The document discusses the anatomy and biomechanics of the elbow complex. It describes the bones, joints, ligaments, and muscles that make up the elbow. The elbow complex includes the humeroulnar joint, humeroradial joint, and proximal and distal radioulnar joints. It allows flexion/extension of the forearm and pronation/supination from the rotation of the radius. Key muscles like the biceps, brachialis, and triceps act across these joints to enable movement. Common injuries like tennis elbow and supracondylar fractures are also mentioned.

1. The elbow complex
By : Vinay Verma
MPO 1st year

2. Contents
 Introduction
 Anatomy of the elbow complex
 Applied anatomy

3. Introduction
 The joints and muscles of the elbow complex are designed to serve the
hand.
 They provide mobility for the hand in space by shortening and lengthening
the upper extremity.
 Rotation : provides additional mobility for the hand.
 The elbow complex structures also provide stability for skilled or forceful
movements of the hand when performing activities with tools .
 Around 16 muscles that cross the elbow complex also act at either the
wrist or shoulder and therefore the wrist and shoulder are linked with the
elbow in enhancing the functions of hand.

4. Anatomy of the elbow joint
 Structure : Humero-Ulnar and Humero-Radial Articulations
 Function : Humero-Ulnar and Humero-Radial Articulations
 Structure : Proximal and Distal Radio-Ulnar Articulations
 Function : Radio-Ulnar Joints

5. Structure : Humero-Ulnar and Humero-
Radial Articulations
Articulating surface on the humerus
 Distal part of humerus takes part.
 Anterior aspect:
 Trochlea
 Capitulum
 These structures articulates between the
medial and lateral epicondyle of humerus.

6. Structure : Humero-Ulnar and Humero-
Radial Articulations
Trochlea
 For the part of Humero-Ulnar articulations
 Hourglass shaped
 Has a groove called Trochlear Grove
Carrying angle : The medial portion of trochlea
projects distally more than the lateral portion resulting in
VALGUS ANGLULATION of the forearm .
 Normal :
 In males – 13 degree ;
 In females – 15 degree

7. Structure : Humero-Ulnar and Humero-
Radial Articulations
Capitulum:
 Forms the part of Humero-Radial Articulations
 Spherical shaped
 The indentation located on the humerus just above the
capitulum is called the Radial Fossa.
 It is designed to receive the head of radius in elbow
flexion

8. Structure : Humero-Ulnar and Humero-
Radial Articulations
Posterior view : Olecranon fossa
 Posteriorly, the distal humerus is indented by a deep
fossa called the olecranon fossa
 It is designed to receive the olecranon process of
the ulna at the end of the elbow extension ROM

9. Structure : Humero-Ulnar and Humero-
Radial Articulations
Articulating surface on the Radius and Ulna
Radius
 Bones taking part- Proximal end of the radius, known as the Head of
the Radius
 The radial head has a slightly cup-shaped concave surface called the
Fovea that is surrounded by a rim.
 The radial head’s convex rim fits into the Capitula trochlear groove.

10. Structure : Humero-Ulnar and Humero-
Radial Articulations
Ulna :Bones taking part- proximal end of ulna, known
as Trochlea.
 Deep, semicircular, concave surface called the Trochlear
notch.
 The proximal portion of the is divided into two unequal
parts by the Trochlear ridge, which corresponds to the
trochlear groove on the humerus

11. Articulations : Humero Radial joint
 Articulating surface- radial head and the capitulum of
humerus.
 Sliding of the shallow concave radial head over the
convex surface of the capitulum occurs.
 Joint surfaces INCONGRUENT- (because of the humeral
capitulum slightly smaller than the corresponding radial
fovea).
 In full extension, no contact occurs between the
articulating surfaces. In flexion, the rim of the radial
head slides in the capitula-trochlear groove.
 And enters the radial fossa as the end of the Flexion
range is reached.

