The Human rib cage
In anatomy, ribs were a bone formation that protected the vital organs in the thorax of most humanoid species. Costal strut was the Malcorian term for this formation. (TNG: "First Contact")
A diagram of the Human torso depicting the location of the ribs was stored in the USS Enterprise's library computer database. This database was accessed by the Talosians in 2254. (TOS: "The Cage")
Kzinti ribs were vertically braced. In 2270, Chuft-Captain suffered two broken ribs after Spock jumped him. (TAS: "The Slaver Weapon")
In Humans, they ran horizontally and met at the breastbone. Klingons were known to have twenty-three ribs, while Cardassians had at least seven ribs. (TNG: "Ethics"; DS9: "The Way of the Warrior")
At least one possibly apocryphal image depicts Klingon ribs in a roughly hexagonal honeycomb arrangement. The image also suggests that they actually have 23 small ribs on each side.
During a fight with A.G. Robinson at the 602 Club in 2143, Jonathan Archer had two ribs bruised. (ENT: "First Flight")
After Benjamin Sisko challenged Solok to a wrestling match when he was a cadet, the Vulcan cracked two of his ribs. (DS9: "Take Me Out to the Holosuite")
Jono broke two ribs when trying to ride a Talarian t'stayan. (TNG: "Suddenly Human")
In 2367, Ishara Yar received a couple of cracked ribs in a conflict with the Coalition on Turkana IV. (TNG: "Legacy")
Soon after, Lieutenant Umbato, a Starfleet officer serving aboard the USS Enterprise-D, broke two ribs during a holodeck exercise. (TNG: "Data's Day")
Kor had a scorcher burn on his fourteenth rib, something which Curzon and Jadzia Dax knew. (DS9: "Blood Oath")
In 2370, Anna claimed Jean-Luc Picard had sustained three broken ribs in the crash of the Iyaaran shuttle, when in fact he hadn't. (TNG: "Liaisons")
Later that year, William T. Riker broke a rib while engaging in bat'leth moves with Worf. (TNG: "The Pegasus")
Drex and several other Klingons broke seven of Elim Garak's transverse ribs in early 2372. (DS9: "The Way of the Warrior")
Late that year, Keiko O'Brien suffered broken ribs when she was thrown against the bulkhead of the USS Volga. (DS9: "Body Parts")
After having sex with Grilka in early 2373, Quark had a compound fracture of the right radius, two fractured ribs, torn ligaments, strained tendons and several bruises, contusions and scratches. (DS9: "Looking for par'Mach in All the Wrong Places")
Soon after, it was noted that Jadzia Dax had recently been treated for seven muscle pulls, two contusions and three cracked ribs due to her interspecies romance with Worf. (DS9: "Let He Who Is Without Sin...")
Later, Kathryn Janeway bruised two ribs after being attacked by a macrovirus. (VOY: "Macrocosm")
Worf broke "three or four" of his ribs in a fight with Ikat'ika later in 2373. Julian Bashir wanted him to quit, but Worf and Martok were insistent he continue to fight the Jem'Hadar. (DS9: "By Inferno's Light")
Later that year, B'Elanna Torres sustained several broken ribs when a plasma conduit exploded during a battle with the Nerada. (VOY: "Favorite Son")
Soon after, a couple of Garak's ribs were broken when Miles O'Brien incapacitated him by detonating a phaser. (DS9: "Empok Nor")
In 2374, Grathon Tolar stabbed Quark but the Ferengi's ribs deflected the knife from any major organs. (DS9: "In the Pale Moonlight")
In 2375, Tuvok received three fractured ribs after being assaulted by members of Yost's species. (VOY: "Gravity")
Later that year, Joran Dax said he'd "love to slip a knife between [Quark's] ribs." (DS9: "Field of Fire")
In the jack-in-the-box-affected Bashir 62 holoprogram, Tony Cicci bruised three of Vic Fontaine's ribs. (DS9: "Badda-Bing, Badda-Bang")