Hamate bone

Source: Wikipedia, the free encyclopedia.
"Hamatum" redirects here. For its use in taxonomy, see List of Latin and Greek words commonly used in systematic names.
Hamate bone
capitate laterally
Identifiers
Latinos hamatum
MeSHD051225
TA98A02.4.08.012
TA21259
FMA23730
Anatomical terms of bone]

The hamate bone (from

palmar
surface.

Structure

The hamate is an irregularly shaped

metacarpals of the little finger and ring finger.[4]
: 708–709 

Adjacent to the hamate on the ulnar side, and slightly proximal and ulnar to it, is the

capitate, and proximal is the lunate bone.[4]
: 708–709 

Surfaces

The hamate bone has six surfaces:

  • The superior, the apex of the wedge, is narrow, convex, smooth, and articulates with the lunate.
  • The inferior articulates with the fourth and fifth metacarpal bones, by concave facets which are separated by a ridge.
  • The dorsal is triangular and rough for ligamentous attachment.
  • The palmar presents, at its lower and ulnar side, a curved, hook-like process, the
    hamulus
    , directed forward and laterally.
  • The medial articulates with the
    triangular bone
    by an oblong facet, cut obliquely from above, downward and medialward.
  • The lateral articulates with the
    capitate
    by its upper and posterior part, the remaining portion being rough, for the attachment of ligaments.

Hook

Hamate bone of the left hand. Hamulus shown in red.

The hook of hamate (

ulnar side of the hamate bone. The hook is a curved, hook-like process that projects 1–2 mm distally and radially.[5] The ulnar nerve
hooks around the hook of hamate as it crosses towards the medial side of hand.

The hook forms the ulnar border of the

flexor carpi ulnaris.[5]

Its medial surface to the

opponens digiti minimi; its lateral side is grooved for the passage of the flexor tendons
into the palm of the hand.

Development

The ossification of the hamate starts between 1 and 12 months.[6] The hamate does not fully ossify until about the 15th year of life.[5]

Other animals

The bone is also found in many other mammals, and is homologous with the "fourth distal carpal" of reptiles and amphibians.

Function

The carpal bones function as a unit to provide a bony superstructure for the hand.[4]: 708 

Clinical significance

The hamate bone is the bone most commonly

hairline fracture, commonly missed on normal X-rays. Symptoms are pain aggravated by gripping, tenderness over the hamate and symptoms of irritation of the ulnar nerve
. This is characterized by numbness and weakness of the fifth digit with partial involvement of the fourth digit as well, the "ulnar 1½ fingers".

The hook of hamate is particularly prone to fracture-related complications such as non-union due to its tenuous blood supply.[5]

It is also a common injury in baseball players. Several professional baseball players have had the bone removed during the course of their careers.[7][8][9][10][11][12] This condition has been called "Wilson's Wrist".[13]

The calcification of the hamate bone is seen on X-rays during puberty and is sometimes used in orthodontics to determine if an adolescent patient is suitable for orthognathic intervention (i.e. before or at their growth spurt).[citation needed]

Etymology

The etymology derives from the Latin hamatus "hooked," from hamus which means "hook".

Additional images

  • Position of hamate bone (shown in red). Left hand. Animation.
    Position of hamate bone (shown in red). Left hand. Animation.
  • Hamate bone of the left hand. The hook-like process is called hamulus.
    Hamate bone of the left hand. The hook-like process is called
    hamulus
    .
  • Hamate bone.
    Hamate bone.
  • Right hand anterior view (palmar view). Thumb on top.
    Right hand anterior view (palmar view). Thumb on top.
  • Right hand posterior view (dorsal view). Thumb on bottom.
    Right hand posterior view (dorsal view). Thumb on bottom.
  • Bones of the left hand. Palmar surface. Hamate shown in yellow.
    Bones of the left hand. Palmar surface. Hamate shown in yellow.
  • Bones of the left hand. Dorsal surface. Hamate shown in yellow.
    Bones of the left hand. Dorsal surface. Hamate shown in yellow.
  • Transverse section across the wrist and digits. Hamate shown in yellow.
    Transverse section across the wrist and digits. Hamate shown in yellow.
  • Cross section of wrist (thumb on left). Hamate shown in red.
    Cross section of wrist (thumb on left). Hamate shown in red.
  • Right wrist joint. Deep dissection. Anterior (palmar) view.
    Right wrist joint. Deep dissection. Anterior (palmar) view.

See also

Wikimedia Commons has media related to Hamate bone.
This article uses anatomical terminology.

References

Public domain This article incorporates text in the public domain from page 227 of the 20th edition of Gray's Anatomy (1918)

  1. PMID 20692218
    .
  2. S2CID 25697262
    .
  3. PMID 32617118
    .
  4. ^
    ISBN 978-0-8089-2306-0
    .
  5. ^
    PMID 15831311
    .
  6. ISSN 0973-9130
    . Retrieved 18 August 2014.
  7. ^ Snow, Chris (June 1, 2006). "Peña to have surgery". The Boston Globe. Retrieved September 2, 2011.
  8. ^ Manuel, John (March 31, 2004). "Wrist Troubles Drain Prospects' Power". Baseball America. Retrieved September 2, 2011.
  9. ^ Benjamin, Amalie (July 27, 2007). "He's gaining in arms race". The Boston Globe. Retrieved September 2, 2011.
  10. ^ "Dickerson has hand, wrist surgery". ESPN. Associated Press. May 3, 2010. Retrieved September 2, 2011.
  11. ^ Carobine, Kieran (March 8, 2011). "Domonic Brown's Surgery A Success". Phillies Nation. Retrieved September 2, 2011.
  12. ^ "Angels' Mike Trout: Undergoes hamate surgery". CBS Sports. July 5, 2023. Retrieved August 4, 2023.
  13. ^ WILSON JN. Profiles of the carpal canal. J Bone Joint Surg Am. 1954 Jan;36-A(1):127–132
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