RESULTADOS

Deltopectoral node

Axillary nodes (along axillary vein)

Cephalic vein

Basilic vein

Cubital nodes

Median cubital vein

Cephalic vein

Basilic vein

Vessels passing to dorsum of hand

Vessels passing around web to dorsum of hand Vessels passing to dorsum of fingers Vessels passing to dorsum of hand

Note: Arrows indicate direction of drainage

L

D

lateral, pectoral, and subscapular groups. Their efferent channels pass to the apical nodes.

The apical group, consisting of 6 to 12 nodes, lies along the axillary vein at the apex of the axilla and adjacent to the superior border of the pectoralis minor muscle. The apical nodes receive efferent vessels of all other axillary groups, lymphatic vessels that accompany the cephalic vein, and lymphatic vessels from the mammary gland. From lymph vessels interconnecting the apical nodes arises a larger common channel, the subclavian lymphatic trunk.

Deep Lymphatics

These vessels serve the upper limb, draining joint capsules, periosteum, tendons, nerves, and, to a lesser extent, muscles. Collecting vessels accompany the major arteries, along whose paths lie small intercalated lymph nodes. The deep lymphatics are afferent to the central and lateral axillary nodes.

SUPERFICIAL VEINS

The subcutaneous veins of the limb are interconnected with the deep veins of the limb via perforating veins.

Certain prominent veins, unaccompanied by arteries, are found in the subcutaneous tissues of the limbs. The cephalic and basilic veins, the principal superficial veins of the upper limb, originate in venous radicals in the hand and digits.

Anastomosing longitudinal palmar digital veins empty at the webs of the fingers into longitudinally oriented dorsal digital veins. The dorsal veins of adjacent digits then unite to form relatively short dorsal metacarpal veins, which end in the dorsal venous arch. The radial continuation of the dorsal venous arch is the cephalic vein, which receives the dorsal veins of the thumb and then ascends at the radial border of the wrist. In the forearm, it tends to ascend at the anterior border of the brachioradialis muscle, with tributaries from the dorsum of the forearm. In the cubital space, the obliquely ascending median cubital vein connects the cephalic and basilic veins. Above the cubital fossa, the cephalic vein runs in the lateral bicipital groove and then in the interval between the deltoid and pectoralis major muscles, where it is accompanied by the small deltoid branch of the thoracoacromial artery. At the deltopectoral triangle, the cephalic vein perforates the costocoracoid membrane and empties into the axillary vein. An accessory cephalic vein passes from the dorsum of the forearm spirally laterally to join the cephalic vein at the elbow.

The basilic vein continues the ulnar end of the venous arch of the dorsum of the hand (see Plate 4-17). It ascends along the ulnar border of the forearm and enters the cubital fossa anterior to the medial

epicondyle of the humerus. After receiving the median cubital vein, the basilic vein continues upward in the medial bicipital groove, pierces the brachial fascia a little below the middle of the arm, and enters the neu-rovascular compartment of the medial intermuscular septum, where it lies superficial to the brachial artery.

In the distal axilla, it joins the brachial veins to form the axillary vein.

The median antebrachial vein is a frequent collecting vessel of the middle of the anterior surface of the forearm. It terminates in the cubital fossa in the median cubital vein or in the basilic vein. It sometimes divides into a median basilic vein and a median cephalic vein, which borders the biceps brachii laterally and joins the cephalic vein. The median antebrachial vein may be large or absent.

F ASCIA AND S UPERFICIAL

A NATOMY OF THE H AND

(Continued)

D IGITS

The specializations of the fingers frequently have clini-cal importance. The bones, joints, and tendon attach-ments of the fingers have already been described. It remains to add other specific items of interest or impor-tance (see Plate 4-18).

NAILS

The fingernail is an approximately rectangular horny plate, the nail plate, composed of closely welded, horny scales, or cornified epithelial cells. Its semitransparency allows the pink of the highly vascular nail bed to show through. The nail is partially surrounded by a fold of skin, the nail wall, and adheres to the subjacent nail bed where strong fibers pass to the periosteum of the distal phalanx, providing the firm attachment necessary for the prying and scratching functions of the nail. The nail is formed from the proximal part of the nail bed, where the epithelium is particularly thick and extends as far distally as the whitened lunula. Developing from this nail matrix, the nail moves out over the longitudinal dermal ridges of the nail bed at a growth rate of approx-imately 1 mm/wk. Sensory nerve endings and blood vessels are abundant in the nail bed.

ANTERIOR CLOSED SPACE

To the palmar aspect of the distal phalanx lies the ante-rior closed space. Areolar tissue of mixed forms lies in this region. Fiber bundles surround fatty collections and support the finer arterial and nerve branching.

