Unit I: Deep Structures of the Neck Flashcards
A dense, sheet-like layer of CONNECTIVE tissue
Fascia
This surrounds and supports BOTH the superficial and deep structures of the neck.
-It consists of TWO major layers (superficial and deep)
Cervical fascia
The two major LAYERS of the Cervical fascia
1) Superficial cervical fascia
2) Deep cervical fascia
A thin layer of CONNECTIVE tissue deep to the skin that encloses the:
- Platysma muscle
- contains cutaneous nerves
- contains superficial veins and lymph nodes
Superficial cervical fascia
Four layers of the Deep cervical fascia
1) Investing layer
2) Pretracheal fascia
3) Prevertebral fascia
4) Carotid sheath
Most superficial layer of the deep cervical fascia that lies deep to the superficial cervical fascia and splits to enclose the SCM and and trapezius
Investing layer of Deep cervical fascia
This layer of deep cervical fascia encloses the thyroid gland, trachea, and esophagus. It begins above as Buccopharyngeal fascia. Found in the Muscular triangle
Pretracheal fascia
This layer of the deep cervical fascia encloses the vertebral column and the deep muscles of the back. Contains the sympathetic trunk on the anterior surface.
Prevertebral fascia
This layer of deep cervical fascia is a cylinder of fascia that extends from the base of the skull to the root of the neck. It contains many important structures
Carotid Sheath
The contents of the Carotid sheath
1) Common Carotid artery
2) Internal Carotid artery
3) Internal Jugular vein
4) Vagus nerve
5) Deep cervical lymph nodes
This nerve is located below the internal jugular vein and the internal Carotid artery
Vagus nerve
This artery splits into two branches: the internal Carotid artery and the external carotid artery in the carotid triangle
Common carotid artery
These drain all the lymph from the head and neck
Deep cervical lymph nodes
This artery exits the Carotid sheath BEFORE giving off its branches in the neck
External Carotid artery
Functions of the Fascial layers
1) Provides a slippery surface to REDUCE friction during gross movements of head and neck and during swallowing
2) Adhesions can cause neck pain
The most common place for adhesions in the neck
Between the investing layer of the deep cervical fascia and the superficial cervical layer
Clinical significance of Fascial layers
1) May serve as a channel for INFECTION
- -Pretracheal fascia may allow an infection to spread from head and neck to mediastinum directly (fascia surrounding heart)
2) Cancer involving cervical lymph nodes can compress INTERNAL JUGULAR VEIN, which would INCREASE cranial pressure.
This is an opening through which structures of the neck pass INTO the THORAX.
Superior Thoracic Aperture (Thoracic Inlet)
Boundaries of the Superior thoracic aperture (thoracic inlet)
1) first thoracic vertebrae
2) First ribs and their cartilages
3) Manubrium of sternum
This structure is kidney-shaped
Superior thoracic aperture (thoracic inlet)
Major structures passing through the Superior thoracic aperture
1) Arteries
- Brachiocephalic trunk
- Left common carotid artery
- left subclavian artery
- Internal thoracic artery
2) Veins
- Brachiocephalic vein
3) Nerves
- Phrenic nerve
- Vagus nerve
- Recurrent pharyngeal nerve
- Sympathetic trunk
4) Viscera
- Trachea
- Esophagus
- Cervical pleura
- Apex of lung
- Thymus
This artery passes through the Superior thoracic aperture behind the brachiocephallic vein. It exits into the right subclavian and right carotid arteries
Brachiocephallic trunk
This nerve supplies the diaphragm
Phrenic nerve
This is the most important nerve of the larynx
Recurrent Laryngeal nerve
This visceral membrane of the thorax covers the apex of the lung
Cervical pleura
Why is there a potential for lung collapse and with neck injury?
