Upper limb

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4 Upper limb

Chapter contents

Humerus

Fractures

Radius

Ulna

Fractures

Hand

Carpal bones
Metacarpal bones
Phalanges
Fractures

Elbow joint

Trauma

Wrist joint

Trauma

First carpometacarpal joint

Fractures

Humerus (Figs 4.1 and 4.2)

Type

Long bone.

image

Fig. 4.1 Right humerus (anterior aspect).

A–Lesser tuberosity (tubercle)

B–Greater tuberosity (tubercle)

C–Intertubercular sulcus (bicipital groove)

D–Deltoid tuberosity

E–Lateral border

F–Lateral supracondylar ridge

G–Lateral epicondyle

H–Radial fossa

I–Capitulum

J–Trochlea

K–Medial epicondyle

L–Coronoid fossa

M–Medial supracondylar ridge

N–Surgical neck

O–Anatomical neck

P–Head of humerus.

image

Fig. 4.2 Right humerus (posterior aspect).

1 – Head of humerus

2 – Anatomical neck

3 – Surgical neck

4 – Medial border

5 – Medial supracondylar ridge

6 – Olecranon fossa

7 – Medial epicondyle

8 – Groove for the ulnar nerve

9 – Trochlea

10 – Lateral epicondyle

11 – Lateral supracondylar ridge

12 – Spiral groove

13 – Greater tuberosity (tubercle).

Position

Largest bone in the upper limb.

Articulations

Head of humerus with the glenoid cavity of the scapula to form the shoulder joint.

Trochlea of the humerus with the trochlear notch of the ulna and the capitulum of the humerus with the head of the radius to form the elbow joint.

Main parts

Features of the upper end of the humerus

Head of humerus –

rounded.

Lesser tuberosity (lesser tubercle) –

anteriorly, the tendon of the subscapularis muscle is attached.

Greater tuberosity (greater tubercle) –

postero-laterally the supraspinatus tendon is attached to the upper aspect, infraspinatus tendon to the middle and the teres minor tendon to the lower, posterior aspect.

Intertubercular sulcus (bicipital groove) –

between the tuberosities. Contains the tendon of the long head of biceps.

Anatomical neck –

adjoining the head.

Surgical neck –

between the upper end and the shaft.

Features of the shaft of the humerus

Deltoid tuberosity –

for the attachment of the deltoid muscle, located on the antero-lateral surface.

Spiral groove –

for the radial nerve.

Medial border

Lateral border

Anterior border

Antero-lateral surface

Antero-medial surface –

in the middle of which is the nutrient foramen.

Posterior surface

Features of the lower end of the humerus

Lateral epicondyle –

above the capitulum.

Medial epicondyle –

above the trochlea.

Lateral supracondylar ridge –

distal end of the lateral border above the lateral epicondyle.

Medial supracondylar ridge –

distal end of the medial border above the medial epicondyle.

Capitulum –

rounded; articulates with the head of radius.

Trochlea –

pulley-shaped; articulates with the trochlear notch of the ulna. Has a large medial lip which forms the ‘carrying angle’ (see elbow joint).

Groove for the ulnar nerve –

posterior aspect, medial to the trochlea.

Olecranon fossa –

posteriorly receives the olecranon process of the ulna when the elbow joint is extended.

Coronoid fossa –

anteriorly receives the coronoid process of the ulna when the elbow joint is fully flexed.

Radial fossa –

anteriorly receives the head of the radius when the elbow joint is flexed.

Ossification

Primary centre

Shaft –

8th week of intrauterine life.

Secondary centres

Upper end –

3 centres:

head appears age 6 months;

greater tuberosity age 1–2;

lesser tuberosity age 4–5.

Fuse together age 6.

Fuse with shaft age 18–20.

Lower end –

4 centres:

capitulum appears age 1;

medial epicondyle age 4–6;

trochlea age 9–10;

lateral epicondyle age 12.

Lateral epicondyle, trochlea and capitulum fuse together at puberty.

Fuse with shaft age 14–16.

Medial epicondyle fuses with the shaft age 20.

