77 465 Anatomy of the Hand The tendon of FDS inserts on the volar aspect of the middle phalanx, and the FDP tendon inserts on the volar aspect of the distal phalanx. FDS flexes the PIP joint and FDP flexes primarily the DIP joint. In the digits, the flexor tendons travel in synovial-lined tunnels called flexor tendon sheaths. The sheaths are anchored to the bones by a series of five annular pulleys, numbered A1-A5 from proximal to distal. The odd numbered pulleys are located over the joints; the even pulleys lie over the bones. There are three thin cruciate pulleys, numbered C1-C3, that main- tain tendon motion and collapse during flexion. The palmer aponeurosis lies proxi- mal to the A1 pulley and is often referred to as the A0 pulley. It acts in unison with the first two annular pulleys. Proximal to the entrance into the digital sheath (A1 pulley), the FDS tendon lies palmer to the FDP tendon. At this point, the FDS tendon divides and becomes deep to the FDP tendon. The two portions reunite at Camper’s chiasma and go on to attach to the middle phalanx. The FDP tendon, after passing through the FDS bifurcation, attaches to the distal phalanx. Flexor pollicis longus (FPL) is the primary flexor of the thumb. It is the most radial structure in the carpal tunnel. It travels in its own fibrous sheath in the palm and inserts into the base of the distal phalanx of the thumb. The thumb, unlike the fingers, has two annular pulleys, A1 and A2, located over the MP and IP joints, respectively. Lying between them is an oblique pulley that is the most important of these three pulleys. Fingertip The fingertip is the end organ for touch, enabling the hand to relay the shape, tem- perature, and texture of an object. The skin covering the pulp of the finger is very durable and has a thick epidermis with deep papillary ridges. The glabrous skin of the fingertip is well-suited for pinch and grasp functions. Its volar surface consists of a fatty pulp covered by highly innervated skin. The skin of the fingertip is firmly anchored to the underlying terminal phalanx by multiple fibrous septa that traverse the fatty pulp. Hence an infec- tion that develops within the pulp can result in a closed space infection, or felon. Dorsal Anatomy Wrist The extrinsic muscles that extend the hand and fingers enter the wrist through six synovial-lined, dorsal compartments covered by the extensor retinaculum. At the wrist, the tendons are surrounded by a sheath, but this sheath is not present in the hand and fingers. The six compartments are numbered 1-6 from radial to ulnar: 1. Abductor pollicis longus (APL), extensor pollicis brevis (EPB) 2. Extensor carpi radialis brevis (ECRB), extensor carpi radialis longus (ECRL) 3. Extensor pollicis longus (EPL) 4. Extensor digitorum communis (EDC), extensor indices proprius (EIP) 5. Extensor digiti minimi (EDM) 6. Extensor carpi ulnaris (ECU) The first compartment is commonly involved in stenosing tenosynovitis, termed de Quervain’s disease. The second compartment contains the radial extensors of the wrist, and this compartment is located beneath the anatomic snuffbox. The hollow of the snuffbox (so named because it was a common site for the placement of snuff) is easily created by extending and abducting the thumb. The radial artery passes through the snuffbox, and the scaphoid bone is deep to it. Therefore, tenderness in the snuffbox can be seen in scaphoid fractures. The second and third compartments are separated by Lister’s tubercle. 77 466 Practical Plastic Surgery Hand and Fingers The four fingers are extended by EDC; however the communis tendon to the little finger is present only 50% of the time. The index and little fingers also have independent extensor muscles—EIP and EDM, respectively. These tendons usually lie ulnar and deep to the communis tendons to these two fingers. The EDC tendons are joined proximally to the MP joints by the juncturae tendinum. They are almost always present between the EDC of the middle, ring and little fingers. Thus, lacerations proximal to the juncturae may not impair digit extension due to the connection to the adjacent digits. The tendons inserts proxi- mally into the MP joint volar plate through attachments known as the sagittal bands. Distal to the MP joint, the extensor tendons divide into one central and two lateral slips. The central slip inserts into the middle phalanx and extends the PIP joint. The lateral slips reunite distally and attach to the distal phalanx, extending the DIP joint. The thumb is extended by three tendons: the first metacarpal by APL, the proxi- mal phalanx by EPB, and the distal phalanx by EPL. However, the MP and IP joints of the thumb can both be extended by EPL due to the attachments of the dorsal apparatus. It is worth mentioning that the IP joint of the thumb