The cervical pleura and apex of the lung pass through the superior thoracic aperture immediately POSTERIOR to the origin of the SCM. A broken 1st rib or penetrating wound of the neck may cause the lung to collapse
Name for when the lung collapses
Atelectasis
This structure is part of the immune system and produces T-lymphocytes. It is usually composed of two irregular lobes and lies primarily BEHIND the manubrium and body of sternum
Thymus
This structure can extend into the neck and around the front and sides of the trachea
Thymus
Lies INFERIOR to the thyroid gland
Thymus
The sternohyoid and sternothyroid muscles lie ANTERIOR to the_____ and thyroid gland
Thymus
Blood supply to the Thymus
Internal thoracic artery
Nerve supply to the Thymus
Stellate ganglion of the sympathetic trunk and vagus nerve
This is an endocrine organ that produces thyroxine and calcitonin.
Thyroid gland
This endocrine organ lies at the level of C5 to T1
Thyroid gland
The thyroid gland is U or H shaped and consists of three parts
1) Left lobe
2) Right lobe
3) Isthmus
This connects the left and right lobes of the thyroid gland and forms a bridge across the front of the trachea.
Isthmus
50% of thyroid glands have this, which extends upward from the isthmus as a finger of glandular tissue
Pyramidal lobe
This muscle connects the isthmus of the thyroid gland with the hyoid bone. It is associated with the thyroid gland.
Levator glandulae thyroideae muscle
Blood supply to the thyroid gland
Arteries 1) Superior thyroid artery 2) Inferior thyroid artery Thyroid Ima artery Veins 1) superior thyroid vein 2) middle thyroid vein 3) inferior thyroid vein
This gland is HIGHLY vascular
Thyroid gland
This is the most inferior branch of the external carotid artery and supplies the thyroid gland
Superior thyroid artery
This artery comes off of the thyrocervical trunk and supplies the thyroid gland
Inferior thyroid artery
This is an inconstant branch to the thyroid gland from the brachiocephalic trunk. It divides into right subclavian and internal carotid artery. Only present in 10% of the population. This could be damaged during a tracheotomy.
Thyroid Ima artery
This vein goes to the internal jugular vein and supplies the thyroid gland
Superior thyroid vein
This vein goes to the internal jugular vein and supplies the thyroid gland
Middle thyroid vein
This vein goes to the brachiocephalic vein (right side) and supplies the thyroid gland
Inferior thyroid vein
Nerve supply to the thyroid gland
Superior, middle, and inferior cervical sympathetic ganglia
An abnormal enlargement of the thyroid gland. It produces swelling in the ANTERIOR part of the neck. There are two types: Endemic and Exophthalmic
Goiter
This type of goiter is due to a dietary deficiency of IODINE (necessary to produce Thyroixine). The thyroid gland will enlarge to increase output and the hormone becomes highly INACTIVE. (treatable)
Endemic goiter
When the thyroid gland is INACTIVE due to an iodine deficiency. This can lead to Endemic goiter. Symptoms include:
- weight gain
- moon face
- tired all the time and cold
Hypothyroidism
This type of goiter is due to an AUTOIMMUNE disease (Goiter’s disease). The thyroid gland will become OVERACTIVE and will produce a lot of hormones.
Exophthalmic goiter
When the thyroid gland is HIGHLY overactive. This can lead to Exophthalmic goiter. Symptoms include:
- weight loss
- always hot and increased heart rate
- outward bulging of the eyes
Hyperthyroidism
An autoimmune disease that causes Exophthalmic goiter. Symptoms include fatty deposits behind the eyes causing the eyes to bulge. (Body attacks the thyroid gland)
Grave’s disease
This nerve branches off of the Vagus nerve WITHIN the thorax and then travels up the neck to supply MOTOR innervation to all but one of the laryngeal muscles.
Recurrent laryngeal nerve
Within the neck, this nerve is the first on the POSTERIOR surface of the thyroid lobe and then deep to the lobe.
Recurrent laryngeal nerve
These are endocrine glands that are involved in CALCIUM homeostasis and are ESSENTIAL to life
Parathyroid glands
There are 4 small ovoid bodies located on the POSTERIOR surface of the thyroid gland that can vary in number from 2 to 6.
