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This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Muscles, Innervation and the Compartments of the Upper Limb Organized in an Unintentionally Difficult Manner Fascia and compartments of the shoulder PECTORALIS FASCIA - The only contents is Pectoralis Major; Pectoralis fascia continue inferiorly as fascia of the anterior abdominal wall It continues laterally-once it leaves the lateral edge of Pectoralis Major, it becomes AXILLARY FASCIA AXILLARY FASCIA - Continuous with the CLAVIPECTORAL FASCIA Forms the floor of the axilla CLAVIPECTORAL FASCIA - Deep to the Pectoralis major muscle, the CLAVIPECTORAL FASCIA invests the subclavius muscle and pectoralis minor. It forms the costocoracoid membrane above pectoralis minor, and the suspensory ligament of axilla below pectoralis minor. The suspensory ligament drags the axillary fascia upwards when the arm is raised, forming the actual “pit” of the armpit Pectoralis major, wrapped up in pectoralis fascia Clavicle Subclavius Lateral pectoral nerve and Thoracoacromial artery Costocoracoid membrane Pectoralis minor Suspensory ligament of axilla Axillary fascia Axillary fascia Supraspinous, Infraspinous and Subscapular fascia - The supraspinatus, infraspinatus and subscapularis muscles are contained in their own little fascial compartments Deltoid Fascia - The deltoid has its own fascia, continous with the pectoral fascia and infraspinatus fascia It has numerous fascial septa which separate the fascicles of the deltoid Supraspinatus fascia Spine of scapula Clavicle Deltoid fascia Infraspinatus fascia Pectoralis fascia Infraspinatus fascia Subscapularis fascia Fascial septa Pectoralis fascia, infraspinatus fascia and deltoid fascia all continue down the arm to form the brachial fascia This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Anterior Axioappendicular Muscles of the Shoulder There are 3 distinct groups of shoulder muscles: ANTERIOR AXIOAPPENDICULAR MUSCLES – 4 muscles which move the pectoral girdle POSTERIOR AXIOAPPENDICULAR MUSCLES – 4 muscles which attach the upper lumb to the skeleton of the trunk SCAPULOHUMERAL MUSCLES – 6 muscles which act on the glenohumeral joint Pectoralis Minor Anterior Axioappendicular muscles Subclavius All supplied by stupidly different nerves. Pectoralis Major : clavicular head No pattern whatsoever. Pectoralis Major Two heads: - CLAVICULAR HEAD: lateral pectoral nerve o - Pectoralis major: sternocostal head Originates from the medial half of the anterior clavicle STERNOCOSTAL HEAD: medial pectoral nerve Originates from the anterior surface of the sternum, and the first 6 costoclavicular cartilages o Also originates from the aponeurosis of the external oblique muscle of the abdomen INSERTS INTO THE LATERAL LIP OF THE INTERTUBERCULAR GROOVE OF THE HUMERUS o Intertubercular groove of the humerus - - Its inferior border forms the anterior axillary fold o Abducts and medially rotates the humerus o Draws scapula anteriorly and inferiorly by pulling on the humerus The heads can act independently: o Clavicular head alone acts to flex the humerus o When flexed, the sternocostal head extends it from its flexed position. Pectoralis Minor medial pectoral nerve - Serratus Anterior - Innervation Nerve to Subclavius: Off the superior trunk Subclavius Originates at the 3rd, 4th and 5th ribs near the costal cartilages Inserts into the medial border and superior surface of the coracoid process of scapula Its job is to stabilize the scapula by pulling it anteriorly and inferiorly against the chest wall It also assists in elevating the ribs when breathing All the vessels and nerves to the arm travel under the pectoralis minor. Subclavius nerve to subclavius - Lateral Pectoral nerve: Branch of the lateral cord clavicular head of Pectoralis Major - Originates at the junction of the 1st rib and its costal cartilage Inserts into the “groove for subclavius” on the inferior surface of the middle third of the clavicle Depresses and anchors the clavicle Protects the subclavian vessels when the clavicle is fractured Serratus anterior long thoracic nerve - Long Thoracic Nerve: Off the roots of C5, 6 and 7 - Serratus Anterior Medial Pectoral nerve: Branch of the medial cord Pectoralis Minor; sternocostal head of Pectoralis Major - . Originates from the lateral surfaces of the first 8 ribs Inserts into the medial border of scapula Protracts the scapula, holds it against the chest wall, and rotates it superiorly (eg when reaching for something up high). THE MAIN PROTRACTOR OF THE SCAPULA One of the most powerful muscles in the pectoral girdle. Its paralysis causes a winged scapula. Also, the arm cannot be abducted past the horizontal position (the scapula doesn’t rotate upwards anymore) If you insert your chest drain BELOW the mid-axillary line, you will cause this sort of paralysis, which is embarrassing. This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Posterior Axioappendicular Muscles of the Shoulder: the Extrinsic Group There are 2 layers, the superficial and the deep. Posterior Axioappendicular Extrinsic Muscles The superficial group is trapezius and latissimus dorsi The deep group is the levator scapulae and the rhomboids Viewed from above Also supplied by confusingly different nerves. Trapezius spinal accessory nerve - Originates from o o o o o Superior part of Trapesius - Inserts into : o o o - Middle part of Trapesius The external occipital protuberance Nuchal ligament Medial third of superior nuchal line Spinous processes of C spine and T-spine he medial half of the anterior clavicle Lateral third of the clavicle Acromion of scapula Spine of scapula Has 3 distinct parts: Floor of the intertubercular groove, anteriorly on the humerus Middle part of Trapesius SUPERIOR (descending)part which elevates the scapula MIDDLE part which retracts the scapula INFERIOR (ascending) part which depresses the scapula All the parts together act to rotate the scapula superiorly, so the glenoid fossa faces up. T7 Latissimus dorsi Thoracodorsal nerve Latissimus dorsi - - Originates from o Inferior 6 thoracic vertebrae o Thoracolumbar fascia o Iliac crest o Inferior 3 or 4 ribs Inserts into the ANTERIOR surface of the humerus, at the floor of the intertubrercular groove Extends, adducts, medially rotates the humerus Lifts the body up too the arms when climbing Levator scapulae Levator