Anatomy of Radial nerve .pptx (I BHMS))

Short ppt about the anatomy of radial nerve.Radial nerve is the largest branch of posterior cord of brachial plexus.It is also the thickest branch of brachial plexus.The only branch which has all root value C5 ,C6,C7,C8,T1.


In the following presentation,

Introduction
Course
Branch and distribution
Muscle innervation
Cutaneous innervation
Sensory functions
Clinical anatomy
Saturday night palsy
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Are given shortly.

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1. Radial nerve
Jaru V J Joseph
I BHMS(Jr)

2. Introduction
•Thickest branch of brachial plexus
•Largest branch of posterior cord
•Its root value of C5,C6,C7,C8,T1.

3. COURSE
•The radial nerve is the terminal continuation of theposterior cordof
thebrachial plexus. It therefore contains fibresfrom nerve roots C5 –T1.
•The nerve arises in theaxillaregion, where it is situatedposteriorly to
theaxillary artery. It exits the axilla inferiorly (via the triangular interval),
and supplies branches to the long and lateral heads of thetriceps brachii.
•The radial nerve then descends down the arm,travelling in a shallow
depression within the surface of thehumerus, known as theradial groove.

4. •As it descends, the radial nerve wraps around the humerus
laterally, and suppliesa branch to the medial head of the
triceps brachii. During much of its course within the arm, it
is accompanied by the deep branch of thebrachial artery.
To enter the forearm, the radial nerve travels anterior to
thelateral epicondyleof the humerus, through thecubital
fossa. The nerve then terminates by dividing into two
branches:
•Deep branch(motor) –innervates themuscles in the
posterior compartment of the forearm.
•Superficial branch(sensory) –contributes to the cutaneous
innervation of the dorsal hand and fingers.

5. BRANCHES AND ITS
DISTRIBUTION

7. Muscles Innervated by the Radial Nerve:
•Triceps brachii: The radial nerve innervates the long head of the
triceps, contributing to elbow extension.
•Anconeus: This small muscle, located in the posterior aspect of
the elbow joint, is also innervated by the radial nerve.
•Brachioradialis: The radial nerve innervates this muscle, which
assists in flexion at the elbow.
•Extensor Muscles of the Forearm: The radial nerve innervates the
majority of the extensor muscles of the forearm, allowing for
extension of the wrist, fingers, and thumb.

8. MOTOR FUNCTIONS
•The radial nerve innervates the muscles located in the posterior
arm andposterior forearm.
•In the arm, it innervates the three heads of thetriceps
brachii,whichacts to extend the arm atthe elbow. The radial
nerve also gives rise tobranchesthat supply the brachioradialis
and extensor carpi radialis longus (muscles of the posterior
forearm).
•A terminal branch of the radial nerve, thedeep
branch,innervates the remaining muscles of the posterior
forearm.As a generalisation, these muscles act to extend at the
wrist and finger joints, and supinate the forearm.

9. Cutaneous Innervation:
•The radial nerve provides sensory innervation to specific
areas of the arm and forearm through its cutaneous
branches.
•The posterior cutaneous nerve of the arm innervates the
skin on the posterior aspect of the arm.
•The posterior cutaneous nerve of the forearm supplies
sensation to the skin on the posterior aspect of the forearm
and hand.

11. SENSORY
FUNCTIONS
•There are four branches of the radial nerve that provide
cutaneous innervation to the skin of the upper limb.
Three of these branches arise in the upper arm:
•Lower lateral cutaneous nerve of arm–Innervates the
lateral aspect of the arm, inferior to the insertion of the
deltoid muscle.
•Posterior cutaneous nerve of arm–Innervates the
posterior surface of the arm.
•Posterior cutaneous nerve of forearm–Innervates a
strip of skin down the middle of the posterior forearm.
•The fourthbranch –thesuperficial branch–is a terminal
division of the radial nerve. It innervates the dorsal
surface of the lateral three and half digits and the
associated area on the dorsum of the hand.

12. CLINICAL ANATOMY

13. SATURDAY NIGHT
PALSY
Occur due to prolonged pressure on
the nerve. It typically happens when
someone falls asleep in an awkward
position, compressing the radial
nerve against a hard surface, such as
a chair armrest or the edge of a desk.
This compression leads to temporary
paralysis or weakness of the muscles
innervated by the radial nerve,
resulting in symptoms such as
difficulty extending the wrist, fingers,
and thumb, as well as numbness or
tingling along the back of the hand
and forearm.

14. WRIST DROP
The most common cause of wrist
drop is damage to the radial nerve.
This nerve can be injured by trauma,
such as fractures or dislocations of
the humerus or elbow, compression
(as in Saturday Night Palsy), or
prolonged pressure on the nerve
during sleep or unconsciousness.
Compression of the radial nerve at
various points along its course, such
as in the radial tunnel or at the level
of the axilla, can lead to wrist drop.

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