**Core Concept**
Luxatio erecta is a type of dislocation where the head of the humerus is displaced superiorly and posteriorly, resulting in an arm that appears to be "locked in" an overhead position. This type of dislocation is often associated with fractures of the greater tuberosity of the humerus.

**Why the Correct Answer is Right**
Luxatio erecta occurs due to a combination of external rotation, abduction, and extension forces acting on the shoulder joint. The humeral head is forced out of the glenoid cavity, resulting in a dislocation. The greater tuberosity of the humerus, which is the attachment point for the supraspinatus tendon, often fractures in this type of dislocation. The fracture and dislocation can be difficult to diagnose, especially in the absence of a clear history of trauma.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because luxatio erecta is not characterized by a posterior dislocation of the humeral head.
**Option B:** This option is incorrect because luxatio erecta is not associated with a fracture of the coracoid process.
**Option C:** This option is incorrect because luxatio erecta is not a term used to describe a radial head fracture.

**Clinical Pearl / High-Yield Fact**
Luxatio erecta is a classic exam question, and it's essential to remember the characteristic displacement of the humeral head in this type of dislocation. The "locked in" position of the arm is a key clinical finding that should raise suspicion for this diagnosis.

**Correct Answer: C.**