introduction to human skeleton and Osteology of the lower limb

The bones of the lower limb are uniquely adapted to bear the body's weight, provide balance, and allow for a wide range of movements such as walking, running, jumping, and standing. Understanding their structure, location, and function is essential.
In this section, we will explore the major bones that make up the lower limb — from the hip bone and femur, all the way down to the tarsals and phalanges of the foot. By the end, you’ll gain a clear understanding of how these bones work together to form a strong, functional framework for locomotion and posture.

1. HUMAN SKELETON BY ASWANI CLEVIN ASWANI CLEVIN

2. introduction Bones and teeth are the durable remains of a once-living body. skeleton is permeated with nerves and blood vessels. contains clues to our personal story e.g. age, gender, ethnicity, height, health and nutrition status. ASWANI CLEVIN

3. 206 bones of the human skeleton. divided into : axial skeleton includes the skull, vertebral column, ribs, and sternum. appendicular skeleton includes the bones of the upper limb and pectoral girdle, and bones of the lower limb and pelvic girdle. ASWANI CLEVIN

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5. Axial = 80 bones Skull (cephalic region) = 22 bones Vertebral column = 26 bones Ribs and Sternum= 25 bones Auditory ossicles and Hyoid Skull Vertebrae Ribs and Sternum Auditory ossicles Hyoid Cranial = 8 Frontal (1) Occipital (1) Ethmoid (1) Sphenoid (1) Parietal (2) Temporal (2) Facial = 14 Vomer (1) Mandible (1) Maxillae (2) Zygomatic (2) Nasal (2) Nasal Concha(2) Lacrimal (2) Palatine (2) Cervical (7) Thoracic (12) Lumbar (5) Sacrum (1) Coccyx (1) 12 pairs of ribs 1 sternum Auditory ossicles (6) Malleus (2) Incus (2) Stapes (2) Hyoid (1) Appendicular = 126 Upper = 64 Lower = 62 Upper = 64 •Pectoral Girdle • Arms and Legs Lower = 62 • Pelvic girdle • Legs and feet Pectoral girdle Scapula (2) Clavicle (2) Arms and hands Humerus (2) Ulna (2) Radius (2) Carpals (16) Metacarpals (10) Phalanges (28) Pelvic girdle • Coxal (2) Legs and feet • Femur (2) Patella (2) Tibia (2) Fibula (2) Tarsals (14) Metatarsals (10) Phalanges (28) Total of 206 bones of the human body ASWANI CLEVIN

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7. Importance of skeletal anatomy provides point of reference for studying the gross anatomy of other organ systems because many organs are named for their relationships to nearby bones. understanding of how the muscles produce body movements. can serve as landmarks for a health worker in determining: where to give an injection or record a pulse, what to look for in an X-ray how to perform physical therapy and other medical procedures ASWANI CLEVIN

8. Functions of the Skeleton ● Support. ● Movement. ● Protection. Blood cell formation and energy storage. ● Electrolyte balance /Mineral storage. reservoir of calcium and phosphate. ● Acid–base balance. Bone buffers the blood against excessive pH changes ● Detoxification. absorbs heavy metals and other foreign elements from the blood ASWANI CLEVIN

9. Bones and Osseous Tissue Bone is a connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals in a process called mineralization or calcification. consists of cells separated by an extracellular matrix. bone has both organic and inorganic components. organic components:- cells, fibers, and ground substance. inorganic components :- mineral salts that invade the bony matrix. contains a small amount of tissue fluid. ASWANI CLEVIN

10. types of cells in bone tissue They include:- Osteogenic cells are stem cells that differentiate into bone-forming osteoblasts. Osteoblasts are cells that actively produce and secrete the organic components of the bone matrix( osteoid). . Osteocytes Are osteoblasts which completely surrounded by bone matrix and are no longer producing new osteoid. ASWANI CLEVIN

11. Bones classification According to shape:- ASWANI CLEVIN

12. Anatomical Features of Bones(bone markings) ASWANI CLEVIN

13. Term Description and Example Canal A tubular passage or tunnel in a bone (auditory canal of the skull) Condyle A rounded knob (occipital condyles of the skull) Crest A narrow ridge (iliac crest of the pelvis) Epicondyle A flare superior to a condyle (medial epicondyle of the femur) Facet A smooth joint surface that is flat or only slightly concave or convex (articular facets of the vertebrae) Fissure A slit through a bone (orbital fissures behind the eye) foramen A hole through a bone, usually round (foramen magnum of the skull) Fossa A shallow, broad, or elongated basin ( infraspinous fossa of the scapula) Line ( linea ) A raised, elongated ridge (nuchal lines of the skull) meatus A canal (external acoustic meatus of the temporal bone) process Any bony prominence (mastoid process of the skull) Protuberance A bony outgrowth or protruding part (mental protuberance of the chin) Sinus A cavity within a bone (frontal sinus of the skull) Spine A sharp, slender, or narrow process (spine of the scapula) Sulcus A groove for a tendon, nerve, or blood vessel ( intertubercular sulcus of the humerus ) Tubercle A small, rounded process (greater tubercle of the humerus ) tuberosity A rough surface ( tibial tuberosity) ASWANI CLEVIN

