Skin of the back of the neck and scalp innervated by
Dorsal rami of spinal nerves C2-C5
Skin of anterior and lateral aspects of neck are innervated by
Ventral rami of C2-C4 spinal nerves via cutaneous branches of cervical plexus
Where do the ventral rami of C2-C4 spinal nerves emerge from?
Underneath posterior border of sternocleidomastoid muscle
What does the ventral rami of C2-C4 spinal nerves via the cutaneous branches of the cervical plexus supply?
Skin of anterior and lateral aspects of the neck
What are the cutaneous branches of cervical plexus?
- Lesser occipital nerve (C2 or C2, C3)
- greater auricular nerve (C2, C3)
- transverse cervical nerve (C2, C3)
- supraclavicular nerves (C3, C4)
Lesser occipital nerve
- cutaneous branch of cervical plexus
- C2 or C2, C3
- follows posterior border of sternocleidomastoid
- supplies skin over lateral part of accipital region and upper part of medial surface of auricle
greater auricular nerve
- cutaneous branch of cervical plexus
- C2, C3
- ascends superficial to sternocleidomastoid, parallel to external jugular vein
- supplies skin over angle of mandible and parotid gland, and both surfaces of lower part of auricle
Transverse cervical nerve
- cutaneous branch of cervical plexus
- C2, C3
- runs anteriorly, superficial to sternocleidomastoid
- supplies skin of anterior and lateral aspects of neck
Supraclavicular nerves
- cutaneous branch of the cervical plexus
- C3, C4
- arise by a common trunk, which divides into medial, intermediate, and later supraclavicular nerves
- descend across side of lower neck
- supply skin at base of neck and skin that covers upper parts of pectoral is major and deltoid muscles
What are the medial branches of dorsal rami of cervical spinal nerves?
- greater occipital nerve (C2)
- 3rd occipital nerve (C3)
- from 4th, 5th, 6th, and 7th nerves in succession below
What is the platysma?
The muscle embedded in superficial fascia of neck
Origin of platysma
Deep fascia that covers upper parts of pectoralis major and deltoid muscles
Insertion of platysma
Fibers pass superficial to clavicle and run superiorly and medically over side of neck, some fibers insert into lower border of body of mandible, other fibers enter face and blend with muscles of lower lip and angle of mouth
Nerve supply of platysma
Cervical branch of facial nerve (CN VII)
Actions of platysma
- tenses skin of neck
- helps to depress mandible
- draws down lower lip and angle of mouth
External jugular vein
- begins posterior to angle of mandible by union of posterior auricular vein and posterior branch of retromandibular vein
- descends obliquely, superficial to sternocleidomastoid, toward middle of clavicle, pierces investing layer of deep cervical fascia, then drains into subclavian vein
Posterior auricular vein
Drains scalp posterior and superior to auricle
Retromandibular vein
- formed within parotid gland by union of superficial temporal and maxillary veins
- at lower end of gland it divides into anterior and posterior branches (anterior joins facial vein, posterior joins posterior auricular vein to form EJV)
Trubutaries of EJV
Transverse cervical
Supra scapular
Anterior jugular veins
Where does the anterior jugular vein begin?
In submental region by union of several small veins
Where does the anterior jugular vein descend?
Close to anterior midline, just superior to jugular (suprasternal) notch of sternum it turns laterally and passes posterior (deep) to sternocleidomastoid, then drains into external jugular vein
What are the right and left anterior jugular veins USUALLY joined by?
Usually joined across midline by jugular venous arch
Origin of sternocleidomastoid
Anterior surface of mnubrium of sternum and superior surface of medial third of clavicle (clavicular head)
Insertion of sternocleidomastoid
Two heads of origin, muscle passes superiorly, posteriorly, and laterally, then inserts into mastoid process and lateral part of superior nuchal line
Nerve supply to the sternocleidomastoid
- Accessory nerve (CN 11) for motor.
- Branches from ventral rami of C2 and C3 spinal nerves (proprioceptive)
What divides the anterolateral part of neck into anterior and posterior triangles?
Sternocleidomastoid
Sternocleidomastoid actions
- unilateral contraction
- bilateral contraction
Unilateral contraction of the sternocleidomastoid
- lateral flexion of head and neck to sam side of contracting muscle
- rotation of head and neck to opposite side of contracting muscle
Bilateral contraction of sternocleidomastoid
- draw head forward
- flexion of head and neck against resistance (doing sit up)
- if head is fixed, it can act as an accessory muscle of inspiration
What does deep cervical fascia consist of?
