ExperimentalManualofHumanAnatomythe head of the radius with the capitulum of the humerus. The proximal radioulnar joint is a pivotJoint between the circular articularfacet of the head of the radius and theradial notchof theulna.Itis surrounded by the strong annular ligament of radius, attached to the margin of the notch.Thejoints mentioned above are connected together by a capsule, which is thin and loose anteriorly andposteriorly, but thickened medially and laterally by the ulnar and the radial collateral ligaments. Theulnar collateral ligament is a triangular band attaches to the medial epicondyle of the humerus andthe medial margin of the olecranon, and the coronoid process. The radial collateral ligament is alsoatriangularbandfanningoutfromthelateral epicondyleofthehumerus aboveandblendswiththeannular ligament below.The annular ligament is a strong fibrous band encircling the head of theradius andformsa nearlycompleteosseofibrous ringforholdingthehead of theradiusThe elbow joint is a simple hinge joint, and allows of flexion and extension.Although thehumeroradial joint is a ball-socket joint, its movements are limited by the humeroulnar jointPossible movements at the jointarerotation,flexion andextension.Thehead oftheradiuscan rotateattheproximal radioulnar joint,carryingthehandtopronation and supination,which arepeculiarto the human beings.The olecranon, themedial epicondyleand lateral epicondyle ofthe humerusare a beeline during the elbow jointfull extension, but they are an isoceles triangle during the elbowjointflexion to aright angle.Thisrelation is possibly changedwith thefracture or dislocation of theelbowjoint(3) Joints of Ulna and RadiusThese joints include the following three:the proximal radioulnar joint,the interosseousmembrane oftheforearm and thedistal radioulnarjoint.Theproximal joint is apartof the elbowjoint, connects the upper end of ulna and radius (see above).Thedistal radioulnar joint is formedby the head of the ulna and the ulnar notch of the radius. The interosseous membrane of the forearmmay be considered as a fibrous joint between the radius and the ulna. The membrane is a strongband offibrous tissue with its fibers descending obliquely downward and mediallyfrom theradiusto the ulna, It is loosed in full pronation and supination, but is tightest in pronation midway26
Experimental Manual of Human Anatomy 26 the head of the radius with the capitulum of the humerus. The proximal radioulnar joint is a pivot Joint between the circular articular facet of the head of the radius and the radial notch of the ulna. It is surrounded by the strong annular ligament of radius, attached to the margin of the notch. The joints mentioned above are connected together by a capsule, which is thin and loose anteriorly and posteriorly, but thickened medially and laterally by the ulnar and the radial collateral ligaments. The ulnar collateral ligament is a triangular band attaches to the medial epicondyle of the humerus and the medial margin of the olecranon, and the coronoid process. The radial collateral ligament is also a triangular band fanning out from the lateral epicondyle of the humerus above and blends with the annular ligament below. The annular ligament is a strong fibrous band encircling the head of the radius and forms a nearly complete osseofibrous ring for holding the head of the radius. The elbow joint is a simple hinge joint, and allows of flexion and extension. Although the humeroradial joint is a ball-socket joint, its movements are limited by the humeroulnar joint. Possible movements at the joint are rotation, flexion and extension. The head of the radius can rotate at the proximal radioulnar joint, carrying the hand to pronation and supination, which are peculiar to the human beings. The olecranon, the medial epicondyle and lateral epicondyle of the humerus are a beeline during the elbow joint full extension, but they are an isoceles triangle during the elbow joint flexion to a right angle. This relation is possibly changed with the fracture or dislocation of the elbow joint. (3) Joints of Ulna and Radius These joints include the following three: the proximal radioulnar joint, the interosseous membrane of the forearm and the distal radioulnar joint. The proximal joint is a part of the elbow joint, connects the upper end of ulna and radius (see above). The distal radioulnar joint is formed by the head of the ulna and the ulnar notch of the radius. The interosseous membrane of the forearm may be considered as a fibrous joint between the radius and the ulna. The membrane is a strong band of fibrous tissue with its fibers descending obliquely downward and medially from the radius to the ulna. It is loosed in full pronation and supination, but is tightest in pronation midway
