2. Introduction
• The elbow joint is a synovial joint ( HINGE TYPE) found
in the upper limb between the arm and the forearm.
• It is the point of articulation of three bones: the humerus of
the arm and the radius and the ulna of the forearm.
• Synovial joints, also called diarthroses, are free movable
joints. The articular surfaces of the bones at these joints are
separated from each other by a layer of hyaline cartilage.
• Smooth movement at these joints is provided by a highly
viscous synovial fluid, which acts as a lubricant
3. • Synovial joints can be further categorized based on function. The
elbow joint is functionally a hinge joint, allowing movement in only
one plane (uniaxial).
4. Osteology
There are three bones that comprise the elbow joint:
• the humerus
• the radius
• the ulna
These bones give rise to two joints:
• Humeroulnar joint
• Humeroradial joint
5. Joints
• Humeroulnar joint is the joint between the trochlea on the medial
aspect of the distal end of the humerus and the trochlear notch on the
proximal ulna.
• Humeroradial joint is the joint between the capitulum on the lateral
aspect of the distal end of the humerus with the head of the radius.
6. • The humeroulnar and the humeroradial joints are the joints that give
the elbow its characteristic hinge like properties.
• The rounded surfaces of the trochlea and capitulum of the humerus
rotate against the concave surfaces of the trochlear notch of the ulna
and head of the radius.
• At the elbow joint, the proximal ends of the radius and ulna articulate
with each other at the proximal radioulnar joint
7. • This joint, however, is considered to be a
separate articulation than those forming the
elbow joint itself.
• The proximal radioulnar joint is the
articulation between the circumferential head
of the radius and a fibro-osseous ring formed
by the radial groove of the ulna and the
annular ligament that hold the head of the
radius in this groove.
• The proximal radioulnar joint is functionally
a pivot joint, allowing a rotational movement
of the radius on the ulna.
8. Articulating Surfaces
The elbow joint consists of two separate articulations:
• Trochlear notch of the ulna and the trochlea of the humerus
• Head of the radius and the capitulum of the humerus
9. • Here are is a mnemonic that can help you
remember the articulations involved in the
elbow joint.
• CRAzy TULips
• Capitulum = RAdius (capitulum of the humerus
articulates with the head of radius)
• Trochlea = ULnar (the trochlea of the humerus
articulates with the trochlear notch of the ulna)
10. Joint Capsule and Bursae
• Like all synovial joints, the elbow joint has a
capsule enclosing the joint.
• This in itself is strong and fibrous,
strengthening the joint.
• The joint capsule is thickened medially and
laterally to form collateral ligaments, which
stabilise the flexing and extending motion of
the arm.
11. A bursa is a membranous sac filled with synovial fluid. It acts
as a cushion to reduce friction between the moving parts of a
joint, limiting degenerative damage. There are many bursae in
the elbow, but only a few have clinical importance:
• Intratendinous – located within the tendon of the triceps
brachii.
• Subtendinous – between the olecranon and the tendon of
the triceps brachii, reducing friction between the two
structures during extension and flexion of the arm.
• Subcutaneous (olecranon) bursa – between the olecranon
and the overlying connective tissue (implicated in
olecranon bursitis).
12. Ligaments of the elbow joint
• There are a collection of ligaments that connect the bones forming the
elbow joint to each other, contributing to the stability of the joint.
• The humeroulnar and the humeroradial joints each have a ligament
connecting the two bones involved at the articulation:
• the ulnar collateral ligaments
• the radial collateral ligaments
13. ulnar collateral ligament
• The ulnar collateral ligament extends from the medial epicondyle of
the humerus to the coronoid process of the ulna.
• It is triangular in shape, and is composed of three parts: an anterior, a
posterior and an inferior band.
14. The radial collateral ligament
• The radial collateral ligament has a low attachment to the lateral
epicondyle of the humerus.
• The distal fibers blend with the annular ligament that encloses the
head of the radius, as well as with the fibers of the supinator and the
extensor carpi radialis brevis muscles
15. • The annular ligament also reinforces the
joint by holding the radius and ulna together
at their proximal articulation.