12. Articulations : Humero Ulnar Joint
 Articulating surfaces- Humeral trochlear on the ulnar trochlear notch

14. Joint capsule Attachments
Anteriorly
 Proximal humeral attachment, just above the Coronoid and
radial fossae.
 Distally, the capsule attaches into the ulna along the margin of
the coronoid process and blends with the proximal border of
the Annular ligament.
Posteriorly
 Attached to the humerus along the upper edge of the
olecranon process and back of the medial epicondyle.
 The capsule passes just below the Annular ligament to attach
to the posterior and inferior margins of the neck of Radius

15. Ligaments
 Most of hinge joint in the body have collateral ligaments,
Including elbow.
 Collateral ligaments are located on the medial and lateral side
of the joint Known as Medial(ulnar) and Lateral(radial)
collateral ligament.
 FUNCTION:- it provide medial and lateral stability and to keep
joint surfaces in apposition

16. Medial collateral ligament

17. 1. Anterior medial collateral Ligament

18. 2. Posterior collateral ligament

19. 3. Transverse collateral ligament

20. Lateral collateral ligament

21. Lateral (radial) collateral ligament

22. Lateral ulnar collateral ligament

23. Functions of ligaments
 Stabilizes elbow against Varus stress.
 Stabilizes against combined Varus and supination torque (Minor 2 degree
laxity).
 Reinforces humero-radial joint and helps provide some resistance to longitudinal
distraction of the articulating surfaces
 Stabilizes the Radial head, thus providing a stable base of rotation
 Maintains posterolateral rotatory stability.

24. Muscles

25. Muscles crossing the elbow joint

27. Flexors of the elbow

28. Major flexors of the
elbow

29. Major flexors of the elbow

30. Extensors of Elbow
Triceps :
3 heads : Long head, Medial head and
Lateral head
Insertion : Into the posterior part of
superior surface of olecranon process of
ulna.
Nerve supply : Radial nerve
Action : extension of elbow, long head
extension and adduction.

31. Extensors of Elbow

32. FUNCTIONAL BIOMECHANICS: ELBOW JOINT
(HUMEROULNAR AND HUMERORADIAL ARTICULATIONS
 Axis of motion
The axis of motion is centered in the middle of the trochlea on a
line that intersects the longitudinal (anatomic) axis of the humerus.
An exact axis of motion is important because of the need to position
elbow prosthesis so as to correctly mimic elbow joint motion.

33.  Long axis of humerus and forearm
When the upper extremity is in the anatomical position, the long
axis of the humerus and the forearm form an acute angle
medially when they meet at the elbow.
This normal valgus angulation is called the carrying angle or
cubitus valgus
Functional use of the carrying angle results from a combination
of shoulder lateral rotation, elbow extension, and forearm
supination,
which enables a person to carry a bucket in one hand in such a
manner as to avoid contact between the carried load and lower
limb on the same side.

34.  Mobility and stability
A number of factors determine the amount of motion that is available at the elbow joint.
These factors are :
A. Active range of motion (flexion) : 135°-145°
B. Passive range of motion (flexion) : 150°-160°
C. Position of forearm : Supination >> ROM >> Pronation/neutral
D. Body mass index (BMI) : High BMI – Less ROM
E. The position of the shoulder may affect the range of motion available to the elbow because
of the two joint muscles that cross both the shoulder and elbow.
These muscles, the biceps brachii and the triceps brachii, may limit range of motion at the
elbow if a full range of motion is attempted at both joints simultaneously.

35.  Two-Joint Muscle Effects on Elbow Range of Motion
Two or multi-joint muscles do not have sufficient length to allow a simultaneous full range of
motion at all joints crossed. For example, in passive motion, passive tension in the triceps
brachii may limit full elbow flexion when the shoulder is simultaneously moved into full flexion
In active motion, torque produced by the long head of the biceps brachii may diminish as the
muscle is excessively shortened over both joints in full active shoulder and elbow flexion.

36.  Muscle action
1. Flexors
A. Brachialis
 Mobility muscle, large strength potential and large work capacity.
 Torque produced is greatest at more than 100° elbow flexion.
 Inserted on ulna so unaffected by rotation of radius.
 Being a one joint muscle, it is not affected by position of shoulder.
 Active in all types of contractions (isometric, concentric and
eccentric).
B. Biceps brachii
 Mobility muscle, largest volume of long head but less CSA.
 Torque produced is greatest between 80°- 100°.
 Affected by position of shoulder; both heads cross shoulder and
elbow.
 Active during unresisted elbow flexion with forearm supinated or
neutral in both concentric and eccentric contractions.