ExperimentalManualofHumanAnatomyThemovements ofthe jointsconsistof pronationand supination duringwhichtheradiusrotatesaround an axis which extendsfrom the center of the head ofthe radius to the middle of the head ofthe ulna.(4) Joints oftheHandThe Joints of the hand include the following: the wrist joint, the intercarpal joints, thecarpometacarpal joints, the intermetacarpal joints, the metacarpophalangeal joints and theinterphalangeal joints.1)The wrist joint or radiocarpal joint is ellipsoid joint. The articular fossa isformed by distal endof the radius and the lower surface of the articular disc beneath the head of ulna: and the articularhead by proximal surface of the navicular lunate,and triangularbones.Thecapsule ofthewrist jointis loose and strengthened by the surrounding ligaments.The strongest of allthese ligaments is thepalmar ligament, attached to the front of the capsule. The movements permitted in the wrist jointareflexionextension,abduction,adductionandcircumduction2)The intercarpal joints are plane joints between theneighboring carpal bones.Theymay besubdivided into three sets: the joints of the proximal row of carpal bones, the joints ofthe distal rowof carpal bones, and the joints between the two rows of carpal bones, or the midcarpal joints. Themovements ofthese joints arelimitedand consideredasapart of allmovements of thewrist joint3) The carpometacarpal joints are formed by the distal row of the carpal bones and the bases of themetacarpals. They share a common capsule with the intercarpal joints, and the movements of themare slight except the carpometacarpal jointofthe thumb.Thecarpometacarpal jointofthethumb isformedbythebaseofthefirstmetacarpal andtrapezium.Thecapsuleofthejointisthickbut looseand forms a separate joint cavity from the rest of the carpus. The joint is saddle-shaped and enjoysa great freedom of movements. The movements permitted in the Joint are abduction and adductionin a plane at right angles to the palm, flexion and extension in the plane of thepalm of the handcircumduction and opposition.The functional importanceof the thumb is the ability to be opposedto the fingers and is peculiar to the human beings.27
Experimental Manual of Human Anatomy 27 The movements of the joints consist of pronation and supination during which the radius rotates around an axis which extends from the center of the head of the radius to the middle of the head of the ulna. (4) Joints of the Hand The Joints of the hand include the following: the wrist joint, the intercarpal joints, the carpometacarpal joints, the intermetacarpal joints, the metacarpophalangeal joints and the interphalangeal joints. 1) The wrist joint or radiocarpal joint is ellipsoid joint. The articular fossa is formed by distal end of the radius and the lower surface of the articular disc beneath the head of ulna: and the articular head by proximal surface of the navicular lunate, and triangular bones. The capsule of the wrist joint is loose and strengthened by the surrounding ligaments. The strongest of all these ligaments is the palmar ligament, attached to the front of the capsule. The movements permitted in the wrist joint are flexion extension, abduction, adduction and circumduction. 2) The intercarpal joints are plane joints between the neighboring carpal bones. They may be subdivided into three sets: the joints of the proximal row of carpal bones, the joints of the distal row of carpal bones, and the joints between the two rows of carpal bones, or the midcarpal joints. The movements of these joints are limited and considered as a part of all movements of the wrist joint. 3) The carpometacarpal joints are formed by the distal row of the carpal bones and the bases of the metacarpals. They share a common capsule with the intercarpal joints, and the movements of them are slight except the carpometacarpal joint of the thumb. The carpometacarpal joint of the thumb is formed by the base of the first metacarpal and trapezium. The capsule of the joint is thick but loose, and forms a separate joint cavity from the rest of the carpus. The joint is saddle-shaped and enjoys a great freedom of movements. The movements permitted in the Joint are abduction and adduction in a plane at right angles to the palm, flexion and extension in the plane of the palm of the hand, circumduction and opposition. The functional importance of the thumb is the ability to be opposed to the fingers and is peculiar to the human beings
ExperimentalManualofHumanAnatomy3)Theintermetacarpal jointsareplanejointsformedbythearticulationsbetweentheopposedsides of the bases of the second tofifth metacarpal bones. The three articular cavities are connectedwiththecavitiesof thecarpometacarpal jointandwitheachother4)The metacarpophalangeal joints areformedbythe head of the metacarpal bones and thebasesofthe proximal phalanges. The capsule ofthese joints is loose and thin. Each joint has a thick palmarligament and two strong collateral ligaments placed on thesides of the joint.These ligamentsbecometightintheflexedpositionof the joints,butlooseintheextendedposition.Themovementsofthese joints areflexion,extension,abduction,adductionand circumduction.Themovementsofabduction and adduction are very limited and cannot be performed when the fingers are flexed.5)The interphalangeal joints or articulation of the digits aretypical hinge joints.They are formedby the heads of the phalanx proximally and the base of the phalanx distally.The ligaments of thesejoints are similar to those in the metacarpophalangeal joints havinga palmar and two collateralligaments. The movements permitted in the joints are flexion and extension, these movements aremore extensivebetween thefirst and secondphalangesthan betweenthesecond and third.Theextent of flexion is very considerable.(Mei Yang)Chapter 4 Bones and articulations of lower limbLearningObjectives:1.Identifythecomposition,division,positionandfunctionof lowerlimbbones2.Describe the position, shape and structure ofhip bone,femer, tibia and fibula3.Comprehend the composition, characteristics and movementforms of pelvic girdle, hip joint,28
