U.S. flag

An official website of the United States government

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.

Cover of StatPearls

StatPearls [Internet].

Show details

Anatomy, Shoulder and Upper Limb, Hand Anatomical Snuff Box

; ; .

Author Information and Affiliations

Last Update: February 19, 2023.


The anatomical snuffbox is a surface anatomy feature described as a triangular depression on the dorsum of the hand at the base of the thumb. The anatomical snuffbox is prominently visible upon ulnar deviation of the wrist and extension and abduction of the thumb. Its name was derived from using the depression as a means of placement for the inhalation of powdered tobacco, otherwise known as dry snuff. It was first described in the medical literature in 1850.[1] However, the anatomical snuffbox was not introduced into anatomy textbooks until the early 1900s when it was described by Germain Cloquet and Marie Francois Bichat.[2]

Anatomically, the anatomical snuffbox is bordered medially by the tendons of the extensor pollicis longus and laterally by the tendons of the muscles named the extensor pollicis brevis and the abductor pollicis longus. The floor of the anatomical snuffbox is formed by the scaphoid bone and trapezium bone of the wrist, as well as the tendons of the muscle named the extensor carpi radialis longus and the muscle named the extensor carpi radialis brevis. Within the anatomical snuffbox, the base of the first metacarpal bone can be palpated distally, and the styloid process of the radius can be palpated proximally. Contained within the anatomical snuffbox are the radial artery, the superficial branches of the radial nerve, and the cephalic vein.[3]

Clinically, the anatomical snuffbox is of importance owing to the fact that the scaphoid bone can be palpated at its floor, and it is, therefore, an easily examinable place to assess for signs of scaphoid fracture following trauma, which, if missed, can lead to long-term pain and functional disability.

Structure and Function

The anatomical snuffbox is a broadly triangular superficial depression in the skin that emerges when the thumb is held in abduction and the wrist in ulnar deviation. The triangle's base lies parallel to the lateral border of the radial head, while the apex point to the first metacarpophalangeal joint.

When viewing the dorsum of the hand from above, the medial (ulnar) edge of the anatomical snuffbox is formed by the tendon of the extensor pollicus longus muscle, while the lateral (radial) edge is formed by the tendons of extensor pollicus brevis and abductor pollicus longus which run closely in parallel.

The extensor pollicus longus originates from approximately halfway up the ulna and inserts into the base of the distal phalanx of the thumb, allowing it to be the key extensor of the terminal phalanx. It is innervated by the posterior interosseous nerve.[4] The extensor pollicus brevis (EPB) and abductor pollicus longus (APL) both originate from the posterior aspect of the radius and ulna, although the former muscle is more closely related to the radius and interosseous membrane.[5] The APL inserts as two tendon slips: one at the base of the first metacarpal and the second at the trapezium. The EBP, in contrast, inserts as a thin tendon at the base of the proximal phalanx of the thumb. Both the APL and EBL are innervated by the posterior interosseous nerve, and indeed both act to extend the thumb at the carpometacarpal joint, and the EBP can additionally extend the thumb at the metacarpophalangeal joint.

The base of the anatomical snuffbox contains various bony landmarks. From proximal to distal, these are the radial styloid, the scaphoid bone, the trapezium, and the base of the thumb metacarpal, all of which are palpable on examination with the hand in ulnar deviation with the thumb extended.[6]

The anatomical snuffbox is merely a surface anatomy characteristic and functions in context with other anatomical structures. However, y knowing the boundaries and contents of the anatomical snuff box, a healthcare provider can generate a differential diagnosis when a patient complains of pain in the area. For example, tenderness to palpation in the anatomical snuffbox after a fall on an outstretched hand indicates a scaphoid fracture and would require further testing, including radiologic X-rays, to accurately make the definitive diagnosis. Knowledge of the contents of the anatomical snuffbox will also aid the healthcare provider in those patients with difficult vascular access because both the radial artery and the cephalic vein lie within this area.[7][3]

