Anterior Triangle of the Neck Flashcards
What divides the anterior and posterior triangles of the neck?
Sternocleidomastoid muscle.
What forms the anterior border of the anterior triangle?
“Imaginary” midline of the neck
What forms the posterior border of the anterior triangle?
Anterior border of the sternocleidomastoid muscle
What forms the base of the anterior triangle?
Mandible
What are the divisions of the anterior triangle?
- Submental
- Submandibular
- Carotid
- Muscular
What lies in the submental division?
- Submental lymph nodes
- Beginning of anterior jugular vein
What lies in the submandibular division?
- Submandibular salivary glands
- Submandibular lymph nodes
- Facial artery + vein
- Carotid sheath
- Hypoglossal nerve
What lies in the carotid division?
- Carotid sheath
- Branches of external carotid artery
- Internal jugular vein
- Hypoglossal, accessory, and vagus nerves
What lies in the muscular division?
- Sternohyoid and sternothyroid form floor where thyroid gland lies
- Larynx
- Trachea
- Oesophagus
What is this muscle? picture
Platysma
What is the origin of the platysma?
Fascia above pect. major and clavicle
What is the insertion of the platysma?
- Lateral neck
- Mandible
What is the innervation of the platysma?
Facial nerve (CN VII)
Where does the external jugular vein lie?
Anterior to sternocleidomastoid
(posterior triangle)
Where does the internal jugular vein lie?
Posterior to sternocleidomastoid
(anterior triangle)
What makes up the cervical plexus?
Anterior rami C1-4
Describe the cervical plexus/
- Joined loops
- Lie anterior to levator scapulae and scalenus medius
What covers the cervical plexus?
Pre-vertebral layer of deep cervical fascia
What type of innervation does the cervical plexus provide?
- Somatic motor and sensory
- Sympathetic
What are the sensory branches of the cervical plexus?
C1 - lesser occipital
C2 - great auricular
C3 - transverse cervical
C4 - supraclavicular
What are the motor branches of the cervical plexus?
- Nerve to SCM
- Nerve to levator scapulae
- Nerve to trapezius
- Phrenic nerve
- Nerve to sternohyoid, sternothyroid, and omohyoid
- Ansa cervicalis
- Nerve to thyrohyoid
- Nerve to geniohyoid
Define suprahyoid.
Between hyoid bone and skull/mandible
Define infrahyoid.
Between hyoid bone and sternum/thyroid cartilage
Name the suprahyoid muscles. picture
What is the function of the mylohyoid and digastric muscles?
Raise hyoid bone/depress mandible
What innervates the stylohyoid and the posterior belly of digastric muscle?
Facial nerve
What innervates the anterior belly of digastric and the mylohyoid?
Mandibular division of trigeminal nerve (CNV3)
Name the infrahyoid muscles. picture
What is the function of the infrahyoid muscles?
Depress hyoid bone/thyroid cartilage
What innervates the infrahyoid muscles?
- Ansa cervicalis
- Thyrohyoid innervated by C1 via hypoglossal nerve CNV12)
What makes up the common carotid artery?
- Left carotid artery from arch of aorta
- Right carotid artery from the brachiocephalic
What are the terminal branches of the common carotid artery?
- Internal carotid artery
- External carotid artery
What does the internal carotid artery supply?
Brain
What does the external carotid artery supply?
- Head
- Face
- Neck
The common carotid artery lies in a sheath with what else?
- Internal jugular vein
- Vagus nerve
What are the 3 anterior branches of the external carotid artery in the anterior triangle (superior to inferior)
- Facial artery
- Lingual artery
- Superior thyroid artery
What is the tenth cranial nerve?
Vagus nerve
What branches of the vagus nerve supply the muscles of the larynx?
- Left recurrent laryngeal
- Right recurrent laryngeal
What type of gland is the thyroid gland?
Endocrine
What is the function of the thyroid gland?
Regulates metabolic rate
What are the features of the thyroid gland?
- 2 lobes
- Isthmus
- Capsule
Where is the thyroid gland located?
From lamina of thyroid cartilage to 6th tracheal ring
Where is the isthmus located?
Over 2nd or 3rd tracheal ring?
Where are the parathyroid glands located?
Posterior surface of the thyroid gland
Describe the arterial supply to the thyroid gland?
- Superior thyroid artery
- Inferior thyroid artery
- One of each on both sides
What is the superior thyroid gland a branch of?
First anterior branch of the external carotid artery
What is the inferior thyroid gland a branch of?
Branch of the thyrocervical trunk of the subclavian artery
Describe the venous drainage of the thyroid gland.
- Superior thyroid vein
- Middle thyroid vein
- Inferior thyroid vein
- On both sides
What do the inferior thyroid veins drain into?
- Both L and R drain into the left brachiocephalic vein
Describe the position of the submandibular salivary gland.
- Inferior to mylohyoid
- Part in floor of mouth superior to mylohyoid
Where do the ducts of the submandibular salivary gland open?
Between first and second lower incisor (either side of frenulum)
What innervates the submandibular salivary gland?
CNV 7 (facial nerve)
