Upper-Crossed Syndrome
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Clinically Relevant Anatomy[edit | edit source]
Upper-crossed syndrome (UCS) is also referred to as proximal or shoulder girdle crossed syndrome. In UCS, tightness of the upper trapezius and levator scapula on the dorsal side crosses with tightness of the pectoralis major and minor. Weakness of the deep cervical flexors ventrally crosses with weakness of the middle and lower trapezius. This pattern of imbalance creates joint dysfunction, particularly at the atlanto-occipital joint, C4-C5 segment, cervicothoracic joint, glenohumeral joint, and T4-T5 segment. Janda noted that these focal areas of stress within the spine correspond to transitional zones in which neighboring vertebrae change in morphology. Specific postural changes are seen in UCS, including forward head posture, increased cervical lordosis and thoracic kyphosis, elevated and protracted shoulders, and rotation or abduction and winging of the scapulae.. These postural changes decrease glenohumeral stability as the glenoid fossa becomes more vertical due to serratus anterior weakness leading to abduction, rotation, and winging of the scapulae. This loss of stability requires the levator scapula and upper trapezius to increase activation to maintain glenohumeral centration.
Mechanism of Injury / Pathological Process[edit | edit source]
There are two schools of thought on muscle imbalance: one that believes in a biomechanical cause of muscle imbalance resulting from repetitive movements and posture and one that believes in a neurological predisposition to muscle imbalance. Both biomechanical and neurological muscle imbalance are seen clinically, so clinicians must understand both in order to make a more accurate diagnosis and treatment. Patients may also exhibit hybrid muscle imbalance syndromes consisting of factors from each paradigm, further challenging clinicians as they work to prescribe the appropriate treatment.
V. Janda said: For example, unbalanced biomechanical joint stresses that result from muscle imbalance may lead to joint damage, setting up a vicious cycle of pain and inflammation. The structural inflammation then affects the neuromuscular system of the joint, creating further dysfunction. Eventually, the body adapts the motor program for movement to compensate for the dysfunction. The functional cause of the problem is muscle imbalance, while the symptom is pain and inflammation resulting from a structural lesion. Therefore, it is possible to have both a structural and a functional lesion, but for accurate diagnosis and treatment, the clinician must decide which lesion is the actual cause of dysfunction.
Muscle balance can be defined as a relative equality of muscle length or strength between an agonist and an antagonist; this balance is necessary for normal movement and function. Muscle balance may also refer to the strength of contralateral (right versus left) muscle groups.Muscles may become unbalanced as a result of adaptation or dysfunction. Such muscle imbalances can be either functional or pathological.Functional muscle imbalances occur in response to adaptation for complex movement patterns, including imbalances in strength or flexibility of antagonistic muscle groups.
| Functional imbalance | Pathological imbalance |
|---|---|
| Atraumatic | With or without trauma |
| Adaptive change | Adaptive change |
| Activity specific | Associated with dysfunction |
| No pain | With or without pain |
When muscle imbalance impairs function, it is considered to be pathological. Pathological muscle imbalance typically is associated with dysfunction and pain, although its cause may or may not result from an initial traumatic event. Pathological imbalance may also be insidious; many people have these muscle imbalances without pain. Ultimately, however, pathological muscle imbalance leads to joint dysfunction and altered movement patterns, which in turn lead to pain. Note that this muscle imbalance continuum may progress in either direction; muscle imbalance may lead to altered movement patterns and vice versa.
Some injuries cause muscle imbalance, while others may result from muscle imbalance.
Sometimes pathological imbalances are a functional compensation for an injury
Clinical Presentation[edit | edit source]
muscules.
Diagnostic Procedures[edit | edit source]
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Outcome Measures[edit | edit source]
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Management / Interventions[edit | edit source]
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Differential Diagnosis[edit | edit source]
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Resources[edit | edit source]
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