 section 49 of Gray's Anatomy Part 1. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Jennifer Stearns. Anatomy of the Human Body Part 1 by Henry Gray. Section 49, Tarsus. The skeleton of the foot consists of three parts, the tarsus, the metatarsus, and phalanges. The tarsus, also tarsy. The tarsal bones are seven in number, namely the calcaneus, talsus, cuboid, navicular, and the first, second, and third cuneiforms. The calcaneus, the calcaneus is the largest of the tarsal bones. It is situated at the lower and back part of the foot, serving to transmit the weight of the body to the ground, and forming a strong lever for the muscles of the calf. It is irregularly cuboidal in form, having its long axis directed forward and lateralward. It presents, for examination, six surfaces, surfaces. The superior surface extends behind onto that part of the bone, which projects backward to form the heel. This varies in length in different individuals, as convex side to side, concave from before backward, and supports a mass of fat placed in front of the tendo calcaneus. In front of this area is a large, usually somewhat oval-shaped facet, the posterior articular surface, which looks upward and forward. It is convex from behind forward, and articulates with the posterior calcaneal facet on the under surface of the talus. It is bounded anteriorly by a deep depression, which is continued backward and medialward, in the form of a groove calcaneus sulcus. In the articulated foot, this sulcus lies below a similar one on the under surface of the talus, and the two form a canal, sinus tarsae, for the lodgment of the interosseous talocalcaneal ligament. In front and to the medial side of this groove is an elongated facet, concave from behind forward, and with its long axis directed forward and lateralward. This facet is frequently divided into two by a notch. Of the two, the posterior, and larger, is termed the middle articular surface. It is supported on a projecting process of bone, the sustentaculum tally, and articulates in the middle calcaneal facet on the under surface of the talus. The anterior articular surface is placed on the anterior part of the body, and articulates with the anterior calcaneal facet on the talus. The upper surface, anterior and lateral to the facets, is rough for the attachment of ligaments, and for the origin of the extensor digitorum brevis. The inferior or plantar surface is uneven, wider behind than in front, and convex from side to side. It is bounded posteriorly by a transverse elevation, the calcaneal tuberosity, which is depressed in the middle and prolonged at either end into the lateral process. The lateral process, small, prominent, and rounded, gives origin to the part of the abductor digiti quinti, the medial process, broader and larger gives attachment by its prominent medial margin to the abductor talususus, and in front of the flexor digitorum brevis in the plantar aponeurosis. The depression behind the processes gives origin to the abductor digiti quinti. The rough surface in front of the processes gives attachment to the long plantar ligament, and to the lateral head of the quadratus plantae, to a prominent tubercle near the anterior part of the surface, as well as to a transverse groove in front of the tubercle, is attached to the planter calcaneal cuboid ligament. The lateral surface is broad behind and narrow in front, flat and almost subcutaneous. Near its center is a tubercle for the attachment of the calcaneal fibular ligament. At its upper and anterior part, this surface gives attachment to the lateral tallow calcaneal ligament, and in front of the tubercle it presents a narrow surface marked by two oblique grooves. The grooves are separated by an elevated ridge or tubercle, the tracheular process, peroneal tubercle, which varies much in size in different bones. The superior groove transmits the tendon of the peroneus brevis, the inferior groove, that of the peroneus longus. The menial surface is deeply concave. It is directed obliquely downward and forward, and serves for the transmission of the planter vessels and nerves into the sole of the foot. It affords origin to a part of the cordratus plantae. At its upper and fore part is horizontal eminence, the sustenta culum tally, which gives attachment to a slip of the tendon of the tibialis posterior. This eminence is concave above and articulates with the middle calcaneal articular surface of the talus. Below it is grooved for the tendon of the flexor, talusus longus. Its anterior margin gives attachment to the planter calcaneo navicular ligament and its medial to a part of the deltoid ligament of the ankle joint. The anterior or cuboid articular surface is of a somewhat triangular form. It is concave from above downward and lateralward, and convex in a direction at right angles to this. Its medial border gives attachment to the planter calcaneo navicular ligament. The posterior surface is prominent, convex, wider below than above, and divisible into three areas. The lowest of these is rough and covered by the fatty and fibrous tissue of the heel. The middle, also rough, gives insertion to the tendo calcaneus and the planteris, while the highest is smooth and is covered by a bursa, which intervenes between it and the tendo