Radiographic appearances of the humerus (Figs 4.3 and 4.4)

image

Fig. 4.3 Left humerus: anteroposterior projection.

A–Surgical neck

B–Shaft of humerus

C–Medullary cavity

D–Olecranon

E–Medial epicondyle

F–Head of radius

G–Capitulum

H–Lateral epicondyle

I–Olecranon and coronoid fossae

J–Deltoid tuberosity

K–Intertubercular sulcus (Bicipital groove)

L–Lesser tuberosity

M–Greater tuberosity

N–Anatomical neck

O–Head of humerus.

(From Bryan 1996.)

image

Fig. 4.4 Left humerus: lateral projection.

1 – Lesser tuberosity

2 – Intertubercular sulcus (Bicipital groove)

3 – Radius

4 – Ulna

5 – Olecranon

6 – Trochlea

7 – Epicondyles

8 – Supracondylar ridge

9 – Shaft of humerus

10 – Greater tuberosity

11 – Head of humerus.

(From Bryan 1996.)

Fractures

Surgical neck

Cause –

fall on an outstretched hand. Common in elderly people.

Example of treatment –

sling.

Shaft

Usually the middle third.

Spiral

Cause –

fall on the hand with a twisting force.

Example of treatment –

sling.

Transverse

Cause –

fall on the elbow with the arm abducted.

Example of treatment –

manipulation under anaesthesia.

Comminuted –

transverse or short oblique.

Cause –

direct blow on the arm.

Example of treatment –

plaster of Paris either to elbow or axilla to mid-forearm, with the elbow flexed.

Pathological –

proximal half of the shaft.

Cause –

underlying pathology.

Example of treatment –

sling; conservative treatment to alleviate pain.

Supracondylar

Cause –

fall on the hand with elbow flexed. Distal bone fragment is displaced backwards with the risk of damage to the brachial artery. Common injury in children.

Example of treatment –

reduction of the displaced fracture under anaesthesia. Limb immobilised in plaster of Paris with elbow flexed.

Condyles

Cause –

relatively uncommon and occurs mainly in children.

Example of treatment –

plaster of Paris.

Radius (Figs 4.5 and 4.6)

Type

Long bone.

image

Fig. 4.5 Right radius (anterior aspect).

A–Head of radius

B–Neck of radius

C–Radial tuberosity

D–Oblique line

E–Lateral border

F–Interosseous border

G–Lower end of radius

H–Radial styloid process.

Right ulna (anterior aspect).

I–Ulnar styloid process

J–Medial border

K–Interosseous border

L–Ulnar tuberosity

M–Coronoid process

N–Trochlear notch

O–Olecranon process

P–Radial notch.

image

Fig. 4.6 Right radius (posterior aspect).

1 – Head of radius

2 – Neck of radius

3 – Radial tuberosity

4 – Lateral border

5 – Interosseous border

6 – Radial styloid process

7 – Ulnar notch.

Right ulna (posterior aspect).

8 – Ulnar styloid process

9 – Head of ulna

10 – Interosseous border

11 – Medial border

12 – Olecranon process.

Position

Lateral bone of the forearm.

Articulations

Head of radius with the radial notch of the ulna to form the superior radio-ulnar joint and with the capitulum of the humerus to form part of the elbow joint.

Lower end of the radius with the head of ulna to form the inferior radio-ulnar joint and with the scaphoid and lunate to form part of the wrist joint.

Main parts

Features of the upper end of the radius

Head –

rounded, with a concave superior surface and an articular circumference.

Neck –

narrow portion, inferior to the head.

Radial tuberosity –

medial aspect, below the neck, provides attachment for the biceps brachii muscle.

Features of the shaft of the radius

Anterior border

Posterior border

Interosseous border –

attached to the lateral aspect of the ulna by an interosseous membrane to form the middle radio-ulnar joint.

Anterior surface –

the location of the nutrient foramen.

Posterior surface

Lateral surface

Features of the lower end of radius

Ulnar notch –

located on the medial aspect; articulates with head of ulna to form part of the inferior radio-ulnar joint.

Radial styloid process –

prominent process on the lateral aspect which can be palpated.

