Anatomy of the neck Flashcards
Define the posterior triangle of the neck
Bounded by the posterior border of the sternocleidomastoid muscle, anterior border of the trapezius muscle and the middle third of the clavicle.
Define the anterior triangle of the neck
Bounded by the anterior border of the sternocleidomastoid muscle, the inferior border of the mandible and the midline of the neck.
What are the names of the triangles that the anterior triangle can be subdivided into?
- submandibular
- carotid
- muscular
- submental
What is the origin of the sternocleidomastoid muscle?
The sternal head originates from the manubrium
The clavicular head originates from the medial third of the clavicle
Where does the sternocleidomastoid muscle insert?
Into the mastoid process and lateral half of the superior nuchal line
Describe the innervation of the sternocleidomastoid muscle
The spinal root of cranial nerve XI and C2-3
Describe the main actions of the sternocleidomastoid muscle
Tilts head to one side i.e. laterally flexes and rotates the head so the face is turned superiorly toward the opposite side; acting together the muscles flex the neck
What is the origin of the posterior scalene muscle?
The posterior tubercles of the transverse processes of C4-C6
Where does the posterior scalene muscle insert?
2nd rib
What is the innervation of the posterior scalene muscle
C6-C8
What is the main action of the posterior scalene muscle
Flexes head laterally; elevates the second rib
What is the origin of the middle scalene muscle?
The posterior tubercles of transverse processes of C2-C7
Where does the middle scalene muscle insert?
the 1st rib
What is the main action of the middle scalene muscle
Flexes head laterally; elevates 1st rib
What is the origin of the anterior scalene muscle
Anterior tubercles of transverse processes of C3-C6
Where does the anterior scalene muscle insert?
1st rib
What is the innervation of the anterior scalene muscle
C5-C7
What is the innervation of the middle scalene muscle?
C3-C8
What is the main action of the anterior scalene muscle?
Flexes head laterally; elevates 1st rib
What is the origin of the digastric muscle?
The anterior belly originates from the digastric fossa of the mandible
The posterior belly originates from the mastoid notch
Where does the digastric muscle insert?
In the intermediate tendon to hyoid bone
What is the innervation of the digastric muscle?
The anterior belly is innervated by the mylohyoid nerve, a branch of the inferior alveolar nerve
The posterior belly is innervated by the facial nerve
What are the main actions of the digastric muscle
Depresses the mandible; raises the hyoid bone and steadies it during swallowing and speaking
What is the origin of the sternohyoid muscle?
the manubrium of the sternum and medial end of the clavicle
Where does the sternohyoid muscle insert?
In the body of the hyoid bone
What is the innervation of the sternohyoid muscle?
C1-3 from ansa cervicalis
What is the main action of the sternohyoid muscle?
Depresses the hyoid bone after swallowing
What is the origin of the sternothyroid muscle?
The posterior surface of the manubrium
Where does the sternothyroid muscle insert?
the oblique line of the thyroid lamina
What is the innervation of the sternothyroid muscle?
C2 and C3 from ansa cervicalis
What is the main action of the sternothyroid muscle?
Depresses the larynx after swallowing
What is the origin of the thyrohyoid muscle?
The oblique line of the thyroid cartilage
Where does the thyrohyoid muscle insert?
The body and greater horn of the hyoid bone
What is the innervation of the thyrohyoid muscle?
C1 via hypoglossal nerve
What is the main action of the thyrohyoid muscle?
Depresses the hyoid bone and elevates the larynx when the hyoid bone is fixed
What is the origin of the omohyoid muscle?
The superior border of the scapula near the suprascapular notch
Where does the omohyoid muscle insert?
The inferior border of the hyoid bone
What is the innervation of the omohyoid muscle?
C1-C3 from ansa cervicalis
What is the main action of the omohyoid muscle?
Depresses, retracts and fixes the hyoid bone
What is the origin of the mylohyoid muscle?
The mylohyoid line of the mandible
Where does the mylohyoid muscle insert?
In the raphe and body of the hyoid bone
What is the innervation of the mylohyoid muscle?
Mylohyoid nerve, a branch of the inferior alveolar nerve of V3
What is the main action of the mylohyoid muscle?
Elevates the hyoid bone, floor of mouth, and tongue during swallowing and speaking
What is the origin of the stylohyoid muscle?
The styloid process
Where does the stylohyoid muscle insert?
In the body of the hyoid bone
What is the innervation of the stylohyoid muscle?
The facial nerve
What is the main action of the stylohyoid muscle?
Elevates and retracts the hyoid bone
Which structures are contained in the carotid sheath?
The common carotid artery
The internal jugular vein
The vagus nerve
What are the three main fascial layers found in the neck?
The investing layer
The pretracheal layer
The prevertebral layer
What structures are surrounded by the investing fascial layer?
