Drawing Bones On Your Hand

Anatomyand Structure

When the artist studies human anatomy, he is not usually pursuing the same goals as the medical doctor or the scientist. He is searching for visual form which can be translated aesthetically and augmented imaginatively. However, knowledge o! anatomy is essential for an understanding of various attitudes, postures, and movements. It allows the artist to truly understand the surface contours of the body because he knows the forms and structures underneath. It also teaches him why the surface forms appear as they do. Hopefully you will not be so caught in the study of the parts that you forget the rhythmic and unified whole. As you go through this chapter, you'll see the efficiency, order, and symmetry of the forms of the hand and the integrated way in which all work together to give the hand its wide variety of movement and response.

WRIST AND HAND BONES

The dorsal side of the hand, including the wrist, has a particularly bony surface, with many protrusions lying just under the skin. The band begins above the wrist at the point where the radius (A) and uirui (B) form the pivotal rtidio-ulnar joint. Note that only the radius articulates w ah the three top wrist bones (carpal bones) to form the radio-carpal joint (X).

Below the radio-carpal joint, the eight compact wrist bones as a unit make up the carpus, formed in a close-set ellipse, as seen in the schematic at right. Individually, they are known as carpah, andcachhasa separate name. The central lunate bone (C) tends to elevate the upper tier composed of the scaphoid bone (D)t a boat-shaped form on the inside; the moon-shaped lunate bone; the wedge-shaped triquetrum bone on the outside (E>; and the pea-shaped pisiform bone (F Four larger carpals make up the lower tier. Articulating directly with the thumb is the saddle-shaped trapezium bone fG)\ contacting the index finger is the boot-shaped trapezoid bone (H)\ next, the ke> stone shaped capitate bone (/>; outside, the hooked hamate bone (J).

Attached to the carpals arc the metacarpals (collectively called the metacarpus). These bones of the palm have no

individual names but arc simply identified by number. The thumb is the first metacarpal, the index finger, the second metacarpal, and so on. They have characteristics of long bones, with a shaft and two ends, the upper end articulating with the carpals and the lower end attaching to the phalanges or finger bones. The carpals and metacarpals form the palm and arc greatly limited in movement, since they arc bound closely at their bases by the metacarpal ligaments (AT) and at their heads by the intermetacarpal ligaments (L). The exception to this is the first metacarpal of the thumb. It is attached to the trapezium by a capsular ligament only, which allows it much wider activity than the other four.

Attached to the metacarpal bones are the phalanges, or fingers, of the hand. Each finger is called a phalanx, and each phalanx has three units—the proximal phalanx (St J, the medial phalanx (¡Vj, and the terminal phalanx (Oh The thumb again is the exception, having no medial phalanx. The terminal phalanx has a horny, shell-like substance emerging from it called the un^i/ii iP) or fingernail. Two tiny bones scarcely worth mentioning, almost blended with the ligaments and surface tissue, are the sesamoid bones lying on the lower mside surfacc of the first metacarpal of the thumb.

SKELETON IN ACTION

These two drawings show the bones of the wrist and hand in action. Note the limited movement of the carpais and metacarpals as compared to the wide range possible in the phalanges. The carpals in the lower sketch seem capable of only a slight rocking motion . As you sketch the information here, remember it is nol the bones of the hand that are the objcct of your drawing. They arc only underpinnings for the draw ing in an active, dynamic phase, with fingers flexed or extended, knuckles developed, and the whole charged with vital energy-

MOVEMENT POSSIBLE

Beginning at the radiocarpal joint (A) the hand can move back and forth (from front to back), from side to side, and at intermediate or oblique angles, either side to side or front to back. This last possibility allows the hand to swivel or rotate. Note that the ulna is not involved in this movement, since only the radius is in contact with the carpals, Uccausc the carpal bones arc joined very closely, only a gliding motion can occur, however, as noted in the previous drawing, a slight rocking forward and backward is possible bccause of the curse of the two tiers.

The large hand shown here is drawn with light and dark areas. The whst bones and the finger bones from the second joint down are accented, as are the base joints of the four metacarpal (palm) bones. AH other areas are kept light. The darker areas show the forms and joints which perform a limited movement; the lighter areas delineate forms which have freer movement.

The four long metacarpal bones attached to both wrist bones and intermetacarpals are so constrained by the intermetacarpal ligaments (B) that movement between them is negligible. The exception is the high thumb joint at the trapezium wrist bone (C), which is capable of much more freedom since no ligament controls it. The inierphalangeal joints tD. E) on the middle and terminal forms of the fingers, darkened with transverse arrows on the full-hand drawing, are capable of only forward and backward movement.

