Muscle Origins, Insertions, and Actions – Rectus Abdominus, Teres Major, Quadratus Lumborum

Fifteen question-and-answer flashcards covering the origins, insertions, and key actions of the Rectus Abdominus, Teres Major, and Quadratus Lumborum muscles.

What is the origin of the Rectus Abdominus muscle?

The pubic crest.

Where does the Rectus Abdominus insert?

Into the cartilage of ribs 5–7 and the xiphoid process.

Which two primary actions are produced by the Rectus Abdominus?

1) Flexes the vertebral column, 2) Tilts the pelvis posteriorly.

What is the origin of the Teres Major muscle?

The inferior and lower one-third of the lateral border of the scapula.

Where is the insertion point of the Teres Major?

The crest of the lesser tubercle of the humerus.

Name the three actions performed by the Teres Major.

It extends, adducts, and medially rotates the shoulder.

What is the origin of the Quadratus Lumborum?

The posterior iliac crest.

Where does the Quadratus Lumborum insert?

Onto the last rib and the transverse processes of L1–L4.

List the two primary actions of the Quadratus Lumborum.

1) Laterally tilts the pelvis, 2) Laterally flexes the vertebral column.

Which muscle flexes the vertebral column and also tilts the pelvis posteriorly?

The Rectus Abdominus.

Which muscle extends, adducts, and medially rotates the shoulder joint?

The Teres Major.

Which muscle laterally tilts the pelvis and laterally flexes the lumbar spine?

The Quadratus Lumborum.

Into which specific costal cartilages does the Rectus Abdominus insert?

The costal cartilages of ribs 5, 6, and 7.

The crest of the lesser tubercle of the humerus serves as the insertion site for which muscle?

The Teres Major.

The posterior iliac crest is the point of origin for which lumbar muscle?

The Quadratus Lumborum.