scapulae dorsal scapular and cervical nerves - Rhomboid Minor Rhomboid Major - Innervation Dorsal scapular nerve: Off the roots of C5 Rhomboid major and minor Levator scapulae Originates at the posterior tubercles of the spinous processes of the C1, 2, 3 and 4 vertebrae Inserts into the medial border of scapula, superior to the spine Elevates that corner of the scapula, rotating it so the glenoid cavity faces down Extends the neck (when acting bilaterally) or flexes it laterally (when acting unilaterally) Rhomboid Minor dorsal scapular nerve - Thoracodorsal Nerve: Off the posterior cord - Latissimus dorsi - Originates from the nuchal ligament and the spinous processes of C7 and T1 Inserts into the medial border of the scapula, at the root of the scapular spine Retracts the scapula Rotates the scapula so the glenoid cavity faces down Fixes the scapula to the thoracic wall Rhomboid Major dorsal scapular nerve - . Originates from the spinous processes of T2,3 4and 5 Inserts into the medial border of the scapula, from the root of spine down. Retracts the scapula Rotates the scapula so the glenoid cavity faces down Fixes the scapula to the thoracic wall This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Posterior Axioappendicular Muscles of the Shoulder: the Intrinsic Group with Rotator Cuff muscles These are the deltoid and teres major; and the 4 rotator cuff muscles (teres minor, supraspinatus, infraspinatus and subscapularis) Deltoid Posterior Axioappendicular Intrinsic muscles Again, supplied by totally different nerves. Deltoid axillary nerve - Supraspinatus - Originates from the lateral third of the clavicle, the acromion, and the lateral spine of scapula. Inserts into the deltoid tuberosity of humerus THREE PARTS: Anterior part flexes and medially rotates the humerus o Middle part abducts the humerus o Posterior part extends and laterally rotates the arm o The middle part is multipennate; the others are unipennate It cannot initiate abduction on its own when the arm is fully adducted- thus it needs supraspinatus to initiate the movement. It becomes effective after about 15 degrees of abduction. The deltoid’s anterior and posterior parts swing your arms while walking.it also helps to keep the humeral head in the glenoid fossa. o Infraspinatus Subscapularis Teres Major Teres Minor Iinsertion of deltoid, at the Deltoid Tuberosity - Teres major lower subscapular nerve Deltoid Supraspinatus Deltoid - Originates from the posterior surface of the inferior angle of scapula Inserts into the medial lip of the intertubercular groove of humerus Adducts and medially rotates the arm Also keeps the head of humerus in the socket Rotator Cuff Muscles Whatever other actions they may have, they all help hold the humeral head in the glenoid fossa Supraspinatus suprascapular nerve Infraspinatus - Subscapularis Teres Major Innervation Upper Subscapular nerve Axillary nerve: Off the posterior cord Lower Subscapular nerve Teres Minor Deltoid Subscapularis Subscapularis Teres major Teres Minor Teres Major - Suprascapular nerve Supraspinatus Infraspinatus Originates in the supraspinous fossa of the scapula Inserts into the superior facet of the greater tubercle of humerus Initiates abduction, and assists the deltoid with abduction of the arm; its the only one that doesn't rotate the arm. Infraspinatus suprascapular nerve - Originates in the infraspinous fossa of the scapula Inserts into the middle facet of the greater tubercle of humerus Laterally rotates the arm Teres Minor axillary nerve - Originates from the middle of the lateral border of scapula Inserts into the inferior facet of the greater tubercle of humerus Laterally rotates the arm Subscapularis upper and lower subscapular nerves - . Originates in the subscapular fossa Inserts into the lesser tubercle of humerus Medially rotates and abducts the arm This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Muscles and Nerves involved in the movements of the shoulder joint flexion: pectoralis major (clavicular head) – medial and lateral pectoral nerve deltoid (anterior part) – axillary nerve coracobrachialis – musculocutaneous nerve biceps femoris– musculocutaneous nerve extension: deltoid (posterior part) – axillary nerve teres major– lower subscapular nerve abduction: deltoid (central part) – axillary nerve supraspinatus– suprascapular nerve adduction: pectoralis major – medial and lateral pectoral nerve latissimus dorsi – thoracodorsal nerve subscapularis - upper and lower subscapular nerve infraspinatus – suprascapular nerve teres minor– axillary nerve medial rotation: subscapularis pectoralis major –medial and lateral pectoral nerve deltoid (anterior part) – axillary nerve latissimus dorsi – thoracodorsal nerve lateral rotation: infraspinatus – suprascapular nerve long head of triceps – radial nerve coracobrachialis – musculocutaneous nerve short head of biceps – musculocutaneous nerve This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Fascia and compartments of the proximal arm Section at a level just short of half-way along the humeris Brachial Fascia - Encloses the upper arm like a sleeve Superiorly, it is continuous with the deltoid fascia, infraspinatus fascia and pectoralis fascia Inferiorly, it is attached to the epicondyles of the humerus and the olecranon of ulna It is continuous with the antebrachial fascia – the fascia of the forearm o It contains two SEPTA: the MEDIAL and LATERAL INTERMUSCULAR SEPTA. o The septa are attached to the supracondylar ridges and to the shaft of humerus o They separate the arm into the ANTERIOR COMPARTMENT and the POSTERIOR COMPARTMENT Anterior compartment Medial intermuscular septum Posterior compartment Lateral intermuscular septum Anterior Compartment: FLEXORS - Biceps Brachii Supplied by the MUSCULOCUTANEOUS - Brachialis - Coracobrachialis NERVE - Median nerve - Musculocutaneous nerve The medial cutaneous nerve of forearm is not inside - the fascial sheath, but is still important enough to warrant a brief mention. The Basilic vein and the Cephalic vein are usually superficial to the fascial planes . Cephalic vein - Triceps Brachii - Anconeus - Radial nerve Supplied by the RADIAL NERVE - Deep artery of the arm (profunda brachii) - Superior ulnar collateral artery - Ulnar nerve as depicted here is in the posterior (A branch of the brachial artery) compartment; it travels anteriorly to the medial intermuscular