Anatomy of neck

Question 1

LO’s

Answer 1

1. Demonstrate the boundaries of the anterior and posterior triangles of the neck defined by the
   sternum, clavicle, mandible, mastoid process, trapezius, sternocleidomastoid and the midline.
2. In the posterior triangle, demonstrate the position of the spinal accessory nerve, the roots and
   trunks of the brachial plexus, the phrenic nerve, the external jugular vein and subclavian vessels in relation to penetrating neck trauma.
3. Describe the courses of the accessory, vagus and phrenic nerves in the neck.

Question 2

Cranial nerves of the heck

Answer 2

1. Trigeminal CN 5
2. Facial CN 7
3. Glossopharyngeal CN 9
4. Vagus CN 10
5. Spinal Accessory CN 11
6. Hypoglossal CN 12

Question 3

Cervical fascia (4)

Answer 3

1. Investing layer
2. Prevertebal
3. Pretracheal
4. Carotid sheath

Question 4

Investing layer

Answer 4

• Surrounds neck like collar
• Encloses SCM, infrahyoid muscles and trapezius

Question 5

Prevertebral

Answer 5

Covers prevertebral muscles

Question 6

Pretracheal fascia

Answer 6

Lies deep to infrahyoid muscles

encloses thyroid, trachea and pharynx/ oesophagus

Question 7

Carotid sheath

Answer 7

Encloses vagus nerve, internal jugular vein, common and internal carotid arteries

Question 8

Tissue spaces of the neck- infection (2)

Answer 8

Prevertebral space-

between the prevertebral fascia and cervical vertebra

limited inferiorly at T4

Retropharyngeal space

Continuous soace from the base of the skull to the posterior mediastinum

Question 9

Triangles of the neck and their boundaries (2)

Answer 9

Anterior triangle-

imaginary line from mental protuberance to manubrium

Anterior border of SCM

Inferior border of mandible (1/2)

Posterior triangle-

Posterior border of SCM

Clavicle

Anterior border of trapezius

Question 10

What are some of the supferficial structures of the posterior triangle? (e.g., fascia and nerves)? (4)

Answer 10

1. Branch of Cervical plexus
2. Prevertebral fascia
3. Spinal accessory n (CN XI)- motor innervation to SCM and Trapezius
4. Investing fascia- split around SCM, trapezius and strap muscles

Question 11

Within the posterior triangle sits the cutaneous branches of the cervical plexus? ( 7)

Answer 11

1. Lesser occipital
2. Great auricular
3. Transverse cervical
4. Supraclavicular
5. Hypoglossal nerve
6. Ansa cervicalis
7. Phrenic

Question 12

What structures are found in the posterior triangle at the root of the neck? (4) e.g., nerves arteries

Answer 12

• Roots of brachial plexus
• Phrenic nerve
• Branches of the subclavian artery:

Suprascapular artery

Transverse cervical artery

• Apex of lungs

Question 13

Which muscles make up the floor of the posterior triangle? (6)

Answer 13

Prevertebral muscles:

1. Splenius capitus
2. Levator scapulae
3. Posterior scalene
4. Middle scalene
5. Anterior scalene
6. Omohyoid

Strap muscles:

1. Omohyoid

Question 14

What are the suprahyoid muscles of the anterior triangle? (5)

Which 2 nerves innervate these muscles? (2)

Answer 14

Suprahyoid

Innervated by CN V3 (mandibular division)

• Mylohyoid
• Anterior belly of digastric
• Geniohyoid

Innervated by CN 7

Stylohyoid

Posterior belly of digastric

Question 15

What are the infrahyoid muscles of the posterior triangle?

Which nerves innervate them? (2)

Answer 15

Infrahyoid mucsles innervated by Ansa cervicalis

• Sternohyoid
• Omohyoid
• Sternohyoid

Infrahyoid mucsles innervated by CN XII

Thyrohyoid

Question 16

Submandibular gland

Which muscle in the anterior triangle does it wrap around?

Which nerve does the submandibular duct cross superior to?

Which gland does the submandibular duct also receive secretions from?

Where does preganglionic innervation originate? Where does this synapse? Which nerve does the postganglionic pass through?

