Skin of the back and scapular region Sensory

Skin of the back and scapular region : ØSensory nerve supply of skin : post. Rami of spinal N. 1 -skin of the neck : by post. Rami of cervical Ns. C 2 -C 7 except C 1 and C 8 spinal Ns. 2 -skin of back of chest : by post. rami of upper 6 thoracic Ns. 3 -skin of back of (loin) abdomen : by lower 6 thoracic Ns. 4 -skin of buttock (gluteal): by upper 3 lumbar Ns. ØBlood Supply : post branches of post. Intercostal & lumbar arteries. Veins drain into azygos veins & I. V. C. ØLymph drainage : above iliac crest into post. axillary L. Ns.

Muscles of the back and scapular regions

Rotator Cuff Ø 4 muscles : supraspinatus , infraspinatus, teres minor & subscapularis. ØThey assist in holding head of humerus in glenoid cavity of scapula during movements of shoulder joint, so, they assist in stabilizing shoulder joint. ØThe cuff lies on the anterior, posterior & superior aspects of shoulder joint. ØIt is deficient inferiorly, so it is the site of weakness

Quadrangular space ØIt is an intermuscular space , bounded above by subscapularis & capsule of shoulder j. and inferiorly by teres major, medially by long head of triceps , laterally by surgical neck of humerus. ØAxillary N. + post. Circumflex humeral vessels pass backward through this space.

Spinal root of accessory nerve : ØIt runs downward in the post. triangle of neck on the levator scapulae. ØIt is accompanied by 3 rd & 4 th cervical nerves + transverse (superficial ) cervical artery. ØIt passes deep to trapezius to supply it. ØIt can be injured in case of stab wounds in the neck.

Suprascapular nerve ØIt arises from upper trunk of brachial plexus(C 5+C 6) in the post. Triangle of neck. ØIt runs downward deep to suprascapular ligament, which bridges suprascapular notch, to reach supraspinous fossa. ØIt supplies supraspinatus & infraspinatus & shoulder joint.

Axillary Nerve : ØIt arises from post. cord of brachial plexus(C 5 & C 6) in the axilla. ØIt passes backward through quadrangular space, inferior to capsule of shoulder joint and medial to surgical neck of humerus, accompanied with post. Circumflex humeral artery. ØBranches : 1 -articular branch to shoulder joint. 2 -anterior terminal branch : it winds around surgical neck of humerus deep to deltoid to supply it & skin over lower ½ of deltoid. 3 -post. terminal branch : it gives branches to teres minor + deltoidthen turns around post. border of deltoid as upper lateral cutaneous N. of arm to supply skin over lower ½ of deltoid muscle.

Sterno-clavicular joint : ØArticular surfaces : between sternal end of clavicle, manubrium sterni, and 1 st costal cartilage. ØType : plane synovial joint. ØCapsule : is attached to margin of articular surfaces. ØLigaments : 1 -anterior & post. sternoclavicular ligaments to reinforce the capsule in front & behind joint. 2 -Accessory ligament (costoclavicular ligament) : connects inferior surface of medial(sternal) end of clavicle to the junction of 1 st rib & its costal cartilage. ØArticular disc : it is fibrocartilaginous disc, which divides joint cavity into 2 cavities. ØSynovial membrane : lines the capsule inside the joint.

Sterno-clavicular joint : ØNerve supply : supraclavicular + nerve to subclavius. ØMovements : 1 -forward & backward movement of clavicle takes place in medial compartement. 2 -elevation & depression of clavicle takes place in lateral compartement ØForward movement of clavicle : by serratus anterior. ØBackward movement of clavicle : by trapezius & rhomboids. ØElevation of clavicle : by trapezius, sterno-cleidomastoid, levator scapulae & rhomboids. ØDepression of clavicle : by pectoralis minor & subclavius.

Acromio-clavicular joint ØArticulation : between acromion & lateral end of clavicle. ØType : plane synovial j. ØCapsule : surrounds j. and is attached to the articular surfaces. ØLigaments : 1 -sup. & inf. acromio-clavicular ligaments : reinforce the capsule. 2 -accessory ligament (coracoclavicular lig. ) : from coracoid process to undersurface of clavicle. ØArticular disc : a wedge-shaped fibrocartilaginous disc projects into joint cavity from above.

Acromio-clavicular joint ØSynovial membrane : lines capsule. ØNerve supply : supra-scapular N. ØMovements : a gliding movement takes place when scapula rotates or when clavicle is elevated or depressed. ØRelations; -anterior : deltoid -posterior : trapezius. -superiorly : skin

Muscles of Shoulder Region • Deltoid. • Supraspinatus. • Infraspinatus. • Subscapularis. • Teres minor. • Teres major. N. B : Supraspinatus, infraspinatus, teres minor and Subscapularis--- these are Rotator cuff muscles, playing an important role in keeping the head od humerus in contact with the glenoid cavity during movements of shoulder joint.

