The Human Arm
The human arms serve many purposes, the most obvious of which is to allow us to move items around and do many every day activities in conjunction with using our hands. The human arm consists of a clavicle, Acromial end, Acromion process, Coracoid process, Deltoid tubercle, Humerus, Capitulum, Trochlea, Radial tuberosity, Semilunar notch Olecranon Process on the posterior side, Radius and an Ulna.
The clavicle is also commonly referred to as the collar bone and is a long bone which creates part of the shoulder girdle. This bone rotates along its axis like a key does when the shoulder is drawn away from the median plane of the body. In people, particularly those who have little fat in this area, the clavicle is easily visible as being a bulge in the skin close to the height of the shoulders.
The acromial end is the flat lateral end of the collar bone which works in conjunction with the acromion and is held in place to the coracoids process by ligaments shaped like trapezoids and the conoid.
The acromion process is also shortened to simply the acromion which means shoulder. This process is featured on the shoulder blade in conjunction with the coracoids process and extends over the shoulder joint in a lateral manner.
The coracoids process is a hook shape and is located on the lateral edge of the anterior section of the scapula. Pointing forward in a lateral sense it works with the acromion in order to provide stability to the shoulder joint. The coracoids process is palpable in the groove between the deltoid and the pectoralis major muscles which is known as the deltopectoral groove.
The deltoid tubercle is a prominence on the dorsum of the scapular spine which is located laterally to the root of the spine. A flat tendon shaped like a triangle from the least important section of the middle area of the muscle is attached to the deltoid tubercle.
The humerus is well known as the “Funny bone” and is a long bone located in the forearm which runs the length from the shoulder down to the elbow. This bone connects the scapula and the radius to one another and has three sections which are the upper extremity of humerus, the body of humerus and the lower extremity of humerus.
The capitulum in the human arm is the lateral section of the articular surface of the funny bone and is smooth and rounded. A depression in the shape of a cup on the head of the radius and the Capitulum work together and it is limited to the front bottom section of the bone.
The troclea is a grooved structure which is located in the medial section of the articular surface of the humerus. This is characterized as a deep depression between two well distinguished borders. The trochlea is convex from before backward and concave from side to side and occupies multiple areas such as the anterior, lower and posterior sections of the extremity.
The radial tuberosity is also referred to as the bicipital tuberosity. This is a bony marking which is the primary insertion of the brachii muscle of the bicep.
The olecranon and the coronoid process form a large depression which is known as the semilunar notch. Around the middle section of either side of the notch there is an indentation which causes it to somewhat contract and provides an indication of the junction of the olecranon and the coronoid process.
The bone in the forearm responsible for connecting the elbow to the forearm, which extends from the lateral side of the elbow right down to the wrist on the thumb side, is the radius. The radius bone rotates around an axis line which extends diagonally from the middle of the capitulum to the centre of distal ulna.
The ulna bone is long and prismatic and located at the medial side of the forearm and parallel to the radius on both arms.