Elbow Flexion
is primarily
accomplished by a concentric contraction of the Biceps
Brachii, Brachialis, & Brachioradialis when the elbow is
flexed against gravity or resistance.
Biceps brachii
The biceps brachii has two heads which originate
as follows:
Long head: supraglenoid tubercle above the superior lip of the glenoid
fossa
Short head: coracoid process of the scapula and upper lip of the glenoid
fossa.
The biceps brachii inserts
on the tuberosity of the radius and bicipital aponeurosis. It is
easily palpated on
the anterior aspect of the humerus and elbow and is innervated
by the musculocutaneous nerve (C5,6).
Brachialis
The brachialis originates
on the distal half of the anterior portion of the humerus and inserts
on the coronoid process of the ulna. It may be palpated
on the lateral side of the upper arm under the biceps brachii muscle and
is innervated by
the musculocutaneous nerve and sometimes branches from radial and median
nerves (C5,6)
.Brachioradialis
The brachioradialis originates
on the distal two thirds of the lateral condyloid (supracondylar)
ridge of the humerus and inserts
on the lateral surface of the distal end of the radius at the styloid
process. It may palpated
on the lateral anterior side of the forearm and is innervated
by the radial nerve (C5,6).
|
Elbow Extension
is primarily
accomplished by a concentric contraction of the Triceps
Brachii when
the elbow is extended against gravity or resistance.
Triceps brachii
The triceps brachii has three heads which originate
as follows:
Long head: infraglenoid tubercle below inferior lip of glenoid fossa of
the scapula.
Lateral head: upper half of the posterior surface of the humerus.
Medial head: distal two thirds of the posterior surface of the humerus.
The triceps brachii inserts
on the olecranon process of the ulna.
It is palpated on
the posterior and lateral aspects of the humerus and is innervated
by the radial nerve (C7,8). |
