BSC NURSING SEM1 APPLIED ANATOMY UNIT 7 THE MUSCULOSKELETAL SYSTEM
Anatomical positions
Anatomical Positions
The anatomical position is a standardized posture used as a reference in anatomy to describe locations, relationships, and directions of body parts. It ensures consistency and clarity in describing the human body.
Standard Anatomical Position
The person is standing upright.
The head is facing forward, with the eyes looking straight ahead.
The arms are at the sides with the palms facing forward.
The legs are straight, with feet slightly apart and toes pointing forward.
Anatomical Planes
To describe movements and positions, the body is divided into different planes:
Sagittal Plane:
Divides the body into left and right halves.
Movements: Flexion and extension occur in this plane.
Coronal (Frontal) Plane:
Divides the body into anterior (front) and posterior (back) portions.
Movements: Abduction and adduction occur in this plane.
Transverse (Horizontal) Plane:
Divides the body into superior (upper) and inferior (lower) portions.
Movements: Rotation occurs in this plane.
Directional Terms
These terms describe the location of one body part relative to another:
Superior (Cranial):
Toward the head or upper part of the body.
Example: The head is superior to the chest.
Inferior (Caudal):
Away from the head or toward the lower part of the body.
Example: The stomach is inferior to the lungs.
Anterior (Ventral):
Toward the front of the body.
Example: The chest is anterior to the spine.
Posterior (Dorsal):
Toward the back of the body.
Example: The spine is posterior to the heart.
Medial:
Closer to the midline of the body.
Example: The nose is medial to the eyes.
Lateral:
Away from the midline of the body.
Example: The arms are lateral to the chest.
Proximal:
Closer to the origin or attachment point of a limb.
Example: The shoulder is proximal to the hand.
Distal:
Farther from the origin or attachment point of a limb.
Example: The fingers are distal to the elbow.
Superficial:
Toward or near the surface of the body.
Example: The skin is superficial to the muscles.
Deep:
Away from the surface of the body.
Example: The bones are deep to the muscles.
Body Regions
Axial Region:
Includes the head, neck, and trunk.
Appendicular Region:
Includes the limbs (arms and legs).
Body Cavities
Dorsal Cavity:
Contains the brain (cranial cavity) and spinal cord (spinal cavity).
Ventral Cavity:
Divided into the thoracic cavity (heart and lungs) and the abdominopelvic cavity (digestive organs, bladder, reproductive organs).
Bones- Types,
Bones: Types and Overview
Bones are rigid organs that form the skeleton, providing structure, protection, and enabling movement. They are classified based on their shape, structure, and function.
Shape: Complex shapes that do not fit into other categories.
Examples: Vertebrae, Sacrum, Mandible.
Functions:
Protect internal organs.
Provide support and flexibility.
Sesamoid Bones
Shape: Small, round bones embedded in tendons.
Examples: Patella (kneecap).
Functions:
Protect tendons from stress and wear.
Improve mechanical efficiency of tendons.
2. Types of Bones by Structure
Compact Bone (Cortical Bone):
Characteristics: Dense and hard.
Location: Outer layer of all bones.
Functions:
Provides strength and support.
Protects internal structures.
Spongy Bone (Cancellous Bone):
Characteristics: Lattice-like structure, porous.
Location: Found inside bones, particularly in the epiphysis of long bones and flat bones.
Functions:
Reduces bone weight.
Contains red bone marrow for blood cell production.
3. Types of Bone Marrow
Red Bone Marrow:
Found in spongy bones (e.g., hip bones, ribs, skull).
Produces red blood cells, white blood cells, and platelets.
Yellow Bone Marrow:
Found in the medullary cavity of long bones.
Stores fat for energy.
4. Functions of Bones
Support:
Provide a framework for the body.
Protection:
Shield vital organs (e.g., skull protects the brain, ribs protect the heart and lungs).
Movement:
Act as levers for muscles.