Shoulder joint ØArticulation : 1 -head of humerus. 2 -glenoid cavity of scapula, which is deepened by fibrocartilaginous rim called the glenoid labrum (intra-capsular). ØType : ball & socket synovial j ØCapsule : it surrounds joint –medially : it is attached to margin of glenoid cavity outside the labrum. Anterior view Ø-laterally : it is attached to anatomical neck of humerus +transverse humeral ligament.

Shoulder joint ØCapsule : -It is thin & lax specially inferiorly, thus allowing a wide range of mobility. -It is strengthened by ligaments & tendons of rotator cuff muscles : (supra-spinatus, infraspinatus, teres minor & subscapularis). Sagittal section v. Long head of biceps is intracapsular. v. Long head of triceps supports the capsule during abduction of arm.

Shoulder joint openings in the capsule: 1 -an opening in anteromedial part, the synovial membrane passes through this opening to form subcapsularis bursae beneath subscapularis, and separates subscapularis from front of capsule. Anterior view 2 -an opening deep to transverse ligament of humerus at upper end of bicipital groove, it transmits tendon of biceps, surrounded by a synovial tube.

Ligaments of Shoulder joint ØIntra-capsular Ligaments 1 -Glenohumeral ligaments : are 3 bands of fibrous tissue that strengthen the front of capsule. 2 - Transverse humeral ligament : strengthens the capsule and bridges the groove between the 2 tuberosities- tendon of long head of biceps passes beneath the ligament Extrapsular ligament : 3 - Coraco-humeral ligament : strengthens the capsule above and extends from root of coracoid process to greater tuberosity of humerus. ØAccessory ligaments : 4 -Coraco-acromial ligament : extends between coracoid process & acromion of scapula.

Shoulder joint Interior of joint Sagittal section Synovial membrane : -lines the capsule interiorly. -it is attached to margins of hyaline cartilage covering the articular surfaces. -it forms a tubular sheath around tendon of long head of biceps. -it passes through opening in the capsule to form subscapularis bursa (between capsule & subscapularis). Nerve supply : axillary N. & supra-scapular nerve(C 5, 6).

Shoulder joint Relations : ØAnteriorly : subscapularis , axillary vessels & brachial plexus. ØPosteriorly : infraspinatus & teres minor. ØSuperiorly : Supraspinatus, subacromial bursa, coraco-acromial ligament & deltoid mus. Sagittal section ØInferiorly : long head of triceps, axillary N. & post. circumflex humeral ves. ØTendon of long head of biceps passes through the joint and emerges beneath the transverse lig.

Movements of shoulder joint ØFlexion : carries arm forwards & medially, it is performed by : -Anterior Fs. of deltoid. -Pectoralis major (clavicular head) -Biceps (short head) & Coracobrachialis. ØExtension : carries arm backwards, it is performed by: -Posterior Fs. of deltoid. --Teres major. -Latissimus dorsi. ØAbduction : movement of arm laterally & upwards, it occurs in 3 stages : -1 st stage from 0 -15, by supraspinatus, it initiate movement of abduction.

Movements of shoulder joint -2 nd stage : from 15 -90, occurs by middle Fs. Of deltoid. -3 rd stage : more than 90, occurs by combined action of Serratus anterior & Trapezius. ØAdduction : by -Pectoralis major. -Teres major. -latissimus dorsi. -helped by subscapularis & Teres minor. ØMedial rotation : -Anterior Fs. Of deltoid. -pectoralis major. –Teres major –latissimus dorsi. -Subscapularis ØLateral rotation : by -Posterior Fs. Of deltoid. -Infraspinatus. -Teres minor.

Movements of shoulder joint (S) 0 -15 ØCircumduction : is a combination of flexion, abduction, extension & adduction ØScapula & upper limb are suspended from clavicle by strong coraco-clavicular lig. (D)Middle fibers 15 -90 (T+SA) Above 90 ØIn abduction above head, greater tuberosity of humerus comes in contact with acromion of scapula.

Arterial Anastomosis around Scapula & Shoulder ØIt occurs between the branches of 1 st part of subclavian & 3 rd part of axillary artery. ØIt occurs on the bone at inferior angle of scapula, in subscapular, supraspinous & infraspinous fossae. ØBranches from 1 st part of subclavian artery : 1 -Suprascapular artery : lies above suprascapular ligament, is distributed to supraspinous & infraspinous fossae. 2 -Deep branch of superficial cervical artery : It runs down on medial border of scapula into inferior angle of scapula.

