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Brachial plexus
Brachial plexus
Brachial plexus is a network of nerves that sends signals between the spinal cord and the upper extremity
It provides nerve supply to muscles, allowing the upper extremity to move
It transmits sensory information such as touch, temperature, and pain to the spinal cord and then up to the brain
Is divided up into sections called roots, trunks, divisions, cords, and branches
The spinal nerve roots involved are from C5-T1
Nerve distribution of the palmar hand
Nerve distribution of the palmar hand
These nerves originate from the brachial plexus
Median nerve provides sensory innervation to the palm side of the thumb, index finger, middle finger, and radial half of the ring finger, and the palm near these fingers
Ulnar nerve supplies sensory innervation to the little finger and the ulnar side of half of the ring finger and the palm near these fingers
Radial nerve supplies sensory innervation primarily to the dorsal surface of the hand and is not very visible when looking at a palmar view
Nerve distribution of the dorsal hand
Nerve distribution of the dorsal hand
Radial nerve supplies sensory innervation to a large portion of the radial half of the dorsal surface of the hand (with exceptions of the top parts of the fingers)
Median nerve supplies sensory innervation to the dorsal surface of the top of the thumb, index finger, middle finger, and radial half of the ring finger
Ulnar nerve supplies sensory innervation to a large portion of the ulnar half of the dorsal surface of the hand, along with the ulnar half of the ring finger and the entirety of the pinky finger
Quiz Questions
1. Which of the following correctly lists the order of brachial plexus components from spinal cord to terminal nerves?
a. Roots, cords, trunks, divisions, branches
b. Trunks, roots, cords, branches, divisions
c. Roots, trunks, divisions, cords, branches
d. Branches, divisions, cords, trunks, roots
2. Which nerve supplies sensory input to the little finger and adjacent half of the ring finger?
a. Radial nerve
b. Axillary nerve
c. Median nerve
d. Ulnar nerve
3. Which nerve's innervation is least visible when viewing the palm of the hand?
a. Ulnar nerve
b. Median nerve
c. Radial nerve
d. Musculocutaneous nerve
4. Which spinal nerve roots contribute to the formation of the brachial plexus?
a. C5–T1
b. C1–C5
c. T2–T6
d. L1–L5
5. If a patient reports numbness in the palm and palmar side of the index and middle finger, which nerve is most likely involved?
a. Ulnar nerve
b. Median nerve
c. Radial nerve
d. Axillary nerve
Quiz Answers
C
D
C
A
B
References
Images from: Atlas of Anatomy 4th Edition, Gilroy et al., 2020, Thieme Medical Publishers
Information based on lecture content from professor Dr. Earl Mayhew, DPT, BIO 634 - Human Anatomy course, University of Michigan-Flint, Fall 2022
Page updated
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