Human Anatomy and Physiology - I. V. Gayvoronsky 2011

Bone Articulations
Articulations of the Bones of the Lower Extremity

Joint connections of the Pelvic Girdle. The hip bones are connected to each other and to the sacrum through interrupted joints, continuous joints, and a symphysis (hemarthrosis).

The sacroiliac joint, articulatio sacroiliaca, is formed by the auricular surfaces of the sacrum and the ilium. The articular surfaces are covered with fibrocartilage. The sacroiliac joint is a plane joint reinforced by strong sacroiliac ligaments, which is why movements in it are absent.

The Pubic Symphysis, symphysis pubica, lies in the median plane, connects the pubic bones to each other, and Functions as a symphysis (fig. 5.10). Inside the Cartilage (in its superior-posterior section), There is a narrow slit-like cavity that develops during the 1st — 2nd year of life. Minor movements in the pubic symphysis are possible only in women during childbirth. The pubic symphysis is reinforced by two ligaments: superiorly by the superior pubic ligament, and inferiorly by the inferior pubic ligament.

Continuous connections of the hip bone. The iliolumbar ligament extends from the transverse processes of the two lower lumbar vertebrae to the iliac crest.

The sacrotuberous ligament connects the ischial tuberosity to the lateral margin of the sacrum and coccyx.

The sacrospinous ligament stretches from the ischial spine to the lateral margin of the sacrum.

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Fig. 5.10. Bone connections and pelvic dimensions (diagram):

a — superior view: 7 — distantia intercristalis; 2 — distantia interspinosa; 3 — pubic symphysis; 4 — transverse diameter of the pelvic inlet; 5 — true conjugate; 6 — pelvic brim (linea terminalis); 7 — sacroiliac joint; b — lateral view: 7 — greater sciatic foramen; 2 — lesser sciatic foramen; 3 — sacrospinous ligament; 4 — sacrotuberous ligament; 5 — conjugate of the outlet; 6 — pelvic inclination angle; 7 — axis of the pelvis; 8 — true conjugate; 9 — anatomical conjugate; 10 — diagonal conjugate

The obturator membrane covers the obturator foramen of the same name, leaving a small opening near the obturator groove (see fig. 5.11).

The Pelvis as a whole. The hip bones, sacrum, coccyx, and their associated ligamentous apparatus form the pelvis, pelvis. The pelvic bones also serve to connect the trunk to the Free part of the lower limbs.

The pelvis is divided into the greater pelvis, pelvis major, and the lesser pelvis, pelvis minor. They are separated from each other by the terminal line (linea terminalis), which runs on both sides from the sacral promontory along the arcuate line, across the pubic crest to the pubic tubercle, and further along the upper margin of the pubic symphysis.

The walls of the lesser pelvic cavity are formed: posteriorly by the sacrum and the anterior surface of the coccyx; anteriorly by the anterior PARTS OF THE pubic bones and the symphysis; laterally by the inner surface of the hip bone below the terminal line. The obturator foramen located here is almost entirely closed by the membrane of the same name, except for a small opening in the region of the obturator groove.

On the lateral wall of the lesser pelvis are the greater and lesser sciatic foramina. The greater sciatic foramen is bounded by the sacrospinous ligament and the greater sciatic notch. The lesser sciatic foramen is bounded by the sacrospinous and sacrotuberous ligaments, as well as the lesser sciatic notch. Vessels and nerves pass through these openings from the pelvic cavity into the gluteal region.

In the upright position of The Human Body, the pelvis is tilted forward; the plane of the pelvic inlet forms an acute angle with the horizontal plane, constituting the pelvic inclination angle. In women, this angle is 55 — 60°, and in men, 50 — 55°.

Sexual Dimorphism of the pelvis. In women, the pelvis is shorter and wider. The distance between the anterior superior iliac spines and iliac crests is greater because the wings of these bones are flared outward. The sacral promontory projects less forward, which is why the inlet of the male pelvis resembles the shape of a Heart on a playing card; in women, it is more rounded, sometimes even approaching an ellipse. The symphysis of the female pelvis is wider and shorter. The lesser pelvic cavity is more capacious in women, whereas in men it is narrower. The sacrum in women is wider and shorter, the ischial tuberosities are directed outward, making the transverse diameter of the outlet 1 — 2 cm larger. The angle between the inferior rami of the pubic bones (subpubic angle) is 90 — 100° in women and 70 — 75° in men.