37. C. Brachioradialis
 The brachioradialis is inserted at a distance from the joint axis,
and therefore stable lever arm.
 Small cross-sectional area
 The peak moment arm between 100°-120° of elbow flexion.
 The brachioradialis does not cross the shoulder and therefore is
unaffected by the position of the shoulder.
 The position of the elbow joint affects brachioradialis only
during voluntary maximum eccentric contractions.
The pronator teres, as well as the palmaris longus,
flexor digitorum superficialis, flexor carpi radialis, and
flexor carpi ulnaris, is a weak elbow flexor with primary
actions at the radioulnar and wrist joints.

38. 2. Extensors
A. Triceps Brachii
 The long head’s ability to produce torque may diminish when full
elbow extension is attempted with the shoulder in hyperextension.
 In this instance, the muscle is shortened over both the elbow and
shoulder simultaneously.
 The medial and lateral heads of the triceps, being one-joint
muscles, are not affected by the position of the shoulder.
 The medial head is active in unresisted active elbow extension ,
but all three heads are active when heavy resistance is given to
extension.

39.  Maximum isometric torque is generated at a
position of 90° of elbow flexion. The triceps is
active eccentrically to control elbow flexion
as the body is lowered to the ground in a
push-up
 The triceps is active concentrically to extend
the elbow when the triceps acts in a closed
kinematic chain, such as in a push-up
 The triceps may be active during activities
requiring stabilization of the elbow.

41. Tennis elbow
• Also called lateral epicondylitis
Golfer’s elbow
• Also called medial epicondylitis
Student’s elbow
• Also called olecranon bursitis
Cubitus varus and valgus
Anconeus epitrochlearis

44. Cubitus valgus Cubitus varus
The application of a valgus stress
to the forearm produces
compression on the lateral aspect
of the elbow joint and tensile
stress on the medial joint aspect.
The application of a varus stress
to the forearm produces tensile
stress on the lateral aspect of the
elbow joint and compression on
the medial joint aspect.

45. Anconeus Epitrochlearis

46. Injuries at or around elbow

47. Patho-anatomy and
mechanism of injuries
 Supracondylar fracture of humerus
The fracture is caused by a fall on an
outstretched hand, forcing the elbow in
hyperextension resulting in fracture of humerus
above condyles.
Complications
Volkmann's Ischaemia contracture, myositis
ossificans, Gun Stock Deformity(varus
deformity) etc.

48.  Fracture of lateral epicondyle of humerus
A common fracture in children, it results from a varus injury to
the elbow
Complications
Non-Union, Cubitus Valgus deformity, Osteo Arthritis
Diminished growth at the lateral side of distal humerus epiphysis
results in a cubitus valgus deformity
 Intercondylar fracture of Humerus
Results from a fall on the point of elbow so that the olecranon is
driven into distal humerus, splitting the two humeral condyles
apart.
Complications
Stiffness of the elbow, malunion and osteoarthritis

49. Structure : Proximal and Distal Radio-Ulnar Articulations

50. Introduction
 Proximal and distal Radio-Ulnar joints are linked and
function as one joint.
 Type : Synovial Joint (diarthrodial)
 Variety : Pivot
 Uniaxial : The two joints acting together produce
supination and pronation of forearm and have 1° of
freedom of motion.
 6 ligaments and 4 muscles are associated with these
joints.

51. Proximal and Distal Radio-Ulnar Joint :
Articulations
Proximal Radio Ulnar Articulations Distal Radio Ulnar Articulations
Radial notch of ulna Ulnar notch of Radius
Annular Ligament Articular disc
Head of radius Head of ulna
Capitulum of humerus

52. Proximal and Distal Radio-Ulnar Joint :
Ligaments
Proximal Radio Ulnar Ligaments Distal Radio Ulnar Ligaments
Annular ligament Dorsal Radio ulnar ligament
Quadrate ligament Palmar radio ulnar ligament
Oblique cord Interosseous membrane

53. Proximal and Distal Radio-Ulnar Joint :
Muscles

54. Pronators of Radio-Ulnar Joints
Pronator teres Pronator Quadratus
Origin Medial epicondyle of humerus and
coronoid process of ulna
Distal quadrater of ulna and lower
part of ulna
Insertion Middle of lateral surface of radius
just below supinator muscle
Distal quadrator of radius and
lower border of anterior surfaces
Nerve supply Median nerve Median nerve
Action Pronation of forearm and weak
flexor of elbow
Pronation and distal radio ulnar
stabilization.

