Triangular Compartments Of The Neck Flashcards
What is the innervation of the plastysma muscle and when is it seen?
It is innervated by a branch of the facial nerve (CN VII).
It is seen when contracted in activities such as shaving
Where are the vocal cords located?
At the level of the middle of the thyroid cartilage
Where is the laryngeal prominence (Adams apple) of the thyroid cartilage of the larynx located?
In the midline
Can be felt when looking up and palpating the neck from superior to inferior
Where is the cricoid cartilage located?
Immediately belo the laryngeal prominence, follow by the trachea
Where is the hyoid bone located?
About an inch above the thyroid cartilage
It can be felt in the angle between the chin and anterior part of the neck, at the level of the 4th cervical vertebra
What is unique about the hyoid bone?
It does not have any connections to the bony skeleton
I.e. It is maintained in position by muscle attachments
What is indicative of strangulation in forensics?
A broken hyoid bone
What is the most prominent muscle in the neck and from where does it extend?
The sternocleidomastoid m: from the mastoid process of the temporal bone to a sternal head on the manubrium and a clavicular head on the middle third of the clavicle
Where does the SCM produce movement?
At the cranio-vertebral joints
What are the actions of the SCM?
- Unilateral contraction rotates head sideways so that the ear approaches the should on the same side while the chin is turned toward the opposite side
- The bilateral contraction flexes the neck (main flexor of the neck)
What is the innervation of the SCM?
Ventral primary rami of c3-c4 and the spinal accessory nerve (CNXI)
What is torticolis? (Wry neck)
A slanting of the head most commonly cause by a fibrous tumor on the SCM or by damage toCNXI
What is the carotid tubercle and its significance?
The anterior tubercle of the transverse process of the 6th cervical vertebrae can be felt deep in the neck at the anterior border of the SCM
It is the point of preference for compressing the common carotid a. To stop bleeding
How many muscles innervate the hyoid bone and what innervate those muscles?
10 muscles innervated from CN V3, VII, and XII and the cervical plexus.
What are the suprahyoid muscles?
Post. Belly of the digastric
Stylohoid
Ant. Belly of the digastric
Mylohyoid
Geniohyoid
What suprahyoid muscles are innervated by the facial nerve (CNVII)?
Post. Belly of digastric and stylohyoid
What suprahyoid muscles are innervated by CN V3?
Anterior belly of digastric (the stylohyoid m divides where it intersects the digastric muscles)
Mylohyoid
What suprahyoid muscles are innervated by C1 from cervical plexus and the hyoglossus from CN XII?
The geniohyoid
What do the suprahyoid muscles do?
Elevate (and protract) the hyoid-laryngeal complex during swallowing.
What are the infrahyoid muscles and their actions?
- Sternohyoid m -lowers hyoid
- Thyrohyoid m - raises larynx
- Sternothyroid m - lowers larynx
- Omohyoid m - courses from the scapular notch to hyoid via two bellies
What innervates the infrahyoid muscles?
The cervical plexus (motor division)
What is the main function of the infrahyoid muscles?
Depress the hyoid bone-larynx during speaking and after swallowing.
What are the prevertebral muscles of the neck?
Anterior, middle and posterior scalene muscles
What nerve courses over the anterior scalene?
Phrenic
Where do the scalene muscles attach to?
To the tubercles of the transverse process of the cervical vertebrae and the first rib
What do the scalene muscles assist in?
In extreme inspiratory effort by elevating the first nod second ribs. When accompanied by labored breathing this is an indication of respiratory distress
What innervates the scalene muscles?
The ventral primary rami of the cervical spinal nerves
What is the attachment, action and innervation of the levator scapulae?
- Arises from the tubercles on the transverse processes of the upper 4 cervical vertebrae and inserts on the superior angle of the scapula
- Elevates the shoulder
- Ventral primary rami of the cervical spinal nerves (dorsal scapular nerve)
Where dos the common carotid arise from?
From the aortic arch on the left and the brachiocephalic trunk on the right.
Each bifurcate into an internal and external branch.
What does the internal carotid supply?
The brain
Note: it does not have any branches in the neck
What happens when there is disruption of the blood flow to the brain?
Causes unconsciousness in seconds and irreversible damage in minutes. Death occurs when the brain ceases functioning.
What are the branches of the external carotid in the neck?
Mnemonic: Some Anatomists like freaking out poor medical students
S: Superior thyroid artery A: Ascending pharyngeal artery L: Lingual F: Facial artery O: Occipital artery P: Posterior auricular artery M: Maxillary artery S: Superficial temporal artery
What does the superior thyroid artery supply and what branch does it have?
Supplies the thyroid gland and has a superior laryngeal branch that accompanies the internal laryngeal nerve of CNX to the larynx
What path does the facial artery take and what does it supply?
Passes across the submandibular gland.
Main supply to the face and lips. Ends as the angular artery at the medial angle of the eye.
What does the facial artery end as?
The angular artery
What is the path of the lingual artery and what does it supply?
Passes deep to the hyoglossus muscle to supply the tongue.
Note: can arise in common with the facial artery
Where does the ascending pharyngeal artery arise from and what does it supply?
From the carotid bifurcation.
Supplies part of the pharynx
What does the occipital artery supply?
The occipital region of the scalp
What does the superficial temporal artery supply?
Supplies the scalp and part of the face as a terminal artery
Clinical: important source of blood for skin flaps in facial reconstruction surgery.
What does the maxillary artery supply?
Structures in the infratemporal fossa
What is the path of the vertebral arteries to become the basilar artery and supply the circle of Willis?
Each arises from the subclavian and passes through the transverse foramin of the cervical vertebrae.
The vertebral arteries join to form the basilar artery and supply blood to the brain via the circle of Willis
What does the basilar artery supply in order to supply the brain?
The circle of Willis
What does the thyro-cervical trunk divide into? (Branch of the subclavian)
Into a suprascapular artery and a cervicodorsal trunk
Where does the internal jugular vein receive blood from?
The brin and delivers it to the superior vena cava.
It is joined by veins from the face, larynx, thyroid gland, etc.
Where does the external jugular vein arise from?
Near the angle of the mandible by the confluence of the retromandibular and the posterior articular vein.
When does the external jugular vein become prominent?
When venous pressure rises such as in CHF (congestive heart failure), the vein becomes prominent all along its course.
Note: it’s normally visible just above the clavicle
The external jugular vein drains most of the scalp via what vein?
The superficial temporal branch
Where does the external jugular vein terminate and what does it give off?
In the subclavian vein, near the termination it gives off subscapular and cervico-dorsal veins that parallel their respective arteries.
In what locations are lymph nodes not found?
There are no lymph nodes in the scalp and none in the face (except for around the parotid gland)
Where re the superficial cervical lymph nodes found?
Along the external jugular vein
Where does lymph from the scalp, face and neck drain into?
The superficial ring of nodes