Test 2 Flashcards
Bones of the roof of the orbit
Orbital plate of frontal bone
Lesser wing of sphenoid
Bones of the lateral wall of the orbit
Frontal process of zygomatic
zygomatic process of frontal
Greater wing of sphenoid
Bones of the floor of the orbit
Maxilla (orbital surface)
Palatine (orbital process)
Zygomatic (orbital plate)
Bones of the medial wall of the orbit
Maxilla (frontal process)
Lacrimal
Ethmoid (orbital plate)
Lesser wing of sphenoid
What are the margins of the orbit?
Supraorbital margin (frontal bone)
Infraorbital margin (maxilla and zygomatic)
Foramen, grooves and fissures of the orbit
Supraorbital foramen
Infraorbital groove
Optic foramen
Superior orbital fissure
Inferior orbital fissure
Nasolacrimal fossa
Infraorbital groove
Travels into infraorbital canal where it exits as infraorbital foramen
Infraorbital nerve, arteries and veins travel through it
What goes through the superior orbital fissure?
Oculomotor
Trochlear
Branches of opthalamic division of trigeminal
Abducens
Sympathetic roots of ciliary ganglion
Inferior orbital fissure
Separates greater wing of sphenoid from palatine, maxilla and zygomatic bones
Nasolacrimal fossa
Deep concavity within lacrimal bone that harbours lacrimal sac which drains tears into inferior meatus of nose
Three layers of the wall of the eyeball
- Fibrous layer (outer)
- Vascular layer (middle)
- Retina (inner)
Parts of the fibrous layer of the eyeball
- Sclera: white opaque coat of dense collagenous CT that gives eye shape, protects internal parts and is an attachment site for extraocular eye muscles
- Cornea: avascular, transparent; superficial to iris and allows light to enter
Scleral venous sinus (canal of Schlem)
A channel at the junction of cornea and sclera for drainage of aqueous fluid
Parts of the vascular layer of the eyeball
- Choroid: posterior, dark brown portion that lines internal surface of sclera; blood supply nourishes retina and melanin absorbs stray light rays
- Ciliary body: dark brown anterior portion; consists of ciliary processes and ciliary muscles
- Iris: coloured portion btwn cornea and retina
Ciliary processes
Part of ciliary body of vascular layer of eyeball; folds on inner surface that secrete aqueous humour and attach zonular fibres to the lens
Ciliary muscles
Part of ciliary body of vascular layer of eyeball; smooth muscle tissue encircling the lens that allow adaption to near or far sighted vision via contracting and relaxing
Smooth muscle layers of iris
- Spinchter pupillae muscles (circulare muscles): constrict pupil vis parasympathetic function
- Dilator pupillae (radial muscles): dilate pupil via sympathetic function (superior cervical ganglion)
**regulate light entering eyeball
Optic disc
Site of exit of optic nerve; central retinal vein and artery bundled w it
Two major portions of the retina
- Pigmented layer: contains melanin which helps choroid absorb stray light rays
- Inner neural(sensory) layer: contains photoreceptors
Three layers of retinal neurons in neural layer
- Photoreceptor cell layer: contains rods and cones
- Bipolar cell layer: horizontal and amacrine cells that modify signals from photoreceptors to bipolar ganglion cells
- Ganglion cell layer: contains optic nerve axons
Rods and Cones
Rods: vision of shades of grey; periphery
Cones: colour vision in bright light; in fovea centralis
Macula
Centre of retina; contains fovea centralis
Fovea centralis
small depression in macula containing cones; area of highest visual resolution (sharpness of vision)
Lens
Clear, transparent, avascular, refractive bioconvex disc structure located posterior to iris and pupil
Two cavities of the eye divided by the lens
- Anterior segment
- btwn cornea and lens
-anterior and posterior chamber
-filled w aqueous humour that nourishes cornea and lens and produces intraocular pressure that maintains shape of eyeball - Posterior segment
-filled w jelly like vitreous body that contributes to intraocular pressure to maintain shape and protects retina against choroid
How is aqueous humour produced?
