Anatomy UpperLimbMuscles
Anatomy UpperLimbMuscles
Anatomy UpperLimbMuscles
Supraspinatus
Course: med 2/3 supraspinatous fossa → high ant greater tuberosity
Action: initiates abduction
Nerve and artery: suprascapular
Infraspinatus
Course: infraspinatous fossa → middle post greater tuberosity
Action: laterally rotates arm
Nerve and artery: suprascapular
Subscapularis
Course: med 2/3 subscapular fossa → ant lesser tuberosity
Action: medially rotates arm, extension
Nerve: upper and lower subscapular Artery: subscapular
Teres Minor
Course: mid 1/3 lat border scapula → low post greater tuberosity
Action: lat rotates arm
Nerve: axillary Artery: circumflex scapular
Pectoralis Major
Clavicular head: med clavicle → lat lip bicipital groove
Sternocostal head: manubrium, sternum, 2-6 costal cartilages,
aponeurosis of ext oblique. Inserts via bilaminar tendon
Action: flex, adduct, int rotate
Nerve supply: lat/med pectoral nerves (5 segments plexus)
Artery: pectoral branch thoracoacromial trunk
Pectoralis Minor
Course: ribs 3-5 → coracoid
Action: scapula forward, medial, down
Nerve: medial pectoral
Artery: pectoral branch thoracoacromial trunk
Deltoid
Course: lat 1/3 clav, acromion, lower spine scapula → deltoid tub
Action: abducts, flex/extend, med/lat rotate
Nerve: axillary
Artery: post circumflex humeral
Serratus Anterior
Course: ribs 1-9 → med aspect of costal surface scapula
Action: protraction and lat rotation scapula
Nerve and artery: long thoracic
Subclavius
Course: 1st rib → inf mid 1/3 clavicle Nerve: nerve to subclavius
1
Anterior arm
All nerve = musculocutaneous (C5-6); all artery = brachial
Biceps brachii
Long head: supraglenoid tub, intertub groove → radial tub/bicip aponeurosis
Short head: coracoid (lat to coracobrach) → radial tub/bicipital aponeurosis
Action: flex shoulder (long head) and elbow, supinates (best elbow flexed)
Factoid: supination more powerful when elbow flexed
2 heads unite just distal to 1/2 way down arm
no attachment to humerus, acts on 3 joints
longs head is intracapsular but extrasynovial
Brachialis
Course: ant lower ½ hum/intermusc sept/supracond ridge → ulnar coronoid process/tubercle
Action: flexes elbow (MAIN flexor)
Coracobrachialis
Course: coracoid (med to biceps) → ant/med midshaft humerus
Action: adduct/flex shoulder
Pierced by musculocutaneous nerve
Posterior Arm
Triceps
Long head: infraglenoid tubercle → descends between teres minor/major
Lateral head: postlat humerus/lat intermuscular septum
Anconeus
Course: lat epicondyle humerus → lat olecranon
Action: extends elbow
Nerve: nerve to anconeus Artery: interosseous recurrent
1. FDS
Humeroulnar head: med epicondyle → shafts MP’s
Radial head: mid 1/3 radius → shafts MP's
Action: flexes MCP and PIPJ's
Factoid: median nerve/ulnar artery pass between 2 heads
2. FCU
Humeral head: med epicondyle
Ulnar head: med olecranon/upper 2/3 shaft post ulna
Both to pisiform; via ligs to hook hamate, base 5th MC
Action: flexes wrist, adducts hand
Factoid: ulnar artery/nerve passes between 2 heads
3. FCR
Course: medial epicondyle humerus → bases 2nd + 3rd MC's
Action: flexes wrist, abducts hand
Factoid: tendon begins mid forearm, pierces flexor retinaculum, passes thru groove in trapezium in own sheath
2
4. Palmaris Longus
Course: med epicondyle → palmar aponeurosis
Action: flexes wrist
5. Pronator Teres
Humeral head: med → lat midshaft radius
Action: pronation, adducts radius
Factoid: less powerful pronator than pronator quadratus
Median nerve passes between 2 heads; ulnar artery NOT between 2 heads
Deep:
All artery and nerve = Ant IO branch med, plus FDP also ulnar
1. FDP
Course: post border/prox 2/3 med border ulnar and IO membrane → base DP’s
Action: flexes MCP, PIP and DIPJ's
Factoids: does NOT arise from radius
origins of lumbricals arise from tendons
most powerful and bulky muscle of forearm; incr action by wrist extension
tendon for IF separates from others in forearm
2. FPL
Course: ant radius and IO membrane → base DP T
Action: flexes MCP and IPJ
Factoid: only muscle that flexes IPJ of T; separate synovial sheath in carpal tunnel
3. Pronator Quadratus
Course: from ant lower 1/3 shaft of ulna → ant lower 1/3 shaft radius
Space of Parona:
