Lecture 2&3 - Surface anatomy, fascias and spaces, Triangles and Superficial Structures, Lions Tigers and bears. Oh my! Flashcards
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?
Platysma Muscle
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?
(6)
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)
Inferiorly…
- Fibrous pericardium (via the superior sternopericardial ligament)
- adventitia of the brachiocephalic veins
Laterally…
- 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?
- Pre-tracheal
- Buccopharyngeal
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?
Pre-vertebral fascia
What does the pre-vertebral fascia form the floor of?
What does it cover here? (4)
The posterior cervical triangle.
It covers the…
- Scalenes
- Levator scapulae
- Splenius
- Semispinalis
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?
Sibson’s fascia
The Alar fascia is an anterior bifurcation of what fascia?
pre-vertebral 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.