Tendon sheath

sheath (shēth) a tubular case or envelope.

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arachnoid sheath  the continuation of the arachnoidea mater around the optic nerve, forming part of its internal sheath.

carotid sheath  a portion of the cervical fascia enclosing the carotid artery, the internal jugular vein, and the vagus nerve.

crural sheath  femoral s.

dentinal sheath  the layer of tissue forming the wall of a dentinal tubule.

dural sheath  the external investment of the optic nerve.

femoral sheath  the investing fascia of the proximal portion of the femoral vessels.

sheath of Henle  endoneurium.

Hertwig sheath  root s. (1).

sheath of Key and Retzius  endoneurium.

lamellar sheath  the perineurium.

Mauthner's sheath  axolemma.

medullary sheath , myelin sheath the sheath surrounding the axon of myelinated nerve cells, consisting of concentric layers of myelin formed in the peripheral nervous system by the plasma membrane of Schwann cells, and in the central nervous system by oligodendrocytes. It is interrupted at intervals along the length of the axon by gaps known as nodes of Ranvier. Myelin is an electrical insulator that serves to speed the conduction of nerve impulses.

pial sheath  the continuation of the pia mater around the optic nerve, forming part of its internal sheath.

root sheath 

1. an investment of epithelial cells around the unerupted tooth and inside the dental follicle.

2. the epithelial portion of a hair follicle.

sheath of Schwann  neurilemma.

synovial sheath  synovial membrane lining the cavity of a bone through which a tendon moves.

tendon sheath  epitendineum.

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Tendon sheath

A membrane covering a tendon.

Mentioned in: Trigger Finger

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tendon

a sheet, cord or band of strong white fibrous tissue that connects a muscle to a bone or other structure. When the muscle contracts, or shortens, it pulls on the tendon. Tendons serve to convey an action to a remote site, change the direction of pull and focus the force. Sheetlike tendons (aponeuroses) serve to support and squeeze, cordlike ones to act on joints. See also cunean tendon.

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tendon aponeuroses

see aponeurosis.

bowed tendon

chronic tendinitis of the superficial flexor tendons, usually of the front limbs, of a horse. The horse is lame or inclined to lameness, the tendon is thickened and is visibly enlarged. It may be painful on palpation in the early, acute stages.

calcaneal tendon

see achilles tendon.

tendon cartilaginous metaplasia

focal metaplasia with the formation of cartilage in tendons causes no apparent harm and is considered to be normal.

common calcanean tendon

see achilles tendon.

congenital tendon contracture

an inherited contracture of multiple tendons is identified in cattle. The joints are fixed in extension or flexion and cause serious dystocia. See also akabane virus disease.

Congenital contracture of flexor tendons. By permission from Blowey RW, Weaver AD, Diseases and Disorders of Cattle, Mosby, 1997

contracted t's

see tendon contracture (below).

tendon contracture

permanent contraction of a tendon caused by chronic tendinitis. Most commonly of the flexor tendons of the digit in the horse. The action of the affected limb is restricted and the limb is not fully extended at rest causing the animal to stand up on its toe. Called also contracted tendons.

flexor t's

tendons of the superficial and deep flexor muscles of the digit. Commonly strained, lacerated and separated in the racing horse.

tendon graft

done in horses with badly torn or ruptured flexor tendons. Autologous grafts are taken from the lateral digital extensor tendon.

hamstring tendon

see hamstring.

tendon implants

see carbon fiber implants.

internal biceps tendon

a core of fibrous tissue within the biceps muscle of horses which serves a significant role in the stay apparatus.

interosseous tendon

suspensory ligament (1).

tendon luxation

slipping of the superficial flexor tendon of the hindlimb of the horse off the tuber calcis, usually in the medial direction; also occurs rarely in dogs and ostriches. See also perosis.

tendon osseous metaplasia

a pathological abnormality and usually attended by abnormality of movement. See also tendon ossification (below).

tendon ossification

occurs extensively in gallinaceous birds in the tendons of the legs and feet, the wings and the epaxial musculature. Although the ossification may be extensive the birds are normal and the reasons for the changes are unknown.

prepubic tendon

the tendon of insertion of the two abdominal recti muscles on to the pubis.

tendon sheath

a fluid-filled sleeve that resembles a synovial bursa wrapped around the tendon so as to form a continuous sheath, except for the mesotendon.

tendon splitting

performed by slitting the superficial flexor tendon (or the suspensory ligament) along its long axis and from lateral to medial sides as a treatment for tendinitis. The objective is to stimulate vascularization and hasten repair.

tendon sprain

see sprain.

sprained tendon

see tendon strain (below).

tendon strain

the injury caused to flexor tendons in the horse during racing. Most commonly affected is the superficial flexor tendon in the front limb. See also bowed tendon (above). Called also sprained tendon.

symphysial tendon

a vertical median sheet which hangs from the pubic symphysis and provides an origin for the medial thigh muscles.