65 - Regions of the Neck Flashcards
Compartments of the neck 1 2 3 4
1) Vertebral
2) Visceral
3) Two vascular compartments
4) Superficial fascia
Unique aspect of superficial fascia of neck
Platisma muscle blends with muscles of face, therefore shares nerve supply
Superficial veins of neck
External jugular vein (descends vertically along sternocleidomastoid from angle of mastoid).
Anterior jugular vein
Muscles enclosed by investing fascia
Sternocleidomastoid anteriorly, trapezius posteriorly
Contents of pretracheal fascia
Contains thyroid, parathyroids, thymus, trachea and oesophagus.
Fascia that closes pretracheal facia compartment posteriorly
Buccopharyngeal fascia
Extent of the pretracheal fascia
Extends upwards to the hyoid bone, down to the fascia of the arch of the aorta.
Neck anatomy leading to spread of infection
Parts of fascia communicate with mediastinum.
Infection can spread from mediastinum to neck
Triangles of the neck
Anterior triangle (in front of the sternocleidomastoid, below mandible)
Posterior triangle (behind sternocleidomastoid, in front of trapezius, above middle 1/3 of clavicle)
Anterior vertebral muscles 1 2 3 4
- Suprahyoid & infrahyoid muscles
- Lie between investing fascia & pretracheal fascia
- Act to steady or move the hyoid bone and larynx
- Innervated by anterior rami of cervical nerves
Innervation of suprahyoid and infrahyoid muscles
Anterior rami of cervical nerves
Role of suprahyoid muscles
Connect hyoid with mandible.
Make up floor of the mouth.
Elevate the hyoid in the larynx.
Role of infrahyoid muscles
‘Strap muscles’
Attach hyoid bone with the sternum, clavicle, scapula.
Depress the hyoid and larynx
Muscles in the anterior triangle of neck
Suprahyoid and infrahyoid muscles
Vessels of the anterior triangle of neck
1
2
- Common carotid - passes in carotid sheath to level of C3/4 (upper border thyroid cartilage).
- Internal carotid - no branches in neck, however contains carotid sinus & carotid body (baro & chemoreceptors, respectively).
Course of external carotid
Anterior to internal carotid.
Has three branches in front, two branches behind.
Ascends to parotid gland, where it divides into superficial temporal and maxillary.
Branches of the external carotid 1 2 3 4 5 6
Anterior branches
1) Thyroid artery (most inferior)
2) Lingual artery
3) Facial artery (most superior)
Posterior branches
1) Posterior auricular artery
2) Occipital artery
1) Deep aspect gives off ascending pharyngeal artery
Veins of the anterior triangle of the neck
Internal jugular vein (lateral to artery, within carotid sheath).
Jugular foramen is at the top of the anterior triangle (with CNIX, X, XI)
Paths of CN IX, X, XI in the neck
CNIX moves forward in the neck
CNX moves down
CNXI moves back
Path of CNXI in the neck
Moves backwards into posterior triangle to trapezius.
Cranial nerves of the anterior triangle of the neck
IX, X, XI, XII
Cranial nerves passing forwards in neck
CNIX, CNXII (passes between internal and external carotids)
Location of the thyroid gland 1 2 3 4
- 2 lobes between upper border of thyroid cartilage above & 6th tracheal ring below
- Isthmus, between 2nd & 3rd tracheal rings
- Enclosed by pretracheal fascia
- Can often have an extrapyramidal node, usually ascending upwards from the isthmus and to the left.
Where do the recurrent laryngeal nerves run in the neck?
Embedded in fascia behind the thyroid gland.
Run between trachea/oesophagus and pretracheal fascia
What can an enlarged thyroid impact on? 1 2 3 4
Recurrent laryngeal nerve (hoarse voice)
Oesophagus (swallowing)
Trachea (breathing)
Internal jugular vein (venous distension)
Blood supply of the thyroid 1 2 3 4 5 (a, b, c)
Arteries
- Paired superior thyroid (usually 1st branch of external carotid artery)
- Paired inferior thyroid (branch of subclavian artery, anastomose vertically and along midline)
- Branches anastomose vertically & across midline
- Occasional (10% of people) single thyroid ima artery passes along isthmus
Veins
3 pairs of veins:
- Superior, middle, inferior thyroid
Development of the thyroid gland
Develops from an outgrowth of the pharynx.
Descends from the foramen caecum (in the tongue).
Descends through thyroglossal duct, which normally disappears later in development (but can persist, and produce thyroid hormone)
Number of parathyroid glands
Four (superior and inferior on each lobe of thyroid).
Location is variable, particularly that of inferior.
Floor of the posterior triangle of the neck
Vertebral muscles.
Include levator scapulae, scalene muscles,
Arteries in the posterior triangle
Subclavian system
Supplies upper limb, almost ½ brain, most of spinal cord (via vertebral artery) & part of thoracic wall
Main branches in neck:
•
Vertebral (normally 1st branch) – passes in triangle between longus colli & scalenus anterior
•
Thyrocervical trunk (gives off inferior thyroid to thyroid gland)
Where do the nerves and vessels of the upper limb run in the neck?
Between scalenes anterior and medius
Nerves and vessels of the upper limb running in neck
CNXI (runs deep to, or through sternocleidomastoid), into posterior triangle. Here it tracks along levator scapulae.
Subclavian arteries
Cervical plexus
Path of CNXI in the neck
CNXI (runs deep to, or through sternocleidomastoid), into posterior triangle. Here it tracks along levator scapulae.
Cervical plexus
Cervical Plexus (nerve loops from ventral rami of C1-4)
Phrenic (C3,4,5) branches
Superficial (cutaneous) branches to skin
Deep branches
- Ansa cervicalis (motor to infrahyoid muscles of neck – attach to hyoid)
Note: roots (rami) of brachial plexus (pass between scalenus medius & anterior)
Contents of posterior triangle
Cervical plexus
CNXI
Subclavian arteries
Vertebral muscles make floor
Lymphatic drainage of neck 1 2 3 4
Superficial cervical
- Horizontal (junction of head/neck)
- Vertical (along external jugular)
Deep cervical (along internal jugular)
- Upper group (includes jugulo-digastric or tonsillar node – drains palatine tonsil)
- Lower group (includes supraclavicular/jugular-omohyoid node – ‘final sentinel’ node - clinical significance)
