Superficial Triangles and Cervical Viscera Flashcards
What nerve is associated with the first (mandibular) pharyngeal arch? What muscles are associated with it?
Trigeminal (CN V)
Muscles of mastication Mylohyoid Anterior belly digastric Tensor tympanic Tensor veli palatini
What nerve is associated with the second (hyoid) pharyngeal arch? What muscles are associated with it?
Facial n (CN VII)
Muscles of facial expression
Stapedius
Stylohyoid
Posterior belly digastric
What nerve and muscle are associated with the third pharyngeal arch?
Glossopharyngeal (CN IX)
Stylopharyngeus m.
What nerve is associated with the fourth and sixth pharyngeal arches? What muscles are associated with them?
CN X: Vagus n. (Superior laryngeal branch and recurrent laryngeal branch)
Cricothyroid Levator veli palatini Constrictors of pharynx Intrinsic muscles of larynx Striated mm of esophagus
What skeletal structures are associated with the fourth and sixth arches?
Thyroid cartilage Cricoid cartilage Arytenoid cartilage Corniculate cartilage Cuneiform cartilage
Meckel’s cartilage leads to development of what head/neck structure?
Mandible
[also contributes to alisphenoid, malleus, and incus]
Development of the hyoid involves what 2 arches?
Arches II and III
The larynx is derived from what pharyngeal arch?
4th arch
What muscles are supplied by the spinal accessory n. (CN XI)?
Sternocleidomastoid m.
Trapezius m.
Borders of posterior triangle of the neck
Posterior: trapezius m.
Anterior: SCM m.
Inferior: middle 1/3 of clavicle
Roof = investing fascia Floor = prevertebral fascia
Borders of anterior triangle of the neck
Superior: inferior border of the mandible
Lateral: anterior border of SCM m.
Medial: sagittal line down the midline of the neck
Roof = investing fascia Floor = visceral fascia
What fossa is present in the anterior cervical triangle?
Lesser supraclavicular fossa
What fossa is present in the posterior cervical triangle?
Greater supraclavicular fossa
What is the most superficial cutaneous muscle of facial expression?
Platysma m.
What innervates the platysma m.
Cervical branch of facial n.
What happens with unilateral contraction of SCM?
Turns head to opposite side (particularly sternal head of SCM)
T/F: SCM can either flex or extend the head
True — depending on center of rotation it can do either
If center of rotation is anterior to the OA, the SCM extends the head
If center of rotation is posterior to the OA, the SCM flexes the head
What condition is characterized by contracture of the SCM?
Muscular torticollis
What is the most common cause of muscular torticollis
Birth trauma
[can also be muscle or nerve injury later in life]
A benign fibrous tumor may accompany muscular torticollis, called _____ ____
Fibromatosis colli
The complexity of the neck is due in part to the fascial compartments. What are the 5 compartments?
Superficial fascia Investing layer Pretracheal layer Prevertebral layer Alar fascia and carotid sheath
What is the first “deep” fascial layer you encounter in the neck?
Investing layer
In what fascial compartment would you find the platysma m.?
Superficial fascia
In what fascial compartment/layer would you find the deep neck muscles?
Prevertebral layer
In what fascial layer of the neck would you find the esophagus, trachea, thyroid, and strap muscles?
Pretracheal layer
What type of fascia runs between the carotid sheaths?
Alar fascia
What is the function of the carotid sheath?
Surrounds and protects the great vessels and nerves in the neck as the head moves
There are 3 named zones of penetrating trauma. Define the boundaries of zone I and the structures that are included in that zone
Zone I = the horizontal area between the clavicle/suprasternal notch and the cricoid cartilage
Important structures: Thoracic outlet structures Cupola of lung Proximal common carotid a. Vertebral a. Subclavian a. Trachea Esophagus Thoracic duct Thymus
There are 3 named zones of penetrating trauma. Define the boundaries of zone II and the structures that are included in that zone
Zone II = area between the cricoid cartilage and the angle of the mandible
Important structures: Internal carotid a. External carotid a. Jugular vv. Pharynx Larynx Esophagus Recurrent laryngeal n. Spinal cord Trachea Thyroid Parathyroids
There are 3 named zones of penetrating trauma. Define the boundaries of zone III and the structures that are included in that zone
Zone III = area that lies between the angle of the mandible and the base of the skull
Important structures:
Distal extracranial carotid a.
Vertebral a.
Uppermost segments of jugular vv.
What landmark in the posterior cervical triangle exists halfway between the mastoid process and clavicle, serving as the outlet for the cutaneous branches of the cervical plexus?
Erb’s point
T/F: the bulk of nuchal innervation anterolaterally comes from Erbs point
True
What are some of the cutaneous nerves of the neck?
From Erb’s point: Great auricular n. Transverse cervical n. Supraclavicular n. Lesser occipital n.
Others include cutaneous branches of posterior rami C4-8, greater occipital n., and third occipital n.