Distal surface –

for articulation with the carpal bones.

Ossification

Primary centre

Shaft –

8th week of intrauterine life.

Secondary centres

2 centres:

lower end of radius appears age 1;

head of radius appears age 4–5.

Head of radius unites with the shaft age 14–17.

Lower end of the radius unites with the shaft age 17–19.

Ulna (Figs 4.5 and 4.6)

Type

Long bone.

Position

Medial bone of the forearm.

Articulations

Radial notch of the ulna with the head of the radius to form the superior radio-ulnar joint.

Head of ulna with the ulnar notch of the radius to form part of the inferior radio-ulnar joint.

Trochlear notch of the ulna with the trochlea of the humerus to form part of the elbow joint.

(The head of the ulna is covered with an articular disc and therefore does not directly take part in the formation of the wrist joint.)

Main parts

Features of the upper end of the ulna

Olecranon process –

postero-superior projection. It can be palpated on the posterior aspect of the elbow joint; it gives attachment to the triceps tendon.

Coronoid process –

anterior projection.

Ulnar tuberosity –

situated on the anterior surface of the coronoid process; provides attachment to the brachialis muscle.

Trochlear notch –

between the coronoid and olecranon processes; articulates with the trochlea of the humerus.

Radial notch –

depression on the lateral aspect of the coronoid process; articulates with the head of radius.

Features of the shaft of the ulna

Anterior border

Posterior border

Interosseous border –

attached to the medial aspect of the radius by an interosseous membrane.

Anterior surface –

the location of the nutrient foramen.

Medial surface

Posterior surface

Features of the lower end of the ulna

Head –

small and rounded.

Ulnar styloid process –

prominent process which can be palpated on the medial aspect of the wrist joint.

Ossification

Primary centre

Shaft –

8th week of intrauterine life.

Secondary centres

2 centres:

lower end of ulna appears age 5–6;

olecranon appears age 9–11.

Olecranon unites with the shaft age 14–16.

Lower end unites with the shaft age 17–18.

Radiographic appearances of the radius and ulna (Figs 4.7 and 4.8)

image

Fig. 4.7 Left forearm: anteroposterior projection.

A–Olecranon

B–Trochlea

C–Coronoid process

D–Ulnar tuberosity

E–Shaft of ulna

F–Head of ulna

G–Ulnar styloid process

H–Triquetral

I–Scaphoid

J–Radial styloid process

K–Lunate

L –Inferior radio-ulnar joint

M–Shaft of radius

N–Radial tuberosity

O–Neck of radius

P–Head of radius

Q–Capitulum

R–Humerus.

(From Bryan 1996.)

image

Fig. 4.8 Left forearm: lateral projection.

1 – Epicondyles of humerus

2 – Trochlea and capitulum

3 – Head of radius

4 – Neck of radius

5 – Radial tuberosity

6 – Shaft of radius

7 – Lunate

8 – Scaphoid

9 – Lower end of radius

10 – Head of ulna

11 – Shaft of ulna

12 – Coronoid process

13 – Trochlear notch

14 – Olecranon

15 – Shaft of humerus.

(From Bryan 1996.)

Insight

Due to the arrangement of the radius and ulna a fracture of the shaft of one of the bones is usually associated with a dislocation or fracture-dislocation of the other bone.

Fractures

Olecranon process

Usually occurs in adults.

Cause –

fall on the olecranon process.

Crack without displacement

Example of treatment –

plaster of Paris, elbow flexed to 90°.

Transverse with separation

Example of treatment –

open reduction and screw fixation, plaster of Paris.

Comminuted

Example of treatment –

excision of bone fragments and reattachment of the triceps tendon, plaster of Paris.

Head of radius

Usually occurs in adults.

Cause –

fall on the outstretched hand pushes the radial head against the capitulum.

Crack fracture –

most common.

Example of treatment –

collar and cuff sling.

Comminuted fracture

Example of treatment –

excision of radial head.

Mid-shaft radius and ulna

Cause –

indirect force, e.g. fall on the hand.

Example of treatment –

plaster of Paris, elbow to wrist.

Greenstick fracture

Occurs in children.