Mineral Storage:
Store calcium and phosphorus.
Blood Cell Production:
Red bone marrow produces blood cells.
Fat Storage:
Yellow bone marrow stores adipose tissue.
Hormonal Regulation:
Produce osteocalcin, which helps regulate blood sugar and fat deposition.
5. Microscopic Structure of Bone
Osteon (Haversian System):
The functional unit of compact bone.
Lamellae:
Concentric rings of bone matrix.
Central Canal:
Contains blood vessels and nerves.
Lacunae:
Small spaces containing osteocytes (bone cells).
Canaliculi:
Tiny channels connecting lacunae for nutrient and waste exchange.
BONES structure,
Structure of Bones
Bones are complex structures made up of multiple layers and components that support the body, protect organs, and enable movement. Below is a detailed description of bone structure:
1. Macroscopic Structure of Bone
A. Types of Bone Tissue
Compact Bone (Cortical Bone):
Dense and solid.
Forms the outer layer of all bones.
Provides strength and protection.
Contains osteons (Haversian systems) for nutrient and waste exchange.
Spongy Bone (Cancellous Bone):
Porous and lightweight.
Found at the ends of long bones and in the interior of flat bones.
Contains trabeculae (lattice-like structures) filled with bone marrow.
B. Parts of a Long Bone
Diaphysis:
The central shaft of the bone.
Composed of compact bone surrounding the medullary cavity.
Medullary cavity contains yellow bone marrow (fat storage).
Epiphysis:
The enlarged ends of a long bone.
Made of spongy bone surrounded by a thin layer of compact bone.
Contains red bone marrow (blood cell production) in certain bones.
Metaphysis:
Region between the diaphysis and epiphysis.
Contains the epiphyseal plate (growth plate) in growing bones.
Periosteum:
A tough, fibrous membrane covering the outer surface of the bone.
Contains blood vessels, nerves, and osteoblasts (bone-forming cells).
Functions:
Provides nourishment.
Aids in bone repair and growth.
Serves as an attachment point for tendons and ligaments.
Endosteum:
Thin membrane lining the medullary cavity.
Contains osteoblasts and osteoclasts (bone-resorbing cells).
Articular Cartilage:
Smooth, hyaline cartilage covering the ends of bones at joints.
Reduces friction and absorbs shock.
2. Microscopic Structure of Bone
A. Bone Cells
Osteoblasts:
Bone-forming cells.
Produce the bone matrix, including collagen and calcium salts.
Osteocytes:
Mature bone cells embedded in the bone matrix.
Maintain the bone matrix.
Osteoclasts:
Bone-resorbing cells.
Break down bone tissue to release calcium and phosphorus.
Osteoprogenitor Cells:
Stem cells that differentiate into osteoblasts.
B. Bone Matrix
Organic Components:
Collagen fibers: Provide flexibility and tensile strength.
Inorganic Components:
Hydroxyapatite crystals (calcium and phosphate): Provide hardness and rigidity.
C. Osteon (Haversian System)
Functional unit of compact bone.
Central Canal (Haversian Canal):
Contains blood vessels and nerves.
Lamellae:
Concentric rings of bone matrix around the central canal.
Lacunae:
Small spaces containing osteocytes.
Canaliculi:
Tiny channels connecting lacunae to each other and to the central canal.
Volkmann’s Canals:
Transverse canals that connect central canals to each other.
3. Bone Marrow
Red Bone Marrow:
Found in spongy bone (e.g., pelvis, ribs, sternum).
Produces red blood cells, white blood cells, and platelets.
Yellow Bone Marrow:
Found in the medullary cavity of long bones.
Stores fat for energy.
4. Blood and Nerve Supply
Nutrient Arteries:
Enter through nutrient foramina to supply the bone with oxygen and nutrients.
Veins:
Drain deoxygenated blood from the bone.
Nerves:
Provide sensory innervation to the periosteum and bone marrow.