Knowledge of the average dimensions of the female pelvis is of great importance in obstetrics for predicting the course of labor. The median anteroposterior dimensions of the lesser pelvis are collectively called conjugates. Typically, the inlet and outlet conjugates are measured. The direct diameter of the pelvic inlet—the distance between the sacral promontory and the upper margin of the pubic symphysis—is called the anatomical conjugate. It measures 11.5 cm. The distance between the sacral promontory and the most posteriorly protruding point of the symphysis is called the true, or gynecological, conjugate; it measures 10.5 — 11.0 cm. The diagonal conjugate is measured between the sacral promontory and the lower margin of the symphysis, and it can be determined in a female patient during a vaginal examination; its value is 12.5 — 13.0 cm. To determine the size of the true conjugate, 2 cm must be subtracted from the length of the diagonal conjugate.

The transverse diameter of the pelvic inlet is measured between the furthest points of the terminal line; it is 13.5 cm. The oblique diameter of the pelvic inlet is the distance between the sacroiliac articulation on one side and the iliopubic eminence on the other; it is 13 cm.

The direct size of the pelvic outlet (exit conjugate) in women is 9 cm and is measured between the tip of the coccyx and the lower margin of the pubic symphysis. During childbirth, the coccyx deviates backward at the sacrococcygeal synchondrosis, increasing this distance by 2.0 — 2.5 cm.

The transverse dimension of the lesser pelvic outlet is 11 cm. It is measured between the inner surfaces of the ischial tuberosities.

The axis of the pelvis, or guiding line, is the curve connecting the midpoints of all conjugates. It runs almost parallel to the anterior surface of the sacrum and indicates the path traversed by the fetal HEAD during labor.

Fig. 5.11. Hip joint:

1 — Joint Capsule; 2 — iliofemoral ligament; 3 — obturator membrane; 4 — pubofemoral ligament; 5 — zona orbicularis; 6 — acetabular labrum; 7 — acetabulum; 8 — ligament of the head of the Femur

In obstetric practice, certain dimensions of the greater pelvis are also of great significance (see fig. 5.10): the distance between the anterior superior iliac spines (distantia interspinosa), which is 25 — 27 cm; the distance between the most distant points of the iliac crests (distantia intercristalis), measuring 27 — 29 cm; and the distance between the greater trochanters of the femurs (distantia intertrochanterica), measuring 31 — 32 cm. To assess the anteroposterior pelvic dimensions, the external conjugate is measured—the distance between the external surface of the pubic symphysis and the spinous process of the 5th lumbar vertebra, which is 20 cm.

Connections of the free lower limb. The hip joint, articulatio coxae, is formed by the acetabulum of the pelvic bone and the head of the femur (Fig. 5.11). The acetabular fossa located in the center is filled with adipose tissue.

The articular capsule attaches along the margin of the acetabular labrum and the medial margin of the femoral neck. Thus, the greater part of the femoral neck lies outside the joint cavity, and fractures of its lateral part are extracapsular, which significantly facilitates Treatment and improves the prognosis of the injury.

Within the thickness of the capsule lies a ligament called the zona orbicularis, which encircles the femoral neck approximately at its midpoint. The joint capsule also contains the fibers of three longitudinally directed ligaments: the iliofemoral, pubofemoral, and ischiofemoral ligaments, which connect the corresponding bones.

The auxiliary elements of the joint include: the acetabular labrum, which deepens the lunate surface of the acetabulum; the transverse acetabular ligament, spanning across the acetabular notch; and the ligament of the head of the femur, which connects the acetabular fossa to the fovea of the femoral head and contains Blood Vessels that supply the femoral head.

The hip joint is a variety of ball-and-socket joint known as a nut-shaped, or cotyloid, joint. Movements are possible around all axes: flexion and extension around the frontal axis, abduction and adduction around the sagittal axis, circumduction around the frontal and sagittal axes, and rotation around the vertical axis.

The knee joint, articulatio genus, is the largest joint in the human body. Three bones participate in its formation: the femur, Tibia, and Patella (Fig. 5.12). The articular surfaces are: the lateral and medial condyles of the femur, the superior articular surface of the tibia, and the articular surface of the patella.

