The functional anatomy of the elbow joint complex

is unique in orientation and configuration.

Three bones,
• the ulna,
• Radius, and
• Humerus,

They articulate to form four articulations:

• HUMEROULNAR,
• HUMERORADIAL,
• SUPERIOR RADIOULNAR, AND
• INFERIOR RADIOULNAR JOINTS.
§ The elbow joint, although non-weight bearing, may be the most complex
joint in the human body.
§ The elbow is a synovial hinge joint made up of articulations of mainly
the distal humerus and the proximal ulna.
§ However, articulations exist between the proximal radius and the
humerus as well as the proximal radius and ulna.
§ The three articulations are referred to as the ulnohumeral,
radiohumeral, and proximal or superior radioulnar joints respectively.
§ Many of the muscles of both the upper and lower arm either cross or
attach to at least one component of the elbow joint making it no surprise
that after the shoulder, the elbow joint is the second most commonly
injured joint in sports-related injuries
§ The elbow is a complex synovial joint which allows
for significant motion and function primarily in the form
of extension and flexion, however, the elbow joint also
facilitates motion in the hand in the form of supination and
pronation of the forearm.

§ This unique osseous structure provides the elbow excellent

static stabilization, which is enhanced by the ulnar collateral
ligament, the lateral collateral ligament, and the elbow joint
capsule.

§ The main stability of the elbow joint results from the osseous
articulations of the trochlea of the humerus and the ulnar
olecranon. The olecranon resembles a scoop or a wrench in
which a landmark referred to as the trochlear notch, fits around
the trochlea of the humerus and serves as the primary pivot
point during flexion and extension of the elbow joint.
§ The trochlear notch wraps around the humerus almost 180
degrees, while the trochlea of the humerus is wide with a central
groove, this allows for a tight conforming of the two structures,
adding to the stability.

§ After the osseous articulations of the humerus and ulna

(ulnohumeral articulation), the rest of the major stability
components of the elbow joint comes from two strong ligaments
in the form of the medial collateral ligament (MCL) and the
lateral collateral ligament (LCL). Both the LCL and the MCL
form into the joint capsule to provide further stability
• The elbow is a hinged joint which connects the upper arm to
the forearm and is made up of the humerus, ulna and
radius.

• The joint capsule surround the joint is further strengthened

by ligaments reinforcing stability.

• The muscles around the elbow produce the movements of

extension and flexion.

Ø A fibrous capsule encloses the joint, internally lined by

synovial membrane.
§ It consists of two separate articulations:

§ TROCHLEAR NOTCH OF
THE ULNA AND

§ THE TROCHLEA OF THE HUMERUS

§ ARTICULATION:

§ HEAD OF THE RADIUS AND THE

§ CAPITULUM OF THE HUMERUS

§ SUPERIOR RADIOULNAR JOINT

§ INFERIOR RADIOULNAR JOINT

Proximal radioulnar joint .
•It is articulation between the head of the radius and the radial
notch of the ulna (CONNECTED BY ANNULAR LIGAMENT)

• The radial head is held in place by the annular radial

ligament, which forms a ‘collar’ around the joint. The
annular radial ligament is lined with a synovial membrane,
reducing friction during movement.

•The annular ligament stabilizes the proximal radioulnar joint

Distal radioulnar joint
§ located near the wrist

§ It is an articulation between the ulnar notch of

the radius and the ulnar head. (CONNECTED BY
ARTICULAR DISC )

§ Movement is produced by the head of the radius

rotating within the annular ligament.
 § Radial collateral ligament

§ Ulnar collateral ligament

§ The Medial collateral ligament is a

triangular-shaped ligament made up of
three smaller ligaments named the anterior
oblique ligament, posterior oblique
ligament, and the transverse ligament, also
sometimes called Cooper's ligament
§ The anterior oblique ligament is the
strongest and most important medial
stabilizer of the elbow joint and protects
against excessive valgus forces.
• The joint of the elbow is strengthened by ligaments medially and
laterally.

• The radial collateral ligament is found on the lateral side of the

joint, extending from the lateral epicondyle, and blending
with the annular ligament of the radius (a ligament from the
proximal radioulnar joint).

• The ulnar collateral ligament originates from the medial

epicondyle, and attaches to the coronoid process and olecranon
of the ulna.
• Resist varus stress

• Radial collateral ligament

• The lateral collateral ligament is also

composed of three parts; the annular
ligament, the lateral radial collateral
ligament, and the lateral ulnar collateral
ligament.
• The three components of the LCL provide
stability during varus stresses applied on
the elbow and posterolateral rotational
stability.
• The ulnar collateral ligament complex of the elbow,
(medial side)which is comprised of the anterior bundle
[AB, more formally referred to as the medial ulnar
collateral ligament (MUCL)],

• posterior (PB), and

• transverse ligament, is commonly injured in overhead

throwing athletes.
• The AB or MUCL is the strongest component of the
ligamentous complex and the primary restraint to
valgus stress.

