Posterior Triangle Flashcards
Investing layer (superficial) fascia
A sleeve binding all the structures in the neck; attached to ligamentum nuchae and spinous process of C7 vertebrae; splits to enclose the trapezius and sternocleidomastoid
Infrahyoid fascia
Covering the supra and infrahyoid muscles; helps reposition the hypopharyngeal complex (larynx, hyoid bone, jaw)
Pretracheal fascia
Viscera surrounded with a layer of fascia including the thyroid and parathyroid glands, trachea, and esophagus
Carotid sheath
Carotid artery, internal jugular vein, and vagus nerve
Prevertebral fascia
Deep cervical fascia covering vertebral musculature
Why are the fascial layers of the neck so important?
The fascia serves to hold things together. It also allows the muscles to slide against and around one another and isolate them, allowing them to move without interference
What is the posterior triangle made up of?
The sternocleidomastoid, the trapezius, and the clavicle
What are the sub-triangles of the posterior triangle?
The occipital triangle and the omoclavicular triangle
Action of the sternocleidomastoid
Unilaterally acts to tilt the head to the same side and rotate the head to the opposite side. Bilaterally acts to extend the head and aid in respiration when the head is fixed.
What is Erb’s point?
An area halfway along the posterior border of the sternocleidomastoid muscle that the cutaneous branches of the cervical plexus emerge; the accessory nerve is also just deep to the investing fascia at this point.
What are the cutaneous branches of the cervical plexus?
The transverse cervical nerve, the great auricular nerve, the lesser occipital nerve, and the supraclavicular nerve
Transverse cervical nerve
From ventral rami of C2-3; cutaneous nerve to throat
Great auricular nerve
From ventral rami of C2-3; cutaneous to area around ear
Lesser occipital nerve
From ventral rami of C2 (and sometimes C3); cutaneous to skin near the mastoid process
Supraclavicular nerve
From ventral rami of C3-4; splits into three branches - anterior, middle, and posterior; cutaneous to area over clavicle
Accessory nerve
Cranial nerve XI; from medulla oblongata; motor to sternocleidomastoid and trapezius
Phrenic nerve
Part of the motor portion of the cervical plexus; C3-C4-C5 roots; innervates the diaphragm; sits on top of the anterior scalene muscle
Ansa Cervicalis
Part of the motor portion of the cervical plexus; C1-C2-C3 with two limbs (roots) - C1 ventral ramus and the C2 and C3 rami
C1 ventral ramus of the ansa cervicalis
Provides separate motor innervation to the thyroid and geniohyoid muscles and also forms the Superior Root of the Ansa Cervicalis
C2 and C3 ventral rami of the ansa cervicalis
Combine to form the Interior Root of the Ansa Cervicalis; innervates the sternohyoid, sternothyroid, and omohyoid
Ventral rami of the cervical plexus
Motor portion of the cervical plexus; directly to rectus capitis lateralis, rectus capitis anterior, longus capitis, longus colli, levator scapulae, and scalene muscles
Where will the phrenic nerve lay right on top of?
Anterior scalene muscle
What does the supraclavicular triangle contain?
The lower portion of the brachial plexus, the subclavian artery and vein, the branches of the subclavian artery, and the termination of the external jugular vein
What are the subclavian artery branches?
VITamin C and sometimes D
Vertebral artery, Internal Thoracic artery, Thyrocervical trunk, Costocervical trunk, and Dorsal Scapular artery
What are the branches of the Thyrocervical trunk?
ITSA
Inferior thyroid, Transverse Cervical, Suprascapular, and Ascending Cervical
What are the branches of the Costocervical trunk?
SD
Supreme Intercostal, Deep cervical
Where does the subclavian vein run?
Behind the clavicle and in front of the anterior scalene muscle
Where does the subclavian artery run?
Between the anterior and middle scalene muscles
Where does the brachial plexus run?
Between the anterior and middle scalene muscles
Where does the phrenic nerve run?
In front of (on top of) the anterior scalene muscke
Where does the transverse cervical artery run?
In front of the anterior scalene muscle
Where does the suprascapular artery run?
In front of the anterior scalene muscle
Where does the dorsal scapular artery run?
Behind (deep to) the anterior scalene
