Stephanie J. Woodley

Hamstring Muscles: Architecture and Innervation

Knowledge of the anatomical organization of the hamstring muscles is necessary to understand their functions, and to assist in the development of accurate clinical and biomechanical models. The hamstring muscles were examined by dissection in six embalmed human lower limbs with the purpose of clarifying their gross morphology. In addition to obtaining evidence for or against anatomical partitioning (as based on muscle architecture and pattern of innervation), data pertaining to architectural parameters such as fascicular length, volume, physiological cross-sectional area, and tendon length were collected. For each muscle, relatively consistent patterns of innervation were identified between specimens, and each was unique with respect to anatomical organization. On the basis of muscle architecture, three regions were identified within semimembranosus. However, this was not completely congruent with the pattern of innervation, as a primary nerve branch supplied only two regions, with the third region receiving a secondary branch. Semitendinosus comprised two distinct partitions arranged in series that were divided by a tendinous inscription. A singular muscle nerve or a primary nerve branch innervated each partition. In the biceps femoris long head the two regions were supplied via a primary nerve branch which divided into two primary branches or split into a series of branches. Being the only muscle to cross a single joint, biceps femoris short head consisted of two distinct regions demarcated by fiber direction, with each innervated by a separate muscle nerve. Architecturally, each muscle differed with respect to parameters such as physiological cross-sectional area, fascicular length and volume, but generally all partitions within an individual muscle were similar in fascicular length. The long proximal and distal tendons of these muscles extended into the muscle bellies thereby forming elongated musculotendinous junctions.

The adult human pubic symphysis: a systematic review

The pubic symphysis is a unique joint consisting of a fibrocartilaginous disc sandwiched between the articular surfaces of the pubic bones. It resists tensile, shearing and compressive forces and is capable of a small amount of movement under physiological conditions in most adults (up to 2 mm shift and 1° rotation). During pregnancy, circulating hormones such as relaxin induce resorption of the symphyseal margins and structural changes in the fibrocartilaginous disc, increasing symphyseal width and mobility. This systematic review of the English, German and French literature focuses on the normal anatomy of the adult human pubic symphysis. Although scientific studies of the joint have yielded useful descriptive data, comparison of results is hampered by imprecise methodology and/or poorly controlled studies. Several aspects of the anatomy of the pubic symphysis remain unknown or unclear: the precise attachments of surrounding ligaments and muscles; the arrangement of connective tissue fibres within the interpubic disc and the origin, structure and function of its associated interpubic cleft; the biomechanical consequences of sexual dimorphism; potential ethnic variations in morphology; and its precise innervation and blood supply. These deficiencies hinder our understanding of the normal form and function of the joint, which is particularly relevant when attempting to understand the mechanisms underlying pregnancy‐related pubic symphyseal pain, a neglected and relatively common cause of pubic pain. A better understanding of the normal anatomy of the human pubic symphysis should improve our understanding of such problems and contribute to better treatments for patients suffering from symphyseal pain and dysfunction.

Lateral Hip Pain: Findings From Magnetic Resonance Imaging and Clinical Examination

STUDY DESIGN Prospective cross-sectional study. OBJECTIVES To examine the radiological and physical therapy diagnoses of lateral hip pain (LHP), and determine the validity of selected clinical variables for predicting gluteal tendon pathology. BACKGROUND LHP is frequently encountered by clinicians. Further investigation is required to establish the specific pathologies implicated in the cause of LHP, and which clinical tests are useful in the assessment of this problem. METHODS AND MEASURES Forty patients with unilateral LHP underwent a physical therapy examination followed by magnetic resonance imaging (MRI) studies. Three radiologists analyzed the images of both hips for signs of pathology. Interobserver reliability of the image analyses, the agreement between the physical therapy and radiological diagnoses, and the validity of the clinical tests were examined. RESULTS Gluteus medius tendon pathology, bursitis, osteoarthritis and gluteal muscle atrophy (predominantly affecting gluteus minimus) were all implicated in the imaging report of LHP. While prevalent in symptomatic hips, abnormalities were also identified in asymptomatic hips, particularly relating to the diagnosis of bursitis. The strength of agreement between radiologists was variable and little agreement existed between the physical therapy and radiological diagnoses of pathology. Nine of the 26 clinical variables examined in relation to gluteal tendon pathology had likelihood ratios above 2.0 or below 0.5, but the associated 95% confidence intervals were large. CONCLUSIONS The diagnosis of LHP is challenging and our results highlight some problems associated with the use of MRI as a diagnostic reference standard. This factor, together with the imprecise point estimates of the likelihood ratios, means that no firm conclusions can be made regarding the diagnostic utility of the clinical tests used in the assessment of gluteal tendon pathology.