Epiphysis Nail matrix Nail root

Synovial membrane Articular cartilage

Middle phalanx

Extensor mechanism Lateral band

Eponychium (cuticle) Lunule Nail bed Nail plate Sagittal section

Flexor digitorum superficialis tendon Central tendon

Fibrous tendon sheath of finger Synovial (flexor tendon) sheath of finger

Flexor digitorum profundus tendon Palmar ligament (plate)

Articular cavity Nerves Arteries Septa

Distal phalanx

Distal anterior closed space (pulp)

Nail plate Nail bed Distal phalanx

Fibrous septa and areolar tissue in anterior closed space (pulp)

Dorsal digital artery and nerve Metacarpal head Subungual space

Minute arteries Fine nerves Cross section

through distal phalanx

Dorsal branches of palmar digital arteries and nerves to dorsum of middle and terminal phalanges Arteries and nerves

Nutrient branches to metaphysis

Nutrient branch to epiphysis Palmar digital artery and nerve

Palmar digital artery to neighboring digit

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: F

More discrete septa of connective tissue fibers pass from the periosteum of the distal phalanx to blend with the underside of the dermis. An especially abundant collection of fibers attaches to form the distal skin crease of the finger and thus serves to bound the ante-rior closed space of the finger pad. More proximally at the level of the proximal and distal interphalangeal joints the palmar skin is held fast by Cleland and Grayson ligaments during flexion and extension.

SMALL ARTERIES OF DIGITS

The general origin and distribution of the dorsal and palmar digital arteries have been fully discussed (see Plate 4-18), and it has been emphasized that the palmar digital arteries are the major arteries, since they send dorsal terminal branches over the distal and middle phalanges to supply the dorsum of the fingers and thumb. The dorsal digital arteries are poorly developed, except in the thumb. The proper palmar arteries are not

Flexor pollicis longus tendon Distal phalanx

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: T

Joint capsule

Proximal phalanx Sesamoid

Extensor pollicis brevis tendon Metacarpal

Flexor digitorum profundus and flexor digitorum superficialis tendons to index finger

Joint capsule

Trapezium Thenar mass

Extensor indicis and extensor digitorum tendons

Proximal phalanx thumb Ulnar collateral

ligament Radial collateral

ligament

Metacarpal 3 (long) Extensor expansion

Extensor expansion (hood) Metacarpal 2 (index)

2nd dorsal and 1st palmar interosseous muscles

1st dorsal interosseous muscle

Extensor pollicis longus tendon Flexor pollicis

longus tendon

Proximal palmar plate

A2 pulley Flexor digitorum

profundus and flexor digitorum superficialis tendons 1st lumbrical muscle 2nd lumbrical muscle

Sagittal view

Axial view

necessarily of equal size on the two sides of the digit, although they are essentially so for the middle and ring fingers. However, in the thumb and the index and fifth digits, the larger artery is on the median side of the digit; the more diminutive artery is on the opposite side.

These proper palmar digital arteries have cross anas-tomoses or transverse interconnections. There is a pair of proximal transverse digital arteries that anastomoses at the level of the neck of the proximal phalanx; a pair of distal transverse digital arteries also anastomoses at the level of the neck of the middle phalanx. These arter-ies run close to the bone and deep to the flexor tendons.

There is a rich terminal anastomosis of the palmar digital arteries, which forms a profuse tuft of small vessels in each finger pad. The proximal edge of this tuft of vessels lies on the palmar surface of the distal phalanx at about its epiphyseal line.

DIGITAL NERVES

The cutaneous nerves parallel the arteries in course and distribution. In their course along the fingers, the proper digital nerves are outside the arteries; that is, as the digit is viewed from the side, the arteries are within the span of the dorsal and palmar nerves. Cutaneous nerves are of two types. Included are afferent somatic fibers mediating general sensation (pain, touch, pres-sure, and temperature), and efferent autonomic fibers supplying the smooth muscles, sweat glands, and seba-ceous glands.

Both free and encapsulated nerve endings are involved in various sensations. Of the encapsulated endings, the Meissner tactile corpuscles are richly represented in the dermal papillae, and pacinian cor-puscles lie in the subcutaneous connective tissue, especially along the sides of the digits and are quickly adapting receptors responsible for moving touch (tested by moving two-point discrimination).

The slowly adapting receptors (Merkel cell neurite

complexes and Ruffini end organs) respond to static touch (measured by static two-point discrimination or with Semmes-Weinstein monofilament testing). The relatively large size of the proper palmar digital nerves suggests the high density of nerve endings in the fingers, especially in the finger pads. The tactile corpuscles are most numerous in the fingertips, less so on the palm, and rare on the dorsum of the fingers or hand.

D IGITS (Continued)