Deltoid muscle

The deltoid muscle ( AltGr δελτοειδής, " triangle -like", . " Deltoid " ), also briefly called the deltoid, is a triangular skeletal muscle. It is as a package via the shoulder joint and adds maintenance, by pushing the head of the humerus in the joint socket. The deltoid muscle is significantly involved in the contour of the shoulder region and is used to raise the arm.

Shares

The deltoid muscle can be divided humans into three parts:

• Clavicular ( collarbone part; " anterior deltoid " )
• Acromial ( shoulder height part; " middle deltoid " )
• Pars spinalis ( bones part; ; " posterior deltoid " )

In many mammals the clavicle is regressed and therefore the clavicular not formed. In animals without acromion (such as horses, pigs True ) and the acromial missing. The pars spinalis is called in veterinary anatomy as Pars scapularis (shoulder blade part).

Function

After initial abduction of the arm to about 10 degrees by the supraspinatus the deltoid pulls with its middle fibers ( pars acromialis ) the arm to about 60 degrees upward, before becoming active insufficient. Now, however, the feathered shares ( clavicular and spinal ) reach their required lift height and can thus abduct the arm further and elevieren ( about 90 degrees lift ). However, for the lifting of the arm above the horizontal plane (elevation) a rotation of the scapula necessary because otherwise the arm abuts against the acromion. The anterior fibers pull the arm in addition to the front ( flexion or anteversion ) and turn it to the inside ( medial), the posterior fibers, however, pull the arm backward (extension or retroversion ) and turn it to the outside ( lateral).

In the four-footed mammals in the muscle acts as a flexor of the shoulder joint.

Clinic

The deltoid muscle is used (large distance to nerves or arteries) for intramuscular injection of drugs due to its location. In paralysis of the axillary nerve to the deltoid falls as the most powerful abductor of the shoulder joint, the supraspinatus can not take on the task, and the raising of the arm is greatly reduced.