Podcast
Questions and Answers
The carotid sheath shares a boundary with the infratemporal fossa anteriorly.
The carotid sheath shares a boundary with the infratemporal fossa anteriorly.
True (A)
The hypoglossal nerve enters the carotid sheath by looping over the superior vagal ganglion.
The hypoglossal nerve enters the carotid sheath by looping over the superior vagal ganglion.
False (B)
The internal carotid artery and internal jugular vein are housed within the carotid sheath at the base of the skull, along with cranial nerves five through eight.
The internal carotid artery and internal jugular vein are housed within the carotid sheath at the base of the skull, along with cranial nerves five through eight.
False (B)
The cervical sympathetic trunk is situated posterior to the carotid sheath.
The cervical sympathetic trunk is situated posterior to the carotid sheath.
Signup and view all the answers
The external carotid artery reaches the base of the skull, where it divides into its terminal branches.
The external carotid artery reaches the base of the skull, where it divides into its terminal branches.
Signup and view all the answers
Inferior to the skull base, the internal jugular vein maintains a constant medial position relative to the internal carotid artery.
Inferior to the skull base, the internal jugular vein maintains a constant medial position relative to the internal carotid artery.
Signup and view all the answers
The carotid sheath originates from the aortic arch and ends at the base of the skull.
The carotid sheath originates from the aortic arch and ends at the base of the skull.
Signup and view all the answers
The glossopharyngeal and accessory nerves emerge between the internal carotid artery and internal jugular vein at the base of the skull and then diverge superficially over the vessels.
The glossopharyngeal and accessory nerves emerge between the internal carotid artery and internal jugular vein at the base of the skull and then diverge superficially over the vessels.
Signup and view all the answers
The hypoglossal canal is situated lateral and posterior to the carotid canal.
The hypoglossal canal is situated lateral and posterior to the carotid canal.
Signup and view all the answers
The vagus nerve occupies a position superficially between the internal carotid artery and internal jugular vein within the carotid sheath.
The vagus nerve occupies a position superficially between the internal carotid artery and internal jugular vein within the carotid sheath.
Signup and view all the answers
The glossopharyngeal nerve emerges from the posterior aspect of the jugular foramen medial to the inferior petrosal sinus.
The glossopharyngeal nerve emerges from the posterior aspect of the jugular foramen medial to the inferior petrosal sinus.
Signup and view all the answers
The inferior ganglion of the glossopharyngeal nerve is merely the detached lower portion of the superior ganglion.
The inferior ganglion of the glossopharyngeal nerve is merely the detached lower portion of the superior ganglion.
Signup and view all the answers
The glossopharyngeal nerve follows a course that takes it deep to stylopharyngeus.
The glossopharyngeal nerve follows a course that takes it deep to stylopharyngeus.
Signup and view all the answers
The motor branch to stylopharyngeus originates from the glossopharyngeal nerve as it passes around the muscle.
The motor branch to stylopharyngeus originates from the glossopharyngeal nerve as it passes around the muscle.
Signup and view all the answers
The carotid sinus nerve is a minor branch of the glossopharyngeal nerve with insignificant connections to autonomic centers.
The carotid sinus nerve is a minor branch of the glossopharyngeal nerve with insignificant connections to autonomic centers.
Signup and view all the answers
Pharyngeal branches of the glossopharyngeal nerve innervate the mucous membrane of the nasopharynx.
Pharyngeal branches of the glossopharyngeal nerve innervate the mucous membrane of the nasopharynx.
Signup and view all the answers
The lingual branch of the glossopharyngeal nerve exclusively provides taste sensation to the posterior third of the tongue.
The lingual branch of the glossopharyngeal nerve exclusively provides taste sensation to the posterior third of the tongue.
Signup and view all the answers
The vagus nerve exits the skull via the hypoglossal canal.
The vagus nerve exits the skull via the hypoglossal canal.
Signup and view all the answers
The inferior ganglion of the vagus nerve houses the cell bodies for the meningeal and auricular branches.
The inferior ganglion of the vagus nerve houses the cell bodies for the meningeal and auricular branches.
