Basis of Human Anatomy PDF

# Basis of Human Anatomy ## Introduction ### 1) Anatomical Positions | Position | Description | |---|---| | Anatomical erect | * Body standing erect. <br> * Eyes looking forwards. <br> * Upper limbs hanging by sides. <br> * Palms facing forwards. <br> * Thumbs directed lat. | | Supine | Body lie...

# Basis of Human Anatomy ## Introduction ### 1) Anatomical Positions | Position | Description | |---|---| | Anatomical erect | * Body standing erect. <br> * Eyes looking forwards. <br> * Upper limbs hanging by sides. <br> * Palms facing forwards. <br> * Thumbs directed lat. | | Supine | Body lies on its back | | Prone | Body lies on its face | | Lat. decubitus | Body lies on its side (Rt. or Lt) | | Lithotomy | Body lies on its back, with flexion of hip & knee and abduction of hip joints. | ### 2) Anatomical Planes | Plane | Description | |---|---| | Median (sagittal) | Vertical plane passing in middle body, dividing it longitudinally into equal right and left halves. | | Paramedian | Parallel to median plane. | | Coronal (frontal)| Plane cutting body vertically, into anterior part towards front and posterior part towards back of body. | | Horizontal | Transverse plane running horizontally, cutting body into upper (superior) and lower (inferior) parts. | ### 3) Terms of Position | Term | Description | |---|---| | Anterior (ventral) | Infront (near to front) | | Posterior (dorsal) (retro) | Behind (near to back) | | Superior (upper) (cranial) | Near upper end | | Inferior (lower) (caudal) | Near to lower end | | Median | In middle line or median plane. | | Medial | Near to median plane | | Lateral | Away from median plane | | Proximal | Near to root of limb | | Distal | Away from root of limb. | | Superficial | Towards skin or surface body. | | Internal (inner) | Inside organ or body | | Deep | Away from skin or surface body. | | External (outer) | On surface organ or body | | Peri | Around | ### 4) Terms of Number | Term | Description | |---|---| | Uni / Mono | One | | Bi / Di | Two | | Tri | Three | | Quadri | Four | | Multi / Poly | Many | | Oligo | Little | ## Fascia *Definition: Collection of connective tissue under skin, divided into superficial, deep & internal fasciae. ### Superficial Fascia | Feature | Description | |---|---| | Nature | Loose connective tissue immediately deep to skin allowing skin to move freely on underlying structures. | | Distribution | Contains variable quantity of fat more in females. Fat is abundant in breast, ant. abdominal wall and gluteal region, less in limbs and absent in eyelid, penis and scrotum. | | Functions | 1- Softens and smoothens body surface. <br> 2- Facilitates skin movement on underlying structures. <br> 3- Prevents heat loss (thermal insulator). <br> 4- Conducting medium for nerves, blood vessels and lymphatics supplying the skin. <br> 5- Contains muscles; in face (expression muscles). <br> 6- Contains glands; mammary gland. | ### Deep Fascia | Feature | Description | |---|---| | Nature | Inelastic membrane of compact and regular collagen fibers. | | Distribution | Well defined in limbs, very strong in palm and sole, absent in face and anterior abdominal wall. | | Functions | 1- Formation of broad sheets: surround different groups of muscles, so fix underlying structures in position, give attachment to some muscles and help venous return. <br> 2- Formation of intermuscular septa and interosseous membranes: Separate different groups of muscles with different actions and nerve supply. Also increase surface area for muscle attachment. <br> 3- Formation of retinacula: Thickened localized transverse bands at wrist and ankle to keep tendons in position. <br> 4- Formation of palmar and planter aponeurosis: Thick strong layers to protect vessels, nerves and tendons. <br> 5- Formation of fibrous sheaths around big vessels: Carotid sheath around carotid arteries, internal jugular vein and vagus nerve (in neck).| *Clinical importance: -Knowledge of deep fascia arrangement help to explain infection path when spreading from primary site (infection can spread from mouth floor to larynx). <br> -Fluid accumulation in superficial fascia leads to edema. <br> -Skin mobilization after its incision occurs at superficial fascia plane and skin incision along skin crease heals with minimal scar. ## Skeletal System ### A) Bones *Definition: Hard type of connective tissue forming skeleton. * Functions: 1- Give specific shape and provides central axis. 2- Protect vital organs; skull protects brain, thoracic cage protects heart and lungs. 