In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint and the elbow joint. The distal part of the upper limb between the elbow and the radiocarpal joint is known as the forearm or "lower" arm, and the extremity beyond the wrist is the hand.
The ulna or ulnal bone is a long bone found in the forearm that stretches from the elbow to the wrist, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of the forearm as the little finger. It runs parallel to the radius, the other long bone in the forearm. The ulna is longer and the radius is shorter, but the radius is thicker and the ulna is thinner. Therefore, the ulna is considered to be the smaller bone of the two bones in the lower arm. The corresponding bone in the lower leg is the fibula.
The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.
The brachioradialis is a muscle of the forearm that flexes the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm. It is attached to the distal styloid process of the radius by way of the brachioradialis tendon, and to the lateral supracondylar ridge of the humerus.
The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin.
The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is used to describe the entire appendage of the upper limb, but which in anatomy, technically, means only the region of the upper arm, whereas the lower "arm" is called the forearm. It is homologous to the region of the leg that lies between the knee and the ankle joints, the crus.
In human anatomy, extensor carpi radialis brevis is a muscle in the forearm that acts to extend and abduct the wrist. It is shorter and thicker than its namesake extensor carpi radialis longus which can be found above the proximal end of the extensor carpi radialis brevis.
In human anatomy, the extensor carpi ulnaris is a skeletal muscle located on the ulnar side of the forearm. The extensor carpi ulnaris acts to extend and adduct at the carpus/wrist from anatomical position.
In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.
Wrist drop is a medical condition in which the wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.
The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, prism-shaped and slightly curved longitudinally.
The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulder, elbow, wrist and knuckle joints. In humans, each upper limb is divided into the arm, forearm and hand, and is primarily used for climbing, lifting and manipulating objects.
The ulnar collateral ligament (UCL) or internal lateral ligament is a thick triangular ligament at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.
The cubital fossa,super pitchelidon or inside of elbow, is the area on the anterior side of the upper part between the arm and forearm of a human or other hormid animals. It lies anteriorly to the elbow when in standard anatomical position.
The flexor carpi ulnaris (FCU) is a muscle of the forearm that flexes and adducts at the wrist joint.
The lateral epicondyle of the humerus is a large, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow joint, and to a tendon common to the origin of the supinator and some of the extensor muscles. Specifically, these extensor muscles include the anconeus muscle, the supinator, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris. In birds, where the arm is somewhat rotated compared to other tetrapods, it is termed dorsal epicondyle of the humerus. In comparative anatomy, the term ectepicondyle is sometimes used.
The pronator teres is a muscle that, along with the pronator quadratus, serves to pronate the forearm. It has two origins, at the medial humeral supracondylar ridge and the ulnar tuberosity, and inserts near the middle of the radius.
In human anatomy, the supinator is a broad muscle in the posterior compartment of the forearm, curved around the upper third of the radius. Its function is to supinate the forearm.
The fascial compartments of arm refers to the specific anatomical term of the compartments within the upper segment of the upper limb of the body. The upper limb is divided into two segments, the arm and the forearm. Each of these segments is further divided into two compartments which are formed by deep fascia – tough connective tissue septa (walls). Each compartment encloses specific muscles and nerves.
The elbow is the region between the upper arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa, and the lateral and the medial epicondyles of the humerus. The elbow joint is a hinge joint between the arm and the forearm; more specifically between the humerus in the upper arm and the radius and ulna in the forearm which allows the forearm and hand to be moved towards and away from the body. The term elbow is specifically used for humans and other primates, and in other vertebrates forelimb plus joint is used.
