Triangles of the neck

Nerves of the cervical plexus

-Anterior rami of C1-C4. These nerves exit at what is called Nerve point.The superficial branches are responsible for sensory innervation and the deep branches (phrenic and ansa cervicalis) are responsible for motor functions. -Located anteromedialy to levator scapulae and deep SCM.

Submental Triangle

-Base is the hyoid bone -Apex is the mandibular symohysis -Lateral border is the anterior diagastric -Medial border is the midline -Contents: submental lymph nodes and small veins that unite to form the anterior jugular vein -The suprahyoid muscles : digastric (anterior belly) and mylohyoid (CNV), stylohoid (CN VII, and geniohyoid (CNXII)

Posterior triangle

-Base is the middle 1/3 of the clavicle -Posterior border is the anterior border of trapezius muscle -Anterior border is oosterior border of the SCM -Subdivided into 2 triangles by the inferior belly of the omohyoid muscle., supraclavicular and occipital triangles.

Submandibular (digastric) Triangle

-Bordered by 2 heads of the diagastric muscle and the margin of the mandible. -The floor is the mylohyoid, hypoglossus and the middle constrictor -The contents are the submandibular gland, facial artery and vein, submandibular lymph nodes(lower face and superficial ear regions) and nerver to the mylohyoid and CN XII

Carotid Triangle

-Borders omohyoid, posterior diagastric and SCM muscles -Contents are the carotid sheath (common carotid artery and its 2 branches, internal jugular vein, CN X), external carotid artery and some of its branches, CN XI and XII, ansa cervicalis which comes from C1-C3, thyroid gland and deep cervical lymph nodes.

Muscular Triangle

-Borders: superior belly of the omohyoid, anterior border of SCM and midline of neck. -Contents Infrahyoid muscles-omohyoid, sternohyoid, thyrohyoid and sternothyroyid. All innervated by the ansa cervicalis (C1-C3) EXCEPT thyroidhyoid which is innervated by C1 via CNXII. -Parathyroid and thyroid gland and thyroid cartilage also located in this triangle.

Ansa Cervicalis C1-C3

-C1 sends a single nerve fiber down to meet the hypoglossal nerve and part will stay with the hypoglossal nerve,but the other portion forms the superior root of the Anas cervicalis. The ansa is only the looping part where we find nerve fibers going to the infrahyoid muscles. -C2 and C3 gives us the inferior root of Ansa Cervivalis.

Cranial Nerves in the Anterior Triangle

-CNX=vagus -CN=acessory=SCM and traps -CNXII=hypoglossal=majority of tongue muscles

Occipital Triangle a division of Posterior triangle.

-Contents; occipital artery which is a bracnh of the external carotid artery. CN XI, Nerver point, Nerves to the muscles of the floor, transverse cervical artery. -Floor: Spenius capitis, levator scapulae, anterior and middle scalene.

Subclavian Vein Puncture

-Either L or R veins are used for central line placement. -Catheters (Swan‐Ganz) are placed to administer parenteral fluids, medication or to measure central venous pressure -Infraclavicular approach: place thumb on middle part of clavicle and index finger on the jugular notch -Needle punctures the skin just inferiorly to the thumb and is advanced towards the index finger. At that point the needle should have entered the venous angle close to the brachiocephalic vein. -Particular care must be taken not to pierce the pleura and lungs (pneumothorax) or the subclavian artery.

Internal jugular vein (IJV) Puncture and Right Cardiac Catheterization

-For therapeutic or diagnostic purpose such as pressure measurements of the right chambers of the heart -Puncture right IJV (straighter), to reachthe brachiocephalic vein then SVC -Palpate the right common carotid and insert the needle into the IJV just lateral to it at a 30 degree angle -Aim for the apex of the triangle formed by the sternal and clavicular heads of the SCM The needle must then be directed inferolaterally towards the ipsilateral nipple

Superficial Nerves of cervical plexus

-Lesser occipital: C2, skin of the neck and posterosuperior to the ear -Great auricular: C2 and C3, ascends over SCM towards lower part of parotid gland. Innervates the skin over the gland, mastoid process, interior ear and angle of the mandible to mastoid process. -Transverse cervical; C2 and 3, passes over SCM going anteriorly. Supplies skin of the anterior cervical region. -Supraclavicular: C3 and 4, over SCM and down . Supplies skin over the shoulder area.

CN XI injury

-Penetrative trauma, surgical procedures, tumors or cancerous cervical lymph nodes, fracture of jugular foramen -SCM: Unilateral lesions do not cause abnormal position of the head. Causes weakness in turning to the opposite side against resistance (flaccid paralysis). Bilateral will make it difficult to hold the head upright -Trapezius: Difficulty in raising arm above horizontal plain. Will not cause complete drooping of the shoulder. Not flaccid paralysis because also innervated by C3&4

Torticollis

-Shortening or contracting of the cervical muscles most commonly the SCM. Most common is "wry neck" caused by fibrous tissue tumor in the SCM. Causes head tilt toward injury and away form the affected side. -Could also be caused via damage of CNXI. -Cutting or releasing the inferior attachment of the SCM below the level of CNXI might be necessary to straighten the neck.

Deep Cervical Fascia

1) Investing 2) Muscular Pretracheal 3) Visceral 4) Prevertebral 5) Carotid sheath

Common carotid arterty

1. Internal carotid (noting we need to know for now) 2. External carotid Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial temporal Some Anatomist Like facts Some perfer Made Up Stories

Subclavian Artery

1. Thyrocervical 2. Vetebral

Spasmodic Torticollis

All these particular forms of dystonia are collectively called "torticollis" and "spasmodic" is the word used to describe it further.

Supraclavicular Triangle

Contents: -Subclavian vein and artery -Brachial plexus -Phrenic nerve -2 main branches of thyrocervical trunk: -Suprascapular and transverse cervical arteries

Anterior Triangle

Divided into left and right triangles with the midline of the neck as the divider. Base is margin of the mandible Posterior Border is the anterior border of SCM Anterior border is the midline of the neck Is subdivided into 4 smaller triangles>>> submental, submandibular, carotid and muscular.

Carotid Body

Is a chemorecceptor innervated mainly by CN IX and partly X also. Its stimulated by low levels of oxygen. It initiates a reflex which increases rate and depth of respiration, cardiac rate and blood pressure.

Deep Cervical Fascia

Prevertebral m. are responsible for holding the head straight up an bending and rotating it etc.

Subclavian Pulse

Subclavian artery is a branch of the brachiocephalic trunk on the right and a direct branch of the arch of the aorta on the left. To feel the subclavian pulse one must compress against 1st rib superoposteriorly to the clavicle.

Orientation

The neck is divided into anterior and posterior triangles by the sternocleodomastoind muscle (SCM).

Carotid Sinus

This is a dilation of the internal carotid artery that is responsible for detecting changes in blood pressure. Its innervated mainly by CN IX and partly X. For Baroreceptor pressure.