Forearm

Your forearm is between your elbow and wrist.

It has two long bones inside. These bones help you move. They also let you turn your hand. One bone lets your palm face down. The other lets your palm face up.

Many muscles live in your forearm. These muscles move your fingers and wrist. They also help move your elbow. Skin covers the whole area. Some parts have more hair than others. This part of your body is very busy!

The forearm is the part of your arm between the elbow and the wrist.

It contains two long bones. One is called the radius. The other is the ulna. A thin sheet called the interosseous membrane connects them.

Many muscles live in the forearm. Some muscles are flexors. These help you bend your wrist or fingers. Other muscles are extensors. These help you straighten them. Some muscles help you turn your hand. You can turn your palm down. This is called pronation. You can also turn your palm up. This is called supination.

Nerves and blood vessels also run through this area. The radial and ulnar arteries carry blood to the forearm. Several veins carry blood back.

Doctors sometimes use these veins to take blood.

Sometimes, the bones in the forearm can break. This is called a fracture. A person might break just the radius. They might break just the ulna. Or they might break both bones at once.

For children, doctors sometimes use a splint to help fix a break.

The forearm is the part of your upper limb between the elbow and the wrist.

In anatomy, people use the word arm to describe the whole limb. However, the word arm technically only means the part between the shoulder and elbow. This makes the forearm a very important and distinct section. It is like the part of your leg between the knee and the ankle. This area allows your hand to move and work in many ways.

Two long bones make up the structure of the forearm. These bones are called the radius and the ulna. The radius sits on the lateral side, which is the thumb side. The ulna sits on the medial side, near your body. A thin sheet called the interosseous membrane connects these two bones. At the elbow, the radius head meets the humerus and the ulna. At the wrist, these bones connect to the scaphoid and lunate bones.

Many muscles live inside the forearm to help you move. Some are called flexors because they bend your wrist or fingers. Other muscles are extensors that help you straighten them. You also have muscles that turn your hand. Turning your palm down is called pronation. Turning your palm up is called supination. The flexor muscles are often more massive than the extensors. This is because they work against gravity as anti-gravity muscles.

Nerves and blood vessels keep the forearm working well. The radial and ulnar arteries supply blood to the whole area. These vessels usually run along the front of the bones. There are also several veins like the cephalic and basilic veins.

Doctors sometimes use these veins to take blood samples. The ulnar nerve and the median nerve also run through the forearm. The radial nerve helps supply the muscles in the back part. These parts work together to keep your limb healthy and strong.

Sometimes, the bones in the forearm can suffer a fracture. A fracture is a break in the bone. You might break just the radius or just the ulna. Sometimes, a person might break both bones at once.

There are also rare conditions like hereditary multiple exostoses. This is a genetic disorder that affects bone growth. It can cause deformities in the radius and the ulna. For children with certain types of breaks, a splint might work better than a cast.

The forearm is the anatomical region located between the elbow and the wrist. In common language, people often use the word "arm" to describe the entire upper limb. However, in technical anatomy, the term "arm" refers only to the region between the shoulder and the elbow. This makes the forearm a distinct and essential section of the upper limb. It is considered homologous to the crus, which is the part of the leg between the knee and the ankle.

The structure of the forearm relies on two long bones: the radius and the ulna. The radius is located on the lateral side, which is the side of the thumb. The ulna is located on the medial side, closer to the body. These two bones are connected by a tissue called the interosseous membrane. At the elbow, the radius and ulna form the proximal radioulnar joint. The radius head connects to the capitulum of the humerus and the radial notch of the ulna. At the wrist, the radius connects to the scaphoid and lunate bones. The ulna also connects to the wrist to form part of the joint.

Muscles within the forearm are organized into two main fascial compartments. The posterior compartment contains the extensors, which are muscles that straighten the hand and fingers. These muscles are primarily supplied by the radial nerve. The anterior compartment contains the flexors, which are muscles that bend the wrist and digits. This compartment is mainly supplied by the median nerve, though the ulnar nerve also supplies some medial muscles. Interestingly, the flexor muscles are more massive than the extensors. This is because they act as anti-gravity muscles that work against the pull of gravity.

Muscles are further categorized as either intrinsic or extrinsic. Intrinsic muscles act directly on the forearm itself. They move the forearm across the elbow joint or the radioulnar joints. Extrinsic muscles act upon the hand and the wrist instead. Some muscles have unique roles, such as the brachioradialis. Although it is located in the posterior compartment, it is actually an anterior muscle that acts as a flexor of the forearm. Another muscle, the anconeus, is sometimes classified as part of the posterior compartment of the arm.

The movement of the forearm is controlled by several specific actions. The forearm can be flexed to bring it closer to the upper arm. It can also be extended to move it away from the upper arm via the elbow joint. Rotation is another key function of this region. This process is called pronation when the palm rotates to face downward. The opposite movement is called supination, where the palm rotates to face upward. These movements occur due to the interaction between the elbow and the distal radioulnar joint.

Blood and nerve signals are vital for forearm function. The radial and ulnar arteries, along with their various branches, supply blood to the region. These arteries typically run along the anterior face of the radius and ulna. For returning blood, the forearm has main superficial veins called the cephalic, median antebrachial, and basilic veins.

Medical professionals sometimes use these veins for venipuncture or cannularisation. While the cubital fossa is a preferred site for drawing blood, these forearm veins are also accessible. Nerves like the median, radial, and ulnar nerves travel through the area to control muscle movement.

Injuries to the forearm can be serious and vary in type. A fracture is a break in the bone that can involve only the radius, only the ulna, or both bones in a radioulnar fracture.

For children suffering from torus fractures, medical professionals may find that splinting works better than using a cast. There are also genetic conditions that can impact the forearm. Hereditary multiple exostoses is a disorder caused by growth disturbances in the epiphyses of the radius and ulna. This condition can lead to various deformities in the hand and forearm.