The Radial Nerve branches from the Brachial Plexus above the Clavicle collar bone and emerges at the top rear of the upper arm near the armpit. It then wraps downwards diagonally around the upper arm close to the surface, before sinking deeper near the lower end of the Biceps muscles, and then through the elbow region, supplying muscles that straighten the elbow, and lift and straighten the wrist, thumb, and fingers. The radial nerve transmits feeling from the skin on the outside of the thumb and on the back of the hand and the index finger, middle finger, and half of the ring finger and is positional, to a certain degree, by the tightening and loosening of muscles in the back, shoulder, arm and hand, and by the angle and rotation of joints. It may be in slightly different positions and asymmetric in different subjects.

Compression of the Radial Nerve will be felt as numbness in the back of the hand and/or lower parts of the thumb, index and middle fingers. Most Radial Nerve problems are generated by improper alignment and rotation of joints, a poorly positioned or over-tight upper chest wraps, or lower chest wrap, and/or the latches retaining them.

The Ulnar Nerve also runs down the inside of the arm to the wrist very closely bundled to the Median Nerve, and supplies muscles that help bend the wrist and fingers, helping move the fingers from side to side. It also transmits feeling from the skin of the outer part of the hand, including the little finger and the outer half of the back of the hand, palm, and ring finger.

Compression of the Ulnar Nerve will generate numbness in the outside of the hand and especially in the little and ring fingers, but can also cause problems to the wrist, shoulder, neck and back. Most Ulnar Nerve problems are caused by upper latching, too low an upper chest wrap, or too high a lower chest wrap.

Compression of the Brachial Plexus itself can also generate all the above mentioned effects because it is the root to the three nerves. Care should be taken when placing tight wraps around or over the top of the shoulders or the sides of the neck. 

Median Nerve

1. Throwing and catching – one arm at a time, throw an imaginary ball underarm palm up, and then catch the ball overarm palm forwards 15 times.
2. One hand juggling – one arm at a time, throw the imaginary ball up and catch it in the same hand 15 times.
3. Three ball juggling – with both hands, juggle three imaginary balls 20 times concentrating on the flow and position of the balls.
4. Far and near – in Tai Chi style, slowly and methodically push out both arms with the palms forwards, fingers up and pull back with the palms backwards slightly facing up, fingers towards each other 15 times.
5. Rolling wave – in Tai Chi style, slowly roll the arms forwards in a large circular wave. At the bottom of the wave the palm faces up and the wrist slowly rotates on the outwards downwards stroke to face the palm out. One arm at the top of the wave as the other is at the bottom. At the same time slowly tilt the head forwards and backwards 20 times.

Radial Nerve

1. Rolling rotation – arms extended horizontally forwards, compress an imaginary ball in each hand and slowly rotate the arms fully clockwise and anticlockwise 10 times.
2. Waiters tip – keep the arm straight and close to the side, angle the arm back with the hand rotated palm upwards as if to accept a tip from behind. Slowly tension by moving the head forwards and backwards 10 times.
3. Wall stretch – extend the arm horizontally to the side and place the palm with the fingers down flat onto a wall. Tip the head forwards and backwards slowly 10 times, and then tip the head side to side slowly 10 times.

Ulnar Nerve

1. Carrying the tray – with the arm to the side, bring the hand up, palm facing up, as if carrying a tray. Touch the shoulder with the fingertips. Slowly rock the head side to side 10 times.
2. Pinkie stretches – arm horizontal to the front, bend the forearm vertical. Grab the little and ring fingers with the other hand and slowly stretch forwards and down, bending the fingers backwards. Tilt the head forwards and slowly return head and forearm 10 times. Repeat, but tilt the head back 10 times.
3. The mask – index fingertips to the tips of the thumbs to make a circle, roll the hands backwards and bring the circles to the eyes like a mask. Tilt the upper body slowly side to side so the elbows face the ceiling 10 times.
4. Full roll – in Tai Chi style, slowly push the hand away from the chest palm forwards and fingers pointing across the chest and sweep the arm around and down to the side. Imagine holding a tray from underneath on the palm and rotate the tray backwards, up, and forwards until presented in front of the face 5 times.

Preparation – derived from Japanese Anma muscle and nerve manipulation, rather than pulling the arms around the side of the body into the small of the back before tying, take each arm forward and high. Rotate the left hand clockwise (seen from behind), so the palm faces up, and then arc the arm back into the small of the back. Repeat with the right arm (rotating the right hand counter–clockwise). Because the Radial Nerve moves with muscle flex, this helps it to be better protected in the upper arm.

The wrist cuff wrap using any non–slip knot forms a loose shelf for the retained forearms to sit in the small of the back. Care should be taken as to the complexity, especially in regard to release time, and to avoid crossing or uneven ropes. Some cuff knots are directional, and will generate a small amount of angular strain as the vertical spinal rope stem pulls upwards. Some are bidirectional, can be tied with a fast-release loop, and function effectively with two or three wraps, providing better support. Any reported numbness generated in the Brachial Plexus network can be instantly relieved by pulling a fast-release loop, allowing lowering the arms to reduce tension on the chest wraps.

Arm positioning – when the forearms are parallel, one in front of the other with the wrists facing backwards and avoiding the cuff wrap directly over the exposed wrist the rotational alignment will push the Radial Nerve slightly deeper away from the surface of the bicep muscles, as will crossing the arms lower than horizontal. Elevated crossed arms on the back will add stress, as will rotating the arms to face the wrists together pushing the Radial Nerve on the arm facing inwards back towards the surface. Everyone will have a preferential position that is commonly different left-to-right. Avoid relaxing (scissoring) the hands downwards, as this will tighten the wrap at the wrists.

Upper latches – these are often the source of nerve problems. There are alternative methods to retain the upper chest wrap securely: either from the second line of the lower chest wrap up between the breasts, over the upper chest wrap and back, or from the returning lower latch lines in the same fashion over the rear armpit areas, or by using bra-strap lines over the shoulder and returning under the lower latches or bra-strap wraps passing over the upper chest wrap at the upper arm, crossing between the breasts, and returning again under the lower latches.

Rope–to–rope connections – even tying the same person the same way with the same ropes may result in the connection point between ropes moving to different positions. Avoid the bulk of the knot over the outside of the arms. In the case that the knot is the front of the chest wraps, stress can be alleviated by rotating the connecting loop so that it sits against the skin and the knots face outwards. To finely adjust the position that the knot will sit, or realign the knots, wrap the rope/s around the vertical stem over the spine to shorten the line/s. If the upper chest wrap is comfortably tight and horizontal at the rear, this will provide enough exposed vertical stem to do this.

Lower latches – these provide the final tension to the lower chest wrap and mean that the wrap itself does not have to be tight, as the latches can be used to increase and balance the tension left to right. A correctly tied chest harness will be perfectly secure without being painfully tight, and you should be able to get two fingers comfortably under the wraps over the arms when complete.

Disclaimer:
 We would like to point out that we are not medical professionals. All advice is from decades of experience.
These notes on the Brachial Plexus nerve branch regarding the chest harness are merely a guide. If you suffer detrimental effects from tying anywhere on the body you should consult a qualified medical professional involved in the specific related area.