Arterial anastomosis around the scapula & shoulder ØBranches from 3 rd part of axillary artery : 1 -Subscapular artery: -It descends along lower border of subscapularis (into inferior angle & subscapular fossa). -It gives circumflex scapular artery. 2 -Circumflex scapular artery: it pass deep to teres minor to pass into infraspinous fossa. Ø Both anterior & posterior circumflex humeral arteries form anastomosing circle around surgical neck of humerus to supply shoulder joint.

The Cubital Fossa ØIt is a triangular depression that lies in front of ellbow. ØBoundaries : -base : imaginary line between 2 epicondyles of humerus –apex : overlapping of brachioradialis to pronator teres. -laterally : brachioradialis -medially : pronator teres. –floor : supinator. & brachialis. -Roof : skin, fascia, & bicipital aponeurosis. ØContents : from medial to lateral: 1 -median N. 2 -bifurcation of brachial artery into ulnar & radial arteries. 3 -tendon of biceps. 4 -radial N. & its deep branch. 5 -supratrochlear Lymph Node.

The Cubital Fossa ØBrachial artery terminates into radial & ulnar arteries at the neck of radius. ØRadial artery leaves fossa by passing undercover of brachioradialis. ØUlnar artery leaves fossa by passing deep to pronator teres. ØMedian nerve leaves fossa by passing between 2 heads of pronator teres.

Supratrochlear lymph node ØIt lies in superficial fascia over upper part of fossa, above trochlea. ØIt recevies afferent lymph vessels from : 1 -3 rd , 4 th & 5 th fingers. 2 -medial part of hand. 3 -medial side of forearm. ØIts efferent lymph vessels accompany basilic vein to end in lateral group of axillary L. Ns.

Cutaneous nerves of forearm ØLateral cutaneous nerve of forearm : -it is the continuation of musculocutaneous nerve –it gives anterior & posterior branches. ØMedial cutaneous nerve of forearm : -it is a branch of medial cord of brachial plexus. -it gives anterior & posterior branches to supply medial ½ of front of forearm & medial side of forearm respectively. ØPosterior cutaneous nerve of forearm : -it is a branch of radial N. -it supplies skin of back of forearm.

Superficial veins ØCephalic vein : -arises from lateral side of dorsal venous arch on the back of hand. -it ascends on lateral side of forearm into the front of cubital fossa. -In the cubital fossa, it gives median cubital vein to join the basilic vein. ØBasilic vein : -arises from medial side of dorsal venous arch on back of hand. -it ascends on medial side of forearm. -In front of cubital fossa, it recevies median cubital vein.

Fascial compartments of forearm & interosseous membrane ØThe forearm is enclosed in a sheath of deep fascia, which is attached to the periosteum of posterior border of ulna. ØFascial sheath together with I. M. + fibrous intermuscular septa, divides forearm into anterior, lateral & posterior compartments. ØInterosseous membrane (I. M) : is a thin strong membrane uniting radius & ulna between their interosseous borders, its Fs. run obliquely downward & medially. Its lower part is pierced by anterior interosseous vessels. ØOblique cord : is a fibrous cord that extends from the radius (below tuberosity) to apex of coronoid process of ulna.

T. S in Forearm to show anterioer & posterior compartments

Contents of front of forearm ØSuperficial muscles (lateral to media) Anterior Fascial compartment 1 -pronator teres. 2 -flexor carpi radialis. 3 of forearm : palmaris longus. 4 flexor digitorum superficialis 5 -flexor carpi ulnaris. ØDeep muscles: 1 flexor digitorum profundus. medially 2 -flexor pollicis longus. laterally 3 -pronator Quadratus. ØMedian N. : supplies all Ms. except flexor carpi ulnaris & medial ½ of flexor digitorum profundus. ØUlnar N. : supplies flexor carpi ulnaris & medial ½ of flexor digitorum profundus. ØSuperficial branch of radial N--has no branches in forearm. ØRadial & ulnar arteries.

Deep group of muscles of Forearm ØFlexor digitorum profundus…medially ØFlexor pollicis longus…laterally. ØPronator quadratus.

Median Nerve in forearm ØIt leaves cubital fossa to enter forearm between 2 heads of pronator teres. ØIn the forearm, it descends in the middle, between flexor digitorum superficialis , & flexor digitorum profundus. ØAt the wrist, it enters hand by passing deep to flexor retinaculum. ØBranches in forearm : -muscular : pronator teres, + flexor carpi radialis, +palmaris longus + flexor digitorum superficialis. -articular : elbow, sup. radio-ulnar, wrist joints. -anterior interosseous nerve : it descends in front of interosseous membrane.

Median Nerve ØBranches of anterior interoseous nerve : -muscular : flexor pollicis longus _ lateral ½ of flexor digit. profundus + pronator Q. -articular : inferior radio-ulnar joint + wrist joint. -palmar cutaneous nerve : arises above wrist j. , to pierce deep fascia to descend superficial to flexor retinaculum to supply skin of lateral 2/3 of palm.

