There are a lot of structures in your upper limb (note that in medical term; arm, forearm and hand means differently from the common usage).
I would like to introduce you on how I remember the names of important muscles and bones in the upper limb. There are various mnemonics created by medical students around the world to master the field of anatomy.
I used this mnemonic;
Stop Letting Those People Touch The Cadaver's Hand.
From lateral to medial;
Proximal row - Scaphoid, Lunate, Triquetrum and Pisiform
Distal row - Trapezium, Trapezoid, Capitate and Hamate.
To differentiate trapezium and trapezoid, remember that Trapezium is at Thumb, hence the most lateral bone in distal row of carpal bones.
Extensor muscles of forearm
Rule of 3
3 muscles for wrist extension
- Extensor carpi radialis brevis
- Extensor carpi radialis longus
- Extensor carpi ulnaris
3 muscles for finger extension
- Extensor digitorum ( for all four fingers)
- Extensor indicis
- Extensor digiti minimi
3 muscles for thumb
- Extensor pollicis longus
- Extensor policis brevis
- Abductor pollicis longus
All extensor muscles of forearm are supplied by radial nerve. Injury to radial nerve caused the classical wrist drop due to unopposed flexor muscles :)
Flexor muscles of forearm.
Place your thumb at the palm and put this at your contralateral forearm at your medial epicondyle with your middle finger pointing towards the thumb distally. The forearm must be in supine position.
Your thumb will be below the palm and four fingers will be pointing towards the hand. This represents the layers in flexor muscles in the forearm.
Say PFPF. The first P in your index finger is Pronator Teres. F is for flexor carpi radialis (the middle finger point towards radial bone, hence radialis). The next P is for palmaris longus and F is for flexor carpi ulnaris.
The thumb is for flexor digitorum superficialis.
There are 3 layers in the flexor compartment. The muscles in the deep layer are flexor digitorum profundus (FDP), flexor pollicis longus and pronator quadratus.
All flexor muscles of forearm are supplied by median nerve except one and half. They are flexor carpi ulnaris and half of flexor digitorum profundus.
Muscles of the hand
PAD DAB - palmar hand muscles adduct, dorsal hand muscles abduct
Thenar and hypothenar muscles
All For One And One For All (medial to lateral)
Abductor digiti minimi, Flexor digiti minimi, Opponens digiti minimi, Adductor pollicis, Opponens Pollicis, Flexor Pollicis Brevis, Abductor pollicis brevis
All intrinsic muscles of the hand are innervated by ulnar nerve except these muscles which are innervated by the median nerve
Lateral 2 lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis