Superior Gluteal Nerve (SGN)
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March 22, 2022
Superior Gluteal Nerve (SGN) entrapment syndrome occurs when injury or lesion occurs to the nerve as it leaves the suprapiriform foramen and its fibers travel parallel to the piriformis muscle. Injury to the SGN is likely the most common local nerve injury, impairment or lesion resulting in pain or paresis of the piriformis muscle, rivalling sciatic nerve entrapment for commonality.
The purpose of this article is to highlight the importance of superior gluteal nerve (SGN) entrapment as a cause of non-discogenic gluteal pain as it exits the extra-pelvic foramen.
Common complaints from superior gluteal nerve entrapment syndrome includes weakness of the hip abductor muscles, weakness of the piriformis muscle, painful palpation of the greater sciatic notch and pain that usually occurs suddenly in the posterior/ lateral gluteal region. This traditionally was thought to be have originated from the piriformis muscle compressing the sciatic nerve, and this article takes an in depth examination of alternative explanations of deep gluteal syndrome (DGS).
Piriformis syndrome is an outdated term and has become a “catch-all” term to errantly describe pain that occurs in the buttock area. In attempt to better describe the possible contributors to buttock pain of neural or muscle origin, some authors have promoted the use of the term Deep Gluteal Syndrome to describe the pain in the buttock caused by non-discogenic and extra-pelvic entrapment of the sciatic nerve(Martin, et al, 2015).
The purpose of this article is to highlight the importance of superior gluteal nerve (SGN) entrapment as a cause of non-discogenic gluteal pain as it exits the extra-pelvic foramen.
Common complaints from superior gluteal nerve entrapment syndrome includes weakness of the hip abductor muscles, weakness of the piriformis muscle, painful palpation of the greater sciatic notch and pain that usually occurs suddenly in the posterior/ lateral gluteal region. This traditionally was thought to be have originated from the piriformis muscle compressing the sciatic nerve, and this article takes an in depth examination of alternative explanations of deep gluteal syndrome (DGS).
Piriformis syndrome is an outdated term and has become a “catch-all” term to errantly describe pain that occurs in the buttock area. In attempt to better describe the possible contributors to buttock pain of neural or muscle origin, some authors have promoted the use of the term Deep Gluteal Syndrome to describe the pain in the buttock caused by non-discogenic and extra-pelvic entrapment of the sciatic nerve(Martin, et al, 2015).
Deep gluteal syndrome includescomplications or injury to the:
1. piriformis muscle
2. fibrous bands in proximity to the superior gluteal artery
3. hamstring muscles
4. gemelli-obturator complex
5. superior gluteal nerve entrapment
6. sciatic nerve entrapment
Once discogenic pathology has been ruled out with the NeuroCentric Approach, the most common cause of posterior gluteal pain is sciatic nerve and/orsuperior gluteal nerve entrapment. The piriformis muscle no longer should be considered as theonly mechanism for posterior gluteal pain. A thorough orthopedic examination of the superior gluteal nerve needs to be evaluated outside of the more common sciatic nerve entrapment, especially when patients are not responding to traditional treatment.
We discuss evaluation methods in NeuroCentric Approach coursework, but here let’s discuss anatomy.
1. piriformis muscle
2. fibrous bands in proximity to the superior gluteal artery
3. hamstring muscles
4. gemelli-obturator complex
5. superior gluteal nerve entrapment
6. sciatic nerve entrapment
Once discogenic pathology has been ruled out with the NeuroCentric Approach, the most common cause of posterior gluteal pain is sciatic nerve and/orsuperior gluteal nerve entrapment. The piriformis muscle no longer should be considered as theonly mechanism for posterior gluteal pain. A thorough orthopedic examination of the superior gluteal nerve needs to be evaluated outside of the more common sciatic nerve entrapment, especially when patients are not responding to traditional treatment.
We discuss evaluation methods in NeuroCentric Approach coursework, but here let’s discuss anatomy.
The superior gluteal nerve originates from the ventral branches of lumbar and sacral plexus via the L4, L5 and S1 nerve roots. The nerve reliably emerged from the suprapiriform foramen on the superior edge of the piriformis muscle. The nerve travels in parallel with the piriformis muscle and divides into superior and inferior branches to supply several muscles of the hip.