Answer 16

1. Submandibular gland wraps around mylohyoid muscle
2. Submandibular duct crosses superior to the lingual nerve
3. Submandibular duct also receives secretions from the sublingual gland
4. Preganglionic parasympathetic fibres from chorda tympani ( CN VII), synapses in submandibular ganglion, postganglionic via the lingual nerve

Question 17

External carotid artery

1. Which artery feeds this branch?
2. What are the branches of the ECA?

Answer 17

Common carotid –> (Int. Carotid A) + (Ext. Carotid A)

Branches of the ECA (from inferior to superior)

1. Superior thyroid
2. Ascending pharyngeal
3. Lingual
4. Facial
5. Occipital
6. Posterior auricular
7. Superficial temporal
8. Maxillary

Question 18

Anatomically the venous drainage of the head and neck can be divided into 3 groups what are they?

Answer 18

1. brain and meninges- via dural venous sinuses
2. scalp and face- veins synonymous with the arteries of the face and scalp. These empty into the internal and external jugular veins
3. neck- carried out by the anterior jugular veins

Question 19

Jugular veins

What are the 3 jugular veins?

What areas are they responsible for draining?

What branches form them?

What do they drain into?

Answer 19

External jugular vein-

• (+ its tributaries) drain the majority of the external face
• Formed from the posterior auricular (scalp posterior and superior to ear) and retromandibular vein (formed from maxillary and superficial temporal veins, which drain the face)
• Descends in the superficial fascia of the neck
• Drains into the subclavian vein

Question 20

Jugular veins

What are the 3 jugular veins?

What areas are they responsible for draining?

Answer 20

External jugular vein-

• (+ its tributaries) drain the majority of the external face
• Formed from the posterior auricular (scalp posterior and superior to ear) and retromandibular vein (formed from maxillary and superficial temporal veins, which drain the face)
• Descends in the superficial fascia of the neck
• Drains into the subclavian vein

Question 21

External Jugular vein

What does it drain?

Which branches form it?

What fascia can it be found in?

What does it drain into?

Answer 21

External jugular vein-

• (+ its tributaries) drain the majority of the external face
• Formed from the posterior auricular (scalp posterior and superior to ear) and retromandibular vein (formed from maxillary and superficial temporal veins, which drain the face)
• Descends in the superficial fascia of the neck
• Drains into the subclavian vein

Question 22

Anterior jugular veins

• How many are there
• What area do they drain
• Where do they travel
• what do they drain into

Answer 22

• 2- paired
• drain anterior neck
• descend down the midline of the nck
• empty into sublclavian vein

Question 23

Internal jugular vein

• What is it a continuation of
• How does it exit the skull
• What does it descend within
• What vein does it form?
• What veins does it receive blood from?
• What structrues does it drain?

Answer 23

• Continuation of sigmoid sinus
• leaves skull via jugular foramen
• descends within the carotid sheath
• combines with the subclavian vein to form the brachiocephalic vein
• receives blood from sigmoid sinus, facial, lingual, occipital, superior and middle thyroid veins

drains

• anterior face
• trachea
• thyroid
• oesophagus
• larynx
• muscles of the neck

Question 24

What does an elevated JVP suggest about the venous system?

Answer 24

elevated of JVP sign of venous hypertension

Question 25

Facts for jugular veins

Question 26

Cervical plexus

can be split into 3 groups

what are these groups and what to they innervate?

Answer 26

C1-4: sensory to skin over post scalp, anterior and posterior neck, skin superior and posterior to the ear

C1-3: ansa cervicalis, motor to most of the strap muscles

C3-5: phrenic nerve

Question 27

Hypoglossal nerve CN XII

Which spinal level is represented by CN XII?

Which 2 muscles does it innervate in the neck?

Which muscles does it inenrvate in the mouth?

Answer 27

• Innervation form branches of C1 carried in the hypoglossal
• Thyrohyoid (infrahyoid and strap muscle) and geniohyoid (suprahyoid muscle)
• Intrinsic and extrinsic muscles of the tongue

Question 28

Vagus nerve

Motor function in the head and neck

Sensory function to the larynx

Answer 28

motor- most of soft palate muscles and most of pharynx/ larynx muscles

Sensory- innervation to 4th arch structures

Question 29

Glossopharyngeal nerve CN IX

Sensory function

Motor function

Answer 29

Sensory-

• post 1/3 of the tongue (sensory)
• to pharynx (sensory limb of gag reflex)
• to inner surface tympanic membrane

Motor-

• stylopharyngeus
• parotid gland (parasympathetic)

Innervation to 3rd arch structures (embryology)

Question 30

Deep structures of the neck- sympathetic chain

What are the 3 sympathetic ganglia of the cervical chain?

Answer 30

• Superior cervical ganglion
• Middle cervical ganglion
• Inferior cervical ganglion