Question: Which 2 muscles laterally rotate the arm humerus at the shoulder joint?

The infraspinatus and teres minor both aid in lateral, or external, rotation of the arm at the shoulder.

What 2 muscles laterally rotate the humerus?

Infraspinatus: Originating at the infraspinous fossa of the scapula, this muscle inserts into the greater tubercle on the humerus. It laterally rotates the humerus.

Which muscles of the shoulder girdle laterally rotate the humerus?

Infraspinatus

  • Function: Lateral rotation of the arm, stabilize glenohumeral joint.
  • Origin: Infraspinous fossa.
  • Insertion: Greater tubercle of humerus, between the supraspinatus and teres minor insertion.
  • Innervation: Suprascapular nerve (C5, C6)

What is the humerus rotated laterally by?

External or lateral rotation of the arm represents the movement of the humerus when an arm flexed to 90° at the elbow is externally rotated around the longitudinal plane of the humerus such that the hand moves away from the midline of the body. It is the opposite of arm internal rotation.

Which muscle supports the arm in a position of 90 degrees of abduction?

The trapezius and serratus anterior muscles work in tandem to coordinate rotation and movement of the scapula to accommodate the full range of motion of the arm. Specifically, they facilitate abduction of the arm from 90 degrees and further upwards.

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What are the two main muscles that act on the elbow and shoulder?

Biceps Brachii – Attachments, Action & Innervation

Biceps brachii is one of the main muscles of the upper arm which acts on both the shoulder joint and the elbow joint.

What are the 3 shoulder joints?

The shoulder is made up of three bones: the scapula (shoulder blade), clavicle (collarbone) and humerus (upper arm bone). Two joints in the shoulder allow it to move: the acromioclavicular joint, where the highest point of the scapula (acromion) meets the clavicle, and the glenohumeral joint.

Which muscles of the anterior arm attach to the humerus?

Coracobrachialis: The coracobrachialis lies within the two heads of the biceps brachii. Attachments: Originates from the scapula and attaches to the humerus. Action: Flexing of the arm at the shoulder, and weak adduction.

What muscles are responsible for external rotation of the shoulder?

The infraspinatus muscle abducts and externally rotates the shoulder; it works best as a rotator with a patient’s prone position, and it is considered a pennate muscle. The teres minor muscle externally rotates the shoulder; It is considered a fusiform muscle.

What are the three muscles responsible for lateral rotation of the shoulder?

The infraspinatus and teres minor both aid in lateral, or external, rotation of the arm at the shoulder.

What muscles distally attach to the greater tubercle of the humerus?

Muscle Attachments

Muscle Attachment
Infraspinatus Greater Tubercle
Teres Minor Greater Tubercle Upper Part of the Lateral Border
Subscapularis Lesser Tubercle
Pectoralis Major Upper Part of the Anterior Border
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