Why do we get sciatic pain?

Sciatic pain is for sure one of the most debilitating and annoying conditions that can affect our lower back.

Sciatic pain is a symptom that can affect our ability to walk and seat properly.

Generally, sciatic pain increases its intensity during the movement of bending down of our body or lifting the legs.

Sciatic pain is a common issue with people with a desk job and not quite active lifestyle but It can affect people with a quite active job and lifestyle too.

Sciatic pain or Sciatica is a condition that is represented by the inflammation or irritation of the Sciatic Nerve.

The symptoms of sciatica can be localized in different areas of our body causing lower back pain, hip pain, and leg pain.

Sciatic Nerve Anatomy

The sciatic nerve is part of the sacral plexus and it arises from the anterior rami of spinal nerves of L4 through S3.

The sciatic nerve is more precisely composed by:

  1. The lumbosacral trunk that includes the nerves L4 and L5
  2. Part of the Sacral Plexus that includes the nerves S1, S2, and S3
Sciatic Nerve Anatomy

Sciatic Nerve Anatomy

The sciatic nerve runs down the posterior leg and it bifurcates into two terminal branches at the apex of the popliteal fossa:

  1. Tibial Nerve ( formed by anterior division of spinal nerves L4-S3 )
  2. Common Fibular Nerve ( formed by spinal nerves L4-S2 )

The Tibial Nerve innervations:

Posterior Compartment of the Tigh:

  1. Semitendinosus Muscle
  2. Semimembranous Muscle
  3. Long Head of Biceps Femoris Muscle
  4. Ischial part of Adductor Magnus Muscle

Posterior Compartment of The Leg:

  1. Gastrocnemius Muscles
  2. Plantaris Muscle
  3. Soleus Muscle
  4. Popliteus Muscle
  5. Flexor Digitorum Longus
  6. Tibialis Posterior
  7. Flexor Allucis Longus Muscle

The Tibial Nerve divides into terminal branches:

  1. Sural Nerve formed by fibers derived from spinal S1 and S2 nerves ( Nervus Suralis )
  2. Medial Plantar NerveLateral Plantar Nerve
  3. Medial Calcaneal Branch ( Rami Calcanei Mediales )
  • Sensory Innervation to the lower posterolateral aspect of the leg and foot
  • Motor Innervation of the foot’s muscles

The Common Fibular Nerve Innervations:

Posterior Compartment of the Tigh

  1. Short Head of Biceps Femoris Muscle

Posterior Compartment of The Leg ( lateral Side of the Leg )

Superficial Fibular Nerve ( Nervus Fibularis Seperficialis )

  1. Fibularis Longus Muscle
  2. Fibularis Brevis Muscle

Deep Fibular Nerve ( Nervus Fibularis Profundus )

  1. Tibialis Anterior Muscle
  2. Extensor Allucis Longus Muscle
  3. Extensor Digitorum Longus Muscle
  4. Extensor Digitorum Brevis Muscle
  5. Extensor Fibularis Tertius Muscle

 

The common Fibular Nerve, also known as a Common Peroneal Nerve provides sensory and motor innervations to the Posterolateral leg.

The Fibular Nerve divides into two terminal branches that innervate for the foot’s muscles:

  1. Superficial Fibular Nerve that provides motor innervations to the lower leg’s muscles and foot:
  • Fibularis Longus Muscle
  • Fibularis Brevis Muscle
  • Sensory innervation to the skin of the lower leg and dorsum of the foot

       2. Deep Fibular Nerve that provides motor and sensory innervations to the anterior compartment of the leg.

Anatomic Route of the sciatic nerve:

The Sciatic Nerve emerges from the pelvis below the piriformis muscle and lies on Gemellus Superior Muscle, Obturator Internus Muscle, Gemellus Inferior Muscle, and Quadratus Femoris Muscle.

It enters the thigh between the ischial tuberosity and the greater trochanter and goes down the back leg lying on the Adductor Magnus Muscle and surrounded by the Semimembranous Muscle, and Biceps Femoris Muscles.

