Revisiting the clinical anatomy of the alar ligaments.

PURPOSE: The morphology of the alar ligaments has been inconsistently described, particularly with regard to the existence of an atlantal portion. Despite these inconsistencies, these descriptions have been used to develop physical tests for the integrity of these ligaments in patients with cervical spine problems. The purpose of this study was to describe the detailed macrostructure of the alar ligaments. METHODS: The alar ligaments of 11 cervical spine specimens from embalmed adult cadavers were examined by fine dissection. A detailed description of the macrostructure of these ligaments and their attachment sites was recorded. Measurements were performed with respect to ligament dimensions and relations with selected bony landmarks. RESULTS: No atlantal portion of the alar ligament was viewed in any specimen. The attachment of the ligaments on the odontoid process occurred on its lateral and posterolateral aspects, frequently below the level of the apex. The occipital attachment was on the medial surface of the occipital condyles in close proximity to the atlanto-occipital joints. The orientation of the ligaments was primarily horizontal. The presence of transverse bands extending occiput to occiput with minimal or no attachment to the odontoid process was a common variant. CONCLUSIONS: The absence of findings with respect to the atlantal portion of the alar ligament suggests that it may be considered an anatomical variant, not an essential component for stability of the craniocervical complex. These findings may inform the use and interpretation of clinical tests for alar ligament integrity.

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.

Morphology of the bursae associated with the greater trochanter of the femur.

BACKGROUND: Abnormalities of the bursae in the vicinity of the greater trochanter have been implicated in the pathogenesis of lateral hip pain. The purpose of the present study was to investigate the detailed morphology of the bursae associated with the greater trochanter of the femur. METHODS: The bursae deep to the tendons of each of the gluteal muscles were examined in eighteen embalmed human hips with use of macrodissection and histological techniques. The specimens were obtained from eight female and seven male donors who had had a mean age of seventy-eight years at the time of death. RESULTS: A total of 106 bursae were identified in ten different locations, with an average of six bursae per hip. As many as four bursae were present beneath the gluteus maximus muscle and the fascia lata, including those normally thought of as the "trochanteric" bursae and the gluteofemoral bursa. Two bursae typically were found beneath the tendon of the gluteus medius muscle: the anterior subgluteus medius bursa and the piriformis (posterior subgluteus medius) bursa. In the majority of cases, a single bursa was located deep to the gluteus minimus tendon, although two different bursae were identified: the subgluteus minimus bursa and the secondary subgluteus minimus bursa. All of these bursae demonstrated a synovial lining, which was predominantly areolar in type. CONCLUSIONS: The present study revealed that numerous bursae are intimately associated with the greater trochanter and that at least two bursae are associated with each of the gluteal tendons.

Preliminary observations on the microarchitecture of the human abdominal muscles.

Precise knowledge of muscle architecture and innervation patterns is essential for the development of accurate clinical and biomechanical models. Although the gross anatomy of the human abdominal muscles has been investigated, the finer details of their microanatomy are not well described. Fascicles were systematically sampled from each of the human abdominal muscles, and small fiber bundles from selected fascicles stained with acetylcholinesterase to determine the location of motor endplate bands, myomyonal junctions, and myotendinous junctions. Statistical analysis was used to ascertain the association between fascicular length and number of endplate bands. The number of endplate bands along a fascicle was variable between different portions of each muscle, but was strongly correlated with fascicular length (r = 0.814). In fascicles less than 50 millimeters (mm) in length, only a single endplate band was generally present, while multiple endplate bands (usually two or three) were found in fascicles longer than 50 mm. The presence of myomyonal junctions throughout the longer (>50 mm) fascicles verified that they were composed of short, intrafascicularly terminating fibers, while shorter fascicles comprised fibers spanning the entire fascicular length. This preliminary study provides evidence that multiple endplate bands are contained in some regions of the abdominal muscles, an arrangement that differs from most human appendicular muscles. It is not clear whether the variations in the described fine architectural features reflect regional differences in muscle function.

Intra-articular inclusions of the elbow joint complex.

An abundant clinical literature implicates intra-articular inclusions in various pathological conditions of the elbow, but the anatomical literature offers piecemeal descriptions of these structures. The aim of this study was to determine the prevalence, disposition, and gross morphology of intra-articular inclusions of the entire elbow joint complex. Twenty-eight elbow joints from 17 adult embalmed cadavera were studied by macrodissection. Three types of inclusions were identified. Fat pads and fibroadipose meniscoids were found in all joints while capsular rims occurred in 50% of radiohumeral and humeroulnar joints. Fat pads were located opposite the olecranon, coronoid, and radial fossae. Fibroadipose meniscoids were found in the nonarticular waists of the trochlear notch and protruded into the posterolateral aspect of the radiohumeral joint. Fibroadipose meniscoids and fat pads are characteristic structures of the elbow joint complex. Fat pads appear to act as deformable space fillers, while the radio-humeral fibroadipose meniscoid appears to protect articular cartilage exposed during normal movement. Arguments are raised whether these structures may act as the nidus for arthrofibrosis and that the radiohumeral meniscoid may be involved in lateral epicondylalgia.

The lumbar multifidus muscle and patterns of pain.

