Elbow Anatomy Pleasanton | Orthopedic Surgery San Ramon | Tracy CA
The elbow is a complex joint formed by the articulation of three bones –the humerus, radius and ulna. The elbow joint helps in bending or straightening of the. Aug 12, The orientation of the bones forming the elbow joint produces a hinge type synovial joint, which allows for extension and flexion of the forearm. The elbow and the forearm are made up of only three bones and two joints. Half of the elbow is formed by the humerus, the lone bone of the arm. The forearm.
Muscles of the Elbow Joint There are several muscles extending across the elbow joint that help in various movements. These include the following: The elbow joint is supported by ligaments and tendons, which provide stability to the joint.
Ligaments are a group of firm tissues that connect bones to other bones. The most important ligaments of the elbow joint are the: Medial or ulnar collateral ligament: Lateral or radial collateral ligament: Together, the medial and lateral ligaments are the main source of stability and hold the humerus and ulna tightly in place during movement of the arm.
These are a group of fibers that surrounds the radial head, and holds the ulna and radius tightly in place during movement of the arm. The ligaments around a joint combine to form a joint capsule that contains synovial fluid.
The Elbow Joint
Any injury to these ligaments can lead to instability of the elbow joint. Other major structures of the elbow include: Ligaments Tough bands of connective tissue called ligaments hold the bones of the elbow together.
The two main ligaments connecting the humerus and ulna are: A third major ligament of the elbow is the annular ligament, which circles the top, or head, of the radius, holding it against the humerus. The ligaments form a capsule around the joint that is lined with a smooth membrane called the synovium. The synovium produces a viscous liquid, called synovial fluid, which lubricates the joint. Muscles Several muscles surround the elbow, making it possible for you to move your arm.
The Elbow Joint - Structure - Movement - TeachMeAnatomy
It originates on the scapula with two tendons: That of the long head on the supraglenoid tubercle just above the shoulder joint and that of the short head on the coracoid process at the top of the scapula. Its main insertion is at the radial tuberosity on the radius.
Brachialis is the main muscle used when the elbow is flexed slowly. During rapid and forceful flexion all three muscles are brought into action assisted by the superficial forearm flexors originating at the medial side of the elbow. Passive flexion is further limited by tension in the posterior capsular ligament and in triceps brachii. Triceps originates with two heads posteriorly on the humerus and with its long head on the scapula just below the shoulder joint.
It is inserted posteriorly on the olecranon. As the angle of flexion increases, the position of the olecranon approaches the main axis of the humerus which decreases muscle efficiency. In full flexion, however, the triceps tendon is "rolled up" on the olecranon as on a pulley which compensates for the loss of efficiency.
Because triceps' long head is biarticular acts on two jointsits efficiency is also dependent on the position of the shoulder. Forced extension results in a rupture in one of the limiting structures: The superior and inferior ulnar collateral branches of the brachial artery and the radial and middle collateral branches of the profunda brachii artery descend from above to reconnect on the joint capsule, where they also connect with the anterior and posterior ulnar recurrent branches of the ulnar artery ; the radial recurrent branch of the radial artery ; and the interosseous recurrent branch of the common interosseous artery.
The lymphatic drainage at the elbow is through the deep nodes at the bifurcation of the brachial artery, the superficial nodes drain the forearm and the ulnar side of the hand. The efferent lymph vessels from the elbow proceed to the lateral group of axillary lymph nodes. The order of appearance can be understood by the mnemonic CRITOE, referring to the capitellumradial headinternal epicondyle, trochleaolecranon, and external epicondyle at ages 1, 3, 5, 7, 9 and 11 years.
These apophyseal centers then fuse during adolescence, with the internal epicondyle and olecranon fusing last. The ages of fusion are more variable than ossification, but normally occur at 13, 15, 17, 13, 16 and 13 years, respectively.
In humans, the main task of the elbow is to properly place the hand in space by shortening and lengthening the upper limb. While the superior radioulnar joint shares joint capsule with the elbow joint, it plays no functional role at the elbow.
Additionally, the forearm muscles that originate at the elbow are grouped at the sides of the joint in order not to interfere with its movement. The deviation from a straight line occurs in the direction of the thumb, and is referred to as the "carrying angle" visible in the right half of the picture, right.
The carrying angle permits the arm to be swung without contacting the hips. Women on average have smaller shoulders and wider hips than men, which tends to produce a larger carrying angle i. There is, however, extensive overlap in the carrying angle between individual men and women, and a sex-bias has not been consistently observed in scientific studies. A more recent study based on a sample size of individuals from both sexes concluded that carrying angle is a suitable secondary sexual characteristic.
Developmental,  aging and possibly racial influences add further to the variability of this parameter. Lateral X ray of a dislocated right elbow Right: AP X ray of a dislocated right elbow The types of disease most commonly seen at the elbow are due to injury. Tendonitis[ edit ] Two of the most common injuries at the elbow are overuse injuries: