Median Nerve & Cubital Fossa Flashcards
Median nerve is formed by
Two roots;
Medial root (Medial cord) Lateral root (Lateral cord)
Median nerve is crossing the brachial artery from which side
From the lateral side to the Medial side
Most medial structure of Cubital Fossa;
Median Nerve
How Median nerve enters the Forearm?
And it supplies?
By passing between the Heads of Pronator teres muscle
Supplies the Flexors of Forearm
List Superficial Flexors of Forearm;
- Pronator teres
- Flexor carpi radialis
- Palmaris longus
- Flexor carpi ulnaris
- Flexor digitorum superficialis
Superficial flexors of forearm takes origin from;
Medial Epicondyle
Action of Pronator teres;
Pronation
Action of Flexor carpi radialis;
- Flexion of Wrist
- Radial Deviation
Action of Palmaris longus;
Its continuation in the palm as
Flexion of Wrist
As Palmar Aponeurosis
Action of Carpi Ulnaris;
- Flexion of wrist
- Ulnar deviation
Attachment and Action of Flexor digitorum superficialis;
It is attached upto Middle phalanx
Flexion of →
- Wrist
- MCP Joint
- Proxima IP Joint
Median Nerve directly supplies only Four Muscles;
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
Anterior Interosseus Nerve (branch of Median Nerve) supplies;
2 1/2 Muscles;
- Pronator Quadratus
- Flexor policis longus
- Lateral 1/2 of Flexor digitorum profundus
List Deep flexors of forearm;
- Flexor digitorum profundus
- Flexor policis longus
- Pronator quadratus
Action of Flexor digitorum profundus;
Flexion of →
- Wrist
- MCP Joint
- Proximal and Distal IP Joint
Lumbrical muscles take origin from ←
Tendon of Flexor digitorum profundus
Ulnar nerve supplies;
1 1/2 Muscles in the forearm;
Flexor carpi ulnaris (superficial)
Medial 1/2 of Flexor digitorum profundus (deep)
What is Gantzers muscle
In some pateints;
If Flexor pollicis longus have an Accessory Head → called as Accessory Head of Flexor Pollicis Longus
AHFPL
If AHFPL is present it compresses →
Anterior Interosseous Nerve
Jersey finger is due to
Avulsion of Flexor digitorum profundus (FDP) tendon
→ causes loss of flexion of Distal IP Joint
Caused by Violent traction on flexed distal phalanx, as in catching on jersey of running football player
Median nerve enters the palm by passing
Below the Retinaculum
Median nerve in the palm is divided into
Medial and Lateral Branch
Before dividing Median nerve gives one Motor Branch →
And it supplies →
Recurrent Branch
Supplies → Thenar Eminence Muscles
The branch of median nerve passing above the Flexor Retinaculum and it Supplies
Palmar branch of Median Nerve
Gives sensory supply to Thenar Eminence
Proper Palmar Digital Branch supplies;
Sensory Supply to
- Lateral 3 1/2 digits on the Palmar side
- Distal and Middle Phalanx of the lateral 3 1/2 digits
Supination of Forearm done by;
Supinator → supplied by Posterior Interosseous nerve
Biceps brachii → Supplied by Musculocutaneous nerve
MC affected nerve in Wrist Slash Injury;
Median Nerve
Due to inflicted cut in the distal forearm (wrist regoin)
Intact muscles and functions in Wrist slash injury;
- All the forearm flexors which are supplied by Median Nerve will be Normal
- On Wrist flexion - no ulnar deviation
- Pronation not affected
- FDP Lateral 1/2 and FDS →
No Benediction hand deformity
No Pointing index finger
Function lost in Wrist slash injury;
LOAF Muscles paralysed →
atrophy of the thenar muscle →
Ape thumb deformity
Loss of sensation over the Lateral 3 1/2 digits + Thenar eminence
Compression of Median nerve while passing below the Flexor Retinaculum → result into
Carpal tunnel syndrome
Features are same as Wrish slash injury except → Sensory supply over Thenar Eminence is Normal
Why in carpal tunnel syndrome sensation over Thenar Eminence is normal
Because Palmar Cutaneous branch of Median Nerve passes above the Flexor Retinaculum
Boundaries of Cubital Fossa;
Medially -
Laterally -
Apex -
Base -
Medially - lateral border of Pronator teres
Laterally - medial border of Brachioradialis
Apex - meeting point of brachioradialis and pronator teres
Base - imaginary line connecting the two Epicondyle
Roof of Cubital Fossa is formed by
- Bicipital aponeurosis- derided from biceps tendon
* Median cubital vein
Floor of Cubital fossa is formed by
- Brachialis muscle
* Supinator muscle
Contents of Cubital Fossa -
M
B
B
S
M- Medial nerve
B- Brachial artery
B- Biceps tendon
S- Superficial branch of Radial Nerve