Parts of a Ribeye Steak – Eye, Cap, Lip and Marbling

All 7 parts on the diagram

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The steak 6

Eye The large center muscle, the longissimus. It gives the steak its name.
Cap The curved outer muscle, the spinalis. Also called the ribeye cap.
Lip The tail beside the eye: thin muscle and fat.
Marbling Flecks of fat inside the lean.
Complexus A small muscle beside the eye, at the front of the ribeye.
Multifidus A small muscle at the backbone side of the steak.

With the bone 1

Rib bone Left on, the steak is a rib steak, or bone-in ribeye.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two of these use it: (1) USDA Agricultural Marketing Service, Institutional Meat Purchase Specifications, Fresh Beef, Series 100, https://www.ams.usda.gov/sites/default/files/media/IMPS_100_Fresh_Beef%5B1%5D.pdf (item 112, ribeye roll: the longissimus dorsi, spinalis dorsi, complexus and multifidus dorsi, with the lip removed; item 112A, lip-on: the lip is the serratus dorsalis and longissimus costarum muscles and related fat on the short plate side; item 112C, ribeye: the longissimus dorsi alone; item 112D, ribeye cap: the spinalis dorsi; item 1112, steaks with the lip removed, sometimes called tail off; item 1103, rib steak, bone-in); (2) Wikipedia, Rib eye steak and Rib steak, text only, https://en.wikipedia.org/wiki/Rib_eye_steak and https://en.wikipedia.org/wiki/Rib_steak (mostly the longissimus dorsi, the eye of the ribeye; the spinalis, the ribeye cap; the complexus, a small muscle at the ribeye's front that may be trimmed off; marbling; a rib steak has the rib bone attached, and in the United States a rib eye is a rib steak with the bone removed); (3) Texas A&M University, Meat Science, Beef Rib Steak, Small End, https://meat.tamu.edu/meat-science/teaching/ansc-307-meats/beef-rib-steak-small-end/ (multifidi, spinalis thoracis, longissimus thoracis, iliocostalis thoracis); (4) USDA Agricultural Marketing Service, Beef Grading Shields, https://www.ams.usda.gov/grades-standards/beef/shields-and-marbling-pictures (marbling: the amount of fat interspersed with lean meat); (5) a search-result passage of Meat, Seafood and Poultry Fabrication (2012), read as a passage and not in full, https://archive.org/details/isbn_9781285027920 (the rib eye roll, lip on, has a lip of fat running along the edge; remove the lip to make the rib eye roll). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no photograph or plate followed. Licence: own work

How it works

The main parts of a ribeye are two muscles: the eye, the large one in the middle, and the cap, which curves around it. Fat lies between them and runs through the eye as marbling.

Read the full guide

The boneless steak

Numbers 1 and 2 are the eye and the cap. Number 3, the lip, is the tail of thin muscle and fat beside the eye; a steak sold tail off has it removed. Number 4 is the marbling. Numbers 5 and 6 are two small muscles, the complexus and the multifidus.

With the bone

Number 7 is the rib bone. Spelled ribeye or rib eye, the parts of a rib eye are the same; with this bone on, the steak is a rib steak.

The cap is the spinalis muscle; the eye is the longissimus.
The complexus is at the front end of the ribeye, and a butcher may trim it off.

Questions and answers

What are the muscles in a ribeye steak?

Mostly the longissimus dorsi, called the eye. Around it lie the spinalis dorsi, called the cap, and the smaller complexus and multifidus. The United States purchase specifications list those four muscles for a ribeye roll.

What is the cap of a ribeye?

The cap is the spinalis dorsi, the curved muscle on the outside of the eye. The United States purchase specifications list it on its own as the ribeye cap.

What is the lip or tail on a ribeye?

The lip is a strip of thin muscle and fat on the side of the eye toward the plate. A steak with it removed is sometimes called tail off.

Is a ribeye the same as a rib steak?

In the United States a ribeye is usually the boneless steak and a rib steak has the rib bone attached. In Australia and New Zealand ribeye means the bone-in steak, and the boneless one is a Scotch fillet.