What two things constitute the "occiput"?
The external occipital protuberance and the superior nuchal lines.
Where is the hyoid bone palpable?
Anteriorly immediately superior to the prominence of the thyroid cartilage (opposite the third cervical vertebrae) and laterally at its greater horn.
What vertebrae is the thyroid cartilage located opposite?
Opposite the fourth and fifth cervical vertebrae
What are the important aspects of the cervical fascial layers?
- Bind deeper structures giving them strength and continuity while allowing movement.
- Allow movement of visceral components while swallowing, independent of movements of the neck
- Help to isolate spread of infection
The superficial fascial layer is composed of connective tissue and a fatty layer that fills in the space between the skin and deep fascia covering muscles.
What muscle is located within the superficial cervical fascia layer?
What is the action of the platysma muscle?
Draws the corner of the mouth downward, depresses mandible. elevates skin of chest.
Innervation of the platysma muscle?
Cervical branch of facial nerve. (CN VII)
What are the layers of the deep cervical fascia?
From superficial to deep...
- Investing fascia
- Infrahyoid fascia
- Cervical visceral fascia
- Prevertebral fascia
- Alar fascia
- Carotid sheath
The investing fascia is a cylinder of fascia attached above and below to bony prominences, surrounds the entire neck from above downward, and posterior to anterior provides a roof for the anterior and posterior trianges and invests what muscles?
The trapezius and SCM muscles
What is the investing fascia continuous with superiorly?
What does it form a capsule for?
The parotid fascia in the soft tissue interval between the mastoid and angle of the mandible.
For the submandibular gland.
The infrahyoid fascia is the second layer of deep fascia, beginning at the hyoid bone and thyroid cartilage.
This fascia forms what two definite layers?
What do these layers invest?
- Superficial layer
- Deep layer
... right, the superficial and deep layers of a deep layer fascia. Nice work anatomists.
These invest the infrahyoid muscles.
The superficial layer of the infrahyoid fascia is prolonged inferiorly to attach to the posterior surface of the manubrium. What two muscles does this fascia invest?
Sternohyoid and omohyoid
The superficial layer of the infrahyoid fascia fuses laterally with the periosteum of the clavicle and first rib, where it forms a sling for what structure?
The intermediate tendon of the omohyoid muscle.
The deep layer of the infrahyoid fascia is prolonged inferiorly to attach to the posterior surface of the manubrium. What two muscles does this layer invest?
The sternothyroid thyrohyoid muscles.
Both lamina of the infrahyoid fascia fuse inferiorly and laterally what structures? (3)
- Fibrous pericardium (via the superior sternopericardial ligament)
- adventitia of the brachiocephalic veins
- Carotid sheath
The cervical visceral fascias encircle the visceral structures of the neck (pharynx, esophagus, larynx, trachea and thyroid gland) and are composed of two seperate anterior and posterior fascias which meet and fuse laterally.
What are these two fascias?
The pre-tracheal layer of the cervical visceral fascia is located anterior to the larynx and trachea. Is attached to the hyoid bone superiorly, and blends laterally with the buccopharyngeal fascia.
Inferiorly it is prolonged to attach to the adventitia of the aortic arch and fuses with the fibrous pericardium.
What does it split to enclose?
The thyroid gland.
The buccopharyngeal fascia attaches superiorly to the base of the skill, fuses laterally with the pre-tracheal fascia at the sites of the pharyngeal constrictor muscle attachement points. And is prolonged inferiorls until it fuses with the adventitia of the esophagus.
What muscles are covered on their external surface by this fascia?
The buccinator and pharyngeal constrictor muscles.
What is the fifth layer of cervical deep fascia?
What does the pre-vertebral fascia form the floor of?
What does it cover here? (4)
The posterior cervical triangle.
It covers the...
- Levator scapulae
What are the two specializations of the pre-verterbral fascia?
Sibson's Fascia and the axillary sheath
The suprapleural membrane is continuous with the underside of the scalene muscles and reinforces the dome of cervical pleura. What else is this known as?
The Alar fascia is an anterior bifurcation of what fascia?
What is the neurovascular component of the deep fascia?
The carotid sheath
The carotid sheath surrounds what structures?
- Common carotid arteries
- internal carotid arteries
- internal jugular vein
- vagus nerve
All deep fascias blend laterally with what single structure?
The carotid sheath.
Therefore, care must be exercised when dissecting, as there are structures within them that should be retained. ( i.e. Ansa Cervicalis)
Since all deep fascias of the neck communicate with and help form the carotid sheath, infections within the pre-tracheal, retrovisceral, and danger spaces can invade the carotid sheath. What is the most concerning danger in this situation?
The infection has a path that it may dissect through to involve the aorta, causing aortitis.
What are the four cervical fascial spaces?
- Suprasternal space
- Pre-tracheal (or Visceral) space
- Retrovisceral, retropharyngeal, retroesophageal
- Danger space
What is the pre-tracheal/visceral space located between?
Deepest layer of infrahyoid fascia and the pre-tracheal fascia
Where is the retrovisceral space located?
Between the buffopharyngeal and alar fascias from the base of the skill above to a point approximately opposite CV7-TV3.
Where is the danger space located?
Between the pre-vertebral and alar/buccopharyngeal fascias, extending from the base of the skull to the diaphragm between the cervical column and the esophagus.
