- This article is about Carpal bones. In Greek mythology, Carpus (Greek: Karpos, "fruit") was a son of Chloris and Zephyrus.
In tetrapods, the carpus is the cluster of bones in the hand between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers, whereas those of the metacarpus do. The joint between the radius and ulna and the carpus is called the wrist. The corresponding part of the foot is the tarsus.
The carpal bones have evolved differently in different animals (for example in some macropods, the scaphoid and lunar bones are fused into the scapholunar bone)*.
The skeleton of the hand 1, 2 is subdivided into three segments:
- the carpus or wrist bones;
- the metacarpus or bones of the palm;
- and the phalanges or bones of the digits.
The Carpus (Ossa Carpi)
The eight carpal bones form two rows (some are now renamed from Latin).
- Those of the proximal row, from the radial to the ulnar side, are:
- Those of the distal row, in the same order, are:
- Trapezium (bone) articulates with the metacarpal of the thumb.
- Trapezoid articulates with the 2nd metacarpal.
- Capitate articulates with the metacarpal of the middle finger.
- Hamate articulates with the metacarpals of the 4th and 5th fingers. It has a projection called a hook.
Mnemonics to remember these:
- Some lovers try positions / that they can't handle.
- Sally left the party / to take Cathy home.
- Students Like The Professor To Teach Complex Hypotheses
- She Likes Taking Prostitutes To The Calley Hotel
- She Looks Too Pretty Try To Catch Her
- Stop Letting Those People Touch The Cadaver's Hands
A Hindi version which is quite funny and hence popular among students in India, is:
- Sneh Lata Tinde Paka Tere Tinde Catchey Hain
which can be roughly translated as an exhortation to a woman called Sneh Lata, asking her to properly cook a vegetable!
Common characteristics of the carpal bones
Carpus.png|thumb|500px|
BONES OF HAND
Proximal: A=
Scaphoid, B=
Lunate, C=
Triquetral, D=
Pisiform
Distal: E=
Trapezium, F=
Trapezoid, G=
Capitate, H=
Hamate]]
Each bone (excepting the pisiform) presents six surfaces.
Of these the palmar or anterior and the dorsal or posterior surfaces are rough, for ligamentous attachment; the dorsal surfaces being the broader, except in the navicular and lunate.
The superior or proximal, and inferior or distal surfaces are articular, the superior generally convex, the inferior concave; the medial and lateral surfaces are also articular where they are in contact with contiguous bones, otherwise they are rough and tuberculated.
The structure in all is similar: cancellous tissue enclosed in a layer of compact bone.
Articulations
In humans:
- scaphoid articulates with 5 bones – radius, lunate, capitate, trapezoid, trapezium
- lunate articulates with 5 bones - radius, scaphoid, capitate, hamate, triquetral
- triquetral articulates with 3 bones – pisiform, hamate, lunate
- pisiform articulates only with triquetral, sitting on top of it
- trapezium articulates with 4? bones – thumb metatarsal, scaphoid, trapezoid, index finger metatarsal
- trapezoid articulates with 4 bones – scaphoid, capitate, metatarsal of index finger, trapezium
- capitate articulates with 7 bones – hamate, lunar, scaphoid, trapezoid and index, third and fouth metatarsals
- hamate articulates with 5 bones – triquetral, lunate, capitate, and fourth and fifth metatarsals
See also
External links
Skeletal system | Wrist
Handwurzelknochen | Carpo | Plaštaka | Nadgarstek | Carpo | Handlov