Long bones

Morphology of long bones, their formation and Identification

1. JHARKHAND RAKSHA SHAKTI UNIVERSITY ( Established by State Government and recognised by UGC ) MEURS ’ Road , Near SKIPA ,Ranchi-834008 By Mr. Ayush Kumar Department of Forensic Science Morphology of Long bones

2. B O N E Bone is a calcified, living, connective tissue that forms the majority of skeletal system. It ’ s a Intercellular calcified matrix which consist of collagen fibre. It ’ s Functions is to:- Provide supportive structure to the body. It acts as a protector of internal organs like Brain, Lungs ,Heart etc. Acts as a reservoir in the body. Acts as a lever mechanism in movement. Acts as a container in the body.

3. Type of Bone COMPACT BONE:- – Compact bone is a dense bone tissue composed of osteons, which can resist pressure and shocks and this is how it protects the spongy tissue. – Compact bone forms especially the diaphysis of the Long bones. SPONGY BONE :- – Spongy bones are tissue made of bony compartments separated by cavities filled with bone marrow, blood vessels and nerves. – This gives bones their lightness.

4. Classification of bone according to their shape :- Long bone Short bone Flat bone Irregular bone Sesamoid bone

5. Characteristics of Long Bone :- Long bones are longer than they are wide. They reflects the elongated shape rather than the overall size. They consist of a shaft plus two ends and are constructed primarily of compact bone. They may contain substantial amounts of spongy bone. All bones of the limbs are long bones except the patella, wrist and ankle bones. Example of long bones are :- Humerus, Radius, Ulna , Tibia, Fibula , Femur .

6. Parts of long bone Structure of Long Bone

7. EPIPHYSIS:- – Are expanded articular ends, separated from the shaft by the epiphyseal plate ,during bone growth ,composed of a spongy bone surrounded by a thin layer of compact bone . Proximal Epiphysis Enlarged terminal part of the bone which are nearest to the centre of the body . Distal Epiphysis Enlarged terminal part of the bone which are farthest from the centre of the body. METAPHYSIS:- Part of the bone between the epiphysis and the diathesis which contains the connecting cartilage enabling the bone to grow which disappears at adulthood. DIAPHYSIS:- Elongated hollow central portion of the bone located between the metaphysics made of compact tissue encloses the modularly cavity.

8. OSTEON:- – It’s the elementary cylindrical structure of the compact bone that runs parallel to the longest axis of bone which surrounds and opens into Haversian canal. HAVERSIAN CANAL:- – It’s the lengthwise central canal of the osteon which comprise of enclose blood vessels and nerves. VOLKMANN ’ S CANALS:- Perforating canal which is also transverse canals of the compact bone enclosing blood vessels and nerves connecting the Haversian canals with the medullary cavity and the periosteum . MEDULLARY CAVITY:- Cylindrical central cavity of the bone containing the bone marrow also encloses lipid-rich yellow bone marrow.

9. PERIOSTEUM:- – Periosteum is the fibrous membrane rich in blood vessels that envelopes the bone which contributes especially to the bone’s growth in thickness which’s anchored to the bone itself by bits of collagen called Sharpey’s perforating fibres. CONCENTRIC LAMELLAE:- – The bony layers of osteon made of collagen fibres which are arranged concentrically around the Haversian canal and form as the bones grow. ARTICULAR CARTILAGE :- – It’s the smooth resistant elastic tissue covering the terminal part of the bone which facilitates movement and absorbs shocks. BLOOD VESSEL:- – The channel in the bone through which the blood circulates, carrying the nutrients and mineral salts the bone requires. BONE MARROW:- – It’s the soft substance contained in bone cavities, producing blood cells which’s red in children, yellow in the long bones of adults.

