Musculocutaneous nerve, radial nerve innervation

Musculocutaneous innervation

radial nerve

Radial nerve, median nerve innervation

Extend behind the upper arm to straighten or extend that arm

Located on the lateral side from the lateral epicondyle of the humerus to the proximal end of the ulna, although small, it provides stability to the axial and medial extension of the elbow joint and to the lateral side during extension.

pronator teres

pronator quadratus

flexor carpi radialis

Palmaris longus muscle

Biceps

supinator

carpi radialis muscle

pollicis longus muscle

index finger extensor muscles

The trochlear notch of the ulna joins the trochlea of ​​the humerus and has a corresponding matching shape. It is the main factor in the stable structure of the elbow joint.

Flexion and extension movements of the elbow joint occur on the medial-lateral axis of rotation passing through the lateral epicondyle

The elbow joint naturally extends in the frontal plane, and the angle formed by the longitudinal axis of the ulna and the longitudinal axis of the humerus is called cubital valgus or carrying angle. When the elbow joint is fully extended, the normal carrying angle is about 15°±5°, and women generally have about 5° more than men.

The anterior fiber bundle of the medial collateral ligament is the strongest and toughest fiber bundle

All fiber bundles of the lateral collateral ligament and the posterior lateral surface of the joint capsule oppose the force in the varus direction and stabilize the joint surface.

The ligaments surrounding the elbow joint contain mechanoreceptors

humeroradial joint

Humeroulnar joint

The radius and ulna need to be joined together through the interosseous membrane and the upper and lower radioulnar joints

In an anatomical position, with the forearm fully supinated, the ulna and radius are parallel

The annular ligament is a thick annular connective tissue band at the superior radioulnar joint.

The annular ligament of the inferior radioulnar joint is a thickened part of the fibrous bundle that continues the deep fascia of the forearm at the wrist.

The articular disc of the distal radioulnar joint is also called the triangular fibrocartilaginous disc

The neutral position of forearm rotation is the thumb-up position, which is the intermediate position between full pronation and supination.

Forearm pronation is approximately: 75° and supination is approximately 85°

The anterior interosseous membrane is a tendinous fibrous tissue that runs obliquely from the radius to the ulna, forming an elastic hinge between the ulna and the radius.

The main fiber orientation of the interosseous membrane cannot antagonize the tensile stress distal to the radius.