(1) FCU ¨ pisiform
(2) Ulnar nerve & artery (nerve outside artery)
(3) FDS tendons (and FPL)
(4) Palmaris longus
(5) Median nerve (just radial to palmaris, and under retinaculum)
(6) FCR (in its own tunnel compartment; ¨
(7) Radial artery
(8) Ab PL
= four layers, as in foot:
(1) Palmar aponeurosis
(2) Short muscles of thumb & little finger, long flexor tendons
(3) Adductor muscle of thumb
Metacarpal bones and interosseous muscles
Same 4 layers as foot:
i) strong aponeurosis
ii) short muscles and long flexor tendons
iii) adductor of thumb
iv) metacarpal bones
Skin innervation (441): terminal branches of radial nerve, dorsal branch of ulnar nerve
- these share hand and digits with line down middle of ring finger
- nail beds supplied as per distal fingers of flexor compartment.
Dorsal venous network (437): drain palm so that grip does not impede venous return.
- superficial to extensors, proximal to metacarpal heads ˆ basilic (ulnar) and cephalic (radial)
Extensors of the wrist (439): pass beyond retinaculum. 2 radial ¨ base of 2nd metacarpal; 1 ulnar ¨ 5th metacarpal base
Extensors of fingers fan over dorsum (439) and interconnect near metacarpal heads
- these and the adjacent dense fascia roof in the subfascial space
- see written notes for insertions
Dorsal carpal arch (438): posterior arterial anastomosis formed by radial, ulnar and anterior interosseous.
- lies on the back of the carpus ¨ dorsal metacarpal arteries run distally
- split at web spaces ¨ dorsal digital arteries
Palmaris brevis attached to dermis, runs across base of hypothenar eminence. Only muscle supplied by superficial branch of ulnar nerve. Palmar skin attached to palmar aponeurosis by fibrous bands.
= phylogenetically degenerating tendon of palmaris longus. Runs from flexor retinaculum ¨ fans out to fingers to insert into deep transv ligament of palm and base of proximal phalanges. Contraction of this aponeurosis ¨ DupuytrenÕs contracture.
From scaphoid & trapezium on radial side ¨ pisiform & hamate on ulnar side. Pisiform is only bone to give attachment to both flexor & extensor retinacula.
Thenar & hypothenar muscles arise from the FR.
(1) Palmaris longus tendon
(2) Ulnar nerve, & ulnar artery (through GuyonÕs canal)
(3) Palmar cutaneous branch of the median nerve
(4) Superficial palmar branch of radial artery.
FCR tendon pierces the FR on its radial aspect \ has its own compartment.
Carpal concavity + roof of FR ¨ carpal tunnel, containing long flexors of fingers & thumb.
Superficial flexor tendons lying separate in two rows; middle & ring in front of index & little.
Deep flexors in single row, only index tendon is separated. All 8 tendons share common synovial sheath, reflected from radial aspect. FPL has own sheath. Median nerve passes between FDS and FCR; gives off motor branch to thenar muscles at distal margin of FR.
Median nerve compression at this level ¨ thenar wasting, loss of thumb opposition power, anaesthesia of 3½ digits on radial side of hand. Thenar eminence sensation normal due to supply by palmar cutaneous branch of median nerve (this differentiates from median nerve lesion at higher level; also forearm flexors will be weakened eg FPL \ test flexion of TP of thumb).
Begin from distal flexor crease, run along thenar crease to level of distal border of outstretched thumb.
Divide palmar aponeurosis ¨ then divide flexor retinaculum as far as deep fascia of forearm. Identify but donÕt dissect median nerve. Use bipolar diathermy only.
6-79
Abductor pollicis brevis ¨ base of PP and tendon of EPL
Flexor pollicis brevis (ulnar side of AbPB) ¨ radial sesamoid of thumb ¨ PP
Opponens pollicis (deep to other 2) ¨radial aspect of MC
Innervation: muscular (recurrent) branch of median nerve (T1) but AbPB has most variable innervation of any other muscle.
In relaxed position thumbnail is at R angle to fingernails.
Flexion maintains that orientation of thumbnail.
Opposition brings thumb & fingernails to same plane.