septum, until it pierces it about half-way down the humerus, together with the superior ulnar collateral artery Radial nerve Lateral intermuscular septum Biceps brachii Lateral intermuscular septum Posterior Compartment: EXTENSORS Deep artery of the arm Musculocutaneous nerve Ulnar nerve Median nerve Triceps brachii Brachialis Medial intermuscular septum Deltoid: Not actually a part of the anterior compartment, as it has its own fascial compartment. Basilic vein Brachial artery Coracobrachialis Medial cutaneous nerve of forearm Medial intermuscular septum Superior ulnar collateral artery This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. The innervation and mechanics of the flexor and extensor muscle compartments of the arm Anterior Compartment: FLEXORS All supplied by the MUSCULOCUTANEOUS NERVE Biceps Brachii Two heads: - SHORT HEAD: o o - Biceps Brachii - Supraglenoid tubercle ligament Brachialis - Transverse humeral ligament LONG HEAD: The lateral head. Originates from the supraglenoid tubercle of the glenoid fossa The biceps inserts into the tuberosity of radius; and it also inserts into the antebrachial fascia by virtue of the bicipital aponeurosis. It does very different things depending on what position the arm is in: o It supinates the forearm by pulling on the aponeurosis, when the arm is pronated; it is the MOST POWERFUL SUPINATOR of the forearm o when the forearm is supine if FLEXES the elbow joint by pulling on the attachment to the radial tuberosity. o It is useless as a flexor when the forearm is pronated. The short head resists dislocation of the shoulder Coracobrachialis - Bicipital aponeurosis Coronoid process and the tuberosity of ulna Tuberosity of radius The medial head. Originates from the tip of the coracoid process o o Coracobrachialis Tip of the coracoid process Some of the brachialis is innervated by the radial nervethe half that is posterior to the insertion of deltoid Short head Long head - Originates at the tip of the coracoid process of scapula Inserts into the middle third of the medial humerus Helps flex and adduct the arm Resists dislocation of the shoulder: it’s a SHUNT muscle, it resists the downward dislocation of the humeral head Stabilizes the glenohumeral goint A landmark – it is pierced by the musculocutaneous nerve Brachialis - Originates from the distal half of the anterior humerus Inserts into the tuberosity of the ulna, and the coronoid process Flexes the forearm in all positions – it’s the PRIMARY FLEXOR Posterior Compartment: EXTENSORS . All supplied by the RADIAL NERVE Triceps Brachii Infraglenoid tubercle - Lateral head of triceps Long head of triceps - LONG HEAD: o Originates from the infraglenoid tubercle LATERAL HEAD: o Originates from the proximal humerus, more proximal than the radial groove MEDIAL HEAD: o Originates from the posterior surface of the humerus, distal to the radial groove The united triceps inserts into the olecranon of ulna Medial head of triceps It is the chief extensor of the arm. The long head resists dislocation of the head of humerus, especially during abduction Anconeus Anconeus - Originates from the posterior lateral epicondyle of humerus Inserts into the lateral surface of olecranon Assists the triceps in flexing the forearm, and stabilizes the elbow joint. It also pulls the joint capsule out of the way of the olecranon upon extension; otherwise it would get pinched in the olecranon fossa . Many anatomists believe it to be a vestigial and forgotten 4th head of the triceps. This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Fascia and compartments of the distal arm Section at the junction of distal third and proximal two thirds of the humerus Biceps brachii Musculocutaneous nerve Coracobrachialis Brachial artery Cephalic vein Lateral cutaneous nerve of forearm which has just branched off Median nerve from the MUSCULOCUTANEOUS nerve Brachialis Posterior cutaneous nerve of forearm which has just branched off Basilic vein from the RADIAL nerve Medial cutaneous nerve of forearm which arises Deep artery of the arm from the MEDIAL CORD of the brachial plexus Radial nerve Lateral head Medial head Ulnar nerve Long head Superior ulnar collateral artery Section at the level of the humeral epicondyles Triceps brachii Basilic vein Cephalic vein Brachial artery Radial nerve which has pierced the lateral intermuscular septum a little while ago, and now travels between brachialis and brachioradialis Median nerve Biceps brachii Brachioradialis Brachialis PRONATOR TERES which is important for a number of reasons: - - Forms the lateral border of the cubital fossa Innervated by the RADIAL NERVE Flexes the forearm, unlike the rest of the forearm extensor compartment Together with the Supinator, they are the only extensor compartment muscles which do not cross the wrist and cause no movement there Ulnar nerve Anconeus Triceps Brachii tendon Which is unimportant, and arguably useless. In fact some anatomists believe it to a rudimentary 4th triceps head. If it were missing, you would likely not notice. This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Fascia and compartments around the cubital fossa and distal forearm Section at the level of the neck of radius Antebrachial Fascia - Median cubital vein Basilic vein Cephalic vein Extension of the brachial fascia Also envelops the forearm like a sleeve There are no “intermuscular” septa per se; the muscles are all invested in their own fascia; however there are still two recogniseable compartments: the FLEXOR compartment and the EXTENSOR compartment. In 20% of people, the basilic vein branches off into a “median basilic” vein, and when it joins the median cephalic vein they form a clear “M”. THERE ARE 17 MUSCLES CROSSING THE ELBOW JOINT. Basilic vein Cephalic vein Median antebrachial vein The BICEPS TENDON: one part blends with the antebrachial fascia; The other part dives deep to attach to the radial tuberosity Highly variable tributaries Brachial artery which bifurcates at the level of the radial head in the cubital fossa Brachialis Brachioradialis Pronator teres which originates proximally to the medial epicondyle, and forms the medial border of the cubital fossa Which forms the lateral border of the cubital fossa The Flexors of the forearm which originate at the Common Flexor origin, at the medial epicondyle of the humerus The branches of the Radial Nerve BrR