Blood Supply and Lymphatics

Although the anatomical snuffbox does not have its own blood supply, several vessels course through the boundaries of this surface anatomy feature. Both the cephalic vein and radial artery lie within the anatomical snuffbox. However, the radial artery branches are the most discussed in the practice of medicine due to their supply of the scaphoid bone. Direct branches from the radial artery supply 80% of the proximal scaphoid through intraosseous retrograde flow through the articular foramina, while the remainder is supplied via the volar scaphoid branches of the radial artery that enter at the distal pole. Avascular necrosis of the scaphoid bone commonly occurs due to the unique flow found in the anatomical snuffbox to the scaphoid bone.[8]


The superficial nerve branches of the radial nerve that reside within the anatomical snuffbox can be rolled over the tendon of the muscle named the extensor pollicis longus. The tendon of this muscle serves as the medial border of the anatomical snuffbox.[9] The superficial branch of the radial nerve is the terminal branch of the radial nerve, which originates from the posterior cord of the brachial plexus (from nerve roots C5-C8 and T1). The course of this nerve involves passing down through the upper limb, traversing between the long and medial head of the triceps before taking a spiral-like course around the back of the humerus and piercing the intermuscular septum approximately one-third of the distance down the forearm. It gives off the clinically important posterior interosseous nerve (C7, C8), which is the last motor branch of the radial nerve before it terminates as the slender superficial radial nerve, running within the anatomical snuffbox to supply the skin of the two and a half digits from the radial aspect of the hand, and an area over the dorsum of the hand also.[10]


The anatomical snuffbox is bordered medially by the tendons of the extensor pollicis longus and laterally by the tendons of the extensor pollicis brevis and the abductor pollicis longus. As described earlier, the extensor pollicus brevis and abductor pollicus longus act to extend the thumb, moving it in the lateral horizontal plane.[11][12] This action occurs mainly at the carpometacarpal joint for the abductor pollicus longus, whereas the extensor pollicus brevis acts both at this joint and the metacarpophalangeal joint. The floor of the anatomical snuffbox is partially formed by the tendons of the muscle named the extensor carpi radialis longus and the muscle named the extensor carpi radialis brevis.[13]

Physiologic Variants

Through anatomical research, multiple variations of the tendons of the anatomical snuffbox have been discovered. Both the extensor pollicis longus and the abductor pollicis longus have been shown to have numerous tendon slips and different areas of insertion. This is clinically significant because it may predispose an individual patient to the development of tendinopathy of either of these two muscles. Surgical management, if needed, would also be affected because of these numerous variations in tendon location.[14][13]

Through similar cadaveric research, multiple variations have been noted in the location of the cephalic vein and the radial artery. Clinically this is important because intravenous access can be obtained in the anatomical snuffbox, and inadvertent arterial puncture may cause a pseudo-aneurysm, arterial occlusion, or hematoma.[15]

Surgical Considerations

The superficial branch of the radial nerve is the third most common peripheral nerve injury and will cause an area of paresthesia over the dorsum of the first web space on the hand. Surgeons should be aware of their variable location within the anatomical snuffbox to avoid injury.[9]

The anatomical snuffbox can be used as a point of access for percutaneous arterial access for coronary intervention.[16][17] This approach has several advantages over the more commonly used radial artery approach; most importantly that if the angiography catheter occludes the artery completely, adequate collateral perfusion is strongly available from the radial artery still, and this will avoid ischemic injury of the hand. Furthermore, complications such as bleeding or spreading subcutaneous hematoma generally are managed locally within the anatomical snuffbox; that is, compression of the entire wrist is not necessary, in contrast to similar complications occurring following radial artery puncture, and this preserves movement of the wrist for the patient.[6] 

Finally, if the arterial access is not accessible in the anatomical snuffbox, or if, following successful cannulation, there is a procedural complication such as vasospasm or bleeding, the commonly used radial arterial access option remains available as a backup. Disadvantages of this approach include the fact that the caliber of the radial artery is relatively small in the anatomical snuffbox, but a cohort study demonstrated successful cannulation here with a 6 Fr catheter in 132 out of 150 patients, and the authors concluded that this approach is feasible and safe for both coronary angiography and percutaneous coronary intervention.[18]