This paper describes the patterns of pain induced by injecting hypertonic saline into the lumbar multifidus muscle opposite the L5 spinous process in 15 healthy adult volunteers. All subjects experienced local pain while referred pain was reported by 13 subjects in one of two regions of the thigh; anterior (n=5) or posterior (n=8). These results confirm that the multifidus muscle may be a source of local and referred pain. Comparison of these maps with pain maps following stimulation of the L4 medial dorsal rami and L4-5 interspinous ligaments shows that pain arising from the band of multifidus innervated by the L4 dorsal ramus has a segmental distribution. In addition patterns of pain arising from multifidus clearly overlap those reported for other lumbar structures. These findings highlight the difficulty of using pain distribution to accurately identify specific lumbar structures as the source of pain.

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.

Effects of exposure on perception of pain expression.

The present study evaluated the effects of exposure to facial expression of pain, on observers' perceptions of pain expression. Thirty-one male and 49 female observers judged 1-s video excerpts in a signal detection paradigm. The excerpts showed facial expressions of shoulder-pain patients displaying no pain or moderate pain. Participants were randomly allocated to one of four groups, which varied in the number of prior exposures of a 1 s display of strong pain. On each test trial, participants indicated whether the test stimulus showed no pain or pain. Data were analyzed using signal detection theory methods. There was a linear relationship between the density of exposure to strong pain and observers' response criteria: greater exposure was associated with more conservative decisions. On average, participants showed very high levels of sensitivity to pain expression, with women significantly outperforming men. Results are discussed in terms of their implications for pain judgments of health care professionals, adaptation-level theory, and the psychophysical method of selective adaptation.

Development of sensitivity to facial expression of pain.

The ability to perceive pain in others is an important human capacity. Its development has not been studied. The present study examined the development of sensitivity to evidence of pain from childhood to early adulthood. One hundred and thirty-four males and females from four age groups (5-6, 8-9, 11-12 years and young adult) took part. They judged the amount of pain displayed on videotaped excerpts of the facial expressions of pain patients. Excerpts were selected to display no pain, some pain and strong pain, based on facial measurements, and were displayed to participants in a signal-detection paradigm. All participant groups were more sensitive to evidence of strong than some pain. The ability to detect pain expressions increased across the young, middle and older groups of children, but older children did not differ from adults. Increasing age was generally associated with increasing sensitivity to more subtle facial signs of pain. The results indicate that the ability to perceive pain in others is already significantly developed by the ages of five to six, but refinements in the ability continue through to early adulthood. These findings represent the first description of the development of the ability to perceive pain in others. Important areas for future research into the neurobiological, personal and social determinants of this ability are highlighted.

Clinical anatomy of ligamentum nuchae.

In view of the disparities in the anatomical, clinical, and biomechanical literature this study was undertaken to reappraise the gross anatomy of ligamentum nuchae with the objective of providing an accurate anatomical basis for biomechanical studies and for clinical theories and practices. Ligamentum nuchae was studied by gross dissection in ten embalmed human adult cadavers and was found to be comprised of two structures: a dorsal raphe and a midline fascial septum. The dorsal raphe was formed by the interweaving of the right and left upper trapezius, splenius capitis, and rhomboid minor. It spanned the cervical spine and was firmly attached to the external occipital protuberance and to the spinous process of C7. The fascial septum consisted of dense connective tissue and ran ventrally from the midline raphe to be confluent with the interspinous ligaments and atlanto-axial and atlanto-occipital membranes. These findings agree with those anatomical descriptions that portray ligamentum nuchae as a two-part structure but not with those studies in which it is characterized as a strong ligament attaching to all cervical spinous processes. Importantly, the findings of this study emphasize the need for clinical and biomechanical literature to portray the gross anatomy of ligamentum nuchae accurately.

Encoding and decoding of pain expressions: a judgement study.

The communication of pain requires a sufferer to encode and transmit the experience and an observer to decode and interpret it. Rosenthal's (1982) model of communication was applied to an analysis of the role of facial expression in the transmission of pain information. Videotapes of patients with shoulder pain undergoing a series of movements of the shoulder were shown to a group of 5 judges. Observers and patients provided ratings of the patients' pain on the same verbal descriptor scales. Analyses addressed relationships among patients' pain reports, observers' judgements of patients' pain and measures of patients' facial expressions based on the Facial Action Coding System. The results indicated that although observers can make coarse distinctions among patients' pain states, they (1) are not especially sensitive, and (2) are likely to systematically downgrade the intensity of patients' suffering. Moreover, observers appear to make insufficient use of information that is available in patients' facial expression. Implications of the findings for pain patients and for training of health-care workers are discussed as are directions for future research.

Pain expression in patients with shoulder pathology: validity, properties and relationship to sickness impact.

This study dealt with the validity and correlates of facial expressions of pain. Twenty-four patients seeking treatment for gleno-humeral joint pain and 12 controls underwent a standardized physiotherapy assessment protocol involving active and passive arm movements, and experimental pain induced by pressure. Subjects rated pain intensity on each trial using categorical, sensory and affective scales. Independent of testing, they completed a questionnaire measure of sickness impact. Facial behavior was measured by an abbreviated version of the Facial Action Coding System. Facial actions that related to pain indices included eyebrow lowering, narrowing and closing of the eyes, lip pulling, nose wrinkling and mouth opening. Facial actions during clinical tests showed consistent relationships with sensory and affective pain scales. Greater physical disability was associated with more intense pain actions on active, but not passive, tests. The results support the validity and generality of facial measures of pain, show that they yield graded sensitive information and suggest that they encode information about the psychosocial context of pain problems. Theoretical implications of these findings are discussed.