FEMORAL NERVE

This is not a highly academic dissertation on the anatomy of the Femoral nerve but rather how the mid and upper lumbar spine relates to Chiropractic practice.

The upper lumbar plexus supplies five major nerves and some smaller ones, all of which overlap giving off small branches which connect with each other, making the precise diagnosis of the pain patterns difficult. Fortunately, in Chiropractic practice, it's not usually necessary to make a decision whether the entrapment is of the Femoral nerve or the IlioInguinal nerve, for example. Medicine does it by injecting nerve blocks - if the pain stops, then it must have been the XXX nerve.

1. Ilio hypogastric nerve (T12-L1)

2. Ilio inguinal nerve (T12-L1)

3. Genito femoral nerve (L1-L2)

4. Lateral Femoral Cutaneous nerve (L2-4)

5. Femoral nerve (L2-L3-L4)

It’s very easy to download this PDF file, no special Kindles etc are necessary.

FEMORAL NERVE (L2-L3-L4)

The Femoral nerve emerges from the mid-upper lumbar spine, whereas the Sciatic nerve emerges from the lower lumbar spine.

Both course down just in front of the spine, through the pelvis, but the Sciatic nerve emerges through the sciatic foramen, passing into the buttock and the back of the thigh and calf, and the outer side of the lower leg and the foot.

But the Femoral nerve passes through the groin supplying the

• SENSORY innervation to the skin of the upper anterior thigh (front of the leg), the distal medial thigh, the knee joint and sometimes the medial (inner) lower leg.

• MOTOR innervation to the Quadriceps and Ilio-psoas muscles. The patellar tendon reflex gives an important measure of the integrity of the Femoral nerve.

FEMORAL NERVE ENTRAPMENT

Because it is a "mixed" nerve, injury to the Femoral nerve can cause both sensory disturbance (including pain) AND motor weakness of the Quadriceps and Ilio-psoas muscle.

An aside: Diabetes has a predilection for the Quadriceps muscle. Remembering that approximately half of diabetics are undiagnosed, NON-PAINFUL weakness of the Quadriceps muscle, particularly if associated with the typical diabetes symptoms of thirst, weight loss and inability to gain an erection, ALWAYS calls for a blood sugar test.

More typically the patient presents with PAIN, sometimes sensory disturbance (early-on increased sensation, later numbness) and, in more serious cases, loss of the knee jerk reflex and weakness of Hip flexion and Knee extension.

Weakness of the Quadriceps and Iliopsoas causes a marked limp.

CAUSES OF ENTRAPMENT

• LUMBAR SPINE PATHOLOGY

  Both a slipped disc in the mid-lumbar region, and a facet syndrome may cause severe back pain and radiating pain to the anterior thigh and sometimes lower inner leg.

  When the Quadriceps muscle is affected, you may find that the knee "gives" or buckles. People may remark that you are limping badly. Your chiropractor will find a diminished or absent knee-jerk reflex.

  Notice the blue (sensory) and red (motor) nerves to the Quadriceps muscle...

  
  
  

  

  
  
  

• ABDOMINAL ABSCESS, TUMOURS AND TRAUMA

  Very occasionally, an abscess (such as in TB), abdominal tumours and a sudden bleed by patients on anticoagulants may physically press on the Femoral-nerve causing pain and weakness in the thigh.

  An aside: Always there's a trade-off between the benefits of treatment (and that includes Chiropractic Help) and the potential side effects. Today I heard that a patient aged 83 couldn't come for treatment: anti-coagultant therapy caused a nose-bleed so bad that she's been hospitalised. And last month a very special favourite patient (yes, all doctors have favourites!) went in for routine laser treatment for an eye condition. The surgeon didn't ask what drugs she was on - the anti-coagulants for a minor heart condition caused a bleed behind the retina, and now she's permanently blind in one eye. Only 55-years old.

  
  
  

• MEDICAL PROCEDURES and other...

  Needle puncture procedures, abdominal and inguinal surgery, total hip replacement, harvesting of bone chips from the ilium, a difficult childbirth, pelvic fractures, cancer radiation and other trauma to the groin (knife wounds, for example) and pelvis and upper leg all can occasionally injure the Femoral-nerve.

CHIROPRACTIC COALFACE

Clearly, a thorough case history and examination is vital in all cases of groin and anterior thigh pain.

HIP ARTHRITIS too, also typically causes groin pain radiating down the anterior leg to the knee, but with very different signs so that the astute clinician would have no difficulty making the differential diagnosis.

INTERESTING RESEARCH (Clin Ortho 1975 May;(108))

Of 455 patient treated surgically for lower back and leg pain, 10% were found to have syndromes affecting the Femoral-nerve, and 90% the Sciatic nerve.

Interestingly, those with Femoral nerve conditions were on average more than ten years older than the Sciatic nerve group.

The reason? The Femoral nerve group - the older group - had lesions of the facet joint associated with aging and arthritis, rather than disc injuries, which were more common in the (younger) sciatic nerve group.

Notice that the foramen from which the nerve emerges is bounded anteriorally by the disc (on the right) and the facet joint posteriorally (left). Both can impinge on the nerve roots.

1. "The higher level of the lesion the greater theincidence of apophyseal (facet) joint arthritis which may be associated with the aging process."

2. "The femoral distribution of pain may lead to difficulties in differential diagnosis between a spinal origin and a hip or knee origin of the problem." Hip conditions too typically cause pain in the groin radiating towards the knee.

3. "Radiculopathy causing femoral pain may be the result of both disk degeneration with protrusion and apophyseal (facet) arthritis with synovitis." A meniscus-type entrapment.

4. "Neuritis of the L4 nerve root is more commonly the result of a lesion at the L4-5 nerve root foramen than centrally at the L3-4 disk level."

5. "The syndrome of low back pain with femoral neuritis is NOT UNCOMMON 5 or more years after an otherwise successful L4-L5-S1, two-level spine fusion."

Point number 4 above is vital for the Chiropractic physician. A facet syndrome at L4-L5 will affect the L4 nerve root, but a disc lesion at L3-L4 would be the cause of a L4 neuritis. Successful treatment is predicated on making the correct diagnosis and treating the correct level.

CHIROPRACTIC HELP

Successful outcomes may be dependent on BOTH sites of impingement being addressed. In short, is your chiropractor also busy in the groin/ upper thigh?

MERALGIA PARESTHETICA

ILIO-INGUINAL nerve

A facet injury at T12-L1 can cause pain in the groin and scrotal areas, as well as a Maignes syndrome ... Once again, addressing both the spinal lesion and an entrapment in the groin as the Ilio-inguinal nerve passes into the inguinal canal may be important.

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