Causes of Sciatic Pain

The inflammation of the sciatic nerve has mainly two principal causes:

  1. Bulging or Herniated Disc.
  2. Nerve impingement along the way down from the spine during the passage between muscles.

A bulging disc is a more common and milder condition than a herniated disc. It is often only a temporary condition due to overstress of the spine and its vertebras. 

A bulging disc consists of a load of the disc between the two vertebras and consequent partial compression of the nerve that comes out from the spine.

The herniated disc consists instead of a complete collapse of the disc with consequent complete compression of the related nerve.

Other less common causes of sciatic pain are:

  1. Facet Joint Inflammation
  2. Stenosis of the foramens
  3. SI Joint Pain

Where can occur sciatic nerve compression?

There are mainly two critical areas where the sciatic nerve can be squeezed and compressed:

  1. Compression of the sciatic nerve can occur at the level of L4-S4 of the spine.
  2. Area of the femur-glenoid joint compressed from piriformis muscle ( Piriformis Syndrome )

A protrusion of a lumbar intervertebral disc usually does not impede the exit of the nerve above the disc.

A lateral protrusion of the intervertebral disc at the level of Lumbar Vertebra 4 and 5 impedes the L5 nerve and not the L4 nerve.

A protrusion of the intervertebral disc at the level of Lumbar Vertebra 5 and Sacral Vertebra 1 impedes the S1 nerve and not the L5 nerve.

A paramedian protrusion of the intervertebral disc at the level Lumbar Vertebra 4 and 5 rarely impinges the L4 nerve, but may impinge L5 and sometimes S1-S4 nerves.

 

Another area where the sciatic nerve can be compressed is the area of the Ischia spine where it lies on and runs down the leg exiting below the piriformis muscle.

There are various genetic variations in some individuals in which the sciatic nerve could run in the middle or on the top of the piriformis muscles too.

If the piriformis muscle is too tense for some reason, it can compress the sciatic nerve and irritate it.

The sciatic nerve entrapment can be caused not only by the piriformis but by other structures such as fibrous bands containing blood vessels, gluteal muscles, hamstring muscles, Gemelli Obturators Internus complex, vascular abnormalities, and space-occupying lesions. 

For this reason, we prefer now to use the term “Deep Gluteal Syndrome” instead of “Piriformis Syndrome”.

Sciatic pain areas and symptoms

The irritation or inflammation of the sciatic nerve can cause pain in different areas of our lower back and leg accordingly with its compression areas.

If there is a bulging or herniated disc at the level of the lumbar tract of the spine likely there will be shooting pain down the leg and foot of the affected side.

If the irritation or inflammation is caused by the Deep Gluteal Syndrome or Piriformis Syndrome the areas of pain will be more localized around the gluteal area.

That's how to treat and cure sciatic pain

The treatment and the cure for sciatic pain depend on the cause that has generated sciatic nerve entrapment or irritation.

If the main cause of sciatica is a bulging disc, this generally, can be resolved with hands-on treatment like sports massage and physio techniques to ease the tension of the muscles of the lumbar tract of the spine and to decompress the discs between the spinal vertebras.

Stretching exercises can help to reduce muscle tension and decompress the lumbar tract of the spine and the deep muscles of the femur-glenoid joint.

If the cause of sciatic pain is a herniated disc, the treatment could be a surgical one.

When the cause of sciatic pain is due to Deep Gluteal Syndrome, strengthening exercises for the muscles of the femoral-glenoid joint, together with stretching exercises, is the long-term plan to reduce the risk factors of sciatica.

We advise asking for the help of your trusted sports therapist or physiotherapist to identify the origin of the sciatic pain.


The ideal back pain treatment aims to treat both the root causes and symptoms that have caused it.

They can assess the main cause of sciatic pain by performing simple tests such as FAIR Test ( Flexion, Adduction, Internal Rotation ), SlumpTest, and Bowstring Test.

One Comment on “Why do we get sciatic pain?

  1. Pingback: Herniated and Bulging Disc: Diagnosis, causes and treatments - Mr Salus Sporting Lab

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