The capsule of the knee joint attaches to the femur 1 cm above the margin of the articular cartilage and anteriorly continues into the suprapatellar bursa, located above the patella between the femur and the tendon of the quadriceps femoris Muscle. On the tibia, the capsule attaches along the margin of the articular surface.

The joint capsule is reinforced by the fibular and tibial collateral ligaments located on either side of the joint, as well as by the patellar ligament, which is the continuation of the quadriceps femoris tendon located below the patella.

Fig. 5.12. The knee joint:

1 — femur; 2 — posterior cruciate ligament; 3 — anterior cruciate ligament; 4 — medial meniscus; 5 — transverse ligament of the knee; 6 — tibial collateral ligament; 7 — patellar ligament; 8 — patella; 9 — tendon of quadriceps femoris muscle; 10 — interosseous membrane of leg; 11 — tibia; 12 — Fibula; 13 — tibiofibular joint; 14 — fibular collateral ligament; 15 — lateral meniscus; 16 — lateral condyle of femur; 17 — patellar surface

The joint possesses many auxiliary elements, such as the patella, menisci, intra-articular ligaments, synovial bursae, and folds.

The lateral and medial menisci partially compensate for the incongruence of the articular surfaces and perform a Shock-absorbing function. The medial meniscus is narrow and crescent-shaped. The lateral meniscus is wider and more oval. The menisci are connected to each other by the transverse ligament of the knee.

The anterior and posterior cruciate ligaments strongly connect the femur and tibia, crossing each other in the shape of the letter "X".

The auxiliary elements of the knee joint also include the alar folds, which contain adipose tissue. They are located below the patella on both sides. The unpaired infrapatellar synovial fold extends from the apex of the patella to the anterior part of the tibia.

The knee joint has several synovial bursae, bursae synoviales, some of which communicate with the joint cavity:

1) the suprapatellar bursa, located between the femur and the tendon of the quadriceps femoris muscle; it communicates with the joint cavity;

2) the deep infrapatellar bursa, situated between the patellar ligament and the tibia;

3) the subcutaneous and subtendinous prepatellar bursae, located in the Connective Tissue on the anterior surface of the knee joint;

4) the muscular bursae, located near the attachment sites of the leg and thigh Muscles in the region of the knee joint.

Fig. 5.13. JOINTS OF THE BONES OF THE leg:

1 — superior articular surface; 2 — tibia; 3 — interosseous membrane of leg; 4 — medial malleolus; 5 — inferior articular surface; 6 — lateral malleolus; 7 — tibiofibular syndesmosis; 8 — fibula; 9 — tibiofibular joint

In terms of its shape, the knee joint is a condylar joint. Flexion and extension occur around the frontal axis. In the flexed position, a small range of leg rotation is possible around the vertical axis.

Connections of the bones of the leg. The bones of the leg are connected to each other by means of both interrupted and continuous joints.

The proximal ends of the leg bones are connected by a discontinuous joint — the tibiofibular joint, articulatio tibiofibularis (Fig. 5.13), which is flat and has limited mobility. The distal ends of the leg bones are connected by the tibiofibular syndesmosis, formed by short ligaments that connect the fibular notch of the tibia and the lateral malleolus of the fibula. A strong fibrous plate, the interosseous membrane, connects both bones almost along their entire length.

Connections of the Bones of the FOOT. The connections of the bones of the foot can be divided into four groups:

1) connections between the bones of the foot and the bones of the leg — the ankle joint;

2) connections between the Tarsal Bones;

3) connections between the tarsal and Metatarsal Bones;

4) connections of the bones of the toes.

The ankle (supra-talar) joint, articulatio talocruralis, is formed by both leg bones and the talus (Fig. 5.14). The pulley of the talus is gripped on the sides by the lateral and medial malleoli.

The joint capsule is attached along the margin of the articular surfaces. On the medial side, it is reinforced by the medial (deltoid) ligament. On the lateral side, the joint capsule is reinforced by three ligaments: the anterior and posterior talofibular ligaments, as well as the calcaneofibular ligament, which connect the respective bones.