Cutaneous nerves of palm & fingers (supplies base of thenar eminence)

Ulnar Nerve ØAt the elbow : it passes behind medial epicondyle to enter forearm by passing between 2 heads of flexor carpi ulnaris. ØIn the forearm, it descends in the medial side, medial to ulnar artery, deep to flexor carpi ulnaris, superficial to flexor digit. profundus. ØAbove wrist, it pierces deep fascia to descend superficial to flexor retinaculum and lateral to pisiform bone, between tendon of F. C. U. & F. D. S. ØBranches : -muscular : flexor carpi ulnaris + medial ½ of F. D. P. -articular : to elbow joint. -palmar cutaneous : pierces deep fascia to supply skin over hypothenar eminence + skin of medial 1/3 of palm. -posterior cutaneous branch : passes posteriorly to supply skin of back of medial 1/3 of hand + skin of back of proximal phalanx of medial 1 ½ fingers, ( by 2 dorsal digital nerves).

Radial Nerve Ø It pierces lateral intermuscular septum of lower arm to pass into cubital fossa. ØIt then passes in front of lateral epicondyle , between brachialis(medially) and / brachioradialis & ext. carpi radialis longus. At level of lateral epicondyle, it divides into superfical & deep branches. ØBranches : -muscular : lateral part of brachialis + brachioradialis + ext. C. R. longus. -articular : elbow joint. -deep branch of radial N. (posterior interoseous N. ) : arises from radial N. in cubital fossa in front of lateral epicondyle. It pierces supinator muscle to wind around neck of radius and reach posterior compartment of forearm between superficial & deep muscles to supply the extensor muscles. -Superficial branch : it is direct continuation of radial N. , descending deep to brachioradialis. Above wrist, it pierces deep fascia and turns backwards to supply skin of lateral 2/3 of back of hand + skin of back of proximal phalanges of lateral 3 1/2 fingers.

Ulnar artery ØIt begins in cubital fossa at level of neck of radius as the largest terminal branch of brachial artery. ØIn upper part, it lies deep to flexors of forearm. ØBelow it becomes superficial , lies between tendons of F. C. U. & F. D. S. to pass in front of flexor retinaculum, lateral to pisiform bone (site for ulnar pulse) ØBranches : -muscular. -Recurrent branches: anterior & posterior ulnar recurrent to take part in anastomosis around elbow. -Common interosseous : divides into anterior & posterior , lying in front & behind interosseous membrane and provide nutrient arteries to radius & ulna.

Branches of ulnar artery in forearm : ØMuscular. ØRecurrent branches that take part in anastomosis around elbow. ØBranches that take part in anastomosis around wrist. ØCommon interosseous artery : arises from upper part of ulnar artery and after a short course divides into anterior & posterior interosseous arteries in front & behind I. M. , they are nutrient to radius & ulna.

Radial artery ØIt is the smaller terminal branch of brachial artery , begins in cubital fossa, at level of neck of radius. ØIt passes laterally, in front of forearm deep to brachioradialis. ØIts distal part is superficial, covered by skin, superficial fascia & deep fascia. (site of radial pulse on lateral end of radius close to lateral side of tendon of flexor carpi radialis). ØAt wrist, it turns backwards to posterior surface of hand. ØBranches : -muscular -Radial recurrent artery : takes part in anastomosis around elbow. -Superficial palmar branch : arises just above wrist, enters palm of hand to join ulnar artery to form superficial palmar arch.

Flexor Retinaculum (Anterior carpal tunnel) vit is a thickening of deep fascia that holds long flexor tendons in position in front of the wrist. v. The bones of hand & flexor retinaculum form osteofascial tunnel, (carpal tunnel), for passage of median N. & flexor tendons of thumb & fingers. v. Median N. lies in restricted space between tendons of F. D. S & F. C. R. Cross section of the hand v. It is attached medially to pisiform bone & hook of hamate, and laterally to tubercle of scaphoid & trapezium (in which the attachment consists of superficial & deep parts to form a tunnel for passage of flexor carpi radialis tendon).

Flexor Retinaculum (Anterior carpal tunnel) v. Structures passing superficial to flexor retinaculum, from medial to lateral : 1 tendon of flexor C. U. 2 -ulnar N. 3 -ulnar artery. 4 -palmar cutaneous branch of ulnar N. 5 -tendon of palmaris longus. 6 -palmar cutaneous branch of median N. Cross section of the hand v. Structures passing deep to flexor retinaculum from medial to lateral : 1 -tendons of F. D. S + F. D. P in a common synovial sheath. 2 median N. + anterior interosseous branch. 3 -anterior interosseous artery. 4 -tendon of flexor pollicis longus. 5 -tendon of flexor carpi radialis.

Muscles of Anterior Compartment of Forearm 2/3 of ¾ of + interosseous membrane.

