Denis classification of sacral fractures

⚪️ There are several classification systems for sacral fractures, but the most commonly employed are the Denis classification and subclassification systems, and the Isler classification system.

⚪️ Denis classification: 

• zone 1: fracture involves the sacral ala lateral to the neural foramina

• zone 2: fracture involves the neural foramina, but does not involve the spinal canal.

• zone 3: fracture is medial to the neural foramen, involving the spinal canal; these may be transverse or longitudinal, and can be sub-classified into 4 types:

• type 1: only kyphotic angulation at the fracture site (no translation).

• type 2: kyphotic angulation with anterior translation of the distal sacrum.

• type 3: kyphotic angulation with complete offset of the fracture fragments.

• type 4: comminuted S1 segment, usually due to axial compression.

⚪️ Morphologic injury patterns of zone 3 fractures:

🔶️ “H” shaped fracture

🔶️ “U” shaped fracture

🔶️ “ʎ” (lambda) shaped fracture

🔶️ “T” shaped fracture

Ureterocele

⚪️ Contrast enhanced pelvic CT showing a well-defined intravesical cystic outpouching at the left ureteric orifice with the characteristic cobra-head appearance.

⚪️ These findings are consistent with left ureterocele.

Ulnar variance radiology

⚪️ Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna and is primarily a plain radiographic determination. 

⚪️ Ulnar variance may be:

🔲 Neutral (both the ulnar and radial articular surfaces at the same level)

➕️ Positive (ulna projects more distally)

➖️ Negative (ulna projects more proximally)

⚪️ Variance is independent of the length of the ulnar styloid process.