What are the other 2 names for the transverse cervical a.?
Superficial cervical a. or cervicodorsal a.
[same names apply to corresponding vv.]
What nerve bundle emerges around the scalene musculature in the neck?
Brachial plexus
What is the most superficial vein in the posterior cervical triangle?
External jugular v.
The superficial temporal v. joins the _______ vein to become the ________ vein, which then splits again into anterior and posterior divisions
Maxillary; retromandibular
The superficial temporal v. joins the maxillary vein to become the retromandibular vein, which then splits again into anterior and posterior divisions. The anterior division of the retromandibular v. joins the _____ v., while the posterior division joins the _______ v.
Facial; posterior auricular
What n. sits on top of the anterior scalene m.?
Phrenic n.
What structures are encountered in superficial dissection of the posterior cervical triangle (prior to going through prevertebral layer of deep cervical fascia)?
Trapezius m. SCM External jugular v. Cervicodorsal v. Cutaneous n. branches: lesser occipital n, great auricular n, transverse cervical n., supraclavicular n.
What muscles and nerves are encountered in superficial dissection of the neck, once you have gone through the prevertebral layer of fascia?
Accessory n (CN XI) Dorsal scapular n. Nerve to levator scapulae Roots of brachial plexus Phrenic n. Scalene mm. Splenius capitis m.
What are the cutaneous nn. associated with the cervical plexus?
Great auricular n.
Lesser occipital n.
Transverse cervical n.
Supraclavicular nn
The phrenic nerve supplies ____ innervation to the ______
Motor; diaphragm
T/F: the C1 root of the cervical plexus blends with and becomes a part of the hypoglossal n.
False - C1 components adhere to the hypoglossal n. but remain independent of it
They later differentiate into the ansa cervicalis and other muscular branches
Loop of nerves from the cervical plexus that carry somatomotor innervation to most of the infrahyoid muscles in the neck
Ansa cervicalis
What muscles are supplied by the ansa cervicalis?
Geniohyoid m. Thyrohyoid m. Omohyoid m. Sternothyroid m. Sternohyoid m.
What is contained within the carotid sheath?
Common carotid a. (bifurcates within sheath into external and internal carotid aa.)
Internal jugular v.
Vagus n.
Cervical LNs
In the deep suprahyoid region: what 3 cranial nerves arise posterior to the external carotid a. at the level of the auricle?
Spinal accessory n. (XI)
Glossopharyngeal n. (IX)
Hypoglossal n. (XII)
What 3 infrahyoid mm are found in the pretracheal fascia in the anterior triangle overlying the larynx?
Sternohyoid m.
Thyrohyoid m.
Omohyoid m.
What suprahyoid muscle is divided into anterior and posterior bellies, connecting to the hyoid via a fascial sling at its intermediate tendon?
Digastric m.
Innervation of digastric m.
Anterior belly of digastric = trigeminal n. (mandibular division)
Posterior belly of digastric = facial n.
What suprahyoid m. is responsible for elevating the hyoid and the tongue?
Mylohyoid m.
Innervation of mylohyoid
Nerve to mylohyoid (from inferior alveolar n. which is a branch of trigeminal)
What suprahyoid m. is responsible for shortening the floor of the mouth?
Geniohyoid m.
Innervation of geniohyoid m.
C1 via the hypoglossal n.
What suprahyoid m. is responsible for depressing the mandible and steadying the hyoid?
Digastrics
What are the 3 suprahyoid mm?
Mylohyoid m.
Geniohyoid m.
Digastric m.
Action of sternohyoid and omohyoid
Depress and steady the hyoid
Action of sternothyroid
Depress hyoid and larynx
Actions of thyrohyoid
Depress hyoid
Elevate larynx
Innervation of sternohyoid and omohyoid
Ansa cervicalis
Innervation of sternothyroid
Ansa cervicalis
Innervation of thyrohyoid
C1 via the hypoglossal n.
What are the 4 anterior prevertebral mm?
Longus colli m.
Longus capitis m.
Rectus capitis anterior m.
Anterior scalene m.
All of the anterior prevertebral muscles (longus colli, longus capitis, rectus capitis anterior, and anterior scalene) share what action/
Flexion of the neck
Longus colli m. is an anterior vertebral m. that flexes the neck, as well as what other action when contracting unilaterally?
Rotates neck in opposite direction
5 lateral prevertebral mm.
Rectus capitis lateralis m. Splenius capitis m. Levator scapulae m. Middle scalene m. Posterior scalene m.
Action of rectus capitis lateralis m.
Flex and stabilize head
Action of splenius capitis m.
Laterally flex and rotate head to same side, bilaterally extend head
Action of levator scapulae m.
Elevate scapula and tilt glenoid cavity inferiorly
Action of middle and posterior scalene mm.