Similar in name to thenar muscles
Abductor digiti minimi most ulnar ¨ base of PP
Flexor digiti minimi ¨ base of PP
Opponens digiti minimi ¨ ulnar border of 5th MC
Innervation: deep branch of ulnar nerve (C8, T1)
Arcade lying superficial to everything in palmar compartment. Formed by ulnar artery but is hockey stick in 2/3; if complete it joins the superficial palmar branch of the radial artery. Gives off digital arteries to fingers except radial aspect of index & thumb; these are supplied by the radial artery.
Arteries run dorsally to nerves.
(1) Medial branch ¨ ulnar aspect of little finger
(2) Lateral branch ¨ adjacent sides of little & ring
(1) Medial branch divides into two ¨ adjacent sides of middle & ring, adjacent sides of index & middle
(2) Lateral branch ¨ radial aspect of index; entire ventral aspect and distal dorsal aspect of thumb.
Arise from each of 4 FDP tendons & pass along radial aspect ¨ extensor expansion on dorsum of PP.
Innervation: 2 ulnar muscles by ulnar nerve, 2 radials by median nerve. May be 1:3 or 3:1; always mirrors innervation of FDP bellies.
In contact with MCÕs & interrosei; not part of thenar eminence. Transv head arises from palmar aspect of 3rd MC ¨ ulnar sesamoid of thumb ¨ base of PP. Oblique head from base of 2nd &3rd MCÕs & adjacent carpal bones. Radial artery enters palm between these 2 heads. Innervation: deep branch of ulnar nerve.
Passes across snuffbox ¨ enters hand between 2 heads of 1st dorsal interosseous muscle. 2 Branches:
Arteria radialis indicis ¨ radial side of index finger
Princeps pollicis ¨ both sides of thumb
Main trunk then passes into palm between heads of adductor pollicis to form deep palmar arch along with deep branch of ulnar artery. Deep arch usually complete cf superficial arch. Gives off 3 palmar metacarpal arteries; free anastomosis exists between superficial, deep palmar arches and dorsal metacarpal arteries from dorsal carpal arch.
After GuyonÕs canal ulnar nerve divides.
Superficial branch ¨ palmaris brevis + digital nerves to ulnar 1½ fingers.
Deep branch passes into palm between FDM & AbDM to lie on hook of hamate ¨ arches within concavity of deep palmar arch. Supplies 3 hypothenar muscles, ulnar 2 lumbricals, all interossei and both heads of adductor pollicis.
Innervation: all by ulnar nerve (T1)
Finger adductors. Small, arise from MC of finger they adduct ¨ attach to PP & extensor expansion. Thumb already has powerful adductor, middle finger (as axis of hand) doesnÕt require one. Index, ring and little finger have PI inserting into side facing middle finger.
Abductors. Thumb & little finger already have their own \ only index, middle & ring have DI. Index & ring fingers have DI inserted into side of finger away from middle finger; middle finger has DI inserting into each side. Each DI arises from both MCÕs adjoining interosseous space.
Fibrous septum from each side of palmar aponeurosis divides palm into 3 spaces. Hypothenar space contains no long flexor tendons \ less important.
Overlaid by long flexor tendons to ulnar 3 fingers; fascia separates the tendons & synovial sheath from the space.
Contains 1st lumbrical, long flexors to index finger.
Both FDS & FDP tendons run in common sheath in each finger.
Superficialis tendon splits around FDP tendon and meets behind it ¨ attaches along sides of whole shaft of MP.
Profunda tendon ¨ base of DP.
Each tendon has 2 vincula (= vascular synovial folds).
Tendon adheres to MCPJ as it crosses it ¨ broadens over dorsum of PP & divides into 3 slips. Lateral slips receive insertion from lumbricals & interossei ¨ broad extensor expansion. Central slip inserts into base of MP. Lateral slips reconverge and fuse to insert into base of DP.
Flexor aspect has 1 tendon only, = FPL.
Extensor aspect EPB ¨ PP, EPL ¨ DP. No extensor hood as for fingers; EPL receives fibres from AbPB and adductor pollicis.
Finger ab/adduction. Simultaneous contraction ¨ flexion of MCPJ. Essential for simultaneous MCPJ flexion & IPJ extension. Principle action is to flex the MCPJ, and thus allow extensor digitorum to extend the DIPJ.
Action obscure. Probably allow MCPJ flexion.
See written notes