Cause –

direct force, e.g. blow on the forearm.

Example of treatment –

plaster of Paris, elbow to wrist.

Monteggia’s fracture-dislocation (Fig. 4.9)

Fracture of the upper third of the ulna with dislocation of the radial head.

image

Fig. 4.9 Monteggia’s fracture-dislocation.

Cause –

fall on the hand with forced pronation of the forearm.

Example of treatment –

plaster of Paris, axilla to head of metacarpals, elbow flexed 90° and forearm supinated; or internal fixation of ulnar fracture by plate and screws or intramedullary nail; plaster of Paris.

Galeazzi’s fracture-dislocation (Fig. 4.10)

Fracture of the lower third of the radius with dislocation of the head of the ulna.

image

Fig. 4.10 Galeazzi’s fracture-dislocation.

(From Sutton 1987.)

Cause –

fall on the hand with a rotational force.

Examples of treatment –

plaster of Paris, above elbow to head of metacarpals; or internal fixation of radius by plate and screws.

For fractures of the lower end of the radius and ulna, see wrist joint.

Hand (Fig. 4.11)

Carpal bones

Type

Short bones.

image

Fig. 4.11 Right hand (palmar aspect).

A–Shaft of proximal phalanx of middle finger

B–Shaft of middle phalanx of ring finger

C–Shaft of distal phalanx of little finger

D–Head of 5th metacarpal

E–Shaft of 5th metacarpal

F–Base of 5th metacarpal

G–Hamate

H–Pisiform

I–Triquetral

J–Lunate

K–Capitate

L–Scaphoid

M–Trapezoid

N–Trapezium

O–Shaft of 1st metacarpal

P–Base of proximal phalanx of thumb

Q–Base of distal phalanx of thumb

R–Shaft of 4th metacarpal

S–Shaft of 3rd metacarpal

T–Shaft of 2nd metacarpal

U–Base of proximal phalanx of index finger

V–Shaft of proximal phalanx of index finger

W–Head of proximal phalanx of index finger

1–Distal interphalangeal joint of index finger (synovial hinge joint)

2–Proximal interphalangeal joint of index finger (synovial hinge joint)

3–2nd metacarpophalangeal joint (synovial ellipsoid joint)

4–1st carpometacarpal joint (synovial saddle joint)

5–5th carpometacarpal joint (synovial plane joint).

Position

2 rows situated between the radius proximally and the bases of the metacarpals distally.

Insight

To remember the position of the scaphoid bones:

Left wrist palmar aspect

image

Articulations

Scaphoid with the radius, lunate, trapezoid, trapezium.

Lunate with the radius, scaphoid, capitate, triquetral.

Triquetral with the hamate, pisiform, lunate.

Pisiform with the triquetral.

Hamate with the 4th and 5th metacarpals, capitate, triquetral.

Capitate with the 2nd, 3rd and 4th metacarpals, hamate, lunate, scaphoid, trapezoid.

Trapezoid with the 2nd metacarpal, trapezium, scaphoid, capitate.

Trapezium with the 1st and 2nd metacarpals, trapezoid, scaphoid.

Ossification

Primary centres

Appear at the following times of life:

Capitate – 2nd month Scaphoid – 4th–5th year
Hamate – 3rd month Trapezium – 4th–5th year
Triquetral – 3rd year Trapezoid – 4th–5th year
Lunate – 4th year Pisiform – 9th–12th year.

N.B. The dates at which the carpal bones ossify are subject to considerable variation.

Metacarpal bones (Fig. 4.11)

Type

Miniature long bones.

Position

Distal to the carpal bones.

Articulations

1st metacarpal with the proximal phalanx of the thumb, and the trapezium.

2nd metacarpal with the proximal phalanx of the index finger, the trapezium, trapezoid and capitate.

3rd metacarpal with the proximal phalanx of the middle finger and the capitate.

4th metacarpal with the proximal phalanx of the ring finger, the capitate and the hamate.

5th metacarpal with the proximal phalanx of the little finger and the hamate.

Main parts

Head –

rounded; articulates with the corresponding proximal phalanx.

Shaft –

anterior border is concave longitudinally.

