Sem 2 - O - Anterior triangle of the neck - Boundaries, Divisions, Fascia, Cervical Plexus, Hyoid muscles, Nerves, Arteries, Glands Flashcards
Which structures divides the neck into anterior and posterior triangles?
The sternoclediomastoid divides the neck into anterior and posterior triangles
What forms the borders of the anterior triangle of the neck?
Anterior triangle borders
- Anterior border - imaginary midline of the neck
- Posterior border - anterior border of the sternoclediomastoid
- Base (superior) - mandible
The anterior triangle of the neck can be separated into divisions
- * Sub-mental
- * Sub-mandibular
- * Carotid
- * Muscular
Which structures are found within the sub-mental division of the anterior triangle of the neck?
Within the submental divison -
- * the submental lymph nodes and
- * the beginning of the anterior jugular vein are found
Which structures are found within the sub-mandibular division of the anterior triangle of the neck?
Within the Submandibular division -
- * Submandibular lymph nodes
- * Submandibular salivary gland
- * Facial artery and vein
- * Carotid sheath
- * Hypoglossal nerve
- * And more
Which structures are found within the carotid division of the anterior triangle of the neck?
Within the cartoid divsion -
- * Carotid sheath
- * Branches of ECA
- * Internal jugular vein
- * Hypoglossal, accessory and vagus nerves
- * And more
Which structures are found within the muscular division of the anterior triangle of the neck?
Within the muscular division - Sternhyoid and sternothyroid muscles beneath which lies the thyroid gland, larynx, trachea and oesophagus
Which structures form the floor of the anterior triangle of the neck?
The sternohyoid and sternothyroid muscles form the floor of the anterior triangle of the neck
Name the structures found in each of the divisions of the anterior triangle of the neck
- * Sub-mental
- * Sub-mandibular
- * Carotid
- * Muscular
- Sub-mental - submental lymph nodes and the beginning of the anterior jugular vein
- Submandibular - submandibular lymph nodes and salivary glands, facial artery/vein,carotid sheath hypoglossal nerve etc
- carotid sheath, branches of ECA, internal jugualr vein, hypoglossal, accessory and vagus nerves
- Muscular - sternothyroid and sternohyoid forms the floor, beneath which lies thyroid gland, trachea, larynx&oesophagus
What is the cutaneous muscle located directly deep to the skin and superficial fascia of the neck? Which triangle of the neck is this muscle located in?
This would be the platysma The platsyma is located in the anterior and posterior triangles of the neck
The platysma is classified as one of the muscles of facial expression
What is the attachment of the platsyma? What is the nerve supply to the platysma?
Attachment - from fascia above pectoralis major and clavicle to the lateral neck and onto the mandible Small slips form up onto the face above the mandible
Nerve supply - facial nerve (CN VII)
- Which fascial layer of the neck surrounds the platysma?
- Which fascial layer surrounds the trapezius and SCM muscles as well as all other fascial compartments of the neck?
- Which fascial encloses the internal jugular vein, common carotid arteries, vagus nerves and deep cervical lymph nodes?
The investing fascia of the neck will lie deep to the superficial fascia of the neck surrounding the platsyma, trapezius and sternocleidmastoid muscles as well as enclosing all other fascial compartments of the neck
The carotid sheaths enclose the internal jugular vein, common carotid arteries, vagus nerves and deep cervical lymph nodes
Which fascial layer is deep to the investing fascia, located posteriorly and surrounds the cervical vertebrae and postural neck muscles?
Which fascia layer is deep to the investing fascia, located anteriorly and surrounds the supra/infrahyoid muscles, thyroid gland, trachea, larynx, oesophagus?
The prevertebral fascia of the neck is located deep to the investing fascia surrounding the cervical vertebrae and postural neck muscles
The pretracheal fascia of the neck is located deep to the investing fascia surrounding the supra/infrahyoid muscles, thyroid gland, trachea, larynx and oesophagus
Lets talk about the superficial vessels of the neck How is the external jugular vein formed?
The superficial temporal and maxillary veins join anterior to the ear to form the retromandibular vein
The posterior auircular vein (draining the scalp superior and posterior to the ear) will join the posterior division of the retromandibular vein to form the external jugular vein
Where does the external jugular vein travel? What happens to the anterior division of the retromandibular vein?
The external jugular vein runs anterior to the sternocleidomastoid and into the posterior triangle of the neck where it will eventually drain into the subclavian vein
The anterior division of the retromandibular vein joins with the facial vein to form the common facial vein which drains into the internal jugular vein
What muscle does the IJV run beneath? Where does it drain to?