By ciliary bodies and drained into scleral venous sinuses
Hyaloid canal
Channel travelling through vitreous body from optic disc to posterior aspects of lens
Intrinsic eye muscles
Sphincter pupillae
Dilator pupillae
Extrinsic eye muscles
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Superior oblique
Inferior oblique
Levator palpabrae superioris
Structures of the anterior segment of the eyeball
Cornea
Anterior cavity (chambers)
Iris
Lens
Ciliary body (ciliary muscles, ciliary processes, suspensory ligaments of lens- zonular fibres)
Superior rectus
Elevates and adducts
N: oculomotor
Inferior rectus
Depresses and adducts
N: oculomotor
Lateral rectus
Abducts
N: Abducens
Medial rectus
Adducts
N: oculomotor
Superior oblique
depresses and abducts
N: trochlear
Inferior oblique
Elevates and abducts
N: oculomotor
Levator palpebrae superioris
Elevates upper eyelid
N: oculomotor
Lacrimal apparatus- The Flow of Tears
- Lacrimal glands secrete tears
- Excretory lacrimal ducts distribute tears over surface of eye
- Superior and Inferior lacrimal canaliculi drain tears into
- Lacrimal sac drains tears into
- Nasolacrimal duct drains tears into
- Nasal cavity (inferior meatus)
Three main regions of the ear
i. external (outer) ear
ii. middle ear
iii. internal (inner) ear, where the mechanoreceptors for hearing and equilibrium are located
External ear function
Collects sound waves and channels them inward
External ear parts
- Auricle
- External acoustic meatus
- Tympanic membrane
Auricle (pinna)
Flap of elastic cartilage covered by skin; rim is helix and inferior portion is lobule
External acoustic meatus (ear canal)
Curved tube (2.5 cm) in temporal bone
Tympanic membrane (ear drum)
Thin wall of dense CT btwn external acoustic meatus and middle ear
Cerumen (earwax)
Secreted by ceruminous glands to prevent dust and foreign objects from entering the ear, along w tiny hairs
Function of the middle ear
Small air-filled cavity in the petrous portion of the temporal bone that is lined w epithelium
How is the middle ear separated from the external ear?
Tympanic membrane
How is the middle ear separated from the internal ear?
Vestibular window and Cochlear window
Auditory ossicles
Located in tympanic cavity (middle ear)
1. Malleus: attached to internal surface of tympanic membrane
2. Incus: articulated w head of stapes
3. Stapes: attached to oval window
Muscles attached to the ossicles, their innervation and action
- Tensor Tympani: attaches to malleus
- N: mandibular division of trigeminal - Stapedius muscle: attaches to stapes
- N: facial
- Action of both: prevent damage to inner ear
Eustachian tube
Connects middle ear to nasopahrynx; made of bone and elastic cartilage and functions to equalize the air pressure on both sides of the tympanic membrane so that it may vibrate freely
Two main divisions of the Inner ear (labyrinth)
- Outer bony labyrinth
- Inner membranous labyrinth
What is the bony labyrinth?
A series of cavities in inner ear lined with periosteum and filled w perilymph in the petrous portion of the temporal bone divided into three areas:
1. Semicircular canals
2. Vestibule
3. Cochlea
Perilymph (periotic fluid)
Fills bony labyrinth
Membranous labyrinth
Series of interconnected sacs and tubes inside the bony labyrinth; lined w epithelium and filled with endolymph (otic fluid)
Three main parts
1. Semicircular ducts
2. Utricle
3. Saccule
Utricle and succule
Located in vestibule; interconnected sacs of membranous labyrinth
Semicircular canals
Anterior, posterior and lateral semicircular canals
Made of bone
Semicircular ducts
Located within semicircular canals; communicate w the utricle of the vestibule
Vestibular ganglia
Contains axons of the sensory neuron cell bodies of the vestibulocochlear nerve
Cochlea bony channels
- Separated by cochlear duct
1. Scala vestibuli: ends at vestibular window
2. Scala tympani: ends at cochlear window
**filled with perilymph
Vestibular membrane
Separates cochlear duct from scala vestibuli
Basilar membrane
Separates cochlear duct from scala tympani
Spiral organ (organ of corti)
- Coiled sheet of epithelial and supporting cells resting on basilar membrane
- Contains inner and outer hair cells which act as receptors for hearing
Tectorial membrane
On the hair cells
Parts of the external nose
- Bony framework (frontal bone, nasal bones, maxillae)
- Nasal septum
- Upper and lower lateral cartilage
- Minor and major alar cartilage
Parts of the nasal septum
- Perpendicular plate of the ethmoid
- Septal nasal cartilage
- Vomer
Boundaries of the nasal cavity
Roof – houses the cribriform plate
Floor – hard palate
Medial wall – nasal septum
Lateral Wall – houses the conchae and meatuses
Two regions of the internal nose (nasal cavity)
- Respiratory region (inferior)
- Olfactory region (superior)
Function of the internal nose
- Incoming air is warmed, moistened, and filtered
- olfactory stimuli are detected
- large, hollow resonating chambers modify speech sounds by vibrations
Blood supply of the nasal cavity
- maxillary artery
- opthalamic artery
- blood drains into the facial, and ophthalmic veins
Apertures of the nasal cavity
Anterior - nostrils
Posterior - nasopharynx (choana)
Superior - cribriform plate
Inferior - Incisive canal
Posterosuperior - sphenopalatine foramen
Respiratory region of nasal cavity
- Superior, middle, and inferior nasal concha
- Inferior nasal meatus, middle nasal meatus, superior nasal meatus and the sphenoethmoidal recess (drains sphenoid sinus)
Olfactory region of the nasal cavity
- Cribriform plate
- Olfactory epithelium and receptors
Nasal vestibule
Nasal hair
Innervation of the nasal cavity
Olfactory (I) nerve
Ophthalmic and maxillary branches of the trigeminal (V) nerve
Openings of the paranasal sinuses
- Superior meatus: opening of posterior ethmoidal sinus
- Middle meatus: openings of frontal, maxillary and anterior and middle ethmoidal sinuses
-Inferior meatus: opening of nasolarimal duct - Sphenoethmodial recess: opening of sphenoid sinus
Anatomy of the mouth
- cheeks
- lips (labia)
- oral cavity
- palate (soft and hard)
Labial frenulum
Mucous membrane that attaches inner surface of each lip to its corresponding gum
Oral cavity
- space extending from lips to fauces
Two components of oral cavity
- Oral vestibule: space btwn external cheeks and lips and the internal gums and teeth
- Oral cavity proper: space extending from gums and teeth to the fauces that connects oral cavity to oropharynx
Palate
- separates oral cavity from nasal cavity
Hard palate
- anterior 2/3 of roof of mouth
- palatine process of maxilla and perpendicular plates of palatine bones covered by a mucous membrane
Soft palate
- posterior portion of roof of mouth
- btwn nasopharynx and oropharynx
- finger like process called uvula
- during swallowing uvula and soft palate move superiorly preventing food from entering nasopharynx
Two muscular folds lateral to the uvula
- Palatoglossal arch: anterior; extends to side of the base of the tongue
- Palatopharyngeal arch: posterior; extends to side of pharynx
Tonsils and their location
- Palatine tonsils: btwn the two arches
- Lingual tonsils: base of tongue
Minor salivary glands
-labial
-buccal
-palatal
-lingual
-Function: secrete small amounts of saliva to keep mouth and pharynx moist
Major salivary glands
- secrete major quantities of saliva when food enters mouth
- parotid glands
- submandibular glands
- sublingual glands
Borders of the parotid gland
- Superior: zygomatic arch
- Anterior: masseter muscle
- Posterior: sternocleidomastoid muscle
Lobes of the parotid gland
- superficial lobe: extends anteriorly
- deep lobe: retromandibular fossa
Parotid (Stensen’s) duct
- projects from the anterior portion of the superficial lobe and runs over the masseter muscle
-pierces buccinator muscle and opens into vestibule of mouth
How does the facial nerve course through the parotid gland?
- divides into five facial branches
How does the facial nerve course through the parotid gland?
- divides into five facial branches
Parasympathetic innervation to the parotid gland
- Glossopharyngeal nerve
- preganglionic fibres synapse in otic ganglion
- produces secretion of saliva
Sympathetic innervation to parotid gland
- superior cervical ganglion
- vasoconstriction
Submandibular glands location
- base of tongue
- posterior portion of submandibular triangle
Lobes of the submandibular glands
- superficial lobe: deep to cervical fascia
- deep
- separated by mylohyoid muscle
What surrounds the submandibular gland?
- a capsule which is part of the superficial layer of the deep cervical fascia
The submandibular (Wharton’s) ducts
- travel anteriorly
- open into the oral cavity on either side of the lingual frenulum
Parasympathetic innervation of the submandibular glands
- receives input from chorda tympani nerve, a branch of the facial nerve coming from the submandibular ganglion
-Function: secretomotor capacity
Sympathetic innervation of the submandibular glands
- cell bodies in superior cervical ganglion
Sublingual glands location
- floor of the mouth superior to the submandibular glands and resting on the mylohyoid muscle
- lies btwn the muscles of the floor of the oral cavity
- mandible borders them laterally
Minor sublingual (Rivinus’) ducts
- open into the floor of the mouth in the oral cavity proper
Sublingual duct of Bartholin
- largest sublingual gland excretory duct
- joins Wharton’s duct near the sublingual caruncle
Sublingual caruncle
- a papilla located medial to the sublingual gland and lateral to the lingual frenulum
Parasympathetic innervation of sublingual glands
- chorda tympani nerve
Blood supply of the major glands
- branches of the external carotid, facial, or lingual arteries
- blood drains into tributaries of the external jugular, facial, sublingual, and submental veins.
Chemical stimulation of taste bud receptors
- result in nerve impulses being transmitted to superior and inferior salivary nuclei in brainstem
The tongue
- an accessory digestive structure composed of skeletal muscle covered with mucous membrane
- forms floor of oral cavity
Median septum
- divides tongue into symmetrical lateral halves
What is the tongue attached to?
