Flexor Digitorum Superficialis Tendon


  • At the proximal interphalangeal joints, the flexor digitorum superficialis bends the middle phalanges of the medial four fingers. 
  • Additionally, it flexes the wrist joint and metacarpophalangeal joints' proximal phalanges. 
  • Each finger it supports can be independently flexed by the flexor digitorum superficialis.

Trigger Finger

  • Thickened flexor tendon in distal palm
  • Abnormal gliding and locking of Tendon within Sheath
  • Tendon caught at edge of first annular pulley
  • Catching during active flexion-extension
  • Stiff, tender, palpable nodule
  • Associated conditions RA, Gout

Diagnosis of Trigger Finger

  • No Lab tests, but may need to rule out associated conditions (HgbA1c), fasting blood glucose, RF
  • Xray rarely indicated and performed only if abnormal pathology exists (loose bodies in MCP joint, OA spurs on metacarpal head, evulsion injury of collateral ligament)

Locating the Flexor Superficialis Tendon


  • Steroid injection (first line). CPT 20550 76942
  • Less commonly performed- Custom made splint (holds MCP at 10-15 Degrees fo flexion leaving the PIP and DIP joints free 
  • Surgery if fails 2 injections
  • Surgical release of A1 pulley
  • Reference https://emedicine.medscape.com/article/1244693-overview?src=ppc_google_rlsa-lapsed-traf_mscp_emed_md_us&gclid=CjwKCAjwzdLrBRBiEiwAEHrAYsXA8BM-yy2xIcE0C52BTqbyT-Qy0DVFuWBBJwMhEhxNliaj3V-clBoCMf0QAvD_BwE

Trigger Finger

Trigger Finger

  • 25G 1.5 inch needle
  • Injectate 10mg-20mg Depomedrol with 1-2 ml Bupivicaine 0.25%, Total Volume 1-3ml
  • Feel Tendon Sheeth get Distended with injection 
  • Out of plane approach may be necessary but use caution to avoid tendon rupture

DeQuervaine’s Tendosynovitis

Thickening of and accumulation of mucopolysaccharide in the sheath of

  • Abductor Pollicis Longus Tendon
  • Extensor Pollicis Brevis Tendon

The  Extensor Retinaculum is a fibrous band attached to the radius and prevents bowstringing of the extensor tendons off the dorsum of wrist


  • Pain near the base of the thumb
  • Swelling near the base of the thumb
  • Difficulty moving the thumb and wrist when grasping or pinching during activities
  • A "sticking" or "stop-and-go" sensation in your thumb when moving it


Positive Finklestein’s Test: the examiner grasps the thumb and ulnar deviates the hand sharply.  if sharp pain occurs along the distal radius (top of forearm, close to wrist; see image), de Quervain's tenosynovitis is likely.

Eichhoff's test: the Eichhoff's test is typically described as the examiner grasping and ulnar deviating the hand when the person has their thumb held within their fist. If sharp pain occurs along the distal radius, De Quervain's tenosynovitis is suspected but more likely to produce false positive

DeQuervaine’s Tenosynovitis

Risk Factors

  • Repetitive movements
  • Pregnancy
  • Trauma
  • Rheumatic Disease

Differential Diagnosis

  • OA of first CMC joint
  • Ganglia
  • Warteberg’s Syndrome
  • Infectious Tenosynovitis

Wartenberg’s Syndrome: entrapment and mononeuropathy of the superficial branch of the radial nerve

Presents as a numbness, tingling, and weakness of the posterior aspect of the thumb.


  • Immobilizing Splint
  • Physical therapy, OT, TENS
  • Steroid Injection 
  • Surgery (risk to radial sensory nerve)

Stenosis tenosynovitis

  • Scan the radial aspect of the wrist.  
  • Extensor pollicis brevis and abductor pollis longus tendons are both involved because they share a common tendon sheath. 
  • Caused by overuse movements that require repetitive extension and abduction of the thumb. 
  • Superficial Injection
  • Skin atrophy and hypopigmentation  may occur with steroids

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  • Esmaeilnejad-Ganji SM, Baghianimoghadam B. Flexor Digitorum Superficialis and Flexor Digitorum Profundus with separated sheaths: a new normal variation in human. Colomb Med (Cali). 2015 Dec 30;46(4):199-201. PMID: 26848202; PMCID: PMC4732511.
  • Okafor L, Varacallo M. Anatomy, Shoulder and Upper Limb, Hand Flexor Digitorum Superficialis Muscle. [Updated 2021 Oct 21]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539723/
  • Caetano EB, Sabongi Neto JJ, Ribas LAA, Milanello EV. Accessory muscle of the flexor digitorum superficialis and its clinical implications. Rev Bras Ortop. 2017 Oct 21;52(6):731-734. doi: 10.1016/j.rboe.2017.10.004. PMID: 29234659; PMCID: PMC5720854.


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