Posterior Triangle of Back Flashcards
List the boundaries of the posterior triangle (posterior, anterior, inferior/base, floor, roof)
Posterior: trapezius
Anterior: sternocleidomastoid
Inferior: clavicle
Floor: musculature and prevertebral fascia
Roof: investing layer of deep cervical fascia
What is the key muscle of the neck? What is it’s innervation? What does this muscle divide the neck into?
The sternocleidomastoid muscle, innervated by CNXI, divides neck into two triangles (anterior and posterior)
What structure divides the posterior triangle into two subtriangles? Name them
The inferior belly of the omohyoid muscle divides it into the large superior occipital triangle and the lower supraclavicular triangle.
List at least one important structure in the lower of these two triangles (occipital & supraclavicular)
The subclavian artery
The ventral rami of which two plexuses can be found in the posterior triangle?
The brachial and cervical plexuses.
What are the root values (spinal cord levels involved in the formation) of each plexus? What do they supply?
Cervical plexus- C1-C4, sensory innervation to neck & upper thorax
Brachial plexus- C5-T1, motor & sensory to upper limb
Which is purely sensory– cervical or brachial plexus?
Cervical
What are the root values (spinal cord levels involved in the formation) of each plexus?
inferior to superior- scalenus anterior, scalenus medius, levator scapulae, splenius capitis, semispinalis capitis.
Between which two muscles is the brachial plexus located?
Scalenus anterior and scalenus medius.
Where is the scalenus posterior located?
posterior to the scalenus medius
Name the nerve that can be found lying superficial to the scalenus anterior?
Phrenic
Name the nerve superficial to the levator scapulae?
CN XI
Posterior compartment contains what and and required for what?
contains vertebral column and musculature required for flexion/extension of the neck. It is specialized for support
Anterior compartment of neck
Divided into 2 anterior triangles. It includes the larynx/trachea and pharynx. Contains a neurovascular bundle
Superior and inferior attachments of SCM?
Superior- mastoid process
Inferior- sternum & clavicle
Function of sternocleidomastoid muscle?
unilaterally tilt head toward the shoulder of the same side, rotating the face to the opposite side. bilaterally protract the head
What are the boundaries of the neck?
Superior- superior nuchal line, mastoid process, inferior border of mandible
Inferior- clavicle & sternum
Posterior- trapezius
Anterior- midline
What are the four layers of deep cervical fascia of the neck?
- Investing layer (roof of post/ant triangles)
- Pretracheal layer (sheath around thyroid)
- Prevertebral layer (surrounds vertebra & musculature)
- Carotid sheath (all 3 layers, encloses neruovascular bundle of neck)
Which cervical fascia layer is the fascial carpet?
The prevertebral layer
What muscle divides the posterior triangle in two? What are the names of these two things?
The inferior belly of the omohyoid muscle divides the posterior triangle into the larger superior occipital triangle and the lower smaller supraclavicular triangle.
What are the four nerves of the cervical plexus?
Lesser occipital, transverse cutaneous, great auricular, supraclavicular
What are the muscles of the posterior triangle floor?
1) semispinalis capitis
2) splenius capitis
3) levator scapulae
4) scalenus medius
5) scalenus anterior