(( ) Impression on middle of lateral surface of shaft of radius Pronator Teres + Pronator Quadratus. Flexor carpi radialis

( Plmaris Longus ) Olecranon process of ulna+ upper 2/3 post. border of ulna Flexor Carpi Ulnaris v Their tendons pass superficial to flexor retinaculum

( ( ) ) (By 4 tendons into sides of middle phalanges of medial 4 fingers. ) Flexor Digitorum Superficialis Insertion : vby 4 tendons into medial 4 fingers, each tendon divides into 2 slips on palmar surface of proximal phalanx to surround tendon of flexor digitorum profundus. v. The 2 slips are inserted into sides of middle phalanx of medial 4 fingers.

From upper 2/3 of anterior surface of radius+ I. M. upper ¾ of antero-medial surface of ulna + I. M. Into base of Base of Flexor Pollicis Longus Flexor Digitorum Profundus v. Flexion of interphalangeal & metacarpo-phalangeal joints of thumb. medial 4 fingers.

Sensory nerves of dorsum of hand ØSuperficial branch of radial N. : skin of lateral 2/3 of back of hand. ØDorsal cutaneous branch of ulnar N. : skin of medial 1/3 of back of hand ØSkin of back of fingers by : 1 -dorsal digital branches of radial N. : skin of back of proximal phalanges of lateral 3 ½ fingers. 2 -palmar digital branches of median nerve : skin of back of middle & distal phalanges of lateral 3 ½ fingers. 3 -dorsal digital branches of ulnar N. : skin of back of proximal phalanges of medial 1 ½ fingers. 4 -palmar digital branches of ulnar N. : skin of back of middle & distal phalanges of medial 1 ½ fingers.

Contents of Lateral fascial compartment of forearm Upper 2/3 of It helps in initiation of pronation & supination Lower 1/3 of v. Blood supply : radial & brachial arteries. v. Nerve supply : radial N.

Lower 1/3 of (Upper 2/3 ) Styloid process of radius Dorsum of base of Brachioradialis Extensor carpi radialis longus.

Posterior fascial compartment of forearm v Superficial Group of Muscles : 1 -extensor carpi radialis brevis. 2 -extensor digitorum. 3 -extensor digiti minimi. 4 -extensor carpi ulnaris. 5 -anconeus. v Deep Group of Muscles 1 -supinator. 2 -abductor pollicis longus. 3 -extensor pollicis brevis. 4 -extensor pollicis longus. 5 -extensor indicis. v. Blood supply : posterior & anterior interosseous arteries of ulnar artery. v. Nerve supply : deep branch of radial N. (post. interosseous N. ).

Muscles of Posterior fascial Compartment of Forearm (Superficial muscles) Post. Interosseous N. (N. to Anconeous)

Muscles of Posterior fascial Compartment of Forearm (Deep muscles) Post. interosseous N. (Common ext. origin) + supinator crest & fossa of ulna V-shaped area, Upper 1/3 of front, lateral & back of radius

Extensor Retinaculum vit is a thickening of deep fascia that stretches across back of wrist and holds long extensor tendons in position. v. It converts grooves of posterior surface of distal ends of radius & ulna into 6 separate tunnels or compartments for passage of long extensor tendons, the tunnels are separated by fibrous septa. v. It is attached medially to pisiform bone & hook of hamate, and laterally to distal end of radius. Cross section of the hand

Extensor Retinaculum v. Structures passing superficial to extensor retinaculum from medial to lateral : 1 -dorsal(posterior) cutaneous branch of ulnar N. 2 -basilic vein. 3 cephalic vein. 4 superficial branch of radial N. Cross section of the hand v. Posterior carpal tunnel= Structures passing deep to extensor retinaculim in each compartments (from lateral to medial) : Tendons of 1 - abductor P. L +extensor P. B + radial artery. 2 -extensor C. R. L +extensor C. R. B. 3 -extensor pollicis longus. 4 -extensor digit. + extensor indicis 5 -extensor digiti minimi. 6 -extensor carpi ulnaris.

Structures passing deep to extensor retinaculum (posterior carpal tunnel) (from lateral to medial)

Structures passing deep to extensor retinaculum (posterior carpal tunnel)

Insertion of long extensor tendons ØExtensor digitorum muscle gives rise to 4 tendons for medial 4 fingers. ØTendon to index finger is joined on its medial side by tendon of extensor indicis, and tendon to little finger is joined on its medial side by 2 tendons of extensor digiti minimi. ØOn back of each finger, the extensor tendon expands to join the fascial expansion called extensor expansion. ØEach extensor expansion divides into : a central part, inserted into base of middle phalanx, and 2 collateral parts to insert into base of distal phalanx.