ECRL, B ED Superficial branch of the radial nerve which travels under brachioradialis down the arm, where it supplies sensation to the dorsum of the hand Deep branch of the Radial Nerve which will pierce the Supinator, penetrate the interosseous membrane and become the Posterior Interosseous Nerve Biceps tendon Radial artery Ulnar artery Daughters of the recently bifurcated Brachial Artery Median nerve which travels between the heads of P. teres Pronator Teres Brachioradialis Flexor Digitorum Superficialis (humeral head) Extensor Carpi Radialis Longus and Brevis Flexor Carpi Radialis Brachialis Palmaris Longus Neck of Radius ULNA Flexor Carpi Ulnaris which is fully innervated by the ulnar nerve, unlike the rest of the flexors Extensor Digitorum Ulnar nerve, which runs between the two heads of flexor carpii ulnaris Annular Ligament Anconeus Flexor Digitorum Profundis Half of which is innervated by the ulnar nerve, unlike the rest of the flexors (which are all supplied by the Median nerve) COMPARTMENTS IN THIS SECTION are not clear-cut or sensible. - - This is an intersection of several compartments. The EXTENSOR compartment of the forearm is anterolateral, represented by brachioradialis, extensor carpi radialis longus and brevis, and extensor digitorum. The FLEXOR compartment is posteromedial and represented by pronator teres, palmaris longus, flexor carpi ulnaris, and flexor digitorum profundus and superficialis. The ANTERIOR compartment of the arm is represented by the biceps tendon, and by brachialis. Anconeus is a lonely representative of the POSTERIOR compartment. This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Fascia and compartments of the middle forearm Section at the level of the mid-forearm Boundaries of the compartments: Lateral border: radial artery Interosseous membrane Medial border: subcutaneous ulna The border between layers 1-2 and layers 3-4 is the primary neurovascular plane of the anterior compartment: the neurovascular bundles exclusive to this compartment travel within it FLEXOR COMPARTMENT Palmaris Longus This is the beefier compartment; twice as fat as the extensor compartment Flexor carpi ulnaris (ulnar nerve) Flexor carpi radialis 4 layers of muscles: Median nerve LAYER 1: pronator teres(not shown, too proximal) Flexor carpi radialis Palmaris longus Flexor carpi ulnaris LAYER 2: Flexor digitorum superficialis Flexor digitorum superficialis Flexor Pollicis Longus LAYER 3:Flexor pollicis longus Flexor digitorum profundis LAYER 4:Pronator Quadratus (not shown, too distal) Flexor digitorum profundus Anterior Interosseous Artery Anterior Interosseous Nerve Half of the Flexor Digitorum Profundus which is innervated by the ulnar nerve, unlike the rest of the flexors (which are all supplied by the Median nerve Ulnar Nerve Ulnar Artery Medial cutaneous nerve of forearm EXTENSOR COMPARTMENT Lateral cutaneous nerve of the forearm Brachioradialis Radial artery Extensor carpi radialis longus Superficial branch of the radial nerve Supinator Extensor pollicis Brevis Abductor pollicis longus Muscles of a similar purpose are grouped together in compartments. The EXTENSORS are posteromedial, and the FLEXORS are anterolateral. They spiral round the arm and eventually the flexors become truly anterior and the extensors become truly posterior. - Functionally, the forearm includes the distal humerus because the muscles that attach at the supracondylar ridges and the epicondyles stretch along the forearm to move the wrist and fingers. BOUNDARIES OF THE COMPARTMENTS Extensor carpi radialis brevis Extensor pollicis Longus Extensor carpi ulnaris POSTERIORLY (proximal forearm) and MEDIALLY (distal forearm), the subcutaneous border of the ulna ANTERIORLY (proximal forearm) and then LATERALLY (distal forearm), Extensor digitorum Posterior interosseous nerve Posterior interosseous artery Extensor indices the radial artery Because neither of these boundaries is crossed by motor nerves they are used for surgical incisions This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. The Flexor Compartment of the Forearm Pronator teres Humeral head Ulnar head is hidden, but it originates from the coronoid process COMMON FLEXOR ORIGIN: Pronator teres, humeral head Flexor carpi radialis Palmaris longus Flexor carpi ulnaris, humeral head Flexor digitorum superficialis, humeral head LAYER 1: All of these, except the ulnar head of pronator quadratus, attach to the medial humeral epicondyle at the COMMON FLEXOR ORIGIN - Flexor carpi Ulnaris Two heads, one originating from the humerus, the other from the olecranon - Inserts into the Pisiform Hook of hamate Base of the 5th metacarpal - Flexor digitorum superficialis Humeroulnar head (common flexor origin and the coronoid process) Radial head PRONATOR TERES Forms the medial border of the cubital fossa; it’s the most lateral of the first layer of muscles Has an ulnar head and a humeral head The humeral head originates from the COMMON FLEXOR ORIGIN The ulnar head originates from the coronoid process Median nerve: mainly Layers 1 and 2 Pronates and flexes the elbow Pronator teres FLEXOR CARPI RADIALIS Flexor carpi radialis o Originates from the COMMON FLEXOR ORIGIN Palmaris longus o Inserts into the base of the 2nd metacarpal Flexor digitorum superficialis o Flexes and abducts the wrist Anterior Interosseous nerve: mainly layer 3 o About half-way down the forearm, its belly is replaced Flexor digitorum profundus, lateral half by a flat tendon which becomes cord-like at the wrist Flexor pollicis longus o It travels in the lateral carpal tunnel inside its own Pronator quadratus synovial sheath (it doesn’t share) Ulnar nerve: o The radial artery is just lateral to this tendon flexor digitorum profundus, medial half flexor carpi ulnaris PALMARIS LONGUS o Originates from the COMMON FLEXOR ORIGIN o Inserts into the distal flexor retinaculum, and palmar aponeurosis. o Flexes and abducts the wrist, tenses the palmar aponeurosis o Its actually absent in 14% of people (usually on the left side). Those people don’t miss it being gone. o The tendon of palmaris longus is a marker for where the median nerve is – the tendon passes medially to it, and then deep to it in the flexor retinaculum o o o o o Palmaris Longus Flexor carpi radialis The belly is replaced by a flat tendon which becomes cord- like at the wrist Median nerve Lateral to the palmaris longus tendon Radial