Head and Neck

Question 1

Why is the neck subdivided into triangles?

Answer 1

The divisions permit effective communication to occur between health care professionals about the location of palpable masses in the neck

Question 2

What are the borders of the Anterior Triangle?

Answer 2

Superior border is the inferior border of the mandible.
The medial border is the imaginary saggital line down the mid line of the body.
The posterior border is the anterior border of SCM.

Question 3

How are the muscles in this region of the neck divided?

Answer 3

They are divided in relation to the hyoid bone. There are 4 suprahyoid and 4 infrahyoid.

Question 4

What are the suprahyoid muscles and what is their innervation and function?

Answer 4

Anterior (mylohyoid nerve) and posteior belly Digastric (facial nerve), mylohyoid (mylohyoid nerve), genihyoid (C1- via hypoglossal nerve), stylohyoid (facial nerve).
LOOK AT AN IMAGE

They form the floor of the mouth and they elevate the hyoid and larynx in relation to swallowing.

Question 5

What are the infrahyoid muscles and what is their innervation and function?

Answer 5

Sternohyoid, Superior and inferior belly of Omohyoid,Sternothryoid, thyrohyoid.
Ansa Cervicalis C1-C3 supplies all but thyrohyoid which is supplied by the frist cervical spinal nerve which travels with the hypoglossal nerve.

They depress the hyoid and larynx during swallowing and speaking.

Question 6

What are the borders of the carotid triangle?

Answer 6

Superior border is the posterior belly of the digastric, Inferior border is the superior belly of the omohyoid and posterior border is the anterior margin of SCM

Question 7

What are the contents of the carotid triangle?

Answer 7

Common carotid artery (with carotid body and sinus), Internal jugular vein (central venous catheter can be placed here–> risk of pneumothorax) , Thyroid gland, larynx, pharynx, branches of the cervical plexus, hypoglossal and vagus nerve, deep cervical lymphnodes

Question 8

Where does the bifurcation of the common carotid artery occur?

Answer 8

In the carotid triangle, at the superior margin of the thyroid cartilage, at the level of C4.

Question 9

What is the carotid sinus?

Answer 9

It is a dilated portion of the CCA which contains baroreceptors. These barorecpetors are innervated by the glossopharyngeal nerve which detects changes in the pressure and feed this information to the medulla to regulate the blood pressure.

Question 10

What is the carotid body?

Answer 10

The carotid body are peripheral chemorecptors located at the bifrucation of CCA. They are highly sensitive of oxygen levels in the blood. Large falls in pp of oxygen stimulates increased breathing rate, heart rate and blood flow distribution (increasing flow to brain and kidney).

Question 11

Why is the bifrucation more prone to atheroma formation?

Answer 11

There is a dilated portion where the carotid sinus is. This produces turbulent flow, increasing risk of atheroma formation-internal carotid is particularly susceptible. A doppler study can be carried out to examine the extent of thickening. In severe cases, the artery can be opened, and the atheromatous tunica intima removed. This procedure is called a carotid endaterectomy.

Question 12

Define atheroma.

Answer 12

This is the accumulation of extra and intracellular lipid in the tunica media and intima of small and large arteries.

Question 13

Define atherscerolsis

Answer 13

Thickeing and hardening of arterial walls as a consequence of atheroma

Question 14

Define arterioscerlosis

Answer 14

Thickening and hardening of walls of arteries and arterioles as a result of diabetes or hypertension.

Question 15

Common places where atherosclerosis can occur and concequence

Answer 15

Common carotid bifrucation–> TIA (mini stroke, caused by temp disruption in blood supply to the brain, duration is shorter than a strok and resolves with in 24 hours) or stroke
Abdominal Aorta- AAA
Coronary Arteries- MI, heart attack
Popliteal artery- intermittent claudication

Question 16

What is a carotid sinus massage?

Answer 16

Rubbing the carotid sinus stimulates an area in the artery wall that contains nerve endings. These nerves respond to changes in blood pressure and are capable of slowing the heart rate. Carotid sinus massage will slow the heart rate during episodes of atrial flutter, fibrillation, and some tachycardias. The physician must be sure there is no evidence of blockage in the carotid artery before performing the procedure. Massage in a blocked area might cause a clot to break loose and cause a stroke.

Question 17

What are the borders of the submental triangle?

Answer 17

Inferiorly the border is the hyoid bone. Medial border is the imaginary saggital midline and the lateral border is the anterior belly of the digastric.

Question 18

What are the contents of the submental triangle?

Answer 18

Submental lymph nodes

Question 19

What are the borders of the digastric/submandibular triangle?

