Interval 10: Head and Neck Flashcards
The skeletal muscles of the face and scalp include muscles of _________ and __________.
- facial expression
- mastication
What nerves innervation the facial expression and mastication muscles? What are these muscles’ general functions?
- Facial expression: facial nerve (CN VII) and act as sphincters and dilators of openings on the face
- Mastication: mandibular nerve of CN V3 and act to move the mandible at the temporomandibular joint
What does TMJ stand for?
-Temporomandibular joint
The skin of the face and scalp is innervated by cutaneous branches of ____________.
-3 divisions of the trigeminal nerve and by cervical spinal nerves
What are the 3 branches of the trigeminal nerve?
V1: ophthalmic division
V2: Maxillary division
V3: Mandibular division
Branches of what 2 arteries supply the face and scalp?
- external carotid
- ophthalmic
Tributaries of what 2 veins drain the face and scalp?
-retromandibular and facial veins
The parotid gland is situated in the lateral part of the face on the surface of the ___________. A deep part of the gland extends between the ramus of the mandible and the mastoid process.
-masseter muscle
Describe the route of the parotid duct
-cross the masseter, passes through the buccinator, and opens into the oral cavity near the second upper molar
What traverses the parotid gland and what innervates it?
- traversed by muscular branches of the facial nerve, retromandibular vein, external carotid artery
- innervated by glossopharyngeal nerve
- *Note: the facial nerve DOES NOT innervate the gland, it just traverses it
The preganglionic parasympathetic fibers from the glossopharyngeal nerve synapse in the __________. The postganglionic parasympathetic fibers then travel to the parotid gland with the ___________ branch of the trigeminal nerve.
- otic ganglion
- autriculotemporal nerve
What symptoms may a parotid gland tumor cause?
-may compress the muscular branches of the facial nerve and cause weakness of muscles of facial expressions on the side of the tumor
Define trigeminal neuralgia (tic douloureux). Which branch does it usually affect?
- syndrome characterized by excruciating pain of sudden onset in the areas of distribution of one or more branches of the trigeminal nerve
- usually the maxillary nerve, the ophthalmic division is rarely involved
The most common neuralgia associated with CNV2 and CNV3 divisions of the trigeminal nerve is the type associated with ________.
-dental caries (cavities)
Is the trigeminal nerve mixed, sensory, or motor?
-mixed; large sensory root and smaller motor root
Where does the sensory root of the trigeminal nerve arise from?
- cell bodies in the trigeminal (gasserian) ganglion located in the lateral portion of the cavernous venous sinus
- it passes posteriorly under cover of the superior petrosal venous sinus and tentorium cerebelli to penetrate the pons
The sensory fibers of which division of the trigeminal nerve are joined by the motor root?
-mandibular
Describe the composition of the ophthalmic division of the trigeminal nerve
- only sensory
- supplies bulb of eye, conjunctiva, lacrimal gland; parts of nasal mucousa, paranasal sinuses, and the cutaneous areas of the forehead, eyelids, and nose
Describe the composition of the maxillary division of the trigeminal nerve
- only sensory
- supplies skin on midface and lower eyelid, side of the nose, and upper lip; mucous membrane of the nasopharnyx, maxillary sinus, soft palate, tonsil, root of mouth; maxillary teeth and gingiva
Describe the composition of the mandibular division of the trigeminal nerve
- largest of 3 divisions; mixed
- sensory:temporal area, ear, cheek, lower lip, and lowerface; mucous membrane of cheek and tongue; mastoid air cells, lower teeth and gums, mandible, TMJ, parts of cranial dura mater
- motor: muscles of mastication (masseter, temporalis, medial and lateral pterygoid), mylohyoid, anterior belly of digastric, tensor veli palatini and tensor tympani
What are the 2 compartments of the neck and where do they arise and extend?
- visceral: anterior and extends from the base of the skull to the thoracic outlet
- vertebral: posterior and extends from the foramen magnum to the thoracic outlet
What is found in the visceral compartment of the neck?
-hyoid bone, suprahyoid and infrahyoid muscles, pharynx, esophagus, larynx, and trachea
What surrounds the visceral compartment of the neck?
- pretracheal layer of deep cervical fascia encloses structures
- buccopharyngeal fascia is a continuation of the pretracheal fascia which surrounds the posterior aspect of the pharynx and esophagus
What is found within the vertebral compartment of the neck?
-cervical vertebrae, skeletal muscles that attach to cervical vertebrae, ventral rami of the cervical plexus and brachial plexus, and vertebral arteries and veins
What encloses the vertebral compartment of the neck?
-prevertebral layer of deep cervical fascia
The prevertebral layer is separated from the buccopharyngeal fascia by the ____________.
-retropharyngeal space: a potential space
Structures in the visceral compartment of the neck covered by pretracheal fascia glide against the ________________ during swallowing.
-prevertebral fascia
An infection in the retropharyngeal space may spread where?
