**Core Concept**
The epiphysis is the rounded end of a long bone, initially separate from the main bone shaft (diaphysis) but later fusing to it through growth plates. An aberrant epiphysis refers to an epiphysis that does not follow the typical pattern of development, often resulting in an extra or misplaced epiphysis.

**Why the Correct Answer is Right**
The base of the 2nd metacarpal bone is an example of an aberrant epiphysis because it is the only metacarpal bone in the hand that has a separate epiphysis at its base. This is in contrast to the other metacarpal bones, which have their epiphyses at the heads or distal ends. The presence of an aberrant epiphysis at the base of the 2nd metacarpal can be significant in radiographic assessments, particularly in cases of trauma or disease.

**Why Each Wrong Option is Incorrect**
**Option A:** The coracoid process is a separate bone that articulates with the scapula and humerus, but it is not considered an epiphysis.
**Option B:** The greater tubercle of the humerus is a bony prominence where the supraspinatus, infraspinatus, and teres minor muscles attach, but it is not an epiphysis.
**Option C:** The base of the 1st metacarpal is a separate epiphysis, but it is not considered aberrant.

**Clinical Pearl / High-Yield Fact**
To recall the location of aberrant epiphyses, remember that the base of the 2nd metacarpal is the only one with a separate epiphysis, while the other metacarpals have their epiphyses at the heads or distal ends.

**✓ Correct Answer: D. Base of 2nd metacarpal**