Carpometacarpus
Encyclopedia
The carpometacarpus is the fusion of the carpal and metacarpal bone, essentially a single fused bone between the wrist
and the knuckle
s. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless bird
s, however, its shape may be slightly different, or it might be absent entirely.
It forms the tip of the wing
skeleton in birds. To it, most of the primary remiges attach. The alula
, by contrast, is formed by the thumb
, which does not completely fuse with the other hand-bones. Likewise, the tipmost primaries attach to the phalanx bones.
To non-biologists the carpometacarpus may be best known from buffalo wings
. Buffalo wings come in two basic sizes, a large angled one containing three major bones, and a smaller flat one containing only two. The bone missing in the latter is the carpometacarpus.
Wrist
In human anatomy, the wrist is variously defined as 1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand;...
and the knuckle
Knuckle
The knuckles are the joints of the fingers and toes, which are brought into prominence when the hand is clenched and a fist is made. The word is cognate to similar words in other Germanic languages, such as the Dutch "Knokkel" or German "Knöchel" , i.e., Knöchlein, the diminutive of the German...
s. It is a smallish bone in most birds, generally flattened and with a large hole in the middle. In flightless bird
Flightless bird
Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to have evolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin...
s, however, its shape may be slightly different, or it might be absent entirely.
It forms the tip of the wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
skeleton in birds. To it, most of the primary remiges attach. The alula
Alula
The alula, or bastard wing, is a small projection on the anterior edge of the wing of modern birds. The alula is the freely moving first digit, a bird's "thumb," and is typically covered with three to five small feathers, with the exact number depending on the species...
, by contrast, is formed by the thumb
Thumb
The thumb is the first digit of the hand. When a person is standing in the medical anatomical position , the thumb is the lateral-most digit...
, which does not completely fuse with the other hand-bones. Likewise, the tipmost primaries attach to the phalanx bones.
To non-biologists the carpometacarpus may be best known from buffalo wings
Buffalo wings
A Buffalo wing, hot wing or wing is a chicken wing section that is traditionally fried unbreaded and then coated in sauce...
. Buffalo wings come in two basic sizes, a large angled one containing three major bones, and a smaller flat one containing only two. The bone missing in the latter is the carpometacarpus.