Artery Lateral to the flexor carpi radialis tendon All supplied by the MEDIAN NERVE, …except: The flexor compartment Flexor Digitorum Profundis, ulnar half has 4 discrete layers: Flexor Carpi Ulnaris, whole - FLEXOR CARPI ULNARIS o o o o o Ulnar nerve Has an ulnar and a humeral head Humeral head originates from the COMMON FLEXOR ORIGIN; Ulnar head originates from the olecranon, and posterior border of ulna Inserts into the pisiform, hook of hamate and the 5th metacarpal. Flexes and abducts the wrist; has its own synovial sheath The tendon of flexor carpi ulnaris is a marker for the ulnar artery, which passes laterally to it at the wrist LAYER 2 - FLEXOR DIGITORUM SUPERFICIALIS o o o o Flexor digitorum profundus: Supplied by MEDIAN NERVE ULNAR NERVE Flexor pollicis longus o LAYER 3 - FLEXOR DIGITORUM PROFUNDUS o o o o o o o The flexors digitorum profundus and superficialis are WEAKER when the wrist is flexed, the tendons aren’t tense The fast flexor of the fingers. Has two heads: humeroulnar head and radial head The humeroulnar head originates from BOTH the COMMON FLEXOR ORIGIN and the coronoid process of ulna; the radial head originates the proximal half of the radius It inserts into shafts of the middle phalanges It flexes the metacarpophalangeal joints and the proximal interphalangeal joints; it can flex each joint independently of the others. Its tendons are enclosed in the COMMON FLEXOR SHEATH together with the tendons of flexor digitorum profundus o - The slow flexor of the fingers Originates from the interosseous membrane, and from the proximal three quarters of the anterior surface of the ulna. It has two parts: medial and lateral parts; The medial part is innervated by the ulnar nerve Ulnar nerve The medial part flexes the distal interphalangeal joints of the 4th and 5th digits nd rd The lateral part flexes the distal interphalangeal joints of the 2 and 3 digits All parts can flex the wrist joint as well as the fingers The lateral part is innervated by the ANTERIOR INTEROSSEOUS NERVE (a branch of the median nerve). The tendon to the index finger tends to separate early; it’s the only one which can operate independently. Unlike the flexor digitorum superficialis, the profundus flexes all the DIPs together. FLEXOR POLLICIS LONGUS o o o o Pronator Quadratus Originates from the anterior surface of the radius and the nearby interosseous membrane Inserts into the base of the distal phalanx of thumb. It has its own synovial sheal in the carpal tunnel Also innervated by the ANTERIOR INTEROSSEOUS NERVE It flexes the phalanges of the thumb; mainly the distal interphalangeal joint (it’s the only muscle that flexes the DIP of the thumb) LAYER 4 - PRONATOR QUADRATUS o o o It originates from the distal quarter of the ulna, and inserts into the distal quarter of the radius It is innervated by the ANTERIOR INTEROSSEOUS NERVE It pronates the forearm (it’s the PRIMARY PRONATOR of the forearm) and its fibers hold the radius and ulna together. When speed is needed, it is assisted by the Pronator Teres. This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Extensor Compartment of the Forearm: Superficial layer SUPERFICIAL LAYER OF EXTENSORS All extend the forearm, wrist or fingers two originate from the supracondylar ridge as well as the adjacent – EXCEPT BRACHIORADIALIS Brachioradialis is the solitary exception: it is in the extensor compartment, but it flexes the forearm. It is the only flexor innervated by the radial nerve. All supplied by the RADIAL NERVE, or some branch thereof two layers: the SUPERFICIAL and DEEP intermuscular septum: Brachioradialis o o o o o o Brachioradialis Common extensor origin Extensor Carpi Radialis Longus radial nerve Inserts at the lateral surface of the distal end of the radius Flexes the forearm, in a feeble way, and mostly when the forearm is pronated; it also acts as a shunt muscle to prevent subluxation of the head of radius. its most active in quick movements, and in movement against resistance. Forms the lateral border of the cubital fossa under it run the radial nerve and the radial artery Distally, its tendon is covered by the tendons of Abductor Pollicis Longus and Extensor Pollicis Brevis. Extensor Carpi Radialis Longus o o o o o radial nerve Inserts at the dorsum of the 2nd metacarpal, at the base extends and abducts the hand at the wrist probably more involved in abduction than the ECRB it is crucial in the clenching of the closed fist. Four originate from the common extensor origin, at the lateral epicondyle of the humerus Extensor Carpi Radialis Brevis o o o o o o Extensor Digitorum Extensor Carpi Ulnaris Extensor Digiti Minimi o Extensor Carpi Radialis Brevis which lies under the Extensor Carpi Radialis Longus o o o Extensor Digitorum The fattest muscle here o Tendon sheaths: Extensor carpi ulnaris has its own; and so does extensor digiti minimi. The extensor digitorum shares a sheath with the tendon of Extensor Indicis Brachioradialis tendon which lies under the tendons of Abductor Pollicis Longus and Extensor Pollicis Brevis o o o posterior interosseous nerve which is really the continuation of the deep branch of the radial nerve inserts at the extensor expansions of the fingers THE EXTENSOR EXPANSIONS are triangular aponeuroses which wrap around the metacarpal head, and the proximal phalanx. They are united with the insertions of the lumbricals and the interosseous muscles. The tendons thus divide into a median band which passes to the base of the middle phalanx, and two lateral bands which insert at the base of the distal phalanx. Extends the fingers, primarily at the metacarpophalangeal joint; secondarily at the distal interphalangeal joint. Occupies a lot of space in the extensor compartment Shares an extensor tendon sheath with the Extensor Indicis Just proximally to the metacarpophalangeal joints, the tendons are linked by intertendinous connections which prevent the fingers from being independently extended; thus you can never fully extend a finger while the others remain flexed. This is most true of the ring finger. Extensor Digiti Minimi The common tendon sheath of th extensors carpi radialis: both travel within the same sheath o o o o o The Tendon of Extensor Digit Minimi divides into two tendons; the lateral one joins the extensor digitorum tendon to the little finger deep branch of radial nerve Inserts into the dorsum of the 3rd metacarpal