Neck: Cervical Fascia, Triangles of the Neck, and Thyroid Gland Flashcards
Bony Framework of Neck
- Cervical vertebrae
- Inferior/Posterior skull
- Mandible
- Clavicle and Manubrium
- Hyoid bone
Hyoid Bone
- C3 vertebral level
- Fractured during strangulation
- No bony articulation
- Suspended by muscle attachment
Hyoid Bone Ligament Attachment
- Stylohyoid ligament
- Thyrohyoid membrane
Cervical Superficial Fascia Contains
- Fatty connective tissue
- Nerves
- Vasculature
- Platysma muscle
Platysma Innervation
- Innervated by CN VII
Platysma Function
- Facial expression
- Depress mandible
Platysma Muscle Attachment
- Deep fascia over upper chest
- Mandible
Deep Cervical Fascia
- Fascial layers
- Encircle neck structures
- Form anatomic compartments
3 Deep Cervical Fascial Layers (Superficial to Deep)
- Investing
- Pretracheal
- Prevertebral
Investing Cervical Fascial Layer Attachments
- Superior: skull and mandible
- Inferior: scapular spine, clavicle, acromion, manubrium
Investing Cervical Fascial Layer Envelopes
- Trapezius
- Sternocleidomastoid
- Parotid/submandibular salivary glands
Paratracheal Cervical Fascial Layer Attachments
- Hyoid bone (superior)
- Fibrous pericardium (inferior)
Paratracheal Cervical Fascial Layer Envelopes
- Infrahyoid muscles
- Thyroid gland
- Esophagus
- Trachea
Buccopharyngeal Fascia Located
- Posterior to pharynx/esophagus
Prevertebral Cervical Fascial Layer is a Sheath for
- Vertebral column
- Deep muscles
Prevertebral Cervical Fascial Layer Attachments
- Cranial base (superior)
- Endothoracic fascia (inferior)
Alar Fascia
- Anterior to prevertebral fascia
- Fuses with buccopharyngeal fascia around T4
Carotid Sheath
- Formed by all 3 deep cervical fascial layers
- Cranial base > root of the neck
Carotid Sheath Contents
- Common and internal carotid arteries (medial)
- IJV (lateral)
- Vagus nerve (posterior)
- Deep cervical lymph nodes
- Carotid sinus nerve
- Sympathetic nerves
- sometimes ansa cervicalis is embedded in the sheath*
Fascial Spaces of the Neck
- Pretracheal space
- Retropharyngeal space
- Danger space
Pretracheal Space
- Posterior to infrahyoid muscles
- Surrounds trachea
- Infection: superior > anterior mediastinum
Retropharyngeal Space
- Between alar/buccopharyngeal fascia
- Infection: superior mediastinum
Danger Space
- Between alar/prevertebral fascia
- Communicates with the posterior mediastinum
Regions of the Neck
- Posterior cervical and sub-occipital regions: (covered with back)
- Lateral cervical region (Posterior triangle) *
- Anterior cervical region (Anterior triangle) *
- Sternocleidomastoid separates Anterior and Posterior triangles
Sternocleidomastoid Attachments
- 2 heads (inferior attachments/origins):
- Sternal: attaches to manubrium
- Clavicular: medial 1/3 of clavicle
- Superior attachment (insertion): mastoid process and superior nuchal line
Sternocleidomastoid Sternal Attachment
- Manubrium
Sternocleidomastoid Clavicular Attachment
- Medial 1/3 of clavicle
Sternocleidomastoid Superior Attachment (Insertion)
- Mastoid process
- Superior nuchal line
Sternocleidomastoid Innervation
- Spinal accessory nerve
Sternocleidomastoid Function
- Bilateral contraction: flexion of cervical spine
- Unilateral: lateral flexion with rotation
- Accessory muscle of respiration
Lateral cervical region (Posterior Triangle of the Neck) Boundaries
- Anterior: posterior border of SCM
- Posterior: anterior border of trapezius
- Inferior: clavicle (middle 1/3)
- Superior (Apex): where trap and SCM meet
- Roof: overlying fascia
- Floor: scalenes, splenius capitis, levator scapulae (covered by prevertebral fascia)
Inferior Belly of Omohyoid Muscle Divides Posterior Triangle into
- Occipital triangle
- Omoclavicular (subclavian) triangle
Anterior Cervical Region (Anterior Triangle) Boundaries
- Anterior: midline of neck
- Posterior: anterior border of SCM
- Superior: inferior border of mandible
- Inferior (Apex): jugular notch
- Roof: overlying fascia
- Floor: pharynx, larynx, thyroid gland
Blood Vessels of Posterior Triangle
- Occipital artery (branch of external carotid)
- 3rd part of subclavian artery/vein (subclavian artery pulse is palpable)
- Suprascapular artery/vein
- Transverse cervical artery/vein (cervicodorsal)
- Arteries are branches of thyrocervical trunk
- External jugular vein
Nerves of Posterior Triangle
- Spinal accessory nerve (CNXI)
- Roots and trunks of brachial plexus
- Suprascapular nerve
- Cutaneous branches of cervical plexus
- Phrenic nerve
Omohyoid Muscle Located in this Triangle
- Posterior triangle
Omoclavicular (Subclavian) Triangle Content
- Subclavian vessels
- External jugular vein
- Trunks of the brachial plexus
External Jugular Vein Formed by
- Posterior division of retromandibular vein
- Posterior auricular vein
Tributaries of External Jugular Vein
- Anterior jugular vein
- Cervicodorsal vein
- Suprascapular veins
Spinal Accessory Nerve (CN XI) Pathway
- Enters posterior triangle at jxn of middle and superior 1/3s of SCM
- Deep to investing cervical fascia
- Passes deep to SCM and trapezius
- Innervates: SCM and trapezius
Cervical Plexus
- Formed by the anterior rami of C1-4
- Cutaneous (sensory branches) are in the posterior triangle
Roots of Brachial Plexus
- Anterior rami (C5-T1)
- Pass between anterior and middle scalene
Trunks of Brachial Plexus
- Anterior rami unite to form trunks
- Pass through cervico-axillary canal enter axilla (we will pick up in Upper Extremity)
Branches of Brachial Plexus in Posterior Triangle
- Suprascapular nerve
- Nerve to subclavius
Cutaneous (Sensory) Branches of Cervical Plexus
- Posterior border of SCM, mid-belly (nerve point of the neck)
- Lesser occipital (C2)
- Great auricular (C2,3)
- Transverse cervical (C2,3)
- Supraclavicular (C3,4)
Nerve Point of the Neck
- Posterior border of SCM
- Mid-belly
Supraclavicular (C3,4) Branch of Cervical Plexus Originates
- From similar spinal cord segments as phrenic nerve
Anterior Cervical Region (Anterior Triangle) Boundaries
- Anterior: midline of neck
- Posterior: anterior border of SCM
- Superior: inferior border of mandible
- Inferior (Apex): jugular notch
- Roof: overlying fascia
- Floor: pharynx, larynx, thyroid gland
Anterior Cervical Muscles
- Suprahyoid muscles
- Infrahyoid muscles
- Stabilize and move the hyoid bone and larynx
- Named based on attachment points