The bones of the hand include the bones of the wrist (ossa carpi), metacarpal bones (ossa metacarpi) and the bones of the fingers, or phalanges (phalanges/ossa digitorum).

All of them are connected to each other with various joints. Let’s start with the carpal joints.

The first is the midcarpal joint (articulatio mediocarpalis). Essentially it is not a single, but several joints that are formed between the proximal and distal rows of the wrist bones.

The joint gap is S-shaped. The joint has two compartments of sorts. One of them is formed by the navicular bone, which articulates with the trapezium bone and trapezoid bone. The other compartment consists of the capitate and hamate bones, which are connected to the triquetrum, lunate and navicular bones.

The articular capsule is relatively loose and very thin on the dorsal side, it inserts along the edge of the articular surfaces.

According to the classification, the joint is simple, hinge, uniaxial, and combined (with the radiocarpal joint (articulatio radiocarpea))

Almost no motions take place in this joint.

The ligamentous apparatus of this joint, as well as other wrist joints, contains several ligaments.

• The palmar and dorsal intercarpal ligaments (ligamenta intercarpalia palmaria et dorsalia)

  

  

• The radiate carpal ligament (ligamentum carpi radiatum)

  

  

• The intra-articular interosseous intercarpal ligaments (ligamenta intercarpalia interossea intraarticularia)

  

• The radial collateral ligament of the wrist joint (ligamentum collaterale carpi radiale)

  

  

  

• The ulnar collateral ligament of wrist joint (ligamentum collaterale carpi ulnare)

  

  

  

• The pisohamate ligament (ligamentum pisohamatum)

  

  

• The pisometacarpal ligament (ligamentum pisometacarpale)

  

  

  Next, let’s learn about the intercarpal joints (articulationes intercarpales). They are formed between the articular surfaces of the carpal bones facing each other.

  

  These are triquetrum bone (os triquetrum), lunate bone (os lunatum), scaphoid bone (os scaphoideum), trapezium bone (os trapezium), trapezoid bone (os trapezoideum), capitate bone (os capitatum), hamate bone (os hamatum) and pisiform bone (os pisiforme).

  The capsules of this joints are thin, they insert along the edges of the articular surfaces.

  The joint cavities of the midcarpal and intercarpal joints communicate with each other.

  According to the classification, the joint is simple and plane. Almost no motions take place in this joint.

  Let’s move on to the carpometacarpal joints (articulationes carpometacarpales).

  

  

  These joints are formed between the distal articular surfaces of the second row of wrist bones and articular surfaces on the bases of the 2nd-5th metacarpals.

  The articular capsule is thin, common to all four carpometacarpal joints, and stretched tightly.

  

  The joint gap is also common, it is an angled line that connects to the cavities of the intercarpal and midcarpal joints.

  According to the classification, carpometacarpal joints are simple and plane, there are practically no motions in them.

  The fixing apparatus of the joint is composed of several ligaments:

• The palmar carpometacarpal ligaments (ligamenta carpometacarpalia palmaria) are located on the palmar surface of the hand

  

• The dorsal carpometacarpal ligaments (ligamenta carpometacarpalia dorsalia) are located on the back surface of the hand.

  

  Let’s learn about the carpometacarpal joint of the thumb (articulatio carpometacarpalis pollicis).

  

  The articular surfaces involved in the formation of the joint are the articular surface of the trapezium bone and the articular surface of the base of the first metacarpal bone.

  The joint capsule is loose, thin.

  According to the classification, the joint is simple, saddle-shaped, and not combined.

  

  

  

  The following range of motions is possible in the joint:

• Around the frontal axis: flexion and extension. Since the frontal axis is located at an angle with respect to the frontal plane, the thumb tilts towards the palm during flexion, it is opposed to the rest of the fingers.

• Around the sagittal axis, the thumb is adducted (adductio) to the index finger (index).

• With a combination of movements around the frontal and sagittal axes, circumduction takes place.

  Let’s move on to the intermetacarpal joints (articulationes intermetacarpales).

  

  The articular surfaces involved in the formation of the joint are the adjacent articular surfaces of the bases of the 2nd- 5th metacarpals.

