The document provides a detailed overview of the anatomy of the radius and ulna bones in the forearm, including their structure, muscle attachments, and ossification processes. It also discusses clinical conditions such as fractures (Colles's and Smith's fractures), congenital anomalies, and articulation with other bones. Key features of both bones are outlined, highlighting their functions and anatomical relationships.

1. Radius & Ulna Anatomy
Part-3
By Purvi Shah
BPT

2. Radius

3. Radius
The radius is the lateral bone of the forearm.
It is homologous with the tibia of the lower limb.
It has an upper end, a lower end and a shaft.

4. The Upper End
The Head is disc shaped & is covered with hyaline cartilage
Head of radius fits into a socket formed by radial notch of ulna
and annular ligament, thus forming superior radioulnar joint.
The Neck is enclosed by narrow lower margin of annular
ligament.
The Tuberosity lies just below the medial part of the neck.
It has a rough posterior part and a smooth anterior part.

5. The Upper End

6. The Shaft
It has three borders and three surfaces.
Borders
The Anterior Border
The Posterior Border(mirror image of the anterior border)
The Medial or Interosseous Border(sharpest border)

7. The Shaft
Surfaces
The anterior surface lies between anterior and interosseous
borders.
The posterior surface lies between the posterior and interosseous
borders.
The lateral surface lies between the anterior posterior borders.

8. The Lower End
It is widest part of the bone;it has a five surfaces.
The anterior surface (The radial artery palpated against this
surface)
The posterior surface(Presents 4 grooves for extensors tendons)
The medial surface(occupied by the ulnar notch for the head of
ulna)
The lateral surface (prolonged downwards to from styloid process)
The inferior surface(bears a triangular area for the scaphoid bone;

9. Muscle Attachments
 Biceps attaches to the radial tuberosity.
 Supinator,flexor pollicis longus and the flexor digitorum
superficialis attach to the upper third part of the shaft of the
radius.
EPB,abductor pollicis longus and pronator teres all attach to the
mid shaft of the radius.
Pronator quadratus muscle attach to the distal quarter of the
radial shaft.

10. Muscle Attachments

11. Articulation
Elbow Joint
Wrist Joint

12. Ossification
The shaft ossifies from a primary centre.
The lower end ossifies from a secondary centre.
The Upper end ossifies from a secondary centre.

13. Clinical Anatomy
 The Radius commonly gets fractured about 2 cm above its lower end
Colles’s fracture.
Mechanism of injury: Fall on outstretched hand(FOOSH)
Distal fragments is displaced upwards and backwards.
Reverse of the colles’s fracture: Smith fracture
Distal fragments being palmar flexed rather than dorsiflexion.

14. Distal End Of Radius Fracture

16. Clinical Anatomy
Congenital absence of the radius is rare anomaly.
Resulting gross radial deviation of the hand and the thumb is often
absent.
Radioulnar synostosis is also rare condition in which radius and
ulna are fused together.

17. Ulna

18. Ulna
The ulna is the medial bone of forearm.
It is homologous with fibula of lower limb.
It has a upper end, shaft, lower end.
The ulna is a long bone larger proximally than distally.

19. Upper End
Olecranon process projects upwards from the shaft.
It has superior, anterior, posterior, medial, lateral surfaces.
Coronoid process projects forwards from the shaft just below the
olecranon process.
It has four surfaces; superior, anterior, posterior, medial, lateral
surfaces.
The trochlear notch forms an articular surface.
The radial notch articulate with the head of radius.

20. The Shaft
It has a 3 Borders and 3 surfaces.
Borders
Interosseous border/Lateral border(sharpest)
Anterior border(thick and rounded)
Posterior border(subcutaneous)

21. The Shaft
Surfaces
Anterior surface
Medial surface
Posterior surface

22. Lower End
Head of the ulna
The lateral, distal end of the ulna is the head of the ulna.
 It articulates with the ulnar notch on the radius and with the
triangular articular disc in the Wrist Joint.
Styloid process
It projects downwards from the posteromedial side of lower end of
the ulna.

23. Muscle Attachments
Triceps inserts into the posterior of the olecranon process.
Brachialis inserts to anterior, inferior coronoid process.
Supinator arises from the supinator crest
FDS arises from a tubercle at the upper end of coronoid process.
Pronator teres arises medial margin of the coronoid process.

24. Muscle Attachments
FDP arises from the shaft of ulna.
Pronator quadratus origin from oblique ridge on lower part
anterior surface.
FCU arise from medial side of olecranon process.
ECU arises from posterior border
Anconeus is inserted lateral aspect of olecranon process.

26. Ligament Attachments
Capsular ligament
Annular ligament
Ulna collateral ligament

27. Articulation
Elbow joint
Radio-ulna joint

28. Ossification
The shaft and the most of the upper end ossify from a primary
centre.
The superior part of olecranon ossifies from a secondary centre.
The lower end ossifies from a secondary centre.

29. Clinical Anatomy
Shaft of ulna may fracture either alone or along with that of the
radius.
Fracture of olecranon is common caused by FOOSH
Dislocation of elbow is produced by FOOSH
Madelung’s deformity is dorsal subluxation of lower end of ulna.

30. Clinical Anatomy

31. Thank You