at the base extends and abducts the hand at the wrist it is covered by the Extensor Carpi Radialis Longus They also share the same extensor tendon sheath at the wrist the brevis is more involved in extension than the longus The Insertions of the Extensors Carpi Radialis tendons: Bases of the metacarpals Longus inserts into the 2nd Brevis inserts into the 3rd Intertendinous connections which unite the extensor digitorum tendons and prevent the digits from extending independently posterior interosseous nerve Divides into two tendons- the lateral one joins the pinky tendon of the extensor digitorum, and then together with the medial one all three insert into the extensor expansion of the pinky finger. extends the pinky, primarily at the metacarpophalangeal joint; secondarily at the distal interphalangeal joint. this is really just a detached part of the extensor digitorum However, it has its own tendon sheath Extensor Carpi Ulnaris o o o o o o posterior interosseous nerve yes it does originate at the common extensor origin; thats the humeral head. There is also an ulnar head, which originates at the ulnar border posteriorly, via an aponeurosis. This origin is also shared with the Flexor Digitorum profundis and the Flexor Carpi Ulnaris. inserts at the dorsum of the base of 5th metacarpal extends the hand at the wrist joint, and abducts it It has its own tendinous sheath at the wrist It is also crucial to the formation of the closed fist This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Extensor Compartment of the Forearm: Deep layer DEEP LAYER OF EXTENSORS "true" deep layer Supinator o o Supinator Attachments of the Supinator to the Epicondyle of humerus Radial collateral ligament Annular ligament of radius Ulnar Supinator crest and fossa Ulnar posterior surface Interosseous membrane o o o Extensor Indicis o o Abductor pollicis longus o o o the Supinator wraps around the radius to insert into the anterior surface of it. Together with the brachialis it forms the floor of the cubital fossa Extensor Pollicis Longus these originate from the proximal, middle and distal thirds of the ulna (as a generalization). They emerge in the surface in the furrow that forms in the extensor compartment Abductor Pollicis Longus o o Extensor Indices Which shares an extensor tendon sheath with the Extensor Digitorum tendon Posterior interosseous nerve originates from the posterior surface of the distal third of the ulna, and the interosseous membrane inserts into the extensor expansion of the index finger extends the index finger, enabling independent extension helps extend the hand at the wrist "outcropping" deep layer o o Extensor Pollicis Brevis deep branch of radial nerve which pierces it on its way to transforming into the posterior interosseous nerve originates from everywhere... the lateral humeral epicondyle, the radial collateral ligament, the annular ligament, the supinator fossa and the crest of ulna inserts into the lateral posterior and anterior surfaces of the proximal third of radius it supinates the forearm, turning the arm to face anteriorly and superiorly when the forearm is flexed. It is the PRIME MOVER for slow unopposed suination The supinator forms the floor of the cubital fossa together with brachialis. It is a sheet-like muscle, and it envelops the radius. o Posterior interosseous nerve originates from the posterior surface of the proximal radius and ulna, as well as the interosseous membrane inserts into the base of the 1st metacarpal, and occasionally also the trapezium. abducts and extends the thumb at the carpometacarpal joint shares a common tendon sheath with the extensor pollicis brevis at the wrist Extensor Pollicis Brevis Common sheath for the tendons of the extensor pollicis brevis and abductor pollicis longus o o o o o o o Posterior interosseous nerve originates from the posterior surface of the distal third of the ulna, and the interosseous membrane inserts into the dorsum of the base of the proximal phalanx of the thumb extends the proximal phalanx of the thumb at the metacarpophalangeal joint; also extends the carpometacarpal joints of the thumb. partly covered by the abductor pollicis longus its tendon is immediately medial to the APL these two tendons form the anterior boundary of the anatomical snuffbox. Extensor Pollicis Longus o o o Extensor digitorum tendon o Extensor expansion Medial band attaches to the base of the middle phalanx o o Lateral bands attach to the base of the distal phalanx The hood which attaches to the palmar tendon Posterior interosseous nerve originates from the posterior surface of the middle third of the ulna, and the interosseous membrane inserts into the dorsum of the base of the distal phalanx of the thumb extends the distal phalanx of the thumb; also extends the metacarpophalangeal and the carpometacarpal joints of the thumb. It also rotates the thumb laterally. It enjoys its own tendon sheath at the wrist; it passes medially over the dorsal tubercle of radius, using it as a pulley. the EPL forms the posterior border of the anatomical snuffbox APL inserts into the base of 1st metacarpal EPB inserts into the base of proximal phalanx EPL inserts into the base of distal phalanx This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Flexor and Extensor Tendons at the Wrist: level of the Distal Radioulnar Joint Flexor Digitorum Superficialis Flexor Digitorum Profundus Palmaris Longus Ready to merge with the palmar aponeurosis Flexor Pollicis Longus Median Nerve Ulnar Artery Flexor Carpi Radialis Ulnar nerve Radial Artery Flexor Carpi Ulnaris can cover the ulnar artery and obscure its pulsation Abductor Pollicis Longus ULNA Extensor Pollicis Brevis RADIUS Extensor Carpi Ulnaris Extensor Digiti Minimi Extensor Carpi Radialis Longus Extensor Digitorum Extensor Indices Extensor Carpi Radialis Brevis Extensor Pollicis Longus The Extensor Retinaculum -- attaches Attaches to the lateral border of the radius - Does NOT attach to the border of the ulna, because the ulna moves too much. Instead, attaches to the pisiform and the triquetrum Also attaches to the ridges of the radius, thus forming osseofibrous tunnels for the above tendons to run through There are 6 tunnels in total: 1. One for abductor pollicis longus and extensor pollicis brevis 2. One for extensor carpi radialis longus and extensor carpi radialis brevis 3. One for extensor pollicis longus 