- hyoid bone, styloid process of temporal bone and mandible
Extrinsic muscles of the tongue function
move the tongue as a whole (i.e., gross movement for food manipulation during chewing and swallowing, hold the tongue in position, and assist in speech)
Extrinsic muscles of the tongue
- genioglossus
- hyoglossus
-styloglossus
-palatoglossus
Genioglossus muscle
A triangular muscle which protrudes and depresses the tongue
- N: hypoglossal
Hyoglossus muscle
A thin muscle, which depresses the tongue
- N: hypoglossal
Styloglossus muscle
Draws the tongue upwards and backwards and divide the tongue into two parts (longitudinal and oblique).
- N: hypoglossal
Palatoglossus muscle
Elevates the root of tongue and closes off the oropharynx
- N: vagus nerve via pharyngeal plexus
Intrinsic muscles of the tongue function
contained within the tongue itself and alter its size and shape to produce fine movements for talking and swallowing
Intrinsic muscles of the tongue
- Superior longitudinal muscle
- Inferior longitudinal muscle
- Vertical muscle of the tongue
- Transverse muscle of the tongue
Superior longitudinal muscle
makes the tongue concave and together with the inferior longitudinal muscle, shortens the tongue
Inferior longitudinal muscle
- makes the tongue convex
Vertical muscle of the tongue
flattens and widens the tongue
Transverse muscle of the tongue
narrows and elongates the tongue
Lingual frenulum
Fold of mucous membrane that attaches the midline of the inferior surface of the tongue to the floor of the mouth; it limits movement of the tongue posteriorly
Lingual papillae
- projections of the lamina propria covered with stratified squamous epithelium that contain taste buds (with the exception of the filiform papillae)
-located on superior and lateral surfaces of tongue
Fungiform papillae
- mushroom-like elevations distributed among the filiform papillae
- more numerous near the margin of the tongue
- appear as red dots due to numerous capillaries
- most of them contain taste buds
Vallate papillae
- arranged in an inverted V-shape on the posterior surface of the tongue
- all of them contain taste buds which are mostly innervated by the glossopharyngeal nerve (CN IX)
Foliate papillae
- lateral margins of tongue
- few taste buds
Filiform papillae
- pointed, threadlike projections distributed in parallel rows over the anterior two-thirds of the tongue
- lack tastebuds but contain touch receptors
- give tongue a white colour and increase friction between the tongue and food, making it easier for the tongue to manipulate food
Teeth
accessory digestive organs located in dental alveoli (sockets) of the alveolar processes of the mandible and maxillae
Gingivae
- gums
- extend slightly into each socket to form the gingival sulcus
Periodontium
- connective tissue that lines dental alveoli
- anchors teeth in position and acts as a shock absorber during chewing
Periodontal ligament
- fibres attaching tooth to bone
Three regions of a tooth
- Crown: visible portion located above the level of the gums
- Roots: 1-3 embedded in each dental alveolus
- Neck: narrow junction of the crown and root near the gum line
Dentin
- calcified connective tissue that makes up the majority of the tooth
- gives the tooth its shape and rigidity
Dental tubules
- parallel microscopic tubules that have processes called odontoblasts (cells that produce dentin) and fluid
- exposure of these tubules to air elicits dentin hypersensitivity and pain.
Cement
- bonelike substance that attaches the root to the periodontal ligament
Pulp cavity
enclosed by dentin and is filled with dental pulp, which consists of connective tissue containing blood vessels, lymphatic vessels, and nerves
Root canals
narrow extensions of the pulp cavity that travel through the root
Apical foramen
- opening at base of each root canal
- blood vessels, lymphatic vessels, and nerves enter the tooth
Enamel
- the hardest substance in the body
- made of calcium salts
- produced as a secretion during development and cannot be replaced
- protects the tooth against the wear of chewing and is a barrier against acids that may easily dissolve the dentin
Blood supply to the pulp cavity and periodontal ligament
- anterior and posterior alveolar branches of the maxillary arteries
- incisive and dental branches of the inferior alveolar arteries
Innervation to the teeth
- sensory fibres from branches of the maxillary and mandibular divisions of the trigeminal (V) nerves
Deciduous teeth
- baby teeth
- lost btwn age 6-12
Permanent teeth
- 32
- appear btwn age 6 and adulthood
Each row contains - two central incisors
- two lateral incisors
- two canines
- two first premolars (bicuspids)
- two second premolars (bicuspids) replace the deciduous second molars
- two first permanent molars erupt at age 6
- two second permanent molars erupt at age 12
- two third permanent molars (wisdom teeth) erupt after age 17; may become impacted
Pharynx
- funnel-shaped tube composed of skeletal muscle covered by mucous membrane
- extends from the choanae to the esophagus posteriorly and the larynx anteriorly
- consists of the nasopharynx, oropharynx, and laryngopharynx
Nasopharynx
- respiratory structure
Oropharynx and laryngopharynx
- respiratory and digestive functions
- contract to propel bolus of food into the esophagus then into the stomach
Muscles of the pharynx
Three pharyngeal constrictors (superior, middle, inferior)
