lecture 22 neck and triangles

cervical vertebrae and musculature

the neck is supported by...

IX-XII

the neck contains cranial nerves...

stacked mobile column

7 cervical vertebrae form a...

significant rotational movement

C1 (atlas) and C2 (axis) are uniquely structured to permit...

transverse foramina, anterior and posterior tubercles of transverse processes, uncinate processes, and bifid spinous process

what are the common features of C3-C7 vertebrae?

spinous process of axis, spinous process of C7 vertebrae

list the posterior (palpable) landmarks

vertebrae prominens

what is the spinous process of C7 called?

C7 vertebrae

what spinous process is palpable at the base of the flexed neck?

U-shaped bone that does not articulate with other osseous structures

describe hyoid bone

directly inferior to the mandible at the C3 level

where is the hyoid bone located?

superior prominence of the thyroid cartilage

what is the laryngeal prominence?

anterior to C4 vertebrae

where is the laryngeal prominence located?

ring-shaped piece of hyaline cartilage directly inferior to thyroid cartilage

what is the cricoid cartilage?

C6 vertebrae

the cricoid cartilage lies at the....

inferior border of laryngopharynx and transition from larynx to trachea

what does the inferior margin of the cricoid cartilage correspond to?

sternocleidomastoid m

what muscle divides the neck into anterior and posterior cervical triangles?

inferior to mastoid process and posterior to angle of mandible

describe location of transverse process of atlas (C1 vertebrae)

external occipital protuberance, acromion process and lateral portion of clavicle

the trapezius muscle forms a muscular ridge from the ____ to the ___

either side of suprasternal notch

where is the tendon of the sternal head of sternocleidomastoid m located?

between the 2 tendons of SCM

where is the lesser supraclavicular fossa found?

inferior portion of internal jugular v

what does the lesser supraclavicular fossa overlie?

subclavian a

what does the supraclavicular fossa overlie?

SCM, transverse process of atlas, trapezius m, tendon of sternal head of SCM, tendon of clavicular head of SCM, lesser supraclavicular fossa, supraclavicular fossa

list landmarks of lateral neck

fascia and fascial compartments limit the spread of infections

what is the clinical significance of cervical fascia?

superiorly or inferiorly

within a fascial compartment of the neck, infection can only spread how within a single compartment?

the pathogen can degrade collagenous tissue

within a fascial compartment of the neck, infection can only spread superiorly or inferiorly within a single compartment, unless...

superficial cervical fascia (aka cervical subcutaneous tissue) and deep cervical fascia

how can cervical fascia be divided?

superficial cervical fascia (aka cervical subcutaneous tissue)

what layer of fascia is platysma embedded within?

investing fascia, pretracheal fascia, prevertebral fascia, alar fascia and carotid sheath

list types of deep cervical fascia

encircles neck deep to superficial fascia

describe investing fascia

occipital bone, mastoid process, zygomatic arches, inferior border of mandible, hyoid bone

what are the superior attachments of investing fascia?

manubrium, clavicle, acromion and spine of scapula, ligamentum nuchae

what are the inferior attachments of investing fascia?

SCM and trapezius mm

investing fascia splits into superficial and deep layers to enclose...

embryonic origins and innervation

SCM and trapezius share...

muscular portion and visceral portion

what is pretracheal fascia subdivided into?

anterior portion of neck, encircling infrahyoid and suprahyoid mm

where is the muscular portion of pretracheal fascia found?

larynx, pharynx, trachea, esophagus, thyroid gland, parathyroid glands, recurrent laryngeal nn, associated vessels

what does the visceral portion of the pretracheal fascia encircle?

visceral compartment of neck

the visceral portion of pretracheal fascia encircling the larynx, pharynx, trachea, esophagus, thyroid gland, parathyroid glands, recurrent laryngeal nn, and associated vessels forms what?

base of skull and hyoid to fibrous pericardium

pretracheal fascia extends from ____ to ____ creating a column

carotid sheaths

what does the pretracheal fascia fuse with laterally?

prevertebral mm, vertebral column, intrinsic musculature of neck, proximal portions of dorsal and ventral rami of cervical spinal nn

what does the prevertebral fascia encircle?

vertebral compartment (c)

the prevertebral compartment encircling the prevertebral mm, vertebral column, intrinsic musculature of neck, and proximal portions of dorsal and ventral rami of cervical spinal nn forms what compartment?

vertebral compartment (l)

what is the largest compartment of the neck?

endothoracic fascia, cervical portion of sympathetic trunk

inferiorly, the prevertebral fascia blends with the ____ and encases the ____

axillary sheath

what does the prevertebral fascia extend laterally to form?

brachial plexus and axillary a

what does the axillary sheath enclose?

common carotid a, internal carotid a, internal jugular v, and vagus n

the carotid sheaths are a pair of bilateral tubular fascial structures that enclose the...

investing fascia (cs)

what do the fibers of the carotid sheath blend with anterolaterally?

pretracheal fascia (cs)

what do the fibers of the carotid sheath blend with anteromedially?

alar fascia (cs)

what do the fibers of the carotid sheath blend with medially?

prevertebral fascia (cs)

what do the fibers of the carotid sheath blend with posteriorly?

two carotid sheaths

what does the alar fascia connect?

visceral and vertebral compartments of the neck

the alar fascia subdivides the space between the...