4. One for extensor digitorum and extensor indices 5. One for extensor digiti minimi 6. One for extensor carpi ulnaris This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. The Carpal Tunnel and its Contents This is a narrow enclosed space. Needless to say, if anything in here swells, the median nerve will get compressed. It is the most sensitive structure in the carpal tunnel. The lateral three and a half digits will get diminished sensation Sensation on the thenar eminence will be spared because the palmar cutaneous branch splits from the median nerve long before the flexor retinaculum The movement of the thenar muscles is controlled by a terminal motor branch of the median nerve, and so the thenar muscles will atrophy in carpal tunnel syndrome Ulnar Artery Palmaris Longus Ulnar Nerve Hypothenar muscles Thenar muscles TRAPEZIUM Abductor Pollicis Longus Extensor Pollicis Brevis HAMATE Extensor Pollicis Longus TRAPEZOID Extensor Carpi Ulnaris CAPITATE Radial Artery Crossing over to the dorsum of the hand Extensor Digiti minimi Extensor Carpi Radialis Longus Extensor Carpi Radialis Brevis Extensor Indices Extensor Digitorum Tuberosity of Trapezium Hook of Hamate Flexor retinaculum Median Nerve Tuberosity of Scaphoid Flexor Carpi Radialis Flexor Digitorum Superficialis Pisiform Flexor Pollicis Longus Flexor Digitorum Profundus The Flexor retinaculum is stretched between four bony posts: 1) Hook of hamate 2) Pisiform bone 3) Tuberosity of scaphoid 4) Tuberosity of trapezium This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. A Summary of the Innervation of the Extensors and Flexors of the Forearm Flexors Extensors All innervated by branches of the RADIAL NERVE Radial nerve itself: innervates muscles with attachments proximal to the cubital fossa - Brachioradialis - Extensor Carpi Radialis Longus - Both of these originate at the supracondylar ridge Deep branch of the radial nerve: a branch which splits off from the radial nerve at the level of the humeral condyle in the cubital fossa; it pierces the supinator muscle, and becomes the posterior interosseous nerve - Extensor Carpi Radialis Brevis - Supinator Posterior interosseous nerve: travels along the posterior aspect of the interosseous membrane; innervates most of the extensor muscles - Extensor digitorum Extensor Indicis Extensor Digiti minimi Extensor Carpi Ulnaris Extensor Pollicis Longus Extensor Pollicis Brevis Abductor Pollicis Longus Innervated by either the ULNAR or the MEDIAN nerves Median nerve itself: - Pronator Teres - Palmaris Longus - Flexor carpi Radialis - Flexor Digitorum Superficialis Anterior interosseous nerve, a branch of the median nerve: - Flexor Digitorum Profundus - lateral half - Flexor Pollicis Longus - Pronator Quadratus Ulnar nerve: - Flexor Digitorum profundus, only the medial half - Flexor Carpi Ulnaris Ulnar nerve : Innervates the muscles directly adjacent to it along its course down the arm Radial nerve is in red Deep branch of the radial nerve is in pink Median nerve: Innervates mainly the 1st and 2nd layer of flexors Anterior Inerosseous nerve: innervates the 3 deepest muscles Posterior interosseous nerve is in green This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Fascia, Septa, Tendon Sheaths and the Potential Spaces of the Hand These fascial layers are continuous with the fascial sleeve of the forearm. Centrally the fascia of the palm thickens in the centre, where the palmaris longs tendon attaches to it, which is also where it merges with the flexor retinaculum. This whole thickened area is called the palmar aponeurosis. Distally, the palmar aponeurosis divides into four bands which attach to the bases of the proximal phalanges, and there it becomes a part of the digital sheaths All merge into the Palmar Aponeurosis Palmaris Longus tendon Antebrachial Fascia Flexor retinaculum The Thenar Space Palmar Aponeurosis so thick and tough that any infections in the palmar spaces will actually cause the weaker DORSAL fascia to bulge out. In Dupuytren’s contracture, the palmar aponeurosis becomes nodular, fibrosed, and thickened Thenar fascia The Midpalmar Space Palmar Aponeurosis Hypothenar fascia Lateral fibrous septum of the palm which stretches from the palmar aponeurosis to the 3rd metacarpal Medial fibrous septum of the palm which stretches from the palmar aponeurosis to the 5th metacarpal Unlike the thenar space, this one is continuous with the anterior compartment of the forearm- it communicates with it via the carpal tunnel. Digital Synovial Sheaths Of the two septa, the LATERAL is the strongest The common flexor sheath continues to the 5th digit. The other digits have their own Digital Synovial Sheaths Synovial sheath for Flexor Pollicis Longus Common flexor sheath: FDS and FDP Synovial sheath for Flexor Carpi Radialis This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Compartments of the palm and their contents Thenar compartment Contains the thenar muscles Adductor compartment Contains only Adductor Pollicis Central compartment Contains the flexor tendons and their sheaths, the lumbricals, the superficial arterial palmar arch, and the digital vessels and nerves Hypothenar compartment Contains the hypothenar muscles Interosseous compartments Contains the interossei muscles Thenar Compartment Flexor Pollicis Brevis: Superficial head which is innervated by the MEDIAN NERVE Central Compartment Deep Head which is innervated by the DEEP BRANCH OF THE ULNAR NERVE 1st and 2nd Lumbricals which are unipennate and which are innervated by the MEDIAN NERVE 3rd and 4th Lumbricals which are bipennate and which are innervated by the DEEP BRANCH OF THE ULNAR NERVE Abductor Pollicis Brevis Abductor Digiti Minimi Opponens Pollicis Hypothenar Compartment Adductor Pollicis Opponens Digiti Minimi Adductor compartment Flexor Digiti Minimi Brevis 1st Dorsal Interoissei 3rd Palmar Interoissei 1st Palmar Interoissei Interosseous compartment 2nd Dorsal Interoissei 2nd Palmar Interoissei rd 3 Dorsal Interoissei 4th Dorsal Interoissei This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Thenar and Hypothenar muscles There are 3 Thenar muscles, 3 Hypothenar muscles, 1 Adductor muscle, 4 Lumbricals, 4 dorsal interossei and 3 palmar interossei ADDUCTOR POLLICIS, which has 2 heads, between the origins of which the RADIAL ARTERY emerges to form the deep palmar arch Transverse head of Adductor Pollicics, which