calcaneus. Articulations. The calcaneus articulates the two bones, the talus and cuboid, the talus, astragalus ankle bone. The talus is the second largest of the tarsal bones. It occupies the middle and upper part of the tarsus, supporting the tibia above, resting upon the calcaneus below, articulating on either side with the malleoli, and in front with the navicular. It consists of a body, a neck, and a head. The body, corpus tally. The superior surface of the body presents, behind, a smooth, trocular surface, the troculea, for articulation with the tibia. The troculea is broader in front than behind, convex from before backward, slightly from cave, from side to side. In front it is continuous with the upper surface of the neck of the bone. The inferior surface presents two articular areas, the posterior and middle calcaneal surfaces, separated from one another by a deep groove, the sulcus tally. The groove runs obliquely forward and lateralward, becoming gradually broader and deeper in front. In the articulated foot, it lies above a similar groove, upon the upper surface of the calcaneus, and forms with it a canal, sinus tarsi, filled up in the fresh state by the interosseous tallo-calcaneal ligament. The posterior calcaneal articular surface is large, and of an oval or oblong form. It articulates with a corresponding facet, on the upper surface of the calcaneus, footnote, sul, journal of anatomy and physiology, volume 38, pointed out that in about 10% of bones, a small triangular facet continuous with the posterior calcaneal facet is present at the junction of the lateral surface of the body with the posterior wall of the sulcus tally, and footnote, and is deeply decayed in the direction of its long axis, which runs forward and lateralward at an angle of about 45 degrees with a median plane of the body. The middle calcaneal articular surface is small, oval in form and slightly convex. It articulates with the upper surface of the substantive cum tally of the calcaneus. The medial surface presents at its upper part a pear-shaped articular facet for the medial malleolus, continuous above with the trochlea. Below the articular surface is a rough depression for the attachment of the deep portion of the deltoid ligament of the ankle joint. The lateral surface carries a large triangular facet concave from above downward. For articulation of the lateral malleolus, its interior half is continuous above with the trochlea and in front of it is a rough depression for the attachment of the interior tallofibular ligament between the posterior half of the lateral border of the trochlea and the posterior part of the base of the fibular articular surface is a triangular facet which comes into contact with the transverse inferior tibial fibular ligament during flexion of the ankle joint. Below the base of this facet is a groove which affords attachment to the posterior tallofibular ligament. The posterior surface is narrow and transverse by a groove running obliquely downward and medialward and transmitting the tendon of the flexor how is this longest. Lateral to the groove is a prominent tubercle, the posterior process to which the posterior tallofibular ligament is attached. This process is sometimes separated from the rest of the tallus and is then known as the os trigonum. Medial to the groove is a second smaller tubercle. The neck, column tally. The neck is directed forward and medialward and comprises the constricted portion of the bone between the body and the oval head. Its upper and medial surfaces are rough for the attachments of ligaments. Its lateral surfaces come cave and is continuous below with a deep groove for the interosseous tallocalconeal ligament. The head, capitally. The head looks forward and medialward its anterior articular or navicular surface is large oval and convex. Its inferior surface has two facets which are best seen in the fresh condition. The medial situated in front of the middle calconeal facet is convex triangular or semi oval in shape and rests on the plantar calconeal navicular ligament. The lateral named the anterior calconeal articular surface is somewhat flattened and articulates with a facet on the upper surface of the anterior part of the calconeus. Articulations. The tallus articulates with four bones tibia, fibula, calconeus and navicular. The cuboid bone, os cubodium. The cuboid bone is placed on the lateral side of the foot in front of the calconeus and behind the fourth and fifth metal tarsal bones it is of a pyramidal shape. Its base being directed medialward. Surfaces. The dorsal surface directed upward and lateralward is rough for the attachment of ligaments. The plantar surface presents in front a deep groove the perineal sulcus which runs obliquely forward and medialward. It lodges the tendon of the perineas lungus and is bounded behind by a prominent ridge to which the long plantar ligament is attached. The ridge ends laterally in an eminence the tuberosity. The surface of which presents an oval facet. On this facet glides a sesamoid bone or cartilage frequently found in the tendon of the perineas lungus. The surface of bone behind the groove is rough for the attachment of the plantar calconeo cuboid ligament. A few fibers of the flexor halusis brevis and a fast aculis from