Posterior Triangle of the Neck Flashcards
What is the anterior border of the posterior triangle?
Posterior border of the SCM
What is the posterior border of the posterior triangle?
Anterior border of trapezius
What is the base of the posterior triangle?
Clavicle
What are the contents of the posterior triangle?
- External jugular vein
- Roots of brachial plexus
- Accessory nerve
- Cervical and supra-clavicular lymph nodes
What nerves are present in the posterior triangle?
- Lesser occipital (C2)
- Great auricular (C2,3)
- Lateral supraclavicular (C3,4)
- Medial supraclavicular (C3,4)
What cutaneous nerves are present in the posterior triangle?
- Greater occipital
- Lesser occipital
- Post. rami of C3-5
What veins are present in the posterior triangle of the neck?
External jugular anterior to SCM
What deep structures are present in the posterior triangle?
- Transverse cervical artery
- Internal jugular vein
- Suprascapular
What does the phrenic nerve pass over?
Crosses obliquely over anterior surface of anterior scalene
What do the roots of the brachial plexus pass through?
Between middle and anterior scalene
What is the innervation of the SCM?
- Motor innervation = spinal accessory nerve (CN XI)
- Proprioception = cervical plexus C2,3
What movements are permitted by the SCM?
- Lateral flexion with rotation
- Extension at atlanto-occipital joints
- Flexion of cervical vertebrae (person is supine)
What is this muscle? picture
Trapezius
A = Ascending part
B = Transverse part
C = Descending part
What is the action of the ascending part of the trapezius?
Depress the scapula
What is the action of the transverse part of the trapezius?
Retracts the scapula
What is the action of the descending part of the trapezius?
- Elevate scapula
- Rotate glenoid cavity
What innervates the trapezius?
- Spinal accessory nerve (CN XI)
- Cervical plexus C3,4 (proprioception)
What muscles form the floor of the posterior triangle?
- Omohyoid
- Splenius capitis
What is this muscle? picture
Omohyoid
What is the function of the omohyoid?
Depress the hyoid bone
What innervates the omohyoid?
Ansa cervicalis
What is this muscle? picture
Splenius capitis
What is the function of the splenius capitis?
Extend and rotate the neck
What innervates the splenius capitis?
Dorsal rami middle cervical
What is this muscle?
Levator scapulae
What is the origin of the levator scapulae?
- Transverse processes of atlas and axis
- 3rd and 4th C vertebrae
What is the insertion of the levator scapulae?
- Medial scapular border between superior angle between medial end of scapular spine
What is the function of the levator scapulae?
- Control scapular position
- Elevate shoulder with trapezius
- Shoulder fixed
- Lateral flexion of neck to the same side
What innervates the levator scapulae?
Direct C3,4,5 via dorsal scapular nerve
What are these muscles? picture
picture
What innervates the scalenes?
Anterior scalene = ant. rami C4-7
Middle scalene = ant. rami C3-7
Posterior scalene = ant. rami C5-7
What is the function of the scalenes?
- Flex neck (bilateral)
- Tilt head to same side (unilateral)
- Elevate upper ribs