Signup and view all the answers
The vagus nerve descends in the neck within the carotid sheath, positioned between the common carotid artery and internal jugular vein.
The vagus nerve descends in the neck within the carotid sheath, positioned between the common carotid artery and internal jugular vein.
Signup and view all the answers
The auricular branch supplies the anterosuperior quadrant of the outer surface of the tympanic membrane.
The auricular branch supplies the anterosuperior quadrant of the outer surface of the tympanic membrane.
Signup and view all the answers
The pharyngeal branch of the vagus joins the pharyngeal plexus on the superior constrictor muscle.
The pharyngeal branch of the vagus joins the pharyngeal plexus on the superior constrictor muscle.
Signup and view all the answers
The internal laryngeal nerve pierces the thyrohyoid membrane.
The internal laryngeal nerve pierces the thyrohyoid membrane.
Signup and view all the answers
The external laryngeal nerve supplies the cricothyroid and the aryepiglottic muscles.
The external laryngeal nerve supplies the cricothyroid and the aryepiglottic muscles.
Signup and view all the answers
The left recurrent laryngeal nerve hooks around the brachiocephalic artery.
The left recurrent laryngeal nerve hooks around the brachiocephalic artery.
Signup and view all the answers
The recurrent laryngeal nerve supplies the laryngeal muscles except for the thyroarytenoid.
The recurrent laryngeal nerve supplies the laryngeal muscles except for the thyroarytenoid.
Signup and view all the answers
The accessory nerve is formed by the union of cranial and spinal roots in the anterior cranial fossa.
The accessory nerve is formed by the union of cranial and spinal roots in the anterior cranial fossa.
Signup and view all the answers
The accessory nerve passes superficial to the posterior belly of the digastric muscle.
The accessory nerve passes superficial to the posterior belly of the digastric muscle.
Signup and view all the answers
The hypoglossal nerve emerges between the external carotid artery and internal jugular vein.
The hypoglossal nerve emerges between the external carotid artery and internal jugular vein.
Signup and view all the answers
All non-lingual branches of the hypoglossal nerve are formed by C1 fibers.
All non-lingual branches of the hypoglossal nerve are formed by C1 fibers.
Signup and view all the answers
The stylopharyngeus muscle originates from the apex of the styloid process and extends inferiorly towards the larynx.
The stylopharyngeus muscle originates from the apex of the styloid process and extends inferiorly towards the larynx.
Signup and view all the answers
The external carotid artery courses superficial to the stylopharyngeus muscle but deep to the digastric and stylohyoid muscles as it enters the parotid gland.
The external carotid artery courses superficial to the stylopharyngeus muscle but deep to the digastric and stylohyoid muscles as it enters the parotid gland.
Signup and view all the answers
The hypoglossal nerve travels deep to the hyoglossus muscle, alongside the submandibular duct and the lingual artery.
The hypoglossal nerve travels deep to the hyoglossus muscle, alongside the submandibular duct and the lingual artery.
Signup and view all the answers
The styloid process exhibits considerable variability in length, mirroring the length of the stylohyoid ligament, indicative of its origin from the second pharyngeal arch cartilage.
The styloid process exhibits considerable variability in length, mirroring the length of the stylohyoid ligament, indicative of its origin from the second pharyngeal arch cartilage.
Signup and view all the answers
The stylomandibular ligament, derived from the parotid fascia's superficial lamina, connects the mandible and the tympanic part of the temporal bone.
The stylomandibular ligament, derived from the parotid fascia's superficial lamina, connects the mandible and the tympanic part of the temporal bone.
Signup and view all the answers
The styloglossus, stylopharyngeus, and stylohyoid muscles, all originating from the styloid process, each receive innervation from a distinct nerve supply.
The styloglossus, stylopharyngeus, and stylohyoid muscles, all originating from the styloid process, each receive innervation from a distinct nerve supply.
Signup and view all the answers
The retromandibular vein courses superficial to both the stylohyoid and the digastric muscles, distinct from the deeper path of the External Carotid Artery.
The retromandibular vein courses superficial to both the stylohyoid and the digastric muscles, distinct from the deeper path of the External Carotid Artery.