Answer 19

Superior borer is the body of mandible, anteriorly by the anterior belly of the digastric and posteriorly by the posterior belly of the digastric

Question 20

What are the contents of the digastric triangle?

Answer 20

Submandibular glands, submandibular lymph nodes, facial vein and facial nerve.

Question 21

What are the borders of the muscular triangle?

Answer 21

The medial border is the imaginary saggital midline, the lateral border is the superior belly of the omohyoid, the superior border is the hypoid bone and the inferiolateral border is the inferior portion of the SCM.

Question 22

What are the contents of the muscular triangle?

Answer 22

No vessels, Contains the infrahyoid muscle, phyrnx, thyroid and parathyroid glands.

Question 23

What are the borders of the Posterior triangle?

Answer 23

Anterior border is the posterior border of SCM, posterior border is the anterior border of trapezius, inferior border is the medial third of the clavicle.

The floor is formed by deep cervical fasica and it is covered by an investing layer of fascia

Question 24

What are the triangles in the posterior triangle?

Answer 24

Occipital triangle and subclavian triangle. They are divided by the inferior belly of the omohyoid.

Question 25

What are the muscles in the posterior triangle?

Answer 25

Omohyoid and trapezius
Anterior, middle and posterior scalene, levator scapulae and splenias captitis–> all enveloped in the paravertebral fascia and form the floor of the posterior triangle.

Question 26

What is the vasculature in the posterior triangle?

Answer 26

There is the EJV which lies quite superificially ( it is formed by the retromandibular and the posterior auricular vein). It pierces the investing fascia and empties in the subclavian vein (also in the triangle). The subclavian vein can also be used to put in a central venous catheter.
Transcervical and suprascapular veins.
The distal part of the subclavian artery which then turns into the axillary artery when it crosses the border of the first rib. Also the transcervical and suprascapular artery.

Question 27

What would happen if the EJV is ligated?

Answer 27

Lumen is maintained by the investing fascia, air is drawn in and enters the atria and ventricles and central cynosis results. To prevent this and eventual death place pressure on the wound to stop bleeding and entry of blood.

Question 28

What are the nerves of the posterior triangle?

Answer 28

Accessory nerve–> innervates the SCM, a superficial nerve can be injured.
Trunks of the brachial plexus
Cervical plexus–> phrenic nerve arises from this plexus and descends down paravertebral fascia to supply the diaphragm.

Question 29

What is fascia?

Answer 29

It is connective tissue found in the body. Its functions include enveloping organs so that they can move against each other (e.g. swallowing), separating the tissues of the body, form compartments, usually contains infection within fascial compartments and bind the tissues of the body together.

Question 30

What are the two types of fascia?

Answer 30

Superficial cervical fasica–loose connective tissue

Deep cervical fascia-dense irregular connective tissue

Question 31

What is loose connective tissue?

Answer 31

It has interlacing, loosely organized fibers,abundant blood vessels, and significant empty space filled with interstitial fluid. Its fibers run in random directions and are mostly collagenous, but elastic and reticular fibers are also present. It may also have a loose arrangement of collagenous and elastic fibers, scattered cells of various types; abundant ground substance.

Question 32

What is dense irregular connective tissue?

Answer 32

The bundles of collagen are densely packed but irregularly arranged, such that they are orientated in multiple directions. It contains fibroblast and some ground substance too

Question 33

What does the superficial cervical fascia contain?

Answer 33

Platysma (supplied by the cervical branch of the facial nerve), EJV (and other superficial veins), superficial lymph nodes, fat, neurovasculature.

Question 34

What fascia makes up the deep cervical fascia?

Answer 34

Investing fascia, paravertebral fascia, paratracheal fascia, carotid sheaths.

Question 35

How might the SCM be damaged in new borns?

Answer 35

In forceps delivery the SMC can be damaged by compression or by being pulled.

Question 36

How would a person with a dystonic

sternocleidomastoid muscle present?

Answer 36

Patients head would be tilted ipsilateral to the lesion, the rotation of the chin would be to the contralateral side. Presentation is known as torticollis. In newborns it is known as congenital muscular torticollis.

Question 37

Describe the investing fasica

Answer 37

It is the most superficial fasica. It envelops the SCM, trapezius and parotid glands.

Question 38

Describe the pertracheal fascia

Answer 38

It is anterior to the neck and it fuses with the percardium. It contains the containing the larynx and trachea, the thyroid gland, and the pharynx and esophagus.

