The '''hamate bone''' or '''unciform bone''' (from [[Latin language|Latin]] ''[[wikt:uncus|uncus]]'', "hook") is a bone in the human [[wrist]] readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its [[Radioulnar|palmar]] surface.
The '''hamate bone''' (from [[Latin language|Latin]] [[wiktionary:hamatus|hamatus]], "hooked"), or '''unciform bone''' (from [[Latin language|Latin]] ''[[wikt:uncus|uncus]]'', "hook") is a bone in the human [[wrist]] readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its [[Radioulnar|palmar]] surface.
==Structure==
==Structure==
Revisionasof21:04,17September2021
hamate
Hamate bone
Left hand anterior view (palmar view). Hamate bone shown in red.
The hamate bone (from Latinhamatus, "hooked"), or unciform bone (from Latinuncus, "hook") is a bone in the human wrist readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its palmar surface.
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.[1]: 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 (Latin: 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.[2] The ulnar nerve hooks around the hook of hamate as it crosses towards the medial side of hand.
The ossification of the hamate starts between 1 and 12 months.[3] The hamate does not fully ossify until about the 15th year of life.[2]
In 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.[1]: 708
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 pinkie finger with partial involvement of the ring finger 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.[2]
It is also a common injury in baseball players. Several professional baseball players have had the bone removed during the course of their careers.[4][5][6][7][8] This condition has been called "Wilson's Wrist".[9]
The calcification of the unciform 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".
Additional images
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.
Right hand anterior view (palmar view). Thumb on top.
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. Dorsal surface. 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.
Right wrist joint. Deep dissection. Anterior (palmar) view.
See also
Wikimedia Commons has media related to Hamate bone.
^ abcDrake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN978-0-8089-2306-0.
This article incorporates text in the public domain from page 227 of the 20th edition of Gray's Anatomy (1918)
