T h e E l b o w F l exo rs BY ANTHONY LETT
There are in fact several muscles that we refer to when we talk about flexing the elbow. The biceps, or “guns’ as they are referred to, are just one of a group. The biceps brachii, brachialis, brachioradialis, and pronator teres are primary elbow flexors. Each of these muscles produces a force that passes anterior to the medial-lateral axis of rotation at the elbow.
Anatomy The biceps brachii attaches proximally on the scapula and distally on the radial tuberosity on the radius (Image 1). Secondary distal attachments include the deep fascia of the forearm through an aponeurotic sheet known as the bicipital aponeurosis (fibrous lacertus, see Image 2). The biceps produce its maximal electromyographic (EMG) signal when performing both flexion and supination simultaneously, such as when bringing a spoon to the mouth. The biceps exhibit relatively low levels of EMG activity when flexion is performed with the forearm deliberately held in pronation. This lack of muscle activation can be verified by self-palpation. IMAGE 1
The Bi(two)ceps Brachii with the long head highlighted.
IMAGE 2
With the bicipital aponeurosis highlighted.