Obturator Nerve

Innervation

• Sensory 
  • medial aspect of the thigh
  • articular branches to hip and knee joints
• Motoro
  • obturator externus
  • adductor longus
  • adductor magnus
  • adductor brevis
• gracilis

Course of Obturator Nerve

• Origin
  • obturator nerve comes from L2, L3, and L4
• Course
  • substance of psoas
    • the obturator decends through the substance of the psoas and exits medially near pelvic brim
  • behind common iliac vessels
    • passes behind common iliac vessels, lateral to the hypogastric vessels
  • anterior to obturator vessels
    • runs along lateral wall of lesser pelvis, anterior to the obturator vessels
  • enters obturator foramen
    • enters the superior aspect of the obturator foramen
    • it then enters the thigh through the obturator canal
• Terminal branches
  • anterior branch
    • innervates
      • adductor longus
      • gracilis
  • posterior branch
    • innervates
      • adductor magnus
      • adductor brevis
• these branches are separated by the obturator externus and adductor brevis

Clinical Conditions

• Obturator nerve block

Overview

The obturator nerve is a major peripheral nerve that arises from the lumbar plexus, specifically from the anterior divisions of the ventral rami of the second, third, and fourth lumbar spinal nerves (L2-L4). It plays a crucial role in innervating the muscles of the medial thigh and providing sensory information to the skin of the inner thigh.

Here are some key points about the obturator nerve:

1. Course: After its origin, the obturator nerve descends through the psoas muscle and then passes through the obturator foramen, a bony opening in the pelvis. It divides into two branches, the anterior and posterior branches, which enter the medial compartment of the thigh.
2. Motor function: The obturator nerve primarily innervates the muscles of the medial thigh. These muscles include the adductor longus, adductor brevis, adductor magnus (adductor portion), gracilis, and obturator externus. These muscles are responsible for adduction of the thigh, which involves pulling the leg toward the midline of the body.
3. Sensory function: The obturator nerve provides sensory innervation to the skin of the upper medial thigh. The specific distribution of sensory branches can vary, but generally, it covers the region from the groin to the knee, along the inner aspect of the thigh.
4. Clinical significance: Injury or dysfunction of the obturator nerve can result from various causes, including trauma, compression, or nerve entrapment. Symptoms of obturator nerve dysfunction may include weakness or paralysis of the adductor muscles, leading to difficulty with leg adduction and a characteristic gait disturbance. Sensory disturbances, such as numbness or tingling in the inner thigh, may also occur.
5. Diagnosis and treatment: Evaluation of obturator nerve dysfunction involves a comprehensive clinical examination, including assessment of muscle strength, reflexes, and sensory function. Nerve conduction studies and electromyography (EMG) may be performed to confirm the diagnosis and determine the location and severity of the nerve injury. Treatment depends on the underlying cause and may include conservative measures, such as rest, physical therapy, pain management, and addressing any underlying compression or entrapment. In severe cases or when conservative treatments fail, surgical intervention may be considered.

It’s important to note that this is a general overview and specific medical advice or information regarding an individual case should be obtained from a healthcare professional.

Studies

Numerous studies have been conducted on various aspects of the obturator nerve, including its anatomy, function, pathology, and treatment. Here are a few notable studies in the field:

1. “The anatomy and pathologic features of the obturator nerve” by Shoja et al. (2013): This study provides a detailed review of the anatomy and anatomical variations of the obturator nerve. It discusses the clinical relevance of these variations and highlights potential pitfalls during surgical procedures involving the nerve.
2. “Anatomical variations of the obturator nerve: implications for anterior total hip arthroplasty” by Luo et al. (2015): This study investigates the anatomical variations of the obturator nerve in relation to anterior total hip arthroplasty. It emphasizes the importance of understanding the nerve’s course and variations to minimize the risk of nerve injury during the surgical procedure.
3. “Obturator neuropathy: a comprehensive review of the literature” by David et al. (2018): This review article provides a comprehensive overview of obturator neuropathy, including its etiology, clinical presentation, diagnostic evaluation, and treatment options. It discusses both traumatic and non-traumatic causes of obturator neuropathy and summarizes the available evidence on conservative and surgical management approaches.
4. “Management of obturator nerve injuries: a systematic review” by Kluck et al. (2019): This systematic review evaluates the available literature on the management of obturator nerve injuries. It summarizes the outcomes of different treatment modalities, including conservative management, nerve decompression, and nerve grafting. The study aims to guide clinicians in making informed decisions regarding the optimal management strategy for obturator nerve injuries.

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