• The quadrate ligament is also present at this
joint, and maintains constant tension during
pronation and supination movements of the
forearm.
18. Movements
• As the elbow joint is a hinge joint, movement is in
only one plane. The movements at the elbow joint
involve movement of the forearm at the elbow joint.
• Flexion of the forearm at the elbow joint involves
decreasing the angle between the forearm and the
arm at the elbow joint.
• Extension involves increasing the angle between the
arm and forearm. These movements are performed
by two groups of muscles in the arm: the anterior
compartment and the posterior compartment of the
arm.
19. Flexion
• Most of the muscles producing flexion are found in the anterior
compartment of the arm. There are two muscles in this compartment
that produce flexion at the elbow joint:
Biceps Brachii
Brachialis
20. Biceps Brachii originates as two heads.
• The tendon of the long head originates from the
supraglenoid tubercle of the scapula. It passes through the
joint capsule of the shoulder joint and through the bicipital
groove on the anterior surface of the humerus.
• The short head of the biceps brachii muscle originates
from the coracoid process of the scapula. These heads join
together to form the biceps brachii muscle belly.
• The muscle inserts via a single tendon onto the radial
tuberosity distal to the elbow joint. In the forearm, there is
a continuation of this tendon as a flattened connective
tissue sheath, the bicipital aponeurosis.
• This aponeurosis blends with the deep fascia in the anterior
forearm.
21.
22. • Brachialis originates from the distal half of the anterior surface of
the humerus, as well as from the intermuscular septa on either side of
the anterior compartment.
• It is located deep to the biceps brachii muscle. It forms a singular
tendon that inserts onto the tuberosity of the ulna.
23. • Both the biceps brachii and brachialis muscles are innervated by the
Musculocutaneous nerve.
• While the biceps brachii and the brachialis muscles are the main flexors of the
elbow joint, the brachioradialis muscle is also involved in the flexion of the forearm
at this joint.
• Brachioradialis originates from the lateral aspect of the distal humerus above the
lateral epicondyle.
• It inserts onto the lateral aspect of the distal radius. Although this muscle is
primarily in the forearm, it crosses the elbow joint so therefore it acts on the elbow
joint. It is innervated by the radial nerve.
24. • Mnemonic
• Learning the muscles that bend the elbow becomes child's play if you anchor them
to a mnemonic like the one below.
3 B's bend the elbow
Biceps
Brachialis
Brachioradialis
25. Extension
• Extension of the forearm at the elbow joint is the increase of the angle
at the elbow to bring the forearm back to the anatomical position from
a flexed position.
• There is one muscle involved in extension, the triceps brachii muscle.
It is the only muscle in the posterior compartment of the arm.
26. • Triceps Brachii originates as three heads.
• The long head originates from the infra glenoid tubercle of the scapula,
the lateral head originates from the lateral aspect of the humerus above
the radial groove, and the medial head originates from the medial
aspect of the humerus below the level of the radial groove.
• The three heads converge on a single tendon that inserts onto the
olecranon of the ulna. It is supplied by the radial nerve, which passes
down through the arm in the radial groove between the lateral and
medial heads of the muscle
27. • While flexion and extension are the only
movements that can occur at the elbow joint itself,
movement is also afforded at the proximal
radioulnar joint, which contributes to the elbow
joint.
• Movements at this joint are called pronation and
supination.
• These are rotational movements that occur when
the distal end of the radius moves over the distal
end of the ulna by rotating the radius in the pivot
joint formed by the circular head of the radius, the
radial groove of the ulna and the annular ligament.
28. • Pronation and supination are easily visualized when the elbow is flexed at 90°.
• Supination is where the palm of the hand is facing upwards; pronation is the
rotation of the forearm so that the palm is facing downwards.
• In the anatomical position, the forearm is in the supine position. Pronation in the
anatomical position is movement of the forearm so that the palm is facing
posteriorly.
29. Carrying angle
• Normal alignment of elbow is determined by measuring the normal carrying angle
Normal carrying angle 5-15degree
More in female than in males