Surrounds the neck, and invests the trapezius and sternocleidomastoid muscles
What structures are surrounded by the pretracheal fascia layer?
(visceral) limited to the anterior neck
Invests the infrahyoid muscles, thyroid gland, trachea and oesophagus
Posteriorly called the buccopharyngeal fascia because it covers the buccinator and pharyngeal constrictor muscles
What structures are surrounded by the prevertebral layer?
Invests the prevertebral muscles and vertebral column
Includes the alar fascia anteriorly
What is the action of the suprahyoid muscles?
Raise the hyoid bone toward a stabilized mandible during swallowing
What is the action of the infrahyoid muscles?
Depress the hyoid bone and larynx during swallowing and vocalisation.
Name the suprahyoid muscles
- Digastric muscle
- Mylohyoid muscle
- Stylohyoid muscle
- Geniohyoid muscle (also extrinsic muscle of the tongue)
Name the infrahyoid muscles
- Sternohyoid muscle
- Sternothyroid muscle
- Thyrohyoid muscle
- Omohyoid muscle
What is the arterial blood supply to the neck?
The subclavian artery and some of the branches of the external carotid artery
What are the three descriptive divisions of the subclavian artery?
Part 1 - medial to the anterior scalene muscle
Part 2 - posterior to the anterior scalene muscle
Part 3 - lateral to the anterior scalene muscle
How many cervical vertebrae are there?
7
What is the normal shape of the cervical spine?
Lordosis
What structure can be found at C2-3?
The mandible
What structure can be found at level C3?
The hyoid bone
What structure can be found at level C4-5?
Thyroid cartilage
What structure can be found at level C6?
Cricoid cartilage
What structure can be found at level C7
Vertebra prominens
What is the distinguishing characteristics of C1
Ringlike bone
superior facet articulates with occipital bone
two lateral masses with facets
No body or spinous process
C1 rotates on articular facets of C2
Vertebral artery runs in groove on posterior arch
What is the distinguishing characteristics of C2
Dens projects superiorly
Strongest cervical vertebra
What is the distinguishing characteristics of C3 to C7?
Large triangular vertebral foramen
Transverse foramen, through which vertebral artery passes (except C7)
What is the distinguishing characteristic of C3 to C5?
Short bifid spinous processes
What the distinguishing characteristic of C6 to C7?
Long spinous process
What is the distinguishing feature of C7?
Vertebra prominens; nonbifid
Name the craniovertebral joints
- The atlanto-occipital
- The atlanto-axial
Both synovial
What movement does the atlanto-occipital joint facilitate?
Flexion and extension
Nodding of the head, yes
What movement does the atlanto-axial joint facillitate?
Rotation of the head side to side
Shaking of the head, no
Name the ligaments of the antalnto-occipital joint
- The articular capsule
- The anterior and posterior membranes
What is the attachments and function of the articular capsule?
Surrounds facets and occipital condyles
Allows flexion and extension
What is the attachments and function of the anterior and posterior membranes?
Anterior and posterior arches of C1 to foramen magnum
Limit of joint movement
Name the ligaments of the atlanto-axial joint
- Tectorial membrane
- Apical
- Alar
- Cruciate
What is the attachments and function of the tectorial membrane
Axis body to margin of foramen magnum
Is continuation of posterior longitudinal ligament (prevents hyperflexion)
What is the attachments and function of the apical ligament
Dens to occipital bone
Is very small
Vestigial structure
What is the attachments and function of the alar ligament?
Dens to occipital condyles
Limits rotation
What is the attachments and function of the cruciate ligament?
Dens to lateral masses
Resembles a cross
Allows rotation
Name the joints present between the vertebral arches
- Zygapophysial (plane synovial) joint
- Intervertebral (secondary cartilaginous [symphyses]) joint
What ligament is found in zygapophysial joints?
Articular capsule.
Surrounds facets and allows gliding motion.
C5-6 is most mobile.
What ligaments are found in intervertebral joints?
- Anterior longitudinal
- Posterior longitudinal
- Ligamenta flava
- Interspinous
- Supraspinous
- Ligamentum nuchae
- Intertransverse
- Intervertebral discs
What is the attachments and function of the anterior longitudinal ligament?
Anterior bodies and intervertebral discs
Is strong and prevents hyperextension
What is the attachments and function of the posterior longitudinal ligament
Posterior bodies and intervertebral discs
is weaker than AL and prevents hyperextension
What is the attachments and function of the ligamenta flava?
connects adjacent laminae of vertebrae
Limits flexion and are more elastic
What is the attachments of the interspinous ligaments?
Connect spines
What is the attachments and function of the supraspinous ligaments?
Connect spinous tips
Limits flexion
What is the attachments and function of the ligamentum nuchae?
