J Korean Acad Rehabil Med.  2004 Dec;28(6):592-595.

Anatomical Locations of the Motor Points of the Biceps Brachii and Brachialis Muscles

• Kim JS
• Kwon JY
• Kang SY
• Park JW

Abstract

OBJECTIVE
To identify the range of the precise locations of the motor points of biceps brachii and brachialis muscles in relation to bony landmarks. METHOD: Nine upper limbs of five male cadavers were dissected. The number and location of the motor points from the musculocutaneous nerve to biceps brachii and brachialis muscles were identified in relation to the bony landmarks. Bony landmarks were coracoid process and lateral epicondyle of the humerus. The length of the arm was defined as the distance from the apex of the coracoid process to the lateral epicondyle of humerus. The locations of the motor points were expressed as the percentage ratio of the length from the coracoid process to the motor points in relation to the length of the arm. RESULTS: First proximal motor points of the long head, short head of biceps brachii, and brachialis were located in 47.5 5.6%, 53.0 4.6%, 64.3 3.4% and second proximal points of them were 51.8 2.9%, 57.7 3.5%, 68.5 4.4% respectively. CONCLUSION: The identification of the locations of motor points related to the bony landmarks would increase the accuracy and ease of the motor point blocks to elbow flexors such as biceps brachii and brachialis muscles.

Keyword

Biceps brachii muscle; Brachialis muscle; Motor point; Bony landmark

MeSH Terms

Arm
Cadaver
Elbow
Head
Humans
Humerus
Male
Muscles*
Musculocutaneous Nerve
Upper Extremity