The sciatic nerve is formed through a combination of motor and sensory fibers based on the spinal nerves of the lower back L4 to S3, known as the lumbosacral plexus. It is the largest and longest nerve in the human body and about as wide as an adult thumb. It begins at the base of the spine, runs along the back of each leg, and ends at the foot supplying the areas with fresh blood and nutrients. There are sciatic nerve branches that consist of primary branches and smaller branches.

Sciatic Nerve Branches

• The nerve splits into two main branches near the back of the knee called the popliteal fossa.
• This fossa is located slightly above the joint behind the knee.
• The popliteal fossa is a diamond-shaped space that acts as the conduit for the blood vessels and nerves.

Primary branches

From the popliteal fossa:

• The tibial nerve continues down the back of the calf to the heel and bottom of the foot.
• The common peroneal nerve, aka common fibular nerve, travels sideways along the outer part of the knee to the outer border of the lower leg and foot.
• Both nerves convert into small sensory nerves in the calf that supply the outer side of each foot.
• These sensory nerves are called sural nerves.

Collateral branches

The sciatic nerve breaks off into smaller branches, known as collaterals, that include:

• These are muscle branches that supply the muscles in the thigh, including the hamstring group and the adductor magnus muscles along the inner thigh.
• Other small branches supply the leg and foot muscles.
• Articular branches supply the back of the hip joint, the back and side of the knee joint.

The sciatic nerve does not supply structures in the buttocks; however, pain commonly radiates/spreads into this area when the nerve is impaired, impinged, and inflamed.

Blood Supply

The delivery of nutrients to the sciatic nerve is done through blood vessels that also contribute to the nerve’s function. Any interruption of blood flow to the sciatic nerve can cause pain and dysfunction. The sciatic nerve and the sciatic nerve branches receive their blood supply from two sources that include:

• The extrinsic system is made up of nearby arteries and veins.
• The intrinsic system includes arteries and veins that run along the nerve and are embedded deep in a sheath known as the epineurium of connective tissue that envelops the nerve.
• The intrinsic blood supply can be affected by conditions like diabetes, which can contribute to symptoms associated with diabetic neuropathy.
• Both systems connect at various junction points.

Nerve Function

The combination of sensory and motor fibers that make up the sciatic nerve provides the essential functions in the lower limbs allowing the body to:

• Stand
• Walk
• Run
• Climb
• Lift

A healthy sciatic nerve is well protected around the low back and buttock muscles where it starts, and it cannot be palpated or felt by touching or pressing on the area. When the nerve gets inflamed, injured, or pinched, the leg can feel stiff and inflexible when trying to move and can lead to pain, weakness, and tingling in the lower back, buttock, leg/s, and feet.

Anatomical Variations of the Nerve

Individuals can have variations in the anatomical structure of the sciatic nerve. These variations are considered normal, but they can increase the risk of developing sciatica brought on by impingement, entrapment, or irritation of the nerve root/s. Variations in sciatic nerve branches include:

• The nerve divides above the piriformis muscle; one portion passes through the piriformis, with the other portion exiting the pelvis below the muscle. This is the most common variation.
• The nerve divides above the piriformis muscle; one portion passes through the piriformis, with the other portion exiting the pelvis above the muscle.
• The nerve divides above the piriformis, with one portion traveling in front while the other travels behind it.
• Undivided sciatic nerve exits through the piriformis muscle.
• Undivided sciatic nerve exits from behind the top part of the piriformis.
• Around 10% of individuals have a nerve that divides above the popliteal fossa and does not merge but courses down in two separate branches.

The sciatic nerve and the sciatic nerve branches are significant components of the body. It supplies motor functions to move the legs and feet and provides sensory functions along the nerve path. Keeping the sciatic nerve healthy is key in helping to prevent back and spinal issues. Chiropractic can help realign the sciatic nerve and educate on maintaining the nerve’s health.

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Body Composition

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Fitness Motivation

New workout routine

Individuals that don’t feel like returning to previous workout routines are recommended to try out other fitness options. If the gym isn’t cutting it or there is burnout with the current routine, switch things up. This can include:

• Virtual group classes.
• 1-on-1 personal training.
• Outdoor activities.
• All are valid options to explore if in a rut with the current routine.
• The important thing is to find what works for you.

Allow the body to rest

Individuals may want to push it to the limit to get back into shape, but rest days are essential for healthy muscle development and improved performance.

• Noticing the body is more sore and exhausted after a workout is an indication that the body needs rest. This also includes:
• Maintaining proper hydration.
• Stretching out the muscles regularly.
• Taking days off from exercising are necessary to:
• Prevent muscle fatigue.
• Reduce the risk of injury.
• Allow for adequate muscle recovery.

Long term commitment is key

It can be discouraging to commit to a workout schedule only to notice minor changes to strength and fitness.

• However, small improvements do accumulate over time.
• Small increases over time can have a huge impact on overall strength and fitness.
• Keep the bigger picture in mind to remain positive.

References

Davis D, Vasudevan A. Sciatica. [Updated 2019 Feb 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Available from: www.ncbi.nlm.nih.gov/books/NBK507908/

Barral J, Croibier A. Manual Therapy for the Peripheral Nerves. Elsevier Health Sciences; 2007.

Ryan MM, Jones HR Jr. Mononeuropathies. In: Neuromuscular Disorders of Infancy, Childhood, and Adolescence. Elsevier; 2015:243-273. doi:10.1016/b978-0-12-417044-5.00014-7