Nerve Entrapment Syndromes
There are a variety of nerves that can become entrapped or compressed around the pelvis causing acute, subacute or chronic pain. Many of these syndromes are caused by trauma (surgical, pregnancy or sports) and / or exercise-related injuries. The two most common nerve entrapment syndromes causing pelvic pain are piriformis syndrome and pudendal nerve entrapment. Lumbar plexus entrapment syndromes are not as common and thus will be briefly discussed.
Nerve entrapment syndromes account for only a small portion of conditions responsible for causing pelvic pain, nonetheless it is important to identity these syndromes and their subsequent signs and symptoms.
Nerve entrapment syndromes account for only a small portion of conditions responsible for causing pelvic pain, nonetheless it is important to identity these syndromes and their subsequent signs and symptoms.
Piriformis SYndrome
The piriformis muscle originates on the sacrum and inserts on the superior aspect of the greater trochanter. In the majority of the population, the sciatic nerve travels below the piriformis muscle which makes it prone to irritation. In a small portion of the population (12%) the fibular portion of the sciatic nerve passes through the piriformis and thus contraction of the muscle can produce radicular symptoms. Symptoms include deep buttock pain, numbness and general discomfort along with radiating pain down the lower extremity. Physical therapy treatment consists of stretching and rest. Additionally, NSAIDs may be prescribed for pain management. Below you will find the six cardinal signs by Robinson who is credited with the introduction of piriformis syndrome.
Six cardinal signs:
Six cardinal signs:
- A history or trauma of the sacroiliac and gluteal regions
- Pain in the region of the sacroiliac joint, greater sciatic notch, and piriformis muscle, extending down the lower limb and causing difficulty in walking
- Acute exacerbation of the symptoms by lifting or stooping
- A palpable, sausage-shaped mass over the piriformis muscle, during an exacerbation of symptoms which is tender to the touch
- Positive straight leg raise test
- Gluteal atrophy
Pudendal Nerve Entrapment
Pudendal nerve entrapment is characterized by entrapment of the pudendal nerve in Alcock's canal. The nerve arises from the ventral rami of S2, S3, and S4 passing through the sciatic notch and then dives deep into the perineum. Pain occurs at the base of the penis, perineum, anus, and labia.
Due to the location of this nerve, direct injuries are rare. Damage to this structure is usually caused by deep buttock injections, prolonged childbirth, surgical manipulation, pelvic fractures, and exercise-related injuries. The pudendal nerve is often entrapped in cyclists who in engage in prolong riding and could result in sensory loss or pudendal neuralgia.
If pudental nerve entrapment is suspected, the patient or client should be referred to a gynecologist or urologist for further testing.
Due to the location of this nerve, direct injuries are rare. Damage to this structure is usually caused by deep buttock injections, prolonged childbirth, surgical manipulation, pelvic fractures, and exercise-related injuries. The pudendal nerve is often entrapped in cyclists who in engage in prolong riding and could result in sensory loss or pudendal neuralgia.
If pudental nerve entrapment is suspected, the patient or client should be referred to a gynecologist or urologist for further testing.
Lumbar Plexus entrapment syndromes
Nerves that are commonly entrapped within the lumbar plexus include: lateral femoral cutaneous, obturator, iliohypogastric, ilioinguinal, and the genitofemoral nerve.These nerves can become entrapped or compressed anatomically anywhere along their route.
- Meralgia Paresthetica – Characterized by compression of the lateral femoral cutaneous nerve which travels under the inguinal ligament and exits the pelvis near the greater trochanter. Entrapment causes burning and tingling on the anterior and lateral aspects of the femur.
- Obturator Nerve Entrapment – The obturator nerve arises from the ventral rami of L2 - L4 and descends through the psoas muscle. The nerve continues to descend through the obturator tunnel where it divides into an anterior and posterior branch. Pain typically has an insidious onset and is localized to the adductor origin at the pubic bone.
- Iliohypogastric Nerve Entrapment - The iliohypogastric nerve arises from the primary ventral rami of L1 and L2. The nerve passes through the psoas muscle, travels behind the kidney, runs through the muscles of the abdominal wall and finally divides into the lateral and anterior cutaneous branches near the anterior superior iliac spine.