- N: pharyngeal plexus (CN IX and X= glossopharyngeal and vagus)
-stylopharyngeus
-palatopharyngeus
Superior pharyngeal constrictor
O: Pterygomandibular raphe, posterior end of mylohyoid line of mandible, pterygoid hamulus
I: Pharyngeal tubercle (occipital bone), pharyngeal raphe
N: Vagus
A: Constriction
Middle pharyngeal constrictor
O: Greater and lesser horn of hyoid bone and stylohyoid ligament
I: Pharyngeal raphe, blends with superior and inferior constrictors
N: Vagus
A: Constriction
Inferior pharyngeal constrictor
O:Oblique line of thyroid cartilage (thyropharyngeal part) and cricoid cartilage (cricopharyngeal part)
I: Pharyngeal raphe, blends with circular esophageal fibers (cricopharyngeal part)
N: Vagus
A: Constrictor
Stylopharyngeus
O: Styloid process
I: Blends with pharyngeal constrictors, lateral glossoepiglottic fold, posterior border of thyroid cartilage
N: Glossopharyngeal
A: Elevates pharynx and larynx
Palatopharyngeus
O: Posterior border of hard palate, palatine aponeurosis
I: Posterior border of thyroid cartilage, blends with contralateral palatopharyngeus muscle
N: Branches of pharyngeal plexus (CN X)
A: Elevates pharynx superiorly, anteriorly, and medially (shortening it to swallow)
Salpingopharyngeus
O: Inferior/cartilaginous part of auditory (Eustachian) tube
I: Blends with palatopharyngeus muscle
N: Branches of pharyngeal plexus (CN X)
A: Elevates pharynx, opens auditory tube during swallowing
Pharyngeal raphe
Where the thyropharyngeal and cricopharyngeal parts of the inferior constrictor muscle come together in the midline
Larynx (voice box)
- short passageway that extends from the laryngopharynx to the trachea
- lies anterior to C4–C6.
Laryngeal vestibule
portion of the cavity above the vocal folds
Infraglottic cavity
portion of the cavity below the vocal folds
Nine pieces of cartilage of the wall of the larynx
- thyroid cartilage
- epiglottis
- cricoid cartilage
- arytenoid cartilage (2)
- corniculate cartilage (2)
- cuneiform cartilage (2)
Thyroid cartilage
- composed of two fused plates of hyaline cartilage that form the anterior and lateral walls of the larynx
- connected to the hyoid bone by the thyrohyoid membrane
Laryngeal prominence
- Adams apple
- anterior junction of two plates of hyaline cartilage
Epiglottis
large, leaf-shaped piece of elastic cartilage whose stem is attached to the internal surface of the thyroid cartilage and whose “leaf’ is unattached and can move up and down like a trap door
Glottis
- narrow passageway through the larynx made of pairs of folds of mucous membrane, vocal folds and a space between them called the Rima glottidis
- covered by the epiglottis during swallowing to prevent food and liquids from entering the Rima glottidis
Cricoid cartilage
- ring of hyaline cartilage that forms the inferior wall of the larynx
- attached to the first tracheal cartilage by the cricotracheal ligament and to the thyroid cartilage by the cricothyroid ligament
Arytenoid cartilages
- triangular pieces of mostly hyaline cartilage located at the posterior, superior border of the cricoid cartilage
- affect positions and tensions of vocal cords
Cuneiform cartilages
- club-shaped pieces of elastic cartilage located anterior to the corniculate cartilages
Formation of the structures of voice production
- mucous membrane forms vestibular folds (false vocal cords) and vocal folds (true vocal cords)
Vestibular folds
- do not function in voice production
- aid in holding breath against the pressure in the thoracic cavity
- guards rima vestibuli
Rima vestibuli
space between the vestibular folds and vocal folds
Laryngeal ventricle (sinus)
Lateral expansion of the middle portion of the laryngeal cavity btwn vestibular and vocal folds
Secretes mucus
Intrinsic muscles of the larynx
Cricothyroid
Thyroarytenoid
Lateral cricoarytenoid
Posterior cricoarytenoid
Transverse arytenoid
Oblique arytenoid
Thyroepiglottic muscle
Aryepiglottic muscle
Vocalis muscle
Cricothyroid
O: Anterolateral part of cricoid cartilage
I: Oblique part: inferior cornu of thyroid cartilage
Straight part: inferior margin of thyroid cartilage
Action: Elongates and places tension on vocal folds
N: external branch of superior laryngeal nerve (Vagus)
Lateral cricoarytenoid
Attachments
O: Superior border of cricoid cartilage
I: Anterior surface of arytenoid cartilage
A: Brings vocal folds together (adduction), thus closing the Rima glottidis
N: Recurrent laryngeal branch of Vagus (X) nerve
Posterior cricoarytenoid
O: Posterior surface of cricoid cartilage
I: Posterior surface of arytenoid cartilage
A: Moves the vocal folds apart (abduction), thus opening the Rima glottidis
N: Recurrent laryngeal branch of Vagus (X) nerve
Transverse arytenoid
O: Lateral border and muscular process of arytenoid cartilage
I: Lateral border and muscular process of opposite arytenoid cartilage
A: Adductor of vocal fold, closing the Rima glottidis
N: Recurrent laryngeal branch of Vagus (X) nerve
Oblique arytenoid
O: Muscular process of arytenoid cartilage
I: Apex of contralateral arytenoid cartilage
A: Adducts arytenoid cartilages,
Acts as a sphincter of the laryngeal inlet to prevent food from entering respiratory tract
N: Recurrent laryngeal branch of Vagus (X) nerve
Thyroepiglottic muscle
O: internal surface of thyroid cartilage
I: margin of epiglottis
A: When contracting, this muscle inferiorly displaces the epiglottis.