Dorsal extensor expansion ØEach dorsal extensor expansion receives the insertion of : 1 -an interosseous muscle on the medial side. 2 -an interosseous & lumbrical muscles on the lateral side.

Radial artery in dorsum of hand ØIt reaches back of hand by passing between lateral collateral ligament of wrist joint and tendons of abductor pollicis longus + extensor pollicis brevis. ØIt passes beneath tendon of extensor P. L to reach the interval between 2 heads of 1 st dorsal interosseous to enter palm of hand. v. Anatomic snuffbox : it is a skin depression on lateral side of wrist, bounded medially by tendon of extensor pollicis longus and laterally by tendons of abductor pollicis longus & extensor pollicis brevis. ØOn reaching palm, it curves medially between oblique & transverse heads of adductor pollicis to join deep branch of ulnar artery to form “deep palmar arch”.

Branches of radial artery on the dorsum of hand ØDorsal digital artery to lateral side of dorsum of the thumb. Ø 1 st dorsal metacarpal artery , which divides into 2 dorsal digital branches for adjacent sides of thumb & index finger.

Anatomic Snuffbox vit is a skin depression on lateral side of wrist, bounded medially by tendon of extensor pollicis longus and laterally by tendons of abductor pollicis longus & extensor pollicis brevis. v. Clinically , it is the site for radial artery pulsations.

Dorsal venous arch ØIt lies in superficial fascia (subcutaneous tissue) , proximal to metacarophalangeal joints , and drains on lateral side into cephalic V. and on medial side into basilic V. ØVenous blood from hand drains into the arch via dorsal digital veins.

Radial Nerve in lateral & posterior compartment ØIt pierces lateral intermuscular septum of lower arm to pass into cubital fossa. ØIt then passes in front of lateral epicondyle , between brachialis(medially) and / brachioradialis & ext. carpi radialis longus (laterally). At level of lateral epicondyle, it divides into superfical & deep branches. v. Branches : -muscular : lateral part of brachialis + brachioradialis + ext. C. R. longus. -articular : elbow joint. --Superficial branch : it is direct continuation of radial N. , descending deep to brachioradialis. Above wrist, it pierces deep fascia and turns backwards to supply skin of lateral 2/3 of back of hand + skin of back of proximal phalanges of lateral 3 1/2 fingers. -Deep branch (posterior interosseous N. ) : Arises from radial N. in cubital fossa in front of lateral epicondyle. It pierces supinator muscle to reach posterior compartment of forearm, between superficial & deep muscles to supply the extensors and ends in wrist joint. (so, it gives muscular & articular branches).

Anterior & posterior interosseous arteries (arteries of posterior compartment of forearm) ØThey arise from common interosseous artery, a short branch of ulnar artery in upper part of front of forearm, which divides into 2 branches : ØAnterior interosseous artery : descends in front of I. M. Above wrist , it pierces I. M. to reach back descending behind I. M. and takes part in anastomosis around wrist. ØPosterior interosseous artery: a small branch which passes above I. M. to reach back of forearm. It ends by anastomosing anterior interosseous artery and takes part in anastomosis around wrist. ØThe 2 arteries supply radius & ulna + muscles lying in front & behind I. M.

Anterior & posterior interosseous arteries

Anterior interosseous artery

Radial artery in the lateral side of forearm , where it deviates posteriorly to reach anatomical snuffbox on the dorsum of hand

Lower 1/3 of Front of Common ext. origin + post. Border of ulna Dorsum of base of Dorsum of Base of Extensor carpi radialis brevis & extensor carpi ulnaris.

1 - for 2 - Into its extensor expansion Extensor Digitorum & Extensor Digiti minimi v. Insertion of ext. digitorum : by 4 tendons into medial 4 fingers. v. Each tendon expand to form ext. expansion, which divides into central part & 2 collateral parts. v. Central part is inserted into post. surface of base of middle phalanx. v 2 collateral parts are inserted into post. surface of base of distal phalanx.

Olecranon process of ulna(lateral surface). Post. surface of shaft of radius Post. surface of shaft of ulna Anconeous

Middle of Post. surface of shaft of radius +ulna + I. M. Middle 1/3 of post. surface of radius +I. M. Middle 1/3 of Post. surface of shaft of ulna +I. M. Lower 1/3 of post. surface of ulna + I. M. Into extensor expansion of index finger Abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis.

Lateral epicondyle of humerus. + supinator crest& fossa of ulna Into V-shaped area in Neck & upper 1/3 of shaft of radius Supinator muscle.

Cutaneous nerves of palm ØPalmar cutaneous branch of median N. : supplies skin of lateral 2/3 of palm. ØPalmar cutaneous branch of ulnar N. : supplies skin of medial 1/3 of palm. ØLateral cutaneous N. of forearm or/superficial branch of radial N. : supplies skin over base of thenar eminence. ØSkin of Palmar surfaces of fingers is supplied by : 1 -palmar digital branches of median N…. For palmar surfaces of lateral 3 ½ fingers. 2 -palmar digital branches of ulnar N…for palmar surfaces of medial 1 ½ fingers.

