**Core Concept**
Idiopathic polymyositis is an inflammatory muscle disease characterized by progressive muscle weakness. The condition affects **skeletal muscles**, leading to various clinical manifestations. The disease's pathophysiology involves immune-mediated damage to muscle fibers.

**Why the Correct Answer is Right**
The correct answer is related to the typical presentation of idiopathic polymyositis. The condition commonly involves **proximal limb muscles** and can affect **pharyngeal muscles**, leading to dysphagia. **Cutaneous manifestations** can also occur, especially when associated with dermatomyositis. However, **ocular muscles** are typically spared in idiopathic polymyositis.

**Why Each Wrong Option is Incorrect**
**Option B:** Pharyngeal muscles can be involved, leading to swallowing difficulties.
**Option C:** Cutaneous manifestations can occur, especially in dermatomyositis, which is closely related to polymyositis.
**Option D:** Proximal limb muscles are indeed invariably involved, which is a hallmark of the disease.

**Clinical Pearl / High-Yield Fact**
Idiopathic polymyositis should be differentiated from other myopathies based on clinical presentation and laboratory findings. A key point to remember is the sparing of **ocular muscles**, which helps in distinguishing it from other conditions like myasthenia gravis.

**Correct Answer:** A. Ocular muscles commonly involved