C7 to occipital bone
Is the cervical extension of the supraspinous ligament
Limits flexion
What is the attachments of the intertransverse ligaments?
Connects transverse processes
What is the attachments and function of the intervertebral discs?
Between adjacent bodies
Are secured by AL and PL ligaments
Provides cushioning
Where is the thyroid gland found?
At the level of C5-T1, anterior to the trachea
Describe the anatomical structure of the thyroid gland
Has a right and left lobe connected by a thin isthmus
50% of patients have a pyramidal lobe that extends superiorly from the isthmus
At what level is the isthmus of the thyroid found?
Anterior to the second to fourth tracheal cartilage rings
What fascial layer surrounds the thyroid?
The visceral layer of the pretracheal fascia
Describe the blood supply and venous drainage of the thyroid gland
- Superior and inferior thyroid arteries
- Superior, middle and inferior thyroid veins
Define the larynx
A musculoligamentous and cartilaginous structure
At what level is the larynx found?
C3-C6
superior to the trachea
What is the function of the larynx
A sphincter to close off the airway
As a ‘reed’ instrument to produce sound
How many cartilage rings does the larynx contain?
9
What is the function of the intrinsic muscles of the larynx?
Adjust the tension of the vocal folds, to open or close the rima glottidis and to open or close the rima vestibuli
Name the laryngeal cartilages
- Thyroid
- Cricoid
- Epiglottis
- Arytenoid
- Corniculate
- Cuneiform
Describe the thyroid cartilage
Two hyaline laminae and laryngeal prominence (adam’s apple)
Describe the cricoid cartilage
Signet ring-shaped hyaline cartilage just inferior to thyroid
Describe the epiglottis cartilage
Spoon-shaped elastic plate attached to thyroid cartilage
Describe the arytenoid cartilage
Paired pyramidal cartilages that rotate on cricoid cartilage
Describe the corniculate cartilage
Paired cartilage that lie on the apex of arytenoid cartilage
Describe the cuneiform cartilage
Paired cartilages in ary-epiglottic folds that have no articulations
Which nerve innervates the intrinsic laryngeal muscles?
Recurrent branch of cranial nerve X, except for the cricothyroid muscle, which is innervated by the external branch of the superior laryngeal nerve (CNX)
Where is the sympathetic trunk found?
Lateral to the vertebral bodies, the entire length of the vertebral column.
What is the origin of the trapezius muscle?
The superior nuchal line, external occipital protuberence, nuchal ligament and spinous processes of C7-T12.
Where does the trapezius muscle insert?
Lateral third of the clavicle, acromion and spine of scapula
What is the innervation of the trapezius muscle?
Accessory nerve (CN XI) and C3-C4
What is the main action of the trapezius muscle?
Elevates, retracts and rotates the scapula
Lower fibers depress the scapula.
Name the branches found in part 1 of the subclavian artery
- Vertebral
- Internal thoracic
- Thyrocervical trunk
Name the branch in part 2 of the subclavian artery
Costocervical trunk
Name the branch in part 3 of the subclavian artery
Dorsal scapular
Describe the course of the vertebral branch of the subclavian artery
Ascends through C6 to C1 transverse foramena and enters the foramen magnum
Describe the course of the internal thoracic branch of the subclavian artery
Descends parasternally to anastomose with superior epigastric artery
Describe the course of the thyrocervical trunk branch of the subclavian artery
Gives rise to the inferior thyroid, transverse cervical and suprascapular arteries
Describe the course of the Costocervical trunk branch of the subclavian artery
Gives rise to the deep cervical and superior intercostal arteries
Describe the course of the dorsal scapular branch of the subclavian artery
Is inconsisitent
Which vessels drain into the subclavian vein?
Internal jugular vein, and the tributaries of the retromandibular vein and external jugular vein
What vessel does the subclavian vein drain into?
The brachiocephalic vein along with the internal jugular vein
Describe the separate areas of the brachial plexus
- 5 roots
- 3 trunks
- 6 divisions (3 anterior divisions, 3 posterior divisions)
- 3 cords
- 5 terminal branches
(remember to drink cold beer)
Where does the brachial plexus arise from?
The ventral rami of spinal nerves C5-T1
Which motor nerve branch arises from the roots of the brachial plexus?
The dorsal scapular nerve (Innervates the levator scapulae and rhomboids)
Which motor nerve branches arise from the superior trunk of the brachial plexus?
- Long thoracic nerve (innervates the serratus anterior)
- Suprascapular nerve (innervates the supraspinatus and infraspinatus)
Which motor nerve branches arise from the lateral cord of the brachial plexus?
- subclavius (innervates the subclavius)
- lateral pectoral (innervates the pectoralis major)
- musculocutaneous (innervates the anterior compartment of the arm
Which motor nerve branches arise from the medial cord of the brachial plexus?