Palmar aponeurosis ØIt is a triangular thickening of deep fascia, occuping central part of the palm. ØIts apex is directed upwards and is attached to flexor retinaculum and gives insertion to palmaris longus muscle. ØIts base is directed downwards and is divided into 4 slips for medial 4 fingers. ØEach slip divides into 2 bands which diverge from each other and pass backwards and finally fuse with the fibrous flexor sheath and deep transverse metacarpal ligaments. ØIts medial & lateral borders send fibrous septa into palm to form palmar fascial spaces. ØIts function to protect tendons, nerves & blood vessels in the palm.

Palmaris brevis muscle ØIt is a thin muscle which is present in superficial fascia of palm, in front of hypothenar eminence. ØOrigin : flexor retinaculum & palmar aponeurosis. ØInsertion : skin of medial side of palm. ØNerve supply : superficial terminal branch of ulnar N. ØFunction : it deepens cup of hand enables hand to hold a rounded objects.

Structures passing superficial to flexor retinaculum

The carpal Tunnel ØThe long tendons of fingers & thumb and median N. pass through the tunnel. The tendons of F. D. P. lie behind superficialis tendons, together in a common synovial sheath. ØTendon of F. P. L. muscle runs through lateral part of tunnel in its own synovial sheath. ØMedian N. passes beneath flexor retinaculum in a restricted space between F. D. S & F. C. R muscles.

Carpal tunnel syndrome It is a burning pain or ‘pins & needles’ along the distribution of median nerve to lateral 3 ½ fingers + weakness of thenar muscles (abductor P. brevis, flexor P. brevis + opponens pollicis). It is due to compression of median N. within the tunnel as a result of thickening of synovial sheaths of flexor tendons or arthritis of carpal bones. It needs surgical decompression of tunnel. No paresthesia over thenar eminence due to palmar cutaneous branch of median N. passes superficial to flexor retinaculum.

Fibrous flexor sheaths ØIt extends from head of metacarpal bone to base of distal phalanx. ØIts proximal end is open and is contineous with palmar aponeurosis. ØIts distal end is closed and is attached to palmar surface of distal phalanx. ØIts function to hold flexor tendons (F. D. S + F. D. P, & F. pollicis longus) and their synovial sheaths.

Flexor synovial sheaths ØSynovial sheath of tendon of flexor pollicis longus (radial bursa) : -begins above flexor retinaculum and extends to the insertion of tendon (distal phalanx). ØCommon flexor synovial sheath : surrounds the 8 tendons of F. D. S & F. D. P (ulnar bursa) -begins above the flexor retinaculum -ends in the middle of palm. -continuous with the synovial sheath of little finger. -the sheaths of index, middle & ring fingers do not communicate with the common sheath, they have digital synovial sheaths, that ends at distal phalanges.

Vincula tendinum ØThey are long threads (vincula longa) or short triangular bands (vincula brevia). ØThey are vascular folds of synovial membrane that connect the tendons to palmar surface of phalanges. ØTheir function : 1 -allow the long tendons to move smoothly beneath flexor retinaculum and fibrous flexor sheaths. 2 -carry blood supply to tendons

4 Lumbrical muscles ØOrigin : lateral sides of tendons of F. D. P. ØInsertion : pass backwards along lateral sides of metacarpo-phalangeal joints of medial 4 fingers into lateral sides of extensor expansions of these fingers. ØN. supply : lateral 2 lumbricals (1 st &2 nd )by median N. – medial 2 lumbricals(3 rd &4 th ) by deep branch of ulnar N. ØAction : with interossei, they flex metacarpo-phalangeal joints and extend interphalangeal joints of medial 4 fingers (Writing position).

Interossei muscles Ø 4 Palmar interossei & 4 dorsal interossei. ØOrigin : metacarpal bones. ØInsertion : proximal phalanges & dorsal extensor expansion. ØN. supply : deep branch of ulnar N. Anterior view ØAction : -palmar interossei : adduction of fingers to the middle line of middle finger. dorsal interossei : abduction of fingers from middle line of middle finger. -both lumbricals + interossei …. . ’’writing position’’

Origin & insertion & action of palmar & dorsal interossei muscles

Short muscles of thumb (thenar eminence muscles) ØAbductor pollicis brevis, laterally. ØFlexor pollicis brevis, medially. ØOpponens pollicis, deep. ØAdductor pollicis (obliqe & transvere heads). ØN. supply : all are supplied by median N. EXCEPT adductor pollicis by deep branch of ulnar N. v. Abduction & adduction = carpo-metacarpal joint. v. Flexion = metacarpo-phalngeal joint.

