Which muscles are involved in shoulder flexion?
The muscles involved in the flexion movement include the anterior deltoid, pectoralis major and coracobrachialis. For a shoulder extension, your body uses the latissimus dorsi, teres major and minor and posterior deltoid muscles.
What 3 motions occur at the acromioclavicular joint?
At the AC joint, during full flexion and external rotation of the humerus, both upward rotation (approximately 30°) and external rotation (approximately 8°) were measured.
Which muscle is involved in shoulder movements?
The primary muscle group that supports the shoulder joint is the rotator cuff muscles. The four rotator cuff muscles are the supraspinatus, infraspinatus, teres minor, and subscapularis.
What attaches to AC joint?
The rotator cuff covers the head of the upper arm bone and attaches it to the shoulder blade. The AC (acromioclavicular) joint is formed where a portion of the scapula (acromion) and the clavicle meet and are held together by tough tissues (ligaments) that act like tethers to keep the bones in place.
Which muscle is the prime mover for shoulder flexion?
Pectoralis major is the muscle which acts as prime mover in shoulder flexion.
What are the agonist and antagonist muscles in shoulder flexion?
Agonist is deltoid, antagonist is the latissimus dorsi. As the muscles contract across the shoulder joint it brings your shoulder upward into flexion as you push the ball the opposite happens and the antagonist becomes your deltoid and the latissimus dorsi becomes your agonist.
What movements does the AC joint do?
The AC joint is a plane type synovial joint, which under normal physiological conditions allows only gliding movement. As it attaches the scapula to the thorax, it allows an additional range of motion to the scapula and assists in arm movement such as shoulder abduction and flexion.
What Stabilises the AC joint?
The AC joint is stabilized by the two sets of ligaments; A pair of intrinsic ligaments found within the articular capsule; the superior and inferior acromioclavicular ligaments. A single extrinsic ligament found outside the joint capsule; the coracoclavicular ligament.
What does the supraspinatus muscle do?
The supraspinatus muscle functions to initiate abduction and depress the humeral head against the upward pull of the deltoid. The muscle and tendon travel slightly obliquely from posterior to anterior, allowing it to contribute to external rotation as well.
What initiates shoulder flexion?
Posterior rotator cuff muscles appear to be counterbalancing anterior translational forces produced during flexion and it would appear that supraspinatus is one of the muscles that consistently “initiates” flexion.
What is the antagonist for shoulder flexion?
Which muscle is the antagonist to flexion of the arm at the shoulder?
Pectoralis major and latissimus dorsi act as antagonists. The middle region of the deltoid muscle is the prime mover for arm abduction.
What is AC joint in shoulder?
The acromioclavicular (AC) joint is formed by the cap of the shoulder (acromion) and the collar bone (clavicle). It is held together by strong ligaments (figure 1). The outer end of the clavicle is held in alignment with the acromion by the acromioclavicular ligaments and the coracoclavicular (CC) ligaments.
What stabilizes the AC joint?
Ligaments. The joint is stabilized by three ligaments: The acromioclavicular ligament, which attaches the clavicle to the acromion of the scapula.
What muscles attach to the acromion?
Two major muscles, the deltoid and trapezius, attach to the acromion. The deltoid, which abducts the arm at the shoulder, forms its origin along the acromion, the spine of the scapula, and the clavicle. From these origins, it crosses the shoulder joint and inserts on the deltoid tuberosity of the humerus.
Does supraspinatus flex the shoulder?
A study in 2011 used electromyography to study the levels of activity in the shoulder muscles during flexion, and found that supraspinatus was consistently recruited prior to movement of the limb at all loads; the authors concluded that “Posterior rotator cuff muscles appear to be counterbalancing anterior …