Flex neck laterally, elevate 2nd rib during inspiration
The thoracic outlet is the space between the _____ and ______. This narrow passageway is crowded with blood vessels, nerves, and muscles
Clavicle
First rib
3 types of thoracic outlet syndrome along with characterizing symptoms
Neurogenic: numbness of limb, pain, weakness
Vascular: weak pulse, blood clots, pallor, coldness
Nonspecific: pain in region
Potential causes of thoracic outlet syndrome
Poor posture Repetitive use (baseball pitching)
Tx for TOS
Physical therapy
Surgery (anterior scalene release)
Sympathetics in the root of the neck and prevertebral region are associated with what 3 ganglia?
Superior cervical ganglion
Middle cervical ganglion
Inferior cervical ganglion
[sympathetics going anywhere cephalad to the superior cervical ganglion are postsynaptic]
Which is more likely to be performed in emergent situations: cricothyrotomy or tracheotomy? Why?
Cricothyrotomy, because a tracheotomy has a high risk of hitting the thyroid or the variably-present thyroid ima artery, and there is a high risk of bleeding
The area where the right and left lobes of the thyroid meet is called the ____
Isthmus
What nerve runs just deep to the thyroid and is responsible for innervating laryngeal mm responsible for vocalization?
Recurrent laryngeal n.
Along with a hoarse voice, what other effect might paralysis of the recurrent laryngeal n. have?
Inability to close off the vocal folds leads to inability to perform valsalva maneuver, thus leading to difficulties with defecation, lifting heavy objects, etc.
The thyroid is drained by superior, middle, and inferior thyroid veins. The superior and middle thyroid veins drain into the _______v., while the inferior thyroid vv. drain into the ______ v. which drains into the superior vena cava
Internal jugular; left brachiocephalic
During either a tracheotomy or thyroidectomy, there is high risk of bleeding d/t extensive vascularization of the area. What anteriorly located artery must surgeons be aware might be present when performing this procedure? What does this artery branch off of?
Thyroid ima artery, typically branches off the brachiocephalic trunk
Can also branch from the aortic arch, right common carotid, subclavian, or internal thoracic aa.
Blood supply to the thyroid includes the superior and inferior thyroid arteries. The superior thyroid a. is a branch of the ______ a., while the inferior thyroid a. is a branch of the _____ a.
External carotid; thryocervical trunk (coming off right subclavian)
The vagus n. is closely associated with the thyroid gland in its descent. What is the difference between the right and left vagus n.?
The right vagus n. gives off the right recurrent laryngeal n. which loops around the right subclavian a. and ascends back up as the right vagus continues down
The left vagus n. loops around the aortic arch prior to ascending back up
What is the most frequent form of thyroid dysgenesis?
Ectopic thyroid = presence of thyroid tissue in locations other than the normal anterior neck region between the 2nd and 4th tracheal cartilages
T/F: those with ectopic thyroids do not have any thyroid tissue in the normal location
False; ectopic thyroid tissue often co-exists with a eutopic thyroid
Ectopic thyroid development often has to do with abnormal pharyngeal arch development. What are some common locations for ectopic thyroid tissue?
Intralingual Base of the tongue Sublingual Prelaryngeal Substernal (retrosternal)
What veins often serve as the entry point for central line placement, such as a pulmonary artery catheter?
Right or left subclavian v
Describe subclavian venous puncture procedure for central line placement
The needle punctures the skin near the center of the clavicle and is advanced medially toward the tip of the index finger until the tip enters the right venous angle, posterior to the SC joint
A needle and catheter may be inserted in the ______ v. for diagnostic or therapeutic purposes. The right side is preferred because it is usually larger and straighter
Internal jugular vein
Describe internal jugular venous puncture
During this procedure, the clinician palpates the common carotid a. and inserts the needle into the IJV just lateral to it at a 30 degree angle, aiming at the apex of the triangle between the heads of the SCM (in the lesser supraclavicular fossa)
The needle is then directed inferolaterally toward the ipsilateral nipple
What 4 cranial nerves are anatomically closely related to the pharyngeal constrictor mm., emerging from the skull very close to one another?
IX — glossopharyngeal
X — vagus
XI — spinal accessory
XII — hypoglossal
Jugular foramen syndromes can affect multiple combinations of cranial nerves leading to variable effects. What cranial nerves are affected in Collet-Sicard syndrome?
IX
X
XI
XII
Jugular foramen syndromes can affect multiple combinations of cranial nerves leading to variable effects. What cranial nerves are affected in Vernet syndrome?
IX
X
XI
Vernet syndrome affects cranial nerves IX, X, and XI. What are the signs/symptoms of this condition?
Loss of taste sensation in posterior 1/3 of tongue (d/t glossopharyngeal involvement)
Paralysis of vocal cords and palate, anesthesia of larynx and pharynx (d/t vagus involvement)
Ipsilateral trapezius and SCM weakness and atrophy (d/t spinal accessory involvement)
The carotid sheaths are formed by contributions from what 3 fascial layers in the neck?
Pretracheal
Prevertebral
Investing