Base –

expanded; articulates with the appropriate carpal bones. The bases of the 2nd–5th metacarpals articulate with each other.

Ossification

Primary centre

Shaft –

9th week of intrauterine life.

Secondary centre

1 centre:

Base of 1st metacarpal appears age 2–3.

Head of 2nd–5th metacarpals appear age 2.

Secondary centre unites with the shaft age 15–19.

Phalanges (Fig. 4.11)

Type

Miniature long bones.

Position

Distal to the metacarpals, forming the fingers.

Articulations

5 proximal phalanges with the corresponding metacarpals and the 1st with the distal phalanx of the thumb, the 2nd–5th with the corresponding middle phalanges.

4 middle phalanges with the corresponding proximal and distal phalanges.

5 distal phalanges with the corresponding middle phalanges and the proximal phalanx of the thumb.

Main parts

Head –

expanded; in the distal phalanges supports the tissue of the finger tips.

Shaft –

anterior border is concave.

Base –

expanded; articulates with either the phalanx or the metacarpal proximal to it.

Ossification

Primary centre

Shaft –

8th–12th week of intrauterine life.

Secondary centre

1 centre:

Base of phalanges appears age 2–3.

Base unites with the shaft age 15–18.

Radiographic appearances of the hand (Figs 4.12, 4.13 and 4.14)

image

Fig. 4.12 Left hand: dorsipalmar projection.

A–5th metacarpal

B–Capitate

C–Hamate

D–Triquetrum

E–Pisiform

F–Ulnar styloid process

G–Lunate

H–Scaphoid

I–Trapezium

J–Trapezoid

K–Sesamoid bones

L–Metacarpopha- langeal joint

M–Proximal phalanx

N–Middle phalanx

O–Distal phalanx.

(From Bryan 1996.)

image

Fig. 4.13 Left hand: dorsipalmar oblique projection.

1 – Phalanges

2 – 5th to 2nd metacarpals

3 – Radius

4 – Scaphoid

5 – 1st metacarpal

6 – Phalanges.

(From Bryan 1996.)

image

Fig. 4.14 Rheumatoid arthritis: skeletal scintigraphy. Note increased uptake in several proximal and distal interphalangeal joints and the carpi.

Fractures

Metacarpals

Base, shaft or neck.

Cause –

due to a direct blow.

Example of treatment –

crepe bandage, if no displacement. Plaster of Paris, dorsal slab forearm to fingers if bones displaced.

Phalanges

Cause –

due to a direct blow.

Example of treatment –

splint for not more than 3 weeks or rehabilitation difficult.

Elbow joint (Figs 4.15, 4.16 and 4.17)

Type

Synovial hinge joint, continuous with the superior radio-ulnar joint.

image

Fig. 4.15 Left elbow joint (lateral aspect).

1 – Interosseous membrane

2 – Radius

3 – Annular ligament

4 – Radial collateral ligament

5 – Humerus

6 – Fibrous capsule

7 – Ulna.

image

Fig. 4.16 Left elbow joint (coronal section).

A–Humerus

B–Trochlea

C–Articular hyaline cartilage

D–Synovial fluid

E–Synovial membrane

F–Ulna

G–Radius

H–Superior radio- ulnar joint

I–Head of radius

J–Annular ligament

K–Fibrous capsule

L–Capitulum.

image

Fig. 4.17 Left elbow joint (sagittal section).

A–Humerus

B–Pad of fat

C–Synovial membrane

D–Articular hyaline cartilage

E–Olecranon process of ulna

F–Radius

G–Annular ligament

H–Synovial fluid

I–Pad of fat

J–Fibrous capsule.

Bony articular surfaces

Trochlea of the humerus articulates with the trochlear notch of the ulna. Capitulum of the humerus articulates with the head of the radius. The articular surfaces are covered with articular hyaline cartilage.

Fibrous capsule

Attached to the humerus at the level of the epicondyles; extending above the radial and coronoid fossae; incorporating the coronoid and olecranon processes of the ulna and the neck of the radius; blending with the annular ligament of the superior radio-ulnar joint.