10. HUMERUS BONE Humerus Bone Bony landmarks of the distal humerus The proximal aspect of the humerus

11. PROXIMAL LANDMARKS The proximal humerus is marked by a head, anatomical neck, surgical neck, greater and lesser tubercles and intertubercular sulcus. The upper end of the humerus consists of the head . This faces medially, upwards and backwards and is separated from the greater and lesser tubercles by the anatomical neck. The surgical neck runs from just distal to the tubercles to the shaft of the humerus. The axillary nerve and circumflex humeral vessels lie against the bone here. The shaft of the humerus is the site of attachment for various muscles. Cross section views reveal it to be circular proximally and flattened distally. On the lateral side of the humeral shaft is a roughened surface where the deltoid muscle attaches. This is known is as the deltoid tuberosity .

12. The radial (or spiral) groove is a shallow depression that runs diagonally down the posterior surface of the humerus, parallel to the deltoid tuberosity. The radial nerve and profunda brachii artery lie in this groove. The following muscles attach to the humerus along its shaft: Anteriorly – coracobrachialis, deltoid, brachialis, brachioradialis. Posteriorly – medial and lateral heads of the triceps (the spiral groove demarcates their respective origins). The lateral and medial borders of the distal humerus form medial and lateral supraepicondylar ridges.  Also located on the distal portion of the humerus are three depressions, known as the coronoid, radial and olecranon fossae. They accommodate the forearm bones during flexion or extension at the elbow.

13. TIBIA (SHIN BONE)

14. UPPER END It has two end ie. upper and lower end and intervening shaft. It has two condyles ie.Medial and lateral condyle .The medial condyle is oval in shape and lateral condyle is circular and smaller in shape in between these two there is a intercondylar area which is also known as tibial spine. In the centre there is a shallow depressed area and the peripheral area is flattened which is related to lateral Meniscus. The anterior and lateral surface of lateral condyle shows multiple vascular foramina. The lateral surface has flat circular articular facet for the head of fibula and together these two forms superior tibiofibular joint.

15. SHAFT It has three borders and three surface . Anterior border which is most prominent of the three extending from tibialtuberosity to the anterior margin of medial malleolus.It is sinuous and prominent in upper 2/3 but smooth and round below. Medial border extends from medial condyle to the posterior border of medial malleolus. It’s smooth and round above and below but more prominent in center. Lateral / interosseous border is thin and prominent, specially its centre part which extends from Articular facet and below it splits to form a rough fibular notch.

16. LOWER END It is much smaller than upper end having five surfaces ie. anterior, lateral, posterior, medial and inferior Medial surface is prolonged downward as a strong process known as medial malleolus which is subcutaneous and it’s continuation of the medial surface of the shaft. Anterior surface is the continuation of the lateral surface of the Shaft. Lateral surface has a fibular notch. Posterior surface is the continuation of posterior surface of the Shaft and medially it shows a groove. Interior surface is articular and comes in contact with the articular system of the body of talus it’s quadrilateral and smooth.

17. F E M U R B O N E

18. FEMUR is found in the thigh which is the largest bone in the body and is the only bone in the upper leg with spongy bones at both ends and a cavity filled with bone marrow in the shaft. Below the head of the femur is the neck and the greater trochanter which attaches to tendons that connect to the gluteus minimus and the gluteus medius muscle. This is known as an extension of the leg or the hip. Head : articulates with the acetabulum of the pelvis to form the hip joint having a smooth surface covered with articular cartilage. Neck : Connects the head of the femur with the shaft which is a cylindrical, projecting in a superior and medial direction. It is set at an angle of approx. 135 degree to the shaft. Greater trochanter : the most lateral palpable projection of bone that originate from the anterior aspects just lateral to the neck.

19. Lesser trochanter : It’s smaller than the greater trochanter and projects from the posteromedial side of the femur just inferior to the neck shaft junction. Medial and lateral condyles : It’s round areas at the end of the femur. The posterior and inferior surface articulates with the tibia and menisci of the knee, while the anterior surface articulates with the patella. Medial and lateral epicondyles : bony elevation on the non-articular areas of the condyles.

