UE Part 3 Flashcards
- What are keratinized plates on the dorsum of the tips of the fingers that consist of the proximal hidden part or root, the exposed part or body, and the distal freeborder?
- What are its parts?
- Fingernails
2. Nail bed; Nail fold; Eponychium; Hyponychium; Lunula (NNEHL)
Borders and floor of Anatomic Snuffbox
medially: tendon of the extensor pollicis longus muscle (EPL)
laterally: tendons of the extensor pollicis brevis and abductor pollicis longus muscles (EPB; APL)
Floor: scaphoid and trapezium bones
• Is a triangular interval limited proximally by the styloid process of the radius and crossed by the radial artery.
Anatomic Snuffbox
- Is the expansion of the extensor tendon over the metacarpophalangeal joint and is referred to by clinicians as the extensor hood.
- Provides the insertion of the lumbrical and interosseous muscles and the extensor indicis and extensor digiti minimi muscles.
Extensor Expansion
Where does the flexor digitorum superficialis insert and where does flexor digitorum profundus insert?
FDS: base of the middle phalanx
FDP: base of the distal phalanx
(hammer or baseball finger) is a finger with permanent flexion of the distal phalanx due to an avulsion of the lateral bands of the extensor tendon to the distal phalanx. Boutonniere deformity is a finger with abnormal flexion of the middle phalanx and hyperextension of the distal phalanx due to an avulsion of the central band of the extensor tendon to the middle phalanx or rheumatoid arthritis.
Mallet finger
It results from stenosing (narrowing) tenosynovitis or occurs when the flexor tendon develops a nodule or swelling that interferes with its gliding through the pulley, causing an audible clicking or snapping. Symptoms are pain at the joints and a clicking when extending or flexing the joints. This condition may be caused by rheumatoid arthritis, repetitive trauma, and wear and tear of aging of the tendon. It can be treated by immobilization by a splint, an injection of corticosteroid into the flexor tendon sheath to shrink the nodule, or surgical incision of the thickened area.
Cannot actively extend finger ; passively extend finger
Trigger finger
An inflammation of the tendon and synovial sheath, and puncture injuries cause infection of the synovial sheaths of the digits. The tendons of the second, third, and fourth digits have separate synovial sheaths so that the infection is con fined to the infected digit, but rupture of the proximal ends of these sheaths allows the infection to spread to the midpalmar space. The synovial sheath of the little finger is usually continuous with the common synovial sheath (ulnar bursa), and thus, infection may spread to the common sheath and thus through the palm and carpal tunnel to the forearm. Likewise, infection in the thumb may spread through the synovial sheath of the flexor pollicis longus (radial bursa).
Tenosynovitis
What are the synovial flexor sheaths?
- Common Synovial Flexor Sheath (Ulnar Bursa)
2. Synovial Sheath for Flexor Pollicis Longus (Radial Bursa)
What are the fascial spaces of the palm?
- Thenar Space
2. Midpalmar Space
Caused by compression of the median nerve due to the reduced size of the osseofibrous carpal tunnel, resulting from inflammation of the flexor retinaculum, arthritic changes in the carpal bones, or inflammation or thickening of the synovial sheaths of the flexor tendons. It leads to pain and paresthesia (tingling, burning, and numb ness) in the hand in the area supplied by the median nerve and may also cause atrophy of the thenar muscles in cases of severe compression. However, no paresthesia occurs over the thenar eminence of skin because this area is supplied by the palmar cutaneous branch of the median nerve.
Carpal tunnel syndrome
What are the structures transmitted by Carpal Tunnel?
(1) median nerve and the
tendons of (2) flexor pollicis longus (FPL),
(4) flexor digitorum profundus (FDP), and
(4) flexor digitorum superficialis (FDS) muscles. (10 structures)
• Is formed anteriorly by the flexor retinaculum and posteriorly by the carpal bones.
Carpal Tunnel
- Serves as an origin for muscles of the thenar eminence.
- Forms the carpal (osteofascial) tunnel on the anterior aspect of the wrist. Is attached medially to the triquetrum, the pisiform, and the hook of the hamate and laterally to the tubercles of the scaphoid and trapezium.
- Is crossed superficially by the ulnar nerve, ulnar artery, palmaris longus tendon, and palmar cutaneous branch of the median nerve.
Flexor Retinaculum
An ischemic muscular contracture (flexion deformity) of the fingers and sometimes of the wrist, resulting from ischemic necrosis of the forearm flexor muscles, caused by a pressure injury, such as compartment syndrome, or a tight cast. The muscles are replaced by fibrous tissue, which contracts, producing the flexion deformity.
Volkmann contracture
