The anconeus is a small triangular muscle that originates just below the elbow joint at the lateral condyle of the humerus and extends a fourth of the way down the forearm to insert in the olecranon process and back of the ulna. It is located on the outer back corner of the elbow. The anconeus is innervated by the radial nerve and supplied by the radial artery. It extends and stabilizes the elbow joint. Research Anconeus
The arm is the upper limb in man, connected with the thorax or chest by means of the scapula or shoulder-blade, and the clavicle or collar-bone. It consists of three bones, the arm-bone (Humerus), and the two bones of the forearm (radius and ulna), and it is connected with the bones of the hand by the carpus or wrist. The head or upper end of the arm-bone fits into the hollow called the glenoid cavity of the scapula, so as to form a joint of the ball-and-socket kind, allowing great freedom of movement to the limb. The lower end of the humerus is broadened out by a projection on both the outer and inner sides (the outer and inner condyles), and has a pulley-like surface for articulating with the fore-arm to form the elbow-joint. This joint somewhat resembles a hinge, allowing of movement only in one direction. The ulna is the inner of the two bones of the fore-arm. It is largest at the upper end, where it has two processes, the coronoid and the olecranon, with a deep groove between to receive the humerus. The radius - the outer of the two bones - is small at the upper and expanded at the lower end, where it forms part of the wrist-joint. The muscles of the upper arm are either flexors or extensors, the former serving to bend the arm, the latter to straighten it by means of the elbow-joint. The main flexor is the biceps, the large muscle which may be seen standing out in front of the arm when a weight is raised. The chief opposing muscle of the biceps is the triceps. The muscles of the fore-arm are, besides flexors and extensors, pronators and supinators, the former turning the hand palm downwards, the latter turning it upwards. The same fundamental plan of structure exists in the limbs of all vertebrate animals. Research Arm
Bones (or osseous material) serve a number of diverse purposes in the human anatomy. In addition to providing structure, protection, and support for the organs of the body, bones also house marrow, which produces blood cells. Within the bones are also stored the calcium deposits which the body may access, via resorption, when needed. Additionally, bones detoxify the system, by removing heavy metals, such as lead and arsenic, as well as other toxins, from the bloodstream. Osseous tissue itself is made of water (about 1/4 of the bone weight), organic material (about 1/3 of the bone weight, most of which is the protein, ossein) and inorganic minerals (calcium, phosphorus, and magnesium predominate, though iron, sodium, potassium, chlorine, and fluorine are also present in small amounts). Most bones (with the exception of those of the skull) are initially pre-formed in cartilage and are then ossified as the newborn develops.
Two basic classification methods exist to categorize the bones of the body. These two classification systems are based upon anatomical location (axial or appendicular), and shape (long, short, flat, and irregular). Axial bones are the eighty bones which lie along the central, vertical axis of the body and support and protect the head and torso and include the skull and the spinal column.
Appendicular bones include the one hundred twenty-six bones which comprise the appendages, including the shoulders and hips, arms and legs, hands and feet, and fingers and toes. The shape classifications include long bones (such as the radius, humerus, and femur), the short bones (such as the carpals, tarsals, and manual and pedal phalanges), flat bones (such as the sternum, cranium bones, and scapulae), and irregular
bones (such as the vertebrae). Research Bone
The brachialis is a slender, flat muscle that lies under the biceps along the front of the lower half of the humerus and in front of the elbow joint. It originates from the front of the humerus and inserts in the coronoid process of the ulna. The brachialis is innervated by the musculocutaneous nerve and the radial nerve. It is supplied by the brachial artery and radial artery. This muscle protects the elbow, and helps flex and rotate the forearm. Research Brachialis
The brachioradialis (supinator longus) originates two-thirds of the way down the humerus between the triceps and the brachialis. The muscle begins wide and flat and twists toward the front of the arm as it descends. It then widens and flattens again before ending in a flat tendon, which inserts on the thumb side of the radius. It is innervated by branches of the radial nerve and supplied by radial recurrent artery. Unlike most of the long tendons of the forearm, the tendon does not cross the wrist joint, but rather ends at the distal end of the radius. This muscle bends the forearm at the elbow. It does not assist in turning the forearm. Research Brachioradialis
The capsular ligaments encircle the shoulder joint, forming the bulk of the shoulder join capsule. These ligaments are attached to the margin of the glenoid cavity and around the neck of the humerus. They are reinforced by the supraspinatus, the subscapularis, the infraspinatus, the teres minor, and the long head of the triceps. Research Capsular Ligaments
The coracobrachialis or 'Casser's perforated muscle' is the smallest muscle in the upper arm region. It originates from the coracoid process of the scapula and inserts in the medial border of the humerus. The coracobrachialis is innervated by the musculocutaneous nerve and supplied by the brachial artery. This muscle is a somewhat superficial muscle and can be partially seen on the inside of the upper arm near the arm pit when the arm is raised. It runs alongside, but separate from, the short head of the biceps brachii. It flexes and adducts the arm at the shoulder joint. Research Coracobrachialis
The coronoid fossa is a depression located on the lower end of the front of the humerus. It accepts the coronoid process of the ulna when the elbow joint is in flexion. Research Coronoid Fossa
The deltoid is a large, thick powerful muscle with a triangular form and a coarse texture. The muscle is divided into three portions: an anterior (clavicular) portion, and acrominal portion, and a posterior portion. The anterior portion forms the broad side of the muscle and the posterior portion is located on the back of the shoulder. The muscle originates from the clavicle and from the spine of the scapula covering the outer side of the shoulder joint, giving the shoulder its rounded appearance, and inserts in the humerus. The deltoid is innervated by the 5th and 6th cervical nerves through the circumflex nerve and supplied by the circumflex artery.
Almost any movement of the shoulder and upper arm involves the deltoid muscle. The anterior portion is used to raise the arm from the body and to lower it again. The acrominal portion is a powerful abductor and the posterior portion is used to move the arm backward. It works with the pectoralis major to move the arm forward and works with the teres major and latissimus dorsi to move the arm back. Research Deltoid
The humerus, radius, and ulna join to form the elbow joint. This joint features a number of complex prominences which serve as attachment sites of ligaments and muscles, serving to control the flexibility and adduction of the bones about the elbow. The articulation of the elbow is called a hinge joint, because, like a hinge on a door, the joint only permits flexion in a single plane. Research Elbow Joint
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Anconeus
