Neck anatomy

Question 1

Superior boundary of the neck

Answer 1

Pericraniocervical line Inferior mandible and base of the skull

Question 2

Inferior boundary of the neck

Answer 2

Manubrium, clavicle and acromion to C7 spinous process

Question 3

Suprahyoid muscles

Answer 3

Mylohyoid

Digastric

Stylohyoid

All elevate the hyoid bone

Question 4

Infrahyoid muscles

Answer 4

Omohyoid
Sternohyoid
Scalene muscles (anterior, middle, posterior)
Thyrohyoid
Sternothyroid

Depress the hyoid bone, supplied by ansa cervicalis (C1-C3)

Question 5

Label the muscles of the anterior neck

Answer 5

Question 6

Posterior muscles of the neck

Answer 6

Levator scapulae - elevates shoulders (dorsal scapula nerve, C3 and C4)

Splenius capitis, semispinalis capitis - flex and extend the neck and head (posterior rami of spinal nerves)

Suboccipital muscles: extend the head on C1, rotate the head on C2 (C1 posterior ramus)

Ligamentum nuchae - strong median ligament of the neck.

Question 7

Compartments of the neck

Answer 7

Four comparments enclosed by an outer musculofascial collar (investing fascia)

1. Vertebral compartment (cervical vertebrae and postural muscles). Covered by prevertebral fasia
2. Visceral compartment (glands - thyroid, parathyroid, thymus). Covered by pretracheal fascia
3. Vascular compartment x 2(carotid vessels and vagus nerve). Covered by carotid sheaths

Question 8

Borders of the anterior triangle of the neck

Answer 8

Medial: midline

Lateral: sternocleidomastoid

Superior: inferior margin of mandible

Question 9

Borders of the posterior triangle

Answer 9

Medial: sternocleidomastoid

Lateral: trapezius

Base: clavicle

Apex: mastoid process

Question 10

Subdivisions of the anterior triangle

Answer 10

Question 11

Contents of the carotid triangle

Answer 11

Carotid, thyroid, facial & lingual arteries

Internal jugular & facial veins

CN X, XI, XII, VII

Superior laryngeal nerve

Thyroid gland

Question 12

Which landmarks would you use to locate the common carotid pulse?

Answer 12

Common carotid artery lies in a groove between the trachea and infrahyoid muscles.

Palpated deep to anterior border of sternocleidomastoid at the level of the thyoid cartilage

Question 13

Contents of the submandibular triangle

Answer 13

Submandibular lymph nodes

Submandibular salivary gland

Hypoglossal nerve

Lingual artery

Facial artery & vein

Marginal mandibular branch of CN VII

Question 14

Contents of submental triangle

Answer 14

Submental lymph nodes

Anterior jugular vein tributaries

Question 15

Subdivisions of the posterior triangle

Answer 15

Divided by omohyoid muscles into occipital triangle and supraclavicular triangle

Question 16

Fascia of the neck

Answer 16

Superficial fascia of the neck contains a thin sheet of muscle (platysma) which begins in the thorax and runs upwards to the mandible

Deep fascia is organised into layers.
Investing layer - completely surrounds the neck

Prevertebral layer - surrounds vertebral column and muscles (prevertebral, scalene muscles, depe muscles of the back)

Pretracheal layer - surround the trachea, oesophagus and thyroid. hyoid bone to upper thoracic cavity

Carotid sheath - surround common carotid, internal carotid, internal jugular vein, vagus nerve. Sympathetic chain lies posterior to sheath

Question 17

Fascial spaces in the neck

Answer 17

Prevertebral space - between investing layer of the cervical fascia and pretracheal fascia. Passes between the neck and anterior part of the superior mediastinum

Retropharyngeal space - between the buccopharyngeal fascia (part of pretracheal) and prevertebral fascia. Extends from the base of the skill to upper part of the posterior mediastinum.

Question 18

Retropharyngeal space

Answer 18

Between buccopharyngeal fascia (pretracheal) and prevertebral fascia. Extends from the base of the skull to posterior mediastinum.

Alar fascia crosses the retropharyngeal space.

Consists of loose connective tissue. Permits movement of the pharynx oesophagus and larynx during swallowing.

Major pathway for the spread of infection

Question 19

Spread of infection in the neck

Answer 19

Investing layer of deep cervical fascia helps prevent the spread of absesses.

If an infection occurs between the investing layer and pretracheal fascia the infection does not spread beyond the manubrium.

If infection occurs between the investing fascia and the visceral part of the pretracheal fascia it can spread into the thoracic cavity anterior to the pericardium.

Question 20

Buccopharyngeal fascia

Answer 20

Posterior part of the pretracheal fascia. Separates the pharynx and the oesophagus from the prevertebral layer.

Begins at the base of the skull and ends in the thoracic cavity.

Question 21

Axillary sheath

Answer 21

Prevertebral fascia of the neck that extends from the anterior and middle scalene muscles to surrounds the brachial plexus and subclavian artery as they pass into the axilla.

