RADIUS BONE & BONES OF HAND
LEARNING OBJECTIVES
Students should able to
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Recognize the bones of forearm &hand
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Determine side of bones.
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Identify the features of bones.
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Identify the muscles attached to bones.
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Identify clinical significance of bones.
RADIUS BONE
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Lateral bone of forearm
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Three Parts
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Upper end

Head

Neck

Tuberosity
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Shaft
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Lower end
DETERMINATION OF SIDE
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Upper end rounded & bears the head.
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Lower end more wider than the upper end
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Lateral surface of shaft is convex & its anterior surface is concave in lower part
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Styloid process projects from lateral surface of the lower end
HEAD
Disc-shaped, overhangs the neck on all sides
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Medially it articulates with radial notch of ulna.
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Upper surface articulates with capitulum-- form elbow joint
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It is covered with hyaline cartilage.
•Medial
surface articulates with radial notch of ulna to form superior radio-ulnar joint
Attachment
 Annular ligament to the articular cicumference of head
NECK
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Constricted part below head
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Surrounded by lower part of annular ligament
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Attachments:
Supinator is inserted into the lateral
anterior &posterior aspects of neck
TUBEROSITY
Lies below the medial part of the neck.
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Attachments:
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Biceps brachii is inserted into rough posterior part.
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Smooth anterior part is related to bursa.
SHAFT
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Narrow above, broader below
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Three borders.
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Interosseous(medial)
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Anterior
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Posterior
Three surfaces
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Anterior
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Posterior
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Lateral
BORDERS
INTEROSSEOUS (MEDIAL) BORDER
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Sharp except at its upper part
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Begins from posterio-inferior part of radial tuberosity
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Lower end form posterior boundary of small triangular area above ulnar notch of radius
Attachment on interosseous border
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Pronator quadratus is inserted
Gives attachment to interosseous membrane in lower 3\4
ANTERIOR BORDER
Begins just below antero-lateral part of radial tuberosity
Upper & lower parts are sharp
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Attachments on anterior border
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Origin of Flexor digitorum superficialis from upper & lower parts
Extensor retinaculum is attached to lower edge
POSTERIOR BORDER
Begins from posterio-inferior part of tuberosity
End in dorsal tubercle at back of lower end
Prominent in middle part
•
•
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SURFACES
ANTERIOR SURFACE
Lies between anterior and interosseous border
Presents nutrient foramen directed up ward
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Attachments on anterior surface
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Origin to flexor pollicis longus from upper 2\3
Insertion to pronator quadratus in lower 1\4
POSTERIOR SURFACE
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•
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Lies between interosseous & posterior borders
Origin of Abductor pollicis longus from upper part
Origin of Extensor pollicis brevis from lower part
LATERAL SURFACE
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•
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Lies between anterior&posterior borders
Rough ridge in middle part gives insertion to pronator teres
Insertion to supinator into V Shape area at upper part
Brachioradialis is inserted just above styloid process
LOWER END
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Expanded &rectangular
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Has five surfaces
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Lateral surface
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Medial surface
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Anterior surface
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Posterior surface
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Inferior surfaces
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LATERAL SURFACE
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•
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Present styloid process
Radial collateral ligament of wrist joint is attached at tip of styloid process
Brachiodialis is inserted into lower part of lateral surface
Two grooves lateral to styloid process for tendons of Abductor pollicis longus
&Extensor pollicis brevis
MEDIAL SURFACE
Bears ulnar notch for articulation with head of ulna
Articular disc of inferiorradio-ulnar joint is attached to ridge at lower part.
ANTERIOR SURFACE
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In form of thick prominent ridge
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Radial artery is palpated as radial pulse
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Pronator quadratus is inserted into the lower part of anterior surface
POSTERIOR SURFACE
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Irregular
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Present dorsal tubercle(of lister)
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Four grooves for extensor tendons
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INFERIOR SURFACE
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•
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Bears triangular area for Scaphoid bone
Medially, quadrangular area for Lunate
Takes part in forming wrist joint
CLINICAL ANATOMY
Fractures of radius
Fracture of head
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Can occur from fall on outstretched hand
Fracture of neck of radius
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Occur in young children
FRACTURES OF SHAFT OF
RADIUS
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May or may not occur with ulna
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Displacement of fractured fragment depends on pull of
muscle
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Supinator and biceps supinate the proximal fragment
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Pronator quadratus pronates the distal fragment
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Brachioradialis and extensor carpi radialis and brevis shortens the fore arm
COMBINE FRACTURES OF RADIUS AND ULNA
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•
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Shaft of ulna fractured by a force from behind
Bowing forward of ulnar shaft with anterior dislocation of radial head
Rupture of annular ligament
COMBINE FRACTURES
OF RADIUS AND ULNA
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Proximal third of radius is fractured
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Distal end of ulna is dislocated at distal radio
ulnar joint
FRACTURES OF DISTAL END
Colles’ fracture
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Fall on outstretched hand
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Distal fragment is displaced posteriorly and superiorly
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The fore arm and wrist resembles the shape of dinner fork
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Dinnerfork deformity
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Reverse colles’s fracture
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Distal fragment displaced anteriorly
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Fall on back of hand
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BONES OF HAND
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Eight carpal bones
Five metacarpal bones
Fourteen phalanges
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Eight carpal bones
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Arranged in two rows
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CARPAL BONES
Proximal row
Medial to lateral
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Scaphoid
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Lunate
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Triquetral
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Pisiform
Distal row
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Trapezium
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Trapezoid
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Capitate
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Hamate
CHARACTERISTICS OF EACH BONE
Each bone has six surfaces.

Scaphoid is boat –shaped
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tubercle on its lateral side

Lunate is half moon shaped or crescentic

Triquetral is pyramidal shape
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has oval facet on distal part of palmar surface

Pisiform is pea shaped
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only one oval facet on proximal part of dorsal surface

Trapezium is quadrangular in shape
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crest & groove anteriorly

Trapezoid resemble shoe of baby

Capitate is largest with rounded head

Hamate is wedge –shaped with hook near base
ATTACHMENTS
Most important structure related with carpal bones --------- FLEXOR RETINACULUM
Attachment:
Lateral
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scaphoid
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anterior border of lower end
Medial
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Pisiform
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Hamitate
CLINICAL ANATOMY
Fracture of scaphoid
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Most common fractured bone among carpal bone
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Non union & avascularity common problem
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Tenderness & swelling in anatomical snuff box
Dislocation of lunate
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Most common dislocated bone of carpal bone
May compress median nerve in front of wrist
Carpal tunnel syndrome
CARPAL TUNNEL SYNDROME
Carpal tunnel:
• osseofibrous space formed by anterior concave surface of carpus and flexor retinaculum
• Passage of long flexor tendon and median nerve
CARPAL TUNNEL SYNDROME
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Syndrome is caused by compression of median nerve due to reduced size of canal
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Pain and paraesthesia of lateral one and half finger
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Weakness of thenar muscle
METACARPAL BONES
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Short long bones
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Numbered from lateral to medial side
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1st metacarpal Shorter & thicker articulates with trapezium.
Other metacarpal bones
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Expanded bases articulate with distal row of carpal bones & with each other
Middle metacarpal show styloid process
Heads has boldly rounded articular facets
Form concavity for palm
Heads form knuckles of fist
PHALANGES
14 in number
Parts

Base

Shaft

Head