Nerves - The Upper Limb Edition

Welcome to part 2 in our series on nerves! This one is alllll about the upper body.

Before we jump in, make sure your background knowledge is up to date by reviewing our Nerve 101 blog from earlier this year.


Okay, straight to it people!


Why do I care about my upper body nerves in the first place??


If the nerves in your upper body aren’t having a good time, you may notice symptoms like:

  • Strange sensations- pins and needles, numbness or tingling. This is especially common in the hands. It might happen in extreme ranges of motion, or if we hold a stretch or move for a long time.

  • Restricted movement that doesn’t seem to improve when you stretch. This might be overhead, out to the side (reaching back for superman), or behind the back, for example.

  • Loss of strength, such as grip. Usually this is one or two muscle groups only and just won’t seem quite right. It might come on suddenly and be position dependent- different from just fatiguing during training.

When the nerves in the upper body are functioning well, they:

  • Allow us full range of motion, to be able to stretch our muscles and move further.

  • Tell us information about where our arms are, how our muscle engagement is and how our grip on the pole feels.

  • Tell our muscles when to work, in what order and how strongly.

  • Act as our danger signal, sending pain messages when something doesn’t seem right.

Let’s have a look at our amazing nerves in detail.


Upper body nerves


In our blog Nerve 101, we talked about how our nerves start off in the brain and spinal cord (Central Nervous System, CNS). Beyond the brain and spinal cord, the rest of the nerves are part of the PNS (Peripheral Nervous System). In today’s blog we are looking at the PNS of the neck, arms and torso, and these come from the spinal nerve root exits C1-T12. This is all 8 of the cervical nerve roots (nerves exiting the spine in the neck) and the 12 thoracic nerve roots (upper back).


Here is a little review of where they are and what they do:


Peripheral nerve bundles

Once our nerves travel further away from the spine, they weave together to join other nerves, then divide off again in different patterns, a bit like a 3D macrame wall hanging! Between the spine and upper arm, this organised mess of nerves is called the Brachial Plexus. It contains all the nerves that travel down the arm.


Past the shoulder, the Brachial Plexus divides off into smaller bundles of nerves. There are names for many different bundles, but here are the 3 most commonly talked about are the radial, median & ulnar nerves.


Nerve Function and Pole Dance


As we talked about in Nerve 101, nerves don’t stretch. Like the cord on a vacuum cleaner, they can become caught on structures they are passing by, limiting their ability to slide and glide through our body.


If they get a little bit stuck, we can find our mobility limited. If they become compressed, we start to get more unpleasant symptoms like weakness, altered sensation, and numbness.


How can we test if a nerve is lacking mobility?


It can be tricky to do yourself, but here are some simple self-tests try. Let’s look at each individual nerve.


In each of the following tests, we lengthen out one of the major peripheral nerves. Once we feel some pulling, restriction in movement or other sensation, we stop. We then use head movements to increase and reduce tension on the nerve to check if that is the cause of the symptoms. If neck movement changes the symptoms in the limb, we have a positive test. This is known as sensitising. A positive test means that nerve mobility is probably affected.


  1. Radial Nerve

The radial nerve innervates (goes to and from) the thumb, plus the back of the hand on the same side. If your radial nerve (or its nerve roots) lacks mobility, you may have trouble with moves where the arm is behind your back, like:

- Reverse baseball grip

- Reverse elbow moves such as satellite

- Side line

- Planche variations


Test:


a. Arm movement: Cross the thumb across your palm and curl the fingers into a fist around it. Flex the wrist, keeping the fingers in tight. Straighten the elbow, turn the arm in and then extend the arm out behind you. Stop at the first point that you feel pulling or changes in sensation and move on to step 2.



This is a quick variation of what would be done in the physiotherapy clinic. For those of you who love to know all the specific details, the main anatomical movements that bias the radial nerve are:

  • Thumb, index finger and wrist flexion

  • Forearm pronation and elbow extension

  • Shoulder internal rotation and extension

  • Scapular depression


b. Tilt the head away from the arm you are testing. Does this increase the symptoms? This may be a positive test.


c. Tilt the head toward the side you are testing. Does this reduce the symptoms or allow you to move your arm further in to the test? This confirms you have a positive test, i.e. that your radial nerve mobility is reduced.


2. Median Nerve

The median nerve supplies most of the palm, plus the front of the index and middle fingers and thumb. If this nerve or its roots are struggling, you might have trouble with:

  • Reaching out behind you for moves like superman, broken doll, or closed allegra

  • Your hand going numb when your wrist is either very flexed or extended, eg in a plank or handstand.

  • Grip strength, especially reaching behind you or with arm overhead

  • Bridges


Test:

*Again, if you get any symptoms or restriction, stop and move to the neck part of the test

a. Arm movement: start with the arm directly to the side of you with the elbow bent (wrist near the shoulder). Extend the wrist and the fingers, palm facing up (like carrying a platter of food). Slowly extend the elbow, straightening the arm out to the side toward horizontal.


For those who want to know the anatomical motions that bias the median nerve:

  • Scapular depression

  • Shoulder horizontal abduction and external rotation

  • Forearm supination

  • Wrist and finger extension.

b. Add in a head tilt away from the arm you’re testing. Does this increase your symptoms?


c. Add a head tilt toward the arm you’re testing. Does this relieve the symptoms or allow you more range of motion? This is a positive test.


3. Ulnar Nerve


The ulnar nerve innervates the little finger, part of the 4th finger and the same side of the hand. Pole moves involve combinations of internal shoulder rotation and overhead motion might cause difficulty if your ulnar nerve isn’t moving well:

  • Twisted grip moves overhead:

  • TG shoulder mount

  • TG split grip spins, such as air walks

  • Ballerina

  • Vortex

  • Bird of paradise

  • Batman, vomitron and other overhead bracket type grips

Test: *Again, if you get any symptoms or restriction, stop and move to the neck part of the test.


a. Arm movement. Stop as soon as you feel any pulling or changes in sensation and move to step 2.

Make an “ok” sign and turn it upside down by turning the fingers back toward you. Keep the elbow directly out to the side from you and don’t let the shoulder blade lift. Try to take the hand and place it on your face like one half of a pair of glasses.