22. as jose was running down the road, he tripped and his left ankle

twisted violently to the side. when he picked himself up, he

was unable to put any weight on that ankle. the diagnosis was

severe dislocation and sprains of the left ankle. the orthopedic

surgeon stated that she would perform a closed reduction of the

dislocation and attempt ligament repair by using arthroscopy.

(b) what does its

stability depend on? (c) what is a closed reduction? (d) why is

ligament repair necessary? (e) what does arthroscopy entail?

(f) how will the use of this procedure minimize jose's

recuperation time (and suffering)?

The ankle joint is a pretty weak one when it comes to stability, mainly because aside from being formed by different types of bones, it is only stabilized by ligaments, instead of fully formed muscles. The reason for this is that the ankle joint needs to freely move in different planes, and if it depended on muscle, then that movement would be restricted much more.

Knowing this, we look at Jose´s case, and the answers would be as follows:

1. The stability of the joint, as said before, depends entirely on ligaments, making it more fragile and vulnerable than other joints.

2. A closed reduction is a surgical procedure in which, without having to literally cut the zone open, and through the use of arthroscopic devices, the surgeon may align the dislocated bones again so that they can seal themselves naturally.

3. Jose did not just have his bones dislocated, but the ligaments were sprained, which means, they too, were affected by the sharp movement. This means that the joint does not have any form of stability because the ligaments cannot hold the bones together. Thus, ligament repair will restore these tissues to their proper place, allow them to heal, so that later on José can use the joint again.

4. Arthroscopy is a really minimally invasive procedure in which the surgeon uses an arthroscope, literally like an endoscopic tube, but specific for joints,  and which allows the surgeon to repair the damage in the joint, without having to make any major incisions. It entails the making of a keyhole, or small, incision through which the tube-like device, with the necessary instruments for repair, will be pushed into the joint.

5. First, the smaller the incision made, the lesser the possibility of infection for José. Second, there is less manipulation of the zone, and therefore the inflammation process will recede much faster. Third, the realignment and reconstruction of the ligaments and bones, with a lesser inflammation process, will allow the joint to be able to recuperate much faster.  

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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answer: c

explanation: