosal nerve: passes forward from the geniculate ganglion to the middle cranial fossa; unites with the deep petrosal nerve and passes to the pterygoid canal to become the nerve of the pterygoid canal (Vidian nerve) * lesser petrosal nerve * external petrosal nerve * Tympanic
* passes posteriorly from the geniculate ganglion between the lateral semicircular canal prominence and promontary * immediately beneath the lateral semicircular canal in the medial wall of the middle ear cavity * at the pyramidal eminence, the facial nerve turns inferiorly * Mastoid * facial nerve descends within the mastoid, exits at the stylomastoid foramen * branches * nerve to stapedius: arises around pyramidal eminence * chorda tympani: crosses medial to malleolar handle and joins lingual nerve (branch of CNV3) to supply the anterior 2/3 of the tongue * nerve from the auricular branch of the vagus nerve (CN X): pain fibers to the posterior part of the external acoustic meatus * Extracranial
* nerve exits the stylomastoid foramen * gives off posterior auricular nerve * passes between the posterior belly of the digastric muscle and the stylohyoid muscle and enters the parotid gland (also gives nerves off to these muscles) * lying between the deep and superficial lobes of the gland the nerve divides into to main branches at the pes anserinus * mnemonic: Two Zebras Bit My Cock off
* temporal * zygomatic * buccal * mandibular (marginal) * cervical
Function:
* Motor control to most of the muscles of facial expression * also innervates the posterior belly of the digastric, the stylohyoid, and the stapedius muscle of the middle ear * Taste sensations from the anterior two-thirds of the tongue via the chorda tympani * Parasympathetic fibers to the submandibular gland and sublingual glands via chorda tympani
Arterial Supply:
* The facial nerve receives its arterial supply from three main sources: * labyrinthine artery: a branch of the AICA * superficial petrosal artery: a branch of the MMA which passes retrogradely along the greater superficial petrosal nerve * stylomastoid artery: a branch of the occipital artery which pases retrogradely into the stylomastoid foramen
Variants:
* Many branching patterns of extracranial facial nerve
8
Q
Infratemporal Fossa
A
Contents:
Boundaries: * Medial: lateral pterygoid plate * Lateral: ramus of the mandible * Anterior: infratemporal surface of the maxillary sinus * Posterior: articular tubercle of the temporal bone * Floor: medial pterygoid muscle * Roof: greater wing of sphenoid
* Muscles
* medial pterygoid * lateral pterygoid * temporalis * Arteries
* maxillary artery * MMA * buccal * inferior alveolar * deep temporal * Veins
* pterygoid venous plexus * retromandibular vein * Nerves
* mandibular nerve (V3) * inferior alveolar nerve * lingual nerve * buccal nerve * chorda tympani nerve * otic ganglion
9
Q
Internal Jugular Vein
A
Description/Features:
* Major venous return from the brain, upper face and neck
Origin:
* Formed by the sigmoid sinus and the inferior petrosal sinus in or just distal to the jugular foramen
Course/Relations:
* Formed by the union of inferior petrosal and sigmoid dural venous sinuses * Descends in the carotid sheath with the internal carotid artery * Vagus nerve (CN X) lies between the two * Receiving tributaries (Mnemonic: Medical Schools Like Confident People) * Descends into the thorax usually between the heads of the sternocleidomastoid muscle * Unites with the subclavian vein to form the brachiocephalic vein just posterior to the sternoclavicular joint
Tributaries:
* Middle thyroid vein * Superior thyroid vein * Lingual vein * Common facial vein * Pharyngeal veins * Thoracic duct on the left side and the right lymphatic duct on the right side open into the angle of union of the internal jugular and subclavian veins
Relations: * Surrounded by accompanying jugular lymph nodes * Relation to internal carotid artery
* C2 - posteriorly * C3 - posterolaterally * C4 - laterally * Vagus nerve (CN X) always situated between the ICA and IJV * Anteriorly (ie. is crossed by these structures)
* upper third - spinal root of accessory nerve (CN XI) * middle third- lower root of ansa cervicalis * lower third - SCM, tendon of omohyoid * Posteriorly (from superior to inferior as the IJV descends in the neck)
* lateral mass of C1 (atlas) * middle scalene muscle * anterior scalene muscle * pleura of lung apices
10
Q
Larynx
A
Description/Features:
* The larynx is the entrance to the airway * It is situated between the root of the tongue and trachea * Parts: epiglottis, supraglottis, glottis, subglottis * Larynx houses the vocal cords which is essential for phonation * Protects the trachea against food aspiration * The cavity is divided into three parts by mucosal folds: * false cords divide the upper (vestibule) and middle portion (ventricle) of the larynx * true cords divides the middle (ventricle) from the subglottis
Relations: * Posterior: C3 to C6 * Anterior: strap muscles of the neck * Lateral: carotid space (CCA, IJV, vagus)
Cartilages:
