Mobile element; when at rest, lies at C3 vertebral level
Muscles and ligaments connect the hyoid to the mandible, manubrium, scapulae, cranium, and thyroid cartilage of the larynx
Hyoid Bone
Body
Green
Greater horn
Blue
Lesser horn
Pink
Clavicle
Manubrium
Mastoid process (of temporal bone)
Mandible
Thyroid ("Adam's Apple") and cricoid cartilages
Trachea
Surface Landmarks
Contains: fat, cutaneous nerves, superficial blood vessels, superficial cervical lymph nodes, and platysma
Superficial cervical fascia
Thin sheet of muscle that covers the anterolateral aspect of the neck; it is a muscle of facial expression, innervated by facial nerve (CN VII).
Platysma
Forms compartments within the neck
Can limit the spread of infection or act as a conduit to promote the spread of infection when they are continuous with adjacent regions
Deep cervical fascia
Vertical tube of deep cervical fascia
Continuous superiorly with the cranial cavity and continuous inferiorly with the mediastinum (potential pathway for spread of infection)
Contents of the carotid sheath:
- Common carotid and internal carotid arteries (
Carotid sheath
Potential space between the layers of deep cervical fascia
Facilitates movement/expansion of pharynx, esophagus, larynx, and trachea
An infection in the retropharyngeal space may cause difficulty swallowing/speaking
Retropharyngeal space
Posterior border: Sternocleidomastoid muscle
Superior border: Mandible
Anterior border: midline of the neck
Anterior Triangle
Green
Action Rule: depress hyoid (e.g., during swallowing)
Innervation Rule: ansa cervicalis, except thyrohyoid m. (C1)
Infrahyoid muscles
Sternohyoid
Omohyoid
Note: superior belly in anterior triangle, inferior belly in posterior triangle
Sternothyroid
Note: also depresses larynx
Thyrohyoid
Action: elevate hyoid (e.g., during swallowing)
Most innervated by cranial nerves
Suprahyoid Muscles
Mylohyoid
Innervation: Mandibular nerve
Diagastric
Anterior belly (mandible to hyoid)
Posterior belly (mastoid region to hyoid)
Innervation:
Anterior belly: mandibular nerve (CN V3)
Posterior belly: facial nerve (CN VII)
Note: also depresses mandible
Stylohyoid
Innervation: facial nerve (CN VII)
Geniohyoid
Innervation: C1 via hypoglossal nerve
Subdivision of anterior triangle
Between posterior belly of digastric, SCM and omohyoid muscles
Common carotid artery bifurcates in this triangle into its two main branches
Carotid triangle
Posterior border: Trapezius
Inferior border: Clavicle
Anterior border: Sternocleidomastoid (SCM) muscle
Muscles within border:
Inferior belly of omohyoid
Scalenes
Splenius capitus
Levator scapulae
Posterior triangle
Blue
Sternocleidomastoid
Origin: manubrium (sternal head); clavicle (clavicular head)
Insertion: Mastoid process (temporal bone)
Action: Unilateral contraction: ipsilateral lateral flexion of the neck and
contralateral rotation of the head
Bilateral contractio
Scalenes
Action: laterally flex neck or elevate ribs
Innervation: cervical plexus
Ventral rami C1-C4
Cutaneous branch (Sensory)
Ansa cervicalis (Motor)
Phrenic Nerves
Cervical plexus
Sensory
Become visible as they emerge from the 'nerve point of the neck' (midpoint of the posterior border of sternocleidomastoid)
Can inject anesthetic here when conducting surgical procedures in the neck
Cutaneous branches of the cervical plexus
Loop formed by C1-C3
Motor Branch
Superficial to the carotid sheath
Innervates most infrahyoid muscles
Some fibers hitch a ride with hypoglossal nerve
Ansa cervicalis
(C3-C5)
Descend on superficial surface of the anterior scalene
Phrenic nerves
Arch of the aorta
Orange
Brachiocephalic trunk
Blue
Right common carotid
Yellow
Left common carotid
Pink
Located at the bifurcation of the common carotid
Chemoreceptors that monitor blood gas levels.
Innervated by glossopharyngeal
Carotid Body
Enlargement of internal carotid artery near its point of bifurcation
Contains baroreceptors that monitor blood pressure
Innervated by glossopharyngeal
Carotid Sinus
Massage of this area activates glossopharyngeal (CN IX) nerve endings in the sinus and helps to slow heart rate via parasympathetic output through the vagus nerve
Carotid sinus massage
Internal carotid arteries
Courses superiorly within the carotid sheath
No branches in the neck
External carotid arteries
Supplies neck, scalp, part of orbit
Many branches in neck
Occipital artery
Supplies scalp
Green
Facial artery
Supplies face
Yellow
Lingual artery
Supplies tongue
Pink
Ascending pharyngeal artery
Orange
Superior thyroid artery
Supplies thyroid gland and larynx
Blue
Internal thoracic artery
Orange
Thyrocervical trunk
Purple
Inferior thyroid artery
Yellow
Subclavian artery
White
Transverse cervical artery
Blue
Suprascapular artery
Green
Vertebral artery
Transverse foramina of the upper six cervical vertebrae allow for the passage of the vertebral arteries
Blue
External jugular veins
Superficial to SCM
Receive blood from the scalp, face, neck and shoulder
Empty into subclavian veins
Green
Internal jugular vein
Course inferiorly within the carotid sheath
Receive blood from structures within the cranial cavity
Join the subclavian veins at venous angle
Blue
Facial vein
Orange
Subclavian vein
Course between clavicle and 1st rib, anterior to the anterior scalene m.
Receive blood from the upper extremity, head and neck
Purple
A catheter can be readily introduced into the subclavian vein as it courses just inferior to the clavicle (e.g., to administer meds, fluids)
Central line
Yellow
Superficial tissues of neck drain into superficial cervical lymph nodes along external jugular vein
Lymph from face and scalp drains into superficial ring lymph nodes
All lymph from head and neck eventually drains into deep cervical lymph nodes, along int
Lymphatics