55. Supinator of Radio Ulnar joint
 Supinator muscle
Origin : Lateral epicondyle of humerus , supinator crest of ulna, radial
collateral ligament, annular ligament of radius
Insertion: Inserted into upper part of lateral surface of radius.
Nerve supply : Radial Nerve
Action : Supination

56. Functional Biomechanics : Proximal and
Distal Radio-Ulnar Joints
 Axis of Motion
The axis of motion for pronation and supination is a
longitudinal axis extending from the center of the radial
head to the center of the ulnar head.
In supination, the radius and ulna lie parallel to one
another, whereas in pronation, the radius crosses over
the ulna.

57.  Range of Motion
A total range of motion of 150° has been ascribed to the radioulnar joints.
 Muscle Action
Pronators - The pronators produce pronation by exerting a pull on the radius,
which causes its shaft and distal end to turn over the ulna.
The pronator teres has its major action at the radioulnar joints.
The pronator quadratus is active in unresisted and resisted pronation and in slow
and fast pronation.
The pronators are most efficient around the neutral position of the forearm when
the elbow was flexed to 90°.
The pronation torque generation was greatest with the forearm in supinated
positions.

58.  Muscle action
Supinator
The supinator, act by pulling the shaft and distal end of the
radius over the ulna.
The supinator muscle may act alone during unresisted slow
supination in all positions of the elbow or forearm.
However, activity of the biceps is always evident when
supination is performed against resistance and during fast
supination when the elbow is flexed to 90°.
Peak torque of moment arm shown at 40° to 50° of pronation.
The biceps brachii exert four times as much supination torque
with the forearm in the pronated position than with other
forearm positions.
The supinator are stronger than the pronators.

60. Dislocation at elbow joint
Pulled elbow (Nursemaid’s elbow)
Olecranon fracture
Radial head fracture
Colles fracture
Smith fracture
Barton fracture

61.  Dislocation at elbow joint
Posterior dislocation is the commonest type of elbow dislocation.
Other dislocations are posteromedial, postero-lateral, and
divergent.
It may be associated with fracture of the medial epicondyle,
fracture of the head of the radius, or fracture of the coronoid
process of the ulna.
 Pulled elbow (Nursemaid’s elbow)
This condition occurs in children between 2-5 years of age. The
head of the radius is pulled partly out of the annular ligament
when a child is lifted by the wrist.
The child starts crying and is unable to move the affected limb.
The forearm lies in an attitude of pronation

62.  Fracture of olecranon
This is usually seen in adults. It results from a direct
injury as in a fall onto the point of the elbow.
Complications
Non-union, elbow stiffness and osteoarthritis.
 Fracture of head of Radius
This is seen in adults, in contrast to fractures of the neck
of the radius which occurs in children. It is a valgus
injury.
Types of fracture head of radius. (a) Un-Displaced
(b) Fragment < 1/3 (c) Fragment >1/3 (d) Comminuted

63. Colle’s fracture (Dinner
fork deformity)
 The Colle’s fracture is most commonly
caused by a fall, landing on an
outstretched hand with the wrist in
dorsiflexion.
 Tension on the volar aspect of the wrist
causes bending and compressive forces. As
a result of these forces through the wrist,
dorsal displacement and comminution
occur.

64. Smith fracture (Goyrand Fracture)
 A Smith fracture is a fracture of the distal radius featuring volar displacement or angulation. It
typically results from a fall on the dorsum of the hand with a flexed wrist.
 Volar displacement of the distal radius can occur with a fall onto the palm of the hand.

65. Colle’s vs Smith Fracture

66. Barton’s Fracture
 Barton fracture is a compression injury with a marginal shearing fracture of the distal
radius.
 The most common cause of this injury is a fall on an outstretched, pronated wrist.
 The compressive force travels from the hand and wrist through the articular surface of the
radius, resulting in a triangular portion of the distal radius being displaced dorsally along
with the carpus.

67. Thank you