Clinical Significance

The anatomical snuffbox is clinically significant when there is pain with palpation within its boundaries. Scaphoid fractures account for two-thirds of all carpal bone fractures and are commonly misdiagnosed. The most common form of injury is when a patient falls onto an outstretched hand when it is pronated and deviated in the ulnar plane. The hallmark of anatomic snuffbox tenderness is highly sensitive for scaphoid fractures but lacks specificity. Due to the lack of specificity, those with snuffbox tenderness should undergo radiographic studies of the wrist. Those with initial negative imaging can be managed with either a thumb spica short-armed splint or advanced imaging by MRI or CT to determine if a fracture exists. Given the unique blood flow to the scaphoid, fracture location is important in determining treatment options to prevent avascular necrosis of the bone.[19] 

The importance of correctly identifying scaphoid fractures is underlined by the fact that up to 32% of these fractures lead to non-union of the bone, which develops into osteoarthritis.[20] The effect of missing this clinically important fracture on the subsequent quality of life of the patient if non-union develops is potentially highly significant and detrimental. For patients who have a non-displaced or only minimally-displaced fracture of the scaphoid, systematic review and meta-analysis of relevant studies have suggested that there is no difference in long-term pain and disability outcomes between treating these with surgical or non-surgical methods.[21]

De Quervain tenosynovitis is a second clinically significant diagnosis relative to the anatomical snuffbox. De Quervain tenosynovitis is a stenosing tendinopathy that affects the first dorsal compartment, including the abductor pollicis longus and the muscle named the extensor pollicis brevis, both of which are lateral borders of the anatomical snuffbox. Diagnosis can be made based on a thorough history and physical examination. History may include repetitive hand motions in which repeated radio-ulnar deviation occurs. Patients will typically present with pain or swelling over the dorsal aspect of the wrist with associated aggravation of symptoms with the forced resistance of the thumb. Treatment typically includes conservative therapy with NSAIDs, corticosteroids, physical therapy, or splinting in a thumb spica splint. Surgery is reserved for refractory symptomology.[22]

Review Questions

Cutaneous innervation of the right upper extremity


Cutaneous innervation of the right upper extremity. Areas innervated by the radial nerve are colored in pink. Contributed by Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate (more...)

Anatomical Snuff Box and Ulnar Styloid Process


Anatomical Snuff Box and Ulnar Styloid Process. Shown here are the anatomical snuff box and ulnar styloid process. The boundaries of the anatomical snuff box are the tendons of the abductor pollicis longus and extensor pollicis brevis laterally (more...)