* The framework of the larynx is formed by cartilage: three single and three paired * Thyroid Cartilage: Largest cartilage of the larynx. It consists of two lamina, the anterior borders of which are fused. The vocal cords are attached to inner surface of the thyroid cartilage near its lower margin. * Cricoid Cartilage: Smaller. And forms the lower and posterior parts of the wall of the larynx. It consists of two parts: a posterior quadrate lamina, and a narrow anterior arch. * Epiglottis: Thin lamella of fibrocartilage projecting obliquely upward behind the root of the tongue. It is attached via the thyroepiglottic ligament to the thyroid cartilage and the hyoid bone by the hyoepiglottic ligament. * Arytenoid Cartilages: Paired cartilages. Situated at the upper border of the lamina of the cricoid cartilage, at the back of the larynx. Each is pyramidal in shape. Mucosal folds pass from the epiglottis to the arytenoid cartilages (aryepiglottic folds). * Two further paired cartilages lie within the aryepiglottic folds: the corniculate cartilages on top of the arytenoids and cuneiform cartilages immediately lateral in the free margin of the fold. * Vestibular fold (false vocal cords) attach just superior to the true vocal cords (thyroid cartilage to the arytenoid cartilage)
Arterial supply:
* Above Vocal Cords - Superior Laryngeal Artery (Branch of Superior Thyroid) * Below Vocal Cords - Inferior Laryngeal Artery (Branch of Inferior Thyroid)
Venous drainage:
* Above Vocal Cords - Superior Laryngeal Veins to the Superior Thyroid Veins * Below Vocal Cords - Inferior Laryngeal Veins to the Inferior Thyroid Veins
Nerve supply:
* Motor:
* Recurrent Laryngeal Nerve * Except Cricothyroid muscle which is supplied by External Laryngeal Nerve (branch of the Superior Laryngeal) * Sensory:
* Above Vocal Cords - Internal Laryngeal Nerve (branch of the Superior Laryngeal) * Below Vocal Cords - Recurrent Laryngeal Nerve
Lymphatic drainage:
* Deep Cervical Nodes
11
Q
Lymph Nodes in the neck
A
Level I: Submental and submandibular nodes
Level Ia: Submental triangle
Level Ib: Submandibular triangle
Level II: Upper jugular nodes
Level III: Middle jugular nodes
Level IV: Lower jugular nodes
Level V: Posterior triangle group
Level Va: Superior posterior triangle group
Level Vb: Inferior posterior triangle group
Level VI: Anterior triangle group
Level VII: Upper mediastinal nodes
Anterior triangle borders:
Mandible, anterior margin of SCM, midline from chin to jugular notch on manubrium
Posterior triangle borders:
Anterior margin of trapezius, posterior margin of SCM, clavicle
12
Q
Mandible
A
Description/Features:
* The mandible forms the jaw * It consists of two halves united at the symphysis menti * Each half has a horizontal body and vertical ramus
Body:
* External surface:
* midline ridge indicating the symphysis * mental foramen: inferior to second premolar tooth, allows for the passage of the mental vessels and mental nerve * Internal surface:
* mental spines: origin of geniohyoid * fossas for the submental and submandibular salivary glands * mylohyoid groove * Superior (or alveolar) border
* attachment of buccinator muscle * Inferior border * groove for the facial artery
Ramus:
* External surface * attachment to the masseter muscle * Inner surface * mandibular foramen: inferior alveolar vessels and nerve pass into the mandibular canal * mandibular canal runs obliquely downward in the ramus, and then horizontally forward in the body and communicates with alveoli via the incisive nerves through small openings * lingula mandible: prominent, sharp ridge in front of the mandibular foramen, and attachment for the sphenomandibular ligament * Lower border
* covered by the parotid gland * angle of the mandible is at its junction of the posterior border and the body * medial pterygoid inserts into the angle of the mandible * Anterior border
* continuous with the oblique line * Upper border * consists of the coronoid process (anterior) and the condylar process (posterior), separated by the mandibular notch
Coronoid Process
*
Separated from the condylar process by the mandibular notch
*
Temporalis muscle insert into its medial and lateral surfaces
*
Masseter muscle also inserts to its lateral surface
Condylar Process
*
Consists of two portions - condyle and neck
*
Articulates with the articular disk of the TMJ, in the mandibular fossa of the temporal bone
*
Lateral pterygoid muscle inserts into condylar neck
Arterial supply:
* Facial artery (branch of external carotid artery) * Lingual artery (branch of external carotid artery) * Inferior alveolar artery (branch of maxillary artery)
Variants:
* The mental foramen may be doubled or tripled * The mylohyoid groove may be bridged over by a bony process and converted into a canal * Anomalous teeth distributed throughout the mandible
13
Q
Maxillary Artery
A
First (mandibular) part:
Five branches, each of which enters a bony foramen:
deep auricular artery (enters squamotympanic fissure)
anterior tympanic artery (enters squamotympanic fissure)