Question 39

Describe the paravertebral fascia

Answer 39

It enclosed the vertebral column and associated muscles such as the scalene, levator scapulae, splenius capitis

Question 40

Describe the carotid sheath

Answer 40

The contents of the carotid sheath are :
Common carotid artery (which bifurcates within the sheath into the external and internal carotid arteries).
Internal jugular vein.
Vagus nerve.
Superior laryngeal nerve.
Cervical lymph nodes.
The carotid fascia is organised into a column, which runs from the base of the skull to the thoracic mediastinum and it fuses with the percardial sac

Question 41

What is a potential space with regards to fascial planes of the neck?

Answer 41

Usually the fascial compartments of the neck are very close to each other and there are no spaces between adjacent fascial compartments. However, blood from perforated vessles and pus from infection can collect in between the fascial plans and create a potential space which was not there before.

Question 42

What is the retropharyngeal space and the danger space

Answer 42

The retropharngeal space is posterior to the pretracheal layer and it extends from the base of the skull to a variable position between T1-T6 vertebral bodies. It is anterior to the danger space. The danger space is a potential space posterior to the retropharangeal space. It connects deep cervical spaces to the mediastinum at the diaphragm, hence it is a potential path for the spread of infection (like retropharngeal abscess) to the mediastinum.

Question 43

What are some complications of the retropharangeal abscess?

Answer 43

Complications can occur due to: mass effect (compression), rupture and/or spread of infection. Compression of oesophagus or trachea can cause dysphagia or odynophagia or breathlessness, stridor. It is close proximity of the carotid sheaths hence infection can infitrate and cause jugular venous thrombosis. Should infection spread through the paravertebral layer it can affect bone and cause osteomelytis. It can spread to the mediastunum too.

Question 44

What are the layers of the scalp?

Answer 44

S-SKin, containts hair follicles and sebacous glands
C-Connective tissue containing the nerves and vessels of the scalp
A-Apenorosis, dense connective tissue running from the frontalis muscle to the occipitalis
L-loose connective areolar tissue. Rich in GAGs and made of type1 and type2 collagen
P-periosteum

Question 45

What is the blood supply to the scalp?

Answer 45

Supratrochelar and supraocular arteries—> Branches of internal carotid (opthalmic branch)
Superficial temporal, posterior auricular and occiplital branches of the external carotid artery. The veins have the same names

Question 46

What are emissary veins?

Answer 46

They are valveless veins which connect the extracranial venous system with the intercranrial venous system. They serve as routes where infections are carried into the cranial cavity from the extracranial veins to the intracranial veins. Infection or inflammation of the cavernous sinus can cause damage to the cranial nerves which run through it.
Rupturing of emissary veins can cause a subdural hematoma.

Question 47

What are the branches of the external carotid artery.

Answer 47

Superficial temporal artery
Ascending pharyngeal artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular
Maxillary artery
Superior thyroid artery

Question 48

Why do deep lacerations of the scalp causes excessive bleeding?

Answer 48

Deep lacerations which go through the apenurosis of the scalp causes profuse bleeding as the wound is pulled one due to the opposing forces of the occipitalis and frontal muscle (sutures required) there are also numerous anatomoses present here which cause bleeding. The scalp does not undergo avascular necrosis as it recieves alternative blood supply from the medial meningeal artery (ophthalmic branch).

Question 49

What is the pterion?

Answer 49

A weakened region of the scalp at the junction where the frontal, parietal, sphenoid and temporal bone meet. The medial meningial artery is underneath it. Trauma to the pterion causes rupture of the medial meningeal artery and an extradural hematoma ( between the skull and the dura mater)

Question 50

What is the danger triangle of the face?

Answer 50

The blood supply to the nose means that there is a venous communication between the facial vein and the cavernous sinus via opthalmic veins . SO there is a posibility of retrograde infection to spread from the nasal ara to the bran causing a cavernous siunus thrombosis (affects structures which run through this), meningitis or brain abscess.
INfections can be introduces via laceration of the face or bursing of pimples in areas where the facial vein drains.

Question 51

Why are patients with thrombophlebitis of the facial vein at risk of cavernous sinus thrombosis?

Answer 51

Inflammation of the facial vein causes secondary thrombus formation where pieces of the infected clot may break off and produce thrombosis of the cavernous sinus.

Question 52

What are the branches of the thyrocervical trunk?

Answer 52

The thyrocervical trunk arises distal to the vertebral artery from the subclavian artery. Its branches include: The suprscapular artery, transverse cervical artery, ascending cervical artery and inferior thyroid artery.

Question 53

What is the course of the vertebral arteries?

Answer 53

Arises from the subclavian artery, travels through the transverse foramen of C6 vertebrae and proceeds superiorly through each cervical vertebrae foramen. Both vertebral arteries unite to form the basilar artery which connects to the circle of Willis which supplies the brain.