-inferiorly into the superior mediastinum
Both compartments of the neck are partially covered by what 2 superficial muscles?
- trapezius and sternocleidomastoid
- an investing layer of deep cervical fascia encloses both compartments and splits to enclose the trapezius and the SCM
What does the superficial cervical fascia contains?
-platysma, a muscle of facial expression
What are the bounds/borders of the posterior triangle of the neck?
- trapezius
- posterior border of the SCM
- clavicle
What does the floor of the posterior triangle contain? What covers these muscles?
- anterior scalene, middle scalene, posterior scalene, levator scapulae, splenius capitis muscles
- covered by prevertebral fascia
What forms the root of the posterior triangle?
-investing layer of deep cervical fascia
Describe how the external jugular vein is formed and its trajectory
- formed by union of posterior auricular and retromandibular veins
- crosses SCM obliquely, pieces the investing fascia, and drains into the subclavian vein
The subclavian vein passes anterior to the _________________ and joins what vein to form the ____________.
- phrenic nerve and anterior scalene
- joins internal jugular vein to form a brachiocephalic vein posterior to the medial end of clavicle
What drains into the right and left brachiocephalic veins at their origins?
- right lymphatic duct into the right brachiocephalic vein
- thoracic duct into the left brachiocephalic vein
Name 3 arteries to course through the posterior triangle
- suprascapular
- transverse cervical
- occipital arteries
Where do the suprascapular and transverse cervical arteries arise from? Give their trajectory and what they supply.
- arise from the thyrocervical trunk of the subclavian
- pass anterior to the anterior scalene and phrenic nerve and cross the posterior triangle
- supply trapezius, rhomboids, levator scapulae, and muscles that attach to the posterior aspect of the scapula
Where does the occipital artery arise and what is its trajectory?
-arises from the external carotid artery and passes through the apex of the posterior triangle
Describe the composition of the accessory nerve (CN XI), where it arises, its trajectory, and what it innervates.
- skeletal motor axons arising from ventral roots of first 4-5 cervical nerves
- enters subarachnoid space and pass through the foramen magnum into the cranial cavity; it exits the skills through the jugular foramen with other nerves
- innervates SCM and trapezius
Where does the accessory nerve exit the skull and what other nerves does it exit with?
- jugular foramen
- glossopharyngeal and vagus nerves
Lesions of accessory nerve is posterior triangle and inferior to the jugular foramen
- PT: weakness in trapezius muscle; difficulty elevating scapula (shrugging shoulder) and laterally rotating scapula during abduction of arm
- JF: weakness also in SCM; decreased ability to turn the chin to the side opposite of the lesioned nerve
The phrenic nerve courses of the anterior surface of the ___________ deep to the ____________.
- anterior scalene
- deep to prevertebral fascia
The ventral rami and trunks of the brachial plexus and the subclavian artery pass between _____________.
-anterior and middle scalene muscles
Where do the cutaneous branches of the cervical plexus emerge and what is their trajectory?
- emerge posterior to the SCM approx. halfway between its sternal and mastoid attachments
- arise from VR of C1-C4 spinal nerves and pierces the investing and superficial fascia
List the 4 branches of the cutaneous branches of the cervical plexus and their segments
- Great auricular nerve (C2,C3)
- Lesser occipital nerve (C2)
- transverse cervical nerve (C2,C3)
- Supraclavicular nerves (C2, C3, C4)
What does the cutaneous branches of the cervical plexus supply?
- skin of the anterior and lateral neck including skin over the angle of the mandible
- skin of the scalp posterior to the vertex of the skull
What is the vertex of the skull?
-coronal plane through the most superior aspect of the cranium
Explain to someone how to find the tendinous insertion of the SCM
-it is palpable just lateral to the suprasternal notch
Boundaries of the anterior triangle of the neck
- SCM
- mandible
- midline of the neck
List the following structures from superior to inferior: Adam’s apple, hyoid bone, cricoid cartilage of trachea
- hyoid bone
- Adam’s apple: beginning of trachea; thyroid cartilage**
- Cricoid cartilage***
What is the movement of the trachea when swallowing?
-upward
What is a tracheotomy?
-commonly performed procedure in which an incision in made and a tube inserted through the front of the neck into the lumen of the trachea to provide an airway
2 potential sites of tracheotomy
- High trach: incision is made between cricoid cartilage and isthmus of thyroid gland
- Low trach:between 2-3 tracheal rings whith thyroid gland first being retracted upwards
TracheOSTOMY
-when a round or square opening is made in the neck rather than a slit and the tracheal mucosa brought into continuity with the skin
What must physicians be cautious of during a high vs. low tracheotomy?
- High: care not to damage thyroid gland and its extensive blood supply and the anterior jugular veins which lie on either side of the midline
- Low: more difficult due to presence of inferior thyroid venous plexus, and close proximity of pleural sacs, brachiocephalic veins, and jugular venous arch