the tendon of the tibialis posterior. The lateral surface presents a deep notch formed by the commencement of the perineal sulcus. The posterior surface is smooth, triangular, and concave or convex. For articulation with the anterior surface of a calconeus its inforo medial angle projects backward as a process which underlies and supports the anterior end of the calconeus. The anterior surface of smaller size but also irregularly triangular is divided by a vertical ridge into two facets. The medial quadrilateral inform articulates with the fourth metatarsal. The lateral larger and more triangular articulates with the fifth. The medial surface is broad irregularly quadrilateral and presents at its middle and upper part a smooth oval facet for articulation with a third uniform and behind this occasionally a smaller facet for articulation with the navicular. It is rough in the rest of its extent for the attachment of strong interosseous ligaments. Articulations. The cuboid articulates with four bones. The calconeus third cuneiform and fourth and fifth metatarsals occasionally with a fifth the navicular. The navicular bone. Os naviculare pedis scaphoid bone. The navicular bone is situated at the medial site of the tarsus between the talus behind and the cuneiform bones in front. Surfaces. The anterior surface is convex from side to side and subdivided by two ridges into three facets for articulation with the three cuneiform bones. The posterior surface is oval concave broader laterally than medially and articulates with a rounded head of the talus. The dorsal surface is convex from side to side and rough for the attachment of ligaments. The plantar surface is irregular and also rough for the attachment of ligaments. The medial surface presents a rounded tuberosity the lower part of which gives attachment to part of the tendon of the tibialis posterior. The lateral surface is rough and irregular for the attachment of ligaments and occasionally presents a small facet for articulation with a cuboid bone articulations. The navicular articulates with four bones the talus and three cuneiforms occasionally with a fifth the cuboid. The first cuneiform bone. Os cuneiform premium. Internal internal cuneiform. The first cuneiform bone is the largest of the three cuneiforms it is situated at the medial side of the foot between the navicular behind and the base of the first metatarsal in front. Surfaces. The medial surface is subcutaneous broad and quadrilateral and its anterior plantar angle is a smooth oval impression into which part of the tendon of the tibialis anterior is inserted and the rest of its extent it is rough for the attachment of ligaments. The lateral surface is concave presenting along its superior and posterior borders a narrow L-shaped surface. The vertical limb and posterior part of the horizontal limb of which articulate with the second cuneiform or the anterior part of the horizontal limb articulates with the second metatarsal bone. The rest of the surface is rough for the attachment of ligaments and part of the tendon of the perineus lungus. The anterior surface kidney-shaped and much larger than the posterior articulates with the first metatarsal bone. The posterior surface is triangular concave and articulates with the most medial and largest of the three facets of the anterior surface of the navicular. The plantar surface is rough and forms the base of the wedge at its back part as a tuberosity the insertion of part of the tendon of the tibialis posterior. It also gives insertion in front to part of the tendon of the tibialis anterior. The dorsal surface is a narrow end of the wedge and is directed upward and lateralward it is rough for the attachment of ligaments, articulations. The first cuneiform articulates with four bones the navicular, second cuneiform and first and second metatarsals. The second cuneiform bone oscuneiformasecondum, middle cuneiform. The second cuneiform bone is smalls of the three is a very regular wedge-like form the thin end being directed downward. It is situated between the other two cuneiforms and articulates with the navicular behind and the second metatarsal in front. Surfaces. The anterior surface triangular in form and narrower than the posterior articulates with the base of the second metatarsal bone. The posterior surface also triangular articulates with the intermediate facet on the anterior surface of the navicular. The medial surface carries an L- shape articular facet running along the superior and posterior borders for articulation of the first cuneiform and is rough in the rest of its extent for the attachment of ligaments. The lateral surface presents a posteriorly a smooth facet for articulation with a third cuneiform bone. The dorsal surface forms the base of the wedge. It is quadrilateral and rough with the attachment of ligaments. The plantar surface, sharp and tuberculated is also rough for the attachment of ligaments and for the insertion of a slip from the tendon of the tibialis posterior articulations. The second cuneiform articulates with four bones the navicular first and third cuneiforms and second metatarsal. The third cuneiform bone lost cuneiforme tertium external cuneiform. The third cuneiform bone intermediate in size between the two proceeding