Parathyroid glands
Blood supply to the Parathyroid glands
1) Inferior thyroid artery
2) superior thyroid artery
Nerve supply to the parathyroid glands
Inferior and middle cervical sympathetic ganglia
Factors contributing to the difficulty of thyroid surgery
1) Vascularity
2) Parathyroid glands
3) recurrent laryngeal nerve
This is the “windpipe” that begins at the larynx at the level of C6. Within the thorax it splits into the left and right main bronchi. Its walls are supported by a series of incomplete cartilaginous rings which open posteriorly
Trachea
The POSTERIOR gap of the trachea is spanned by the this smooth muscle and allows the EXPANSION of the esophagus during swallowing
Trachealis
Blood supply to the trachea
Inferior thyroid artery
Nerve supply to the trachea
Recurrent laryngeal nerve
This is a muscular tube that connects the pharynx to the stomach. It begins in the neck at C6 and lies POSTERIOR to the trachea (food tube)
Esophagus
The main arteries of the neck and head that are divided into left and right parts
Common Carotid arteries (left and right)
This artery ascends within the Carotid sheath to the carotid triangle (anterior triangle) where it splits into TWO branches.
Common carotid artery
Two branches of the Common carotid artery
1) internal carotid artery
2) external carotid artery
This branch of the common carotid artery has NO branches in the neck. It enters the skull through the carotid canal (in temporal bone) to supply blood to the brain.
Internal carotid artery
This branch of the common carotid artery is the MAIN source of blood to structures of the: -neck -face -scalp (structures EXTERNAL to skull) It has 8 branches
External carotid artery
8 branches of the external carotid artery
1) superior thyroid artery
2) ascending pharyngeal artery
3) lingual artery
4) facial artery
5) occipital artery
6) posterior auricular artery
7) superficial temporal artery
8) maxillary artery
The two terminal branches of the External carotid artery
1) superficial temporal artery
2) Maxillary artery
This branch of the external carotid artery goes up onto the face and to the lateral corner of the mouth. You can feel a pulse here.
Facial artery
This branch of the external carotid artery is located above the superior thyroid and supplies the tongue
Lingual artery
This branch of the external carotid artery runs to the occiput and supplies the back of the skull
Occipital artery
This branch of the external carotid artery runs BEHIND the ear and is located within the skull.
Posterior auricular artery
This branch of the external carotid artery is the most INFERIOR and supplies the thyroid
Superior thyroid artery
This is a slight dilation (bulging) of the internal carotid artery where it joins to form the common carotid artery.
Carotid sinus
This structure which is part of the internal carotid artery acts as a BARORECEPTOR (blood pressure sensor)
Carotid sinus
Innervation to the carotid sinus
Carotid sinus nerve
The carotid sinus nerve is a branch of this nerve
Glossopharyngeal nerve (C.N. IX)
A plaque buildup in this region could cause a stroke because there is no way to detect a change in blood pressure to the brain
Carotid sinus
This structure is a small reddish-brown mass located within or deep to the bifurcation of the common carotid artery.
Carotid body
This structure of the common carotid artery is a CHEMORECEPTOR which detects changes in the chemical makeup of the blood within the carotid
Carotid body
Innervation to the Carotid body
Carotid sinus (branch of glossopharyngeal N)
One of two of the major veins of the neck that is the LARGEST vein in the neck
Internal Jugular vein
This vein begins in the jugular foramen and is the DIRECT continuation of the sigmoid sinus.
Internal jugular vein
This vein drains into the brachiocephalic vein
Internal jugular vein
This is the dilation (bulging) of the internal jugular vein at its origin BELOW the jugular foramen
Superior jugular bulb
Tributaries of the Internal jugular vein
1) inferior petrosal sinus
2) Pharyngeal veins
3) Facial vein
4) Lingual vein
5) superior thyroid vein
6) middle thyroid vein
This is a dilation (bulging) of the internal jugular vein near its TERMINATION into the brachiocephalic vein. (It has a valve to keep blood moving towards heart and NOT back to the brain).
Inferior jugular bulb