- Ilioinguinal Nerve Entrapment - The ilioinguinal nerve arises from the ventral rami of L1 and L2. The nerve travels through the psoas muscle and follows a similar route as the iliohypogastric nerve. The nerve enters the inguinal canal and further divides into its terminal branches that supplies the skin over the inguinal ligament, upper medial thigh, base of the penis and upper portion of the scrotum in men, and the labia in women. Signs and symptoms include: pain occurring in the inguinal region radiating to the genitals (usually the right side), sensory abnormalities, and tenderness to palpation medially and below the ASIS.
- Genitofemoral Nerve Entrapment - The genitofemoral nerve arises from the ventral rami of the L1 and L2 spinal nerve roots. The nerve descends behind the peritoneum and divides at the inguinal ligament into the genital and femoral branches.
Diagnosis
Clinical diagnosis is made when there are signs of motor weakness, sensory loss and / or changes in deep tendon reflexes. However diagnosis of nerve entrapment around the pelvis is quite challenging because the cutaneous sensory dermatomes overlap and many of the nerves in the pelvis do not have motor innervation making it difficult to test.
If a nerve entrapment is suspected in the pelvic region, patients should be referred to a physician to have neurophysiological tests conducted.
If a nerve entrapment is suspected in the pelvic region, patients should be referred to a physician to have neurophysiological tests conducted.
References
Dutton M. Orthopaedic Examination, Evaluation, and Intervention. 2 ed: McGraw-Hill, Medical Publishing Division; 2008.
Hillman S, ATC P. Core Concepts in Athletic Training and Therapy: Human Kinetics, Inc.; 2012.
Robinson DR. Pyriformis syndrome in relation to sciatic pain. Am J Surg. 1947;73(3):355-358.
Labat JJ, Riant T, Robert R, Amarenco G, Lefaucheur JP, Rigaud J. Diagnostic criteria for pudendal neuralgia by pudendal nerve entrapment (Nantes criteria). Neurourol Urodyn. 2008;27(4):306-310.
Rassner L. Lumbar plexus nerve entrapment syndromes as a cause of groin pain in athletes. Curr Sports Med Rep. 2011;10(2):115-120.
McCrory P, Bell S. Nerve entrapment syndromes as a cause of pain in the hip, groin and buttock. Sports Med. 1999;27(4):261-274.
Bradshaw C, McCrory P, Bell S, Brukner P. Obturator nerve entrapment. A cause of groin pain in athletes. Am J Sports Med. 1997;25(3):402-408.
Images
http://www.thehealthybackbl...2/05/piriformis.1-jpg13.jpg
http://www.ajronline.org/content/181/2/561/F1.large.jpg
http://www.bartleby.com/107/Images/small/image824.jpg
Hillman S, ATC P. Core Concepts in Athletic Training and Therapy: Human Kinetics, Inc.; 2012.
Robinson DR. Pyriformis syndrome in relation to sciatic pain. Am J Surg. 1947;73(3):355-358.
Labat JJ, Riant T, Robert R, Amarenco G, Lefaucheur JP, Rigaud J. Diagnostic criteria for pudendal neuralgia by pudendal nerve entrapment (Nantes criteria). Neurourol Urodyn. 2008;27(4):306-310.
Rassner L. Lumbar plexus nerve entrapment syndromes as a cause of groin pain in athletes. Curr Sports Med Rep. 2011;10(2):115-120.
McCrory P, Bell S. Nerve entrapment syndromes as a cause of pain in the hip, groin and buttock. Sports Med. 1999;27(4):261-274.
Bradshaw C, McCrory P, Bell S, Brukner P. Obturator nerve entrapment. A cause of groin pain in athletes. Am J Sports Med. 1997;25(3):402-408.
Images
http://www.thehealthybackbl...2/05/piriformis.1-jpg13.jpg
http://www.ajronline.org/content/181/2/561/F1.large.jpg
http://www.bartleby.com/107/Images/small/image824.jpg