Anorexic Analysis
Chapter 3 Muscles and Actions
Sternocleidomastoid (side of the neck)
Both sides working together produce flexion at the neck (cervical flexion). The right sternocleidomastoidproduces rotation to the left and lateral flexion to the right. The left sternocleidomastoid produces rotation to the right and lateral flexion to the left.
Deltoid (anterior, medial (or lateral), and posterior heads) (shoulder)
Abduction of the arm (all sections). The anterior fibres flex and horizontally adduct arm and the posteriorfibres extend and horizontally abduct the arm. This muscle should not be treated as a single muscle due to the opposite action of the anterior and posterior fibres.
Latissimus dorsi (wings of the back)
Extension and adduction at the shoulder joint.
Pectoralis major (clavicular head and sternal head) (chest)
Flexion, horizontal adduction and adduction at the shoulder joint. When the shoulder is flexed the pectoralis major will also act as an extensor. Note: When designing basic resistance training programs, there is no need to distinguish between the clavicular and sternal heads of this muscle.
Biceps brachii (biceps)
Flexion at the elbow joint; also a weak flexor of the shoulder. Many students think the biceps is the primary and strongest elbow flexor. In fact, the biceps is the strongest elbow flexor when the forearm is supinated (palm toward the body). However, if the forearm is pronated (palm away from the body), the brachioradialisis the strongest forearm flexor.
Brachialis (the little part of biceps under the main bicep, towards the inside of the arm)
Flexion of the elbow.
Brachioradialis (upper part of forearm towards the inside)
Flexion of the elbow.
Triceps (horse shoe on the back of the arm)
Extension at the elbow joint.
Trapezius (lower, middle, and upper fibres) (trapezoids)
The trapezius is very important for many shoulder girdle movements but its action on the scapula is quite complex and not emphasized in this text. Some of
Sternocleidomastoid (side of the neck)
Both sides working together produce flexion at the neck (cervical flexion). The right sternocleidomastoidproduces rotation to the left and lateral flexion to the right. The left sternocleidomastoid produces rotation to the right and lateral flexion to the left.
Deltoid (anterior, medial (or lateral), and posterior heads) (shoulder)
Abduction of the arm (all sections). The anterior fibres flex and horizontally adduct arm and the posteriorfibres extend and horizontally abduct the arm. This muscle should not be treated as a single muscle due to the opposite action of the anterior and posterior fibres.
Latissimus dorsi (wings of the back)
Extension and adduction at the shoulder joint.
Pectoralis major (clavicular head and sternal head) (chest)
Flexion, horizontal adduction and adduction at the shoulder joint. When the shoulder is flexed the pectoralis major will also act as an extensor. Note: When designing basic resistance training programs, there is no need to distinguish between the clavicular and sternal heads of this muscle.
Biceps brachii (biceps)
Flexion at the elbow joint; also a weak flexor of the shoulder. Many students think the biceps is the primary and strongest elbow flexor. In fact, the biceps is the strongest elbow flexor when the forearm is supinated (palm toward the body). However, if the forearm is pronated (palm away from the body), the brachioradialisis the strongest forearm flexor.
Brachialis (the little part of biceps under the main bicep, towards the inside of the arm)
Flexion of the elbow.
Brachioradialis (upper part of forearm towards the inside)
Flexion of the elbow.
Triceps (horse shoe on the back of the arm)
Extension at the elbow joint.
Trapezius (lower, middle, and upper fibres) (trapezoids)
The trapezius is very important for many shoulder girdle movements but its action on the scapula is quite complex and not emphasized in this text. Some of