The superior branch of the superior gluteal nerve tends to be the nerve that supplies the muscles of hip abduction such as the gluteus medius and the tensor fascia latae.
The inferior branch innervates the gluteus minimus, piriformis and tensor fascia latae.
Surgical anatomy literature (Kampa, 2007) divides the nerves of the hip into a figurative clock face to orient the surgeon to safe entry into the hip capsule. The anatomical reference point for the clock is the 6 o’clock position which is the inferior acetabular notch. There are deep nerve fibers that also supply sensory innervation to the superior portion to the hip capsule from 9 o’clock to 1 o’clock. This is an important piece to the puzzle in femoroacetabular impingement from the perspective of the NeuroCentric Approach (NCA)
The superior branch of the superior gluteal nerve tends to be the nerve that supplies the muscles of hip abduction such as the gluteus medius and the tensor fascia latae.
The inferior branch innervates the gluteus minimus, piriformis and tensor fascia latae.
Surgical anatomy literature (Kampa, 2007) divides the nerves of the hip into a figurative clock face to orient the surgeon to safe entry into the hip capsule. The anatomical reference point for the clock is the 6 o’clock position which is the inferior acetabular notch. There are deep nerve fibers that also supply sensory innervation to the superior portion to the hip capsule from 9 o’clock to 1 o’clock. This is an important piece to the puzzle in femoroacetabular impingement from the perspective of the NeuroCentric Approach (NCA)
In the NeuroCentric Approach the superior gluteal nerve innervating the piriformis is an important clinical pearl! In classic innervation charts the piriformis muscle is thought to be primarily innervated primarily by theS1 and S2 nerve roots.
Recent further investigation (Iwanaga, 2019) revealed that the innervation of the piriformis muscle includes several anatomical variations from spinal nerve roots and motor nerves of the peripheral nervous system. These include the ventral branches of the L5, S1, S2 nerve roots, inferior gluteal nerve and the superior gluteal nerve.
Recent further investigation (Iwanaga, 2019) revealed that the innervation of the piriformis muscle includes several anatomical variations from spinal nerve roots and motor nerves of the peripheral nervous system. These include the ventral branches of the L5, S1, S2 nerve roots, inferior gluteal nerve and the superior gluteal nerve.
The graph above shows that the superior gluteal nerve has an equal innervation in frequency as compared to the S1 and S2 nerve roots!
NeuroCentric Approach Clinical Pearl: “The number of nerves to the piriformis muscle ranged from one to six on each side (with a mean of 2.65), one on two sides (10%), two on seven sides (35%), three on nine sides (45%), four on one side (5%)”.
Important clinical considerations:
1) The DDX for neurogenic pain in the buttockshould consider superior gluteal nerve entrapment and not only sciatic nerve entrapment
2) Through the NeuroCentricApproach examination it’s possible to relieve entrapments utilizing a variety of manual methods (neurodynamics, nerve unloading exercises, transverse force technique)
3) All possibleinnervation patterns should be consideredto determine which major peripheral nerve has sustained damage, injury or entrapment. This exploration can be mechanical, physiological or functionally mediated.
Important clinical considerations:
1) The DDX for neurogenic pain in the buttockshould consider superior gluteal nerve entrapment and not only sciatic nerve entrapment
2) Through the NeuroCentricApproach examination it’s possible to relieve entrapments utilizing a variety of manual methods (neurodynamics, nerve unloading exercises, transverse force technique)
3) All possibleinnervation patterns should be consideredto determine which major peripheral nerve has sustained damage, injury or entrapment. This exploration can be mechanical, physiological or functionally mediated.
Spray Pattern 70-80%
Unlike traditional anatomical textbooks that depict a static, universal anatomical perspective, in clinical diagnosis and treatment,variability in nerve position must be considered.For the superior gluteal nerve, there are actually 2 different major branching fibers of the nerve, the transverse trunk pattern and the “spray” pattern.
Several authors (Stecco, 2012; Jacobs, 1989) found the spray nerve branching pattern to be present in 70-80% of cadavers. This pattern has the nerve entering the deep surface of the gluteus medius in a vertical pattern with several branches from 11 o’clock to 2 o’ clock in orientation after it exits the greater sciatic foramen.
