Human Anatomy Vol 1

Pefsfioms

The structures passing superficial to the flexor retina-

culum are:

i. The palmar cutaneous branch of the median

nerve.

ii. The tendon of the palmaris longus.

iii. The palmar cutaneous branch of the ul:rar nerve.

iv. The ulnar vessels.

v. The ulnar nerve. The thenar and hypothenar

muscles arise from the retinaculum (Fig. 9.15).

The structures passing deep to the flexor retinaculum

are:

i. The median nerve.

ii. Four tendons of the flexor digitorum superficialis.

iii. Four tendons of the flexor digitorum profundus.

iv. The tendon of the flexor pollicis longus.

v. The ul-nar bursa.

vi. The radial bursa.

vii. The tendon of the flexor carpi radialis lies between

the retinaculum and its deep slip, in the groove

on the trapezium (Fig. 9.15).

Polmor Aponeurosis

This term is often used for the entire deep fascia of the
palm. However, it is better to restrict this term
to the central part of the deep fascia of the palm which
covers the superficial palmar arch, the long flexor
tendons, the terminal part of the median nerve, and
the superficial branch of the ulnar nerve (Fig. 9.16).

Feofures

Palmar aponeurosis is triangular in shape. Tlne apex
which is proximal, blends with the flexor retinaculum
and is continuous with the tendon of the palmaris
longus. The base is directed distally. It divides into

Palmar cutaneous

branch of ulnar nerve

Palmaris longus

Palmar cutaneous

branch of median nerve

Median nerve

Volar carpal ligament

Ulnar artery and nerve

FOBEAHM AND HAND

Palmaris longus

tendon

Ulnar nerve and artery

Palmar cutaneous

branch of ulnar nerve

and flexor retinaculum

Palmar cutaneous

branch of median

Palmar aponeurosis

Digital vessels

and nerves

Fibrous flexor sheath

Terminal phalanx

Fig.9.16: The deep fascia of the hand forming the flexor

retinaculum, palmar aponeurosis and fibrous flexor sheaths

superficial and deep strata, superficial is attached to

dermis. Deep strata divides into four slips opposite the

heads of the metacarpals of the medial four digits. Each

slip divides into two parts whiclr are continuous with

the fibrous flexor sheaths. Extensions pass to the deep

transverse metacarpal ligament, the capsule of the

metacarpophalangeal joints and the sides of the base

of the proximal phalanx. The digital vessels and nerves,

and the tendons of the lumbricals emerge through the

intervals between the slips. From the lateral and medial

margins of the palmar aponeurosis, the lateral and

medial palmar septa passbackwards and divide the palm

into compartments.

Falmcfions

Palmar aponeurosis fixes the skin of the palm and thus

improves the grip. It also protects the underlying

tendons, vessels and nerves.

Fibrous Flexor Sheoths of lhe Fingers

The fibrous flexor sheaths are made up of the deep

fascia of the fingers. The fascia is thick and arched. It is

attached to the sides of the phalanges and across the

base of the distal phalanx. Proximally, it is continuous

with a slip of the palmar aponeurosis.

In this way, a blind osseofascial tunnel is formed

which contains the long flexor tendons enclosed in the

digital synovial sheath (Figs9.17a to c). The fibrous

sheath is thick opposite the phalanges and thin opposite

the joints to permit flexion.

The sheath holds the tendons in position during

flexion of the digits.

Hypothenar

muscles

Tendons oi

flexor digitorum

superficialis

Ulnar bursa

Fig. 9.15: Flexor

Thenar

muscles

Thenar

muscles

Flexor carpi

radialis

Flexor pollicis longus

and radial bursa

Tendons of fl exor digitorum

profundus with lumbricals

,ci

F

o

CL

e

o

oo

retinaculum with its relations a