Chapter 4: Upper Limb Flashcards
The brachial plexus is formed by what nerves in the CNS?
ventral rami of C5 through T1 spinal nerves
What are the 5 major nerves that arise from the brachial plexus?
musculocutaneous
median,
ulnar,
axillary,
radial
The axillary and radial nerves contain the posterior or anterior division fibers?
posterior division fibers
The musculocutaneous, median, and ulnar nerves contain the posterior or anterior division fibers?
anterior division fibers
Are the palmer compartments that function mainly as flexors of the upper limb inervated by anterior or posterior division fibers?
anterior
Be able to draw a diagram of the brachial plexus
Refer to image.
The musculocuatenous nerves are derived from what nerve roots?
C5
C6
C7
In general, what are the muscles innervated by the musculocutaneous nerves?
all the muscles of the anterior compartment of the arm
What are the primary actions of the muscles of the anterior portion of the arm?
flex elbow
supination (biceps brachii)
The median nerve is carried by what nerve roots?
C5-T1
What muscles does the median nerve innervate?
A. Forearm
anterior compartment except 1.5 muscle by ulnar nerve (flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus.
B. Hand
Thenar compartment
Central compartment
Lumbricals: Digits 2 and 3
First 3 1/2 digits dorsal 3 1/2 finger tips
What are the primary actions of the median nerve? In the forearm and the hand?
Forearm
- flex wrist and all digits
- pronation
Hand
- Opposition of thumb
- flex metacarpophalangeal (MP) and extend interphalangeal (PIP and DIP ) joints of digits 2 and 3
What are the roots that contribute to the ulnar nerve?
C8- T1
What muscles do the ulnar nerves innervate?
A. Forearm
Anterior Compartment: 1 (1/2)
muscles not innervated by the median nerve
B. Hand
- hypothenar compartment
- central compartment
-interossei muscles: palmer and dorsal - lumbricals: digits 4 & 5
- adductor pollicis
Primary action of ulnar nerve on the hand?
Dorsal - Abduct digits 2-5 (DAB)
Palmer - Adduct digits 2-5 (PAD)
Assist lumbricals in MP flexion and IP extension digits 2-5
Flex MP and extend PIP and DIP joints of digits 4 and 5
Adduct the thumb
What are the primary actions of the ulnar nerves on the muscles in the forearm?
flex wrist (weak) and digits 4 and 5
What are the nerve roots that form the axillary nerve?
C5-C6
What muscles are innervated by the axillary nerve?
deltoid
teres minor
What are the primary actions of the axillary nerve?
abduct shoulder 15 -110
Lateral rotation of shoulder
What are the nerve roots that the radial nerve is derived from?
C5-T1
What muscles are innervated by the radial nerve?
posterior compartment muscles of the arm and forearm.
What are the primary actions of the posterior compartment muscles of the arm and forearm?
extend MP, wrist, and elbow
supination (supinator muscle)
What muscles does the dorsal scapular nerve innervate?
rhomboids
What muscle/s does the long thoracic nerve innervate? What is the function of this muscle?
serratus anterior -protracts and rotates scapula superiorly
What muscles does the suprascapular nerve innervate?
Supraspinatus- abduct shoulder 1-15
Infraspinatus - laterally rotate shoulder
What nerve roots make up the suprascapular nerve?
C5-6
What muscle is innervated by the lateral pectoral nerve?
pectoralis major
What muscle is innervated by the medial pectoral nerve?
pectoralis major and minor
What muscle is innervated by the upper subscapular nerve?
subscapularis
What muscle is innervated by the middle subscapular (thoracodorsal) nerve?
latissimus dorsi
What muscle is innervated by the lower subscapular nerve
subscapularis and teres major
What muscle is innervated by the medial brachial cutaneous nerve?
skin of medial arm
What part of the body is innervated by the medial antebrachial cutaneous nerve?
skin of medial forearm
Why is palm sensation not affected by carpal tunnel syndrome?
the superficial palmar cutaneous branch of the median nerve passes superficial to the carpal tunnel
The skin of the palm of the hand is supplied by what nerves?
median and ulnar
How much of the hand does the median nerve innervate
lateral 3 1/2 digits and the adjacent area of the lateral palm and thenar surface and tips of 3 1/2 digits on dorsal surface
The ulnar nerve supplies what parts of the hand?
medial 1 1/2 digits and the hypothenar eminence
What parts of the hand does the radial nerve supply?
skin of the dorsum of the hand in the area of the first dorsal web space, including the skin over the snuffbox
dorsum of first 3 1/2 fingers outside of the fingertips
What is another name for Erb-Duchenne Palsy?
Waiter’s Tip Syndrome
Where is the lesion found in an individual with Erb-duchenne Palsy?
Trauma damages C5 and C6 nerve roots
What are common causes of Erb-Duchenne Palsy?
occurs when the head and shoulder are forcibly separated (e.g accident or birth injury or herniation of disk)
What nerves are primarily affected in Erb-Duchenne Palsy?
axillary, suprascapular, and musculocutaenous nerves
What muscles are affected in Waiter’s Tip?
loss of intrinsic muscles of the shoulder and muscles of the anterior arm
deltoid
infraspinatus
biceps brachii
Where is the lesion found in Klumpke’s paralysis?
C8 and T1
What is a common cause of Klumpke’s Paralysis?
usually occurs when the upper limb is forcefully abducted above the head (e.g grabbing an object when falling, thoracic outlet syndrome, birth injury)
What nerves are primarily affected in Klumpke’s Paralysis?
ulnar nerve
What muscles are primarily affected in Klumpke’s paralysis?
the intrinsic muscle of the hand
Major sign of Klumpke’s palsy?
sign is combo of “claw hand” and “ape hand”
sensory loss on medial forearm and medial 1 1/2 digits
Is it possible for a person with Klumpke’s Paralysis to show signs of Horner syndrome?
yes
Which dermatome is affected when there is a lesion at C5?
lateral border of the upper arm
Which dermatome is affected when there is a lesioned root at C6?
lateral forearm to thumb
What is the dermatome affected when there is a lesion at C8?
medial forearm to little finger
What is the dermatome affected when there is a lesion at T1?
medial arm to elbow
What are muscles affected when there are C5 lesions?
deltoid
rotator cuff
serratus anterior
biceps
brachioradialis
What are muscles affected when C6 is lesioned?
biceps
brachioradiallis
brachialis
supinator
Reflex test for C6?
biceps tendon
What are the muscles affected if C8 nerve root is lesioned?
- finger flexors
- wrist flexors
- Hand muscles
What are some muscles affected if the T1 nerve root is damaged?
Hand muscles
Is elbow extension spared in lesions of the radial nerve distal to the axilla?
yes
Laceration of the radial nerve at the wrist symptoms?
- no motor loss
- sensory loss only on dorsal aspect of thumb (first dorsal web space)