What is the formed in the imaginary midline of the neck that is not always present in the population? Where does it drain?
The internal jugular vein runs deep to the SCM and drains into the brachiocephalic vein
The anterior jugular vein is formed in the midline of the neck from superficial veins at the submental region. It travels laterally to go deep to the SCM and into the external jugular vein in the posterior triangle of the neck
What are the nerve roots of the cervical plexus? What are the nerve roots of the brachial plexus?
Nerve roots of the cervical plexus - Anterior rami of C1-C4
Nerve roots of the brachial plexus - anterior rami of C5-T1
What fascia of the neck covers the nerve roots of the cervical plexus? What modalities does the cervical plexus carry? Which triangle of the neck is the cervical plexus located within?
The cervical plexus is covered by the prevertebral fascia layer of deep fascia of the neck
It carries somatic motor and sensory (plus sympathetic) fibres
The cervical plexus is located in the posterior triangle of the neck
What is the area known as where the cutaneous nerve branches from the cervical plexus enter the skin? Which cervical plexus root does not provide any sensory innervation?
The cutaneous nerves of the cervical plexus all enter the skin at the middle of the posterior border of the sternocleidomastoid muscles - this is known as Erb’s point C1 does not provide any sensory innvervation
What are the 4 nerves and their nerve roots providing cutaneous innervation that arise from the cervical plexus?
- * Lesser occipital nerve - C2
- * Great auricular nerve - C2,3
- * Transverse cervical nerve - C2,3
- * Supraclavicular nerves (medial, intermediate and lateral) - C3,4
What area do each of the cutaneous nerves of the cervical plexus innervate?
Lesser occipital (C2)-
- the skin of posterior superolateral neck and posterior to external ear
Great auricular (C2,3)-
- the skin of the external ear and the angle of the mandible
Transverse cervical (C2,3)-
- the skin of the anterolateral aspect of neck
Supraclavicular (C3,4)-
- the skin of the supraclavicular fossa & sternoclavicular jt.
We have now discussed the cutaneous branches of the cervical plexus (lesser occipital, great auricular, transverse cervical, supraclavicular)
Which muscles receive proprioceptive sensory fibres from the cervical plexus? (State nerve roots) State the motor nerve supply to both these muscles?
Sternoclediomastoid - proprioception from C2,3 anterior rami
Trapezius - proprioception from C3,4 anterior rami
Both these muscles receive motor innervation from the spinal accessory nerve (CN XI)
There are many motor branches going to the muscles from the cervical plexus Try name all the nerves and the muscles they will innervate from the cervical plexus
- * Nerve to geniohyoid
- * Nerve to thyrohyoid
- * Ansa cervicalis (superior/inferior belly of omohyoid, sternohyoid, sternothyroid)
- * Phrenic nerve (diaphragm)
- * Direct C3,4 and C5 from dorsal scapular nerve (levator scapulae)
- * Anterior rami C1-3 (longus capitis)
- * Anterior rami C2-6 (longus colli)
- Anterior rami C1,2 (Rectus capitis anterior & lateralis)
Which muscles does the cervical plexus lie anterior to? Which muscle does the cervical plexus emerge anterior to the midpoint of the posterior border?
The cervical plexus lies anterior to the middle scalene and levator scapulae and will emerge anterior to the midpoint of the posterior border of the sternocleidomastoid
What do the suprahyoid muscles run between?
What do the infrahyoid muscles run between? What are the infrayhoid muscles also known as?
The suprahyoid muscles run between the hyoid bone and the skull or mandible
The infrahyoid muscles aka the strap muscles, run between the hyoid bone and the sternum or thyroid cartilage
What are the four suprahyoid muscles? Which are able to depress the mandible?
Mylohyoid Geniohyoid Digastric Stylohyoid
The mylohyoid, anterior belly of digastric and the geniohyoid muscles are able to depress the mandible
`What are the attachments of the geniohyoid and what is its nerve supply? (What nerve does this travel on to reach the geniohyoid) Which muscles does geniohyoid lie posterior to?
The geniohyoid attaches from the inferior genial tubercle of the mandible to the hyoid bone It is innervated by the nerve to geniohyoid (C1) which travels with the nerve to thyrohyoid via the hypoglossal nerve Geniohyoid lies posterior to mylohyoid
What are the attachments of the digastric muscle?
