Exam #6: Brachial Plexus Flashcards
From what levels is the brachial plexus derived?
Ventral rami of C5-T1
What is the preaxial side of the upper limb?
Lateral thumb side
What is the post-axial side of the upper limb?
Medial side of the arm
Draw the dermatomal distribution of the upper limb.
N/A
What is a myotome? How does the myotome distribution differ from the dermatomal distribution?
Set of muscle innervated by a specific nerve root
What does the C5 myotome control?
Elbow Flexion
Abduction (at shoulder)
What does the C6 myotome control?
Wrist extension
What does the C7 myotome control?
- Elbow extension
- Wrist flexion
- Digital extension
What does the C8 myotome control?
Digital flexion
What does the T1 myotome control?
Abduction & Adduction of the fingers
What does the biceps reflex test?
C5
What does the brachioradialis reflex test?
C6
What does the triceps reflex test?
C7
A patient presents in your office and is unable to flex his arm at the elbow or abduct his arm at the shoulder. What myotome is involved?
C5
A patient presents in your office and is unable extend his wrist? What myotome is involved?
C6
A patient presents in your office and is unable extend his arm at the elbow, flex his wrist, or extend his digits. What myotome is involved?
C7
A patient presents in your office and is unable to flex his digits. What myotome is involved?
C8
A patient presents in your office and is unable to adduct or abduct his fingers. What myotome is involved?
T1
Describe the compartments of the upper arm.
The upper arm is divided into anterior & posterior compartments.
What compartment do the anterior divisions of the brachial plexus innervate?
Anterior compartment muscles
What compartment do the posterior divisions of the brachial plexus innervate?
Posterior compartment muscles
What is the mnemonic to remember the organization of the brachial plexus?
Randy= Roots (ventral rami of C5-T1) Travis= Trunks Drinks= Divisions Cold= Cords Beer= Branches
List the trunks of the brachial plexus.
Upper
Middle
Lower
List the division of the brachial plexus.
Anterior
Posterior
List the cords of the brachial plexus.
Lateral
Medial
Posterior
What is the landmark around which the cords of the brachial plexus are described?
Axillary a.
What are the five terminal branches of the brachial plexus?
Musculocutaneous Axillary Radial Median Ulnar