9.23.16 Posterior Triangle Flashcards
What are the fascial layers of the neck?
- Investing (superficial) layer of dense connective tissue
- Infrahyoid fascia
- Pretracheal fascia
- Carotid sheath
- Prevertebral (deep cervical) fascia
What is the sleeve that binds all structures to the neck?
Investing layer of dense connective tissue
What is the investing fascia of the neck attached to?
Ligamentum nuchae and spinous process of C7 vertebrae
What covers the supra and infra-hyoid muscles (strap muscles)?
Infrahyoid fascia
What is the viscera surrounded with a layer of fascia including the thyroid and parathyroid glands, larynx, trachea, and esophagus?
Pretracheal fascia
What covers the carotid artery, internal jugular vein, and vagus nerve?
Carotid sheath
What covers the vertebral musculature?
Prevertebral (deep cervical) fascia
What are the boundaries of the posterior triangle (anterior, posterior, inferior)?
Anterior: sternocleidomastoid muscle
Posterior: trapezius
Inferior (base): Clavicle
What is the origin and insertion of sternocleidomastoid?
Sternal head origin: anterior surface of manubrium
Clavicular head origin: upper surface of medial 1/3 of clavicle
Insertion: lateral usrface of matoid process; lateral half of superior nuchal line of occipital bone
What innervates sternocleidomastoid?
Accessory nerve (CN XI)
What is the function of sternocleidomastoid?
Bilaterally - flex head, raise thorax
Unilaterally - turns face toward opposite side
What supplies sternocleidomastoid?
Sternocleidomastoid branch of superior thyroid and occipital arteries, muscular branch of suprascapular artery, occipital branch of posterior auricular artery
What are the three scalene muscles?
Anterior scalene, middle scalene, posterior scalene
What is the origin and insertion of anterior scalene?
Origin: anterior tubercles of transverse processes of C3-C6
Insertion: Scalene tubercle on 1st rib
What is the origin and insertion of middle scalene?
Origin: posterior tubercles of transverse processes of C2-C7
Insertion: Upper surface of 1st rib (behind subclavian groove)
What is the origin and insertion of posterior scalene?
Origin: posterior tubercles of transverse processes of C4-C6
Insertion: Outer surface of 2nd rib (behind attachment of serratus anterior)
What innervates anterior scalene?
Anterior rami of cervical nerves (C5-C8)
What innervates middle scalene?
Anterior rami of cervical nerves (C3-C7)
What innervates posterior scalene?
Anterior rami of lower four cervical nerves
What is the function of anterior scalene?
Elevates 1st rib, bends neck
What is the function of middle scalene?
Elevates 1st rib, bends neck
What is the function of posterior scalene?
Elevates 2nd rib, bends neck
What is the largest and longest of the 3 scalenes?
Middle scalene
What makes up the occipital triangle?
Cervical plexus (cutaneous branches and motor branches), CN XI (accessory), phrenic nerve, and transverse cervical artery
___ divides the posterior triangle of the neck into two smaller triangles.
The inferior belly of the omohyoid muscle
Where is the occipital triangle found?
Above the omohyoid muscle
Where is the omoclavicular triangle found?
Below the omohyoid muscle
What are the two subtriangles of the posterior triangle?
Occipital triangle and omoclavicular triangle
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 from; the accessory nerve is also just deep to the investing fascia at this point.
What are the cutaneous branches of the cervical plexus?
- Transverse cervical nerve
- Great auricular nerve
- Lesser occipital nerve
- Supraclavicular nerve
The transverse cervical nerve branches from the ventral rami of ___ and is the cutaneous nerve to the ___.
C2-C3; throat
The greater auricular nerve branches from the ventral rami of ___ and is the cutaneous nerve to the area around the ___.
C2-C3; ear