Brachial Plexus Flashcards
All of the nerves for the upper extremity arise from the:
brachial plexus
Brachial plexus
a network of nerves that practically provides full sensory and motor innervation to the arm
Where does the axillary artery originate?
continuation of the subclavian artery
What is the extent of the axillary artery?
extends from outer border of 1st rib to lower border of teres major
What does the radial nerve innervate?
all extensors!
Injury of the radial nerve in the axilla typically results in:
wrist drop
Injury of the radial nerve would result in sensory loss on:
- posterior surface of the lower part of the arm
- down a narrow strip on the back of the forearm
- lateral part of the dorsum
- dorsal surface of the roots of the lateral 3.5 fingers
Axillary nerve extends from which spinal nerves?
C5 and C6
Axillary is a terminal branch of which cord?
posterior
The axillary nerve passes through the _____ ______ in the axilla with the posterior circumflex humeral artery around the surfical neck of the humerus
quadrangular space
Motor functions of the axillary nerve
innervate deltoid muscle and teres minor
Sensory innervation of the axillary nerve
skin over the shoulder
Three ways the axillary nerve is usually injured
- fracture of surgical neck of humerus
- downward dislocation of the shoulder joint
- compression from the incorrect use of crutches
The loss of cutaneous sensation is consistent with an injury to the _____ nerve.
radial
The difficulty extending at the wrist and elbow is also consistent with a ______ nerve injury
radial
Which nerve is the largest branch of the lateral cord?
musculocutaneous nerve
Which muscles does the musculocutaneous nerve innervate?
- biceps brachii
- brachialis
- coracobrachialis
Where does the musculocutaneous nerve end on the forearm?
ends on the forearm as lateral cutaneous nerve of the forearm
An injury to the __________ nerve is relatively uncommon, as it is well protected within the axilla.
musculocutaneous
The most common cause of musculocutaneous injury
stab wound to the axilla region
Loss of motor functions of the musculocutaneous nerve
- weak flexion at the shoulder
- weak flexion at the elbow
- supination greatly affected
The axillary nerve arises directly from which part of the brachial plexus
posterior cord
Where does the median nerve derive from?
lateral and medial cords (C6-T1)
Motor supply of the median nerve
- flexor muscles in the forearm except flexor carpi ullnaris and the ulnar head of flexor digitorum profundus
- muscles of the thenar eminence and the radial two lumbricals
Sensory supply of the median nerve
skin of
- palmar and distal dorsal aspects of the lateral three-and-the-half digits and adjacent palm
- palmar and distal dorsal aspects of the thumb and radial half of 2nd digit
- palmar and distal dorsal aspects of the adjacent sides of 2nd-4th digits
- central palm
What nerve is also known as the “million-dollar nerve” to signify its importance of basic hand function
median
Conditions associated with median nerve damage
- carpal tunnel syndrome
- hand of benediction
- ape hand deformity
Where does the ulnar nerve lie?
on the medial side of axillary artery
Where does the ulnar nerve descend?
down the medial aspect of the arm, medial to biceps brachii and anterior brachialis
The ______ nerve can broadly be described as the nerve of the hand, as the nerve innervates the vast majority of the intrinsic hand muscles.
ulnar