Functions of Bone
Support: Provides a framework for the body.
Protection: Shields vital organs (e.g., skull protects the brain).
Movement: Serves as levers for muscles.
Mineral Storage: Reservoir for calcium and phosphorus.
Hematopoiesis: Produces blood cells in red bone marrow.
Energy Storage: Stores fat in yellow bone marrow.
growth and ossification
Bone Growth and Ossification
Bone growth and ossification are fundamental processes in skeletal development, remodeling, and repair.
1. Ossification (Osteogenesis)
Ossification is the process of bone formation, which begins during fetal development and continues into adulthood. There are two types of ossification:
A. Intramembranous Ossification
Definition: Bone develops directly from mesenchymal tissue (undifferentiated connective tissue).
Location: Flat bones of the skull, clavicle, and mandible.
Process:
Mesenchymal cells cluster and differentiate into osteoblasts.
Osteoblasts secrete bone matrix (osteoid).
Osteoid calcifies, forming spongy bone.
Compact bone develops on the outer surfaces.
Bone is vascularized, and periosteum forms.
B. Endochondral Ossification
Definition: Bone forms by replacing a hyaline cartilage template.
Location: Most bones of the body, including long bones (e.g., femur, humerus).
Process:
Hyaline cartilage model develops.
A bone collar forms around the diaphysis.
Cartilage in the center calcifies and creates cavities.
Blood vessels invade the cavity, forming the primary ossification center in the diaphysis.
Secondary ossification centers develop in the epiphyses.
Cartilage is replaced by bone, except at the epiphyseal plates and articular cartilage.
2. Bone Growth
Bone growth occurs through two primary mechanisms:
A. Longitudinal Growth (Lengthwise Growth)
Occurs at: Epiphyseal plates (growth plates).
Process:
Cartilage cells divide and expand at the epiphyseal plate.
Older cartilage is replaced by bone tissue.
Growth continues until the epiphyseal plate fuses (around puberty/adolescence), becoming the epiphyseal line.
Hormones Involved:
Growth hormone.
Thyroid hormone.
Sex hormones (estrogen, testosterone).
B. Appositional Growth (Widthwise Growth)
Occurs at: Periosteum and endosteum.
Process:
Osteoblasts in the periosteum lay down new bone on the outer surface.
Osteoclasts in the endosteum resorb bone from the inner surface, preventing excessive thickness.
This process strengthens bones and accommodates growth in diameter.
3. Factors Affecting Bone Growth
Nutrition:
Calcium and phosphorus for bone mineralization.
Vitamin D for calcium absorption.
Vitamin C for collagen synthesis.
Hormones:
Growth hormone: Stimulates growth at the epiphyseal plate.
Thyroxine: Stimulates osteoblast activity.
Sex hormones: Promote rapid growth during puberty and eventual closure of growth plates.
Physical Activity:
Weight-bearing exercises stimulate bone formation and increase density.
Genetics: Determines the potential size and shape of bones.
4. Bone Remodeling
Definition: Continuous process of bone resorption (osteoclast activity) and bone formation (osteoblast activity).
Purpose:
Replace old or damaged bone tissue.
Maintain calcium and phosphate homeostasis.
Adapt to mechanical stress.
Regulated by:
Parathyroid hormone (PTH): Increases calcium release by stimulating osteoclasts.
Calcitonin: Inhibits osteoclasts, promoting calcium deposition in bones.
5. Disorders Related to Growth and Ossification
Rickets (Children) and Osteomalacia (Adults):
Cause: Vitamin D deficiency.
Result: Soft and weak bones.
Osteoporosis:
Cause: Imbalance in bone remodeling (more resorption than formation).
Result: Fragile bones prone to fractures.
Gigantism/Dwarfism:
Cause: Overproduction or deficiency of growth hormone during development.
