Elbow And Forarm Flashcards
Motions of the Elbow Complex
It consists of two interrelated joints, the humeroulnar joint and the humeroradial joint.
•Flexion and extension
Carrying angle of the elbow is described as the angle formed by the long axis of the humerus and forearm.
•It provides for improved functional range of motion (ROM) with elbow joint motion.
•Carrying angle in women is typically about 10 to 15 degrees while the carrying angle for men is about 5 degrees.
Strength Characteristics
of the Elbow Complex
The four elbow flexors are the biceps, brachialis, brachioradialis and, to a lesser degree, the pronator teres.
•Elbow flexor muscles are strongest at the mid-range of elbow flexion, or at about 90 degrees.
Biceps muscle is a stronger flexor muscle when combined with forearm supination.
•Brachialis muscle is a true elbow flexor having no effect on forearm rotation.
•The pronator teres contributes to elbow flexion only against resistance.
Four Problems
of the Elbow Complex
Ulnar Nerve Entrapment (cubital tunnel syndrome)
Distal Biceps Tendon Rupture
Lateral Epicondylitis (tennis elbow
Ulnar Collateral Ligament Reconstruction
Muscles of the elbow complex are divided by function into flexors, extensors, pronators, and supinators.
Flexors of the elbow complex are the biceps brachii, brachialis, and the brachioradialis muscles.
•The biceps muscle is a stronger elbow flexor with the radioulnar joint supinated.
•The brachialis muscle is the primary elbow flexor and is strong whether the forearm is in supination or pronation.
●“Workhorse” of elbow flexion
Brachioradialis muscle is
third elbow flexor.
•It is the strongest when flexing the elbow with the forearm in neutral
due to its more lateral and distal attachment at the styloid process of
the radius.
The extensor muscles of the elbow complex are the triceps brachii and the anconeus.
Triceps has no role in forearm rotation because it has no attachment to the rotating radius.
•The main role of the anconeus is to pull on the annular ligament when it contracts, which keeps the ligament from being pinched in the olecranon fossa with elbow extension
Muscle Actions of the
Elbow Complex
The muscles that cause pronation at the radioulnar joint (or the palm facing down) are the pronator teres and the pronator quadratus muscles.
•Supination (or the palm facing up) is accomplished by the biceps brachii and the supinator muscles.
•Biceps is the primary supinator of the radioulnar joint.
•Supinator muscle is a secondary forearm supinator.
Muscles, Nerves, and
Spinal Cord Levels
Biceps brachii Musculocutaneous C5, C6
•Brachialis Musculocutaneous C5, C6
•Brachioradialis Radial C5, C6
•Triceps Radial C6, C7, C8
•Anconeus Radial C6, C7, C8
•Pronator teres Median C7, C8
•Pronator quadratus Radial C7, C8, T1
•Supinator Radial C6
Lateral collateral
Maintains the ulnohumeral and radiohumeral joints when the elbow is loaded in supination
Annular
●Prevents subluxation of the radial head.
●Restrains the radial head and maintains the relationship with the ulna and humerus.
Medial collateral
Most important to provide stability against valgus stress, especially in the range of 20 to 130 degrees of extension and flexion.
Radioulnar Joint
Annular
●Prevents subluxation of the radial head
●Restrains the radial head and maintains the relationship with the ulna and humerus
•Interosseous membrane
●Supports radius and ulna, keeping them from separating.
ROM of the Elbow Complex
Elbow flexion 0 to 140 degrees
•Elbow extension 140 to 0 degrees
•Forearm supination 0 to 80 degrees
•Forearm pronation 0 to 80 degrees
