Human Anatomy Vol 1

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UPPEB LIMB

Dissection t

1. A horizontal incision at the distal crease of front of
   the wrist has already been made.


2. Make a veftical incision from the centre of the above
   incision through the palm to the centre of the middle
   finger (Fig.9.14).


3. Make one horizontal incision along the distal palmar
   crease.


4. Make an oblique incision starting 3 cm distalto incision

no. (^2) and extend it till the tip of the distal phalanx of
the thumb.
Thus the skin of the palm gets divided into
3 areas. Reflect the skin of lateral and medial flaps on
their respective sides. The skin of the intermediate flap
is reflected distally towards the distal palmar crease.
Further the skin of middle finger is to be reflected on
either side.
Superficial fascia and deep fascia
Remove the superficial fascia to clean the underlying
deep fascia.
Deep fascia is modified to form the flexor retinaculum
at wrist, palmar aponeurosis in the palm, and fibrous
flexor sheaths in the digits. ldentify the structures on its
superficial surface. Divide the flexor retinaculum between
the'thenar and hypothenar eminences, carefully
preserving the underlying median nerve and long flexor
tendons.
ldentify long flexor tendons enveloped in their
synovial sheaths including the digital synovial sheaths.
Fig. 9.14: lncisions of palm and digits (1-4)
Feotules
The human hand is designed:
i. For grasping,
ii. For precise movements,
iii. For serving as a tactile organ.
There is a big nrea in the motor cortex of brain for muscles
of hand.
The skin of the palm is:
i. Thick for protection of underlying tissues.
ii. Immobile because of its firm attachment to the
underlying palmar aponeurosis.
iii. Creased. All of these characters increase the
efficiency of the grip.
The skin is supplied by spinal nerves C6, C7, C8
(see Fig.7.1) through the median and ulnar nerve.
The superficial fascia of the palm is made up of
dense fibrous bands which bind the skin to the deep
fascia (palmar aponeurosis) and divide the
subcutaneous fat into small tight compartments which
serve as water-cushions during firm gripping. The
fascia contains a subcutaneous muscle, the palmaris
breois, which helps in improving the grip by steadying
the skin on the ul:rar side of the hand. The superficial
metacarpal ligament which stretches across the roots
of the fingers over the digital vessels and nerves, is a
part of this fascia.
The deep fascia is specialised to form:
i. The flexor retinaculum at the wrist.
ii. The palmar aponeurosis in the palm.
iii. The fibrous flexor sheaths in the fingers. All three
form a continuous structure which holds the
tendons in position and thus increase the
efficiency of the grip.
FIexol Relinoculum
Flexor (Latin to hold back) reinaculum is a strong fibrous
band which bridges the anterior concavity of the carpus
and converts it into a tunnel, the carpal tunnel (Fig. 9.15).
A eftn'perufs
Medially, to
1 The pisiform bone.
(^2) To the hook of the hamate.
Laterally, to
L The tubercle of the scaphoid, and
(^2) The crest of the trapezium.
On either side, the retinaculum has a slip:
L The lateral deep slip is attached to the medial lip of the
groove on the trapezium which is thus converted into
a tunnel for the tendon of the flexor carpi radialis;
2 The medial superficial slip (aolar carpal ligament) is
attached to the pisiform bone. The ulnar vessels and
nerves pass deep to this slip (Figs 9.1,5 and9.1.6).