- Medial pectoral (innervated pectoralis minor and major)
- Ulnar (innervates some forearm and hand muscles)
Which motor nerve branch arises from the medial and lateral cords of the brachial plexus?
the median nerve (innervates most of the forearm and some of the hand muscles)
Which motor nerve branches arise from the posterior cord of the brachial plexus?
- The upper subscapular (innervates the subscapularis)
- The thoracodorsal (innervates the latissimus dorsi)
- The lower subscapular (innervates the subscapularis and teres major)
- The axillary (innervates the deltoid and teres minor)
- The radial (innervates the posterior compartment muscles of the arm and forearm)
Where is the root of the neck?
Medial to the first rib
Where is the first rib in relation to the clavicle and manubrium?
Inferior moving posteriorly.
It is attached to the manubrium by the first costal cartilage
Which organ sits in the root of the neck?
The apex of the lung
Which vein is found in the root of the neck?
The subclavian vein
Which vessel is found when you follow the subclavian vein medially?
The internal jugular vein towards the midline of the neck
Which vessel is found when you follow the subclavian vein laterally?
The axillary vein - once the subclavian vein passes the first rib iferolaterally, it becomes known as the axillary vein
Where does the cervical sympathetic trunk originate from?
T1 and T2 spinal nerves
What is the stellate ganglion?
A star shaped ganglion on the neck of the first rib
Which two rami form the lower trunk of the brachial plexus?
Ventral ramus of C8 and ventral ramus of T1
What is the arterial supply to the root of the neck?
The common carotid artery branches into the subclavian artery that runs laterally to the subclavian vein
What is the brachiochephalic trunk?
Where the common carotid artery and the subclavian artery join and travel down behind the manubrium
Where does the sympathetic trunk travel?
From the base of the skull to the superior aperture of the thorax where it is continuous with the thoracic part of the trunk
What are the names of the three sympathetic ganglion found in the cervical region?
- The superior cervical sympathetic ganglia
- The middle cervical sympathetic ganglia
- The inferior cervical sympathetic ganglia
What is different about the inferior cervical sympathetic ganglia
It usually fuses with the first thoracic ganglion to form the cervicothoracic ganglion (stellate ganglion)
Name the lymph nodes found in the head and neck
- Parotid/pre-auricular nodes
- Posterior auricular/retro-auricular nodes
- Occipital nodes
- Jugulodigastric node
- Submental nodes
- Submandibular nodes
- Deep cervical nodes
- Superficial cervical nodes
- Juguloomohyoid node
- Supraclavicular nodes
Where are the parotid/pre-auricular nodes found?
In front of the ear along the surface of the parotid salivary glands (sometimes imbedded within the superficial aspect of the salivary glands)
What areas does the parotid/pre-auricular nodes drain?
The areas of the face from before the ear to the imaginary line from the inner eyelid to the mandible
Where are the posterior-auricular/retro-auricular nodes found?
Lie in the soft tissue in the area behind the ear towards the base of the skill
What areas does the posterior-auricular/retro-auricular nodes drain?
They drain the lymph from behind the ear down to the base of the skull.
Where are the submental lymph nodes found?
In the area under the chin
What areas do the submental lymph nodes drain?
Drains the tip of the tongue, the area of the lower lip and the area inside the cheek (incisor teeth)
Where are the submandibular lymph nodes?
Tucked under the mandible
What areas do the submandibular nodes drain?
They drain most of the tissues of the mouth and much of the face in addition to the nasal cavity and maxillary sinus.
Where are the occipital lymph nodes found?
Posterior skull on the occipital bone
What areas do the occipital lymph nodes drain?
The lymph from the posterior part of the skull
Where are the deep cervical nodes found?
Follow down the jugular vein
What areas do the deep cervical lymph nodes drain?
They receive lymph from the higher nodes and from many structures in the neck, such as the thyroid and larynx and the deep structures of the head
Where are the superficial cervical nodes found?
Within the posterior triangle
What areas do the superficial cervical nodes drain?
Drains lymph from structures within the posterior triangle
Where is the jugulodigastric node found?
At the junction between the digastric muscle and the internal jugular vein
What areas does the jugulodigastric node drain?
The palatine tonsils, which is why this node is phsyiologically large
Where is the juguloomohyoid node found?
At the junction of the internal jugular vein and the omohyoid muscle
What structures does the juguloomohyoid node drain?
The lingual tonsil at the posterior aspect of the tongue.
This is why this tonsil is physiologically large
Where is the supraclavicular node found?
Above the clavicle at the base of the posterior triangle
What structures do the supraclavicular nodes drain?
Drain the lymphatics from the neck but also associated to the lymphatics of the chest.
