Elbow and Forearm Anatomy

 

 

• Bones

• Ligaments

• Musculature and Tendons

• Nerves

• Bursae

 

 

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Bones

The elbow and forearm consist of three main bones: the humerus, radius and ulna. The joint is comprised of articulations between the trochlea of the humerus with the ulna and the capitulum of the humerus with the head of the radius. This joint is an example of a hinge joint.

 

                                                Anterior View                                                                                            Posterior View

 

                                                                           

Bone Info:

http://physicaltherapy.about.com/od/humananatomy/p/elbowjoint.htm

 

 

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Ligaments

The elbow joint consists of three main ligaments: the ulnar collateral, radial collateral and annular.

 

Ulnar/Medial Collateral

Ligament is located on the medial side of the joint attaching to the medial epicondyle of the humerus and extending to the proximal portion of the ulna. This is a strong fan shaped condensation of the fibrous joint capsule. This ligament prevents excessive abduction of the elbow joint.

 

 

 http://www.eorthopod.com/images/ContentImages/elbow/elbow_anatomy/elbow_anatomy04b.jpg

 

 Radial/Lateral Collateral

Ligament is located on the lateral side of the joint attaching the lateral epicondyle and extending to the head of the radius. This is also a strong fan shaped condensation of the fibrous joint capsule. This ligament prevents excessive adduction of the elbow joint.

 

 

 

Annular

Ligament which encircles the head of the radius and is connected to the radial notch of the ulna. This is a strong ligament which stabilizes the radio-ulnar joint by holding the head of the radius in contact with the radial notch of the ulna.

 

 

Ligament Info:

http://physicaltherapy.about.com/od/humananatomy/p/elbowjoint.htm

 

 

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Musculature

 

Muscle	Action	Origin	Insertion	Innervation
Anconeus	Elbow extension  Stabilizes ulna during Supination and Pronation	Posterior Surface of lateral epicondyle	Lateral border of olecranon process	Radial
Biceps Brachii	Elbow flexion  Forearm supination Should flexion	Long head:Supraglenoid tuberosity Short head:coracoid process of scapula	Radial tuberosity	Musculocutaneous
Brachialis	Elbow flexion	Distal one-half of anterior humerus	Coronoid process of ulna Ulnar tuberosity	Musculocutaneous
Brachioradialis	Elbow flexion Forearm protonation Some forearm supination	Lateral supracondylar ridge of humerus	Styloid process of radius	Radial
Extensor Carpi Radialis Brevis	Wrist extension Radial deviation	Lateral epicondyle via  common extensor tendon Radial Collateral Ligament	Base of 3rd metacarpal	Radial
Extensor Carpi Radialis Longus	Wrist extension Radial deviation Elbow flexion	Supracondylar ridge of humerus	Radial side of 2nd metacarpal	Radial
Extensor Carpi Ulnaris	Wrist extension Ulnar deviation	Lateral epicondyle via common extensor tendon	Ulnar side of base of 5th metacarpal	Deep Radial
Extensor Digitorum Communis	Wrist extension Meta-carpel-phalangeal (MCP) extension Proximal-interphalangeal (PIP) extension	Lateral epicondyle via common extensor tendon	Into dorsal surface of base of middle and distal phalanges of each of the four fingers	Deep Radial
Flexor Carpi Radialis	Forearm protonation Wrist flexion Radial deviation Elbow flexion	Medial epicondyle via common extensor tendon	Palmar aspect of the bases of 2nd and 3rd metacarpal bones	Median
Flexor Carpi Ulnaris	Wrist flexion Ulnar deviation Elbow flexion	Humeral head: Medial epicondyle via common extensor tendon Ulnar head: Medial border of olecranon; proximal 2/3 of posterior ulna	Pisiform Hamate Palmar aspect of the base of the 5th metacarpal	Ulnar
Flexor Digitorum Profundus	Distal-interphalangeal (DIP) flexion PIP flexion Wrsit flexion	Anteromedial proximal 3/4 of ulna and associated interosseous membrane	Bases of the distal phalanges of the 2nd-5th digits	Lateral: Median Medial: Ulnar
Flexor Digitorum Superficialis	PIP flexion MCP flexion Wrist flexion	Humeral head: Medial epicondyle via common extensor tendon; ulnar collateral ligament Ulnar head: Coronoid process Radial Head: Oblique line of radius	Middle phalanges of the 2nd-5th digits	Median
Palmaris Longus	Wrist flexion	Medial epicondyle via common extensor tendon	Flexor retinaculum Palmar aponeurosis	Median
Pronator Quadratus	Forearm protonation	Anterior surface of distal 1/4 of ulna	Lateral portion of distal 1/4 of radius	Anterior interosseous
Pronator Teres	Forearm protonation Elbow flexion	Humeral head: Proximal to the medial epicondyle of humerus Ulnar head: coronoid process	Middle 1/3 of lateral radius	Median
Supinator	Forearm supination	Lateral epicondyle Radial collateral ligament Annular ligament Supinator crest of ulna	Proximal 1/3 of radius	Deep Radial
Triceps Brachii	Elbow extension Shoulder extension	Long head: Infraglenoid tubercle Lateral head: Posterolateral surface of the proximal 1/2 of humeral shaft Medial head: Posteromedial surface of humerus	Olecranon process of ulna	Radial

Muscle Info: 

Copyright: Starkey, Chad and Ryan, Jeffery, Evaluation of Orthopedic and Athletic Injuries, 2002, p. 494-495.

http://www.rad.washington.edu/staticpix/atlas/

 

 

 

 

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Nerves

 The elbow contains 3 nerves which pass through the joint. The nerves of the joint are: ulnar, radial, and median.

                                                                                                                                      

Ulnar Nerve

The ulnar nerve originates from the medial cord of the brachial plexus and travels down the humerus on the medial/posterior aspect going behind the medial epicondyle at the elbow. This nerve is sometimes referred to as the "funny bone" due to inadvertent impacts of the nerve at this point and the accompanying tingling sensation.

 

Radial Nerve

 The radial nerve originates from the posterior cord of the brachial plexus. It then travels posteriorly down the humerus on the medial side, enters a groove and then continues laterally down the humerus. At this point it enters the anterior aspect of the arm and passes in front of the lateral epicondyle when it reaches the distal portion of the humerus.

 

Median Nerve

 

 Nerve Info:

http://en.wikipedia.org/

 

 

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Bursae

There are only two bursae in the elbow region with clinical significance.  They are the subcutaneous olecranon bursa and the subtendinous olecranon bursa. 

 

Subcutaneous Olecranon Bursa

This bursa is located between the olecranon process and the skin, which makes it susceptible to trauma, such as a direct blow to the olecranon process.

 

 

 

 

Subtendinous Olecranon Bursa

This bursa is located between the tendon of the triceps brachii and the olecranon process.  Repetative stresses applied to the joint may cause this bursa to become inflammed. 

 

Click here to see an inflammed bursa illustration.

 

 *Starkey, Chad and Ryan, Jeffery, Evaluation of Orthopedic and Athletic Injuries, 2002, p. 494-495.

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