Skeletal Muscle-Tendon Linkage

This figure provides a light microscopic image of the linkage between skeletal muscle fbers 1 and tendon fibers 2 . The muscle fibers only appear to continue in the collagen fiber bundles of tendons and aponeuroses. In reality,  the connection is made between the fine fiber matrix around the sarcolemma and the loose connective tissue in the immediate vicinity of the muscle fibers. There is no true continuity between contractile myofibrils and collagen fibrils. Individual tendon fibers finally merge in an acute angle to form tendons and aponeuroses.

1 Striated muscle fiber s

2 Collagen fiber s of the tendon

3 Collagenous connective tissue

Stain: azan; magnification: × 500

Skeletal Muscle-Tendon Linkage

Finger-like processes of the muscle fibers fan out and establish the link be-tween skeletal muscle and tendon. The myofibrils extend into the spaces between these processes, slide over the elongate d actin filaments up to the blind ends of the processes and end at the inner plasmalemma. This part of the plasmalemma is condense d to half-desmosomes. Fibrocytes in the tendon tissue (= tendon cells) 2 send out numerous cytoplasmic processes. These attach to the ends of the muscle fibers, which stretch toward them like a fingered glove 1 . The sarcolemma is the center of the liaison between muscle fibers and tendon tissue. The collagen fibrils 3 also pervade the spaces between the finger-like plasmalemma processes of the muscle fiber ends. They are anchored in the outer sarcolemma. A capillar y in the immediate vicinity 4 is a regular part of the skeletal muscle-tendon linkage  (myotendinal connection).

1 Muscle fiber end with myofibrils

2 F ibrocytes (tenocytes)

3 Collagen fibrils of the tendon

4 Capillary with erythrocytes

Electron microscopy; magnification: × 4250

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgar t · New York .