What Is the Squamosal?

Also known as skin muscle. Muscles located within the superficial fascia.
Dermal muscle

Also known as skin muscle. Muscles located within the superficial fascia.

Vertebrate skin has a special plate-like base layer that is separated from the surface layer of skeletal muscle. Most of the origins are in the trunk muscles, limb muscles, or pharyngeal muscles. When contracting, only the attached skin and scales, feathers, hair and other activities are caused.

Chinese name

Skin muscle

Foreign name

dermal muscle

Explanation

Under ectoderm or endoderm

Explain

A thin layer

Dermatology 1. Classification and Histological Structure

According to the location and source can be divided into trunk skin muscles and cervical skin muscles. The former is innervated by the spinal nerve, and the latter is innervated by the facial nerve of the brain. The cervical dermatus forms the superficial and deep cervical sphincter. The superficial cervical sphincter is more developed in some animals, also known as the broad neck muscle, forming the cervical and facial muscles. The cervical musculoskeletal muscle bundle runs longitudinally, and is closely attached to the pectoral muscles and the arm muscles, and continues to the head to become the facial skin muscles. The fascia muscle bundle runs toward the mouth, and the muscle bundles are mixed into the mouth and lower lip muscles. The deep cervical sphincter is a series of semicircular muscle bundles that bypass the ventral side of the neck. The role of the skin muscle is mainly to tense and shake the skin; the facial skin muscle can still pull the mouth angle backwards.

Skin Muscle 2. Related Diseases and Treatment

1. Dermatomyositis (DM) is an autoimmune connective tissue disease characterized by involving the skin and striated muscle.

2.Etiology and pathogenesis

The cause of DM is unknown until now and is known to be related to heredity, tumors, drugs, chemicals, infections, and immune mechanisms.

3.Classification

The researchers classified the disease into five types: type is polymyositis; type is dermatomyositis; type is PM / DM (paraneoplastic dermatomyositis) with malignant tumors; and type is children ( Juvenile) type dermatomyositis; type V is PM / DM with collagen vascular disease (overlapping syndrome).

4.Diagnostic criteria

Five diagnostic criteria for DM: weak symmetry of the proximal muscles of the extremities; muscle biopsy consistent with histopathological changes of myositis; elevated serum muscle enzymes, especially elevated CK and aldolase, followed by LDH High; characteristic EMG changes: myogenic damage-short polyphasic motor units and fibrillation, and abnormal high frequency repetitive discharge; characteristic skin lesions, namely Heliotrope rash and Gottron sign. When clinically meeting the above 3 or 4 conditions (with skin lesions), the diagnosis can be confirmed as DM; when 4 conditions (with no skin lesions) are met, the diagnosis can be confirmed as PM; when 2 conditions (with skin lesions) are met The possibility of diagnosing DM is very high; the probability of diagnosing PM is very high when 3 conditions are met (no skin lesions); it is possible to be diagnosed as DM when 1 condition is met (skin lesions); when 2 conditions are met (No skin lesions) may be diagnosed as PM. Another researcher proposed that the following diagnostic criteria should be added when diagnosing DM: myalgia; anti-Jo-1 antibody positive; non-destructive arthritis or joint pain; systemic inflammatory signs (fever, increased erythrocyte sedimentation, etc.) ).

5. Clinical manifestations

Cardiopulmonary disease DM lung involvement rate is 9% to 30%, while pulmonary function abnormality is about 40%, mainly causing 3 kinds of lesions: interstitial pneumonia (41%); diffuse alveolitis (36.2% ); occlusive organizing pneumonia (22.8%). Among them, the prognosis of DM complicated with interstitial pneumonia is worse than that of DM alone, and the mortality is second only to those with DM complicated with tumor. Lactate dehydrogenase (LDH) is more than 4 times more active in lung tissues than in serum, so a sudden rise in LDH indicates the presence of lung and pleural lesions. Interstitial lungs also occur when LDH is not elevated and Jo-1 antibody is positive. Risk of lesions. Non-myogenic DM may also cause fatal interstitial pneumonia, and the main indication for cyclophosphamide (CTX) shock therapy is interstitial pneumonia. 40% of patients with this disease have abnormal electrocardiogram (ECG), including changes in ST-T segment and Q wave, bundle branch block, congestive heart failure and arrhythmia. Although pericarditis is rare, cardiac tamponade can cause death and should be taken seriously. Serum muscle enzymes can also be elevated during myocardial involvement. Its clinical significance is that skin lesions can occur simultaneously with muscle weakness or before and after.

6.Treatment

Application of glucocorticoids and immunosuppressants. All types of DM need to be treated with glucocorticoids. In severe cases, glucocorticoid shock treatment can be used. However, fluoroglucocorticoids such as dexamethasone and triamcinolone can easily cause proximal muscle And pelvic muscle weakness, known as hormone myopathy, is not suitable for the treatment of this disease.

Treatment of DM lesions:

Treatment methods include: external use of light-shielding drugs with high ultraviolet protection index (SPF); topical glucocorticoids, especially high-efficiency glucocorticoids, are helpful for the treatment of skin lesions; hydroxychloroquine 0.2 0.4g / d Apine 0.1g / d); For those who are resistant to conventional treatment, consider giving small doses of MTX (ranging from 2.5 to 30 mg per week), which can often reduce or even stop the use of glucocorticoids; long-wave ultraviolet (UVA ) Treatment; Thalidomide is effective for localized skin lesions; Patients with malignant erythema should carefully check for tumors, and the erythema can gradually disappear after the tumor is removed.