Hamate bone explained

Hamate bone
Latin:os hamatum
Articulations:Articulates with five bones:
the lunate proximally
the fourth and fifth metacarpals distally
the triangular medially
the capitate laterally

The hamate bone (from Latin hamatus, "hooked"), or unciform bone (from Latin uncus, "hook"), Latin os hamatum and occasionally abbreviated as just hamatum,[1] [2] [3] is a bone in the human wrist readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its palmar surface.

Structure

The hamate is an irregularly shaped carpal bone found within the hand. The hamate is found within the distal row of carpal bones, and abuts the metacarpals of the little finger and ring finger.[4]

Adjacent to the hamate on the ulnar side, and slightly above it, is the pisiform bone. Adjacent on the radial side is the capitate, and proximal is the lunate bone.

Surfaces

The hamate bone has six surfaces:

Hook

The hook of hamate (la|hamulus) is found at the proximal, 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 carpal tunnel, and the radial border for Guyon's canal. Numerous structures attach to it, including ligaments from the pisiform, the transverse carpal ligament, and the tendon of flexor carpi ulnaris.

Its medial surface to the flexor digiti minimi brevis and 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.

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.

Clinical significance

The hamate bone is the bone most commonly fractured when a golfer hits the ground hard with a golf club on the downswing or a hockey player hits the ice with a slap shot. The fracture is usually a 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.

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).

Etymology

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

See also

Notes and References

  1. Gdoura. F.. Trigui. M.. Ellouze. Z.. Hamed. Y. B.. Ayadi. K.. Keskes. H.. October 2010. Hamatum osteoblastoma. Orthopaedics & Traumatology, Surgery & Research . 96. 6. 712–716. 10.1016/j.otsr.2010.02.014. 1877-0568. 20692218. free.
  2. Mei. Guo-Hua. Wang. Hai-Ming. Fan. Cun-Yi. Zhang. Chang-Qing. Zeng. Bing-Fang. October 2014. Possibility of the hamatum carpometacarpal joint as a new joint donor site for interphalangeal joint restoration. European Journal of Orthopaedic Surgery & Traumatology: Orthopedie Traumatologie. 24. 7. 1175–1180. 10.1007/s00590-013-1300-4. 1633-8065. 23982116. 25697262 .
  3. Alp. Nazmi Bülent. Kaleli. Tufan. Kalay. Onur Can. Karpat. Fatih. Akdag. Gokhan. Macunluoglu. Aslı Ceren. Oral. Gamze Saygı. 2020. The Effect of Hamatum Curvature Angle on Carpal Tunnel Volumetry: A Mathematical Simulation Model. Computational and Mathematical Methods in Medicine. 2020. 7582181. 10.1155/2020/7582181. 1748-6718. 7312712. 32617118. free .
  4. Book: Drake, Richard L.. Gray's anatomy for students. 2005. Elsevier/Churchill Livingstone. Philadelphia. 978-0-8089-2306-0. Vogl, Wayne . Tibbitts, Adam W.M. Mitchell . illustrations by Richard . Richardson, Paul .
  5. Eathorne. SW. The wrist: clinical anatomy and physical examination—an update.. Primary Care. March 2005. 32. 1. 17–33. 15831311. 10.1016/j.pop.2004.11.009.
  6. Balachandran. Ajay. Kartha. Moumitha. Krishna. Anooj. Thomas. Jerry. K. Prathilash. TN. Prem. GK. Libu. B. Krishnan. John. Liza. A Study of Ossification of Capitate, Hamate, Triquetral & Lunate in Forensic Age Estimation. Indian Journal of Forensic Medicine & Toxicology. 2014. 8. 2. 218–224. 10.5958/0973-9130.2014.00720.8. 18 August 2014. 0973-9130. subscription.
  7. News: Chris . Snow . Peña to have surgery . The Boston Globe . June 1, 2006 . September 2, 2011.
  8. Web site: John . Manuel . Wrist Troubles Drain Prospects' Power . Baseball America . March 31, 2004 . September 2, 2011.
  9. News: Amalie . Benjamin . He's gaining in arms race . The Boston Globe . July 27, 2007 . September 2, 2011.
  10. News: Associated Press . Dickerson has hand, wrist surgery . ESPN . May 3, 2010 . September 2, 2011.
  11. Web site: Kieran . Carobine . Domonic Brown's Surgery A Success . Phillies Nation . March 8, 2011 . September 2, 2011.
  12. Web site: Angels' Mike Trout: Undergoes hamate surgery . July 5, 2023 . CBS Sports . 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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