The document discusses the anatomy of the elbow joint and forearm muscles. It describes the elbow joint as the articulation between the humerus, ulna, and radius bones. It is made up of three joints: the humero-ulnar joint, humero-radial joint, and proximal radio-ulnar joint. The document outlines the bones, ligaments, and capsular structures that make up the elbow joint. It also describes the muscles that flex, extend, pronate, and supinate the forearm.

1. Musculoskeletal Anatomy
Dr. Mohammad Yabroudi, PT, MSc, PhD
Department of Rehabilitation Sciences
Jordan University of Science &
Technology
Lecture 4

2. 2
Elbow Joint
• Articulation of humerus with ulna and radius
• Ulna articulates with trochlea of humerus
• Radius articulates with capitulum of humerus
• Interosseous membrane between ulna & radius provides
site for muscle attachment

3. 3
Humerus --- Distal End
• Forms elbow joint with
ulna and radius
• Capitulum
– articulates with head of
radius
• Trochlea
– articulation with ulna
• Olecranon fossa
– posterior depression for
olecranon process of
ulna
• Medial & lateral
epicondyles
– attachment of forearm
muscles

4. Ulna & Radius
4

5. 5
Ulna & Radius --- Proximal End
• Ulna (on little finger side)
– trochlear notch articulates with
humerus & radial notch with radius
– olecranon process forms point of elbow
• Radius (on thumb side)
– head articulates with capitulum of
humerus & radial notch of ulna
– tuberosity for muscle attachment

6. 6
Ulna and Radius - Distal End
• Ulna --styloid process
– head separated from wrist joint by fibrocartilage disc
• Radius
– forms wrist joint with scaphoid, lunate & triquetrum
– forms distal radioulnar joint with head of ulna

7. Elbow joint
3 joints within single capsule:
• Humero-ulnar or Ulno-humeral
• Humero-radial or Radio-humeral
• Proximal radio-ulnar
7

8. The Ulno-humeral Joint
• It’s a uniaxial synovial hinge joint
• It has one degree of freedom
• It’s made of the trochlea of the Humerus
and the olecranon process of the Ulna

9. The Radio-humeral Joint
• It’s a uniaxial synovial joint
• It’s made of the capitulum of the Humerus
with the head of the Radius

10. The Proximal Radio-ulnar Joint
• It’s a uniaxial synovial pivot joint
• It’s made of the head of radius
which is held to the proximal ulna
• It allows pronation and supination
of the forearm
• The middle radioulnar articulation
is not a synovial joint but rather an
interosseous membrane between
the 2 bones

11. 11
Articular Capsule of the Elbow Joint
• Radial annular ligament hold head of radius in place
• Collateral ligaments maintain integrity of joint

12. Elbow joint
Attachments:
• Proximal to olecranon, coronoid
and radial fossas
• Medial and lateral margins of
trochlear notch
• Distal to annular ligament
• Distal & lateral to coronoid
process
Joint Capsule:
Anterior View
12

13. Elbow joint
Attachments:
• Proximal to olecranon coronoid
and radial fossas
• Medial and lateral margins of
trochlear notch
• Distal to annular ligament
• Distal & lateral to coronoid
process
Joint Capsule:
Posterior View
13

14. Elbow joint
• Posterior capsule
– Taut in flexion
– Lax in extension
• Anterior capsule:
– Taut in extension
– Lax in flexion
Joint Capsule:
14

15. Elbow joint
• 3 bundles:
– Anterior
– Intermediate
– Posterior
Medial Collateral Ligament (MCL):
15

16. 16

17. Elbow joint
• Radial collateral
ligament
• Ulnar collateral
ligament
• Acessory collateral
ligament
Lateral Collateral Ligament (LCL):
17

18. Elbow joint
• Anterior ligament
• Oblique ligament
18

19. Proximal Radioulnar Joint
• Annular ligament
• Quadrate ligament
19

20. ROM and Movements
• Flexion: 0 – 140/150
• Extension: 140 – 0
• Hyperextension (in some people): 0 – 10
• Pronation: 0 – 90
• Supination: 0 – 90

22. 22
Muscles that Move the forearm
Forearm flexors
 Biceps brachii:
- arises from tubercle above glenoid
cavity of scapula (long head), and
from coracoid process of scapula
(short head).
- inserts onto radial tuberosity and
bicipital aponeurosis.
- innervated by musculocutaneous
nerve.
- flexes forearm at elbow joint,
supinates forearm at radioulnar
joint, and flexes arm at shoulder
joint.

23. 23
Muscles that Move the forearm
Forearm flexors
 Brachialis:
- arises from distal, anterior surface
of humerus.
- inserts onto ulnar tuberosity and
coronoid process of ulna.
- innervated by musculocutaneous
nerve.
- flexes forearm at elbow joint.

24. 24
Muscles that Move the forearm
Forearm flexors
 Brachioradialis:
- arises from lateral border of distal
end of humerus.
- inserts superior to styloid process
of radius.
- innervated by radial nerve.
- flexes forearm at elbow joint and
supinate and pronate forearm at
radioulnar joint to neutral
position.

25. 25
Muscles that Move the forearm
Forearm extensors
 Triceps brachii:
- arises from infra glenoid tubercle
of scapula (long head), lateral and
posterior surface of humerus
superior to radial groove (lateral
head), medial head originated
from entire posterior surface of
humerus to a groove for the radial
nerve.
- inserts onto olecranon of ulna.
- innervated by radial nerve.
- extends forearm at elbow joint and
extends arm at shoulder J.

26. 26
Muscles that Move the forearm
Forearm extensors
 Anconeus:
- arises from lateral epicondyle of
humerus.
- inserts onto olecranon and
superior portion of shaft of
ulna.
- innervated by radial nerve.
- extends forearm at elbow joint.

27. 27
Muscles that Move the forearm
Forearm pronators
 Pronator teres:
- arises from medial epicondyle of
humerus and coronoid process
of ulna.
- inserts onto midlateral surface of
radius.
- innervated by median nerve.
- pronates forearm at radioulnar
joint.

28. 28
Muscles that Move the forearm
Forearm pronators
 Pronator quadratus:
- arises from distal portion of shaft
of ulna.
- inserts onto distal portion of
shaft of radius.
- innervated by median nerve.
- pronates forearm at radioulnar
joint.

29. 29
Muscles that Move the forearm
Forearm supinator
 Supinator:
- arises from lateral epicondyle of
humerus and ridge near radial
notch of ulna (supinator crest).
- inserts onto lateral surface of
proximal one third of radius.
- innervated by deep radial nerve.
- supinates forearm at radioulnar
joint.

30. Good Luck