SI-08 (Xiao Hai) Small Sea

What does SI-08 Xiao Hai do?

SI-08 is the He-Sea and Earth point of the Small Intestine channel — and because the Small Intestine is a yang FIRE channel, Earth is Fire’s child, which makes SI-08 the channel’s SEDATION point. That is the classification a reader should carry away: when the classical texts call for draining excess or heat from this channel, the five-shu system nominates SI-08.

• Clears heat and disperses swelling — the sedation function applied along the channel
• Calms the spirit — the Small Intestine’s paired relationship with the Heart
• Activates the channel and alleviates pain — the local and channel action, for the elbow, arm, shoulder and neck

The Small Intestine five-shu roles, derived from this site’s own element records: SI-01 Shao Ze is Metal, SI-02 Qian Gu is Water, SI-03 Hou Xi is Wood, SI-05 Yang Gu is Fire, SI-08 is Earth. The Small Intestine is yang Fire, so:

• Tonification (mother) point — SI-03 Hou Xi (Wood, the mother of Fire)
• Sedation (child) point — SI-08 Xiao Hai (Earth, the child of Fire) — this point
• Horary point — SI-05 Yang Gu (Fire on a Fire channel)
• Controlling-element point — SI-02 Qian Gu (Water, which controls Fire) — none of the three

That matches the record already written for SI-02, which derived the same set independently. Note also that on yang channels the Yuan-Source point is separate from the Shu-Stream: SI-04 Wan Gu holds the Yuan classification here, not SI-03.

Source: Sacred Lotus sources & references (channel, element and action records; the full Small Intestine five-shu series and SI-04's Yuan classification queried from our own data and checked against the SI-02 record), cross-referenced against multiple online sources.

What is SI-08 Xiao Hai used for?

SI-08 is used for pain along its own channel — elbow, arm, shoulder and neck — and for headache, cheek swelling and epilepsy. Our own indication record is reproduced here in full.

• Headache
• Swelling of the cheek
• Pain in the nape of the neck
• Pain in the shoulder, arm and elbow
• Epilepsy

Most of that list is the channel’s course. The Small Intestine channel runs from the little finger along the back of the forearm, past the elbow, across the shoulder blade and up the side of the neck to the ear and cheek. Elbow, shoulder, nape and cheek are simply where it goes. The epilepsy and spirit-calming indications come from the channel’s pairing with the Heart.

How it is combined. With SI-03 Hou Xi, the channel’s tonification point and the Confluent point of the Du Mai, for neck and spine complaints — the two form a supplement-and-drain pair on one channel. With SI-11 Tian Zong and SI-12 Bing Feng on the shoulder blade for the scapular region. With LI-11 Qu Chi, the He-Sea point of the neighbouring yang channel at the other side of the same elbow. All are held here.

Source: Sacred Lotus sources & references (indication record; SI-03, SI-11, SI-12 and LI-11 classifications queried from our own data), cross-referenced against multiple online sources.

Where is SI-08 Xiao Hai located?

SI-08 is at the inner side of the elbow, in the groove between the tip of the olecranon and the bony bump of the medial epicondyle — the hollow most people know as the “funny bone”. That is not a loose comparison: it is the ulnar nerve’s groove, and the sensation it produces when struck is the reason the location is so recognisable.

• Between the olecranon and the medial epicondyle, in the ulnar groove
• Easiest to find with the elbow flexed, which opens the groove
• HT-03 Shao Hai lies at the same elbow but in front of the medial epicondyle — a different position entirely

The distinction from HT-03 is the important one, and it corrects a common assumption. The ulnar nerve runs behind the medial epicondyle, so SI-08 is the ulnar-nerve point — not HT-03, which sits in front of it. Our own HT-03 record makes exactly this correction and names SI-08 as the point the nerve actually concerns. Anyone attaching an ulnar-nerve caution to the Heart-channel elbow point has the wrong side of the bone.

On the name. “Xiao Hai” means Small Sea — xiao from Small Intestine, hai (sea) marking a He-Sea point, where the channel’s qi is described as entering deeply like a river reaching the sea. The name states the classification. Note it is easily confused in romanisation with HT-03 Shao Hai (Lesser Sea) at the same elbow — different character, different channel, different side of the epicondyle.

Source: Sacred Lotus sources & references (location and translation records, retained unchanged; HT-03's position and its ulnar-nerve correction queried from our own data).

• A Manual of Acupuncture (p. 239): In the depression between the tip of the olecranon process of the ulna and the tip of the medial epicondyle of the humerus.
• Chinese Acupuncture and Moxibustion (p. 169): When the elbow is flexed, the point is located in the depression between the olecranon and the ulna and the medial epicondyle of the humerus.

How is SI-08 Xiao Hai needled?

The standard texts record perpendicular insertion to roughly 0.3–0.5 inch, with moxibustion applicable. What follows is a neutral record of what the reference literature documents, not instruction for a reader.

• Angle and depth as recorded: perpendicular, 0.3–0.5 inch — shallow, and the recorded depth reflects how little soft tissue lies in the groove.
• Moxibustion: recorded as applicable.
• Regional anatomy: the ulnar nerve lies in the groove behind the medial epicondyle, directly at this point, with the superior ulnar collateral vessels alongside it. The nerve is superficial here — covered by little more than skin and fascia — which is why striking it produces the familiar electric sensation.

Hazard, stated proportionately and accurately. There is no body cavity beneath the elbow, so this is not a point with catastrophic potential. But it is the one elbow point where the ulnar nerve genuinely lies in the needle’s path, and a reader should know that the sensation of striking it is a nerve contact rather than a therapeutic phenomenon. Our record for HT-03 cites a bee-venom ulnar-injury case as regional rather than attributing it to that point — and on the anatomy, SI-08 is the point that sits over the nerve. No case report naming SI-08 as the site of an injury was located, and none is asserted here.

What is not claimed. No study measuring a safe depth at SI-08 could be located, and none is borrowed. The measured safe-depth work in this library covers thoracic, lumbar, gluteal, orbital and neck points; none describes the elbow.

Source: Sacred Lotus sources & references (needling record, retained unchanged; HT-03's ulnar-nerve finding queried from our own data), cross-referenced against multiple online sources; regional anatomy from standard anatomical description.

Is there research on SI-08, and what should a reader know?

No trial isolates SI-08. Where the point appears it is one component of a protocol for elbow, shoulder or neck pain, and a study that includes a point in a protocol is not evidence about that point.

The most useful thing this page can tell a reader is anatomical, not clinical. SI-08 sits in the ulnar groove; HT-03 sits in front of the medial epicondyle. Those are a couple of centimetres apart and belong to different channels with different classifications — SI-08 is a sedation point on a yang Fire channel, HT-03 is a controlling-element point on a yin Fire channel. A prescription naming one is not interchangeable with the other, and the ulnar-nerve consideration belongs to this point.

A romanisation caution. Xiao Hai (SI-08) and Shao Hai (HT-03) differ by one vowel in transliteration and sit at the same elbow. This library has documented six outright pinyin collisions between points — Zi Gong, Shen Que/Shen Men, Da Zhu, Fu Tu, Ju Liao and Zhong Zhu — and this near-collision is worth the same care. Confirm the code, not the romanised name.

What is reliable here. SI-08’s classification is firm and checkable: He-Sea and Earth point, and therefore the sedation point of a yang Fire channel. That derivation agrees with the SI-02 record written independently earlier in this library — sixteen channels have now been worked out from the element relationships, and every record agrees.

Source: Sacred Lotus sources & references (classification and indication records; HT-03's position and the documented pinyin collisions queried from our own data).