Several authors (Stecco, 2012; Jacobs, 1989) found the spray nerve branching pattern to be present in 70-80% of cadavers. This pattern has the nerve entering the deep surface of the gluteus medius in a vertical pattern with several branches from 11 o’clock to 2 o’ clock in orientation after it exits the greater sciatic foramen.
The transverse trunk pattern has an occurrence of 20-30%.In these specimens, once the superior gluteal nerve travels out of the foreman it enters the deep surface of the gluteus medius muscle and continues parallel to the greater trochanter from posterior to anterior.
If a clinician is to be successful in treating the superior gluteal nerve, then orientation of branching patterns is vital to clinical effectiveness. Whether neurodynamic procedures, exercise or manual therapy approaches are used to release or desensitize the nerve, an understanding of anatomical variability improves outcomes.In NeuroCentric Approach coursework, we explore this from both a manual therapy and a functional exercise perspective.
If a clinician is to be successful in treating the superior gluteal nerve, then orientation of branching patterns is vital to clinical effectiveness. Whether neurodynamic procedures, exercise or manual therapy approaches are used to release or desensitize the nerve, an understanding of anatomical variability improves outcomes.In NeuroCentric Approach coursework, we explore this from both a manual therapy and a functional exercise perspective.
Transverse Branching Pattern 20-30%
Palpation: The Deep Gluteal Syndrome Compression Test
The deep gluteal compression test is an simple yet effective way to confirm the presence of DSG and sensitivity of the neurovascular structures as they exit the greater sciatic foramen. This depicted above test is a manual compression test into the foramen.
Recreation of pain with hip extended and 0 degrees of hip add/abduction.
The test is positive if pain is reduced or eliminated by bringing the hip into abduction (at least 20 degrees).
Deep Gluteal Syndrome Compression Test
Positive= Decreased Pain with Hip Abduction
References:
Martin HD, Reddy M, Gómez-Hoyos J. Deep gluteal syndrome. J Hip Preserv Surg. 2015;2(2):99‐107. doi:10.1093/jhps/hnv029
Kampa RJ, Prasthofer A, Lawrence-Watt DJ, Pattison RM. The internervous safe zone for incision of the capsule of the hip. A cadaver study. J Bone Joint Surg Br. 2007;89(7):971‐976. doi:10.1302/0301-620X.89B7.19053
Iwanaga J, Eid S, Simonds E, Schumacher M, Loukas M, Tubbs RS. The majority of piriformis muscles are innervated by the superior gluteal nerve. Clin Anat. 2019;32(2):282‐286. doi:10.1002/ca.23311
Stecco, C., Macchi, V., Baggio, L., Porzionato, A., Berizzi, A., Aldegheri, R., & De Caro, R. (2012). Anatomical and CT angiographic study of superior gluteal neurovascular pedicle: implications for hip surgery. Surgical and Radiologic Anatomy, 35(2), 107–113. doi:10.1007/s00276-012-1014-z
Jacobs LG, Buxton RA (1989) The course of the superior gluteal nerve in the lateral approach to the hip. J Bone Joint Surg Am 71:1239–1243
Martin HD, Reddy M, Gómez-Hoyos J. Deep gluteal syndrome. J Hip Preserv Surg. 2015;2(2):99‐107. doi:10.1093/jhps/hnv029
Kampa RJ, Prasthofer A, Lawrence-Watt DJ, Pattison RM. The internervous safe zone for incision of the capsule of the hip. A cadaver study. J Bone Joint Surg Br. 2007;89(7):971‐976. doi:10.1302/0301-620X.89B7.19053
Iwanaga J, Eid S, Simonds E, Schumacher M, Loukas M, Tubbs RS. The majority of piriformis muscles are innervated by the superior gluteal nerve. Clin Anat. 2019;32(2):282‐286. doi:10.1002/ca.23311
Stecco, C., Macchi, V., Baggio, L., Porzionato, A., Berizzi, A., Aldegheri, R., & De Caro, R. (2012). Anatomical and CT angiographic study of superior gluteal neurovascular pedicle: implications for hip surgery. Surgical and Radiologic Anatomy, 35(2), 107–113. doi:10.1007/s00276-012-1014-z
Jacobs LG, Buxton RA (1989) The course of the superior gluteal nerve in the lateral approach to the hip. J Bone Joint Surg Am 71:1239–1243