Synovial membrane

Lines the fibrous capsule and the coronoid, radial and olecranon fossae and is continuous with superior radio-ulnar joint. There are pads of fat situated between the synovial membrane and the fibrous capsule above the radial, coronoid and olecranon fossae. The synovial membrane secretes synovial fluid, which lubricates the joint.

Supporting ligaments

Ulnar collateral ligament –

on the medial aspect of the joint, attached to the medial epicondyle of the humerus and the coronoid and olecranon processes of the ulna.

Radial collateral ligament –

on the lateral aspect of the joint, attached to the lateral epicondyle of the humerus and the annular ligament.

Annular ligament –

surrounds the head of the radius and is attached to the radial notch of the ulna.

Movements

Flexion by the biceps, brachialis and brachioradialis muscles.

Extension by the triceps muscle.

Blood supply

Brachial, ulnar and radial arteries forming an anastomosis.

Nerve supply

Musculo-cutaneous, radial and median nerves.

Insight

The carrying angle is larger in women than men because women have a wider pelvis than men, the angle gets its name from the fact that it allows people to carry items with their arms straight without the forearm catching on the hips.

Carrying angle

Medial angle between the long axes of the humerus and ulna – greater in women than men, the average angle being 163°.

Radiographic appearances of the elbow joint (Figs 4.18 to 4.22)

image

Fig. 4.18 Left elbow joint: anteroposterior projection.

A–Olecranon and coronoid fossae

B–Olecranon

C–Medial epicondyle

D–Trochlea

E–Coronoid process

F–Ulnar tuberosity

G–Ulna

H–Shaft of radius

I–Radial tuberosity

J–Neck of radius

K–Head of radius

L–Capitulum

M–Lateral epicondyle

N–Radial fossa

O–Shaft of humerus.

(From Bryan 1996.)

image

Fig. 4.22 Elbow: CT scan. Note the loose body anterior to the distal humerus (long arrow) and overgrowth of cartilage on the posterior aspect of the radial head (short arrow).

(From Resnick Kransdorf, 2005.)

image

Fig.4.19 Left elbow joint: lateral projection.

1 – Head of radius

2 – Tuberosity of radius

3 – Shaft of radius

4 – Shaft of ulna

5 – Tuberosity of ulna

6 – Coronoid process

7 – Trochlear notch

8 – Olecranon

9 – Trochlea and capitulum

10 – Epicondyles

11 – Supracondylar ridge

12 – Shaft of humerus.

(From Bryan 1996.)

image

Fig. 4.20 Left elbow joint: oblique projection.

A–Olecranon

B–Trochlear notch

C–Radial notch

D–Head of radius

E–Trochlea

F–Capitulum.

(From Bryan 1996.)

image

Fig. 4.21 Elbow: CT scan, coronal section.

1 – Coronoid process

2 – Ulna

3 – Shaft of radius

4 – Head of radius

5 – Humerus

6 – Tip of olecranon process.

(From Bryan 1996.)

Trauma

Supracondylar fracture

(In children this may be confused with the epiphyses, therefore it is usual to radiograph both elbows for comparison.)

Cause –

fall on the hand with the elbow flexed. Distal bone fragment is displaced backwards with the risk of damage to the brachial artery.

Example of treatment –

reduction of the displaced fracture under anaesthesia; plaster of Paris with the elbow flexed.

Elbow dislocation

Cause –

heavy fall on the outstretched hand. Radius and ulna displaced posteriorly or posteriorly and laterally. Damage to the brachial artery or one of the nerves may occur.

Example of treatment –

reduction under anaesthesia. Collar and cuff with the elbow flexed at 90°.

Wrist joint (Figs 4.23 and 4.24)

Type

Synovial ellipsoid joint.

image

Fig. 4.23 Left wrist joint (coronal section).

A–Fibrous capsule

B–Synovial membrane

C–Articular hyaline cartilage

D–Lower end of radius

E–Inferior radio-ulnar joint

F–Head of ulna

G–Articular disc

H–Synovial fluid

I–Triquetral

J–Lunate

K–Scaphoid.

image

Fig. 4.24 Left wrist joint (palmar aspect).

