Regions and Compartments of the Neck Flashcards
Where does the neck start and end both anteriorly and posteriorly?
Anteriorly: extends from the lower border of mandible to the upper surface of manubrium of sternum
Posteriorly: from superior nuchal line on occipital bone to the IV Disc between C7-T1
What are the 4 major compartments of the neck and what is contained within each?
visceral compartment: contains viscera, trachea, oesophagus and thyroid gland
2 vascular compartments: contains vessels, carotid arteries, internal jugular vein and vagus vein
vertebral compartment: muscles of the spinal cord and the cervical spine
Layers through the neck (4)
1) Skin
2) Subcutaneous fat
3) Superficial fascial layer: 1 Layer where Platysma muscle sits (only in anterior neck)
4) Deep cervical fascia: 4 Layers
What are the 5 major fascial layers?
What is contained in each?
1) Superficial Fascial Layer: contains a thin sheet of muscle, Platysma
2) Investing Fascial Layer: surrounds all neck structures
3) Prevertebral Fascial Layer: surrounds vertebral column and deep muscles associated with the back
4) Pretracheal Fascial Layer:encloses the viscera of the neck
5) Carotid Sheaths: receive contributions from the layers above (excl superficial layer)
Which fascial layers make up the Deep cervical fascia?
Investing, Prevertebral, Pretracheal, Carotid sheaths
What is the thin sheet of muscle in the superficial fascial layer and what muscle group is it part of?
Where does this muscle begin and end and what is its innervation?
Platysma, part of the muscles of facial expression
Begins in the superficial fascia of the thorax and runs upward to attach to the mandible and blends with the muscles on the face
Innervation: CN VII: Facial n.
What are the attachments of the Investing fascial layer?
Describes its pathway (how it splits and regions)
Attaches posteriorly to the ligamentum nuchae and spinous process of the cervical vertebrae
- Splits as it passes forward to enclose the trapezius muscle
- Reunites into a single layer as it forms the roof of the posterior triangle
- Splits again to surround the sternocleidomastoid and infrahyoid muscles
What is the name of the flat, triangular muscle situated along the vertebral column (base) and pointing towards the shoulder (apex)
What does this muscle contribute to in the neck?
Trapezius, helps to form posterior triangle of the neck
What 2 important muscles are innervated by the accessory nerve?
What CN is this and how can its function be tested?
Trapaezius and Sternocleidomastoid are both innervated by the cccessory nerve, CN XI (11)
Test function: ask patient to shrug shoulder (this tests both SCM and Traps)
What muscle divides the neck into the anterior and posterior triangle?
Sternocleidomastoid
What bone is shown in the image below?
Is this part of the axial or appendicular skeleton?
Where is this bone derived from and what spinal level does it correlate to?
Hyoid bone, part of axial skeleton (has no articulations)
Derived from second and third pharyngeal arch and correlates to C3 level
How is the Hyoid bone suspended from the styloid process?
What structure is suspended from it?
What does it function as?
Suspended from styloid process by stylohyoid muscle
Larynx is suspended from it
Attachment for hyoid muscles (highly mobile)
Muscles located superior to the Hyoid are known as what?
List these 4 muscles?
Suprahyoid muscles
Stylohyoid, Digastric, Mylohyoid, Geniohyoid
Muscles located inferior to the Hyoid are known as what?
List these 4 muscles?
Infrahyoid muscles
Thyrohyoid, Sternothyroid, Sternohyoid, Omohyoid
Label the image below
List 4 muscles associated with the Prevertebral Fascial Layer
Describe the unique attachement of this fascial layer
Anterior/Middle/Posterior Scalene m. + Deep muscles of the back
Attachment points on the transverse processes splits into two layers, creating a longitudinal fascial space containing loose CT that extends from the base of the skull through the thorax
This fascial extension creates the axillary sheath which exits into upper limb
Describe the where the Pretracheal fascial layer begins and ends
Describe its anterior, lateral and posterior relations?
Begins superiorly at the hyoid bone and ends inferiorly in the upper thoracic cavity
Anteriorly: crosses the neck posterior to infrahyoid muscles, covers trachea and thyroid gland
Laterally: fascia continues and covers the thyroid gland and oesophagus
Posteriorly: referred to as buccopharyngeal fascia
What structure separates the oesophagus from the prevertebral layer?
Buccopharyngeal fascia (this is the posterior portion of the pretracheal fascial layer)
What 4 structures are contained within the 2 Carotid Sheaths?
1) common carotid artery (inferiorly)
2) Internal carotid artery (superiorly)
3) Internal jugular vein
4) vagus nerve
What forms the Carotid Sheath?