N: Recurrent laryngeal branch of Vagus (X) nerve
Aryepiglottis
O: apex of arytenoids
I: lateral border of epiglottis
A: Works synergistically with Thyroepiglottic muscle to close the laryngeal inlet by pulling the epiglottis posteriorly and inferiorly.
N: Recurrent laryngeal branch of Vagus (X) nerve
Vocalis muscle
O: lateral surface of vocal process of arytenoid cartilage
I: anterior part of ipsilateral vocal ligaments near thyroid cartilage
A: Assists thyroarytenoid muscles in drawing the arytenoid cartilages anteriorly allowing the vocal ligaments to shorten, thicken and relax; control and change the tonal quality of the voice
N: Recurrent laryngeal branch of Vagus (X) nerve
Blood supply of larynx
- superior and inferior laryngeal arteries
- blood drains into the superior and inferior laryngeal veins
Neck regions
- anterior and a posterior triangle, separated by the sternocleidomastoid muscle.
Anterior triangle of the neck
- stretches from the midline of the neck anteriorly
- posterior border: sternocleidomastoid
- superior border: body of the mandible
- Further subdivided into four smaller triangles: the submandibular, submental, carotid and muscular triangles
Posterior triangle
Anterior border: sternocleidomastoid muscle
Posterior border: trapezius
Inferior border: clavicle
- further subdivided by the omohyoid muscle into smaller supraclavicular and a larger occipital triangle.
Borders of the submandibular triangle (digastric triangle)
Laterally: sternocleidomastoid muscle
Superiorly: inferior border of the mandible
Medially: anterior midline of the neck
Posteriorly: the posterior belly of the digastric and stylohyoid muscles
Anteriorly: the anterior belly of digastric muscle
Roof: skin, superficial cervical fascia, the platysma, and deep cervical fascia
Floor: Mylohyoid and Hyoglossus muscles
Contents of the submandibular triangle
Submandibular glands and lymph nodes
Geniohyoid muscle
VESSELS: Facial artery and vein, Submental artery and vein, Lingual artery and deep lingual vein
NERVES: Mylohyoid nerve, Branches of the facial nerve and transverse cutaneous cervical nerves
Borders of the submental triangle
Lateral: Anterior belly of the digastric muscle
Inferior (base): Hyoid bone
Superior (apex): Mandibular symphysis
Floor: Mylohyoid muscle
Contents of the submental triangle
Submental viens
Submental lymph nodes
Borders of the muscular triangle
Superior: Hyoid bone
Superolateral: Superior belly of omohyoid muscle
Inferolateral: Sternocleidomastoid muscle
Base: Median line of the neck
Apex: Junction of the sternocleidomastoid and superior belly of the omohyoid muscles
Contents of the muscular triangle
Muscles: Infrahyoid muscles (omohyoid (superior belly), Thyrohyoid, Sternothyroid
Glands: Thyroid gland, Parathyroid gland
Vessels: Superior thyroid artery and vein, Inferior thyroid artery and vein, Anterior jugular vein
Borders of the carotid triangle
Anterior: Superior belly of the omohyoid muscle
Superior: Posterior belly of digastric muscle
Posterior: Anterior border of the sternocleidomastoid muscle
Floor: Thyrohyoid, hyoglossus, middle and inferior constrictors of the pharynx muscles
Contents of the carotid triangle
Carotid sheath containing the common carotid artery, internal jugular vein, vagus nerve, deep cervical lymph nodes
Superior thyroid artery
Lingual artery
Facial artery
Ascending pharyngeal artery
Occipital artery
Hypoglossal nerve
Accessory nerve
Ansa cervicalis
Ansa cervicalis
- a loop formed by branches of spinal nerves C1-C3 - runs through the anterior part of the carotid sheath and gives off several motor branches to the infrahyoid strap muscles
Innervation of ansa cervicalis
- Superior root (C1): supplies thyrohyoid muscle via CN XII
- Inferior root (C2-C3): supplies most of the infrahyoid muscles (omohyoid, sternohyoid and sternothyroid muscles)
Borders of the supraclavicular triangle
Superior: Inferior belly of omohyoid muscle
Anterior: Sternocleidomastoid muscle
Inferior: Clavicle
Floor: Anterior and middle scalene muscles
Contents of the supraclavicular triangle
Subclavian artery
Transverse cervical artery
Dorsal scapular artery
External jugular vein
Brachial plexus, phrenic nerve
Supraclavicular lymph nodes
Borders of the occipital triangle
Anterior: Posterior border of sternocleidomastoid muscle
Posterior: Trapezius muscle
Inferior: Inferior belly of omohyoid muscle
Floor: Levator scapulae, middle scalene and splenius capitis muscles
Contents of the occipital triangle
