This Months Popular science has a nice article about the tech advances in the ER room.
One part of the article made me write up this post
I quote (Popular Science Oct 2003 edition Page 64)
So, why is the considered the quickest and most practical way to check for indications of spinal injury?
Thanks for the help in advance
Osip
Loss of tone (i.e. inappropriate relaxation) of the anal sphincter may indicate spinal cord disease/trauma.
Another interesting test is the bulbocavernosus reflex - To wit: while a finger is inserted into the rectum, the tip of the penis is squeezed!A normal response (indicating intact spinal cord function) is relflex constriction of the anal sphincter.
The E.R. is a fun place!
That anal sphincter is innervated by the tenth cranial nerve, called the Vagus nerve. Loss of sphincter tone means that nerve is damaged. The same cranial nerve plays a role in controlling the diaphram. So obviously that’s not a nerve you want damaged.
The “handshake” can also identify occult blood or internal bleeding, a high riding prostate (indicating the unrethra has suffered trauma). There are several other things the shake is good for. But those are the two big ones in a trauma situation.
It’s a cranial nerve not a spinal nerve, though. So it is more likely to indicate a problem inside the head - like bleeding or swelling in the brain, than a problem with the spinal cord. The nerve runs outside of the spinal cord.
The rectum is innervated by the sacral nerves from the spinal cord, S2-S3. These are parasympathetic fibres, but are NOT connected to the vagus nerve as mentioned above, even though this is also parasympathetic.
The trauma handshake is an important part of a complete physical exam, but too often not done. The diaphragm is controlled by the phrenic nerve, innervated at levels C3-C5 of the cervical spine. The vagus nerve does not innervate the diaphragm either.
The handshake is one part of a spinal exam. It is often less important than palpating the spine and “clearing the neck”, but it can give the other info Bear_Nenno mentioned in the first post before she got on her little vagus fixation. The Vagus is important, but it does not wander as much as implied!
I am just a load of half information today. The fact that the article said “spinal injuries” made me check my notes. I only have a 90% average so maybe that’s part of the 10% or things I got wrong. Anyway, it appears the sacral nerves, S3, S4, S5 at the bottom of the spinal cord control the dermatones (sensory region) in that area. The Vagus controls the motor part of the equation. So injury to either the head or the spinal cord would cause a lack of tone.
damn simulposts… so maybe i am more wrong than i thought. I know the phrenic nerve controls the motor part of the diaphram. But doesnt the vagus play a sensory role there?? Like with stretch receptors or something
“Motor innervation of the external anal sphincter is via the inferior rectal branch of the pudendal nerve and the perianal branch of the fourth sacral nerve. The internal anal sphincter has sympathetic (motor) and parasympathetic (inhibitory) innervation. Parasympathetic supply is from the nervi erigentes (S2, S3, S4). Sympathetic innervation is from the first three lumbar segments via the preaortic plexus.”
The vagus plays a vague role in the “enteric nervous system” which is thought to help provide peristalsis. But it doesn’t get as far down as you think.
Other things to look for on a rectal trauma exam include edema (swelling), bruises, lacerations, deformities, palpation of bony prominences to suggest fracture (Earle’s sign), displacement of the prostate, decrease in sphincter tone and urological injury.
I don’t think the vagus plays an important role in the diaphragm, it might play a minor role.
Speaking of nerves which control the anal sphincter: once every few months I suffer from something called Proctalgia Fugax and what this means is that I wake up in the middle of the night with pain due to a spasm of the anal sphincter. There’s nothing I can do about it but stand up and walk around until it goes away by itself which may take 30 minutes or more, by which time I am wide awake and take forever to get back to sleep so the night is ruined. I have no idea what causes this and it happens so infrequently that it is difficult to pinpoint what may be the cause.
Anyone know what may be the cause and how it may be treated?
Hmm…[checks]. I’ll be damned, you’re right!!
(Of course, now I have to check out that “keyboard cleaning” thread…)
Come recite the mnemonic with me:
“S 2, 3, 4
Keep the penis off the floor!”
Nice one. My favorite, of course, is Ooh Ooh Ooh To Touch And Feel A Girl’s Vagina, So Hott.
But apparantly it didn’t do much for teaching what the damn nerves are responsible for.
I knew there was a reason I went to law school instead of med school. :o :o :o
Sorry, but purely in the interest of science, is a female just out of luck when it comes to this bulbocavernosus reflex text?
Damn you beautiful bastards.
I suspected to get a correct factual answer. Thank you all. Now I can quit wondering about it.
Of course, I do have to say I expected 4 or 5 posts before a solid factual answer came in.
How wrong I was. I suspect I shall never underestimate the Straight dope GQ Forum.
My favourite two mnemonics:
To remeber the §parasympathetic system is responsible for erections and the (S)sympathetic system for ejaculation:
Point and Shoot
To remember the little bones of the hand:
Tender Tits Can’t Hurt So Love Them Passionately.
Point and Shoot. LOL
The one I learned for the bones in the hand was - starting at the scaphoid:
Some Lovers Try Positions That They Cant Handle.
The girls in our class came up with their own version:
Tremendous Testicles Can Hang Significantly Lower Than Penises.
Oh. proctalgia fugax is thought to be caused by spasm of the levator muscles. This differs from other pains in the ass by being transient, deep seated (hrrrmph) and unrelated to defecation.
Like other spasms, blood work is usually normal although it can be caused by skewed levels of potassium, calcium, etc. Muscle relaxants or calcium channel blockers would possibly help them, if they occurred often enough to warrant a medicine.