3- Surface area for muscle attachment and form joints (important part of locomotor system). 4- Support and transmit body weight; vertebral column to bony pelvis, lower limbs, feet and ground. 5- Form blood elements in bone marrow and store calcium. * Classification: A) According to position in body; * Axial skeleton: Skull, mandible, hyoid, sternum, ribs and vertebral column. * Appendicular (peripheral ) skeleton: Bones of upper and lower limbs. B) According to ossification process (process of bone formation); * Intra-membranous ossification: Bones develop directly from connective tissue membrane (mesenchyme). Examples: Skull cap and clavicle. It occurs at one or more ossification sites. * Intra-cartilaginous ossification: Connective tissue membrane (mesenchyme) is changed into cartilage which dissolves and disappears to be replaced by bones. Examples: Skull base, long bones, ribs and vertebrae. C) According to shape; ### Long Bones | Feature | Description | |---|---| | Site | Upper and lower limbs | | Structure | 2 ends (epiphysis) and a shaft (diaphysis). <br> * Epiphysis; <br> Expanded upper and lower ends of long bone. <br> - It has smooth articular surface covered by articular hyaline cartilage. <br> * Diaphysis; <br> - Compact bone tube, with central medullary cavity filled with bone marrow (soft vascular tissue). <br> - Separated from epiphysis by epiphyseal plate of hyaline cartilage, responsible for bone growth in length. <br> - Surrounded by periosteum (fibrous sheath), responsible for bone growth in width. <br> N.B. Metaphysis; Upper and lower parts of diaphysis just below epiphyseal cartilage (most active part of long bone). | | Function | | ### Short Bones | Feature | Description | |---|---| | Site | Carpal bones in hand and tarsal bones in foot. | | Structure | Spongy (cancellous) bone covered by compact bone | ### Irregular Bones | Feature | Description | |---|---| | Site | Bones with projecting processes as vertebrae. | | Structure | Similar in structure to short bones. | ### Flat Bones | Feature | Description | |---|---| | Site | Scapula, ribs and skull cap (roof) bones. | | Structure | 2 plates of compact bone with middle layer of spongy bone. <br> N.B.: In skull bones 2 layers of compact are called outer and inner tables while spongy layer is called diploe. | ### Pneumatic Bones | Feature | Description | |---|---| | Site | Skull bones around nose (frontal and maxillary), containing air cavities (paranasal air sinuses). | | Structure | Contains one air cavity (maxillary sinus) or multiple small cells (mastoid air cells). | ### Sesamoid Bones | Feature | Description | |---|---| | Site | Patella; largest sesamoid bone, embedded in quadriceps femoris tendon infront knee. | | Structure | Small bone nodules embedded in some muscle tendons. | ### Growth of Long Bones #### Growth in width (Periosteum) - *Def.: Fibrous sheath around shaft of long bone. - *Structure: -Outer laver: White fibrous tissue. -Inner layer: Contains osteoblasts and highly vascular. - *Function:-Bone growth in width by osteoblasts. -Periosteal blood vessels supply outer 1/3 of shaft. #### Growth in length (Epiphyseal plate of cartilage) - *Def.: Plate of cartilage between epiphysis and diaphysis of long bone. -*Structure: Hyaline cartilage. -*Function: Bone growth in length by proliferation of its cells. When bone becomes mature, it stops division and ossifies resulting in fusion between epiphysis and diaphysis under hormonal control and 2 years earlier in females. It ossifies at one end 2-3 years earlier than the other end which is called the growing end. ### Arterial supply of long bones | Location | Description | |---|---| | Nutrient artery | -Enters shaft at its middle through oblique nutrient foramen and runs away from growing end. <br> -Reaches medullary cavity dividing into ascending and descending branches directed towards upper and lower metaphysis. <br> -Supplies inner 2/3 of bone thickness and bone marrow. | | Metaphyseal arteries | -Enter through minute foramina to supply metaphysis. <br> -Anastomose with nutrient A. and with epiphyseal arteries after ossification of epiphyseal cartilage. | | Epiphyseal arteries | -Many arteries supplying epiphysis. <br> -Anastomose with metaphyseal arteries after ossification of epiphyseal cartilage. | | Periosteal arteries | -Arise from deep layer of periosteum and anastomose with other arteries. <br> -Supply outer 1/3 shaft. |