Dance Anatomy & Kinesiology

418 Dance Anatomy and Kinesiology

Brachioradialis

As its name implies, the brachioradialis (brachium, arm +

radi, radius) runs between the upper arm and the radius.

This muscle arises above the lateral epicondyle of the

humerus and runs down to attach distally to the lower

radius just above the styloid process (figures 7.43 and

7.47, p. 425). It is the muscle that gives the rounded

contour to the lateral forearm. When this muscle con-

tracts it flexes the elbow. Due to its location, this muscle

has been theorized to bring the forearm to a midposition

(neutral position) from a position of either pronation or

supination.

Palpation: Sit with the fingers of the left hand on the

anterolateral aspect of the right forearm just distal to the

crease of the elbow, with the right elbow bent and the right

hand in a fist; have the thumb side of the fist under the

top of a desk (forearm in a midposition between pronation

and supination). You can see and feel the brachioradialis

contracting when you press your right fist up against the

desk. Move your fingers distally on the brachioradialis to

the distal radius to follow its course.

Posterior Elbow Muscles

The posterior elbow muscles include the triceps brachii

and the anconeus. Because these muscles attach distally

to the ulna rather than the radius, their contribution is not

influenced by the position of the forearm. Other extensors

of the wrist and fingers that cross the elbow joint posteri-

orly can also contribute to elbow extension but have been

omitted for purposes of simplicity.

Attachments and Primary Actions of Brachioradialis

Muscle Proximal attachment(s) Distal attachment(s) Primary action(s)

Brachioradialis

(bra-kee-o-ra-dee-A-lis)

Above lateral epicondyle of

humerus

Lateral aspect of styloid

process of radius

Elbow flexion

Radioulnar supination from

pronation or vice versa to

achieve midposition

FIGURE 7.43 Brachioradialis, pronator teres, and pro-

nator quadratus (right arm, anterior view).

Attachments and Primary Actions of Triceps Brachii

Muscle Proximal attachment(s) Distal attachment(s) Primary action(s)

Triceps brachii

(TRY-seps BRA-kee-eye)

Long head: just below

glenoid cavity of scapula

Lateral head: upper half of

posterolateral humerus

Medial head: lower two-

thirds of posterior humerus

Olecranon process of

ulna via a common

tendon

Elbow extension

(Shoulder extension—long head)

(Shoulder adduction—long head)