~ In axilla, axillary sheath contains 1st part of axillary artery, axillary vein and cords of the brachial plexus.

N.B. Infection in the vertebral compartment can spread to the upper limb via the axillary sheath

Plexus block via injection is done via the axillary sheath.

Question 22

Central lines

Answer 22

Lesser supraclavicular fossa used to access internal jugular vein - space between the origin of the two heads of sternocleidomastoid

Question 23

Contents of the supraclavicular/omoclavicular triangle

Answer 23

Subclavian artery and vein

Supraclavicular nodes

Suprascapular nerve

Question 24

Points where brachial plexus can be anaesthatised

Answer 24

Supraclavicular triangle

Axillary sheath

Interscalene (anterior and middle)

Question 25

Floor of posterior triangle

Answer 25

Formed by prevertebral facia overlying muscles of the neck Splenius capitus Levator scapulae Scalenes Inferior belly of omohyoid

Question 26

Nerves in the posterior triangle

Answer 26

Phrenic nerve Brachial plexus Acessory nerve Doral scapular nerve Long thoracic nerve

Question 27

Superficial drainage of the neck

Answer 27

External jugular veins and anterior jugular veins Exernal jugular vein is formed by post auricular and retromandibular vein. Runs from the angle of the mandible diagonally across sternocleidomastoid to the lateral point where it meets the clavicle. It then pierves the investing and enters the subclavian vein. Anterior jugular veins are paired venous channels that drain the anterior aspect of the neck. They begin as small veins descend on either side of the midline. Each anterior vein pierces the investing facia to enter the subclavian vein. Connected by a jugular venous arch at the suprasternal notch.

Question 28

Lymph nodes in the head and neck

Answer 28

Submental - lower lip, tip of tongue Submandibular - lip, lateral body of tongue, nose, face Parotid (preauricular): temporal scalp and eye Mastoid: external acoustic meatus and pinna Occipital: occipital scalp to vertex Superficial cervical: runs with external jugular vein Jugulo-digastric: tonsil, pharynx, posterior tongue Deep cervical chain: superficial node groups Jugulo-omohyoid: superficial node groups, central tongue Supraclavicular: surround thoracic duct,

Question 29

Describe the origin and course of the carotid arteries

Answer 29

Common carotid: Right common carotid - originates from the brachicephalic trunk. Left common carotid - direct branch of the arch of the aorta that pases into the neck. Both pass superiorly into the neck at the sternoclavicular joint and ascend lateral to the trachea and oesophagus within the carotid sheath. Divide into the external and internal carotid arteries at the thyroid cartilage (C3/C4 vert.) Internal carotid arteries: ascend towards the base of the skill and enters the cranial cavity through the carotid canal. Supplies cerebral hemispheres, eyes and forehead External carotid arteries give off branches immediately after the bifurcation to supply the neck and face.

Question 30

Describe the distribution of the branches of external carotid arteries

Answer 30

External carotid arteries give off branches immediately after the bifurcation of the common carotid arteries 1. superior thyroid - supplies thyroid gland, larynx, muscles (TH, SCM) 2. ascending pharyngeal artery - pharyngeal constrictors, palate, tonsil, pharyngotypmanic tube 3. lingual artery - musles of the tongue, palatine tonsil, soft palate, floor of the mouth, sublingual gland 4. facial artery - structures of the face 5. occiputal artery - SCM, deep muscles of the back, scalp 6. posterior auricular artery - parotid and surrounding muscles, exernal and inner ear 7. superficial temporal artery - parotid, masseteer, temoporalis, external ear 8. maxillary artery - EAM, middle ear, mandible and maxilla (skin, gums, teeth), nasal cavity

Question 31

Mylohyoid

Answer 31

Support and elevation of the flood of the mouth Elevation of hyoid CN V3

Question 32

Digastric

Answer 32

Lowers mandible to open mouth, raises hyoid bone and pulls is back Anterior belly: CN V3 Posterior belly: CN VII

Question 33

Omohyoid

Answer 33

Depresses and flexes hyoid bone Ansa cervicalis (Anterior rami C1-)

Question 34

Stylohyoid

Answer 34

Pulls hyoid bone posterosuperiorly CN VII

Question 35

Sternohyoid

Answer 35

Depresses hyoid bone after swallowing Ansa cervicalis (C1-C3)

Question 36

Sternothyroid

Answer 36

Draws larynx/thyroid cartilage downwards Ansa cervicalis

Question 37

Scalene muscles

Answer 37

Anterior, middle elevate rib 1 posterior elevates rib 2 Anterior rami C3-C7

Question 38

Thyrohyoid

Answer 38

Depresses hyoid bone, raises larynx when hyoid is fixed C1

Question 39

What key structures present at the bifurcation of the common carotid?

Answer 39

Carotid sinus contained in the dilation of the common carotid at point of bifurcation. Contains receptors that monitor changes in bp. Innervated by glossopharyngeal nerve (CNIX) Carotid body detect changes in pO2 and pCO2. Innervated by branches of CNIX and CNX