Humerus

Head

At the upper end of the humerus is his head (caput humeri ), which enters with a roughly spherical joint surface connects to the shoulder blade (scapula, specifically the glenoid cavity ) and thus forms the shoulder joint. The head is flanked by two bony prominences ( greater tuberosity and lesser tuberosity = large = small ). The big advantage is the side ( lateral) of the humeral head. His directed cephalad ( cranial ) surface is rounded and has three flat impressions, where down below from the top muscles attach, which are collectively referred to as the rotator cuff: supraspinatus, infraspinatus and teres minor muscle. The lateral surface of the large protrusion is rough and convex curved outward and goes without visible limit on the shaft.

The small protrusion is indeed smaller than the large, but jumps more prominent to the front ( frontal). He shows also in the direction of pull - to the middle ( medial) - the tendon of the subscapularis muscle, he serves as an approach.

Between the projections a groove ( bicipital groove ), through which the long tendon of the biceps brachii and a branch of the anterior humeral artery ( circumflex humeral anterior) passes. In the domestic horse is in this groove, another bump ( tuberculum intermedium ). The trough pulls away from the body (distal ) to about the beginning of the middle third of the bone shaft, losing more and more expression. On both sides of the trough are two bone combs ( Crista tuberculi majoris and Crista tuberculi minoris ), which arise from the bony prominences.

Neck

If one follows the humerus further down, closes immediately below the head of the opposite of the joint surface easily retracted neck on ( anatomical neck ). It serves the joint capsule of the shoulder joint as an approach. Of it is defined, a second neck ( surgical neck ), a surgically significant weak point of the humerus, which is below the bony prominences in the transition to the shank.

The anterior, lateral surface (facies anterior lateralis) is part rounded smooth and close to the body ( proximal). It is covered by the deltoid muscle, the approach is located approximately in the center of the surface in a roughened ( deltoid tuberosity ). Beneath him is one of the rear surface (facies posterior) coming gutter ( sulcus radialis ) in which a nerve ( radial nerve ) and an artery (arteria profunda brachii ) diagonally from the rear - Swivel top forward, at this point are often trapped. In the distal part of the anterior, lateral surface serves as the origin of the musculus brachialis.

The front, center surface (facies anterior medial ) has a lower extent than the anterior, lateral surface. Its upper portion is narrow, forms the bottom of the trough between the projections ( bicipital groove ) and serves as the latissimus dorsi approach. A rough spot in the middle section is the approach of the musculus coracobrachialis. The distal part serves as the origin of the musculus brachialis.

The front edge ( anterior border ) runs from the front of the large projection bone down to a pit ( coronoid fossa ), and thereby separates, the front lateral surface of the front, central face. In the upper part it is a prominent bony ridge ( Crista tuberculi Majoris ), which serves as an approach to the pectoralis major muscle. In the middle it takes the front border of the deltoid - to roughening. Body distance they appear smooth and rounded and serves as the origin of musculus brachialis.

The lateral edge ( lateral margin ) moves from the back of the large bony prominence on top of the side Gelenkknorrens ( lateral epicondyle of the humerus ), thereby separating the front, side surface of the rear surface. The upper half is rounded and difficult to distinguish. It serves as an approach to the teres minor and far from the body of which brachii as the origin of the lateral head of the triceps. In the middle it is crossed by the flat bones Impression of the sulcus radialis. On the downside, it ends in a pronounced bony ridge ( Crista supracondylar lateralis), which serves the musculus brachioradialis as the origin.

The central edge ( medial border ) extends from small bony prominence to the top of the central Gelenkknorrens ( medial epicondyle of the humerus ). In the top third she appears as a prominent bony ridge ( Crista tuberculi minoris ). This is where the tendon of the teres major. In the middle it has a slight depression for the insertion tendon of the musculus coracobrachialis. The lower third rises to a - with increasing proximity to the attachment of the central Gelenkknorrens becoming clearer - bony ridge ( crista medial supracondylar ).

The lower end of the humerus is in front - flattened posterior direction and carries a condyle ( humeral condyle ), the ( articular facies) with its joint surfaces to spoke ( radius) and Elle ( ulna ) forms the elbow joint. Side and in the middle of the Gelenkknorrens each forms an attachment ( the lateral epicondyle and medial epicondyle ).

The central tower of the Gelenkknorrens is stronger pronounced than the lateral. Form- he sits in the central bar above the condyles continue. He serves as the approach surface of the side yard ribbon ( ulnar collateral ligament ). The central tower of the Gelenknorrens is the common origin of the superficial flexors of the forearm: pronator teres, flexor carpi radialis, flexor carpi ulnaris, palmaris longus and the flexor digitorum superficialis. The ulnar nerve runs in a bony canal on the rear side of the central tower of the Gelenkknorrens.

The lateral portion of the articular surface consists of a button-like rounded and distinctly protruding cartilage surface ( capitellum ). She stands with the curved inward ( concave ) articular surface of the condyle spokes (caput radii ) in combination ( articulated ). Equal to the body of the bulging cartilage surface one sees a recess ( fossa radialis ). She takes on the leading edge of the spoke little head when the forearm is placed in a strong flexion (flexion ).

Form the joint role can be seen in the front view of a small depression ( fossa coronoid ). She takes - similar to the well for the spoke head - the raven beak -like projection ( coronoid process ) Elle flexed forearm.

On the back of the upper arm bone of the joint role is located close to the body a more clearly pronounced triangular depression ( olecranon fossa ). She takes in the extended position of the forearm the olecranon, or more precisely the processus anconeus of the ulna on.