Scaphoid bone: Difference between revisions

| Name = scaphoidScaphoid bone

| Latin = Osos scaphoideum, <br>os naviculare manus

| Articulations = articulatesArticulates with five bones<br>[[radius (bone)|radius]] proximally<br>[[trapezoid bone]] and [[trapezium bone]] distally<br>[[capitate]] and [[lunate bone|lunate]] medially

The palmar surface of the scaphoid is concave, and forming a distal [[tubercle]], giving attachment to the [[Flexor retinaculum of the hand|transverse carpal ligament]]. The proximal surface is triangular, smooth and convex, and articulates with the [[radius (bone)|radius]] and adjacent carpal bones, namely the lunate, capitate, trapezium and trapezioid.<ref name=EATHORNE2005>{{cite journal |last vauthors = Eathorne|first= SW | title = The wrist: clinical anatomy and physical examination--an update. | journal = Primary care|date=MarCare 2005| volume = 32 | issue = 1 | pages = 17–33 | date = March 2005 | pmid = 15831311 | doi = 10.1016/j.pop.2004.11.009 }}</ref> The lateral surface is narrow and gives attachment to the [[radial collateral ligament (wrist)|radial collateral ligament]]. The medial surface has two facets, a flattened semi-lunar facet articulating with the lunate bone, and an inferior concave facet, articulating alongside the lunate with the head of the capitate bone.<ref name="Gray-6b1-4" />

The dorsal surface of the bone is narrow, with a groove running the length of the bone and allowing ligaments[[ligament]]s to attach, and the surface facing the fingers (anatomically inferior) is smooth and convex, also triangular, and divided into two parts by a slight ridge.<ref name="Gray-6b1-4" />

It receives its blood supply primarily from lateral and distal branches of the [[radial artery]], via palmar and dorsal branches. These provide an "abundant" supply to middle and distal portions of the bone, but neglectsneglect the proximal portion, which relies on [[:wikt:retrograde|retrograde]] flow.<ref name=BEASLEY2003 /> {{rp|189}} The dorsal branch supplies the majority of the middle and distal portions, with the palmar branch supplying only the distal third of the bone.<ref name=EATHORNE2005 />

The dorsal blood supply, particularly of the proximal portion, is highly variable.<ref name=BEASLEY2003 /> {{rp|189}} Sometimes the fibers of the [[abductor pollicis brevis]] emerge from the tubercle.<ref name="Gray-6b1-4" />

In reptiles, birds, and amphibians, thisthe bonescaphoid is instead commonly referred to as the '''''radiale''''' because of its articulation with the [[radius (bone)|radius]].

== Function ==

The carpal bones function as a unit to provide a bony superstructure for the [[hand]].<ref name=GRAYS2005>{{cite book|lastlast1=Drake|firstfirst1=Richard L.|title=Gray's anatomy for students|year=2005|publisher=Elsevier/Churchill Livingstone|location=Philadelphia|isbn=978-0-8089-2306-0|author2last2=Vogl, |first2=Wayne |author3last3=Tibbitts,Mitchell |first3=Adam W.M. Mitchell| name-list-style = vanc |author4others=illustrationsIllustrated by Richard Tibbitts and Paul Richardson |author5oclc=646533128 Richardson,}}</ref>{{rp|708}} PaulThe scaphoid is also involved in movement of the wrist.<ref name=BEASLEY2003 />{{rp|6}} It, along with the [[lunate]], articulates with the [[Radius (bone)|radius]] and [[ulna]] to form the major bones involved in movement of the wrist.<ref name=GRAYS2005 /> The scaphoid serves as a link between the two rows of carpal bones. With wrist movement, the scaphoid may flex from its position in the same plane as the forearm to perpendicular.<ref name=BEASLEY2003 />{{rp|176–177}}

[[Scaphoid fracture|Fractures of the scaphoid]] are the most common of the carpal bone injuries, because of its connections with the two rows of carpal bones.<ref name=BEASLEY2003 /> {{rp|177}}

The scaphoid can be slow to heal because of the limited circulation to the [[bone]]. Fractures of the scaphoid must be recognized and treated quickly, as prompt treatment by immobilization or surgical fixation increases the likelihood of the bone healing in anatomic alignment, thus avoiding mal-union or non-union.<ref name=":0">{{cite journal | vauthors = Wijetunga AR, Tsang VH, Giuffre B | title = The utility of cross-sectional imaging in the management of suspected scaphoid fractures | journal = Journal of Medical Radiation Sciences | volume = 66 | issue = 1 | pages = 30–37 | date = March 2019 | pmid = 30160062 | pmc = 6399186 | doi = 10.1002/jmrs.302 }}</ref> Delays may compromise healing. Failure of the fracture to heal ("non-union") will lead to post-traumatic [[osteoarthritis]] of the carpus.<ref name=BEASLEY2003 /> {{rp|189}} One reason for this is because of the "tenuous" blood supply to the proximal segment.<ref name=EATHORNE2005 /> Even rapidly immobilized fractures may require surgical treatment, including use of a headless compression screw such as the [[Herbert screw]] to bind the two halves together.

A condition called [[scapholunate instability]] can occur when the [[scapholunate ligament]] (connecting the scaphoid to the [[lunate bone]]) and other surrounding ligaments are disrupted. In this state, the distance between the scaphoid and [[lunate]] bones is increased.<ref name=BEASLEY2003 /> {{rp|180}}

There is aOne rare disease of thisthe bonescaphoid is called [[Preiser disease|Preiser's Disease]].

==HistoryEtymology==

The etymology of theword ''scaphoid bone'' ({{Lang-el|σκαφοειδές}}) is derived from the Greek ''skaphos,'', which means "a boat,", and the Greek ''eidos,'', which means "kind".<ref>{{cite book |last1=Anderson |first1=Kenneth |last2=Anderson |first2=Lois E. |last3=Glanze |first3=Walter D. | name-list-style = vanc |title=[[Mosby's Medical, Nursing & Allied Health Dictionary]], Fourth|edition=4th Edition,|date=1994 |page=1396 |publisher=Mosby-Year Book|location=St. 1994,Louis p.|isbn=978-0-8016-7225-5 1396|oclc=461378724 }}</ref> The name refers to the shape of the bone, supposedly reminiscent of a boat. In older literature about [[human anatomy]],<ref name="Gray-6b1-4">{{cite webbook | last = Gray | first = Henry | name-list-style = vanc | url = http://www.bartleby.com/107/ | section-url = http://www.bartleby.com/107/54.html | title = Anatomy of the Human Body | section = 6b. The Hand. 1. The Carpus | at = [http://www.bartleby.com/107/54.html#4 4] | year = 1918 | via = Bartleby.com }}</ref> the scaphoid is referred to as the navicular bone of the hand (this time from the Latin ''navis'' for boat); there is also [[navicular bone|a bone in a similar position in the foot]], which is called the navicular. The modern term for the bone in the hand is ''scaphoid''; in human anatomy the term ''navicular'' is reserved for the bone in the foot.

File:Slide5kakaDissection of the human hand - 01 - Scaphoidscaphoid bone.png|Wrist joint. Deep dissection. Posterior view.

== See alsoReferences ==

{{Anatomy-termsReflist}}

[[Category:CarpusCarpal bones]]