Shen Jin Cao (伸筋草) — TCM Club Moss for Sinew Contracture & Bi-Syndrome

At a Glance

• Herb: Shen Jin Cao
• Chinese name: 伸筋草 (Shēn Jīn Cǎo)
• Latin name: Lycopodii Herba
• Nature: Warm
• Taste: Acrid / Bitter
• Meridian: Liver / Spleen / Kidney
• Category: Herbs that Expel Wind-Dampness
• Introduction: Shen Jin Cao (Herba Lycopodii) is the dried whole plant of Lycopodium japonicum, a club moss distributed across southern and southwestern China and growing in forested hillsides. Its name — meaning ‘Extend Sinew Herb’ — directly reflects its primary clinical action: relaxing and extending contracted sinews and tendons stiffened by Wind-Cold-Damp obstruction. Recorded in the Ben Cao Shi Yi (8th century CE), this bitter, pungent, and warm herb unblocks channels while relaxing sinew tension, making it indispensable for joint contracture, post-stroke spasticity, and trauma. Lycopodine alkaloids and triterpenoids contribute to its skeletal muscle relaxant and anti-inflammatory effects in modern pharmacological studies.

Action

• Dispels Wind-Cold-Damp and unblocks the channels
• Relaxes sinews and relieves cramping, spasm, and contracture
• Activates Blood and reduces swelling from traumatic injury

Clinical Application

• Wind-Cold-Damp Bi-syndrome with sinew and joint stiffness, contracture, and restricted range of motion
• Post-stroke limb spasticity and sinew contracture
• Traumatic injury with swelling, bruising, and restricted movement
• Leg cramping and muscle spasm from Wind-Damp obstruction of channels

Precautions

• Dose: 3–12 g in decoction
• Contraindicated in pregnancy — pungent dispersing and Blood-activating properties may stimulate uterine contraction
• Avoid in patterns without Wind-Damp involvement — its dispersing nature may injure Qi in deficient patients
• Caution in patients with myasthenia gravis — lycopodine has anticholinesterase activity and may interact with neuromuscular conditions
• Not suitable for heat-type Bi-syndrome without cold component

Formula

• Combined with Mu Gua and Bai Shao for sinew cramping and spasm from Wind-Damp
• Combined with Ru Xiang, Mo Yao, and Hong Hua for traumatic injury with Blood stasis, swelling, and pain
• Combined with Du Huo, Wei Ling Xian, and Hai Feng Teng for Wind-Cold-Damp Bi-syndrome with joint restriction and contracture
• Combined with Gui Zhi and Ji Xue Teng for post-stroke limb spasticity

Combinations

• Lycopodium (伸筋草) + Speranskia Herb (透骨草) + Safflower (红花) → expel wind-damp, activate blood, relax sinews; joint stiffness and contracture
• Lycopodium (伸筋草) + Clematis Root (威灵仙) + Chinese Quince (木瓜) → expel wind-damp, relax sinews and unblock channels; wind-damp painful impediment with limb stiffness

Pharmacological Effects

• Anti-inflammatory; analgesic
  • alkaloids — inhibit pain pathways
• Antispasmodic
  • relaxes skeletal muscle
• Cholinesterase inhibitor
  • lycopodine — potential in Alzheimer’s research
• Antitumor
  • mild
• antibacterial; name literally means ‘stretch-tendon herb’ — clinically emphasized for sinew relaxation; often used in external washes and soaks for joint stiffness

Classic Description

• Ben Cao Shi Yi (《本草拾遗》): ‘Governs chronic wind impediment, cold pain in the feet and knees, skin insensibility, and weakness of strength.’
• Dian Nan Ben Cao (《滇南本草》): ‘Descends qi; disperses fullness and obstruction across the chest; dislodges accumulated food in the stomach; removes long-standing hard accumulation in the abdomen; disperses edema.’
• Ben Cao Gang Mu (《本草纲目》): ‘Lycopodium expels wind and scatters cold, eliminates dampness and reduces swelling, relaxes sinews and unblocks the collaterals; used for wind-cold-damp painful impediment, joint soreness and pain, skin numbness, and limb weakness.’