The common synovial sheath for the flexor tendons or the ulnar bursa is a

synovial sheath A synovial sheath is one of the two membranes of a tendon sheath which covers a tendon. The other membrane is the outer fibrous tendon sheath. The tendon invaginates the synovial sheath from one side so that the tendon is suspended from the membran ...

in the

carpal tunnel In the human body, the carpal tunnel or carpal canal is the passageway on the palmar side of the wrist that connects the forearm to the hand. The tunnel is bounded by the bones of the wrist and flexor retinaculum from connective tissue. Normall ...

of the human hand. It contains tendons of the

flexor digitorum superficialis Flexor digitorum superficialis (''flexor digitorum sublimis'') is an extrinsic flexor muscle of the fingers at the proximal interphalangeal joints. It is in the anterior compartment of the forearm. It is sometimes considered to be the deepest pa ...

and the

flexor digitorum profundus The flexor digitorum profundus is a muscle in the forearm of humans that flexes the fingers (also known as digits). It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm. Together t ...

, but not the

flexor pollicis longus The flexor pollicis longus (; FPL, Latin ''flexor'', bender; ''pollicis'', of the thumb; ''longus'', long) is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is uniqu ...

. The sheath which surrounds the flexor digitorum extends downward about halfway along the

metacarpal bones In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ...

, where it ends in blind diverticula around the tendons to the

index Index (or its plural form indices) may refer to: Arts, entertainment, and media Fictional entities * Index (''A Certain Magical Index''), a character in the light novel series ''A Certain Magical Index'' * The Index, an item on a Halo megastru ...

, middle, and

ring finger The ring finger, third finger, fourth finger, leech finger, or annulary is the fourth digit of the human hand, located between the middle finger and the little finger. Sometimes the term ring finger only refers to the fourth digit of a left-han ...

s. It is prolonged on the tendons to the little finger and usually communicates with the mucous sheath of these tendons.

References

File:Slide11AAAA.JPG, flexor tendon sinovial sheath of hand File:Slide5BBBB.JPG, flexor tendon sinovial sheath of hand File:Slide8HHHH.JPG, flexor tendon sinovial sheath of hand

External links

* https://web.archive.org/web/20070814124446/http://moon.ouhsc.edu/dthompso/namics/labs/wrist2.htm Upper limb anatomy {{musculoskeletal-stub