Human Anatomy Vol 1

(mdmrcog) #1
UPPER LIMB

Flexor digitorum
profundus

Flexor digitorum
superficialis

Fibrous flexor sheath
Capsules of
metacarpophalangeal

Joints

Dissection


Clean the thenar and hypothenar muscles. Carefully
preserve the median nerve and superficial and deep
branches of ulnar nerve which supply these muscles.
Abductor polliiis is the lateral muscle; flexor pollicis
brevis is the medial one. Both these form the superficial
lamina. The deeper lamina is constituted by opponens
pollicis (Fig. 9.19).
Cut through the abductor pollicis to expose the
opponens pollicis. These three muscles constitute the
muscles of thenar eminence.
lncise flexor pollicis brevis in its centre and reflect
its two parts. This will revealthe tendon of flexor pollicis
longus and adductor pollicis on a deeper plane. The
three muscles of thenar eminence are supplied by thick
recurrent branch of median nerve.
On the medial side of hand, identify thin palmaris
brevis muscle in the superficial fascia. lt receives a twig
from the superficial branch of ulnar nerve.

Cruciate fibres
of fibrous sheath

Tendon of flexor
digitorum profundus

Transverse fibres
of fibrous sheath

Flexor digitorum
superficialis

Deep transverse
metacarpal ligament

Flexor digitorum
superficialis

Hypothenar eminence is comprised by abductor digiti
minimi medially, flexor digiti minimijust lateral to it. Deep
to both these lies opponens digiti minimi. ldentify these
three muscles and trace their nerve supply from deep
branch of ulnar nerve.
Between the two eminences of the palm, deep to
palmar aponeurosis, identify the superficial palmar arch
formed mainly by superficial branch of ulnar and
supedicial palmar branch of radial artery. ldentify its
common and proper digital branches.
Clean, dissect and preserve the branches of the
median nerve and superficial division of ulnar nerve in
the palm lying between the superficial palmar arch and
long flexor tendons (Fig. 9.20).
Lying on a deeper plane are the tendons of flexor
digitorum superficialis muscle. Dissect the peculiar
mode of its insertion in relation to that of tendon of flexor
digitorum profundus.
Cut through the tendons of flexor digitorum super-
ficialis 5 cm above the wrist. Divide both ends of
superficial palmar arch. Reflect them distally towards
the metacarpophalangeal joints.
ldentify four tendons of flexor digitorum profundus
diverging in the palm with four delicate muscles, the
lumbricals arising from them. Dissect the nerve supply
to these lumbricals. The first and second are supplied
from median and third and fourth from the deep branch
of ulnar nerve.
Divide the flexor digitorum profundus^5 cm above
the wrist and reflect it towards the metacarpophalangeal
joints. Trace one df its tendons to its insertion into the
base of distal phalAnx of one finger.

(a) (b) (c)
Figs 9.17a to c: The fibrous flexor sheath and its contents: (a) Bony attachments of the sheath and of the flexor tendons, (b) the
fibrous sheath showing transverse fibres in front of the bones and cruciate fibres in front of joints, and (c) the flexor tendons after
removal of the sheath

Dupuytren's cantracture; This condition is due to
inflammation involving the ulnar side of the palmar
aponeurosis. There is thickening and contraction of
the aponeurosis. As a result, the proxirnal phalanx
and later the middle phalanx become flexed and
cannot be straightened. The terminal phalanx
remains unaffected. The ringfinger ismost commonly
involved (Fig.9.18).

lt
E


=
oCL
CL
f


c
.9
oc)
a
Free download pdf