Occipital artery
Transverse cervical artery
Accessory nerve
Brachial plexus
Cervical plexus
Phrenic nerve
Mylohyoid nerve
branch of the inferior alveolar nerve, which arises from the mandibular branch of the trigeminal nerve
Digastric muscle
- double bellied muscle that defines the submandibular triangle
- O: anterior belly= digastric fossa
posterior belly= mastoid notch of temporal bone - I: joined by tendinous sheath and insert into hyoid bone
-N: anterior belly= mylohyoid nerve
posterior belly= facial nerve - A: depresses mandible (opens mouth)
Mylohyoid muscle
- true diaphragm of the floor of the mouth
- O: mylohyoid line on inner surface of mandible
- I: body of hyoid bone
- N: mandibular nerve via mylohyoid nerve (CN V3)
- A: Forms floor of oral cavity, elevates hyoid bone and floor of mouth, depresses mandible
Where does the common carotid artery travel?
Courses upwards along the sternocleidomastoid muscle into the carotid triangle, where it bifurcates within the carotid sheath into the internal and external carotid arteries
What is located in carotid sheath?
-internal carotid artery
-internal jugular vein
-vagus nerve
- common carotid artery
Branches of the external carotid artery that arise within carotid triangle
Superior and inferior thyroid arteries and veins
Facial artery
Superior and inferior thyroid arteries and veins
- travel through the muscular triangle
- supply the thyroid and parathyroid glands
Facial artery
Courses through the submandibular triangle together with the facial vein to supply superficial structures of the face
Pathway of the accessory nerve
enters the neck in the carotid triangle and courses beneath the sternocleidomastoid muscle to reach the occipital triangle within the posterior neck
Carotid sheath
Important landmark in head and neck anatomy and contains several vital neurovascular structures, including the carotid artery, jugular vein, vagus nerve, and sympathetic plexus
Where is the carotid sheath?
- extends upwards from the arch of the aorta and terminates at the skull base
- medially: pharynx
- laterally: parotid gland
- anteriorly: infratemporal fossa
- posteriorly: prevertebral fascia
Function of carotid sheath
- separate and help protect the vital structures within it
- facilitates the passage of intrathoracic structures through the neck to terminate in the head and face
Structures encircled by fibrous connective tissue (carotid sheath) in the neck
a. Common carotid artery
b. Internal & External carotid arteries
c.. Internal jugular vein
d.. Cranial nerves (glossopharyngeal, vagus, accessory, hypoglossal)
e. Sympathetic plexus of nerves
f. Deep cervical lymph nodes
Innervation of muscles of mastication
Mandibular branch of trigeminal
Muscles of mastication
Temporalis
Medial pterygoid muscle
Lateral pterygoid muscle
Masseter
Temporalis
O: Temporal fossa
I: Coronoid process of mandible
A: anterior fibres= Elevates mandible, posterior fibres= retract mandible
N: Deep temporal branches of mandibular nerve
Medial pterygoid muscle
Superficial head O: Maxillary tuberosity and pyramidal process of palatine
Deep head O: lateral plate of pterygoid process and pyramidal process of palatine bone
I: ramus and angle of mandible
A: protrusion, elevation, medial movement of mandible
N: Branches of mandibular division of trigeminal
Lateral pterygoid muscle
Superior head O: infratemporal crest of greater wing of sphenoid
Inferior head O: Lateral pterygoid plate
I: Mandible
A: protrusion, depression, medial movement of mandible
N: Mandibular division of trigeminal
Masseter
O: Maxillary process of temporal bone, zygomatic arch
I: Ramus and angle of mandible
A: Elevates and protrudes mandible
N: Masseteric nerve of mandibular nerve
Muscles of the mouth
Levator labii superioris
Levator labii superioris alaeque nasi
Risorius
levator anguli oris
zygomaticus major
zygomaticus minor
depressor labii inferioris
depressor anguli oris
mentalis
orbicularis oris
buccinator
Modiolus
- fibromuscular hub where muscles of mouth insert into
- located at the angles of the mouth
- formed by the buccinator, orbicularis oris, risorius, depressor anguli oris and zygomaticus major muscles
Muscle that elevate and evert the upper lip
levator labii superioris
levator labii superioris alaeque nasi
risorius
levator anguli oris
zygomaticus major and zygomaticus minor muscles
Muscles that depress and evert the lower lip
depressor labii inferioris
depressor anguli oris
mentalis muscles.