is wedge shaped the base being uppermost. It occupies the center of the front row of the tarsal bones between the second cuneiform medially and cuboid laterally the navicular behind and the third metatarsal in front surfaces. The anterior surface triangular in form articulates with the third metatarsal bone. The posterior surface articulates with a lateral facet on the anterior surface of the navicular and is rough below for the attachment of ligamentous fibers. The menial surface presents an anterior and posterior articular facet separated by a rough depression. The anterior sometimes divided articulates with a lateral side of the base of the second metatarsal bone. The posterior skirts the posterior border and articulates with the second cuneiform. The rough depression gives attachment to an interosseo ligament. The lateral surface also presents two articular facets separated by a rough nonarticular area the anterior facet situated at the superior angle of the bone is small and semi oval in shape and articulates with the medial side of the base of the fourth metatarsal bone. The posterior and larger one is triangular or oval and articulates with the cuboid. The rough nonarticular area serves for the attachment of the interosseous ligament. The three facets for articulation with the three metatarsal bone are continuous with one another. Those for articulation with the second cuneiform and navicular are also continuous but that for articulation the cuboid is usually separate. The dorsal surface is of an oblong form its posterior lateral angle being prolonged backward. The planter surface is a rounded margin and serves for the attachment of part of the tendon of the tibialis posterior part of the flexor hallusis brevis and ligaments articulations. The third cuneiform articulates with six bones the navicular the second cuneiform cuboid and second third and fourth metatarsals. End of section 49 recording by Jennifer Stearns Concordia. Section 50 of Gray's Anatomy Part 1. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org. Recorded by Laurie Ann Walden. Anatomy of the Human Body Part 1 by Henry Gray. The metatarsus. The metatarsus consists of five bones which are numbered from the medial side also metatarsalia one through five. Each presents for examination a body and two extremities. Common characteristics of the metatarsal bones. The body is prismoid in form tapers gradually from the tarsal to the phalangeal extremity and is curved longitudinally so as to be concave below slightly convex above. The base or posterior extremity is wedge shaped articulating proximally with the tarsal bones and by its sides with the contiguous metatarsal bones. Its dorsal and plantar surfaces are rough for the attachments of ligaments. The head or anterior extremity presents a convex articular surface oblong from above downward and extending farther backward below than above. Its sides are flattened and on each is a depression surmounted by a tubercle for ligamentous attachment. Its plantar surface is grooved anteriorly for the passage of the flexor tendons and marked on either side by an articular eminence continuous with the terminal articular surface. Characteristics of the individual metatarsal bones. The first metatarsal bone, os metatarsalia one, metatarsal bone of the great toe. The first metatarsal bone is remarkable for its great thickness and is the shortest of the metatarsal bones. The body is strong and of well marked prismoid form. The base presents as a rule no articular facets on its sides but occasionally on the lateral side there is an oval facet by which it articulates with the second metatarsal. Its proximal articular surface is of large size and kidney shaped. Its circumference is grooved for the torso of metatarsal ligaments and medially gives insertion to part of the tendon of the tibialis anterior. Its plantar angle presents a rough oval prominence for the insertion of the tendon of the perineus longus. The head is large on its plantar surface are two grooved facets on which glide sesamoid bones. The facets are separated by a smooth elevation. The second metatarsal bone, os metatarsalia two. The second metatarsal bone is the longest of the metatarsal bones being prolonged backward into the recess formed by the three cuneiform bones. Its base is broad above, narrow and rough below. It presents four articular surfaces. One behind of a triangular form for articulation with the second cuneiform. One at the upper part of its medial surface for articulation with the first cuneiform and two on its lateral surface an upper and lower separated by a rough non-articular interval. Each of these lateral articular surfaces is divided into two by a vertical ridge. The two anterior facets articulate with the third metatarsal. The two posterior, sometimes continuous, with the third cuneiform. A fifth facet is occasionally present for articulation with the first metatarsal. It is oval in shape and is situated on the medial side of the body near the base. The third metatarsal bone, os metatarsalia three. The third metatarsal bone articulates proximally by means of a triangular smooth surface with the third cuneiform medially by two facets with the second metatarsal and laterally by a single facet with the fourth metatarsal. This