AbstractsBiology & Animal Science

Lateral hip pain (LHP) is a non-specific, clinical condition, characterised by pain and tenderness over the greater trochanter (GT) of the femur. Primarily, females between the ages of 40 and 70 years are affected, but differential diagnosis of the pathology causing symptoms is difficult. In the past, trochanteric bursitis has been thought to be the primary cause of pain, but recently pathology and atrophy of the hip abductor muscles, gluteus medius (GMed) and gluteus minimus (GMin), has been observed in these individuals. Little information is available on the anatomy of the hip abductor muscles, despite inference of their roles in specific movements of the hip joint and their association with LHP. A lack of comprehensive understanding of the normal anatomy of these muscles may explain the problems with accurately diagnosing pathologies implicated in LHP. With regards to treatment of lower limb dysfunction, the posterior part of GMed is often targeted, but there is little anatomical evidence to support the compartmentalisation of this muscle, and hence the effectiveness of these interventions. To further inform clinical practice it is necessary that the detailed morphology of the hip abductor muscles be described. The main purposes of this thesis are (1) to determine the detailed morphology of GMed, GMin and tensor fascia lata (TFL), including fibre type composition and volumes of these muscles in cadavers; (2) compare these data with that obtained from living individuals, and (3) investigate the differences in muscle volume, atrophy and radiological diagnoses of pathologies in the hips of patients with LHP compared to age and sex-matched controls. In the dissection component of this study, the three hip abductor muscles were examined in 12 cadaveric specimens. Details pertaining to attachment sites, fascicle orientation, fascicle and muscle architecture and volumes, tendon dimensions and innervation patterns were collected. Based upon these data, compartmentalisation of the muscles was determined. This study revealed that the anatomy of the hip abductor muscles is more complex than portrayed in the literature. It was found that GMed could be anatomically compartmentalised into either three or four distinct parts, but GMin and TFL were deemed homogenous structures. Also, the boundary between the musculotendinous junction (MTJ) and the free tendon within the tendinous complex of GMed was defined; at the level of the apex of the greater trochanter (GT). Such information is significant when considering the diagnoses and treatment of LHP. The second part to this thesis utilised the contralateral limb from six of the cadaveric specimens used for dissection, in order to determine the fibre type composition of GMed, GMin and TFL, using immunohistochemistry. It was found that GMed was comprised of approximately even amounts of type I and type II muscle fibres. GMin had the lowest percentage of type II muscle fibres, while TFL had the greatest percentage of type II fibres. These preliminary results support the proposed…