  The joint capsules are common with the capsule of the carpometacarpal joints.

  The ligamentous apparatus of the joint includes the palmar and dorsal metacarpal ligaments (ligamenta metacarpalia palmaria et dorsalia)

  

  

  

  Next come the metacarpophalangeal joints (articulationes metacarpophalangeae).

  They are formed between the articular surfaces on the base of the proximal phalanx (phalanx proximalis) and the corresponding head of the metacarpal bone (os metacarpale).

  

  

  The joint capsule is loose, attached along the edges of the articular surfaces.

  According to the classification, the joint is condylar, ellipsoid, biaxial and not combined.

  The following range of motions is possible in the joint:

• around the frontal axis: flexion and extension

• around the sagittal axis: abduction and adductio

• Circular motion takes place with a shift from one axis to another.

  The fixing apparatus of the joint is composed of several ligaments:

• The lateral collateral ligaments (ligamenta collateralia) fix the joints along the lateral surfaces.

  

  

• The palmar ligaments (ligamenta palmaria) fix joints on the palmar surface.

  

• The deep transverse metacarpal ligaments (ligamenta metacarpalia transversa profunda) are stretched between the heads of the 2nd-5th metacarpals.

  

  And the last joints of the hand are the interphalangeal joints (articulationes interphalangeae manus)

  They are formed between the articular surfaces on the corresponding bases and the heads of the phalanges.

  The joint capsule is attached along the edge of the articular surfaces.

  

  

  According to the classification, the joint is simple, hinge, uniaxial and not combined.

  In the joint, flexion and extension motions around the frontal axis take place.

  The fixing apparatus of the joint is composed of several ligaments:

• The lateral collateral ligaments (ligamenta collateralia) fix the joints along the lateral surfaces.

  

  

• The palmar ligaments (ligamenta palmaria) fix the joints on the palmar surface.

  

  The following vessels and nerves take part in the blood supply and innervation of the hand joints.

• Arteries: branches of the deep arterial arch of the hand, branches of the palmar and dorsal plexuses of the hand

• Veins: veins of the same name

• Nerves: branches of the ulnar, median, and radial nerves

Dictionary

Joints of the wrist

Midcarpal joint

art. mediocarpalis

Triquetrum bone

os triquetrum

Lunate bone

os lunatum

Scaphoid bone

os scaphoideum

Trapezium bone

os trapezium

Trapezoid bone

os trapezoideum

Capitate bone

os capitatum

Hamate bone

os hamatum

Wrist joint

art. radiocarpea

Intercarpal joints

art. intercarpales

Pisiform bone

os pisiforme

Palmar and dorsal intercarpal ligaments

ligg. intercarpalia palmaria et dorsalia

Radiate carpal ligament

lig. carpi radiatum

Interosseous intercarpal ligaments

ligg. intercarpalia interossea

Pisohamate ligament

lig. pisohamatum

Pisometacarpal ligament

lig. pisometacarpale

Carpometacarpal joints of the fingers 2-5

artt. carpometacarpales II-V

Metacarpal bones 2-5

ossa metacarpalia II-V

Palmar carpometacarpal ligaments

ligg. carpometacarpalia palmaria

Dorsal carpometacarpal ligaments

ligg. carpometacarpalia dorsalia

1st metacarpal bone

os metacarpale I

Index finger

index

Intermetacarpal joints

artt. intermetacarpales

Palmar and dorsal metacarpal ligaments

ligg. metacarpalia palmaria et dorsalia

Wrist joint

art. manus

Metacarpophalangeal joints

art. metacarpophalangeae

Proximal phalanx

phalanx proximalis

Metacarpal bone

os metacarpale

Collateral ligaments

ligg. collateralia

Palmar ligaments

ligg. palmaria

Deep transverse metacarpal ligaments

ligg. metacarpalia transversa profunda

Interphalangeal joints

artt.interphalangeaephalanges

Phalanges of the fingers

phalanges

Dorsal carpal arch

rete carpale dorsale

Deep palmar arch

arcus palmaris profundus

Superficial palmar arch

arcus palmaris superficialis

Ulnar nerve

n. ulnaris

Median nerve

n. medianus