Download Anterior Compartment Fore arm - By Dr Nand Lal Dhomeja

THE MUSCLES OF THE ANTERIOR
COMPARTMENT OF FOREARM AND
FLEXOR RETINACULUM
LEARNING OBJECTIVES
At the end of the lecture, the student should be able to:
 Describe the muscles of forearm.
 Tell the nerve supply of these muscles.
 Explain actions of the muscles of anterior compartment of forearm.
 Describe attachment and functions of flexor retinaculum
MUSCLES OF THE ANTERIOR
COMPARTMENT OF FOREARM
Arranged in two Groups.
 Superficial Group of Muscles.
 Deep Group of Muscles.
SUPERFICIAL MUSCLES
 Pronator teres.
 Flexor carpi radialis.
 Flexor digitorium superficials.
 Palmaris longus.
 Flexor carpi ulnaris.
DEEP MUSCLES
 Flexor digitorium profundus.
 Pronator quaradatus.
 Flexor pollicis longus.
SUPERFICIAL MUSCLES
Have a common origin.
Arise from anterior surface of medial epicondyles.
Three have additional origin also i.e.
Pronator teres,
flexor carpi radials,
flexor digitorium superficials.
PRONATOR TERES
Origin :
A. LARGE SUPERFICIAL HEAD:
1. Common origin.
2. Supra condylar ridge.
B. SMALL DEEP HEAD:
From medial border of the coronoid process of ulna just distal to the tubercle
on it.
Insertion :
By flat tendon into the middle of lateral surface of shaft of radius at its most
prominent part of its outward convexity.
PRONATOR TERES
NERVE SUPPLY:
Muscular branches of
median nerve.
PRONATOR TERES
ACTION:
 Pronates the forearm.
 Weak flexor of elbow
FLEXOR CARPI RADIALIS
ORIGIN:
 Common origin.
 Fleshy turn in to long tendon.
 Grooves trapezium.
INSERTION :
On the bases of 2nd and 3rd metacarpals.
NERVE SUPPLY:
median nerve.
FLEXOR CARPI RADIALIS
Actions:
 Flexor and radial abductor of the wrist.
 It is stabilizer of the wrist
FLEXOR DIGITORIUM SUPERFICIALIS
ORIGIN:
 Common origin
 Medial ligament of the elbow.
 Tubercle of the coronoid process of ulna (sublime tubercle).
 Fibrous arch continues the origin across the radius from whole length of
anterior oblique line.
Insertion:
 Enters the fibrous flexor sheath.
 divides in two halves
 attached to the margins of the front of the middle phalanges.
FLEXOR DIGITORIUM SUPERFICIALIS
Nerve supply: Median nerve(7,8).
Action: flexor of proximal interphalangeal joints, metacarpophalangeal joints, wrist joint
and assists in flexion of elbow.
PALMARIS LONGUS
ORIGIN:
 Common origin.
 Broadens as it passes flexor retinaculum to which it is partially adherent.
 It slits to form longitudinally directed fibers.
Action:
 weak flexor of wrist.
 Anchors the skin and fascia of hand.
FLEXOR CARPI RADIALIS
ORIGIN:
 common origin.
 Wide apponeurosis from the medial border of olecronon process and
subcutaneous border of ulna.
 Ulnar nerve lies between humeral and ulnar head.
INSERTION:
 on the pisiform and end by the pisohamate and pisometacarpal ligament
into the hamate and 5th metacarpal.
FLEXOR CARPI RADIALIS
NERVE SUPPLY:
Ulnar nerve (C7,8).
ACTION:
It is flexor and ulnar adductor of wrist.
Deep muscles
FLEXOR DIGITORIUM PROFUNDUS
ORIGIN:
•
Medial surface of the olecronon.
•
Upper three quarters of anterior and medial surface of ulna (including its
subcutaneous border and interosseus membrane).
Tendon of the index finger separates in the forearm.
•
INSERTION:
• At the base of terminal phalanges of fingers.
NERVE SUPPLY:
• Anterior interosseus branch of median nerve and ulnar nerve
(C 8,T1 little finger side).
ACTION:
• Flexes terminal interphalangeal joint.
• Great gripping muscle.
FLEXOR POLICIS LONGUS
ORIGIN:
Anterior surface of the of the radius below the oblique line and above the
insertion of Pronator quaradatus and from interosseus membrane. Tendon forms
on ulnar side.
•
Passes underneath the flexor retinaculum.
INSERTION:
• at the base of first distal phalanx.
NERVE SUPPLY:
• Anterior interosseus branch of median nerve (C6,7).
ACTION:
• Flexor of interphalangeal joint of thumb.
• Also flexes metacarpophalangeal joint and carpometacarpophalangeal joints of thumb
and wrist joint.
PRONATOR QUARADATUS
ORIGIN:
• From a ridge on anterioromedial aspect of ulna.
INSERTION:
• Anterior surface of lower fourth of radius and triangular area above ulnar
notch.
PRONATOR QUARADATUS
NERVE SUPPLY:
Anterior interosseus branch of median nerve.
ACTION:
Pronates the forearm and help to hold lower end of radius and ulna together.
FLEXOR RETINACULUM
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Strong fibrous band.
Lies across the carpus bones at proximal part of hand.
ATTACHED TO THE,
Hook of hamate and pisiform medially.
Tubercle of the scaphoid and ridge of trapezium laterally.
• As carpal bones are concave so flexor retinaculum forms carpal tunnel.
• Median nerve and long flexor tendons pass through the capal tunnel.
• Superficialis tendon pass through in two separate rows, middle and ring
fingers in frontof the index and Little fingers tendons.
CARPAL TUNNEL SYNDROME.
• Median nerve pass deep between flexor digitorium superficialis flexor
carpi radialis when it is liable to compression causing carpal tunnel
syndrome.