Somatic Nerves – Posterior Abdominal Wall

by James Pickering, PhD

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    00:00 So if we remove the organs, the kidneys, the spleen, the pancreas the suprarenal glands. If we remove all the organs within the abdomen and all the arteries and their branches and we are just left with the muscles. We can see a whole series of beautiful nerves which are radiating away from the spinal cord through the intervertebral foramen.

    00:21 And we have a number of these somatic nerves.

    00:25 And these contain sensory and motor fibers that supply the skeletal musculature and the skin of the abdomen.

    00:34 So these are containing sensory fibers that are taking cutaneous information back from the skin and also motor fibers that make the muscles contract.

    00:46 As a somatic nerve that's passing to the body wall there is also going to be some sympathetic fibers that control the hairs, that control the sweat glands.

    00:55 But we don't have any parasympathetic input.

    00:59 These nerves that are running down to the posterior abdominal wall and we can see a few here. We have got a subcostal nerve, this is T12.

    01:08 That's the most, that's the last nerve to originate from the thoracic segment of the spinal cord.

    01:17 Then we have iliohypogastric and ilioinguinal. These are both derived from the L1 spinal cord segment iliohypogastric and ilioinguinal.

    01:27 We can then see we have the genitofemoral nerve.

    01:30 The genitofemoral nerve is passing out through the psoas major here.

    01:36 And the genitofemoral nerve splits into a genital branch and into a femoral branch. And these two blood vessels these two nerves pass through the psoas major one then runs along the inguinal canal runs within the spermatic cord of the inguinal canal to supply the skin around the scrotum around the labia if it’s in the female.

    02:04 And the femoral branch passes through the fascia of the thigh to supply discreet region on the anterior surface of the thigh.

    02:13 The genitofemoral nerve comes from the L1 and L2.

    02:17 We also have the lateral cutaneous nerve of the thigh, which we can see radiating down here.

    02:24 We can have the obturator nerve. The obturator nerve is really important coming from L2 L3, L4. And that supplies the adductor portion of of the musculature in lower limb. The adductor, the medial portion, it leaves the pelvis by passing through the obturator foramen and the obturator canal.

    02:43 which is the defect in the obturator fascia. So it runs along the lateral wall of the pelvis.

    02:48 And we can pick up obturator nerve coming down in this direction.

    02:53 and see it passing through obturator canal. That's important, like I said to supply the medial compartment. We also have the femoral nerve L2, L3, L4 again.

    03:04 And the femoral nerve which we can pick up here is quite a large branch it runs lateral to the psoas major muscles and it extends down into the anterior compartment of the thigh where it goes on to supply the anterior musculature of the thigh so rectus femoris and your quadraceps.

    03:24 We also have the lumbosacral trunk which is from L4 to L5.

    03:29 So we can see we have a whole series of nerves radiating along the posterior abdominal wall which are really important in maintaining the function of the muscles within the posterior abdominal wall and elsewhere; and carry important sympathetic fibers to the body wall as well.

    03:48 It'll also going to be containing cutaneous information via the sensory fibers taking information about pain, touch, temperature back to the central nervous system.

    About the Lecture

    The lecture Somatic Nerves – Posterior Abdominal Wall by James Pickering, PhD is from the course Abdomen.

    Included Quiz Questions

    1. Genitofemoral
    2. Femoral
    3. Iliohypogastric
    4. Ilioinguinal
    1. L2, L3, and L4
    2. L1, L2, and L3
    3. L3, L4, and L5
    4. T12, LI, and L2
    5. LI and L2
    1. Femoral
    2. Genitofemoral
    3. Inguinal
    4. Obturator
    5. Sciatic

    Author of lecture Somatic Nerves – Posterior Abdominal Wall

     James Pickering, PhD

    James Pickering, PhD

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    Lumbar Nerves
    By Astrocyte C. on 19. October 2017 for Somatic Nerves – Posterior Abdominal Wall

    For the slide about the lumbar nerves, only subcostal (T12) is listed. It would be helpful to list other nerves, such as iliohypogastric (T?) and ilioinguinal (T?).