An Anatomical Study of the Anterosuperior Capsular Attachment Site on the Acetabulum

The ligamentous structures of the triangular fibrocartilage complex (TFCC) and their attachments were examined anatomically and histologically using fresh and embalmed cadavers. The TFCC was observed to have a three-dimensional structure consisting of three palmar ligaments — the short radiolunate (SRL), ulnolunate (UL), and ulnotriquetral (UT) ligaments. In addition, the attachment site of the ulnocarpal ligament (UC), which had been previously unknown, was identified. The dorsal components of the TFCC have been previously reported to consist solely of the extensor carpi ulnaris (ECU) subsheath; however, the ligamentous components running from the ulnar styloid process to the triquetrum were found at a layer deeper than the floor of the ECU subsheath. The UC has been reported previously as a two-dimensional structure, but there has been some disagreement as to its attachment sites.2–6,14,15 It is suggested that the dorsal UT ligament should be considered as a separate ligament, based on its different direction and distal attachment site as compared with those of the ulnar collateral ligament (UCL) and ECU subsheath.

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The Longissimus Capitis Insertion as a Superficial Landmark for the Sigmoid Sinus: An Anatomical Study

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0040-1716890 ◽

2020 ◽

Author(s):

Joe Iwanaga ◽

Koichi Watanabe ◽

Pervez A. Khan ◽

John D. Nerva ◽

Peter S. Amenta ◽

...

Keyword(s):

Attachment Site ◽

Anatomical Study ◽

Sigmoid Sinus ◽

Mastoid Process ◽

Anatomical Landmarks ◽

Knowledge Use ◽

Tendon Insertion ◽

Inferior Border ◽

Burr Holes ◽

Made In

Abstract Objective Many external anatomical landmarks have been used for approximating deeper, intracranial structures. Herein, we evaluate the attachment of the longissimus capitis (LC) on the mastoid process as a landmark for the underlying sigmoid sinus. Methods Adult cadavers underwent dissection of the posterior occiput with special attention to the attachment of the LC muscle. Once the periphery of the muscle's tendon of attachment was determined, a burr hole was made in this area and evaluated internally for its relationship to the sigmoid sinus. Results From an intracranial view, burr holes on all sides were over the sigmoid sinus and just slightly lateral to the center of the sinus. The distance from the midline to the medial border of the insertion of the LC had a mean of 63.0 ± 7.2 mm. The width of the tendon of insertion of the LC on the mastoid process had a mean of 17.6 ± 5.7 mm. The length of the tendon insertion of the LC had a mean of 14.7 ± 4.7 mm. The distance from the inferior border of the insertion of the LC to the tip of the mastoid process had a mean of 6.2 ± 4.5 mm. Conclusion To our knowledge, use of the attachment site of the LC on the mastoid process as an external landmark for the underlying sigmoid sinus has not previously been reported. Based on our cadaveric findings, the sigmoid sinus is centered under the attachment of the LC regardless of the width of its tendon.

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Localization of immunolabels by electron microscopy and image averaging

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075208 ◽

1983 ◽

Vol 41 ◽

pp. 282-283

Author(s):

J. Frank ◽

P.-Y. Sizaret ◽

A. Verschoor ◽

J. Lamy

Keyword(s):

Electron Microscopy ◽

Single Particle ◽

Attachment Site ◽

Uranyl Acetate ◽

Limulus Polyphemus ◽

Resolution Limit ◽

Electron Microscopic ◽

Image Averaging ◽

Top View ◽

Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

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