Accessory obturator nerve

Accessory Obturator Nerve

The accessory obturator nerve is a nerve in the human body that is present in approximately 10% of the population. It is considered an anatomical variant and is not found in all individuals. This nerve is part of the lumbar plexus, which is a network of nerve fibers that supplies the lower limb and pelvic region.

Anatomy

The accessory obturator nerve arises from the ventral divisions of the third and fourth lumbar nerves (L3 and L4). It is a branch of the lumbar plexus, which is formed by the anterior rami of the first four lumbar nerves (L1-L4) and contributions from the subcostal nerve (T12).

In cases where the accessory obturator nerve is present, it descends along the medial border of the psoas major muscle. It then passes over the superior pubic ramus, near the pubic symphysis, and enters the thigh.

Function

The accessory obturator nerve primarily innervates the pectineus muscle, which is located in the upper thigh. The pectineus muscle is responsible for adducting and flexing the thigh at the hip joint. In some individuals, the accessory obturator nerve may also provide sensory innervation to the hip joint and the skin over the medial aspect of the thigh.

Clinical Significance

The presence of the accessory obturator nerve can have clinical implications, particularly in surgical procedures involving the pelvis and hip. Surgeons must be aware of this anatomical variant to avoid inadvertent nerve damage during operations such as hip replacement or pelvic surgeries.

In some cases, the accessory obturator nerve may be involved in entrapment neuropathies, leading to pain or sensory disturbances in its area of distribution. However, such occurrences are rare due to the infrequent presence of the nerve.

Related Pages

• Lumbar plexus
• Obturator nerve
• Pectineus muscle
• Psoas major

Gallery

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  Diagram of the lumbar plexus with the accessory obturator nerve.
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  The course of the accessory obturator nerve in relation to the psoas major muscle.