Experimental Manual of Human Anatomy 28 3) The intermetacarpal joints are plane joints formed by the articulations between the opposed sides of the bases of the second to fifth metacarpal bones. The three articular cavities are connected with the cavities of the carpometacarpal joint and with each other. 4) The metacarpophalangeal joints are formed by the head of the metacarpal bones and the bases of the proximal phalanges. The capsule of these joints is loose and thin. Each joint has a thick palmar ligament and two strong collateral ligaments placed on the sides of the joint. These ligaments become tight in the flexed position of the joints, but loose in the extended position. The movements of these joints are flexion, extension, abduction, adduction and circumduction. The movements of abduction and adduction are very limited and cannot be performed when the fingers are flexed. 5) The interphalangeal joints or articulation of the digits are typical hinge joints. They are formed by the heads of the phalanx proximally and the base of the phalanx distally. The ligaments of these joints are similar to those in the metacarpophalangeal joints having a palmar and two collateral ligaments. The movements permitted in the joints are flexion and extension, these movements are more extensive between the first and second phalanges than between the second and third. The extent of flexion is very considerable. (Mei Yang) Chapter 4 Bones and articulations of lower limb Learning Objectives: 1. Identify the composition, division, position and function of lower limb bones. 2. Describe the position, shape and structure of hip bone, femer, tibia and fibula. 3. Comprehend the composition, characteristics and movement forms of pelvic girdle, hip joint
ExperimentalManualofHumanAnatomyknee joint and ankle joint.The lower limb is specialized for locomotion, bearing weight, and maintaining equilibrium,forthis reason,thebones of lower limbs aremoremassivethan thoseofupper limbSection 1 Bones of upper limbThebonesof lower limbare composed of thepelvicgirdleand thebonesof freelower limb.Thepelvicgirdleis connected with the sacrum and coccyxto form the bony pelvis.Using theillustrations as a reference, find thefollowing bones to observeL.Pelvic girdleThe pelvic girdleis formed by two hip bones, which articulate posteriorly with the sacrum and meetin front at the pubic symphysis. The pelvic girdle, the sacrum and coccyx together form the bonypelvis. The hip bones is an irregular bone, constricted in the middle and expended above and belowEachhip boneofa newborn consists ofthreebones:a superior ilium,a posteroinferior ischium,andan anteroinferior pubis.1. IliumThe ilium is the large superior part ofthe hip bone. It is divided into two parts, the body ofiliumand the ala of ilium by the arcuate line. The body of ilium forms a part of the acetabulum. The alaof ilium is the upper expanded portion. Its superior border is termed as the iliac crest. The anteriorand posteriorends of iliac crest arecalled the anteriorsuperior iliac spine and posteriorsuperioriliac spine,and afewcentimeters belowthese two spines are the anteriorinferioriliacspine and posterior inferior iliac spine, respectively. There is an eminence, called the tubercle ofiliac crest,on the outer lipofiliaccrest.The internal surface of theala presents a large smoothconcave area named asthe iliacfossa, which is bounded above bythe iliac crest and belowbyaroundedridgeknownas the arcuate line.Theexternal surface of theala is called theglutealsurfacecontributingtotheattachmentofgluteusmuscles29
Experimental Manual of Human Anatomy 29 knee joint and ankle joint. The lower limb is specialized for locomotion, bearing weight, and maintaining equilibrium, for this reason, the bones of lower limbs are more massive than those of upper limb. Section 1 Bones of upper limb The bones of lower limb are composed of the pelvic girdle and the bones of free lower limb. The pelvic girdle is connected with the sacrum and coccyx to form the bony pelvis. Using the illustrations as a reference, find the following bones to observe. I.Pelvic girdle The pelvic girdle is formed by two hip bones, which articulate posteriorly with the sacrum and meet in front at the pubic symphysis. The pelvic girdle, the sacrum and coccyx together form the bony pelvis. The hip bones is an irregular bone, constricted in the middle and expended above and below. Each hip bone of a newborn consists of three bones: a superior ilium, a posteroinferior ischium, and an anteroinferior pubis. 1. Ilium The ilium is the large superior part of the hip bone. It is divided into two parts, the body of ilium and the ala of ilium by the arcuate line. The body of ilium forms a part of the acetabulum. The ala of ilium is the upper expanded portion. Its superior border is termed as the iliac crest. The anterior and posterior ends of iliac crest are called the anterior superior iliac spine and posterior superior iliac spine, and a few centimeters below these two spines are the anterior inferior iliac spine and posterior inferior iliac spine, respectively. There is an eminence, called the tubercle of iliac crest, on the outer lip of iliac crest. The internal surface of the ala presents a large smooth concave area named as the iliac fossa, which is bounded above by the iliac crest and below by a rounded ridge known as the arcuate line. The external surface of the ala is called the gluteal surface contributing to the attachment of gluteus muscles
