Humeral bone

Humeral bone – a skeletal basis of a shoulder, a long tubular bone.

Structure of a humeral bone

The humeral bone consists of a body and two epiphysis – distal lower and proximal upper.

In a lower part of a body of a bone there is a back surface limited on the periphery medial and lateral to edges, and also the lateral and medial front surfaces divided by slightly noticeable crest.

On a medial front body surface, is slightly lower than a middle part of a body, there is a nutritious opening conducting in distally the directed nutrient canal.

On a lateral front surface, is slightly higher than a nutritious opening, it is possible to see deltoid tuberosity – the place where the deltoid muscle fastens.

Behind deltoid tuberosity, on a back body surface, there passes the furrow of a beam nerve.

The proximal epiphysis is a little thickened. On it there is a semi-spherical head of a humeral bone turned up, inside and it is a little back. From other part of a bone the periphery of a head is limited to the small narrowing going annularly, a so-called anatomic neck. A little below it two hillocks – small and big are located. Down from each hillock last respectively a crest small and a crest of a big hillock. They are directed down and reach upper parts of a body of a bone. Together with hillocks they limit accurately expressed intergrumous furrow in which there is a sinew of a long head of a two-headed humeral muscle.

On border of a body and the upper end of a bone, is a little lower than hillocks, there is a surgical neck – the small narrowing corresponding to an epiphysis zone.

The distal epiphysis is squeezed in the perednezadny direction. Its lower part is called a condyle of a humeral bone. The condyle consists of a head to which the head of a beam bone, and the block which connects in an elbow joint to blokovidny cutting of an ulna connects.

In front of a distal epiphysis it is possible to see a coronal pole, over a condyle head – a beam pole, and on a back surface – a pole of an elbow shoot.

Peripheral departments of the lower part of a bone come to an end medial and lateral with epicondyles from which forearm muscles originate.

From each epicondyle lateral and medial epicondylic crests climb distal department respectively.

The medial epicondyle is stronger developed. On its dorsum it is possible to see a furrow of an elbow nerve, and in front there is a ledge – an epicondylic shoot with which the beam sgibatel of a wrist begins.

The furrow of an elbow nerve and epicondyles are well probed under skin and serve as bone reference points.

Fractures of a humeral bone

There are following types of fractures of humeral bone:

• Head change;
• Intra articulate change (fracture of an anatomic neck);
• Extraarticular changes (chrezbugorkovy fracture and fracture of a surgical neck);
• Change of a hillock of a humeral bone.

Changes of a head and anatomic neck of a bone arise, as a rule, as a result of direct stroke to the outside surface of a shoulder joint, or as a result of falling on an elbow joint. At the same time the head of a bone breaks up into several parts.

The clinical picture of a change is characterized by emergence of sharp pain. At the expense of hypostasis the shoulder joint increases, there is no opportunity to make the active movements by a hand. The passive movements are painful.

Fractures of a surgical neck of a humeral bone divide on abduction (taking-away) and adduktsionny (bringing).

The Adduktsionny fracture of a neck of a humeral bone arises preferential when falling with the emphasis on the extended given hand, and abduction – when falling with the emphasis on the extended taken-away hand.

At a fracture of a neck of a humeral bone without shift the patient feels the localized pain which at axial loading amplifies. At the same time function of a shoulder joint is limited.

At a change with shift the patient feels sharp pain and pathological mobility. Function of a shoulder joint is broken, the axis of a shoulder is broken and shortened.

The change of a hillock of a humeral bone most often occurs at dislocation of a shoulder or at the indirect mechanism of an injury. The change results from reflex reduction small round, podostny and supraspinal muscles. The isolated change of a hillock of a humeral bone without shift, as a rule, results from a shoulder bruise.

At a change patients feel the localized pain, there is hypostasis of soft tissues. The active movements cannot be carried out.