Lecture 13 Clinical correlates

Question 1

What can brachial plexus injuries effect?

Answer 1

-motor function
-cutaneous sensation
(within upper limb)

Question 2

Why do you get an upper brachial plexus injury?

Answer 2

Excessive increase in angle between neck and shoulder

• occurs in trauma
• during birth of baby if shoulders become impacted by the pelvis (SHOULDER DYSTOCIA) and excessive traction to baby’s neck

Question 3

What nerve roots are affected in upper brachial plexus injury?

Answer 3

C5 & C6
Causing sensory alteration in these dermatomes and paralysis of muscles predominantly supplied by these nerve roots
C5: shoulder abduction, external rotation
C6: elbow flexion, wrist extension, supination

Question 4

What are the paralysed muscles in an upper brachial plexus injury?

Answer 4

Deltoid (axillary nerve: C5-6)
Teres minor (axillary nerve: C5-6)
Biceps brachii (musculocutaneous nerve: C5-7)
Brachiordialis (radial nerve: C5-T1)
Brachialis (musculocutaneous nerve: C5-7)
Coracobrachialis (musculocutaneous nerve: C5-7)

Question 5

What is a clinical sign of an upper brachial plexus injury?

Answer 5

Limb hangs down by the side in a internal rotation with an adducted arm and extended elbow
WAITER’S TIP POSITION
ERB’S PALSY

Question 6

Why do injuries to the lower brachial plexus occur?

Answer 6

Due to forced hyperextension/hyperabduction
-falling from a tree and grabbing onto a branch
-baby’s arm delivered first so traction is applied to arm
KLUMPKE’S SYNDROME

Question 7

What nerve roots are effected in lower brachial plexus injury?

Answer 7

C8 & T1
C8: finger flexion, finger extension
T1: finger adduction, finger abduction

Question 8

What is a clinical sign ofa lower brachial plexus injury?

Answer 8

Ulnar claw

• hyperextension of metacarpal joints, flexion of interphalangeal joints, abduction of thumb, wasting of interossei (muscle)
• paralysis effects intrinsic muscles of hand, and muscles supplied by C8 and T1 fibres