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15. THE PELVIC GIRDLE AND LOWER LIMB ASWANI CLEVIN

16. objectives identify and describe the features of the pelvic girdle, femur, patella, tibia, fibula, and bones of the foot compare the anatomy of the male and female pelvic girdles explain the functional significance of the differences between the male and female pelvis. ASWANI CLEVIN

17. PELVIC GIRDLE consist of 2 hip ( coxal ) bones supports the trunk on the lower limbs ASWANI CLEVIN

18. hip bones have three distinctive features that serve as landmarks:. iliac crest (superior crest of the hip) acetabulum (hip); obturator foramen. formed by fusion of three bones called ilium, Ischium & pubis ASWANI CLEVIN

19. The ilium large, flaring bone that forms the superior region of the hip bone . consists of an inferior body and superior wing like ala. thickened superior margin of the ala is iliac crest . Each iliac crest ends: anteriorly in a blunt anterior superior iliac spine(ASIS) posteriorly in a sharp posterior superior iliac spine . ASWANI CLEVIN

20. Located inferior to these superior iliac spines are the anterior and posterior inferior iliac spines. Posteriorly, just inferior to the posterior inferior iliac spine, it forms greater sciatic notch . broad postero -lateral (gluteal) surface is crossed by three ridges/gluteal lines: posterior, anterior & inferior. ASWANI CLEVIN

21. internal surface of iliac ala is concave called iliac fossa . Posterior to this fossa lies a roughened auricular surface, which articulates with sacrum, forming sacroiliac joint . Running anteriorly and inferiorly from the auricular surface is a robust ridge called the arcuate line which helps define the superior boundary of the true pelvis. ASWANI CLEVIN

22. The ischium forms the infero -posterior portion of the hip bone . ramus of ischium joins inferior ramus of pubis anteriorly . thicker superior body and thinner inferior ramus. prominent triangular ischial spine lies posterior to the acetabulum and projects medially. attachment point for sacrospinous ligament from the sacrum and coccyx ASWANI CLEVIN

23. inferior to the ischial spine is the lesser sciatic notch , inferior surface of ischial body is ischial tuberosity ( rough and thickened) . an area of attachment of hamstring muscles A massive sacrotuberous ligament runs from the sacrum to each ischial tuberosity holding the pelvis together. ASWANI CLEVIN

24. The pubis forms anterior region of hip bone. lies horizontally, and bladder rests upon it . Inverted V-shaped pubic arch/subpubic angle formed with superior and inferior rami extending from a flat body laterally. inferior ramus joins to ischial ramus, superior ramus joins with bodies of ischium and ilium. lateral end of the pubic crest is pubic tubercle , attachment point for inguinal ligament.

25. pectineal line thin ridge lying along the superior pubic ramus, forms anterior portion of the pelvic brim. body lies medially, and its anterior border is thickened to form a pubic crest . obturator foramen occurs between the pubis and ischium bodies of two pubic bones are joined In the midline by a fibrocartilage inter-pubic disc forming pubic symphysis joint.

26. Male and Female Pelvic Structure major differences between typical male and female pelvis are consistent hence can determine the sex of a skeleton with 90% certainty by examining the pelvis. female pelvis is adapted for childbearing It tends to be wider, shallower, and lighter than that of a male providing more room in the true pelvis, which must be wide enough for an infant’s head to pass during birth. ASWANI CLEVIN

27. Comparison of the Male and Female Pelvis Feature Male Female General appearance More massive; rougher; heavier processes Less massive; smoother; more delicate processes Pelvic inlet Heart-shaped Round or oval Pelvic outlet Smaller Larger Pubic symphysis Taller Shorter Greater sciatic notch Narrower Wider Body of pubis More triangular More rectangular Obturator foramen Rounder More oval to triangular Acetabulum Larger, faces more laterally Smaller, faces slightly anteriorly Sacrum Narrower and deeper Wider and shallower Coccyx Less movable; more vertical More movable; tilted posteriorly Subpubic angle Wider Narrower, usually 90° or less usually greater than 100° Tilt Upper end of pelvis relatively vertical Upper end of pelvis tilted forward Depth of greater pelvis Deeper; ilium projects farther above sacroiliac joint Shallower; ilium does not project as far above sacroiliac joint Width of greater pelvis Hips less flared; anterior superior spines closer together Hips more flared; anterior superior spines farther apart ASWANI CLEVIN

28. LOWER LIMB number and arrangement is similar to upper limb. adapted for weight bearing and locomotion and are therefore shaped and articulated differently. divided into four regions with 30 bones per limb: femoral region/thigh. crural region/leg proper. tarsal region/ankle. pedal region /foot .