Signup and view all the answers
The styloid apparatus is positioned lateral to the carotid sheath, aiding the sheath's closure within the infratemporal fossa.
The styloid apparatus is positioned lateral to the carotid sheath, aiding the sheath's closure within the infratemporal fossa.
Signup and view all the answers
The glossopharyngeal nerve, stylohyoid ligament, and external carotid artery all course deep to the posterior border of the hyoglossus muscle.
The glossopharyngeal nerve, stylohyoid ligament, and external carotid artery all course deep to the posterior border of the hyoglossus muscle.
Signup and view all the answers
The stylopharyngeus, stylohyoid, and styloglossus muscles collectively contribute significantly to the action of swallowing.
The stylopharyngeus, stylohyoid, and styloglossus muscles collectively contribute significantly to the action of swallowing.
Signup and view all the answers
Flashcards
Carotid sheath
Carotid sheath
A connective tissue structure that contains the internal carotid artery, internal jugular vein, and four cranial nerves.
Location of carotid sheath
Location of carotid sheath
Extends from the arch of the aorta to the base of the skull, attaching to key bones.
Cranial nerves in carotid sheath
Cranial nerves in carotid sheath
The sheath houses the last four cranial nerves: IX (Glossopharyngeal), X (Vagus), XI (Accessory), and XII (Hypoglossal).
Internal carotid artery
Internal carotid artery
Signup and view all the flashcards
Internal jugular vein
Internal jugular vein
Signup and view all the flashcards
Vagus nerve
Vagus nerve
Signup and view all the flashcards
Glossopharyngeal nerve
Glossopharyngeal nerve
Signup and view all the flashcards
Hypoglossal nerve
Hypoglossal nerve
Signup and view all the flashcards
External carotid artery
External carotid artery
Signup and view all the flashcards
Cervical sympathetic trunk
Cervical sympathetic trunk
Signup and view all the flashcards
Common Carotid Artery
Common Carotid Artery
Signup and view all the flashcards
Stylopharyngeus
Stylopharyngeus
Signup and view all the flashcards
Tympanic Branch
Tympanic Branch
Signup and view all the flashcards
Carotid Sinus Nerve
Carotid Sinus Nerve
Signup and view all the flashcards
Pharyngeal Plexus
Pharyngeal Plexus
Signup and view all the flashcards
Superior Ganglion
Superior Ganglion
Signup and view all the flashcards
Inferior Ganglion
Inferior Ganglion
Signup and view all the flashcards
Stylohyoid Ligament
Stylohyoid Ligament
Signup and view all the flashcards
Pharyngeal branch of vagus nerve
Pharyngeal branch of vagus nerve
Signup and view all the flashcards
Superior laryngeal nerve
Superior laryngeal nerve
Signup and view all the flashcards
Occipital artery
Occipital artery
Signup and view all the flashcards
Lingual artery
Lingual artery
Signup and view all the flashcards
Geniohyoid
Geniohyoid
Signup and view all the flashcards
Mylohyoid
Mylohyoid
Signup and view all the flashcards
Auricular Branch
Auricular Branch
Signup and view all the flashcards
Pharyngeal Branch of Vagus
Pharyngeal Branch of Vagus
Signup and view all the flashcards
Recurrent Laryngeal Nerve
Recurrent Laryngeal Nerve
Signup and view all the flashcards
Accessory Nerve
Accessory Nerve
Signup and view all the flashcards
Cervical Cardiac Branches
Cervical Cardiac Branches
Signup and view all the flashcards
Cricothyroid Muscle Supply
Cricothyroid Muscle Supply
Signup and view all the flashcards
Study Notes
Carotid Sheath
- Extends from the arch of the aorta to the base of the skull.
- Attaches to the carotid canal, petrous bone, and inferior border of the tympanic part of the temporal bone.
- Contains internal carotid artery, internal jugular vein, and cranial nerves IX-XII.
- Medial to the sheath is the pharynx; laterally are the parotid gland, styloid process, and its muscles.
- Anteriorly borders the infratemporal fossa.
- Posteriorly lies the cervical sympathetic trunk on the prevertebral fascia.
- Carotid canal is in front of the jugular foramen (beneath the external acoustic meatus).