• MUCL is commonly required to restore elbow function

and stability
§ As a synovial joint, the elbow has a synovial membrane as
well as a joint capsule which are separated from each
other by fat pads.
§ These fat pads are located superficial to areas of
stress. These areas include the olecranon, coronoid and
radial fossa.
§ During flexion and extension, these fat pads are pulled
away by attachments to the brachialis and the triceps
brachii to allow space for bony processes.
§ A lubricating bursa, namely the olecranon bursa,
facilitates triceps action.
§ This bursa serves as a lubricating component between the
olecranon process of the ulna and the triceps tendon of
insertion
§ Twenty-three muscles are directly associated with the elbow
joint and can be classified into four main groups:

§ THE ELBOW FLEXORS,

§ EXTENSORS,
§ FLEXOR-PRONATOR AND,

§ EXTENSOR-SUPINATOR GROUPS.

§ These muscles provide dynamic stabilization to the elbow

and enable the hand to perform skilled, precise motions.
§ Many muscles cross over and attach around the elbow
joint.

§ These muscles are responsible for the secondary

stabilization of the joint.

§ The majority of the muscles originating from the elbow

joint provide very little motion at the elbow joint itself,
but rather act as flexors and extensors of the wrist,
hand, and digits.

§ Contribution to elbow stability comes in the form of

protection against varus and valgus forces.
§ Muscles which act primarily on the elbow joint include those
responsible for flexion, including
§ BICEPS BRACHII,
§ BRACHIORADIALIS, AND
§ BRACHIALIS.

§ The biceps brachii has a modest impact on elbow flexion and

acts as the primary muscle responsible for supination.

§ The biceps brachii is especially unique as it has two distal

attachments at the elbow joint, a more laterally oriented tendon
inserting on the proximal radius, and a medially oriented
aponeurosis which continues into the fascia of the proximal
forearm
§ Extension of the elbow joint
is accomplished almost entirely from
contraction of the TRICEPS BRACHII
with very modest action from the
anconeus muscle
• Muscles that protect against valgus forces include

• FLEXOR DIGITORUM SUPERFICIALIS,

• FLEXOR CARPI ULNARIS,

• FLEXOR CARPI RADIALIS, AND THE

• PRONATOR TERES.
Muscles that contribute to varus stability by initiating a valgus force include extensor digitorum communis, extensor carpi radialis
brevis and longus, anconeus, and extensor carpi ulnaris.
 ELBOW FLEXION

ELBOW EXTENSION
SUPINATION

PRONATION
§ Pronation

§ Supination.

§ These rotational movement occurs when

distal end of radius moves on distal end
of ulna by rotating the radius in the
pivot joint form.
§ SUPINATOR

§ BICEPS BRACHII

§ BRACHIORADIALIS
§ PRONATOR TERES

§ PRONATOR QUADRATUS
§ PALMAR

§ DORSAL

§ PROXIMAL

§ DISTAL
§ CARPAL BONES

§ She Looks Too Pretty Try To

Catch Her.
OSTEOLOGY OF WRIST

LOWER OR DISTAL END OF RADIUS

RADIOCARPAL JOINT
• The wrist joint (also known as the RADIOCARPAL
JOINT) is a synovial joint marking the area of
transition between the forearm and the hand.
§ Articulating Surfaces:

§ The wrist joint is formed by:

§ Distally – The proximal row of the carpal bones

(except the pisiform).

§ Proximally – The distal end of the radius, and the

articular disk
§ The carpus(carpal bones) controls length-tension
relationships in the multiarticular hand muscles
and to allow fine adjustment of grip
§ The joints formed between the carpal bones are
known as the intercarpal joints and most are of
the plane synovial type, as the bones interlock
with each other the rows are sometimes referred
to as two single synovial joints.
§ The arrangement of the bones and ligaments
allows very little movement between bones, but
they do slide contributing to the finer
movements of the wrist
§ The ligaments allow the bones to move in all
directions.
§ These ligaments meld together to form the joint
capsule of the wrist.
§ The joint capsule is a watertight sac of tissue that
surrounds the wrist bones.
§ Inside the wrist capsule are the joints themselves.
The joint capsule contains a small amount of
lubricant, called synovial fluid, that allows the
bones to move together easily.
§ Radial And Ulnar Collateral Ligaments – a pair of ligaments which
bind the bones of the wrist and provide stability
§ Volar Radiocarpal Ligaments – a complex web of ligaments that
support the palm side of the wrist
§ Dorsal Radiocarpal Ligaments – ligaments that support the back of
the wrist
§ Ulnocarpal And Radioulnar Ligaments – two sets of ligaments that
provide the main support for the wrist.
§ The stability of the wrist is provided by ligaments on the palmar
aspect is the flexor retinaculum which together with the carpal bones
forms a canal.
The wrist is an ellipsoidal (condyloid) type of synovial joint, allowing for flexion, extension,
ulnar and radial deviation
§ Muscles of the forearm that cross the
carpal joint will produce flexion or
extension at the wrist joint
§ Flexors – movements causing flexion
§ Produced mainly by the

§ Flexor Carpi Ulnaris,

§ Flexor Carpi Radialis, with assistance from the flexor

digitorum superficialis.
§ Extensors – muscle causing extension
§ Produced mainly by the

§ Extensor Carpi Radialis Longus And Brevis,

And

§ Extensor Carpi Ulnaris, With Assistance From

The

§ Extensor Digitorum.
§ ADDUCTORS/ULNAR DEVIATORS :
muscles causing ulnar deviation at wrist

§ Produced by the

§ Extensor Carpi Ulnaris And

§ Flexor Carpi Ulnaris

§ Abductors/ radial deviators – muscles causing
radial deviation

§ Extensor Carpi Radialis Longus & Brevis

§ Abductor Pollicis Longus