Lecture 14 - The Neck Flashcards
What does the investing layer of fascia surround?
neck, sternocleidomastoid, trapezius
What does the muscular layer of the pretracheal fascia surround?
infrahyoid muscles
What sheath surrounds the vascular compartment?
carotid sheath
What does the visceral layer of fascia encircle?
neurovasculature
What are the 5 layers of the deep cervical fascia?
- investing layer of cervical fascia
- muscular layer of pretracheal fascia
- visceral layer of pretracheal fascia
- carotid sheath
- prevertebral fascia
Which 2 veins drain blood from the superficial anterior neck?
anterior jugular vein
external jugular vein
Where do the anterior and external jugular veins drain?
into the subclavian veins
Why is a vertical incision use during a cricothyrotomy?
because the anterior jugular veins can be damaged
What are the “strap muscles” of the neck broadly grouped into?
suprahyoid and infrahyoid muscles
What is the primary action of the strap muscles?
moving the hyoid bone
What does the movement of the hyoid bone indirectly effect?
affect the pitch of the voice
Why does the movement of the hyoid bone indirectly effect the pitch of the voice?
beause of its connection with the thyroid cartilage of the larynx
What are the 2 primary functions of the suprahyoid muscles?
- elevates the hyoid
- depress mandible when the hyoid is fixed
What are the 2 primary functions of the infrahyoid muscles?
- depresses the hyoid
- moves the larynx
What are the suprahyoid muscles?
- mylohyoid
- digastric (ant. + post. bellies)
- stylohyoid
- geniohyoid
What are the 2 bellies of the digastric muscle joined by?
intermediate tendon
Do the digastric muscles directly attach to the hyoid bone?
no
Which 2 muscles are often together as some of the boundaries of the neck?
stylohyoid and the posterior belly of the digastric
What sling does the digastric muscle have?
facial sling
What is the geniohyoid innervated by?
anterior ramus of C1 via hypoglossal nerve
What are the mylohyoid and anterior belly of digastric muscles innervated by?
mandibular division of trigeminal nerve CN V3
What are the stylohoid and the posterior belly of digastric muscles innervated by?
facial nerve CN VII
What are the 4 infrahyoid muscles?
- sternohyoid
- thyrohoid
- sternothyroid
- omohyoid
What are teh superior and inferior bellies of the omohyoid joined by?
intermediate tendon
What is the ansa cervicalis formed by?
anterior rami of C1-C3
What nerve does the anterior ramus of C1 hitchhike on?
hypoglossal nerve
What levels are the superior root of the ansa cervicalis?
C1-C2
What levels are the inferior root of the ansa cervicalis?
C2-C3
What is the function of the thyrohyoid?
raises larynx when hyoid bone is fixed
What is the function of the sternothyroid?
depresses larynx
What are the 2 actions of the sternocleidomastoid?
uni: contralateral rot, ipsilateral flexion
bi: ext. of head/neck, flexion of neck
What is the innervation of the sternocleidomastoid?
spinal accessory nerve
What are the 2 triangles of the neck?
anterior and posterior triangles
What are the 4 divisions of the anterior triangle?
- submandibular (digastric)
- submental
- muscular (omotracheal)
- carotid
What are the 3 boundaries of the anterior triangle?
- inferior border of the mandible
- ant. border of sternocleidomastoid
- midline of neck
What are the 3 boundaries of the posterior triangle?
- post. border of sternocleidomastoid
- ant. border of trapezius
- superior border of clavicle
What neurovasculature is found in the posterior triangle?
external jugular vein
spinal accessory nerve
What is found in the punctum nervosum?
cutaneous branches of the cervical plexes C2-C4
What is the floor of the posterior triangle formed by?
- levator scapulae
- middle scalene
- anterior scalene
- posterior scalene
Which 2 muscles does the brachial plexus emerge from?
anteiror and middle scalenes
Which triangle is the only unpaired triangle?
submental triangle
What are the boundaries of the submandibular triangle? (3)
- ant. belly of digastric
- post. belly of digastric/stylohoid
- inferior border of mandible
What are the major contents of the submandibular triangle? (5)
- submandibular gland
- lymph nodes
- CN XII
- nerve to mylohyoid
- facial artery
What are the boundaries of the submental triangle? (2)
- ant. belly of digastric (bilaterally)
- hyoid bone
What are the major contents of the submental triangle? (2)
- anterior jugular vein
- lymph nodes
What are the boundaries of the muscular triangle? (3)
- sup. belly of omohyoid
- ant. border of sternocleidomastoid
- midline of neck
What are the major contents of the muscular triangle? (3)
- infrahoids
- thyroid gland
- larynx
What are the boundaries of the carotid triangle? (3)
- sup. belly of omohyoid
- ant. border of sternocleidomastoid
- post. belly of digastric
What are the major contents of the carotid triangle? (5)
- carotid aa. (common, internal, external)
- internal jugular v.
- CN X, XI, XII
- ansa cervicalis
- superior laryngeal nerve
Between which vein and artery is the vagus nerve found in the carotid triangle?
internal jugular vein and carotid arteries
In addition to some of the infrahyoid muscles, the muscular triangle also contains…
the larynx, trachea, thyroid gland, parathyroid glands
Which gland is the largest endocrine gland in the body?
thyroid gland
What glands are found on the thyroid gland?
parathyroid glands (4; 2 superior and 2 inferior)
What is the pyramidal lobe on the thyroid gland a remnant of?
thyroglossal duct
What are the 2 arteries involved in thyroid vasculature?
superior thyroid (from external carotid) and inferior thyroid artery (from subclavian)
What is found near the lobes of the thyroid gland?
recurrent branches of the vagus nerves
What nerves are at risk during a thyroidectomy?
laryngeal nerves
What does damage to an external branch of the superior laryngeal nerve result in?
monotone voice
What does damage to a recurrent laryngeal nerve result in?
hoarseness
What is found in the thyroid venous plexus?
- superior thyroid vein
- middle thyroid vein
- inferior thyroid vein