Contributions from Investing, Prevertebral, and Pretracheal layers (all deep fascial layers)
List the 3 fascial spaces?
1) Pretracheal Space
2) Retropharyngeal Space
3) Fascial Space within Prevertebral Layer
The fascial spaces provide a conduit for the spread of infections from neck to mediastinum.
State two potential spreads
Pretracheal Space: Infection can spread inferiorly into superior mediastinum, anterior to pericardium
Retropharyngeal Space: Infection can spread inferiorly into superior mediastinum, posterior to pericardium
Describe the borders of the anterior triangle of the neck
Posterior border: Anterior border of the sternocleidomastoid muscle
Superior border: The inferior border of the mandible
Anterior: midline of the neck
Describe the borders of the posterior triangle of the neck
Anterior border: Posterior border of the sternocleidomastoid muscle
Posterior border: anterior border of the trapezius muscle
Inferior border: middle one-third of the clavicle
The anterior triangle can be be furthur divided, list the 4 subdivisions
1) submandibular triangle
2) submental triangle
3) muscular triangle
4) carotid triangle
Label the Image below?
The posterior triangle can be be furthur divided, list the 2 subdivisions
1) occipital triangle
2) supraclavicular triangle
What is the musculoligamentous structure with a cartilaginous framework that is continuous with the trachea below?
What does this structure open to superiorly?
What is its function?
The larynx
Opens into the pharynx immediately superior/posterior
Functions as a valve (sphincter) to close respiratory tract and an instrument to produce sound
How is the larynx suspended from the hyoid and attached to the trachea?
How does it function to close respiratory tract?
By membranes and ligaments (highly mobile in the neck)
During swallowing, the dramatic upward and forward movements of the larynx facilitate closing the laryngeal inlet and opening the oesophagus
What is the nervous innervation to the Larynx?
Motor and sensory innervation of the larynx is from the vagus nerve, CN X
What are the 2 major arteries that supply all structures in the head and neck?
How do these branch?
Describe the exact pathway of this
R and L common carotid arteries which branch into:
- External Carotid artery
- Internal Carotid artery
CCAs ascend through the neck, just lateral to the trachea and oesophagus, within the carotid sheath (no branches as they pass through neck)
Near superior edge of thyroid cartilage each CCA divides into external and internal carotid arteries
What are the 2 main superficial veins that drain the head and neck?
External Jugular Vein
Anterior Jugular Vein
Which superficial vein crosses the Sternocleidomastoid muscle as it decends neck?
External Jugular vein
What is the main deep vein that drains the head and neck?
Describe its pathway?
Internal Jugular vein (drains skull, brain, superficial face, and neck)
1) Travels inside the carotid sheath (DEEP to SCM).
2) Joins the subclavian veins posterior to the sternal end of the clavicle to form the brachiocephalic veins
3) This has multiple tributaries
The Cranium can be divided into 2 parts, what are these?
1) Neurocranium (calvaria and skull base)
2) Viscerocranium (facial skeleton)
The layers of the Head can be remembered by the pneumonic SCALP, what does this stand for?
What can be said about the first 3 layers?
Skin, Connective tissue(dense), Aponeurotic layer, Loose CT, Pericranium
First 3 layers tightly bound together
Describe the muscular components and neural innervation of the Aponeurotic Layer
Firmly attached to the above layer of skin
Consists of the Occipitofrontalis muscle supplied by VII
Has 2 muscle bellies connected by the galea aponeurotica (epicranial aponeurosis)
What separates the aponeurotic layers from the pericranium?
What is the function of this?
Loose CT: facilitates movement of the scalp over the calvaria
Infections tend to localize and spread through this layer
The deepest layer of the scalp is Pericranium, what is this?
The Pericranium is the ‘periosteum on outer surface of calvaria’
Label the layers of the heald (SCALP)
What are the 2 major sources of nerves which innervate the scalp?
Cranial nerves and Cervical nerves
What are the 4 major muscle groups in head?
What is the innervation of each?
1) muscles of facial expression VII
2) muscle of the cheek (Buccinators) VII
3) muscles of the scalp (occipitofrontalis) VII
4) muscles of mastication V3
List the 4 muscles of mastication and their innervation
Innervated by CN V (V3 branch):
- Masseter
- Temporalis
- Buccinator (CN VII)
- Medial & Lateral Pterygoid
What are the divisions of CN VII, facial nerve (5)
1) Temporal
2) Zygomatic
3) Buccal
4) Mandibular
5) Cervical
