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Arm Muscles Cheat Sheet (DRAFT) by

Arm muscles + Trps blah

This is a draft cheat sheet. It is a work in progress and is not finished yet.


Origin: Apex of the coracoid process
Insertion: Midway along the medial border of the humeral shaft - Can have slips onto the lesser tuberc­le/­medial epicon­dyl­e/m­edial interm­uscular septum
Nerve: Muscul­ocu­taneous Nerve C5-C7
Action: Flexion and horizontal adduction of the arm

Coraco­bra­chialis - Palpation


- Causes irritation of the muscul­ocu­taneous nerve - C5/C6 lesion spares coraco­bra­chialis
- Related to biceps­(short head), supras­pin­atous, triceps (long head)
- Doorway stretch helps
- Overus­e/i­njuries from chest workou­ts/­any­thing that presses arm tightly towards the body
- Pain in the arm and shoulder down to the back of the hand
- Muscul­ocu­taneous nerve can get trapped


Short: Coracoid Apex
Long: Suprag­lenoid Tubercle of the scapula
Insertion:Posterior Radial Tuberosity
Nerve: Muscul­ocu­taneous (C5-6)
Action: Flexion of the elbow and arm, supination of forearm

Biceps Brachii - Palpation


- Causes superf­icial anterior shoulder pain
- Infras­pin­atous causes satellite Trps in Biceps
- Pincer type action with patient's arm bent - difference between biceps and brachialis
- Tender in adhesive capsulitis (long head reinforces GH capsule)
- Antagonist = triceps


Origin: Lower 1/2 of the front of the humerus + interm­uscular septa
Insertion: Ulnar Tuberosity + Anterior aspect of the coronoid process
Nerve: Muscul­ocu­taneous Nerve C5-C6 + Radial Nerve C7
Action: Flexion of the elbow

Brachialis Palpation


- Palpation - push the biceps medially with the forearm pronated
- Aggravated by repeated overhead lifting


Long Head: Infrag­lenoid Tubercle of scapula + GH capsule
Lateral Head: Posterior surface of humeral shaft + lateral interm­uscular septum, above radial groove
Medial head: Posterior surface of humeral shaft, below radial groove + medial interm­uscular septum + lower part of lateral interm­uscular septum
Insertion: Posterior olecranon
Nerve: Radial Nerve C6-C8
Action: Extension of the elbow + extension of the shoulder (long head)

Triceps - Palpation


- Causes posterior upper arm and shoulder pain (usually hard to localise)
- Consider radial nerve entrapment at the Arcade of Frohse
- Can mimic C7 radicular pain


Origin: Posterior surface of the lateral epicondyle of the humerus
Insertion: Lateral aspect of the Olecranon + proximal quarter of the posterior surface of the shaft of the ulna
Nerve: Radial C6-C8
Action: Elbow extension

Anconeus - Palpation


Pronator Teres

Humeral: Proximal medial epicondyle - CFO and interm­uscular septum
Ulnar: Medial side of coronoid process of the ulna
Insertion: Lateral surface of radial shaft
Nerve: Median nerve (C6-7)
Action: Pronation of the forearm + weak flexor of the elbow

Pronator Teres - Palpation

Pronator Teres - Trps

- Mimics Carpal Tunnel
- TrPs can be activated by broken wrist/­elbow

Flexor Carpi Radialis

Origin: Medial Epicondyle (CFO) + Antebr­achial Fascia + interm­uscular septa
Insertion: Palmer Surface of the base of the 2nd metaca­rpal, slip into 3rd metacarpal
Nerve: Median Nerve (C6-7)
Action: Flexion and radial deviation of the wrist


- Pectoralis minor can cause satellite trigger points in FCR

Flexor Carpi Ulnaris

Humeral Head: Medial Epicondyle CFO
Ulnar: Medial Margin of the olecranon and proximal 2/3rds of the posterior border of the ulna
Insertion: Pisisform, Hamate, 5th metacarpal - can be attached to the flexor retina­culum + 4th and 5th metacarpal
Nerve: Ulnar Nerve (C7-T1)
Action: Flexion and ulna deviation of the wrist


- Satellite Trps in Pecs minor, Lats, serratus posterior superior
- Can entrap ulna nerve

Palmaris Longus

Origin: Medial Epicondyle (CFO) + Interm­uscular septa and deep fascia
Insertion: Palmar Aponeu­rosis
Nerve: Median Nerve (C7-8)
Action: Anchors the skin and fascia of the hand improving grip strength and flexion of the wrist


- Trps can cause difficulty in handling tools - tenderness in palm
- Trps in Triceps medial head causes satellite Trps in PL


Origin: Proximal 2/3rds of suprac­ondylar ridge of the humerus, lateral interm­uscular septum
Insertion: Lateral side of the distal end of the radius
Nerve: Radial (C5-6)
Action: Flexion of the elbow - especially when forearm is in mid pronation

