Lecture 18: Dermatomes, Myotomes, Plexuses Flashcards
Where are the nerves completely “differentiated” from one another?
In the anterior and posterior rootlets and roots
(Posterior is only sensory, anterior is only motor - there is no mixing)
What is the definition of a dermatome?
The area of skin innervated by afferent nerve fibers by a single posterior spinal root.
Where is the Epaxial Region in terms of Dermatomes?
The region of the spine and directly adjacent muscles
What dermatome corresponds to the top of the shoulder?
C4
What area makes up the C5 dermatome?
The area below the deltoid.
On the posterior side, the Deltoid is C4 and C5, mostly C4 on the anterior side
What dermatome corresponds to most of the lateral antebrachial region of the arm, including the first and lateral second digit?
C6
What dermatome corresponds to the middle finger?
C7
What dermatome corresponds to the little finger?
C8
What area of skin is the T1 dermatome?
The medial antebrachium
What dermatomes are associated with “Sciatica?”
The sacral dermatomes
(S1-S5)
What is shown in a “Nerve Map?”
The regions of skin innervated by a single cutaneous nerve
What is the definition of a Myotome?
The muscles innervated by a single efferent anterior root.
Note: Most muscles are composed of more than one myotome
What dermatome crosses the bellybutton?
T10
What dermatome crosses the nipple line?
T4
Which spinal nerves contribute to:
Musculocutaneous N.
C5-C7
