Dance Anatomy & Kinesiology

420 Dance Anatomy and Kinesiology

Anconeus

The anconeus (ancon, elbow) is a small muscle located just distal to the triceps brachii (figure 7.44B).

It runs downward and medially from its proximal attachment on the lateral epicondyle of the humerus

to its distal attachment on the posterior upper ulna. Its actions are to stabilize the elbow (Basmajian

and DeLuca, 1985) and assist with elbow extension.

Palpation: Using the same movement as just described for palpation of the triceps brachii, you can

feel the anconeus contracting when placing the fingertips of your left hand just lateral to the olecranon

process of the ulna when the right hand presses down on the seat of the chair.

Summary of Elbow Muscle

Attachments, Actions, and Roles in Movement

The muscles that cross the elbow joint serve to stabilize the joint as well as produce flexion and exten-

sion. A summary of attachments and actions of key muscles of the elbow are included in table 7.6,

while the movements of the elbow and the muscles that can produce them are included in table 7.7.

These tables also include key muscles and movements of the radioulnar joints, which will shortly be

described in more detail in the text.

TABLE 7.6 Summary of Attachments and Primary Actions of the Muscles of the Elbow and Radioulnar Joints

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

Biceps brachii

(BY-seps BRA-kee-eye)

Long head: just above

glenoid cavity of scapula

Short head: coracoid process

of scapula

Tuberosity of radius

via a common tendon

Elbow flexion

Radioulnar supination

(Shoulder flexion—long head)

(Shoulder abduction when shoulder in

external rotation—long head)

(Shoulder adduction—long head)

Brachialis

(BRA-kee-al-is)

Anterior aspect of lower half

of humerus

Upper ulna Elbow flexion

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

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)

Anconeus

(an-KO-nee-us)

Posterior aspect of lateral

epicondyle of humerus

Lateral aspect

of olecranon process

of ulna

Upper posterior ulna

Assists with elbow extension

Pronator teres

(PRO-na-tor TE-reez)

Medial epicondyle

of humerus

Coronoid process of ulna

Lateral aspect of

middle third of radius

Radioulnar pronation

(Assists with elbow flexion)

Pronator quadratus

(PRO-na-tor kwod-RA-tus)

Anterior aspect of lower

quarter of ulna

Anterior aspect

of lower quarter

of radius

Radioulnar pronation

Supinator

(soo-pi-NA-tor)

Lateral epicondyle

of humerus

Lateral aspect of upper ulna

Anterolateral aspect

of upper radius

Radioulnar supination