Connective tissue that supports muscles, vessels, nerves, and viscera of neck
Investing later of the deep cervical fascia
- superficial
- completely encircles neck like a collar, splitting to enclose sternocleidomastoid and trapezius
- roofs over anterior and posterior triangles
Pretracheal layer of deep cervical fascia
- anterior part of neck
- muscular part (encloses infrhyoid muscles) and visceral part (enclose thyroid, larynx, etc)
What is the pretracheal layer of the deep cervical fascia known as posterior to pharynx and esophagus?
Buccopharyngeal fascia
Prevertebral layer of deep cervical fascia
- located in posterior part of neck
- surrounds cervical vertebrae and anterior and posterior vertebral muscles
Carotid sheath of deep cervical fascia
- fascia tube extending from base of skull to root of neck
- contains common and internal carotid arteries, internal jugular vein, and vagus nerve ***
What is the retropharyngeal space of the deep cervical fascia?
Interval between buccopharyngeal fascia (anteriorly) and prevertebral fascia (posteriorly), filled with loose connective tissue
-closed laterally by carotid sheaths
Where does the retropharyngeal space of the deep cervical fascia extend?
Form base of skull to mediastinum
Loose connective tissue of the retropharyngeal space of the deep cervical fascia
Accommodates movements of pharynx and esophagus during swallowing
What represents a pathway through which neck infections can spread to mediastinum?
The retropharyngeal space of the deep cervical fascia
What are all the layers of the deep cervical fascia?
- investing layer
- pretracheal layer
- prevertebral layer
- carotid sheath
- retropharyngeal space
Anterior boundary of posterior triangle of neck
Posterior border of sternocleidomastoid
Posterior border of thee posterior triangle of the neck
Anterior border of the trapezius
Inferior border of the posterior triangle of the neck
Middle 1/3 of clavicle
What is the posterior triangle of the neck covered by?
- skin
- superficial fascia
- platysma
- investing layer of deep cervical fascia
Floor of the posterior trnagle of the neck
-splenius capitis
-levator scapulae
-scalenus posterior
-scalenus medius
All covered by the prevertebral layer of the deep cervical fascia
small part of scalenus anterior may be present but it is usually hidden by sternocleidomastoid
What divides the posterior triangle into occipital triangle and supraclavicular triangle?
Inferior belly of omohyoid
Origin of scalenus anterior
Transverse process of C3 and C6 vertebrae
Insertion of scalenus anterior
Superior surface of 1st rib and scalene tubercle
What muscle holds your neck up?
Scalenus anterior
Structures that are anterior to scalenus anterior
-subclavian vein
-phrenic nerve
-superficial cervical
-suprascapular arteries
-terminal part of thoracic duct
*
Structures that are posterior to scalenus anterior
-brachial plexus
-subclavian artery
*
What is the largest and longest of the scalene muscles?
Scalenus medius
Origin of scalenus medius
Transverse process of C2 to C7 vertebrae
Insertion of scalenus medius
Superior surface of 1st rib, between costal tubercle and groove for subclavian artery
What is the smalles of the scalene muscles?
Scalenus posterior
Origin of scalenus posterior
Transverse processes of C4 to C6 vertebrae
Insertion of scalenus posterior
Outer surface of 2nd rib
Nerve supply of scalene muscles
Direct muscular branch from ventral rami of cervical spinal nerves
Actions of scalene muscles
- lateral flexion of neck
- accessory muscles of inspiration (elevate 1st and 2nd ribs in forced inspiration)
Inferior belly of omohyoid
- Attaches to superior border of scapula, just medial to suprascapular notch
- passes anteriorly and superiorly, across lower part of posterior triangle of neck, then passes deep to sternocleidomastoid and ends in intermediate tendon
Superior belly of omohyoid
Begins at intermediate tendon, ascends almost vertically in anterior triangle of neck, then attaches to body of hyoid
Angulated course of omohyoid
Maintained by loop of deep cervical fascia that surrounds intermediate tendon and attaches inferiorly to clavicle and 1st rib
Nerve supply to omohyoid
Ansa cervicalis (ventral rami of C1 to C3)
Action of omohyoid
Depresses hyoid bone
Arteries of the posterior triangle of the neck
- subclavian artery (3rd part)
- superficial (transverse) cervical artery
- suprascapular artery
- dorsal scapular artery
- occipital artery
Veins of the posterior triangle of the neck
- external jugular vein and its tributaries
- subclavian vein (occasionally)
Nerves of the posterior triangle of the neck
- brachial plexus and branches arising from its roots and trunks
- accessory nerve
- branches of cervical plexus
What other structures are in the posterior triangle of the neck?
- some cervical lymph nodes (along course of accessory nerve and superficial/transverse cervical vessels)
- inferior belly of omohyoid muscle
