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UKCD Posterior Trian
learning objectives to posterior triangle
Question | Answer |
---|---|
What is the key muscle of the neck? What is it’s innervation? | The sternocleidomastoid muscle. CN XI (the spinal accessory n.) |
What does the sternocleidomastoid muscle divide the neck into? | Two triangles - an anterior and a posterior triangle. |
List the boundaries of the posterior triangle. | The trapezius posteriorly, the sternocleidomastoid anteriorly, and the clavicle inferiorly. |
What structure divides the posterior triangle into two subtriangles? | The inferior belly of the omohyoid. |
Name these two smaller triangles that the posterior triangle is split into. | A large, superior occipital triangle, and a lower, smaller supraclavicular triangle. |
List at least one important structure in the lower of these two triangles of the posterior triangle | The subclavian artery is found in the lower part of the supraclavicular triangle. |
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? | Cervical plexus = C1-C4; the brachial plexus = C5-T1. |
Which of these two plexuses is purely sensory? | The cervical plexus. |
Be able to label the muscles that form the floor of the posterior triangle, from inferior to superior. | The muscles of the floor (from inferior to superior) are: scalenus anterior, scalenus medius, levator scapulae, splenius capitis, semispinalis capitis. |
Between which two muscles is the brachial plexus located? | The scalenus anterior and medius. |
Where is the scalenus posterior located? | It lies posterior to the scalenus medius. |
Name the nerve that can be found lying superficial to the scalenus anterior? | The phrenic nerve. |
Name the nerve superficial to the levator scapulae? | CN XI - the (spinal) accessory nerve. |