- Hypoglossal canal is medial to the carotid canal.
- Internal jugular vein is behind the internal carotid at the base of the skull, but shifts laterally as it descends.
- Vagus nerve is in the groove between the artery and vein within the carotid sheath, throughout its course.
- Glossopharyngeal and accessory nerves emerge between the artery and vein, then curve away from each other, superficial to the vessels.
- Hypoglossal nerve emerges from the hypoglossal canal, curls behind the inferior vagal ganglion, and passes between artery and vein.
Cranial Nerves (IX-XII) in Carotid Sheath
- Glossopharyngeal nerve (IX): emerges from the jugular foramen laterally to the inferior petrosal sinus.
- Inferior ganglion bulges the nerve at a notch in the petrous bone.
- Contains sensory cell bodies.
- Passes down on the internal carotid artery, curving around stylopharyngeus.
- Six branches:
- Tympanic branch (Jacobson's nerve): Supplies middle ear, mastoid air cells, auditory tube with sensory and parasympathetic fibers for parotid gland secretions.
- Motor branch to stylopharyngeus.
- Carotid sinus nerve: Main supply to carotid sinus and body (baroreceptors and chemoreceptors).
- Pharyngeal branch: Joins pharyngeal plexus, supplies oropharynx with sensation, taste, and parasympathetic fibers for glands.
- Tonsillar branch: Supplies part of tonsil, anastomoses with lesser palatine nerves.
- Lingual branch: Supplies posterior one-third of tongue with sensation and taste, and secretomotor fibers to glands.
- Vagus nerve (X): Emerges through middle compartment of jugular foramen with superior ganglion.
- Inferior ganglion below the base of the skull.
- Ganglia contain cell bodies of afferent fibers with superior ganglion (unimportant meningeal and auricular branches) and inferior ganglion (important sensory fibers).
- Inferior ganglion receives a branch from the accessory nerve.
- Supplies striated muscles of viscera (pharynx, soft palate, esophagus, larynx).
- Runs down the neck, in the back of the carotid sheath, between artery and vein.
- Branches in the neck:
- Meningeal branches.
- Auricular branch.
- Carotid body branch.
- Pharyngeal branch: joins pharyngeal plexus, supplies most pharynx and soft palate muscles (except tensor palati). -Derived from accessory nerve.
- Superior laryngeal nerve: Divides into internal and external laryngeal nerves near hyoid bone, supplying larynx.
-Internal laryngeal nerve - pierces thyrohyoid membrane to piriform recess.
- External laryngeal nerve - to cricothyroid and cricopharyngeus.
- Cervical cardiac branches.
- Recurrent laryngeal nerve.
- Accessory nerve (XI): Formed in posterior cranial fossa by union of cranial and spinal roots.
- Cranial root joins the vagus.
- Cervical fibres descend, lateral to the internal jugular vein on the atlas.
- Passes deep to the styloid process and posterior digastric, and a branch to sternocleidomastoid.
- Supplies sternocleidomastoid and trapezius muscles.
- Hypoglossal nerve (XII): Emerges from hypoglossal canal and curls forward beneath digastric, across arteries deep to veins to the tongue.
- Picks up a branch from C1.
- Supplies tongue muscles.
- No sensory fibers.
Styloid Apparatus
- Styloid process: Part of the temporal bone, remnant of the second pharyngeal arch cartilage.
- Stylohyoid ligament: Passes from the tip of the styloid process to the lesser horn of the hyoid bone.
- Three muscles (stylopharyngeus, stylohyoid, styloglossus) diverge from the styloid process, acting during swallowing.
- Styloid apparatus lies lateral to the carotid sheath.
- Stylomandibular ligament: Thickening in deep lamina of parotid fascia, extends from tympanic part of temporal bone to the angle of the mandible.
- External carotid artery runs deep to digastric and stylohyoid, but superficial to stylopharyngeus, entering the parotid gland.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores the anatomy and boundaries of the carotid sheath, including its relationship with surrounding structures like the infratemporal fossa. Understand the positions of major arteries, veins, and cranial nerves associated with the carotid sheath region at the base of the skull.