originates from the 3rd metacarpal Oblique head of Adductor Pollicics, which originates from the 3rd metacarpal as well as from the 2nd metacarpal, the capitate bone, and all adjacent carpal bones Opponens Digiti Minimi Which originates from the flexor retinaculum and the hook of hamate, and inserts into the medial border of the 5th metacarpal Adductor pollicis inserts into the lateral part of the 1st proximal phalanx Flexor pollicis brevis with two heads: the superficial and the deep. The deep head is innervated by the deep branch of the ulnar nerve Flexor Digiti Minimi Brevis Which originates from the flexor retinaculum and the hook of hamate, and inserts into the medial side of the base of the 5th proximal phalanx Abductor Digiti Minimi Which originates at the pisiform and inserts into the medial side of the base of base of 5th proximal phalanx Abductor Pollicis Brevis Both of these muscles originate from the flexor retinaculum and the tubercles of scaphoid and trapezium; they both insert into the lateral aspect of the base of the proximal phalanx of the thumb. Flexor retinaculum Opponens Pollicis Also originates from the flexor retinaculum and the tubercles of scaphoid and trapezium; however it inserts into the lateral border of the 1st metacarpal. Hypothenar Muscles In the HYPOTHENAR compartment Opponens Digiti Minimi o o o o o deep branch of ULNAR NERVE originates from hook of hamate and the flexor retinaculum inserts into the medial border of the 5th metacarpal pulls the 5th metacarpal anteriorly, and rotates the 5th digit so it can participate in opposition with the thumb acts exclusively at the MCP joint Flexor Digiti Minimi Brevis o o o o deep branch of ULNAR NERVE originates from hook of hamate and the flexor retinaculum inserts into the medial side of the base of the 5th proximal phalanx flexes the proximal phalanx of the 5th digit Abductor digiti Minimi o o o o o deep branch of ULNAR NERVE originates from the pisiform inserts into the medial surface of the bae of the 5th proximal phalanx Abducts the 5th digit and assists in its flexion It is the most superficial of the three hypothenar muscles Thenar Muscles In the ADDUCTOR compartment Both ofPollicis these muscles originate from the flexor retinaculum Adductor - and the tubercles of scaphoid and trapezium; they both insert o deep branch of the Ulnar nerve into the lateral aspect of the base of the proximal phalanx of the TRANSVERSE HEAD originates from the anterior surface of the 3rd thumb. metacarpal OBLIQUE HEAD originates from the bases of the 2nd and 3rd metacarpals, from the capitate bone, and from any carpals around the capitate. Inserts into the medial side of the base of proximal phalanx of thumb. There tends to be a sesamoid bone at the site of insertion. Adducts the thumb towards the lateral border of the palm (presses it against the palm) In the THENAR compartment Flexor Pollicis Brevis o o o o o DEEP HEAD: deep branch of ULNAR NERVE SUPERFICIAL HEAD: Recurrent branch of MEDIAN NERVE originates from the flexor retinaculum and the tubercles of the scaphoid and trapezium. Inserts into the lateral aspect of the base of the proximal phalanx of the thumb Flexes the thumb: brings its tip towards the base of pinky Abductor Pollicis Brevis: Recurrent branch of MEDIAN NERVE There is also Palmaris Brevis; a useless little muscle which wrinkles the skin of the palm; it originates at the flexor retinaculum and inserts into the skin. The ulnar nerve innervates it. IT IS NOT PART OF THE HYPOTHENAR COMPARTMENT o o o originates from the flexor retinaculum and the tubercles of the scaphoid and trapezium. Inserts into the lateral aspect of the base of the proximal phalanx of the thumb Abducts and helps oppose the thumb Opponens Pollicis Brevis: Recurrent b. of MEDIAN NERVE o o originates from the flexor retinaculum and the tubercles of the scaphoid and trapezium; Inserts into the lateral side of the 1st metacarpal. Opposes the thumb: medially rotates and the pulls medially the 1st metacarpal. Acts exclusively at the MCP joint This document was created by Alex Yartsev ([email protected]); if I have used your data or images and forgot to reference you, please email me. Short muscles of the Hand o there are 4 lumbricals, 4 dorsal interossei, and 3 palmar interossei; you count them starting at the THUMB The LUMBRICALS - Originate from the tendons of the FLEXOR DIGITORUM PROFUNDIS Sit in the central compartment of the palm From the palm, cross over to the dorsum of the hand Insert into the extensor expansions on the dorsum of the proximal phalanges The FIRST and SECOND lumbricals are innervated by the median nerve. All other short muscles are innervated by the deep branch of the ulnar nerve The THIRD and FOURTH lumbricals are bipennate; the other two are unipennate FLEX the metacarpophalangeal joints EXTEND the proximal interphalangeal joints Together the short muscles all produce the “Z” movement of the fingers; the MCPs are flexed, and the PIPs extended. This is the opposite of what happens in ulnar nerve palsy (“claw hand”) when the MCPs are extended and the PIPs are flexed. The DORSAL INTEROSSEI - Originate from the sides of two metacarpals (ALL of them are bipennate) Sit in their own INTEROSSEOUS compartment of the hand Insert into the bases of the proximal phalanges and into the extensor expansions ABDUCT the hand away from the axis of the middle finger (the axis as shown)- hence “DAB” (“ Dorsal Interosei ABduct”) Also help the lumbricals flex the MCPs and extend the PIPs When the thumb is flexed, the first dorsal interossei can be seen as the lump that appears on the dorsum of the hand. The Interossei all live inside the INTEROSSEOUS compartment. The Palmar interossei occupy the anterior (palmar )part of it, and the dorsal interossei are more properly between the metacarpals. The PALMAR INTEROSSEI - Originate from the palmar surfaces of the metacarpals Sit in the anterior part of the INTEROSSEOUS compartment of the hand Inset into the bases of the proximal phalanxes and into the extensor expansions ADDUCT the fingers towards the middle finger, hence “PAD”- Palmar Interossei Adduct There are only 3 palmar interossei; the deep part of the Flexor Pollicis Brevis can be described as the 4th, because it does much the same thing as the rest, and is innervated by the same nerve References: Moore’s Clinically Oriented Anatomy 5th edition