Chapter 24: ORTHOPEDICS AND SPORTS MEDICINE

EPIPHYSIS, PHYSIS, AND METAPHYSIS

Starting at either end of the bone, you have the epiphysis, then the physis (growth plate), then the metaphysis, and then the midsection of the bone (diaphysis). KNOW IT.

IMAGE: www.pbrlinks.com/PHYSIS1
IMAGE: www.pbrlinks.com/PHYSIS2

• PHYSIS (AKA EPIPHYSEAL PLATE): Growth plate
• EPIPHYSIS: The rounded end portion of a bone that is most distal to the diaphysis (mid-section of the bone).
  • MNEMONIC: EPI-PHYSIS = ON TOP OF – THE GROWTH PLATE. Think of this as the “distal” part of the bone. This could be farthest away from your joint (imagine using your shoulder joint and humerus for the example), or you could imagine it as being farthest away from the mid-section of a bone (diaphysis). If none of that helps, think of an ice cream cone. Slipped Capital Femoral Epiphysis occurs due to a Type I fracture when the EPIphysis slides off the TOP OF the growth plate.
• METAPHYSIS: This is also towards the end of the bone, but it is more towards the diaphysis.
  • MNEMONIC: M = Metaphysis = closer to the Midsection of the bone!

SALTER HARRIS FRACTURES

There are five types of Salter Harris fractures (I, II, III, IV, and V) we’ll discuss. As a quick summary, they basically go through the growth plate, through the growth plate + metaphysis, through the growth plate + epiphysis, through the metaphysis + growth plate + epiphysis, or involve a crush injury in which the epiphysis is pushed towards the metaphysis, therefore crushing the growth plate and narrowing that space.

IMAGE: www.pbrlinks.com/SALTER1
IMAGE: www.pbrlinks.com/SALTER2

• TYPE I: SEPARATED or SLIPPED. The fracture is through the growth plate, and the epiphysis has just slipped a little. Look for tenderness to palpation at or near the growth plate and a negative X-ray. Treat with casting for 2 weeks.
• TYPE II: Growth Plate + Metaphysis. Most common. You may do a closed reduction and cast for 4 weeks.
• TYPE III: Growth Plate + Epiphysis. This one is BAD because the fracture goes through the epiphysis and into the growth plate. May require an OPEN reduction and often results in poor bone growth after the injury.
• TYPE IV: THROUGH all three layers. Epiphysis + Growth Plate + Metaphysis. This definitely requires open reduction to preserve the growth plate.
• TYPE V: SMASHED. Crush injury in which the epiphysis is pushed towards the metaphysis, therefore crushing the growth plate and narrowing that space. Can result in poor growth after the injury. The X-ray may essentially look negative, or may show a POSTERIOR FAT PAD. This has the worst prognosis.

IMAGE: This shows the presence of an anterior and a posterior fat pad in an unrelated injury. www.pbrlinks.com/SALTERHARRIS3

MNEMONIC: S-a-l-T-S can help you remember SEPARATED, THROUGH and SMASHED for Types I, IV, and V. A different well-known mnemonic uses SALTR. It conflicts with the mnemonic used in the terminology section, though. Feel free to look it up if you’re struggling with these.

MNEMONIC: If you draw a long bone with the epiphysis at the bottom of the page and you use the growth plate as your point of reference, a pretty good mnemonic can be created. S = STRAIGHT (fracture straight across the growth plate). A = ABOVE the growth plate (a fracture at the metaphysis). L = LOWER than the growth plate (a fracture at the epiphysis). T = THROUGH (a fracture through the metaphysis, growth plate and the epiphysis). E = EVERYTHING (crushed with the epiphysis pushed toward the metaphysis). If you use the same bone drawing to show the various segments of the bone (diaphysis, metaphysis, physis, epiphysis), it will lessen confusion and help build on knowledge.