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Home , Appendicular skeleton, Axial skeleton, Fabella, Hyoid bone

Dr. Sangeeta S Kotrannavar Assistant Professor, Dept. of Anatomy USM-KLE IMP, Belagavi

 Describe the general features of  State the classification and general features of cartilage  List the functions of  Compare between lamellar and non‐lamellar bone  Compare between spongy and compact bone  Describe the parts of long bone  Describe the blood supply of long bone  Describe the classification of  Differentiate between axial and appendicular  Describe the attachments and the arrangements of fibres of  Define prime movers, antagonists, synergists,fixators with examples  Describe the innervation of skeletal muscle  Define motor unit Bones &  HYALINE CARTILAGE  ELASTIC CARTILAGE  FIBRO CARTILAGE

4  Cartilage is a strong, flexible and semi-rigid . It can withstand compression forces, and yet it can bend

 Contains cells and extracellular components.

 Cartilage support regions of the body that require flexibility

 Avascular- nourished by diffusion

 Non nervous structure

 It serves as a precursor or model for the embryonic development and subsequent growth of many long bones

 Poor regeneration capacity  Cells - mesenchymal cells, chondroblasts and chondrocytes.

 Fibres - type II collagen and elastic fibers - provide cartilage with tensile strength and elasticity respectively.

 Abundant extracellular matrix  Glycosaminoglycans(GAG) -chondroitin sulfates, keratin sulfate, hyaluronic acid.  Proteoglycans  60-80% water Form a firm gel which is rubbery, and provides resilience to cartilage  Usually surrounded by perichondrium (peri = around), except articular cartilage and fibro cartilage.

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Hyaline cartilage 7

 Bone is highly vascular  Living  Rigid  specialized mineralized connective tissue  composed of cells embedded in matrix.

 Support-bones forms structural framework of body  Protection - of internal organs like brain, heart &  Mineral homeostasis - bone is a storehouse of calcium and phosphorus  Blood cell production - takes place in the .  Bears body weight - It can withstand compression forces  Lever for muscular actions - provide attachment sites for muscles.  Resonance of sound - with the help of air sinuses  Assisting movement

 Compact bone  Dense outer layer  Limited to cortices,  Important in providing strength Cancellous/ spongy bone  Internal sponge like meshwork  Consisting of trabeculae  Gives additional strength to bone Medullary cavity  Lined by endosteum

 Periosteum  Double layered membrane covering outer surface of bone  Outer fibrous layer  Inner osteogenic layer  Anchored through sharpey’s fibers  rich in nerve supply Protects bone, receives attachments  Endosteum  Lines medullary cavity in long bone & marrow spaces in spongy bone Osteogenic layer - osteoblasts and osteoclasts

= 80  bones -22  - 26  thoracic cage- 25  -6  -1

= 126  upper limbs - 64  lower limbs - 62

 Total number of bones = 206

1) Axial skeleton  skull (cranium and facial bones)  hyoid bone (anchors and muscles associated with )  vertebral column (vertebrae and disks)  thoracic cage ( and )

2) Appendicular skeleton  pectoral girdle ( and scapulae)  upper limbs  pelvic girdle ( bones, , )  lower limbs

 Cranial bones =  Cranial bones = 8 cranium  Frontal  Enclose and protect  Occipital brain  Sphenoid  Attachments for  Ethmoid + muscles  Parietal (2)  Bones are joined by  Temporal (2) sutures  Contains air sinuses

 Facial bones =framework of •Facial bones face = 14  Form cavities for sense organs .  Opening for air + food . passage . (2)  Hold teeth . Zygomatic (2)  Anchor face muscles . Nasal (2)  Bones are joined by . Lacrimal (2) sutures . Palatine (2)  Only the mandible has . Inf. Nasal freely movable Conchae(2)

 Fontanelles – fibrous membranes connecting the cranial bones

 Allows the growth of brain

 Vertebral column = 26  - 7  Thoracic - 12  Lumbar - 5  Sacrum (5 fused) - 1  coccyx (4 fused) - 1

 The vertebral column forms a double C due to two anteriorly convex curvatures in the cervical and lumbar regions.  Ribs   Sternum  Costal cartilages

 True ribs : are directly attached to the sternum (first seven pairs)  False ribs : are joined to above cartilage (8th, 9th & 10th )  Floating ribs : not attached to sternum (11th &12th )