is extended by the combined actions of all three major nerves: the radial nerve (EPL), the median nerve (thenar muscles) and the ulnar nerve (adductor pollicis). Deep to the extensor tendons and proximal to the metacarpals lies the dorsal carpal arch. This is the dorsal anastomosis between the radial and ulnar circulation. The dorsal metacarpal arteries originate from this arch. Fingertip The fingernail protects the fingertip and has a major role in tactile sensation and fine motor skills. The nail complex, or perionychium, includes the nail plate, the nail bed, and the surrounding skin on the dorsum of the fingertip (paronychium). The fingernail is a plate of flattened cells layered together and adherent to one another. The nail bed lies immediately deep to the fingernail. The nail bed is composed of the germinal matrix, the sterile matrix, and the roof of the nail fold. The germinal matrix, which produces over 90% of nail volume, extends from the proximal nail fold to the distal end of the lunula. The lunula represents the transition zone of the proximal germinal matrix and distal sterile matrix of the nail bed. The sterile matrix (ventral nail) contributes additional substance largely responsible for nail adherence. The roof of the nail fold (dorsal nail), which includes the germinal matrix, is responsible for the smooth, shiny surface of the nail plate. The hyponychium is the area immediately below the fingernail at its cut edge which serves as a barrier to subungual infection, and also marks the terminal extension of bone support for the nail bed. The epony- chium is the skin covering the dorsal roof of the nail fold. The paronychium is the skin at the nail margin, folded over its medial and lateral edges. Innervation of the Hand and Fingers The median, ulnar and radial nerves are the primary nerves of the hand and fingers. The first two have both motor and sensory fibers, whereas the radial nerve provides only sensory fibers to the hand. Its motor branches terminate in the arm and forearm. Median Nerve The median nerve travels in the forearm between the muscle bellies of FDP and FDS and provides motor input to most of the flexors of the forearm. Just proximal to the wrist, it gives off the palmar cutaneous branch which supplies sensation to the 77 467 Anatomy of the Hand thenar region. At the wrist it enters the carpal tunnel, where it is the most superficial of the structures that traverse this tunnel as described above. It then gives off the motor branch which innervates the radial side of the thenar muscles: opponens pollicis, abductor pollicis brevis, the superficial part of flexor pollicis brevis, as well as the two radial lumbricals. Finally, it divides into sensory branches whose territory includes the palmar surface of the thumb, index, middle, and radial side of the ring fingers, and the radial side of the palm (palmar sensory branch). On the dorsal surface, it sends sensory branches to the distal third of the above-mentioned fingers. The most consistent sign of median nerve injury is loss of skin sensibility on the palmer surface of the first three digits and loss of thenar opponens function. Ulnar Nerve The ulnar nerve travels in the forearm ulnar to the FDP muscle belly. It gives off its palmar sensory branch proximal to the wrist. At the wrist it travels in Guyon’s canal, after which it begins to branch into many motor and sensory branches. It innervates all the intrinsic hand muscles except those mentioned above that are innervated by the median nerve. The last muscle innervated by the ulnar nerve is the first dorsal interosseus nerve. Its sensory territory includes both the palmar and dorsal sides of the little finger and the ulnar side of the ring finger. A common sensory sign of ulnar nerve injury is the loss of sensibility to the small and ulnar side of the ring fingers. Motor signs include FCU paralysis, interosseous and thumb adduction loss with a weak “key pinch,” and FDP paralysis of the small and ring fingers. A long-standing injury can present with the classic “claw hand” deformity. Radial Nerve The radial nerve provides all the motor innervation of the extensor muscles of the forearm. Only the superficial branch of the radial nerve reaches the hand. This purely sensory nerve travels over the radial side of the wrist. It then branches into the dorsal digital nerves that supply the skin on the dorsum of the thumb, index, middle, and radial side the ring fingers (with the exception of the distal third of each which is supplied by the median nerve). Signs of injury include loss of sensibility on the dorsum of the hand and in the first web space. Patients will be unable to extend their fingers. Pearls and Pitfalls A resource that is highly recommended for understanding hand anatomy and anatomic relationships is The Interactive Hand CD-ROM (McGrouther DA, Colditz JC, Harris JM, Eds.) published by Primal Pictures, Inc. 2002. The upper extremity can be rotated and displayed from various angles, and it can be viewed layer by layer from bone to skin. Suggested Reading 1. Bogumill GP. Functional anatomy of the flexor tendon system of the hand. Hand Surg 2002; 7(1):33-46. 