Metacarpal bones

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Metacarpal bones_table_infobox_0

Metacarpal bonesMetacarpal bones_header_cell_0_0_0
DetailsMetacarpal bones_header_cell_0_1_0
OriginsMetacarpal bones_header_cell_0_2_0 Carpal bones of wristMetacarpal bones_cell_0_2_1
InsertionsMetacarpal bones_header_cell_0_3_0 Proximal phalangesMetacarpal bones_cell_0_3_1
ArticulationsMetacarpal bones_header_cell_0_4_0 Carpometacarpal, intermetacarpal, metacarpophalangealMetacarpal bones_cell_0_4_1
IdentifiersMetacarpal bones_header_cell_0_5_0
LatinMetacarpal bones_header_cell_0_6_0 os metacarpale

pl. ossa metacarpaliaMetacarpal bones_cell_0_6_1

MeSHMetacarpal bones_header_cell_0_7_0 Metacarpal bones_cell_0_7_1
TA98Metacarpal bones_header_cell_0_8_0 Metacarpal bones_cell_0_8_1
TA2Metacarpal bones_header_cell_0_9_0 Metacarpal bones_cell_0_9_1
FMAMetacarpal bones_header_cell_0_10_0 Metacarpal bones_cell_0_10_1

In human anatomy, the metacarpal bones or metacarpus, form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist which forms the connection to the forearm. Metacarpal bones_sentence_0

The metacarpal bones are analogous to the metatarsal bones in the foot. Metacarpal bones_sentence_1

Structure Metacarpal bones_section_0

The metacarpals form a transverse arch to which the rigid row of distal carpal bones are fixed. Metacarpal bones_sentence_2

The peripheral metacarpals (those of the thumb and little finger) form the sides of the cup of the palmar gutter and as they are brought together they deepen this concavity. Metacarpal bones_sentence_3

The index metacarpal is the most firmly fixed, while the thumb metacarpal articulates with the trapezium and acts independently from the others. Metacarpal bones_sentence_4

The middle metacarpals are tightly united to the carpus by intrinsic interlocking bone elements at their bases. Metacarpal bones_sentence_5

The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-independent. Metacarpal bones_sentence_6

Each metacarpal bone consists of a body or shaft, and two extremities: the head at the distal or digital end (near the fingers), and the base at the proximal or carpal end (close to the wrist). Metacarpal bones_sentence_7

Body Metacarpal bones_section_1

The body (shaft) is prismoid in form, and curved, so as to be convex in the longitudinal direction behind, concave in front. Metacarpal bones_sentence_8

It presents three surfaces: medial, lateral, and dorsal. Metacarpal bones_sentence_9

Metacarpal bones_unordered_list_0

  • The medial and lateral surfaces are concave, for the attachment of the interosseus muscles, and separated from one another by a prominent anterior ridge.Metacarpal bones_item_0_0
  • The dorsal surface presents in its distal two-thirds a smooth, triangular, flattened area which is covered in by the tendons of the extensor muscles. This surface is bounded by two lines, which commence in small tubercles situated on either side of the digital extremity, and, passing upward, converge and meet some distance above the center of the bone and form a ridge which runs along the rest of the dorsal surface to the carpal extremity. This ridge separates two sloping surfaces for the attachment of the interossei dorsales.Metacarpal bones_item_0_1
  • To the tubercles on the digital extremities are attached the collateral ligaments of the metacarpophalangeal joints.Metacarpal bones_item_0_2

Base Metacarpal bones_section_2

The base (basis) or carpal extremity is of a cuboidal form, and broader behind than in front: it articulates with the carpal bones and with the adjoining metacarpal bones; its dorsal and volar surfaces are rough, for the attachment of ligaments. Metacarpal bones_sentence_10

Head Metacarpal bones_section_3

The head (caput) or digital extremity presents an oblong surface markedly convex from before backward, less so transversely, and flattened from side to side; it articulates with the proximal phalanx. Metacarpal bones_sentence_11

It is broader, and extends farther upward, on the volar than on the dorsal aspect, and is longer in the antero-posterior than in the transverse diameter. Metacarpal bones_sentence_12

On either side of the head is a tubercle for the attachment of the collateral ligament of the metacarpophalangeal joint. Metacarpal bones_sentence_13

The dorsal surface, broad and flat, supports the tendons of the extensor muscles. Metacarpal bones_sentence_14

The volar surface is grooved in the middle line for the passage of the flexor tendons, and marked on either side by an articular eminence continuous with the terminal articular surface. Metacarpal bones_sentence_15

Neck Metacarpal bones_section_4

The neck, or subcapital segment, is the transition zone between the body and the head. Metacarpal bones_sentence_16

