Fig. 2.
The Palmar Fasciæ.
1. Palmaris longus tendon; 2. Palmaris brevis; 3. Muscular aponeurosis of hypothenar eminence; 4. Fibres from radiating fascia to hypothenar eminence; 5. Innermost digital portion of central segment of radiating fascia; 6. Fibrous band passing to integumental fold; 7. Transverse fibres appended to radiating fascia; 8. Lateral digital branches of radiating fascia; 9. Portion of vaginal fascia exposed between 5 and 10, Fibres of Gerdy; 11. Superficial digital fascia continuous with fibres of Gerdy; 12. Thenar portion of radiating fascia blending with muscular aponeurosis.
The transverse fibres of Gerdy are really the proximal portion of a superficial fascia which invests the whole of the four inner digits immediately under the skin, forms the subcutaneous web of the fingers, and is continuous posteriorly with the superficial fascia of the back of the hand. As seen in the palm, it consists of loose fibres intermingled with fat, running for the most part in a transverse direction from the second to the fifth metacarpo-phalangeal joint. Proximally it presents a somewhat sharply defined free border placed nearly opposite the joint fissure, and extends distally, as before stated, to the fingers and the inter-digital web, and is connected with the deeper tissues by a few fibres, but is for the most part separated from them by loose, whitish fat. On the fingers the tissue constitutes a sheath investing the tendinous, bony, and ligamentous structures and the lateral bands derived from the radiating fascia. It takes the form of a distinctly membranous sheet dorsally and at the sides, but in front it appears as a coarse irregular network supporting the digital vessels and nerves, and containing a large quantity of fat in its meshes. It is connected strongly with the corium, especially at the palmar folds, and more loosely with the deeper structures by fine fibres.
Fig. 3.
Transverse Section of Hand through the Third, Fourth, and Fifth Metacarpal Bones.
1. Palmar integument; 2. Fat transversed by fibres from 3; 3. Radiating fascia; 4. Vaginal fascia, superficial portion; 5. Palmar vessels and nerve; 6. Flexor tendons and lumbricales; 7. Vaginal sheath blending with fascia of interossei; 8. Septal fibres from vaginal fascia to bone; 9. Interossei; 10. Middle metacarpal bone; 11. Extensor tendon and sheath; 12. Superficial fascia beneath dorsal integument; 13. Fascia of hypothenar eminence; 14. Muscles of little finger.