Note m the action sketch of the thumb at upper left that the characteristic movement of the distal phalanx of the thumb is toward and away from the palm. This movement is the same for all phalanges of the other four fingers, as shown in the action draw ing below. From the middle to the end joints, they can perform only a hinge movement.

SUMMARY OF FORMS

These drawings summarize (he forms discussed up (o this point and the activities of which they are capable. These are (he radiocarpal joint (A). the metacarpophalangeal joints from palm to finger (li), the wrist'thumb connection, (he carpometacarpal pint (CK and the intra-phalangeal digibto-digil joints ([)}. Each >s capable of performing to a greater or lesser degree circular gyration, compression and extension backward and forward. and swinging or rocking from side to side. Study (he drawings and use your own hand to discover the possibilities.

Note the arched arrangement of the carp*Is %hown in the rear views. This concavity is formed by a transverse ligament (E) attached to the pisiform (F> and the hook of the hamate IGJ at the outside and the crest of the trapezium (//) and the scaphoid (I) on the inside. Externally this ligament is not visible, but i(s function is to maintain the dome shape of the palm. You'll sec this tf you place your palm on a flat surface. You cannot flatten the palm center even if you press down.

RIGHT HAND, DORSAL VIEW

10, 1NTERPH AL ANGEAL WEBBING

11 FINGERS:

FIRST. POLLEX (THUMB)

SECOND. INDEX

THIRD. MED I US (MIDDLE)

FOURTH, DIGITUS ANNULARIS (RING)

FIFTH. DIGITUS MINIMUS (LITTLE)

\2 MNGER PADS. PALMAR SURFACE

!3. ABDUCTOR POLLICIS LONGUS

14. EXTENSOR POLL1CIS BREVLS

15 STYLOID PROCESS OF RADIUS

16 TENDON OF EXTENSOR POLUCIS LONGUS

17. ORIGIN OF EXTENSOR CARPI RADIALIS LONGUS

IS BASE OF METACARPAL II

19 DORSAL tNTEROSSEUS MUSCLES

20 ADDUCTOR POLLICIS TENDON OF EXTENSOR IND1CIS

22. FINGER PADS: THUMB. INDEX. PALMAR SURFACE

1 I ENDON OF EXTENSOR CARPI ULNARIS

2 TENDONS OF EXTENSOR DIGITORUM COM Si UN IS

3 HEAD OF ULNA

4 ANNULAR LIGAMENT

5 ORIGIN OF EXTENSOR CARPI ULNARIS

6 ABDUCTOR DIGITI MINIMI QUINT!

7 TENDON OF EXTENSOR DIGIT! MINIMI

& TENDONS OF EXTENSOR DIGITORUM COMMUNIS 9 TENDINOUS INTERJUNCTURES

LEFT HAND, DORSAL VIEW

LEFT HAND, DORSAL VIEW

t ABDUCTOR POLLICIS LONG US

2 EXTENSOR POLLICIS BREVIS

3 FLEXOR CARPi RADIALIS

4 BRACH IORADIALIS

5 ANNULAR LIGAMENT

6 TRAPEZIUM BONE: OF WRIST

7 TENDON OF EXTENSOR POLLICJS LONG US K TENDON OF EXTENSOR POLLICIS BREVIS 7 BASE OF METACARPAL 1

10 ABDUCTOR POLUCIS BREVIS (THENAR EMINENCE) IL INTEROSSEUS MUSCLES. L II 12. ADDUCTOR POLUCIS

13 LUMBRICAL 1

14 FINGER PADS. PALMAR SURFACE 13 EXTENSOR DIGtTORUM COMMUNIS 16 EXTENSOR POLLICIS LONG US

17. HAMATE BONE OF WRIST

18 TENDONS OF EXTENSOR DIGtTORUM COMMUNIS 19. TENDON OF EXTENSOR CARPI RADIALIS BREVIS

20 TENDON OF EXTENSOR CARPI RADIALIS LONGUS

21 TRAPEZOID BONE OF WRIST 22. TENDON OF EXTENSOR INDICIS 23 FINGERS:

FIRST. POLLEX (THUMB)

SECOND. INDEX

THIRD. MED I US (MIDDLE)

FOURTH. DIGITUS ANNULARIS (RING)

RIGHT HAND, PALMAR ASPECT

TENDON OF FLEXOR CARPI RADIALIS FLEXOR DIG HORUM SUBLIMIS TENDON OF PALM AR IS LONGUS EMINENCE OF RADIAL BONE OPPONENS P01XICIS ADDUCTOR POLLICIS BREVlS F1XXOR POLLICIS BREVlS ADDUCTOR POLLICIS TRANSVERSUS DORSAL INTEROSSEUS I TENDON OF FLEXOR POLLICIS LONGUS ( INGER PADS

