Elbow

The elbow joint is a hinge or hinge joint. It has three joints: humerus-ulnar, between the trochlea of the humerus and the trochlear notch of the ulna, humerus-radial, between the humeral capitulum and the head of the radius, and proximal radio-ulnar, between the head of the radius and the radial notch ulna.

The articular surfaces are joined by a capsule that is thickened medially and laterally by the ulnar and radial collateral ligaments.

Articular Capsule – It surrounds the entire joint and is formed by two parts: anterior and posterior. The anterior part is a thin fibrous layer that covers the anterior surface of the joint. The posterior part is thin and membranous and consists of oblique and transverse fibers.

Ulnar Collateral Ligament – It is a thick triangular bundle consisting of two portions: anterior and posterior, joined by a thinner intermediate portion.

Radial Collateral Ligament – It is a triangular fibrous bundle, less evident than the ulnar collateral ligament.

The proximal radioulnar joint is a trochoid or pivot joint between the circumference of the head of the radius and the ring formed by the radial notch of the ulna and the annular ligament.

Annular Ligament – It is a strong bundle of fibers that surrounds the head of the radius, keeping it in contact with the radial notch of the ulna.

From the inferior border of the annular ligament, a thick bundle of fibers extends to the neck of the radius, called the quadratus ligament.

ANTERIOR VIEW OF JOINT STRUCTURES OF THE ELBOW

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.

SIDE AND MEDIAL VIEW OF THE JOINT STRUCTURES OF THE ELBOW

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.

ANTERIOR AND POSTER VIEW OF JOINT STRUCTURES OF THE ELBOW

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.