20. ULNA BONE

21. ULNA is one of two bones that give structure to the forearm. The ulna is located on the side of the forearm from the little finger. It joins with the humerus on its larger end to make the elbow joint, and joins with the carpal bones of the hand at its smaller end together with the radius, the ulna enables the wrist joint to rotate. The proximal end of the ulna articulates with the trochlea of the humerus. To enable movement at the elbow joint the ulna has a specialised structure with bony prominences for muscle attachment. Important landmarks of the proximal ulna are the olecranon, coronoid process, trochlear notch, radial notch and the tuberosity of ulna :-

22. Olecranon – a large projection of bone that extends proximally, forming part of trochlear notch. It can be palpated as the ‘tip’ of the elbow. The triceps brachii muscle attaches to its superior surface. Coronoid process – this ridge of bone projects outwards anteriorly, forming part of the trochlear notch. Trochlear notch – formed by the olecranon and coronoid process. It is wrench shaped, and articulates with the trochlea of the humerus. Radial notch – located on the lateral surface of the trochlear notch this area articulates with the head of the radius. Tuberosity of ulna – a roughening immediately distal to the coronoid process. It is where the brachialis muscle attaches. Styloid process – a projection on the lateral head of ulna. The distal end of the ulna is much smaller in diameter than the proximal end. It is mostly unremarkable, terminating in a rounded head, with distal projection – the ulnar styloid process . The head articulates with the ulnar notch of the radius to form the distal radio-ulnar joint.

23. R A D I U S B O N E

24. RADIUS bone is one of the two large bones of the forearm, the other being the ulna which extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna The ulna is shorter and smaller than the radius and is a slightly curved longitudinally prism- shaped long bone. Head of radius is a disk shaped structure, with a concave articulating surface and is thicker medially, where it takes part in the proximal radioulnar joint. Neck is a narrow area of bone, which lies between the radial head and radial tuberosity. Radial tuberosity is a bony projection, which serves as the place of attachment of the biceps brachii muscle. Distal Region of the Radius is the radial shaft expands to form a rectangular end.

25. The lateral side projects distally as the styloid process . In the medial surface, there is a concavity, called the ulnar notch , which articulates with the head of ulna, forming the distal radioulnar joint . The distal surface of the radius has two facets, for articulation with the scaphoid and lunate carpal bones. This makes up the wrist joint .

26. FIBULA BONE

27. FIBULA is the long, thin, lateral bone of the lower leg and is homologous to ulna of the forearm. In Latin , the term fibula means “ pin ” ; therefore the lateral bone of leg is rightly referred to as fibula because it’s a long pin like bone which runs parallel to the tibia or shin bone and plays a significant role in stabilizing the ankle and supporting the muscles of the lower leg. Proximal or Upper end of the fibula includes a head and a neck the upper end is slightly expanded in all directions making an irregular quadrate form Its superior surface bears a circular articular facet directed upward, forward, and medialward, for articulation with a corresponding surface on the lateral condyle of the tibia. On the lateral side is a thick and rough prominence continued behind into a pointed eminence, the apex or styloid process, which projects upward from the posterior part of the head. Immediately below the head, the fibula constricts and the part is referred to as neck of the fibula.

28. The Shaft of the fibula is slim and its shape is moulded by attached muscles and therefore shows considerable variation in its form. It has three borders and three surfaces:- Anterior, Posterior, Interosseous borders & medial, lateral and posterior. Distal or Lower end of the fibula also known as the lateral malleolus and along with the inferior surface of the tibia the tip of the lateral malleolus is 0.5 cm lower than that of the medial malleolus, and its anterior surface is 1.5 cm posterior to that of the medial malleolus. It has four surfaces :- Anterior surface is rough and round and gives connection to the anterior talofibular ligament. A notch at its lower border gives connection to the calcaneofibular ligament. Posterior surface presents a groove, which lodges tendons of peroneus brevis and peroneus longus, the latter being superficial to the former. Medial surface presents a triangular articular surface in front and a depression (malleolar fossa) below and behind it. Lateral surface is triangular and subcutaneous.

29. T H A N K Y O U …