Infections within the danger space can lead to retropharyngeal abscess which can cause what? Where can this dissect?
dysphagia and dysarthria
posterior aspect of the superior and posterior mediastinum
What can chronic tonsilitis lead to?
Mediastinal abcess, causing inflammation of the esophagus as far distally as the diaphragm.
Where can infections of the anterior visceral compartment (pre-tracheal space) dissect to? What does this cause?
Dissect to the superior mediastinum, causing inflammation of the brachiocephalic veins, aorta and pericardium.
What is the action of the sternocleidomastoid?
Unilaterally acting: rotates head toward opposite side, while elevating the chin. (essentially side bends per buck book)
Bilateral: Flexes head, limited extension of the atlanto-occipital joint
What is the innervation of the SCM?
CN XI and cervical spinal nerves C2 and C3
What is torticollis?
Is it congenital or acquired?
Shortening of the SCM which places the patients head in a position side bent to the same side, and rotated to the opposite side of the affected muscle.
Can be either congenital or acquired
The gross boundaries of the neck are bisected obliquely by the SCM, thereby creating what?
The anterior and posterior triangles
What are the anterior, posterior and inferior boundaries of the posterior triangle?
Anterior - SCM
Inferior - Clavicle
Posterior - Trapezius
The posterior triangle is subdivided by the passage of the omohyoid muscle into what two things?
- Occipital Triangle
- Omoclavicular triangle
What are the boundaries ot the occipital triangle?
What are the boundaries of the omoclavicular triangle?
Inferior belly of omohyoid
What are the posterior, superior and "mid-sagittal" boundaries of the anterior triangle?
Posterior - SCM
Superior - Angle of the mandible
Mid-sagitally - imaginary line (oh yeah!)
The anterior triangle is subdivided by the passage of the digastric and omohyoid muscles to form what triangles? (4)
What are the external jugular veins formed by?
The union of the posterior division of the retromandibular and posterior auricular veins at the angle of the mandible.
What is the course of the external jugular vein?
Descends from its formation superficial to the SCM, pierces the investing fascia to gain the root of the neck behind the clavicle where it terminates in the subclavian vein.
What are the 4 tributaries of the external jugular veins?
- Posterior external jugular v. (from lateral occiput)
- Transverse cervical v.
- Suprascapular v.
- Anterior Jugular v.
What are four causes of prominence of the external jugular vein beyond normal that are discussed in the Buck book?
- heart failure
- SVC obstruction
- enlarged supraclavicular lymph nodes
- increased intrathoracic pressure
Laceration of the external jugular v. along the posterior border of the SCM can lead to what?
What is this due to?
Due to negative intrathoracic pressure.
What forms the anterior jugular veins?
small veins in the submental and submandibular regions coalesce at the level of the hyoid bone to form the anterior jugular vein.
What allows the two anterior jugular veins to communicate?
The jugulovenous arch
Sorry to cheap out here, but just drawy the anastamotic connections of the cervical region described on pages 26 and 27 of the Buck book.
What are the origins of the cutaneous nerves?
C1 has no dorsal root in what percent of individuals?
What is the course and section of innervation of the dorsal rami of C2?
The greater occipital nerve pierces the semispinalis capitis and trapezius and ascends to innervate the skin over the vertex and posterolateral area of the skill.
The dorsal rami of C3-C6 pierce the deep musculature to reach subcutaneous areas near the dorsal midline and extend laterally to cutaneous areas over the?
C1-C4 ventral rami form what?
The cervical plexus
What are the nerves that emerge from beneath the posterior border of the SCM in the posterior triangle to distribute to their respective receptive fields?
What are their cord levels?
- Lesser occipital nerve (C2,3)
- Great auricular nerve (C2,3)
- Transverse cervical nerve (C2,3)
- Supraclavicular nn. (C3,4)
What are the three branches of the supraclavicular nerve?
- Medial supraclavicular nn
- Intermediate supraclavicular nn
- Lateral supraclavicular nn
What does the lesser occipital nerve innervate?
The medial surface of the ear and the skin behind the ear
Wjat dpes tje great auricular n innervate?
skin of the mastoid process, lower portion of both surfaces of the ears, and the inferior portion of the angle of the mandible and parotid region.
What do the transverse cervical n. and cervical branch of the facial nerve unite to form?
Ansa cervicalis siperficialis (function unkown)
What does the transverse cervical n innervate?
Skin and subutaneous tissue of the anterior triangle from the mandible to the sternum.
What does the medial supraclavicular nn innervate?
skin at base of neck, upper sternum and sternoclavicular joint
What does the intermediate supraclavicular nn innervate?
Skin over the pec major as far inferior as the third rib
What does the lateral supraclavicular nn innervate?
Cutaneous innervation to the prominence of the shoulder.
The cutaneous branches of the cervical plexus are locally anesthetized (cervical nerve block) during the normal course of surgical approaches to the superficial or deeper areas of the neck. (radical neck dissection of cancerous lymph nodes, etc.) Why mustn't you use this procedure on patients with respiratory or cardiac disease?
Because the phrenic n. shares the spinal cord levels of innervation with the spinal cord levels of origin of the cervical plexus. Thus this paralyzes the ipsilateral hemidiaphragm. Bad in respiratory or cardiac compromised patients!
What are the superficial cervical lymph nodes? (4)
- external jugular
- anterior jugular
Where do the superficial cervical lymph nodes drain to?
The deep cervical lymph nodes that parallel the internal jugular vein.