13 13/3/2012. Adel Muhanna

Transcription

1 13 13/3/2012 Adel Muhanna

2 بسم هللا الرحمن الرحيم The Hand Extensor retinaculum: Deep fascia of anterior compartment of the wrist is thickened to form flexor retinaculum : a bridge that have 6 structures passing above and 10 structures passing below. Deep fascia at the posterior aspect of the wrist is thickened to form extensor retinaculum. Function of extensor retinaulum: holding long extensor tendons while they are working preventing them from bowing. Extensor retinaculum extends medially from psiform bone and hook of hamate to radius laterally ( P,H to R ). Remember : flexor retinaculum extends medially from pisiform bones and hook of hamate to scaphoid and trapezium bones laterally ( P,H to S,T). 1 P a g e

3 There are structures that pass above and others below extensor retinaculum : Structures passing Above : Four structures pass above (2 nerves & 2 veins): -Medial side: 1-dorsal branch of ulnar nerve 2-basilic vein -Lateral side: 1-superficial branch of radial nerve 2-cephalic vein Remember: -Radial nerve devides into:1- deep branch 2-superficial branch that passes deep to brachioradialis to supply dorsal skin of the hand. -ulnar nerve supplies 1&1/2 muscles in the anterior forearm and gives two branches: dorsal branch then palmar branch, then it passes above flexor retinaculum. Structures passing Below: -All the under lying structures are tendons of extensor muscles except one tendon for abductor policis longus muscle. -these tendons are separated by numerous septa deviding them into 6 compartments (tunnels): 1-ext. carpi ulnaris compartment 2-ext. digiti minimi compartment 3-ext. digitorum, extensor indicis compartment 4-ext. carpi radialis longus, ext. carpi radialis brevis compartment 5-ext. policis longus compartment 6-abd. Policis longus, ext.policis brevis compartment -each tunnel is lined by synovial sheath that enclose long extensor tendons. 2 P a g e

4 Hand: It is devided into palmar and dorsal aspects. Skin of the palm is thick and shows many flexure creases that are important clinically and located over joints: 1-proximal palmar crease 2-distal palmar crease Under the thick skin of palm there is superficial fascia that contains fat and also there is septa from skin and that makes performing a surgery at the palmar aspict of the hand difficult. Characteristics of the palm: 1-contains numerous sweat glands. 2-it is hair less. (: ارتفاعة) 3-it has two eminences 3 P a g e

5 -thenar eminence (lateral):located below small muscles of the thumb and contains 3 small muscles (control thumb motion) supplied by median nerve. -hypothenar eminence (medial): located below small muscles of the little finger and contains 3 small muscles(control little finger motion ) supplied by ulnar nerve. Palmar aponeurosis : Deep fascia,which is under superficial fascia, is covering the palm. It is thin at the peripheral part and thick at the central part to form a triangular shaped aponeurosis called palmar aponeurosis. Palmar aponeurosis has an apex(proximal) and a base(distal). - Apex is originated from flexor retinaculum and Palmaris longus tendon. - The base ends at the metacarpophalangeal joint. It gives 4 bands called longitudinal bands that go to the medial 4 fingers and fuse with the fibrous flexor sheath on fingers over long flexor tendons (fibrous flexor sheath is the continuation of longitudinal band). 4 P a g e

6 -Flexor digitorum superficialis and profundus tendons reach the hand by passing under flexor retinaculum. -palmar aponeurosis passes above flexor retinaculum and continues to 4 medial fingers in order to attach tendons of these two muscles (FDS &FDP) with the fibrous sheath. Tendons of (FDS &FDP) are held in their places so they will not bow while they are in action by: 1-flexor retinaculum at the wrist. 2-palmar aponeurosis at the palm 3-fibrous flexor sheath over the fingers At the base, each band divides into 2 parts: 1-superficial part to the skin 2-deep part to fuse to the fibrous flexor sheath at the bases of the proximal phalanx of medial 4 fingers. Palamr aponeurosis partitions structures that are lateral, medial and deep to it by sending 2 septums to MC bones: 1-medial septum descending to the 5 th MC bone from the medial border. 2-oblique septum descending to the 3 rd MC bone from the lateral border, it gives the lateral compartment with the help of deep fascia of the palm. These septums divide the palm into 3 compartments: 1-hypothenar compartment (medial): containing 3 musles for the little finger 2-thenar compartment (lateral): containing 3 musles for the thumb 5 P a g e

7 3-midpalmar compartment (central):containing 1-tendons of FDS,FDP and flexor policis longus muscles (9 tendons) 2- four lumbrical muscles. Functions of palamr aponeurosis : 1-protects underlying structures. 2-gives attachment for the skin in order to form a firm grip. 3-improve the grip. 4- partitioning structures lateral,medial and deep to it by septa into compartments. Small muscles of the hand: Arranged in 5 groups: 1-thenars (FAO) 3Ms: -flexor policis brevis -opponens policis -abductor policis brevis 2-hypothenars (FAO) 3Ms: -opponens digiti minimi -flexor digiti minimi -abductor digiti minimi 3-lumbricals 4Ms: for the medial 4 figers, numbered from medial to lateral side. 4-dorsal interossei 4Ms 5-adductor pollicis 1M 6 P a g e

8 All of these muscles are supplied by ulnar nerve except 5 by median nerve (3 thenars & 1,2 lumbricals) Fibrous flexor sheath: It is a blind tube, that is, it is opened proximally and closed distally,it starts at the base of the proximal phalanx and ends at the base of the distal phalanx. It is thin and lax over the joints and thick over phalanges. It contains long flexor tendons of (FDS &FDP) muscles to hold them in their places while they are in action. Tendons of muscles are surrounded by synovial sheath which secretes oil lubricating material so the tendons move soundless frictionless and easily. Common Synovial flexor sheath (ulnar bursa) is located within the palm for the medial 4 fingers: 7 P a g e Clinical application: elderly people suffer from ticking in their joins because of the depletion of synovial fluid and that causes ticking sound and the friction in these joints.

9 -For little finger it continues around its long tendons. -for for ring, middle and index fingers it stops at the middle of the palm then it continues as digital synovial sheath from the base of proximal phalanx to the base of distal phalanx Because of the wide motion of the thumb, it has its own synovial sheath surrounding flexor policis longus which called (radial bursa). Ulnar bursa and radial bursa communicate with each other(continuous to each other),proximal to the flexor retinaculum, in 50% of people. Clinical application: -with the inflammation in synovial fluid (synovitis), the thumb and the little finger can be fully opened in the sergury because the synovial fluid is continuous in both of them. - in ring, middle and index fingers that is not possible and the infection can not move from common to digital synovial sheath and it will stop at the proximal palmar crease and start at the distal palmar crease. عادل مهنا by: Done 8 P a g e