in front of pronator quadratus, deep to long flexor tendons fingers
limited proximally by oblique origin of FDS
proximal parts of flexor synovial sheaths protrude into it
can become involved in synovial sheath infections
Order from ulnar to radial:
FCU... UN... UA... FDS... PL... MN... FCR... RA... Brachioradialis... sup rad nerve
1. Brachioradialis
Course: lat supracondylar ridge upper 2/3 humerus/lat IM septum → lat styloid process radius
Action: flexes elbow, pro/supination
Factoid: overlapped by AbPL and EPL in lower forearms; overlies radial N/art as lie on supinator
3
2. ECU
Humeral Head: lat epicondyle humerus → med base of MC of LF
Ulnar Head: mid 1/2 post ulna → med base of MC of LF
Action: extends wrist, adducts hand
Factoid: tendon runs in groove between ulnar head/ulnar styloid
3. ECRB
Course: lat epicondyle, radial collat lig, aponeurosis, IM septa → post base
MC of MF
Action: extends wrist, abducts hand
Factoid: covered by ECRL; overlapped by AbPL, EPB, EPL in lower
forearm; immediately behind radial styloid
4. ECRL
Course: from lower 1/3 lat supracondylar ridge humerus and lat IM septum →
post base MC of IF
Action: extends wrist, abducts hand
Factoid: overlapped by AbPL, EPB and EPL in lower forearm
becomes tendon in upper 1/3 forearm
lies immediately behind radial styloid
5. EDM
Course: lat epicondyle and IM septum → extensor expansion LF
Action: extends MCP, PIP and DIPJ LF
Factoid: lies medial to respective ED
6. ED
Course: from lat epicondyle humerus → extensor expansions
Action: extends MCP, PIP and DIPJ's, extends wrist
7. Anconeus
1. Extensor Indicis
Course: IO membrane and postlat distal ulna → extensor expansion IF
Action: extends MCP, PIP and DIPJ IF
2. Supinator
Course: lat epicondyle, rad collat/ulnar ligs/crest ulna → prox 1/3 radius
Factoid: humeral head more superficial/vertical than ulnar head
Post IO nerve passes between 2 heads; forms floor of antecubital fossa
3. EPB
Course: IO membrane and post distal radius → base PP T
Action: extends MCPJ T
4. EPL
Course: IO membrane and mid postlat ulna → base DP T
Tendon passes med to tubercle of radius and uses as pulley
Action: extends IPJ thumb
Factoid: boundary of ASB
5. AbPL
Course: mid 1/3 post radius/IO membrane/postlat mid ulnar → radial
base MC T
Action: abducts T at CMCJ
4
Thenar Muscles
All nerve = recurrent branch of median C8/T1; All artery = sup palmar branch of radial
1. FPB
Origin: superficial head from flexor retinaculum/trapezium, deep head from trapezoid/capitate
Insertion: radial sesamoid and radial side base prox phalanx of thumb
Action: flexes CMC and MCPJ of thumb
2. AbPB
Origin: flexor retinaculum, scaphoid tubercle and trapezium
Insertion: radial side of base proximal phalanx of thumb
Action: abducts thumb
3. OP
Origin: flexor retinaculum and trapezium
Insertion: whole of radial side of 1st MC
Action: opposes thumb (medially rotates and flexes)
Hypothenar Muscles
All nerve = deep branch of ulnar; All artery = ulnar
Interossei
Palmar (4): ant/inner aspects shafts MC's; smaller than dorsal; unipennate
Dorsal (4): post/inner aspects shafts MC's; 2 heads – one from each metacarpal
Insertion: extensor expansions and proximal phalanx of respective finger
Action: flex MCPJ, extend IPJ (created by palmer adduction and dorsal abduction - PAD, DAB)
Nerve supply: deep branch of ulnar C8/T1
Artery: dorsal and palmar metacarpal
Lumbricals
Origin: each of 4 FDP tendons
Insertion: passes along radial side of corresponding MCPJ on palmer surface of deep transverse MC ligament
Ulnar lumbricals bicipital, median lumbricals unicipital. Inserts into extensor expansion on dorsum of first phalanx.
Action: weakly flex MCPJ, extend IPJ
Nerve: deep branch ulnar except lat 2 = median
Artery: sup palmar arch
Factoid: 1st/2nd unipennate - from lateral side and 1st and 2nd FDP tendons
3rd/4th bipennate (eg. 3rd lumbrical from lat ring finger and med middle finger FDP tendon)
5
Finger flexion/extension
ED → extends all joints
FDP → flex DIP and MCP
FDS → flex PIP and MCP
Lumbricals → flex MCP, ext IPJs
Dorsal int → abduct; palmar int → adduct → together flex
Hand muscles
All For One And One For All (Med → lat: AbDM,FDM, ODM, AdP, OP, FPB, AbPB)