 Protects vital organs, heart & lungs

 The only bone that does not articulate with another bone  Serves as a moveable base for the tongue, and other muscle attachments

 Composed of two bones   These bones allow the to have exceptionally free movement

or Brachium  Forearm or Antebrachium  & includes:  Wrist: carpus -8  Palm: metacarpus- 5  Fingers: phalanges - 14

 Proximal row 1. Scaphoid 2. Lunate 3. Triquetral 4. Pisiform

 Distal row 1. 2. Trapezoid 3. Capitate 4. Hamate (Latreal to medial side) She Looks Too Pretty Try To Catch Her Thumb= pollex  Made up of the paired hip bones  “Bony ” is basin-like structure: hip bones plus the axial sacrum and coccyx  Is strongly attached to axial skeleton (sacrum)  Has deep sockets  More stable than pectoral (shoulder) girdle  Less freedom of movement  Thigh:  Knee:  Leg (lower leg)  (medial side)  (lateral side)

: 7 tarsal bones  5 metatarsals  14 phalanges  Great toe is hallux  Talus  : heel bone  Navicular  Cuboid  3 cunieforms (medial, intermediate and lateral)

 On the basis of Shape

 On the basis of development

 On the basis of structure

1. Long- bones are longer than width  Typical - Shaft & two ends / epiphysis (bones of limbs)  Short long bones – single epiphysis (metacarpal, metatarsal)  Modified long bone – mostly ossifies in membrane & no medullary cavity

2. Short- usually cuboidal in shape (wrist, ankle)

3. Flat- flat, curved (skull, Sternum) consists of 2 plates of compact bones with middle spongy (diploe)

4. Irregular- odd shapes (vertebrae, pelvis)

5. Pneumatic- contains air spaces, ex. maxillary 6. Sesamoid - - formed in the after birth - no periosteum - ex. Patella, pisiform, , ect. 7. Accessory- - developed from extra centres. - ex. Sutural bones

1. Membrane bones: - Bone develops from a fibrous membrane - Intramembranous ossification - Ex. Bones of vault of skull

2. cartilaginous bones: - bone formed by replacing hyaline cartilage - Endochondral / cartilaginous ossification - Ex. Bones of limbs, thoracic cage

3. Membrano- cartilaginous : - Ossify partly in membrane & partly in cartilage - Ex. Clavicle, mandible  Compact bone – Forms the dense shell of bones – Has Haversian systems – Outer surface lined by periosteum – Inner surface lined by endosteum  Cancellous/spongy – Found in ends of bone – No Haversian systems – Surface lined by endosteum

 Immature/spongy/non  Mature/compact / lamellar/woven / lamellar  Is secondary bone created cancellous by remodeling of woven  Is characterized by haphazard bone. organization of collagen fibers  It is highly organized in concentric sheets  mechanically weak. (lamellae)  Low mineral content  mechanically strong.  Present in fetal & growing  High mineral content bones  Present in adult bone

Woven bone

Bone marrow  Diaphysis

 Epiphysis

 Metaphysis

 Epiphysial plate of cartilage

 Bone marrow cavity

Diaphysis-  Ossify from primary centre.  Develops first in early fetal life in the hyaline cartilage model of the future bone Epiphysis-  ossify from secondary centre  Usually formed after birth.  4 Types-Pressure Traction Atavistic Abrrant  law of union of epiphysis  Metaphysis  Most actively growing area of bone.  Vascular zone of growing bone  Epiphysial plate of cartilage  Responsible for growth of long bone  Bone marrow cavity  Two main types: red & yellow.  Yellow marrow - fatty connective tissue and fills the marrow cavity.  The red marrow of some bones is an important site for blood cell production

 Nutrient artery- supplies bone marrow & inner two third of compact bone  Metaphyseal arteries-arising from the anastomosis around joint  Epiphyseal arteries  Periosteal arteries