SHEATH FOR FLEXOR TENDONS FINGERS:

FIRST. POLLEX (THUMB)

SECOND, INDEX

THIRD. MEDIUS (MIDDLE)

FOURTH. DIGITUS ANNULARIS (RING)

FIFTH. DIGITUS MINIMUS (LITTLE)

TENDON OF PAL MARIS LONGUS

FLEXOR DIGITORLM SUBLIMIS

FLEXOR CARPI ULNAR IS

ANNULAR LIGAMENT

PISIFORM BONE OF WRISI

HOOK OF HAMATE BONE OF WRIST

ABDUCTOR DIGITI MINIMI QUINTI

FLEXOR DIG! It MINIMI

TENDONS Ol FLEXOR DIG HORUM SUBLIMIS

PALMAR INTEROSSE1

FIBROUS SHEATH

FINGER PADS

LEFT HAM), DORSAL ASPECTt SIDE VIEW

EXTENSOR DIGITORUM COMMUNIS ANNULAR LIGAMENT EMINENCE OF LUNATE BONE OF WRIST TRIQUETRUM BONE OF WRIST HAMATE BONE OF WRIST

ORIGIN OF TENDON OF EXTENSOR CARPI ULNAR IS

BASE OF METACARPAL V

DORSAL INTEROSSEUS

TENDINOUS INTERJUNCTURE

TENDONS or EXTENSOR DIGITORUM COMMUNIS

FINGER PADS

FINGERS:

FIRST. POLLEX (THUMB)

SECOND. INDEX

THIRD, MED1US (MIDDLE)

FOURTH, DIGITUS ANNULARIS <RING>

FIFTH. DIGITUS MINIMUS (LITTLE)

EXTENSOR CARPI ULNARIS

FLEXOR CARPI ULNARIS

HEAD OF ULNA

FLEXOR DIGITORUM SUBUMIS PAL.MARIS LONGUS PISIFORM BONE OF WRIST THENAR EMINENCE OPPONENS POLUC1S ABDUCTOR POLLICIS FLEXOR POLLICIS B RE VIS HYPOTHENAR EMINENCE ABDUCTOR DIGITI MINIMI QUINTI FINGER PADS OF THUMB I NTH R Pi I ALANG EAL WE B B1NG

VEINS OF THK HAND

Blood vessels through the body tend to lie in depressions, general!} in hollows between elevated forms. They are thus in a position of safety, out of the way of impact or injury*. This is particularly true of the hand, where no veins protrude on ihe palmar side and where they tend to tie between forms on the dorvjl side. The drawing at left shows the venous net* work coursing around the elevated knuckles, circling and crossing the finger shanks, and rising along the side plane* of (he fingers- Higher up, (he venous system branches off into two main trunks (A I. A2j and two main tributaries iBJ> B2i ascending vertically from a transverse channel, the dorsal venous arch (C) above the palm knuckles.

The draw mg at right, with arm extended downward, shows the location of veins along (he main muscles of the inner arm. Note their deep entrenchment, especiall\ at (he elbow .

DORSAL VENOUS SYSTEM

Here ami on the opposite page, the principle of nonvulnerabiliiy bccomcs readily apparent. The network of blood vessels and tributaries on the donal side of the hand is complex and diversified, since this side of the hand is not subjected to the unremitting activity of the palmar side.

L BASILIC VEIN, VEERING OUTWARD

2. CEPHALIC VEIN. VEERING INWARD

3, TRIBUTARIES. MAJOR

4, TRIBUTARIES, MINOR

5. DORSAL VENOUS ARCH 6 DORSAL DIGITAL VEINS

PALMAR VENOUS SYSTEM

Conversely, the palmar venous system is markedly simpler than that of the dorsal side, especially in the fingers. This system allows for the Hexing, closing, and clenching actions of the inner hand, with the ex* tremcs of pressure encountered through a working day.

I, CEPHALIC VEIN

2 MEDIAN VEIN

3 TRIBUTARIES TO BASILIC VEIN

4. TRANSVERSE PALMAR ARCH

5. LONGITUDINAL DIGITAL VEINS

I, CEPHALIC VEIN

2 MEDIAN VEIN

3 TRIBUTARIES TO BASILIC VEIN

4. TRANSVERSE PALMAR ARCH

5. LONGITUDINAL DIGITAL VEINS

Continue reading here: Anatomical Landmarks And Surface Stress

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Drawing Bones On Your Hand

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