middle meningeal artery (enters foramen spinosum)
accessory meningeal artery (enters foramen ovale)
inferior alveolar artery (enters mandibular foramen)
- branch is artery to mylohyoid
Second (pterygoid or muscular) part:
Five branches although pterygoid branches are irregular in their number and origin:
anterior deep temporal branches posterior deep temporal branches pterygoid branches masseteric artery buccinator artery
Third (pterygopalatine) part:
Six branches including the terminal branch:
posterior superior alveolar artery
infraorbital artery (enters inferior orbital fissure)
artery of the pterygoid canal
pharyngeal artery (enters palatovaginal canal)
greater (descending) palatine artery (enters greater palatine foramen)
sphenopalatine artery - terminal branch (enters sphenopalatine foramen)
Mnemonic:
DAM I AM Piss Drunk But Stupid Drunk I Prefer, AP
14
Q
Middle ear ossicles
A
Description:
* There are three ossicles (from lateral to medial):
* malleus * incus * stapes * Mechanically amplify the vibrations of the tympanic membrane and transmit them to the cochlea * Reside in the middle ear cavity and articulate with each other via tiny synovial joints
Malleus:
* Malleus has a head, neck, and three distinct processes (handle, anterior and lateral processes) * Head is oval in shape, and articulates posteriorly with the incus * Neck is the narrow contracted part just beneath the head * Handle (manubrium) is connected by its lateral margin with the tympanic membrane * Anterior process is directed towards the petrotympanic fissure * Lateral process attaches to the upper part of the tympanic membrane
Incus:
* Articulating with the malleus laterally and the stapes medially * Its parts include: * body which articulates with the head of the malleus * superior ligament of the incus attaches body to the roof of the middle ear cavity * long crus down to the lentiform process (lenticular process) which articulates with the stapes * short crus to which the posterior ligament of the incus is attached
Stapes:
* Smallest of the ossicles * Has a base (foot piece / footplate) which seals the oval window and conducts vibrations to the cochlea * Base is attached to the neck via an anterior and posterior arch (aka anterior and posterior crura) * On top of the neck is a concave head which articulates with the lentiform nodule (lenticular process) of the incus * The stapes has a number of attachments:
* incostapedial joint (a synovial joint) * annular ligament around the oval window * stapedeus (muscle attaches to the back of the neck)
15
Q
Nasal Cavity
A
Description/Features:
* The nasal cavity is formed by: * anteriorly: nasal aperture * laterally: inferior, middle and superior nasal conchae or turbinates * superiorly: cribiform plate of the ethmoid bone * inferiorly: palatal processes of the maxilla and horizontal portion of the palatine bone * In the midline, the nasal cavity is divided into right and left halves by a septum composed of fibrocartilage, the vomer and the perpindicular plate of the ethmoid bone * Anteriorly it is continuous with the nose at the nasal aperture * Posteriorly it is continuous with the nasopharynx * Laterally, the three nasal conchae form three spaces:
* superior meatus * middle meatus * inferior meatus
Relations:
*
Superior meatus communicates with the posterior ethmoidal air cells and sphenoid sinuses via the spheno-ethmoidal recess
*
Middle meatus communicates with the frontal sinus via frontal recess, and the ethmoid and maxillary sinuses via the ostiomeatal complex
*
Inferior meatus communicates with nasolacrimal duct
Arterial supply: * The arterial supply of the nasal cavity is rich and derives from both the internal and external carotid arteries (mnemonic: GASPS) * Lateral nasal wall
* anterior and posterior ethmoidal arteries (branch of the opthalmic artery) * sphenopalatine artery (branch of the maxillary artery) * pharyngeal artery (branch of the ascending pharyngeal artery) * Septum * greater palatine artery (branch of the maxillary artery) * sphenopalatine artery (branch of the maxillary artery ) * anterior and posterior ethmoid branches (branch of the opthalmic artery ) * Floor * greater palatine artery (branch of the maxillary artery) * superior labial arteries * Rich arterial supply results in two anastomotic areas, which are common sites of epistaxis: * Woodruff area: anastomosis of sphenopalatine and pharyngeal arteries just posterior to the inferior turbinate * Kiesselbach plexus: anastomosis of the anterior ethmoid, greater palatine, sphenopalatine and superior labial arteries in the anteroinferior nasal septum
Venous drainage:
* Venous plexus drains into the sphenopalatine vein, facial vein, infraorbital veins, ophthalmic veins * Note that posterior ethmoid veins anastomose with veins of the dura mater and orbit (making this a potential route of spread of infection)
Innervation:
* CN V2: mucous membrane of the nasal septum * CN I: olfactory by the olfactory nerve
Lymphatic drainage:
* Submandibular, retropharyngeal and deep cervical lymph nodes
