Anterior Triangle of the Neck Flashcards
What is this muscle?
Platysma
What are the infrahyoid muscles?
Omohyoid
Sternohyoid
Thyrohyoid
Sternothyroid
What runs within the carotid sheath?
Common carotid artery
Internal jugular vein
Vagus nerve
What are the branches of the common carotid arteries?
Internal carotid - runs to the brain
External carotid - supplies head, face and neck
What are the boundaries of the anterior triangle of the neck?
Anterior border = imaginary midline of the neck
Posterior border = anterior border of the SCM
Base = Mandible
What are the branches of the vagus nerve that supplies the structures of the neck?
Right and Left recurrent laryngeal branches
Left loops under the arch of the aorta
Right loops under the subclavian artery
What are the muscular relationships of the cervical plexus?
Lies anterior to the levator scapulae and scalenus medius
What is the role of the infrahyoid muscles?
Depress the hyoid bone and thyroid cartilage
What nerve supplies the submandibular gland?
CN VII (facial nerve)
What arteries are given off by the 1st part of the subclavian?
Vertebral branch to the brain
Thyrocervical trunk to structures of the neck
What is the arterial supply of the thyroid gland?
Superior thyroid - a branch of the external carotid artery
Inferior thyroid - a branch of thyrocervical trunk (from the subclavian)
Describe the attachments of mylohyoid
Attaches to the mylohyoid line of the mandible and to the hyoid bone
Forms a diaphragm on the floor of the oral cavity
True or False?
The suprahyoid muscles are commonly referred to as the strap muscles
False!
It is the infrahyoid muscles that are also known as the strap muscles
Between which veins does the thoracic duct empty lymph into the venous system?
At the junction of the Internal jugular and the subclavian veins
How does the origin of the common carotid artery vary on each side of the neck?
Left side - direct branch of the arch of the aorta
Right side - arises from the brachiocephalic artery
Describe the attachments of the digastric muscle?
Has 2 bellies divided by a small tendon that pass through a loop of connective tissue and attaches to the hyoid bone
Anterior belly - attaches to mandible
Posterior belly - attaches to mastoid process of temporal bone
What are the sensory branches of the cervical plexus?
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular
What rami make up the cervical plexus?
Anterior rami of C1 - C4
Describe the attachments of omohyoid
Superior belly - attaches to the hyoid bone. Becomes tendinous near the clavicle and passes through a small fascial sling that attaches to clavicle
Inferior belly - attaches to the scapula
What is the innervation of the infrahyoid muscles?
Ansa cervicalis
Exception is the thyrohyoid which is innervated by C1 via the hypoglossal nerve (CN XII)
What are the attachments of the platysma muscle?
From the fascia above the pectoralis major and clavicle
To lateral neck and onto the mandible
What muscle divides the anterior and posterior triangle?
Sternocleidomastoid
Where is the thyroid gland located?
Anterior aspect of the neck
Runs from the lamina of the thyroid cartilage down to the 6th tracheal ring
The isthimus lies over tracheal rings 2 or 3
What is the role of the cervical plexus?
Provides motor innervation to some of the muscles in the anterior triangle of the neck
Gives sensory innervation to the skin of neck
What is the venous drainage of the thyroid gland?
Three veins - Superior, middle and inferior on each side
Superior and middle drain into internal jugular veins
Both inferior veins drain into LEFT brachiocephalic vein
What are the 3 sets of salivary glands?
Parotid
Submandibular
Sublingual
What is the ansa cervicalis?
A nerve tissue loop that is composed of C1-C3 that supplies motor innervation to the supra and infra hyoid muscles
What is the role of the suprahyoid muscles?
To raise the hyoid bone.
Myloid and digastric also act to depress the mandible
Describe the attachments of stylohyoid
Attaches to styloid process of temporal bone and the hyoid
Describe the attachments of geniohyoid
Lies deep to mylohyoid
Attaches to inferior genial tubercle of mandible and the hyoid bone
What are the parts of the thyroid gland?
2 lobes - left and right
Connected by isthmus
Parathyroid glands are embedded on posterior surface
Where does the submandibular gland secrete saliva?
One duct on each side and open between the first and second lower incisor (either side of the frenulum)
What are the fascial layers of the neck?
Superficial fascia which lies just below the neck. Deep fascia is split into different sections depending on the area they cover.
Investing layer
Pre-tracheal layer
Pre-vertebral layer
Alar fascia and carotid sheath
What is the innervation of the supra-hyoid muscles?
Facial nerve (CN VII) - supplies stylohyoid and the posterior belly of digastric
Trigeminal (CN V3) - Mylohyoid and anterior belly of the digastric
C1 via the hypoglossal (CN XII) - geniohyoid
What are the jugular veins of the neck?
External jugular - lies anterior to the SCM in the posterior triangle
Internal jugular - lies posterior to the SCM in the anterior triangle
Anterior jugular - found in the midline of the neck and can be absent
What are the suprahyoid muscles (4)?
Digastric muscles
Mylohyoid
Geniohyoid
Stylohyoid
Where is the submandibular gland located?
Superior to the mylohyoid in in the floor of the mouth
What fascial layer covers the cervical plexus?
Pre-vertebral level of the deep fascia
What are the 3 anterior branches of the external carotid artery that supply the neck?
Superior thyroid - passes down neck to thyroid
Lingual - passes into floor of oral cavity to supply the tongue
Facial - crosses anterior surface of mandible to supply the face
What are the divisions of the anterior triangle?
Submental
Submandibular
Carotid
Muscular
What is the innervation of the platysma muscle?
Facial nerve CN VII