Brachi­ora­dialis - Palpation


Flexor Digitorum Superf­icialis

Medial Epicondyle of the humerus (CFO) + anterior band of the ulnar collateral ligament + interm­uscular septa, medial side of the coronoid process, radial head
Insertion: Base of the middle phalanges of the finger
Nerve: Median Nerve C8-T1
Action: Flexion of the interp­hal­angeal, metaca­rpo­phageal and wrist joints


Flexor Digitorum Profundus

Origin: Upper 3/4 of anterior and medial surfaces of the ulna, medial side of coronoid process, upper 3/4s of posterior ulnar boder + anterior surface of intero­usseous membrane (ulnar half)
Insertion: Palmar surfaces of bases of distal phalanges
Medial part (Middle and Ring Finger): Ulnar Nerve C8-T1
Lateral part (Middle and Index finger) Median Nerve C8-T1
Action: Flexion of fingers - DIPs


- Same as FDS (See above)

Flexor Pollicis Longus

Origin: Anterior surface of the radius + intero­sseous membrane - can originate from slip from the latera­l/m­edial border of coronoid proces­s/m­edial epicondyle of the humerus
Insertion: Palmar surface of the base of the distal phalanx of the thumb
Nerve: Anterior intero­sseous branch of the median nerve (C7-8)
Action: Flexion of the phalanges and metaca­rpo­pha­langeal joint of the thumb

FPL - Palpation



Origin: Proximal 1/3rd of the radius , lateral epicon­dyle, radial collla­teral ligament, annular ligament, supinator crest and posterior part of the triangular depression in front of it
Insertion: Lateral surface of proximal 1/3rd of radius
Nerve: Posterior Intero­sseous Nerve (radial) (C6-7)
Action: Supination

Supinator - Palpation


- Lateral Elbow pain producer
- Deep radial nerve can be entraped by tight supinator (Resisted extension of middle finger with wrist straight causes pain)

Pronator Quadratus

Origin: Anterior surface of the shaft of the ulna, medial part of the surface, aponeu­rosis
Insertion: Distal quarter of the anterior border and surface of the shaft of the radius - deep fibres insert into the triangular area above the ulnar notch of the radius
Nerve: Anterior osseous branch of the median nerve (C7-8)
Action: Pronator

Pronator Quadratus - Palpation

- Radial artery + styloid process
- Get pt to flex and supinate wrist - relax tendons
- Get pt to pronate slightly


Extensor Carpi Radialis Longus

Origin: Distal third of lateral suprac­ondylar ridge of the humerus + lateral interm­uscular septum
Insertion: Radial side of the dorsal surface of the base of the second metacarpal -can have slips to the 1st/3rd metacarpal
Nerve: Radial Nerve (C6-7)
Action: Extension and radial deviation of the wrist


- TrPs in scalenes and supras­pin­atous can lead to satellite TrPs in ECR Longus and Brevis
- TrPs are activated in ECR longus, ECR brevis and brachi­ora­dialis by reptative gripping

Extensor Carpi Radialis Brevis

Origin: Lateral epicondyle of humerus + interm­uscular septa
Insertion: Dorsal Surface of third metaca­rpal, distal to the styloid process
Nerve: Posterior Intero­sseous Nerve (radial) (C7-8)
Action: Extension and Radial Deviation of the wrist

ECRB + ECRL - Palpation


- Can entrap Radial Nerve
- Thickest part of muscle belly most common site for trigger points

Extensor Digitorum

Origin: Lateral Epicondyle of the humerus (CEO) + adjacent interm­uscular septa + antebr­achial fascia
Insertion: Dorsum of proximal phalanges
Nerve: Posterior intero­sseous nerve (C7-8)
Action: Extension of Wrist, metaca­rpo­pha­langeal , proximal and distal interp­hal­angeal joints

Ext Digitorum - Palpation


- Can refer pain to lateral epicondyle
- Middle finger commonly affected

Extensor Digiti Minimi

Origin: CEO + Interm­uscular septa + antebr­achial fascia
Insertion: Dorsal digital expansion of the 5th digit - can be a slip onto the 4th
Nerve: Posterior Intero­sseous Nerve (C7-8)
Action: Extension of the little finger and wrist
- Trps same as Extensor Digitorum
- Antagonist - Flexor digiti minimi brevis

Extensor Carpi Ulnaris

Humeral: Lateral epicon­dyleof the humerus
Ulnar: CEO, Posterior border of the ulna, antebr­achial fascia
Insertion: Tubercle on the medial side of the fifth metacarpal base
Nerve: Posterior Intero­sseous Nerve C7-8)
Action: Extension and ulnar deviation of the wrist


ECU - Palpation