Muscle that closes the lips
Orbicularis oris
Muscle that compresses the cheek
Buccinator muscle
Innervation of the muscles of the mouth
Facial nerve
Buccinator muscle parts
Superior: originates from the alveolar process of maxilla
Inferior: originates from the buccinator ridge of mandible
Posterior: originates from pterygomandibular raphe
I: modiolus
A: compresses cheek
N: buccal branch of facial nerve
Smiling muscle
Risorius
Muscles of the eyelids
orbicularis oculi
corrugator supercilii
depressor supercilii
Attachments of the muscles of the eyelids
Orbital part of orbicularis oculi: peripheral part overlaying the orbital rim
Palpebral part: central part that comprises the eyelids
Action of orbital part of orbicularis oculi
tightly closes the eyes
Action of palpebral part
finer control of the eyelids by closing them gently during blinking or sleeping
Action of deep palpebral part of orbicularis oris
- compresses lacrimal sac
Innervation of muscles of the eyelids
Facial nerve
Nasal group muscles
Nasalis
Procerus
Nasalis muscle
- small muscle found on each side of the dorsum of the nose
- A: compressing the nasal aperture with its transverse part, and dilating the nostrils with its alar part
- N: facial
Procerus muscle
- small pyramidal muscle occupying the region of the glabella, found between the eyebrows
- A: acts on its superior attachment to depress the medial ends of the eyebrows and wrinkle the skin over the glabella
- N: facial
Muscles of the cranium and neck
Occipitofrontalis
Platysma
Occipitofrontalis muscle
O: Frontal belly = skin of the eyebrows and muscles of forehead
- Occipital belly= lateral two-thirds of the superior nuchal line of occipital bone
I: epicranial aponeurosis
N: facial
A: Frontal belly - elevates eyebrows, wrinkles forehead
Occipital belly- retracts scalp
Muscles of anterior triangle of neck: Submandibular and submental triangle
- mylohyoid
- diagastric
- stylohyoid
Platysma muscle
O: skin and fascia of the superior thoracic and shoulder regions and ascends along the anterolateral sides of the neck
I: lower border of the mandible, the modiolus, and the skin of the lower lip
A: lowering the corners of the mouth and lower lip, assisting in depressing the mandible and opening the mouth.
N: Facial
Stylohyoid
O: styloid process of temporal
I: hyoid bone
A: elevates and draws hyoid bone posteriorly
N: stylohyoid branch of facial nerve
Muscles of anterior triangle: Muscular triangle
infrahyoid strap muscles
- omohyoid
- sternohyoid
- thyrohyoid
- sternothyroid
Innervation of infrahyoid strap muscles
Ansa cervicalis (C1-C3)
- except thyrohyoid is C1 via hypoglossal nerve
Muscles of posterior triangle of neck
sternocleidomastoid (CN XI)
Trapezius (CN XI)
Omohyoid (ansa cervicalis)
Muscles of posterior triangle of neck: scalene muscles
scalene anterior, posterior and medius
Thyrohyoid
depresses hyoid bone and elevates larynx
Sternohyoid
depresses hyoid bone
Sternothyroid
depresses larynx
Omohyoid
depresses and retracts hyoid and larynx
Branches of the facial nerve
- temporal
- zygomatic
- buccal
- mandibular
- cervical
Nerves of the larynx
Vagus
- superior laryngeal nerve
- recurrent laryngeal nerve
Ligaments, folds and membranes of the larynx
Thyrohyoid membrane
Triangular membrane (cricothyroid ligament, conus elasticus)
Quadrangular membrane (aryepiglottic ligament)
Vestibular folds
Vocal folds
Suprahyoid muscle group of the neck
- diagastric
- stylohyoid
- mylohyoid
-geniohyoid
Suprahyoid muscle group of the neck (floor of mouth)
- diagastric
- stylohyoid
- mylohyoid
-geniohyoid
Geniohyoid
Elevates and draws hyoid bone anteriorly; shortens
the mouth floor; widens pharynx
N: hypoglossal nerve
Taste sensation of the tongue
Ant 2/3= facial
Post 1/3= glossopharyngeal
Epiglottis = vagus
General sensation of tongue
Ant 2/3= lingual nerve (mandibular nerve)
Post 1/3= glossopharyngeal
Epiglottis= vagus
Medial pterygoid muscle
Superficial head O: Maxillary tuberosity and pyramidal process of palatine bone