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