Medical If your wrist is under anaesthetic how would your fingers/palm feel?

[atjta]

Like if only your wrist was put under anaesthesia, would your palm and fingers immediately lose feeling too? Or would they be partially numb? Or what?

 

[Lievo]

Interesting question, but a very theoretical one. The only methods I'm aware off to anesthetized the wrist is either ischemia or blocking nerves conduction. In both case, you'd anaesthetized not only wrist but also anything below.

 

[bobze]

Depends on where you are talking "wrist". Most people refer to their wrist as the distal part of their forearm. The true or anatomical wrist is actually what you'd probably consider the base of your hand. If you are talking about the former;

Anterior wrist sensory information is via the lateral antebrachial cutaneous nerve (terminal branch of the musculocutaneous), the medial antebrachial cutaneous nerve (a branch of the medial chord of the brachial plexus) and a small central strip on the posterior surface via the superficial branch of the radial nerve. Each of these cutaneous nerves could be blocked with locals (6-8H) if you were only doing something superficial, like sutures and sensation in the fingers would be retained.

Because these nerves can be hard to find, the main nerve can be blocked (which lasts up to 24H) to ensure sensation is temporarily lost.

For the anatomical wrist, this is innervated (the skin over the thenar and hypothenar components) by superficial branches of the ulnar and median nerves. Because these superficial branches are small normally the distal ulnar and median nerves are blocked near the proximal wrist crease. Which would cause sensation in the fingers to be lost as well (fingers are innervated, cutaneously, by digital branches from the ulnar and median nerves).

If something like hand surgery is being done, the ulnar, median and radial are normally blocked (24H) more proximally in the forearm. Where sensation in the fingers would be lost temporarily.

**Note; antebrachial is anatomist/doctor speak for "forearm", from your elbow to your "true" wrist.

 

[Lievo]

sensation in the fingers would be lost temporarily.

Not all sensations, though. Finger proprioception is largely based on muscle spindle in the forearm, meaning that one can feel despite the finger is anaesthetized. It's strange to write, but was shown http://www.springerlink.com/content/6v5wfqk429l181ul/"

 

[bobze]

Not all sensations, though. Finger proprioception is largely based on muscle spindle in the forearm, meaning that one can feel despite the finger is anaesthetized. It's strange to write, but was shown http://www.springerlink.com/content/6v5wfqk429l181ul/"

Yes, that's true. You're not really stimulating cutaneous GSAs from the fingers though (which is what I think the OP was asking about, the generals), but rather the tendons of the flexor and extensor muscles (flexor carpi superficialis/profundus, extensor digitorum/indicies, and those for the pollicis) which, as you say are housed in the forearm. Its not really surprising that deep sensations are able to elicit a response via the tendons, because they normally have fine afferents (at least major extremity tendons).

Either way, for a deep hand surgery where these tendons are being worked on, you can still anesthetize sensations by doing a proximal block at the level of the elbow. The ulnar and median nerves are both easy to block here (you can actually feel your ulnar nerve on the lateral side of the elbow as it crosses around the lateral humoral epicondyle--You're "funny bone"--, and the median nerve courses under the bicipital aponeurosis next to the biceps brachii tendon in the cubital fossa). Both blocks would block tendon sensation more distally in the upper extremities.Edited to add: Note however, the somatic sensory sensation of the tendons isn't a "typical" pain response, rather a "here's some deep pressure" (more akin to pacinian corpuscle responses). Which is why you can do hand surgeries with only distal nerve blocks (such as the proximal wrist crease), which is done lots for surgeries to cut the flexor retinaculum during carpal tunnel surgery.

 

[fdsaguy666]

Question: does it feel like your fingers are immediately connected to your forearm or does it feel like there's a gap?

 

[hemeliscus]

i'd say it will definitely feel numb.. you won't feel a thing.. you will definitely feel like there's a gap since the drug will temporary "kill" the senses from the wrist down..

 

[SW VandeCarr]

bump

Why the bump? You've already had seven responses including two pretty comprehensive responses from bobze. What are you looking for?

 

[atjta]

Question: does it feel like your fingers are immediately connected to your forearm or does it feel like there's a gap between fingers and arm?

This