Lecture 4--brachial Plexus Flashcards
What is the saying for the brachial plexus
Robert Taylor Drinks Cold Beer.
What do the dorsal rami supply?
Joints of the vertebral column, deep back muscles and the skin of the back. Everything else is ventral rami.
Where are the ventral rami?
Between the anterior and middle scalene muscles. They are Supraclavicular meaning they are above the clavicle.
Where are the trunks located?
Anterior surface of the middle scalene. They are Supraclavicular meaning they are above the clavicle.
Where are the trunks located?
Posterior and inferior to the clavicle. They are infraclavicular.
How are the cords named?
In relation to the axillary artery. The medial cord is lateral and the lateral cord is medial. It is infraclavicular.
What are the components of the brachial plexus?
Rami, trunks, divisions, cords, branches
___ runs posteriorly along the medial border of the scapula with its artery. It is motor to the levator and rhomboids.
Dorsal scapular nerve c4-c5
___ descends posterior to the c8 and t1 ventral rami on the middle scalene and passes distally on the external surface of the serratus. It is motor to the serratus.
Long thoracic nerve c5-c7
What nerves come off the branches of the brachial plexus
Dorsal scapular nerve and long thoracic nerve
What nerves come off the trunks of the brachial plexus
Superior trunk: supra scapular nerve c4-c6. And nerve to subclavius c4-c6.
___ goes posteriorly in the posterior triangle of the neck, through the suprascapular notch. It is motor to the infraspinatus and supraspinatus.
Suprascapular nerve c4-c6
___ juts straight forward into the clavicle. Descends posterior to the clavicle and anterior to the brachial plexus and subclavian artery. Motor to the subclavius.
Nerve to subclavius.
What nerves come off the divisions of the brachial plexus
NONE
What nerves come off the cords of the brachial plexus
Lateral: lateral pectoral nerve, musculocutaneous nerve,
Posterior: upper subscapular nerve, thoracodorsal nerve, and lower subscapular nerve, axillary nerve, and radial nerve.
Median: medial pectoral, medial brachial cutaneous, medial antebrahisl cutaneous, median, and ulnar
___ pierces the clavipectoral fascia to reach the deep surface of the pec major. It’s motor to the pec major. Goes into the deep surface of the pec major.
Lateral pectoral nerve
____ diverges laterally, leaving the axilla by piercing the corachobrachialis.
Musculocutaneous nerve
____ is motor to the anterior compartment of the arm and sensory to the lateral aspect of the arm (lateral antebrahisl cutaneous).
Musculocutaneous nerve
____ passes posteriorly and enters the subscapularis. It is motor to the subscapularis
Upper subscapular nerve
____ runs inferolaterally along the posterior axillary wall.
Thoracodorsal nerve
____ passes inferolaterally deep to the subscapular artery and vein.
Lower subscapular nerve
Motor to the subscapularis and teres major
Lower subscapular nerve
Turns posterolaterally to pass the posterior aspect of the arm through the quadrangular space with the posterior circumflex humeral artery.
Axillary nerve
Descends posteriorly to the axillary artery. Winds around the humerus with the profunda brachii.
Radial nerve
Motor to the posterior compartment of the forearm and arm.
Radial nerve
Sensory to the posterior and inferolateral aspects of the arm, posterior aspect of the forearm and dorsum of the hand lateral to a line bisecting the 4th digit from the dip and pip joints proximal
Radial nerve
Passes between the axillary artery and vein and pierces the pec minor.
Medial pectoral nerve
Runs along the medial side of the axillary vein. Joins often, with the intercostobrachial nerve on its way to the arm.
Medial brachial cutaneous nerve
Sensory to the medial aspect of the arm
Medial brachial cutaneous nerve
Runs between the axillary artery and vein
Medial antebrahial cutaneous nerve
Sensory to the medial aspect of the forearm
Medial antebrahial cutaneous nerve
Runs anterior, or lateral to, the axillary artery.
Median nerve
Motor flexors of the forearm, promotors of the forearm, and thenar muscles.
Median nerve
Runs between the axillary artery and vein.
Ulnar artery
Motor to fcu, ulnar half of fdp, intrinsic muscles of the hand except the ones Innervates by the median nerve.
Ulnar nerve
What would an upper brachial plexus injury look like in the clinic? (C5-c6)
Trouble with flexing the elbow. C5 is elbow flexion and musculocutaneous nerve supplies this. If just c5 you wouldn’t have complete loss but you would have difficulty with elbow flexion. Shoulder abduction would be difficult because the deltoid and the supraspinatus are supplied by the axillary and suprascapular nerves. Scapular retraction would be harder, c4-c5, with dorsal scapular nerve but you will still have the spinal accessory nerve, so this may not be as obvious. Shoulder medial rotation, but a much bigger loss of lateral rotation because of all the rotator cuff muscles. This can be called Erb’s palsy or Erb’s dusheine palsy. They show position of addiction, medially rotated, and extended.
How would a lower brachial plexus injury present?
This is c8-t1. Usually a hyperabduction injury. Less common, but like falling and catching a tree. C8 is finger flexion and t1 is finger abduction. What you see when you have klumpie’s palsy is something called claw hand and this will result in an imbalance of flexors and extensors and a loss of intrinsic muscles of the hand.
Wrist drop usually indicates what?
Radial nerve injury