Articulations Metacarpal bones_section_5

Besides the metacarpophalangeal joints, the metacarpal bones articulate by carpometacarpal joints as follows: Metacarpal bones_sentence_17

Metacarpal bones_ordered_list_1

  1. the first with the trapezium;Metacarpal bones_item_1_3
  2. the second with the trapezium, trapezoid, capitate and third metacarpal;Metacarpal bones_item_1_4
  3. the third with the capitate and second and fourth metacarpals;Metacarpal bones_item_1_5
  4. the fourth with the capitate, hamate, and third and fifth metacarpals;Metacarpal bones_item_1_6
  5. and the fifth with the hamate and fourth metacarpal;Metacarpal bones_item_1_7

Metacarpal bones_unordered_list_2

  • Metacarpal bones_item_2_8
  • Metacarpal bones_item_2_9

Insertions Metacarpal bones_section_6

Extensor Carpi Radialis Longus/Brevis: Both insert on the base of metacarpal II; Assist with wrist extension and radial flexion of the wrist Metacarpal bones_sentence_18

Extensor Carpi Ulnaris: Inserts on the base of metacarpal V; Extends and fixes wrist when digits are being flexed; assists with ulnar flexion of wrist Metacarpal bones_sentence_19

Abductor Pollicis Longus: Inserts on the trapezium and base of metacarpal I; Abducts thumb in frontal plane; extends thumb at carpometacarpal joint Metacarpal bones_sentence_20

Opponens Pollicis: Inserts on metacarpal I; flexes metacarpal I to oppose the thumb to the fingertips Metacarpal bones_sentence_21

Opponens digiti minimi: Inserts on the medial surface of metacarpal V; Flexes metacarpal V at carpometacarpal joint when little finger is moved into opposition with tip of thumb; deepens palm of hand. Metacarpal bones_sentence_22

Metacarpal bones_unordered_list_3

  • Metacarpal bones_item_3_10
  • Metacarpal bones_item_3_11

Clinical significance Metacarpal bones_section_7

Congenital disorders Metacarpal bones_section_8

The fourth and fifth metacarpal bones are commonly "blunted" or shortened, in pseudohypoparathyroidism and pseudopseudohypoparathyroidism. Metacarpal bones_sentence_23

A blunted fourth metacarpal, with normal fifth metacarpal, can signify Turner syndrome. Metacarpal bones_sentence_24

Blunted metacarpals (particularly the fourth metacarpal) are a symptom of Nevoid basal cell carcinoma syndrome. Metacarpal bones_sentence_25

Fracture Metacarpal bones_section_9

The neck of a metacarpal is a common location for a boxer's fracture. Metacarpal bones_sentence_26

Other animals Metacarpal bones_section_10

In four-legged animals, the metacarpals form part of the forefeet, and are frequently reduced in number, appropriate to the number of toes. Metacarpal bones_sentence_27

In digitigrade and unguligrade animals, the metacarpals are greatly extended and strengthened, forming an additional segment to the limb, a feature that typically enhances the animal's speed. Metacarpal bones_sentence_28

In both birds and bats, the metacarpals form part of the wing. Metacarpal bones_sentence_29

History Metacarpal bones_section_11

Etymology Metacarpal bones_section_12

The Greek physician Galen used to refer to the metacarpus as μετακάρπιον. Metacarpal bones_sentence_30

The Latin form metacarpium more truly resembles its Ancient Greek predecessor μετακάρπιον than metacarpus. Metacarpal bones_sentence_31

Meta– is Greek for beyond and carpal from Ancient Greek καρπός (karpós, “wrist”). Metacarpal bones_sentence_32

In anatomic Latin, adjectives like metacarpius, metacarpicus, metacarpiaeus, metacarpeus, metacarpianus and metacarpalis can be found. Metacarpal bones_sentence_33

The form metacarpius is more true to the later Greek form μετακάρπιος. Metacarpal bones_sentence_34

Metacarpalis, as in ossa metacarpalia in the current official Latin nomenclature, Terminologia Anatomica is a compound consisting of Latin and Greek parts. Metacarpal bones_sentence_35

The usage of such hybrids in anatomic Latin is disapproved by some. Metacarpal bones_sentence_36

Additional images Metacarpal bones_section_13

Metacarpal bones_unordered_list_4

  • Metacarpal bones_item_4_12
  • Metacarpal bones_item_4_13
  • Metacarpal bones_item_4_14
  • Metacarpal bones_item_4_15
  • Metacarpal bones_item_4_16
  • Metacarpal bones_item_4_17
  • Metacarpal bones_item_4_18

See also Metacarpal bones_section_14

This article uses anatomical terminology. Metacarpal bones_sentence_37

Metacarpal bones_unordered_list_5

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: bones.