potential space between pretracheal fascia and alar fascia

what is the retropharyngeal space?

skull to superior mediastinum

the retropharyngeal space extends from the ___ to the ___

retropharyngeal space

what permits movement of the contents of the visceral compartment?

potential space between alar fascia and prevertebral fascia

what is the alar (danger) space?

laterally and inferiorly to the level of the diaphragm

infection in the alar space may spread...

less than one once

the thyroid gland is a small endocrine gland, normally weighing...

larynx

the thyroid gland is located in the front of the neck just below the...

trachea

the thyroid gland is shaped like a butterfly with two wings that lie along the...

isthmus

what is the narrow band of thyroid tissue that joins the two lobes of the thyroid gland?

isthmus (p)

if an ancillary lobe known as pyramidal lobe exists on the thyroid gland, where does it typically originate?

simple cuboidal cells called follicular cells

the thyroid gland is composed of spherical follicles formed by...

thyroid hormones T3 (triiodothyronine) and T4 (thyroxine)

what do the follicular cells of the thyroid gland produce?

colloid of follicle

where are thyroid hormones T3 (triiodothyronine) and T4 (thyroxine) stored?

hypothalamus and anterior lobe of pituitary gland

the production of thyroid T3 (triiodothyronine) and T4 (thyroxine) is controlled by a complex endocrine reflex involving the...

virtually all tissues (cytoplasmic, mitochondrial, and nuclear receptors)

T3 and T4 bind to intracellular receptors located in...

increase in ATP production and transcription and translational activities of cell

what does T3 and T4 binding to intracellular receptors cause?

clear cells or C cells

what are parafollicular cells aka?

release calcitonin to modulate plasma Ca++ concentration when it is elevated

what is the function of parafollicular cells (clear cells or C cells)?

autoimmune conditions

what is the most likely cause for thyroid gland dysfunction in North America?

when antibodies to TSH receptors are produced

when does Grave's disease occur?

over-secretion of T3 and T4 and hyperplasia of follicular cells, leading to diffusely enlarged thyroid gland

what does the inflammatory response trigger in Grave's disease?

when anti-T4, anti-thyroid peroxidase, anti-TSH receptor, and anti-thyroid antibodies are produced, leading to under-secretion of thyroid hormones and gradual destruction of thyroid gland

when does Hashimoto's thyroiditis occur?

1. high

2. low

3. low

list levels in primary hypothyroidism

1. TSH

2. fT4

3. fT3

1. low or normal

2. low

3. low

list levels in secondary hypothyroidism

1. TSH

2. fT4

3. fT3

1. low

2. high

3. high

list levels in primary hyperthyroidism

1. TSH

2. fT4

3. fT3

1. normal/high

2. high

3. high

list levels in secondary hyperthyroidism

1. TSH

2. fT4

3. fT3

enlargement of thyroid gland

what does the term goiter refer to?

diffuse bilateral goiter and exophthalmos

what are two common signs of Grave's disease

1. Trapezius m.

2. midline of body or sternohyoid m

3. clavicle

4. mandible

when side of neck is viewed as rectangle what is it bounded by

1. posteriorly

2. anteriorly

3. inferiorly

4. superiorly

anterior and posterior triangle

what does sternocleidomastoid m divide the neck into?

head with the thorax

the anterior triangle of the neck contains structures connecting the...

head to upper limb

the posterior triangle of the neck contains structures connecting the...

a superior occipital triangle and inferior supraclavicular triangle

what does the inferior belly of the omohyoid divide the posterior triangle into?

carotid and muscular triangle

what does the superior belly of the omohyoid divide the inferior part of the anterior triangle into?

submandibular and submental triangle

what does the digastric m divide the superior part of the anterior triangle into?

1. anteriorly sternocleidomastoid m

2. posteriorly trapezius m

3. inferiorly inferior belly of omohyoid m

occipital triangle borders

external jugular v, accessory n, supraclavicular nn, levator scapulae m, anterior, middle, and posterior scalenes

occipital triangle contents

1. superiorly inferior belly of omohyoid m

2. anteriorly

sternocleidomastoid m

3. inferiorly medial portion of clavicle

supraclavicular (omoclavicular) triangle borders

portion of brachial plexus, subclavian a, suprascapular a

supraclavicular (omoclavicular) triangle contents

1. superiorly

posterior belly of digastric m

2. posteriorly

sternocleidomastoid m

3. inferiorly superior belly of omohyoid m

carotid triangle borders

common carotid a, internal carotid a, external carotid a, internal jugular v, hypoglossal n, vagus n

carotid triangle contents

1. superiorly inferior border of mandible

2. anteriorly anterior belly of digastric m

3. posteriorly posterior belly of digastric m

submandibular triangle borders

submandibular gland, portion of facial a,v, stylohyoid m, mylohyoid m and n to mylohyoid m

submandibular triangle contents

1. superiorly anterior belly of digastric m

2. anteriorly median plan of neck

3. inferiorly hyoid bone

submental triangle borders

anterior jugular v, mylohyoid m

submental triangle contents

1. superiorly superior belly of omohyoid m

2. anteriorly median plane (medial border of sternothyroid m and sternohyoid m)

3. inferiorly sternocleidomastoid m

muscular triangle borders

sternothyroid and sternohyoid mm

contents of muscular triangle