Hand Anatomical Snuffbox StatPearls Publishing Illustration



Scaphoid bone Contributed by Sunil Munakomi, MD


Sapundzhiev N, Werner JA. Nasal snuff: historical review and health related aspects. J Laryngol Otol. 2003 Sep;117(9):686-91. [PubMed: 14561353]
Seidenberg AB, Halperin EC, Goldstein AO. It's time to snuff out the "anatomical snuff box". Acad Med. 2015 Aug;90(8):1003-4. [PubMed: 26218360]
Berger RA. The anatomy of the scaphoid. Hand Clin. 2001 Nov;17(4):525-32. [PubMed: 11775465]
Strauch RJ, Strauch CB. Extensor pollicis brevis tendon can hyperextend thumb interphalangeal joint in absence of extensor pollicis longus: Case report and review of the literature. World J Orthop. 2016 Jul 18;7(7):448-51. [PMC free article: PMC4945512] [PubMed: 27458556]
Shigematsu S, Shimizu H, Beppu M, Hirata K. Anatomy of the extensor pollicis brevis associated with an extension mechanism of the thumb metacarpophalangeal joint. Hand Surg. 2014;19(2):171-9. [PubMed: 24875499]
Roh JH, Lee JH. Distal Radial Approach through the Anatomical Snuff Box for Coronary Angiography and Percutaneous Coronary Intervention. Korean Circ J. 2018 Dec;48(12):1131-1134. [PMC free article: PMC6221869] [PubMed: 30403016]
Sendher R, Ladd AL. The scaphoid. Orthop Clin North Am. 2013 Jan;44(1):107-20. [PubMed: 23174330]
Gelberman RH, Menon J. The vascularity of the scaphoid bone. J Hand Surg Am. 1980 Sep;5(5):508-13. [PubMed: 7430591]
Robson AJ, See MS, Ellis H. Applied anatomy of the superficial branch of the radial nerve. Clin Anat. 2008 Jan;21(1):38-45. [PubMed: 18092362]
Gurses IA, Coskun O, Gayretli O, Kale A, Ozturk A. The relationship of the superficial radial nerve and its branch to the thumb to the first extensor compartment. J Hand Surg Am. 2014 Mar;39(3):480-3. [PubMed: 24495622]
Öztürk K, Dursun A, Kastamoni Y, Albay S. Anatomical variations of the extensor tendons of the fetal thumb. Surg Radiol Anat. 2021 May;43(5):755-762. [PubMed: 33170332]
Sugiura S, Matsuura Y, Suzuki T, Nishikawa S, Mori C, Kuniyoshi K. Variant course of extensor pollicis brevis tendon in the third extensor compartment. Surg Radiol Anat. 2018 Mar;40(3):345-347. [PubMed: 29138875]
Adams JE, Habbu R. Tendinopathies of the Hand and Wrist. J Am Acad Orthop Surg. 2015 Dec;23(12):741-50. [PubMed: 26510626]
Thwin SS, Fazlin F, Than M. Multiple variations of the tendons of the anatomical snuffbox. Singapore Med J. 2014 Jan;55(1):37-40. [PMC free article: PMC4291910] [PubMed: 24452976]
Lirk P, Keller C, Colvin J, Colvin H, Rieder J, Maurer H, Moriggl B. Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study. Br J Anaesth. 2004 May;92(5):740-2. [PubMed: 15003983]
Pua U, Quek LHH. "Snuffbox" Distal Radial Access. J Vasc Interv Radiol. 2018 Jan;29(1):44. [PubMed: 29258662]
Kiemeneij F. Left distal transradial access in the anatomical snuffbox for coronary angiography (ldTRA) and interventions (ldTRI). EuroIntervention. 2017 Sep 20;13(7):851-857. [PubMed: 28506941]
Kim Y, Ahn Y, Kim I, Lee DH, Kim MC, Sim DS, Hong YJ, Kim JH, Jeong MH. Feasibility of Coronary Angiography and Percutaneous Coronary Intervention via Left Snuffbox Approach. Korean Circ J. 2018 Dec;48(12):1120-1130. [PMC free article: PMC6221867] [PubMed: 30088362]
Ko JH, Pet MA, Khouri JS, Hammert WC. Management of Scaphoid Fractures. Plast Reconstr Surg. 2017 Aug;140(2):333e-346e. [PubMed: 28746289]
Cohen A, Reijman M, Kraan GA, Mathijssen NMC, Koopmanschap MA, Verhaar JAN, Mol S, Colaris JW., SUSPECT study group. Clinically SUspected ScaPhoid fracturE: treatment with supportive bandage or CasT? 'Study protocol of a multicenter randomized controlled trial' (SUSPECT study). BMJ Open. 2020 Sep 29;10(9):e036998. [PMC free article: PMC7526317] [PubMed: 32994236]
Li H, Guo W, Guo S, Zhao S, Li R. Surgical versus nonsurgical treatment for scaphoid waist fracture with slight or no displacement: A meta-analysis and systematic review. Medicine (Baltimore). 2018 Nov;97(48):e13266. [PMC free article: PMC6283056] [PubMed: 30508914]
Ashurst JV, Turco DA, Lieb BE. Tenosynovitis caused by texting: an emerging disease. J Am Osteopath Assoc. 2010 May;110(5):294-6. [PubMed: 20538752]

Disclosure: Sasha Hallett declares no relevant financial relationships with ineligible companies.

Disclosure: Felix Jozsa declares no relevant financial relationships with ineligible companies.

Disclosure: John Ashurst declares no relevant financial relationships with ineligible companies.

Copyright © 2023, StatPearls Publishing LLC.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

Bookshelf ID: NBK482228PMID: 29489241


  • PubReader
  • Print View
  • Cite this Page

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Similar articles in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...