Humerus - Exam Preparation Notes

HUME ERUSRIGHTTYPE:-Itis a typical long bone. It develops by carbilagenous ossification.POSITION:- It is the bone of arm.IDENTIFICATION OF SIDE (Rt or Lt)(1) Upper end is identified by the hemispherical head.(ii) Lowen end is identified by trochlea and capitulum.(iii)Medial side is identified by the head (directed medially)ivPosterior surface is identified by the deep olecranon fossain the lower end.HUMERUS : GENERAL FEATURESThe humerus is composed of a shaft & 2 expanded endsupper and lower -Human materryTHE UPPER ENDFor ExamHead2 Tuberosities2 Necksgreater & Lesser)(Anatomical & Surgical)HEAD OF THE HUMERUS(2)Forms less than 1/2 sphere and covered with articular carbilage(2) Directed upwards, medially and backwards.(in the living)(3) Articulates with the glenoid cavity of the scapula at theShoulder joint.ANATOMICAL NECK1 The from constriction the 2 tuberosites. close to the margins of the head separating it2 It gives attachment where the to the capsule of shoulder joint (exceptmedially the capsule descends for 1cm. to reachsurgical neck).SURGICAL NECK(1Junction between the upper end the shaft.(2) lies about 1 finger breadth below the head & the2 tuberosities.(3) It is related medially to the circumflex nerre and postcircumflex humeral vessels. HUMERUS2LESSER TUBEROSITYDIPANKAR RAY(1) It projects forwards medial to the intertubercidar sulcus.R Show one facet on its upper part (For the Subscrpularis M.)3Lateral edge is continuous below with the medial lipof the bicipital groove.GREATER TUBEROSITYHuman Anatory for Exam(1) lies on the lateral part of the upper and of humerus.(2) Anterior of margin is continuous below with. the lateral lipthe bicipital groove.3Show 3 forets for murcular attachments on its upper andpast aspects.INTERTUBERCULAR SULCUS (BICIPITAL GROOVE(1) Lies shaft between 2 tuberosities and extends to the upper 1/3 of the2 It has aflour and 2lips (medial and latera) for muscularattachments.(3) Lodges the tendon of the long head of biceps musde.(4) Upper part is bridged over by the transverse human ligamentTHE LOWER END(A)ARTICULAR PARTSrepresenting modified condytes of lower end.Include the trochlea and the CapitulumTROCHLEARully like process covering the anterior, inferior andArticulates with the trochlear notch of ulna.posterior parts of the medial articular part of lower endMedial lip projects more down than the lateral lip.CAPITULUM -Small ball like process lying lateral to trochleaIt covers the anterior and inform surfaces only of the larmalpart of the articular surface of the lower limb.Articulates with the upper surface of the head of radius HUMERUS3BEPICONDYLESMEDIAL EPICONDYLEProjects from the medial side of the lower end.More prominent than the lateral epicondyle and is subcutenous.Ant surface shows a rough impression for muscular attachment.Post surface may show a shallow groove (for ulnar here).RAYLATERAL EPICONDYLEProjects from the lateral side of the lower end (less prominentthan medial epirondyle).Anterior and lateral surfaces show rough impressions formuscliar attachments.CTHE 3 FOSSAEHuman Anatomy ExamForOLECRANON FOSSADeep depression on the post-surface of the lower end abovethe trochlea.It lodges the tip of the olecranon process of uha when theelbow is extended.RADIAL FOSSAVery shallow depression on the anterior surface of the lower endabove capitulum.Receives the margin of the head of the radius in full flexonof elbowCORONOID FOSSAShallow depression above the trochler on the anterior surfaceof the lower end.Receives the tip of the coronoid process of ulna in fullflexion of elbow. HUMERUS4SHAFT OF HUMERUSIt has 3 borders and 3 surfaces. Upper 1/2 is rounded in cross sectionlower 1/2 is trianguler in cross section.BORDERS OF HUMERUSDIPWWAR RAYANTERIOR