Fig. 5.14. Connections of the bones of the foot:

1 — tibia; 2 — interosseous membrane of the leg; 3 — fibula; 4 — ankle joint; 5 — talocalcaneonavicular joint; 6 — navicular bone; 7 — calcaneocuboid joint; 8 — tarsometatarsal joints; 9 — metatarsophalangeal joints; 10 — interphalangeal joints

In shape, the ankle joint is hinge-like (ginglymus). It allows movements around the frontal axis: plantarflexion and dorsiflexion (extension). Because the posterior part of the talar pulley is narrower, slight side-to-side rocking movements are possible in the ankle joint during maximum plantarflexion. Movements in the ankle joint are combined with movements in the subtalar and talocalcaneonavicular joints.

Tarsal bone connections. These are represented by the following joints: the subtalar, talocalcaneonavicular, calcaneocuboid, and cuneonavicular joints.

The subtalar joint, articulatio subtalaris, is located between the talus and the calcaneus. It is a cylindrical joint that allows minor movements only around the sagittal axis.

The talocalcaneonavicular joint, articulatio talocalcaneonavicularis, is spheroidal in shape and situated between the bones of the same name. The articular cavity is supplemented by cartilage formed along the course of the plantar calcaneonavicular ligament.

The ankle (supra-talar), subtalar, and talocalcaneonavicular joints usually function together, forming a functionally unified foot joint in which the talus acts as a bony disc.

The calcaneocuboid joint, articulatio calcaneocuboidea, is located between the bones of the same name; it is saddle-shaped and has limited mobility.

From a surgical perspective, the calcaneocuboid and talonavicular (part of the talocalcaneonavicular) joints are considered a single joint — the transverse tarsal joint (Chopart's joint). The joint spaces of these articulations lie almost in a single line, which can be used for disarticulation of the foot in severe injuries.

The cuneonavicular joint, articulatio cuneonavicularis, is formed by the navicular and cuneiform bones and is virtually immobile.

The tarsometatarsal joints, articulationes tarsometatarsales, are three flat joints located between the medial cuneiform and the first metatarsal bone; between the intermediate and lateral cuneiform bones and the II and III metatarsal bones; and between the cuboid bone and the IV and V metatarsal bones. Surgically, all three joints are combined into a single joint — Lisfranc's joint, which is also used for disarticulation of the distal part of the foot.

The metatarsophalangeal joints, articulationes metatarsophalangeae, are formed by the heads of the metatarsal bones and the sockets of the bases of the proximal Phalanges. They are spheroidal in shape, reinforced by collateral (side) and plantar ligaments, and secured to one another by the deep transverse metatarsal ligament, which runs horizontally between the heads of the I–V metatarsal bones. This ligament plays a crucial role in forming the transverse metatarsal arch of the foot.

Two sesamoid bones are constantly embedded in the plantar part of the capsule of the I metatarsophalangeal joint, causing it to function as a hinge joint. The joints of the remaining four toes function as ellipsoidal joints. They allow flexion and extension around the frontal axis, abduction and adduction around the sagittal axis, and a small degree of circumduction.

The interphalangeal joints, articulationes interphalangeae, are similar in shape and function to those of the hand. They are classified as hinge joints and are reinforced by collateral and plantar ligaments. Under normal conditions, the proximal phalanges are in a state of dorsiflexion, while the middle ones are in plantarflexion.

As previously mentioned, the foot forms longitudinal (five) and transverse (two) arches. A special role in securing the transverse arches belongs to the deep transverse metatarsal ligament, which connects the metatarsophalangeal joints to each other. The longitudinal arches are reinforced by the long plantar ligament, which runs from the calcaneal tuberosity to the base of each metatarsal bone. These ligaments act as "passive" stabilizers of the foot arches.

Review Questions

1. What Types of bone connections do you know?

2. Characterize continuous bone articulations.

3. Name the main elements of a joint.

4. List the Accessory structures of a joint.

5. How are joints classified by shape? Describe the possible movements within them.

6. Provide a Classification of vertebral joints.

7. List the curvatures of THE Vertebral Column and specify the time of their appearance.

8. What types of rib connections do you know?

9. Describe the Structural Features of the temporomandibular joint.

10. List the joints of the upper extremity. What movements are performed in them?

11. What articulations does the hip bone form?

12. What sexual differences of the pelvis do you know?

13. List the dimensions of the female pelvis.

14. Characterize the joints of the free lower extremity.