The sympathetic innervation of the lower limb is originated from the lower 3 thoracic and upper 2 lumbar (T10-L2) sections of the spinal cord.

The preganglionic fibres originating from the lateral horn cells pass out via ventral roots. Afterward they pass down in the sympathetic chain to relay in the lumbar and upper 2 or 3 sacral ganglia.

The postganglionic fibres originating from the lumbar ganglia go through the femoral nerve to furnish the femoral artery and its branches.

The postganglionic fibres originating from the sacral ganglia (S2S3) go through the tibial nerve to provide the popliteal artery and its branches.

The sympathetic stimulation causes dilatation of the blood vessels supplying skeletal muscles. But, the sympathetic fibres are vasomotor, sudomotor, and pilomotor to the skin.

The lower limbs don’t have parasympathetic innervation.

Clinical Significance

Buerger’s disease: It’s an obliterative disorder of the lower limb arteries distal to the knee. It usually takes place in young male smokers. Medically, it presents as intermittent claudication, digital ischaemia, and decrease of the ankle pulses. The advancing ischaemia of digits may eventually necessitate amputation of the foot. The treatment contains quitting smoking and sympathectomy.

The sympathetic denervation of the lower limb is accomplished by removing 2nd, third, and fourth lumbar ganglia with the intermediate chain (lumbar sympathectomy). It’s important to notice that the very first lumbar ganglion is maintained because it controls the internal urethral sphincter. Its inadvertent removal contributes to dry coitus.