Posterior Triangle

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What anterior border of the posterior triangle?

SCM

What is the posterior border of the posterior triangle?

trapezius

What is the inferior border of the posterior triangle?

clavicle

What makes up the roof of the posterior triangle?

platysma muscle
investing layer of deep cervical fascia

What makes up the floor of the posterior triangle?

splenius capitus
levator scapulae
scalene muscles (posterior, middle, and anterior)

What fascia covers the muscles that make up the floor of the posterior triangle?

deep cervical fascia

What are the origins of the SCM?

sternal head - manubrium
clavicular head - medial 1/3 of clavicle

What are the insertions of the SCM?

mastoid process and lateral 1/2 of superior nucchal line

What are the unilateral functions of the SCM?

tilts head toward shoulder on same side (lateral flexion)
rotates the head so the face turns to the opposite side

What are the bilateral functions of the SCM?

flexion of the cervical vertebrae when the person is supine

What nerves innervate the SCM?

accessory (XI)

What are the proximal attachments of the Trapezius?

external occipital protuberance, nuchal ligament

What are the distal attachments of the Trapezius?

clavicle, spine of scapula, acromion, C7-T12 spinous processes

What are the functions of the trapezius?

elevation, retraction, and depression of scapula

What nerve innervates the trapezius?

accessory nerve (XI)

What are the proximal attachments for the scalene muscles (superior, middle, inferior)?

transverse processes of cervical vertebrae

What is the insertion DA of the anterior scalene muscle?

1st rib

What is the insertion DA of the middle scalene muscle?

1st rib

What is the DA of the posterior scalene muscle?

2nd rib

What are the functions of the longus coli + scalenes + SCM?

flexion of neck

What is the bilateral function of the scalenes?

inspiration/elevation of ribs 1-2

What is the unilateral action of the intertransverse and scalene muscles?

lateral flexion of neck

What nerve innervates the scalenes?

ventral rami of cervical nerves

What muscle(s) can be found within the posterior triangle?

omohyoid muscle

What arteries can be found within the posterior triangle?

Third part of subclavian artery and its branches (dorsal scapular a., transverse cervical a., suprascapular a.)

What veins are found in the posterior triangle?

External jugular vein and subclavian vein (including transverse cervical v. and suprascapular v.)

What nerves are within the posterior triangle?

-Erbs Point (posterior edge of scalene)
-Roots and trunks of brachial plexus (and branches)
-Phrenic nerve
-CN XI

Axons of the spinal accessory nerve (XI) leave the spinal cord, join together, and ascend as a single nerve through what foramen in the skull?

foramen magnum

What foramen of the skull does the spinal accessory nerve (XI) leave the skull through?

jugular foramen

What muscles does the spinal accessory nerve (XI) innervate?

SCM
trapezius

Where do afferent fibers of the spinal accessory nerve (XI) go following the SCM and trapezius?

they return to the spinal cord between C2 and C4

The brachial plexus innervates the upper limb. What are the five parts of the brachial plexus?

roots, trunks, divisions, and branches
(mnemonic: roger travis drinks cold beer)

What parts of the brachial plexus lie within the posterior triangle?

roots and trunks

What are the five roots of the brachial plexus formed by?

the ventral rami of C5-T1

The roots of the brachial plexus form the three trunks. What is the superior trunk formed by?

the ventral rami of C5 and C6

The roots of the brachial plexus form the three trunks. What is the middle trunk formed by?

central ramus of C7

The roots of the brachial plexus form the three trunks. What is the inferior trunk formed by?

ventral rami of C8 and T1

The cervical plexus is the ventral rami of which cervical nerves?

1-4

The cervical plexus branches into 4 cutaneous nerves. List them

Lesser occipital nerve
Great auricular nerve
Transverse cervical nerve
Supraclavicular nerve
(mnemonic: Lets Go To School)

What area of skin does the supraclavicular nerve innervate?

skin of upper chest to shoulder

What area of skin does the transverse cervical nerve innervate?

skin of anterior triangle

What area of skin does the great auricular nerve innervate?

skin of ear and parotid region

What area of skin does the lesser occipital nerve innervate?

skin of ear and scalp

All nerves of the cervical plexus contains fibers from C2 and C3, except one. What is the exception?

supraclavicular nerve, which contains fibers from C3 and C4

What is the "nerve point of the neck"?

