What are sharpeys fibres?
Sharpey’s fibres (bone fibres, or perforating fibres) are a matrix of connective tissue consisting of bundles of strong predominantly type 1 collagen fibres connecting periosteum to bone.
Sharpey’s fibres are also used to attach muscle to the periosteum of bone by merging with the fibrous periosteum and underlying bone as well. A good example is the attachment of the rotator cuff muscles to the blade of the scapula.
What is the structure of tendons?
They have a longitudinal arrangement of cells (mostly tenocytes) and fibres (collagen type 1 triple helix).
What are tenocytes?
Tenocytes are cells that are fibroblast like and form tenodons.
They synthesise extracellular matrix including assembly of early collagen fibres which are the basic units of a tendon.
What are the substructures of tendons and what are they covered by?
COLLAGEN BUNDLES covered by endotenon,
FASCICLES covered by paratenon,
TENDON covered by epitenon
Where is the blood supply for tendons?
Fine network of blood vessels in the paratendon
Give an example of where you might find a tendon sheath?
Flexor tendons in distal palm and fingers
How are tendons connected to the tendon sheath in distal palm and fingers?
By the vincula
What is the structure of tendon sheaths?
Tendon sheaths are tubular double-layered sacs lined with synovial membrane and containing synovial fluid. Tendon sheaths enclose many tendons, including the flexor tendons of the wrist and ankle where they perform the important function of keeping friction as low as possible, while faciliating movement of the joint.
What is the function of tendons?
They are flexible and are very strong in tension
What happens when tendons become immobile?
This reduces the water content and glycosaminoglycan concentration and strength
What are the types of tenon injury?
- enthesopathy - disorder involving the attachment of a tendon or a ligament to bone.
- traction apophysitis (osgood schlatters disease)
- avulsion (pulling or tearing away) ± bone fragment *
- tear - intrasubstance (rupture) *
- tear - musculotendinous junction
- laceration/ incision
- crush / ischaemia / attrition
Give an example of a degeneration disease of a tendon
Intrasubstance mucoid degeneration (cell substance is covnerted into glutinus substance like mucus)
What are the signs and symptoms of achilles intrasubstance mucoid degeneration?
May be swollen, painful, tender and may be asymptomatic
Give an example of a disease causing inflammation of a tendon
De quervain’s stenosing tenovangitis
Enthesiopathy (an example of a ligament would be plantar fasciitis)
What tendons are involved in De quervain’s stenosing tenovangitis?
Extensor pollicis brevis and abductor pollicis longus
They pass through the common tendon sheath at radial aspect of wrist.
What are the signs and symptoms of de quervains stenosing tenovangitis?
Swollen, tender, hot, red
Positive finklestein’s tets
Which part of the muscle is usually affected in enthesiopathy?
Usually the muscle insertion as opposed to the muscle origin
What is the difference between origin and insertion?
Origin - fixed attachment
Insertion - moves with contraction
Which parts of the knee are affected in traction apophysitis? (osgood schlatters disease)
insertion of patellar tendon into anterior tibial tuberosity
adolescent active boys
There is pulling on the insertion, but it does not cause any harm.
It is the painful inflammation of a bony outgrowth, especially in the area of active growth such as the end of a long bone.
Pulling or tearing away
Which part of the muscle is affected in avulsion?
What causes avulsion?
•Load exceeding failure strength while muscle contracting
What is the treatment for avulsion?
•Conservative - stack splint
–Fixation bone fragment
How does an intrasubstance rupture happen? e.g achilles
Load exceeds failure strength
What is the mechanism of rupture of an achilles tendon?
·pushing off with weight bearing forefoot whilst extending knee joint (53%) e.g. sprint starts or jumping movements
·unexpected dorsiflexion of ankle (17%) e.g. slipping into hole
·violent dorsiflexion of plantar flexed foot (10%) e.g. fall from height
What are the achilles tendon rupture tests?
Simmonds test - squeeze test
Altered angle of dangle
Palpable tender gap
Where is it common to have a musclotendinous tear?
•- e.g. medial head of gastrocnemius at musculotendinous junction with Achilles tendon
–“plantaris syndrome” (mis-called)
What is the treatment for a tendon rupture?
–Where ends can be opposed
- Mobilise (partial rupture) e.g. med lig knee
–Where healing will occur
- Not intraarticular
–High risk rerupture
–Ends cannot be opposed
Where is incision likely to occur to tendons?
•- e.g. esp. finger flexors (FDS & FDP) (flexor digitorum superficialis and felxor digitorum profundus)
–males > females
–repair surgically & early - beware old injuries!