2. Furnas DW. Anatomy of the digital flexors: Key to the flexor compartment of the wrist. Plast Reconstr Surg 1965; 36(3):315-9. 3. In: Green DP, Hotchkiss RN, Pederson WC, Wolfe SW, eds. Green’s Operative Hand Surgery. 5th ed. New York: Churchill Livingstone, 2005. 4. Lister’s The Hand. In: Smith P, ed. Diagnosis and Indications. 4th ed. New York: Churchill Livingstone, 2002. 5. Rockwell WB, Butler PN, Byrne BA. Extensor tendon: Anatomy, injury, and recon- struction. Plast Reconstr Surg 2000; 106(7):1592-603. Chapter 78 Practical Plastic Surgery, edited by Zol B. Kryger and Mark Sisco. ©2007 Landes Bioscience. Radiographic Findings Zol B. Kryger and Avanti Ambekar Introduction Radiologic diagnosis of bony hand injury and deformity is often successfully achieved with conventional radiographs, despite advances in cross-sectional imag- ing. At least two orthogonal views should be performed routinely. Special views, such as the scaphoid view, can be helpful in selected cases. The images shown in this chapter were obtained and reprinted with permission from the website http:// www.gentili.net. Figure 78.1. P-A view of a normal hand radio- graph. 78 469 Radiographic Findings A Systematic Approach An organized evaluation is required for all image interpretation. The patient’s name, date of exam, correct body part, and laterality (right or left side) should be verified prior to analyzing the image. The exam should be assessed for quality and completeness. Attention can then be turned to film interpretation. The bones, joint spaces, and soft tissues should be sequentially inspected. Each feature should be evaluated in a systematic fashion (e.g., from proximal to distal). All abnormalities should be confirmed on a second view. Figure 78.2. Oblique view of a normal hand radiograph. 78 470 Practical Plastic Surgery Figure 78.3. Osteoarthritis of the hand, with joint space narrowing and adjacent bony sclerosis. The DIP joints and 1st CMC joint (thumb) are characteristically in- volved. Figure 78.4. Osteoarthritis of the fingers. Note greater involvement of the DIP joints compared to the IP joints. Figure 78.5. Fracture of the scaphoid bone. The scaphoid is the most commonly fractured car- pal bone, accounting for 80% of all carpal fractures. It is often the result of a fall on an outstretched hand. Scaphoid fractures are at high risk for nonunion and avas- cular necrosis. 78 471 Radiographic Findings Figure 78.6. Fracture of the ra- dial styloid, also termed a chauffeur’s fracture. A scapho- lunate ligament tear often ac- companies this fracture. Figure 78.7. Fracture of the first metacarpal base, If it is intra-articular, it is referred to as a Bennett fracture. If it also demonstrates comminution, it is called a Rolando fracture. 78 472 Practical Plastic Surgery Figure 78.8. Fifth metacarpal fracture, commonly known as a boxer’s fracture. Figure 78.9. Fracture of the hamate bone. Hook fractures commonly occur in golfers, baseball players or construc- tion workers with a complaint of a dull ache when gripping. Figure 78.10. Fracture of the distal phalanx, or a mallet fracture. Distal phalanx fractures can occur due to avul- sion of a bony fragment attached to the flexor or exten- sor tendon. 78 473 Radiographic Findings A B Figure 78.11. Dislocation of the lunate bone in the P-A (A) and lateral views (B). Note the normal position of the capitate bone with respect to the distal radius. In milder cases, the lunate can sublux dorsally after scapholunate ligament disruption (DISI) and will rarely sublux volarly after lunotriquetral ligament disruption (VISI). Figure 78.12. Triquetrum fracture. Usu- ally associated with other wrist fractures after a fall on an outstretched arm. This fracture is usually a dorsal cortex chip fracture best seen on a lateral view. 78 474 Practical Plastic Surgery Figure 78.13. Avulsion frac- ture of the ulnar collateral ligament insertion at the base of the thumb, com- monly referred to as a gamekeeper’s or skier’s thumb. If the fragment is widely displaced, a Stener lesion can result, requiring surgical intervention. Figure 78.14. Rheumatoid arthritis of the wrist, demon- strating bony ankylosis of the carpus, ulnar deviation at the MP joints, and ulnar styloid erosions. Figure 78.15. Late rheuma- toid arthritis. There is marked MP joint destruction and nar- rowing. Weakening of the radial sagittal bands causes ulnar subluxation of the ex- tensor mechanism and sub- sequent ulnar deviation of the MP joints. [...]