Leg anatomy 101 - please help

[Phloston]

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For some odd reason, I'm having a bit of difficulty regarding some stuff I should have known about the first day of MS1.

Common peroneal nerve --> superficial (lateral compartment) + deep (anterior compartment)

Superficial --> peroneus longus + brevis (eversion + plantar flexion)

Deep --> tibialis anterior (dorsiflexion + inversion)

Tibial nerve --> plantarflexion + inversion (tibialis posterior)

Basically the tibialis inverts, but is split between the deep peroneal and tibial nerves, anterior vs posterior, respectively.

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Fistly, is the above correct?

Secondly, if the superficial peroneal nerve has plantarflexion function, do we ever see loss of plantarflexion with that nerve injury, or should I strictly think loss of eversion?

I feel like I'm missing something and need someone who's strong with anatomy to just spell-out what the functions of these two nerve branches are.

 

[DavetheMD]

I feel like going about the nerve pathways without thinking of the muscles is limiting.

For instance, both the Tibialis anterior and posterior are your strongest inverters. Yet, the Tibialis anterior is innervated by the deep fibular nerve and the Tibialis posterior is innervated by the tibial nerve. And they are indeed separate muscles.

Cutting either nerve branch would paralyze or weaken the specific muscles it innervates. But doing so to only one of the nerves, only prevents one muscle from inverting. Make sense?

 

[cbrons]

http://www.med.umich.edu/lrc/course.../modules/lower_limb_module/lower_limb_01.html <-- good module for this here

 

[Phloston]

Thanks, cbrons. That's a really good link actually. Maybe by the time I finish the mini-tutorial, I'll be at the level of most MS1s.

Just finished the tutorial. Very helpful. I also noticed it's a University of Michigan SoM platform, which I found entertaining for some reason.

 

[arez10]

If you injure your superficial peroneal nerve, you are more concerned with loss of sensory to the dorsum of the foot as well as eversion from the peroneal muscles. you will not lose plantarflexion because you have an entire posterior compartment dedicated to that function.