586 THE NERVOUS SYSTEM. 
half of the flexor profundus digitorum, and the pronator quadratus, minute 
medullary branches to the radius and ulna, and twigs to the periosteum and 
interosseous membrane. 
(+) Palmar Cutaneous Branch.—In the lower third of the forearm a sinall 
cutaneous branch arises, which pierces the deep fascia and crosses the anterior 
annular ligament to reach the palm of the hand. It supphes the skin of the palm 
and communicates with a similar branch of the ulnar nerve. This branch is not 
always present. BSL 
Branches in the Hand.—In the hand the median nerve gives off its terminal 
branches. These are 
| | muscular and cutaneous. 
The main muscular 
ee branch arises just below 
the anterior annular 
ligament and passes out- 
wards to the base of the 
thenar eminence ; enter- 
ing the ball of the thumb 
superficially on the inner 
side, it supplies branches 
to the abductor pollicis, 
opponens pollicis, and 
the superficial head of 
the flexor brevis pollicis. 
The cutaneous 
branches are five in 
number. Three separ- 
ate branches supply 
each side of the thumb 
and the radial side of 
the index finger. The 
two remaining branches 
subdivide at the cleft 
between the second 
and third, and the third 
and fourth fingers re- 
spectively, into branches 
which supply the ad- 
jacent sides of the 
second and third, and 
the third and fourth 
fingers. From the 
nerves which supply re- 
spectively the radial side 
of the index finger, and 
the contiguous sides of 
(A) represents the distribution of the several nerves, the letters indicating the index and third 
their nomenclature. Acr, Acromial branch (cervical plexus) ; Circ, fingers, fine muscular 
Cutaneous branch of circumflex nerve; M.SE, Superior external branches arise for the 
cutaneous branch of musculo-spiral nerve ; M.C, Musculo-cutaneous two outer lumbrical 
nerve ; M, Median nerve: U, Ulnar nerve ; I.C, Internal cutaneous fs 
nerve; L.I.C, Lesser internal cutaneous nerve (Wrisberg) ; I.H, Inter- muscles. The cutaneous 
costo-humeral nerve ; T.2, 3, 4, 5, 6, Anterior and lateral branches of branches of the median 
intercostal nerves, nerve are placed in the 
(B) isa schematic representation of the areas supplied by the above nerves, palin between the super- 
the lettering indicating the spinal origin of the branches of distribution 4. l ‘ chy aan 
to each area. V.A.L, Ventral axial line. ficial Ppaimar aren ane 
the flexor tendons. They 
become superficial at the roots of the fingers between the slips of the palmar fascia, 
or, in the case of the nerves to the thumb and radial side of the index finger, at 
the outer edge of the central portion of the palmar fascia. In the fingers they 
- 
Va 
5.6 
c6768 | cat 
Fig. 432.—TuHr Distripution or CuranKous NERVES ON THE FRONT OF 
; THE ARM AND HAnp. 