Anterior belly of digastric - arises from the digastric fossa of the mandible
Posterior belly - arises from the mastoid process of the temporal bone
- The two bellies are connected by an intermediate tendon which attaches to the hyoid bone via a fibrous sling
What is the attachments and nerve supply to the digastric muscle?
Anterior belly - arises from the digastric fossa of the mandible - innervated by mandibular division of the trigmeinal nerve
Posterior belly - arises from the mastoid process of the temporal bone - innervated by the facial nerve
- Both bellies are connected via an intermediate tendon which is attached to the hyoid bone via a fibrous sling
STATE AGAIN THE SUPRAHYOID MUSCLE ATTACHMENTS AND THEIR INNERVATIONS
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Name the infrahyoid (strap) muscles? What is their function?
Omohyoid Sternohyoid Sternothyroid Thyrohyoid
Their function is to depress the hyoid bone/thyroid cartilage
STATE AGAIN THE INFRAHYOID MUSCLE ATTACHMENTS AND THEIR INNERVATIONS WHAT IS THEIR ACTIONS?
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How is the ansa cervicalis formed and what structure does this nerve run on top off?
The ansa is a loop of nerves that are part of the cervical plexus It is formed from from a superior root (from C1 fibres travelling via the hypoglossal nerve) and an inferior root (from C2 and 3 fibres) joining together
The nerve runs immediately on top of the carotid sheath
The CCA are contained within the carotid sheath. What else is in this tube?
The carotid sheath contains the * Common carotid artery * Vagus nerve (in the middle) * Internal jugular vein * and Lymphatics
Common carotid artery according to the textbooks has no branches except the terminal internal and external carotid arteries although sometimes ECA branches can come from CCA What is the arrow pointing to in the pic and where does it usually lie?
The arrow is pointing to the ansa cervicalis which usually lies anterior to the common carotid artery on top of the carotid sheath
In the anterior triangle of the neck of the neck, the three anterior branches of the ECA can be found What are these three branches?
We have the superior thryoid artery, the lingual artery and the facial artery
The subclavian artery gives branches deep in the triangles of the neck The subclavian artery can be divided into parts by which muscle? What are the parts?
- Part 1 - origin to medial border of anterior scalene muscle
- Part 2 - behind anterior scalene muscle
- Part 3 - between lateral border of anterior scalene muscle and lateral border of rib 1
What are the branches coming from the subclavian artery? (state which part)
VIT C D - mnemonic
- Part 1
- Vertebral artery
- Internal thoracic artery
- Thyrocervical trunk
- Part 2
- Costocervical trunk
- Part 3
- Dorsal scapular artery
What are the branches of the thyrocervical trunk and the costocervical trunk?
Thyrocervical trunk
- Inferior thyroid artery
- Ascending cervical artery
- Transverse cervical artery
- Suprascapular artery
Costocervical trunk
- Supreme intercostal artery
- Deep cervical artery
What branches does the vagus nerve give off before entering the carotid sheath?
Gives off superior laryngeal branches which divide to form internal and external laryngeal branches
What is usually the superior and inferior borders of the thyroid gland? What does the isthmus sit over? Where are the parathyroid glands?
The thyroid gland begins at the lamina of the thyroid cartilage to the 6th tracheal ring
The isthmus lies over tracheal ring 2 or 3
The 4 parathyroid glands are embedded on the posterior surface of the thyroid gland
What is the blood supply to the thyroid gland? State where the branches arise?
The superior thyroid artery is the first anterior branch of the ECA
The inferior thyroid artery is a branch of the thyrocervical trunk which is a branch of part 1 of the subclavian artery
What is the venous drainage of the thyroid gland?
Superior, middle and inferior thyroid veins on either side
- Superior and middle thyroid veins both drain into the internal jugular vein on either side
- The inferior thyroid veins both drain into the LEFT brachiocephalic vein
Where does the submandibular gland lie?
The superficial part of the submadinbular gland is inferior to the mylohyoid and the deep part is in the floor of the mouth superior to the mylohyoid
Where does the submandibular gland open and what is the nerve supply to the submandibular gland?
Submandibular glands have one duct for each which open between the first and second incisor either side of the frenulum
The gland is supplied by the chorda tympani branch of the facial nerve (CN VII)
The thoracic duct drains many local lymph nodes in the head and neck Where does it drain to?
Thoracic duct drains into the left venous angle between the left internal jugular vein and left subclavian vein
