Muscles of pectoral girdle

Muscles of Pectoral Girdle

Overview

• The muscles of the pectoral girdle are essential for stabilizing and positioning the shoulder joint.

• They facilitate the movements of the arm.

• Divided into two groups: anterior muscles (front of the thorax) and posterior muscles (back of the thorax).

Anterior Muscles

Subclavius

• Location: Anterior thorax.

• Function: Stabilizes the clavicle by pushing it downward (depression).

• Origin: First rib.

• Insertion: Underside of the clavicle.

Pectoralis Minor

• Location: Anterior thorax.

• Function: Rotates the shoulder forward (important for throwing) and assists with inhalation.

• Movement: Affects the scapula by moving it down; elevates ribs.

• Origin: Anterior surfaces of ribs 2-4 or 3-5.

• Insertion: Coracoid process of the scapula.

Serratus Anterior

• Location: Anterior thorax.

• Function: Moves the arm from the side of the body to the front; assists with inhalation.

• Movement: Protracts scapula and elevates ribs.

• Origin: Muscle slips from ribs 1-8 or 1-9.

• Insertion: Anterior surface of the scapula's vertebral border.

Posterior Muscles

Trapezius

• Location: Posterior thorax.

• Function: Elevates shoulders (shrugging), pulls shoulder blades together, and tilts head backward.

• Movement: Affects scapula and cervical spine by retracting, elevating, and extending the spine.

• Origin: Skull and vertebral column.

• Insertion: Acromion and spine of the scapula; clavicle.

Rhomboid Major

• Location: Posterior thorax.

• Function: Stabilizes shoulder blade (scapula) during pectoral girdle movement.

• Movement: Retracts and rotates scapula downward.

• Origin: Thoracic vertebrae (T2-T5).

• Insertion: Medial border of the scapula.

Rhomboid Minor

• Location: Posterior thorax.

• Function: Also stabilizes shoulder blade during movement.

• Movement: Retracts and rotates scapula downward.

• Origin: Cervical and thoracic vertebrae (C7 and T1).

• Insertion: Medial border of the scapula.

Table of Muscles That Position the Pectoral Girdle

• Provides an overview of the primary muscles, their movements, origins, and insertions.

• Highlights their roles in the stabilization and movement of the shoulder.

Importance

• These muscles provide vital stability to the pectoral girdle.

• They enable a wide range of movements in the arm and shoulder, facilitating various physical activities and tasks.

Additional Resource

• Recommended video: "Shoulder (Pectoral) Girdle - Muscles and Movements" available through the provided link.