29. Femur longest and strongest bone of the body, measuring about one-quarter of one’s height. hemispherical head that articulates with the acetabulum of the pelvis forming ball-and-socket joint. ligament extends from the acetabulum to fovea capitis in the head of the femur. Distal to the head is a constricted neck, common site of femoral fractures). beyond the neck are the greater and lesser trochanters (insertions for the powerful muscles of hip). ASWANI CLEVIN

30. trochanters are connected posterior side by a thick oblique ridge of bone intertrochanteric crest anterior side by a more delicate intertrochanteric line. linea aspera posterior ridge on the shaft and at its upper end it forks into a medial spiral line and a lateral gluteal tuberosity . At distal end, it forks into medial and lateral supracondylar lines, which continue down to medial and lateral epicondyles. Distal to epicondyles are two smooth round surfaces medial and lateral condyles , intercondylar fossa. ASWANI CLEVIN

31. anterior side, a smooth medial depression called patellar surface articulates with the patella while on posterior side is a flat or slightly depressed area called popliteal surface. We lock our knees when standing, allowing us to maintain an erect posture with little muscular effort. ASWANI CLEVIN

32. Patella roughly triangular sesamoid bone embedded in the tendon of the knee. It is cartilaginous at birth and ossifies at 3 to 6 years of age. It has; a broad superior base, a pointed inferior apex, pair of shallow articular facets on its posterior surface and lateral facet is usually larger than the medial. ASWANI CLEVIN

33. THE LEG two bones thick strong tibia (medial) & slender fibula (lateral). articulate both proximally & distally. interosseous membrane connects the tibia and fibula along their entire length. tibia articulates with the femur to form knee joint, and with talus bone at ankle joint. fibula, does not contribute to the knee joint and helps in stabilizing ankle joint. ASWANI CLEVIN

34. Tibia only weight-bearing bone of the crural region. Its broad superior head has two fairly flat articular surfaces, the medial and lateral condyles , separated by a ridge called the intercondylar eminence. The condyles of the tibia articulate with those of the femur. ASWANI CLEVIN

35. tibial tuberosity ; rough anterior surface of the tibia palpated just below the patella. Distal to this, the shaft has a sharply angular anterior border, which can be palpated in the shin region. medial malleolus is part of the tibia, and the lateral malleolus is part of the fibula.

36. Fibula slender lateral helps to stabilize the ankle. does not bear any of body’s weight; thicker and broader at its proximal end, the head, than at the distal end. point of the head is the apex . distal expansion is lateral malleolus. joined by shorter ligaments at the superior and inferior ends where the head and apex contact the tibia.

37. THE ANKLE AND FOOT skeleton of foot includes; tarsus, metatarsus & phalanges bones. Functions of foot: supports the weight of the body, acts as a lever to propel the body forward during walking or running.

38. Tarsus makes up the posterior half of the foot and contains seven bones called tarsals The weight of the body is carried primarily by the two largest, most posterior tarsal bones: talus ( “ankle”), which articulates with the tibia and fibula superiorly, The tibia articulates with the talus at the trochlea of the talus . Inferiorly, the talus articulates with the calcaneus 2. strong calcaneus (“heel bone”), which forms the heel of the foot. The thick tendon of the calf muscles attaches to the posterior surface of the calcaneus . The part of the calcaneus that touches the ground is the calcaneal tuberosity , the medial, shelfl ike projection is the sustentaculum tali or talar shelf. lateral cuboid 4. medial navicular 5. cuneiforms ASWANI CLEVIN

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40. Metatarsus consists of five small long bones called metatarsals numbered 1 to 5 beginning on the medial side of the foot . first metatarsal at the base of the big toe is the largest, and it plays an important role in supporting the weight of the body. metatarsals are more nearly parallel to one another than are the metacarpals in the palm. ASWANI CLEVIN

41. Phalanges of the Toes 14 phalanges of the toes are smaller than those of fingers. general structure and arrangement are the same: three phalanges in each digit except the great toe which has only two phalanges. are named proximal, middle, and distal phalanges.

42. Arches of the Foot The foot has three arches: medial longitudinal arches lateral longitudinal arches transverse arch. These arches are maintained by: interlocking shapes of the foot bones strong ligaments, pull of some tendons during muscle activity; ligaments and tendons also provide resilience. ASWANI CLEVIN

43. medial longitudinal arch curves well above the ground. The talus, near the talonavicular joint, is the keystone of this arch, which originates at the calcaneus, rises to the talus, and then descends to the three medial metatarsals. lateral longitudinal arch is very low. It elevates the lateral edge of the foot just enough to redistribute some of the body weight to the calcaneus and some to the head of the fifth metatarsal. The cuboid bone is the keystone of this lateral arch. The two longitudinal arches serve as pillars for the transverse arch, transverse arch runs obliquely from one side of the foot to the other following the line of the joints between the tarsals and metatarsals. ASWANI CLEVIN

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