Frozen shoulder

This refers to the equivalent of shoulder periarthritis, and is caused by a lesion based on age-related changes in the tissues surrounding the shoulder joint. It is also called 'frozen shoulder' or 'forty-year-old shoulder' because it is common in middle-aged and elderly people. Changes around the joint include tendinitis, tendonitis, rotator cuff damage, bursitis, and capsulitis. There are cases that develop acutely and cases that worsen chronically, but the main symptoms are pain in the shoulder joint and limited movement.

Moving the upper limbs causes severe pain in the shoulder joint, and the pain can also interfere with sleep at night. The degree of movement restriction varies, but patients may be unable to perform everyday activities, such as being unable to comb their hair because they cannot lift their arms or rotate their upper arms (cannot rotate them externally or internally), being unable to tie a belt because they cannot move their hands behind their backs, or being unable to reach their back trouser pockets. In some cases, the upper limbs can hardly be lifted at all. Because of the severe movement disorder, the condition is also known as frozen shoulder.

Symptoms are mild at first, but gradually get worse and cause severe movement restrictions, but then gradually improve. In most cases, symptoms disappear within six months, or at the latest within a year. It is rare for both shoulder joints to be affected at the same time, but it may occur in the other shoulder joint after healing.

Conservative therapy is used for treatment. In other words, local heat is good, and painkillers and anti-inflammatory drugs are taken orally and local anesthetic injections are used to relieve pain. It is necessary to exercise the shoulder joint as long as the pain is not severe, and at home bathing and upper limb exercises should be performed sufficiently. For prevention, it is considered good to exercise the upper limbs frequently on a daily basis, and it is also important to be mindful of not making sudden and unreasonable movements of the upper limbs.

[Takashi Nagai]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

肩(かた)関節周囲炎に相当するものをさし、肩関節の周囲組織の老人性変化を基盤とした病変によっておこる。中老の人に多いところから五十肩とか四十肩とよばれる。関節周囲の変化としては腱(けん)炎、腱鞘(けんしょう)炎、腱板損傷、滑液包炎、関節包炎などがある。急性に発症するものと慢性に症状が増悪するものがあるが、主症状は肩関節の疼痛(とうつう)と運動制限である。

　上肢を動かすと肩関節の疼痛が強く、また夜間に疼痛のため睡眠が妨げられることもある。運動制限の程度はいろいろであるが、上肢があがらず、また上腕が回らない（外旋、内旋ができない）ので頭髪がとかせないとか、手が後ろに回らないので帯が結べない、ズボンの後ろのポケットに手が入らないなど、日常動作ができなくなる。上肢がほとんどあがらなくなることもある。このように運動障害が強いことから、凍結肩frozen shoulderともよばれる。

　症状が初めは軽く、だんだんと重くなって運動制限が高度になっても、その後は徐々に症状が軽快していく。多くは6か月、遅くとも1年以内に症状は消失する。両側の肩関節に同時にくることはほとんどないが、治ってから他側の肩関節に発生することがある。

　治療としては保存的療法が行われる。すなわち、局所の温熱がよく、鎮痛消炎剤の内服や局所麻酔剤などの注射が疼痛を除くために行われる。疼痛の強くない程度に肩関節の自働運動をすることが必要で、家庭では入浴と上肢の体操を十分に行うようにする。予防にも、上肢の運動を日ごろからよく行っておくことがよいと考えられ、また上肢の無理な急激な動作をしないように心がけることである。

［永井　隆］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例