Chapter 20: Anatomy of the Neck - Key Terms and Definitions (Biology)

where is the neck?

region of the body between head and thorax

how many bones does the neck have?

8 bones

how many cervical vertebrae does the neck have?

7

CV1=ATLAS & CV2=AXIS

CV3-CV6

CV7= VERTEBRA PROMINENS

what is the eighth bone of the neck?

hyoid bone

where is the hyoid bone located?

lies in the anterior portion of the neck between the mandible and the larynx

what shape is the hyoid bone?

U shaped

where is the opening of the hyoid bone located?

posteriorly

what does the hyoid bone present anteriorly?

body

what does the body of the hyoid project posteriorly?

larger greater horns and smaller lesser horns

does the hyoid bone articulate with any other bone?

no

how is the hyoid bone suspended?

by the attaching muscles

what is the larynx?

voice box - a cartilaginous organ

where is the larynx located?

at the upper end of the trachea

what does the larynx consist of? which is the largest?

several cartilages (largest = thyroid cartilage)

what is another name for trachea?

windpipe

what is the trachea?

a cartilaginous pipe extending from the larynx above inferiorly through the neck into the thorax

what are the two glands of the neck?

1. thyroid gland

2. parathyroid gland

what/where is the thyroid gland?

endocrine gland just below the larynx, on either side of the trachea

what does the thyroid gland consist of?

2 lobes connected across the trachea by the isthmus

what/where is the parathyroid gland?

2-4 endocrine glands located on the posterior surface of the thyroid gland

the thyroid and parathyroid glands are both supplied by what?

superior and inferior thyroid arteries

what are the muscles of the neck?

1. Platysma (subcutaneous muscle)

2. Sternocleidomastoid

3. Infrahyoid muscles

4. Suprahyoid muscles

5. Scalene muscles

6. Prevertebral muscles

Platysma (subcutaneous muscle) Origin

Skin over the deltoid and pectoralis major muscles

Platysma (subcutaneous muscle) Insertion

lower border of the mandible

Platysma (subcutaneous muscle) Action

elevation of the skin of the neck

Platysma (subcutaneous muscle) innervation

CN VII; Facial nerve

Sternocleidomastoid Origin

1. Sternal head= manubrium of sternum

2. Clavicular head= medial 1/3 of the clavicle

Sternocleidomastoid Insertion

Mastoid process of the skull

Sternocleidomastoid Action

1. Unilateral= Rotation of head to opposite side

2. Bilateral= flexion of head at neck

Sternocleidomastoid Innervation

CN XI; Accessory nerve

What are the infrahyoid muscles (strap muscles)?

1. thyrohyoid

2. sternohyoid

3. sternothyroid

4. omohyoid

what is the origin of the thyrohyoid?

thyroid cartilage

what is the insertion of the thyrohyoid?

hyoid bone

what is the action of the thyrohyoid?

1. elevation of the larynx during speech & swallowing

2. depression of the hyoid during speech and swallowing

what is the innervation of the thyrohyoid?

C1 via CNXII (hypoglossal nerve)

what is the origin of the sternohyoid?

manubrium of sternum

what is the insertion of the sternohyoid?

hyoid bone

what is the action of the sternohyoid?

depression of the larynx and hyoid during speech and swallowing

what is the innervation of the sternohyoid?

ansa cervicalis

what is the origin of the sternothyroid?

manubrium of the sternum

what is the insertion of the sternothyroid?

thyroid cartilage

what is the action of the sternothyroid?

depression of the larynx and hyoid during speech and swallowing

what is the innervation of the sternothyroid?

ansa cervicalis

what is the origin of the omohyoid?

superior border of the scapula

what is the insertion of the omohyoid?

hyoid bone

what is the action of the omohyoid?

depression of the larynx and hyoid during speech and swallowing

what is the innervation of the omohyoid?

ansa cervicalis

what are the suprahyoid muscles?

1. digastric

2. stylohyoid

3. mylohyoid

4. geniohyoid

what are the scalene muscles?

1. scalene anterior

2. scalene medius

3. scalene posterior

what is the origin of the scalene anterior?

cervical vertebrae

what is the insertion of the scalene anterior?

first rib

what is the action of the scalene anterior?