1 – Base of 1st metacarpal

2 – Trapezium

3 – Radial collateral ligament

4 – Palmar radiocarpal ligament

5 – Lower end of radius

6 – Head of ulna

7 – Palmar ulnocarpal ligament

8 – Ulnar collateral ligament

9 – Pisiform

10 – Hamate

11 – Capitate

12 – Trapezoid.

Bony articular surfaces

Distal end of the radius with the scaphoid and lunate. Articular disc of the inferior radio-ulnar joint with the lunate and triquetral. The carpal bones are united by interosseous ligaments. The articular surfaces are covered with articular hyaline cartilage.

Fibrous capsule

Attached to the distal end of the radius and ulna, the margins of the joint disc and the proximal aspects of the scaphoid, lunate and triquetral.

Synovial membrane

Lines the fibrous capsule and is separate from the membrane of the inferior radio-ulnar joint. It covers the parts of the bones not covered with articular hyaline cartilage and secretes synovial fluid, which lubricates the joint.

Supporting ligaments

Palmar radiocarpal ligament –

from the radius to the scaphoid, lunate and triquetral on the anterior aspect of the joint.

Palmar ulnocarpal ligament –

from the ulnar styloid process to the lunate and triquetral on the anterior aspect of the wrist.

Dorsal radiocarpal ligament –

from the radius to the scaphoid, lunate and triquetral on the posterior aspect of the wrist.

Ulnar collateral ligament –

on the medial aspect of the wrist, attached to the ulnar styloid process and the triquetral and pisiform.

Radial collateral ligament –

on the lateral aspect of the wrist, attached to the radial styloid process and the scaphoid.

Intracapsular structures

Articular disc –

situated at the distal end of the ulna.

Movements

Flexion by the flexor carpi radialis and flexor carpi ulnaris muscles.

Extension by the extensor carpi radialis and the extensor carpi ulnaris muscles.

Abduction by the flexor and extensor carpi radialis muscles.

Adduction by the flexor and extensor carpi ulnaris.

Blood supply

Radial and ulnar arteries.

Nerve supply

Ulnar, median and radial nerves.

Radiographic appearances of the wrist joint (Figs 4.25 to 4.30)

image

Fig. 4.25 Left wrist joint: posteroanterior projection.

A–5th metacarpal

B–Hook of hamate

C–Triquetral

D–Pisiform

E–Lunate

F–Ulnar styloid process

G–Shaft of ulna

H–Inferior radio-ulnar joint

I–Shaft of radius

J–Radial styloid process

K–Tubercle of scaphoid

L–Trapezium

M–Trapezoid

N–1st metacarpal

O–Base of 2nd metacarpal

P–Styloid process of 3rd metacarpal

Q–Capitate.

(From Bryan 1996.)

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Fig. 4.30 Wrist: MR scan. Erosion of the radial head (curved arrow) synovitis midcarpal and radiocarpal joints.

(From Resnick Kransdorf, 2005.)

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Fig. 4.26 Left wrist joint: lateral projection.

1 – 2nd to 5th metacarpal bones

2 – Hamate

3 – Head of capitate

4 – Triquetral

5 – Lunate

6 – Styloid process of ulna

7 – Head of ulna

8 – Ulna

9 – Radius

10 – Styloid process of radius

11 – Scaphoid

12 – Pisiform

13 – Crest of trapezium

14 – Trapezoid

15 – 1st metacarpal

16 – Thenar eminence.

(From Bryan 1996.)

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Fig. 4.27 Left wrist joint: posteroanterior oblique projection.

A–Hamate

B–Pisiform

C–Capitate

D–Triquetral

E–Lunate

F–Ulna

G–Radius

H–Scaphoid

I–Trapezoid

J–Trapezium

K–1st metacarpal.

(From Bryan 1996.)

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Fig. 4.28 Left wrist joint: anteroposterior oblique projection.

1 – 1st metacarpal

2 – Trapezoid

3 – Trapezium

4 – Scaphoid

5 – Radius

6 – Ulna

7 – Lunate

8 – Pisiform

9 – Triquetral

10 – Capitate

11 – Hook of hamate.

