Henry Gray (18251861). Anatomy of the Human Body. 1918.
binds the skin so firmly to the palmar aponeurosis that very little movement is permitted between the two.
On the back of the hand and fingers the subcutaneous tissue is lax, so that the skin is freely movable on the underlying parts. Over the interphalangeal joints the skin is very loose and is thrown into transverse wrinkles when the fingers are extended.
Bones.The clavicle can be felt throughout its entire length. The enlarged sternal extremity projects above the upper margin of the sternum at the side of the jugular notch, and from this the body of the bone can be traced lateralward immediately under the skin. The medial part is convex forward, but the surface is partially obscured by the attachments of Sternocleidomastoideus and Pectoralis major; the lateral third is concave forward and ends at the acromion of the scapula in a slight enlargement. The clavicle is almost horizontal when the arm is lying by the side, although in muscular subjects it may incline a little upward at its acromial end, which is on a plane posterior to the sternal end.
The only parts of the scapula that are truly subcutaneous are the spine and acromion, but the coracoid process, the vertebral border, the inferior angle, and to a lesser extent the axillary border can also be readily defined. The acromion and spine are easily recognizable throughout their entire extent, forming with the clavicle the arch of the shoulder. The acromion forms the point of the shoulder; it joins the clavicle at an acute anglethe acromial angleslightly medial to, and behind the tip of the acromion. The spine can be felt as a distinct ridge, marked on the surface as an oblique depression which becomes less distinct and ends in a slight dimple a little lateral to the spinous processes of the vertebræ. Below this point the vertebral border can be traced downward and lateralward to the inferior angle, which can be identified although covered by Latissimus dorsi. From the inferior angle the axillary border can usually be traced upward through its thick muscular covering, forming with its enveloping muscles the posterior fold of the axilla. The coracoid process is situated about 2 cm. below the junction of the intermediate and lateral thirds of the clavicle; it is covered by the anterior border of Deltoideus, and thus lies a little lateral to the infraclavicular fossa or depression which marks the interval between the Pectoralis major and Deltoideus.
The humerus is almost entirely surrounded by muscles, and the only parts which are strictly subcutaneous are small portions of the medial and lateral epicondyles; in addition to these, however, the tubercles and a part of the head of the bone can be felt under the skin and muscles by which they are covered. Of these, the greater tubercle forms the most prominent bony point of the shoulder, extending beyond the acromion; it is best recognized when the arm is lying passive by the side, for if the arm be raised it recedes under the arch of the shoulder. The lesser tubercle, directed forward, is medial to the greater and separated from it by the intertubercular groove, which can be made out by deep pressure. When the arm is abducted the lower part of the head of the humerus can be examined by pressing deeply in the axilla. On either side of the elbow-joint and just above it are the medial and lateral epicondyles. Of these, the former is the more prominent, but the medial supracondylar ridge passing upward from it is much less marked than the lateral, and as a rule is not palpable; occasionally, however, the hook-shaped supracondylar process (page 211) is found on this border. The position of the lateral epicondyle is best seen during semiflexion of the forearm, and is indicated by a depression; from it the strongly marked lateral supracondylar ridge runs upward.
The most prominent part of the ulna, the olecranon, can always be identified at the back of the elbow-joint. When the forearm is flexed the upper quadrilateral surface is palpable, but during extension it recedes into the olecranon fossa. During extension the upper border of the olecranon is slightly above the level of the medial