A review of the anatomy of the hip abductor muscles, gluteus medius, gluteus minimus, and tensor fascia lata.

The hip abductor muscles have the capability to contribute to numerous actions, including pelvic stabilization during gait, and abduction and rotation at the hip joint. To fully understand the role of these muscles, as well as their involvement in hip joint dysfunction, knowledge of their anatomical structure is essential. The clinical literature suggests anatomical diversity within these muscles, and that gluteus medius (GMed) and gluteus minimus (GMin), in particular, may be comprised of compartments. This systematic review of the English literature focuses on the gross anatomy of GMed, GMin, and tensor fascia lata (TFL) muscles. Although studies of this muscle group have generated useful descriptions, comparison of results is hindered by methodological limitations. Furthermore, there is no single comprehensive anatomical investigation of all three muscles. Several aspects of the morphology of attachment sites are unknown or unclear. There is little data on fascicle orientation, the interface between fascicles and tendons, and the specific patterning of the superior gluteal nerve. Consequently, the existence of anatomical compartmentalization within the hip abductor muscles is difficult to assess. Further research of the architecture and innervation of the hip abductor muscle group is required; a better understanding of the precise anatomy of these muscles should improve our understanding of their specific functions and their contribution to the pathogenesis of disorders affecting the hip joint. Clin. Anat. 25:697–708, 2012.

The vastus lateralis muscle: an anatomical investigation.

Anterior knee pain or patellofemoral pain syndrome is commonly encountered by clinicians, but the pathogenesis of this condition is not well understood. While much research has centred around the relationship between vastus medialis and anterior knee pain, little is known about the most lateral of the quadriceps muscle group, vastus lateralis (VL). Knowledge of the anatomical organization of VL is not only necessary to understand its precise function, but to also assist in the development of clinical and biomechanical models of knee dysfunction. The purpose of this study was to investigate the detailed morphology of VL, specifically to provide data relating to architecture, attachment sites, innervation, and the presence of anatomical partitioning within the muscle. The VL muscle was examined in 10 cadaveric lower limbs using macrodissection techniques. On the basis of architecture and innervation, this muscle comprised four partitions with each receiving its own unique nerve branch. The mean fascicular length of VL was 7 cm and the mean fascicular and muscle physiological cross‐sectional areas were 1.2 cm2 and 21.6 cm2, respectively. In addition to inserting proximally at the base of the greater trochanter and distally into the superolateral border and base of the patella, three additional attachment sites were identified: the lateral intermuscular septum, iliotibial band, and the rectus tendon. The results of this study suggest that the gross morphology of VL is more complex than previously described, and the information provided regarding architecture will contribute to knowledge regarding the function of VL as well as its role in knee joint dysfunction. Clin. Anat. 23:575–585, 2010.

The anatomy of the hip abductor muscles

The anatomy of the hip abductors has not been comprehensively examined, yet is important to understanding function and pathology in the gluteal region. For example, pathology of the hip abductor muscle‐tendon complexes can cause greater trochanteric pain syndrome, and may be associated with gluteal atrophy and fatty infiltration. The purpose of this study was to investigate the detailed morphology of gluteus medius (GMed), gluteus minimus (GMin), and tensor fascia lata (TFL), and determine whether the muscles comprised anatomical compartments. The gluteal region from 12 cadavers was dissected and data collected on attachment sites, volume, fascicular and tendinous anatomy, and innervation. Three sites of GMed origin were identified (gluteal fossa, gluteal aponeurosis, and posteroinferior edge of the iliac crest) and the distal tendon had lateral and posterior parts. GMed was the largest in volume (27.6 ± 11.6 cm3; GMin 14.1 ± 11.1 cm3; TFL 1.8 ± 0.8 cm3). Fascicles of GMin originated from the gluteal fossa, inserting onto the deep surface of its distal tendon and the hip joint capsule. TFL was encapsulated in the fascia lata, having no bony attachment. Primary innervation patterns varied for GMed, with three or four branches supplying different regions of muscle. Distinct secondary nerve branches entered four regions of GMin; no differential innervation was observed for TFL. On the basis of architectural parameters and innervation, GMed, and GMin each comprise of four compartments but TFL is a homogenous muscle. It is anticipated that these data will be useful for future clinical and functional studies of the hip abductors. Clin. Anat. 27:241–253, 2014.