Short muscles of little finger (hypothenar eminence muscles) ØAbductor digiti minimi. ØFlexor digiti minimi. ØOpponens digiti minimi. ØN. supply : all these muscles are supplied by deep branch of ulnar N. Anterior view

Ulnar artery in the palm ØIt enters hand by passing superficial to flexor retinaculum, lateral to ulnar N. and pisiform bone. Anterior view ØIn the hand it divides into deep & superficial palmar branch. -superficial palmar branch : is a direct continuation of ulnar artery. It joins superficial palmar branch of radial to form superficial palmar arch, . in front of long flexor tendons and behind palmar aponeurosis. The curve of arch lies at level with the distal border of fully extended thumb. It gives 4 palmar digital arteries to the fingers. -deep branch of ulnar artery : passes backwards (accomppanied by deep branch of ulnar N. ) between abductor digiti minimi & flexor digiti minimi to join radial artery to form deep palmar arch.

Branches of Superficial palmar arch v. Palmar digital artery …to medial side of little finger. v 3 common palmar digital arteries : each one divides into 2 palmar digital branches to adjacent sides of fingers. They are joined with : common palmar metacarpal arteries of deep palmar arch.

Radial artery in the palm ØIt leaves forearm by winding around lateral aspect of wrist into dorsum of hand. ØIt leaves dorsum of hand by turning forward between the 2 heads of 1 st dorsal interosseous muscle. ØIt enters palm curving medially between the oblique & transverse heads of adductor pollicis to join deep branch of ulnar artery to form deep palmar arch, which lies beneatn long flexor tendons and in front of metacarpal bones & interosseous muscles. The curve of arch lies at a level with proximal border of extended thumb.

Branches of radial artery in the palm : ØArteria radialis indicis : supplies lateral side of index finger. ØArteria princeps pollicis : divides into two to supply lateral & medial sides of thumb. Branches of deep palmar arch: Ø 3 common palmar metacarpal arteries : they run in 2 nd , 3 rd &4 th intermetacarpal spaces to end by joining common palmar digital arteries at roots of fingers.

Median nerve of the palm ØCourse : -it leaves forearm to enter hand by passing deep to flexor retinaculum. –it ends in the palm by dividing into terminal lateral & medial branches. v. Branches in the hand : -the 2 terminal branches give rise to : 1 -muscular branches : to supply 5 Ms. (Abductor pollicis brevis, flexor pollicis brevis, Opponens pollicis) + lateral 2 lumbricals (1 st & 2 nd ). 2 -cutaneous branches : by 5 palmar digital branches to supply skin of palmar surface of lateral 3 ½ of fingers. They also supply nail beds & skin over back of middle and distal phalanges of same fingers. vpalmar cutaneous branch of median nerve : in the forearm and crosses superficial to flexor retinaculum to supply skin of lateral 2/3 of palm.

Ulnar nerve in the palm ØCourse : vpalmar cutaneous branch of ulnar nerve : -arises in forearm above wrist, passing superficial to flexor retinaculum to supply skin of medial 1/3 of palm of hand. -it enters hand by passing superficial to flexor retinaculum, it divides into terminal superficial & deep branch. -superficial branch : -passes deep to palmaris brevis to supply it. -it gives 2 palmar digital branches for medial 1 ½ fingers. -deep branch : -passes backwards between abductor D. M. & flexor D. M. and then turns laterally across palm deep to flexor tendons proximal to deep palmar arch. -supplies 14 Ms. (3 hypothenar + medial 2 lumbricals 3 rd , 4 th + 4 palmar interosseoi + 4 dorsal interosseoi + adductor pollicis).

Pulp space of fingers ØDeep fascia of pulp of each finger fuses with periosteum of terminal phalanx. ØEach pulp space is filled with fat and is subdivided by fibrous septa. ØTerminal branch of digital artery that supplies diaphysis of terminal phalanx, runs through this pulp space, while the blood supply of epiphysis is proximal to pulp space. ØFelon (pulp –space infection) : common case leads to infection of terminal phalanx and necrosis of diaphysis, but epiphysis is saved.

Palmar fascial spaces ØFrom medial border of palmar aponeurosis, a fibrous septum passes backward and attached to 5 th metacarpal bone. Medial to this septum is a medial fascial compartment containing 3 hypothenar muscles + loose C. T. ØFrom the lateral border of palmar aponeurosis, a second fibrous septum passes obliquely backward to 3 rd metacarpal bone. It divides palm into thenar space (contains 1 st lumbrical) & midpalmar space (contains 2 nd , 3 rd , 4 th lumbricals). Ø 3 rd fibrous septum passes backward from lateral side to attach to 1 st metacarpal, lateral to this septum a lateral fascial compartment containing muscles of thenar eminence.