(From Bryan 1996.)

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Fig. 4.29 Wrist: MR scan.

A–Triquetral

B–Pisiform

C–Flexor tendons

D–Scaphoid

E–Lunate.

(From Bryan 1996.)

Trauma

Colles’ fracture (Fig. 4.31)

Transverse fracture of the radius with posterior and lateral displacement of the distal fragment. Ulnar styloid process often fractured.

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Fig. 4.31 Colles’ fracture.

Cause –

fall on a dorsi-flexed hand. (Common in elderly women who may have osteoporotic bones.)

Example of treatment –

plaster of Paris, below the elbow to the metacarpal necks. Wrist slightly palmar-flexed.

Smith’s fracture (Fig. 4.32)

Transverse fracture of the radius with anterior displacement of the distal fragment.

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Fig. 4.32 Smith’s fracture.

(From Sutton 1987.)

Cause –

flexion injury of the wrist joint (uncommon).

Example of treatment –

plaster of Paris, below the elbow to the metacarpal necks. Wrist held in dorsi-flexion.

Scaphoid fracture (Figs 4.33 and 4.34)

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Fig. 4.33 Scaphoid fractures.

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Fig. 4.34 Wrist, scaphoid fracture: radionuclide imaging. Note increased activity in the area of the scaphoid (arrowed).

(From Resnick Kransdorf, 2005.)

Most common carpal bone to fracture. Often not demonstrated radiographically until 10–14 days following injury. Transverse fracture, middle (waist).

Cause –

fall on the dorsi-flexed hand.

Example of treatment –

plaster of Paris, upper forearm to head of metacarpals and the proximal phalanx of the thumb.

Dislocations

Metacarpophalangeal and interphalangeal joints.

Cause –

forced hyperextension of the joint.

Example of treatment –

joints strapped in flexion for approximately 1 week.

INSIGHT

If a radiograph of the scaphoid is taken and a fracture is not demonstrated but the pain persists alternative imaging techniques may be required to demonstrate the fracture.

First carpometacarpal joint

Type

Synovial saddle joint.

Bony articular surfaces

The concave base of the first metacarpal with the convex, superior surface of the trapezium. The articular surfaces are covered with articular hyaline cartilage.

Fibrous capsule

Attached to the perimeter of the base of the first metacarpal and the rough edge round the articular surface of the trapezium. The capsule is thickened dorsally and laterally.

Synovial membrane

Lines the fibrous capsule and is separated from the other carpometacarpal joints. It covers the parts of the bone not covered with articular hyaline cartilage and secretes synovial fluid, which lubricates the joint.

Supporting ligaments

Lateral ligament –

from the lateral surface of the trapezium to the radial side of the base of the first metacarpal.

Palmar ligament –

an oblique band from the palmar surface of the trapezium to the ulnar aspect of the base of the first metacarpal.

Dorsal ligament –

an oblique band from the dorsal surface of the trapezium to the ulnar aspect of the base of the first metacarpal.

Movements

Flexion by the flexor pollicis, opponens pollicis and flexor pollicis longus.

Extension by the abductor pollicis longus, extensor pollicis brevis and extensor pollicis longus.

Abduction by the abductor pollicis brevis and the abductor pollicis longus.

Adduction by the adductor pollicis.

Axial rotation, a combination of the above movements.

N.B. Flexion is associated with medial rotation and in full extension the joint is slightly adducted.

Blood supply

Radial arteries.

Nerve supply

Median and radial nerves.

Fractures

Base of first metacarpal

Cause –

usually due to a force directed along the long axis of the bone, e.g. a metacarpal blow as in punching.

Transverse fracture

Example of treatment –

firm crepe bandage or plaster of Paris, forearm to proximal aspect of the first interphalangeal joint.

Bennett’s fracture-dislocation (Fig. 4.35)

Oblique fracture extending to the 1st carpometacarpal joint with dislocation of the thumb.

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Fig. 4.35 Bennett’s fracture-dislocation.

(From Sutton 1987.)

Example of treatment –

plaster of Paris or internal fixation by Kirschner wires.

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