Effects of external pelvic compression on form closure, force closure, and neuromotor control of the lumbopelvic spine – A systematic review

Optimal lumbopelvic stability is a function of form closure (joint anatomy), force closure (additional compressive forces acting across the joints) and neuromotor control. Impairment of any of these mechanisms can result in pain, instability, altered lumbopelvic kinematics, and changes in muscle strength and motor control. External pelvic compression (EPC) has been hypothesised to have an effect on force closure and neuromotor control. However, the specific application parameters (type, location and force) and hypothesized effects of EPC are unclear. Thus, a systematic review was conducted to summarize the in vivo and in vitro effects of EPC. Eighteen articles met the eligibility criteria, with quality ranging from 33% to 72% based on a modified Downs and Black index. A modified van Tulders rating system was used to ascertain the level of evidence synthesised from this review. There is moderate evidence to support the role of EPC in decreasing laxity of the sacroiliac joint, changing lumbopelvic kinematics, altering selective recruitment of stabilizing musculature, and reducing pain. There is limited evidence for effects of EPC on decreasing sacral mobility, and affecting strength of muscles surrounding the SIJ, factors which require further investigation.

Gross morphology of the vastus lateralis muscle: An anatomical review.

To understand the role of the vastus lateralis (VL) muscle in the pathogenesis of common knee disorders such as patellofemoral joint syndrome, knowledge of its anatomical structure is essential. The aim of this study was to review currently available information on the gross morphology of VL. A structured literature review was undertaken and 36 references, comprising 22 scientific papers and 14 anatomical textbooks, were included. Results of this literature review show that most of the included studies exhibited methodological limitations, and focused on different parameters of the VL muscle. Hence, reproducibility of these studies and comparison of results was difficult. This review also demonstrates a dearth of information on the muscle architecture, compartmentalization, nerve supply and fusion of VL, and that there has been no investigation of the muscle as a whole unit. Further research is required of the architecture and innervation of the VL muscle to better understand its function. Clin. Anat. 22:436–450, 2009.

New insights into the proximal tendons of adductor longus, adductor brevis and gracilis

Objective The adductor muscles are implicated in the pathogenesis of groin strain, but the proximal morphology of this muscle group is poorly defined. The purpose of this study was to investigate the detailed anatomy of the entheses and proximal musculotendinous junctions (MTJs) of adductor longus (AL), adductor brevis (AB) and gracilis. Methods The adductors were dissected bilaterally in 10 embalmed cadavers (7 females, mean age at death 79 years (range 57–93 years)), focusing on the type of enthesis, and architecture of the proximal tendons and MTJs. Histology was used to determine if the entheses contained fibrocartilage and to semiquantitatively assess the vascularity of each proximal tendon. Results All entheses were fibrocartilaginous. The proximal tendons of AB and gracilis were fused, forming a common tendinous insertion in all specimens. AL and AB both contained extensive intramuscular tendons of variable length (AL 11.1 ± 1.5 cm; AB 5.4 ± 1.1 cm); this has not been recorded previously. The vascularity of AL and AB tendons decreased significantly towards the enthesis (p < 0.05), and their entheses were significantly less vascular than that of gracilis (p < 0.05). Conclusions The proximal anatomy of AL, AB and gracilis is more complex than previously described. The arrangement and fusion of these muscles, their fibrocartilaginous entheses and differences in vascularity of their proximal tendons may be important anatomical considerations in the pathogenesis and pattern of adductor-related groin pain.

Ligament of the head of femur: A comprehensive review of its anatomy, embryology, and potential function

The functional significance of the ligament of the head of femur (LHF), or ligamentum teres has often been debated. Having gained recent attention in clinical practice, it is suggested to partly provide some mechanical stability to the hip joint. However, the anatomy of this ligament is not well studied. This paper systematically reviews the anatomy of the LHF with the aim of exploring our current understanding of this structure and identifying any gaps in knowledge regarding its morphology and function. A systematic search of Medline, Embase, ProQuest, Web of Science, and Scopus databases was undertaken and relevant data extracted, analyzed. A total of 69 references were obtained, that included 53 full text articles, three published abstracts, and 13 textbooks. Many publications related to clinical studies (n = 11) rather than gross anatomy (n = 7), with one report on variation of the LHF. Considerable inconsistency in the naming and description of the LHF morphology was observed. Variable attachment sites were reported except for the acetabular notch, transverse acetabular ligament, and the femoral fovea. Presence and patency of the ligamental arteries supplying the head of the femur and their exact location were variably described and were often incomplete. The LHF is believed to be taught in extreme hip adduction, but there is little evidence to support this. In conclusions, further investigation of the anatomy of the LHF is recommended, particularly to clarify its mechanical role, innervation, and vascular contribution to the developing and adult femur, so to better inform clinical practice. Clin. Anat. 29:247–255, 2016.