Masters Degrees (Anatomy and Histology)

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Browsing Masters Degrees (Anatomy and Histology) by Author "Mac Dermott, Kerryn-Anne"

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    Histochemical properties of the iliocapsularis muscle: implications for hip function.
    (Stellenbosch : Stellenbosch University, 2023-03) Mac Dermott, Kerryn-Anne; Keet, Kerri; Kohn, Tertius Abraham; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences. Anatomy and Histology. Division of Clinical Anatomy.
    ENGLISH ABSTRACT: The iliocapsularis (IC) is a deep skeletal muscle that overlies and attaches to the anteromedial hip joint capsule and is an important anatomical landmark in anterior approaches to hip replacement surgery. Researchers have proposed the IC functions to stabilise the anterior hip joint and limit impingement of the hip capsule, between the femoral head and acetabulum, in hip flexion. However, a conclusive description of the function of the IC is not yet known. This study, therefore, aims to determine the skeletal muscle properties of the IC muscle and to compare these to that of the iliacus (IL) and vastus lateralis (VL). A cross-sectional observational study was conducted on 11 recently deceased unembalmed bodies with a mean age of 83 ± 9 years (range 69 - 95 years). Muscle samples, harvested from the IC, IL, and VL, were analysed for muscle fibre type distribution and fibre cross-sectional area (CSA) using fluorescent immunohistochemistry, while relative mitochondrial density was visualised histochemically using the NADH stain. IC had predominantly type I fibres (63 ± 12%), followed by type IIA (32 ± 13%) and IIX (5 ± 3%) fibres. IL comprised of a similar high distribution of type I fibres (61 ± 8%), compared to type IIA (31 ± 7%) and IIX (8 ± 8%) fibres. Conversely, VL had equal amounts of type I (47 ± 12%) and IIA (40 ± 11%) fibres, with lower proportions of type IIX (13 ± 10%) fibres. No difference in fibre type distributions were found between the IC and IL, whereas VL had less type I fibres compared to the IC and IL. The latter two muscles observed higher relative mitochondrial density (darker fibres) and, therefore, oxidative capacity, compared to the VL with a more equal proportion of light and dark stained fibres. The IC had larger (p < 0.0001) type I fibres (3607 ± 1422 μm2) compared to its type IIA (1849 ± 1306 μm2) and IIX (1379 ± 900 μm2) fibres. Similarly, the IL and VL had larger (p < 0.0001) type I fibres (3320 ± 1182 μm2 and 4235 ± 882 μm2, respectively) compared to type IIA (1790 ± 987 μm2 and 2738 ± 1650 μm2, respectively) and IIX (1428 ± 769 μm2 and 2170 ± 1355 μm2, respectively) fibres. No difference in the CSA of fibre types were found when the IC was compared with the IL and VL. However, the VL reported larger CSA compared to IL for type I and IIA fibres. Mean fibre CSA of the IC and IL were similar in size, while the VL had larger fibres. Fibre type distribution and fibre CSA showed no association with age. Therefore, the predominant oxidative type I fibre distribution of the IC may supports its proposed function to stabilise the hip joint and limit impingement of the hip capsule in hip flexion. Therefore, conclusive knowledge of the function of the IC will allow for more informed decisions regarding patient care and rehabilitation following anterior approaches for hip-replacement surgery.