1. lateral flexion of the neck

2. elevation of the first rib

what is the innervation of the scalene anterior?

ventral rami

what is the origin of the scalene medius?

cervical vertebrae

what is the insertion of the scalene medius?

first rib

what is the action of the scalene medius?

1. lateral flexion of the neck

2. elevation of the first rib

what is the innervation of the scalene medius?

ventral rami

what is the origin of the scalene posterior?

cervical vertebrae

what is the insertion of the scalene posterior?

second rib

what is the action of the scalene posterior?

1. lateral flexion of the neck

2. elevation of the second rib

what is the innervation of the scalene posterior?

ventral rami

what is ANTERIOR to the scalene anterior?

-phrenic nerve

-vagus nerve

-common carotid and internal carotid arteries

-internal jugular vein

-subclavian vein

what is POSTERIOR to the scalene anterior?

subclavian artery and brachial plexus

what is the scalene triangle?

1. scalene anterior (anterior boundary)

2. scalene medius (posterior)

3. first rib (inferior)

What are the prevertebral muscles?

longus capitis and longus cervicis (colli)

what are the nerves of the neck?

CERVICAL PLEXUS, VAGUS NERVE (CN X), AND SYMPATHETIC TRUNK!

what is the cervical plexus?

spinal nerve plexus formed by the ventral rami of C1 to C4

how is the cervical plexus arranged?

the plexus is arranged as an irregular series of loops from which the branches of the plexus arise

what do the branches of the cervical plexus supply?

scalene and prevertebral muscles

what are the two named branches that are given off (of the cervical plexus)?

phrenic nerve and ansa cervicalis

where does the phrenic nerve arise from?

ventral ramus C4 (C3,C5)

what does the phrenic nerve course?

1. through the neck anterior to scalene anterior

2. through the thorax anterior to the root of the lung

how many muscles does the phrenic nerve innervate?

1 muscle

what muscle does the phrenic nerve innervate?

diaphragm

what is the ansa cervicalis?

loop of nervous tissue that lies anterior to the carotid sheath

how many roots does the ansa cervicalis have?

two roots- the superior and inferior roots

what does the superior root of ansa cervicalis connect to?

hypoglossal nerve (CN XII)

what is the superior root of ansa cervicalis derived from?

C1

what is the inferior root of the ansa cervicalis derived from?

C2 and C3

what does the ansa cervicalis supply?

all the infrahyoid muscles except for the THYROHYOID

what are the superficial branches of the cervical plexus?

LET OUR GOALIE ALWAYS TAKE CARE SHOTS

lesser occipital (C2,C3)

greater auricular (C2,C3)

transverse cervical (C2,C3)

supraclavicular (C3,C4)

what do the superficial branches of the cervical plexus do?

provide cutaneous supply to the neck region and superior chest

what is the vagus nerve?

CN X

where does the vagus nerve arise from?

it arises from the brain and courses through a foramen in the base of the skull

where does the vagus nerve course (its path)?

courses from base of skull --> through the neck in the carotid sheath --> through the thorax posterior to the root of the lung --> through the esophageal opening of the diaphragm and enters the abdomen

what does the vagus nerve supply?

the abdominal organs

what is the sympathetic trunk part of?

part of the autonomic nervous system

where is the sympathetic trunk located?

in the neck - posterior to the carotid sheath

what are the vessels of the neck?

1. common carotid arteries and their branches

2. subclavian arteries and their branches

3. subclavian veins

4. jugular veins

what are the branches of the aortic arch?

1. brachiocephalic trunk

2. left common carotid artery

3. left subclavian artery

what does the branchiocephalic trunk divide into?

1. right subclavian artery

2. right common carotid artery

what do the subclavian arteries supply?

upper limbs

what do the carotid arteries supply?

head and neck

where does the right common carotid artery arise from?

brachiocephalic trunk

where does the left common carotid artery arise from?

arch of aorta

what does each common carotid artery ascend through?

the neck in its respective carotid sheath

where does each common carotid artery terminate?

the upper border of the respective side of the thyroid cartilage by dividing into its terminal branches

what are the terminal branches of the common carotid artery?

internal carotid and external carotid arteries

what does the internal carotid artery ascend within?

its respective carotid sheath

where does each internal carotid artery enter?

the cranial cavity through the carotid canal to supply the brain