last facet is situated at the dorsal angle of the base. The fourth metatarsal bone, os metatarsalia four. The fourth metatarsal bone is smaller in size than the preceding. Its base presents an oblique quadrilateral surface for articulation with the cuboid, a smooth facet on the medial side divided by a ridge into an anterior portion for articulation with the third metatarsal and a posterior portion for articulation with the third cuneiform. On the lateral side, a single facet for articulation with the fifth metatarsal. The fifth metatarsal bone, os metatarsalia five. The fifth metatarsal bone is recognized by a rough eminence, the tuberosity, on the lateral side of its base. The base articulates behind by a triangular surface cut obliquely in a transverse direction with the cuboid and medially with the fourth metatarsal. On the medial part of its dorsal surface is inserted the tendon of the perineus tercius and on the dorsal surface of the tuberosity, that of the perineus brevis. A strong band of the plantar aponeurosis connects the projecting part of the tuberosity with the lateral process of the tuberosity of the calcaneus. The plantar surface of the base is grooved for the tendon of the abductor digitiae quinti and gives origin to the flexor digitiae quinti brevis. Articulations. The base of each metatarsal bone articulates with one or more of the tarsal bones and the head with one of the first row of phalanges. The first metatarsal articulates with the first cuneiform, the second with all three cuneiforms, the third with the third cuneiform, the fourth with the third cuneiform and the cuboid, and the fifth with the cuboid. The phalanges of the foot. Phalanges digitorum pedis. The phalanges of the foot correspond in number and general arrangement with those of the hand. There are two in the great toe and three in each of the other toes. They differ from them however in their size, the bodies being much reduced in length and especially in the first row laterally compressed. First row. The body of each is compressed from side to side, convex above, concave below. The base is concave and the head presents a trochlear surface for articulation with the second phalanx. Second row. The phalanges of the second row are remarkably small and short but rather broader than those of the first row. The ungual phalanges in form resemble those of the fingers but they are smaller and are flattened from above downward. Each presents a broad base for articulation with the corresponding bone of the second row and an expanded distal extremity for the support of the nail and end of the toe. Articulations. In the second, third, fourth and fifth toes the phalanges of the first row articulate behind with the metatarsal bones and in front with the second phalanges which in their turn articulate with the first and third. The ungual phalanges articulate with the second. Osification of the bones of the foot. The tarsal bones are each ossified from a single center accepting the calcaneus which has an epithesis for its posterior extremity. The centers make their appearance in the following order. Calcaneus at the sixth month of fetal life. Talus about the seventh month. Cuboid at the ninth month. Third cuneiform during the first year. First cuneiform in the third year. Second cuneiform and navicular in the fourth year. The epithesis for the posterior extremity of the calcaneus appears at the tenth year and unites with the rest of the bone soon after puberty. The posterior process of the talus is sometimes ossified from a separate center and may remain distinct from the main mass of the bone when it is named the oss trigonome. The metatarsal bones are each ossified from two centers. One for the body and one for the head of the second, third, fourth and fifth metatarsals. One for the body and one for the base of the first metatarsal. Footnote. As was noted in the first metacarpal so in the first metatarsal there is often a second epithesis for its head. End footnote. Ossification commences in the center of the body about the ninth week and extends toward either extremity. The center for the base of the first metatarsal appears about the third year. The centers for the heads of the other bones between the fifth and eighth years. They join the bodies between the 18th and 20th years. The phalanges are each ossified from two centers. One for the body and one for the base. The center for the body appears about the 10th week, that for the base between the fourth and 10th years. It joins the body about the 18th year. End of section 50. Section 51 of Grey's Anatomy Part 1. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org. Recorded by Laurie Ann Walden. Anatomy of the Human Body Part 1 by Henry Gray. Section 51. Comparison of the Bones of the Hand and Foot. The hand and foot are constructed on somewhat similar principles, each consisting of a proximal part, the carpus or the tarsus, a middle portion, the metacarpus or the metatarsus, and a terminal portion, the phalanges. The proximal part consists of a series of more or less cubical bones, which allow a slight amount of gliding on one another, and are chiefly concerned in distributing forces transmitted to or from the bones of the arm or leg. The middle part is made up of slightly movable long bones, which assist the carpus or tarsus in distributing forces, and also give greater breadth for the reception of such forces. The separation of the individual bones from one another allows of the attachments of the interossei, and protects the dorsi palmar and dorsi plantar vascular anastomoses. The terminal portion is the most movable, and its separate elements enjoy a varied range of movements, the chief of which are flexion and extension. The function of the hand and foot are, however, very different, and the general similarity between them is greatly modified to meet these requirements. Thus the foot forms a firm basis of support for the body in the erect posture, and is therefore more solidly built up, and its component parts are less movable on each other than those of the hand. In the case of the phalanges, the difference is readily noticeable. Those of the foot are smaller, and their movements are more limited than those of the hand. Very much more marked is the difference between the metacarpal bone of the thumb and the metatarsal bone of the great toe. The metacarpal bone of the thumb is constructed to permit of great mobility, is directed at an acute angle from that of the index finger, and is capable of a considerable range of movements at its articulation with the carpus. The metatarsal bone of the great toe assists in supporting the weight of the body, is constructed with great solidity, lies parallel with the other metatarsals, and has a very limited degree of mobility. The carpus is small in proportion to the rest of the hand, is placed in a line with the forearm, and forms a transverse arch, the concavity of which constitutes a bed for the flexor tendons and the palmar vessels and nerves. The tarsus forms a considerable part of the foot, and is placed at right angles to the leg, a position which is almost peculiar to man and has relation to his erect posture. In order to allow of their supporting the weight of the body with the least expenditure of material, the tarsus and a part of the metatarsus are constructed in a series of arches, the disposition of which will be considered after the articulations of the foot have been described. Cessamoid bones are small, more or less rounded masses embedded in certain tendons and usually related to joint surfaces. Their functions probably are to modify pressure to diminish friction and occasionally to alter the direction of a muscle pull, that they are not developed to meet certain physical requirements in the adult, is evidenced by the fact that they are present as cartilaginous nodules in the fetus and in greater numbers than in the adult. They must be regarded, according to Thelanius, as integral parts of the skeleton phylogenetically inherited. Physical necessities probably come into play in selecting and in regulating the degree of development of the original cartilaginous nodules. Nevertheless, irregular nodules of bone may appear as the result of intermittent pressure in certain regions, for example, the rider's bone, which is occasionally developed in the adductor muscles of the thigh. Cessamoid bones are invested by the fibrous tissue of the tendons, except on the surfaces in contact with the parts over which they glide, where they present smooth, articular facets. In the upper extremity, the cessamoid bones of the joints are found only on the palmar surface of the hand. Two, of which the medial is the larger, are constant at the metacarpophilangial joint of the thumb. One is frequently present in the corresponding joint of the little finger, and one or two in the same joint of the index finger. Cessamoid bones are also found occasionally at the metacarpophilangial joints of the middle and ring fingers, at the interphilangial joint of the thumb, and at the distal interphilangial joint of the index finger. In the lower extremity, the largest cessamoid bone of the joints is the patella, developed in the tendon of the quadriceps femoris. On the plantar aspect of the foot, two, of which the medial is the larger, are always present at the metatarsal philangial joint of the great toe. One, sometimes at the metatarsal philangial joints of the second and fifth toes. One, occasionally at the corresponding joint of the third and fourth toes. And one, at the interphilangial joint of the great toe. Cessamoid bones, apart from joints, are seldom found in the tendons of the upper limb. One is sometimes seen in the tendon of the biceps brachii opposite the radial tuberosity. They are, however, present in several of the tendons of the lower limb. For example, one in the tendon of the perineus longus, where it glides on the cuboid. One appearing late in life in the tendon of the tibialis anterior opposite the smooth facet of the first cuneiform bone. One in the tendon of the tibialis posterior opposite the medial side of the head of the talus. One in the lateral head of the gastrocnemius, behind the lateral condyle of the femur. And one in the tendon of the psoas major, where it glides over the pubis. Cessamoid bones are found occasionally in the tendon of the gluteus maximus as it passes over the greater trochanter and in the tendons which wind around the medial and lateral malleoli. End of section 51. End of anatomy of the human body part one by Henry Gray.