Posterior Cervical Triangle Flashcards
What are the borders of the posterior cervical triangle?
- Sternocleidomastoid muscle
- Trapezius muscle
- Clavicle
Posterior triangle is divided by…
inferior belly of omohyoid
The inferior belly of omohyoid divides the posterior cervical triangle into what two smaller triangles?
- Occipital triangle
- Subclavian triangle
What six muscles can be found in the posterior triangle?
- Splenius capitis
- Levator scapulae
- Anterior scalene (inferomedial angle of triangle or behind SCM)
- Middle scalene
- Posterior scalene
- Omohyoid (inferior belly)
Innervation of splenius capitis
Posterior rami of middle cervical spinal nerves
Actions of splenius capitis
Laterally flexes and rotates head and neck to same side; acting bilaterally, extends head and neck
Innervation of levator scapulae
Dorsal scapular nerve C5 and cervical spinal nerves C3 and C4
Actions of levator scapulae
Downward rotation of scapula and tilts its glenoid cavity inferiorly by rotating scapula
Innervation of anterior scalene
Cervical spinal nerves C4-C6
Actions of anterior scalene
Flex head
Innervation of middle scalene
Anterior rami of cervical spinal nerves
Actions of middle scalene
Flexes neck laterally; elevates 1st rib during forced inspiration
Innervation of posterior scalene
Anterior rami of cervical spinal nerve C7 and C8
Actions of posterior scalene
Flexes neck laterally; elevates 2nd rib during forced inspiration
Which arteries of the posterior triangle are branches of thyrocervical trunk?
- Transverse cervical artery
- Suprascapular artery
The transverse cervical artery is superficial to…
- anterior scalene
- phrenic nerve
- trunks of brachial plexus
The transverse cervical artery runs ___ toward ___ and bifurcates into ___
…runs posteriorly toward trapezius and bifurcates into superficial and deep branches
The suprascapular artery is ___ to the clavicle
posterior
The suprascapular artery is inferolateral across…
- anterior scalene
- phrenic nerve
- 3rd part of subclavian artery
- cords of brachial plexus
What are the arteries of the posterior triangle?
- Branches of thyrocervical trunk (transverse cervical and suprascapular arteries)
- Third part of subclavian artery
- Occipital artery
Where is the third part of the subclavian artery in relation to ribs and brachial plexus?
- Lies on first rib
- Anterior to inferior (lower) trunk of brachial plexus
What are the veins of the posterior triangle?
- External jugular vein
- Subclavian vein
The external jugular vein is deep to ___ and superficial to ___
deep to platysma and superficial to SCM
Describe drainage by the external jugular vein
Drains most of scalp and lateral face into subclavian vein
The subclavian vein is anterior to…
anterior scalene
The subclavian vein joins ___ to form the ___ posterior to the medial end of the clavicle
joins internal jugular vein to form the brachiocephalic vein posterior to the medial end of the clavicle
What are the three main motor innervation sources of the posterior triangle?
- Spinal accessory (CN XI)
- Trunks of brachial plexus
- Deep motor branches of cervical plexus
Which trunks of the brachial plexus innervate the posterior triangle?
- Superior (upper) trunk: C5-C6
- Middle trunk: C7
- Inferior (lower) trunk: C8-T1
Where in the brachial plexus will the suprascapular nerve (C4-C6) branch from?
Superior (upper) trunk
What are the deep motor branches of the cervical plexus innervating the posterior triangle?
- Dorsal scapular nerve (C4-C5)
- Long thoracic nerve (C5-C7)
- Nerve to subclavius (usually C4-C6)
- Phrenic nerve (C3-C5)
What structures are innervated by the dorsal scapular nerve?
Rhomboids; occasionally levator scapulae
What structures are innervated by the long thoracic nerve?
Serratus anterior
What structures are innervated by the suprascapular nerve?
Supraspinatous and infraspinatus muscles; glenohumeral joint
What structures are innervated by the subclavian nerve?
Subclavius and sternoclavicular joint
Sensory nerves of the posterior triangle are derived from…
cervical plexus
Which sensory nerves are in the nerve point of the neck (Erb’s point)?
- Lesser occipital nerve (C2)
- Great auricular nerve (C2-C3)
- Transverse cervical nerve (C2-C3)
- Supraclavicular nerves (C3-C4) (medial, intermediate, lateral)