BORDERLower part is smooth and round.Upper part forms the lateral lip of the bicipital groove.Middle part forms the anterior boundary of the deltoid tuberosity.MEDIAL BORDERExcends from the lesser tuberosity above to the medial epicondyle below.Upper part ill defined while its lower part end (above theLATERAL BORDERmedial epicandale) is prominent and medial supra condylar ridge.Human AnatomyFor ExamExtends from the back of the greater tuberosity above to thelateral epiandyie below,Lower part is prominent and called lateral Suprasondylan ridge.SURFACES OF THE HUMERUSANTEROMEDIAL SURFACElies between the ant and med borders.Upper 1/3 presents the bicipital groove (having floor and 2 lips; lat & Med).A little below its middle it shows a nutrient faramen (directed downwards)ANTERO LATERAL SURFACElies between the anterior and the lateralMiddle part a V-shaped rough area calledshows borders.deltoid tuberosity.POSTERIOR SURFACElies between the medial and lateral bordersUpper 1/3 show an oblique ridge passing downwards and laterallyMiddle 1/3 is crossed by the spiral groove (for radial m.)passing downwards & laterally. HUMERUS (5)HUMERUS: PARTICULAR FEATURESLIGAMENTS ATTACHEDCAPSULE OF SHOULDER JOINTAttached to the anatomical neck exceptmedially where it descends for 1cm-to reach the surgical neck.CORACO-HUMERAL LIGAMENTAttached to the greater tuberosity andthe uppersmast part of the anatomical meekGLENO-HUMERAL LIGAMENTSSuperior, Middle and Inferior.The Superior is attached just above the lesser tuberosity.The Middle, is attached just below the lesser tuberosity.-The Inferior, is attached to the lower part of anatomical neek.TRANSVERSE HUMERAL LIGAMENTDIPANKAR RAYAttached between the 2 tuberosites across the upper part ofinter tubercular sulcus.LATERAL INTERMUSCULAR SEPTOMHuman Anatomy For ExamAttached to the lateral suprocondylar ridge and lateralborder of humeras.MEDIAL INTERMUSCULAR SEPTUMAttached to the medial -supracondylar ridge andmedial border of humerus.CAPSULE OF ELBOW JOINTAttached around the articular surfaces of the lower endabove the 3 fossae.MUSCLES ATTACHED(A)3 MUSCLES ARE INSERTED INTO THE GREATER TUBEROSITY1SUPRASPINATUS MUSCLE:- Inserted into the upper most fact ofgreater tuberosity.(2) INFRASPINATUS MUSCLE:- - Inserted into the middle facet ofgreater tuberosity.3TERES MINOR MOSCLE :- Inserted into the lower faret of thegreater tuberosity. HUMERUS683 MUSCLES ARE INSERTED INTO THE BICIPITAL GROOVETERES MAJOR MUSCLE :- Inserted into the medial lip of Bicipitalgroove2 LATISSIMUS DORSI MUSCLE :- Inserted into the floor of the bicipitalgroove.(3)PECTORALIS MAJOR MUSCLE:- Inserted into the lateral lip of thebicipital groove.DIPANKAR RAYeSubscapularis Muscle is inserted into the lesser tuberosityDTHE B-e-D MUSCLESHuman AnatomyFor Exam1 BRACHIALS MUSCLE:- Arises from the Tower 1/2 of the anterioraspect of the shaft.2CORACO BRA CHIALIS:- Inserted into the middle of the medial borderof the humerus.(3) DELTOID MUSCLE:- Inserted into the deltoid tuberosity.E3 MUSCLES ARISE FROM SUPRACONDYLAR RIDGES(1) BRACHIDRADIALIS :- Arises from the upper 2/3 of lateral supracondy lar ridge.(2) EXT CARPI RADIALIS LONGUS:- Arises from the lower 1/3 of the lateralSupracondylar ridge.(3) PRONATOR TERES (HUMERAL HEAD):- Arises from the lower part of(F)3 MUSELES ARISE FROM THE BACK OF HUMERUSmedial supracondy lar ridge.(1)LATERAL HEAD OF TRICEPS :- Arises from the oblique ridge in theupper 1/3 of posterior surface(2) MEDIAL HEAD OF TRICEPS:- Arises from the whole post surface(3) ANCONEUS :- Arises from the back of lateral epicondyle.below the spiral groove.(G) MUSCLES ARISING FROM THE FRONT OF THE EPRONDYLES(1)COMON FLEXOR ORIGIN:- From the front of the medial epicondyle2COMMON EXTENSOR ORIGIN:- From the front of the lateral epicondyle.