 Deficiency of calcium in bones in old age leads to osteoporosis, The bones on X-rays examination do not reveal enough trabeculae.  Bone marrow biopsy: Bone marrow can be taken either from manubrium sterni or iliac crest in various clinical conditions  – small rounded projection  – rounded articular projection  Epicondyle – raised area above a condyle  Spine – sharp, slender projection  Process – any bony prominence  Head – bony expansion carried on a narrow neck  Facet – smooth, nearly flat articular surface  Ramus – arm like bar of bone  Meatus – canal-like passage way  Sinus – cavity within a bone  Fossa – shallow, basin-like depression  Groove – furrow  Fissure – narrow, slit-like opening  Foramen – round or oval opening through a bone  Tuberosity – large, rounded projection  Trochanter – large, irregularly shaped process

1

Identify ?? 3 2

4  Identify ??  Latin musculus =little mouse (mus)

 Definition  contractile tissue  which brings about movements Two ends  Origin  from where muscle arise  remains fixed during contraction

 Insertion  terminal end  moves during contraction Two parts

 Fleshy part Fleshy  belly, contractile

 Fibrous part  When cord like, called as tendon; inelastic dense regular fibrous tissue that connects a skeletal muscle to bone  When flattened, called as aponeurosis; sheet like dense fibrous tissue Produce movement  locomotion & manipulation  Help blood to move through veins & food through small intestines Maintain posture Stabilize Body counter & shape Body temp homeostasis  Shivering: movement produces heat energy  By location  Skeletal  Smooth  Cardiac  Fascicular Architecture  Parallel fasciculi  Pennate / oblique fasciculi  Spiral fasciculi  Cruciate fasciculi  By colour  Red muscle  White muscle

 Parallel muscles: are parallel to line of pull  Strap – stenothyroid, rectus abdominis  Quadrate – quadratus lumborum  Fusiform – biceps brchii

Range of movement is more due to increased length of fibers  Pennate muscles/oblique fasciculi – oblique to line of pull  Unipennate  Bipennate  Multipennate  Circumpennate Total force of contraction is increased  Spiral muscles- twisting of fibers  Ex. pectoralis major  Cruciate fasciculi – fibers crosses  Ex. sternocleidomastoid

Red muscle fibers White muscle fiber

Fibers are small in Fibers are wider diameter Abundant myoglobin Less myoglobin

Mitochondria plenty Fewer mitochondria

Can maintain sustained Faster contraction contraction Does not fatigue easily Fatigues easily

Eg;postural muscles, Eg;occular muscles, muscles of trunk, soleus hamstring and muscles etc. gastrocnemius muscles

 Most movements are coordinated by several skeletal muscles acting in groups rather than individually, and most skeletal muscles are arranged in opposing pairs at joints, are  extensor, flexor  abductor, adductor  elevator (= lifter), depressor  supinator, pronator  constrictor, dilator  Prime movers  Antagonists  Synergists  Fixators  A muscle that causes a desired action is referred to as the prime mover (agonist).  Ex. Flexion of forearm at elbow joint. In this instance, the biceps brachii is the prime mover

 These muscles oppose prime mover. They help the prime mover by active relaxation to perform smooth act.  Regulated by via stretch reflex  Ex. Flexion of forearm at elbow joint. Simultaneously with the contraction of the biceps brachii, another muscle is relaxing i e triceps brachii serves as antagonist  You should not assume, however, that the biceps brachii is always the prime mover and the triceps brachii is always the antagonist. For example, when extending the forearm at the elbow, the triceps brachii serves as the prime mover and the biceps brachii functions as the antagonist; their roles are reversed.  When muscle cross more than one joint, synergists prevent undesired movement at intermediate joints.  For example, Flexion of forearm at elbow joint brachioradials & brachialis are synergist muscle  Fixators are group of muscles which stabilize the proximal joint of limb, so that desired movement at distal joint may occur at fixed base.  which stabilize the origin of the prime mover so that the prime mover can act more efficiently.  For example, during flexion of forearm at elbow joint, scapula is firmly hold by fixators like rhomboideus major, rhomboideus minor.

 Motor fibers (60%)  Myelinated Alpha efferent - supply extrafusal muscle fibers –produces contraction  Myelinated Gamma efferent - supply intratrafusal muscle fibers –maintains muscle tone  Unmyelinated sym. Fibers – vasomotor to vessels  Sensory fibers (40%)  Muscle spindles.  Initiation of proprioceptive impulses required for control & regulation of muscular activity  Convey sensations of pain, tension, position and degree of contraction of muscle fibres.  Autonomic – supply smooth muscles of blood vessels within muscle  Sympathetic, Vasoconstrictor