ExperimentalManualofHumanAnatomy2. Ischium It comprises a body and a ramus. The upper part of the body formsposteroinferior two-fifths of the acetabulum. On its posterior border there is a thin and pointedtriangular eminence known as the ischial spine.Above the spine, below the posterior inferior iliacspine, is the greater sciatic notch; and below the ischial spine is the lesser sciatic notch.Thelower part of the dorsal surface of ischial body shows a roughened projection called the ischialtuberosity, which is palpable. The lower end of the ischial body turns forwards, upwards andmedially to continue as the ramus of ischium.The ramus joins the inferior ramus of pubis.3. Pubic The pubis has a body, a superior ramus and an inferior ramus. The body forms theanteroinferior one-fifth of the acetabulum. The junction of the pubic body with the ilium presentsa roughtuber called the iliopubic eminence.The superiorramus extends fromthebody to themedian planewhere itturnsdownto continueas the inferiorramus.Themedial surfaceofthejunction between the two rami is a rough oval surface called the symphysial surface, whicharticulates with itsfellowof the opposite side by the interpubic disc toform the pubic symphysis.Theupperborder of the superior ramus is sharp and called thepectenpubis, which continues withthe arcuate line posteriorly and ends at the pubic tubercle anteriorly. The pubic crest is aroughridge extending from thepubic tubercleto the upper border ofpubic symphysis.Belowthesuperiorramus is a groovetermed as theobturatorgroove.The inferior ramus of pubis passesbackwards, downwards and laterally to join the ramus of ischium.The obturator foramen is an oval space surrounded by the bodies and rami of pubis and ischium,and is closed by the obturator membrane except the obturator groove.4. The acetabulumis a deep cup-shaped hemispherical depression on the outer aspect ofhipbone,about its centre,and is directed laterally,downwards and forwards.It isformed superiorlyby the ilium, anteroinferiorlyby the pubis, and posteroinferiorly by the ischium.Thedeficiency ofthe inferior part of acetabular margin is named as the acetabular notch.A horse-shoe-shapedarticular surface seen on the acetabulum is the lunate surface which articulates with the head offemur.30
Experimental Manual of Human Anatomy 30 2. Ischium It comprises a body and a ramus. The upper part of the body forms posteroinferior two-fifths of the acetabulum. On its posterior border there is a thin and pointed triangular eminence known as the ischial spine. Above the spine, below the posterior inferior iliac spine, is the greater sciatic notch; and below the ischial spine is the lesser sciatic notch. The lower part of the dorsal surface of ischial body shows a roughened projection called the ischial tuberosity, which is palpable. The lower end of the ischial body turns forwards, upwards and medially to continue as the ramus of ischium. The ramus joins the inferior ramus of pubis. 3. Pubic The pubis has a body, a superior ramus and an inferior ramus. The body forms the anteroinferior one-fifth of the acetabulum. The junction of the pubic body with the ilium presents a rough tuber called the iliopubic eminence. The superior ramus extends from the body to the median plane where it turns down to continue as the inferior ramus. The medial surface of the junction between the two rami is a rough oval surface called the symphysial surface, which articulates with its fellow of the opposite side by the interpubic disc to form the pubic symphysis. The upper border of the superior ramus is sharp and called the pecten pubis, which continues with the arcuate line posteriorly and ends at the pubic tubercle anteriorly. The pubic crest is a rough ridge extending from the pubic tubercle to the upper border of pubic symphysis. Below the superior ramus is a groove termed as the obturator groove. The inferior ramus of pubis passes backwards, downwards and laterally to join the ramus of ischium. The obturator foramen is an oval space surrounded by the bodies and rami of pubis and ischium, and is closed by the obturator membrane except the obturator groove. 4. The acetabulum is a deep cup-shaped hemispherical depression on the outer aspect of hip bone, about its centre, and is directed laterally, downwards and forwards. It is formed superiorly by the ilium, anteroinferiorly by the pubis, and posteroinferiorly by the ischium. The deficiency of the inferior part of acetabular margin is named as the acetabular notch. A horse-shoe-shaped articular surface seen on the acetabulum is the lunate surface which articulates with the head of femur