... dorsal compartment sparing a dorsal incision Suggested Reading 1 Botte MJ, Gelberman RH Acute compartment syndrome of the forearm Hand Clin 19 98; 14:391 2 Gellman H, Buch K Acute compartment syndrome of the arm Hand Clin 19 98; 14: 385 3 Ortiz Jr JA, Berger RA Compartment syndrome of the hand and wrist Hand Clin 19 98; 14:405 4 Serokhan AJ, Eaton RG Volkmann’s ischemia J Hand Surg [Am] 1 983 ; 8: 806 5 Whitesides... 1 984 ; 2(2):29 5-3 12 2 Daniels IInd JM, Zook EG, Lynch JM Hand and wrist injuries: Part I Nonemergent evaluation Am Fam Physician 2004; 69 (8) :194 1 -8 3 Daniels IInd JM, Zook EG, Lynch JM Hand and wrist injuries: Part II Emergent evaluation Am Fam Physician 2004; 69 (8) :194 9-5 6 4 Kuschner SH, Ebramzadeh E, Johnson D et al Tinel’s sign and Phalen’s test in carpal tunnel syndrome Orthopedics 1992; 15:129 7-1 302... HIV, and other immune disorders) Treatment The principles of treatment are similar in all hand infections They are summarized in Table 80 .2 Practical Plastic Surgery, edited by Zol B Kryger and Mark Sisco ©2007 Landes Bioscience 482 Practical Plastic Surgery Table 80 .1 Hand infections and the empiric antibiotics of choice Infection Human bite Tenosynovitis Common Bacterial Pathogen S aureus, streptococci,... adult hand Acta Chir Plast 1996; 38( 2):6 7-7 1 6 Waylett-Rendall J Sensibility evaluation and rehabilitation Orthop Clin North Am 1 988 ; 19(1):4 3-5 6 Chapter 80 Soft Tissue Infections Zol B Kryger and Hongshik Han Introduction Infections of the hand can range from minor, superficial cases to infections of the deeper spaces of the hand that can potentially become limb-threatening and must be treated aggressively... making compartment syndrome even more unlikely to occur Forearm The forearm structures are contained within three compartments: an anterior flexor (volar) compartment, a posterior extensor (dorsal) compartment, and the mobile wad (superficial radial-dorsal side) These compartments do not communicate freely with one another nor with the hand distally and the arm proximally Therefore, forearm compartment... to Practical Plastic Surgery, edited by Zol B Kryger and Mark Sisco ©2007 Landes Bioscience Compartment Syndrome of the Upper Extremity 487 impaired venous return, increased capillary permeability and vasodilation, all of which cause greater fluid accumulation and serve to increase the pressure even further The tissues most sensitive to the resulting ischemia are nerve and muscle Greater than 6 -8 hours... nerves/muscles • Intact pulses or dopplerable arterial signals Compartment Pressure Measurements As stated above, compartment syndrome is a clinical diagnosis and pressure measurements only aid in confirming the diagnosis In the uncooperative or obtunded patient however, an accurate exam is not possible, and objective pressure 488 Practical Plastic Surgery determination can be of value if there is a high index... well-hydrated A urine output of at least 1-2 ml/kg/ hr should be maintained Serum creatinine phosphokinase (CPK) levels should also be followed since extremely high CPK levels are also a risk factor for renal failure 490 Practical Plastic Surgery 81 Figure 81 .2 Fasciotomy incisions over the second and fourth metacarpals for releasing the dorsal and palmar interosseus compartments Longitudinal fasciotomy incisions... arm contains two compartments: the anterior flexor compartment (biceps and brachialis) and the posterior extensor compartment (triceps) The fascia encasing and separating these two compartments is relatively weak, and consequently fluid accumulation in one compartment will usually make its way into the other compartment and the surrounding subcutaneous tissues Furthermore, the compartments of the arm... the distal ulna is within ± 1-2 mm of the distal radius (Fig 83 .1) • Inclination: the radius tilts toward the ulna at an angle of 22˚ when measured from a line perpendicular to its long axis on AP view (Fig 83 .1) • Volar tilt: on lateral view, the radius tilts in a volar direction 11˚ when measured from a line perpendicular to its long axis (Fig 83 .2) Practical Plastic Surgery, edited by Zol B Kryger . recipi- ents, HIV, and other immune disorders). Treatment The principles of treatment are similar in all hand infections. They are summa- rized in Table 80 .2. 80 482 Practical Plastic Surgery The. best seen on a lateral view. 78 474 Practical Plastic Surgery Figure 78. 13. Avulsion frac- ture of the ulnar collateral ligament insertion at the base of the thumb, com- monly referred to as a gamekeeper’s. Waylett-Rendall J. Sensibility evaluation and rehabilitation. Orthop Clin North Am 1 988 ; 19(1):4 3-5 6. Chapter 80 Practical Plastic Surgery, edited by Zol B. Kryger and Mark Sisco. ©2007 Landes Bioscience. Soft