Erb's point

Where is Erb's point? What is it clinically useful for?

superior to the midpoint of the posterior border of the SCM
can be used to accomplish regional anesthesia of the skin and neck

Where does the external jugular vein begin?

near the angle of the mandible just inferior to the auricle of the external ear

What two veins does the external jugular form from near the angle of the mandible?

retromandibular vein and posterior auricular vein

Describe the course of the external jugular vein

From its origin, it crosses the SCM and then pierces the deep cervical fascia at the posterior border of the SCM. From there, it descends the inferior part of the lateral cervical region

Where does the external jugular vein terminate?

subclavian vein

The external jugular may serve as an internal barometer for measuring venous pressure. When venous pressure is in the normal range, the EJV is usually visible above the clavicle for only a short distance. What happens when venous pressure rises?

the EJV is prominent all along its course

What can cause venous pressure to rise?

heart failure, SVC obstruction, enlarged supraclavicular lymph nodes, or increased intrathoracic pressure

If the EJV is severed where it pierces the roof of the posterior triangle, its lumen will be held open by the investing layer of deep cervical fascia and negative intrathoracic pressure will suck air into the vein. What is produced? What is the result? Ho

A venous air embolism
dyspnea and cyanosis
application of firm pressure to the severed EJV until it can be sutured

What are the boundaries of the interscalene triangle?

anterior + middle scalene muscles and rib 1

What are the contents of the interscalene triangle?

brachial plexus and subclavian artery
note it does not contain the subclavian vein

What syndrome results from compression of the subclavian artery and/or brachial plexus in the interscalene triangle?

anterior scalene syndrome

What does compression of the subclavian artery in anterior scalene syndrome lead to?

compression of the subclavian artery leads to ischemia in the upper limb

What does compression of the brachial plexus in anterior scalene syndrome lead to?

the lower trunk of the brachial plexus will be elevated and compress the nerve fibers, causing pain, paresthesia, and muscle weakness

What rare anatomical anomaly will cause anterior scalene syndrome?

cervical rib

What muscle is the key muscle in the root of the neck due to its anterior relationships with the subclavian vein, phrenic nerve, external jugular vein, cervicodorsal trunk, sternocleidomastoid?

anterior scalene muscle

What nerve can be blocked with anesthetic or crushed on the anterior sclane muscle to achieve paralysis of the hemidiaphragm?

phrenic neve

What vein is often the point of entry to the venous system for central line placement?

subclavian vein

What can happen if the needle is not correctly inserted into the subclavian vein?

it may puncture the pleura, leading to pneumothorax, or it may puncture the subclavian artery

Why is the right subclavian vein preferable over the left to use for central line placement?

the thoracic duct is located on the left near the subclavian, so the right is desirable to use to avoid the thoracic duct

The subclavian artery is divided into three parts based on its relationship to the anterior scalene muscle. What are the three parts?

transverse cervical artery
suprascapular artery
left subclavian artery

What is the left subclavian artery named after it crosses the first rib? Where does it go from there?

the axillary artery
to the upper limb

Which layer of the deep cervical fascia fits the following description?
is the most superficial layer. It forms a tubular sleeve (called an investment) around the neck. It splits to enclose the sternocleidomastoid and trapezius.

investing layer

Which layer of the deep cervical fascia fits the following description?
covers the prevertebral muscles (longus colli and others), continues laterally and posteriorly to cover the scalene muscles and the levator scapulae muscles

prevertebral layer

Which layer of the deep cervical fascia fits the following description?
divided into two components, which together form a tubular sleeve around the cervical viscera (trachea, esophagus, thyroid gland).

visceral layer

What are the two layers of the visceral layer of the deep cervical fasica?

pretracheal fascia
buccopharyngeal fasica

Which layer of the visceral layer of the deep cervical fascia fits the following description?
forms a sheath around the entire thyroid gland.

pretracheal fascia

Which layer of the visceral layer of the deep cervical fascia fits the following description?
fascia connects the two lobes of the thyroid gland and covers the posterior surface of the esophagus

buccopharyngeal

What tubular sheath encloses the common carotid artery medially, the internal jugular vein laterally, and the vagus nerve posteriorly?

carotid sheath

What lies just outside the carotid sheath?

the sympathetic trunk

What is the most important fascial space in the neck?

retropharyngeal space

What is the anterior border of the retropharyngeal space?

buccopharyngeal fascia

What is the posterior border of the retropharyngeal space?

prevertebral fascia

What is the lateral border of the retropharyngeal space?

carotid sheath

Why is the retropharyngeal space clinically important?

it provides a route for the spread of infection from things such as an abscessed tooth to spread to the retropharyngeal space and into the chest

What is the extent of the retropharyngeal space?

it extends vertically from the base of the skull to the posterior mediastinum

What is the retropharyngeal space filled with? Why?

filled with loose areolar tissue to allow the pharynx and esophagus to expand when swallowing

What condition is a contraction of the cervical muscles that produces twisting of the neck and slanting of the head? It is caused by an injury to the sternocleidomastoid muscle when an infant's head is pulled too much during a difficult birth, tearing its

Torticollis