Key Differences Between Intramembranous and Endochondral Ossification
Feature
Intramembranous Ossification
Endochondral Ossification
Starting Tissue
Mesenchymal tissue
Hyaline cartilage
Location
Flat bones (skull, clavicle)
Long bones (femur, humerus)
Timeline
Begins earlier during fetal development
Begins later in fetal development
Process
Direct formation of bone matrix
Replacement of cartilage with bone
Axial and Appendicular skeleton
Axial and Appendicular Skeleton
The human skeleton is divided into two main components: the axial skeleton and the appendicular skeleton. Together, they provide structure, support, protection, and enable movement.
1. Axial Skeleton
The axial skeleton forms the central core of the body and consists of 80 bones.
Components of the Axial Skeleton
Skull (22 bones):
Protects the brain and supports facial structures.
Cranial bones (8):
Frontal bone (1)
Parietal bones (2)
Temporal bones (2)
Occipital bone (1)
Sphenoid bone (1)
Ethmoid bone (1)
Facial bones (14):
Nasal bones (2)
Maxillae (2)
Zygomatic bones (2)
Mandible (1)
Lacrimal bones (2)
Palatine bones (2)
Inferior nasal conchae (2)
Vomer (1)
Hyoid Bone (1):
U-shaped bone in the neck.
Supports the tongue and aids in swallowing.
Vertebral Column (26 bones):
Protects the spinal cord and provides support for the body.
Facilitates movement by serving as levers for muscles.
Supports the attachment of muscles and tendons.
Provides mobility to the upper and lower limbs.
Comparison of Axial and Appendicular Skeleton
Feature
Axial Skeleton
Appendicular Skeleton
Definition
Central core of the body
Limbs and girdles
Number of Bones
80
126
Main Function
Support and protect vital organs
Facilitate movement
Examples
Skull, vertebral column, rib cage
Arms, legs, pectoral, and pelvic girdles
Clinical Relevance
Fractures:
Axial skeleton fractures (e.g., rib fractures) can endanger vital organs.
Appendicular fractures (e.g., limb bones) can impair mobility.
Osteoporosis:
Commonly affects both axial (vertebrae) and appendicular bones (hip, wrist).
Scoliosis:
Abnormal lateral curvature of the spine (axial skeleton).
Arthritis:
Affects joints, especially in the appendicular skeleton.
Joints- classification
Classification of Joints
Joints, or articulations, are the connections between bones that allow for movement and provide mechanical support. Joints are classified based on structure and function.
1. Classification Based on Structure
Structural classification depends on the type of connective tissue and the presence or absence of a joint cavity.
A. Fibrous Joints
Description: Bones are connected by dense fibrous connective tissue.
Joint cavity: Absent.
Mobility: Little to no movement.
Examples:
Sutures: Found in the skull (e.g., coronal suture).
Syndesmoses: Bones connected by a ligament (e.g., distal tibiofibular joint).
Gomphoses: Peg-in-socket joint (e.g., teeth in their sockets).
B. Cartilaginous Joints
Description: Bones are connected by cartilage.
Joint cavity: Absent.
Mobility: Limited movement.
Examples:
Synchondroses: Bones united by hyaline cartilage (e.g., epiphyseal plate in growing bones, costal cartilage of the first rib and sternum).
Symphyses: Bones united by fibrocartilage (e.g., pubic symphysis, intervertebral discs).
C. Synovial Joints
Description: Bones are separated by a fluid-filled joint cavity.
Joint cavity: Present.
Mobility: Freely movable (diarthrotic).
Examples: Shoulder joint, knee joint, hip joint.
2. Classification Based on Function
Functional classification is based on the degree of movement permitted at the joint.
A. Synarthrosis (Immovable Joints)
Bones are tightly connected with little or no movement.
Examples:
Sutures in the skull.
Gomphoses (teeth sockets).
B. Amphiarthrosis (Slightly Movable Joints)
Limited movement allowed between bones.
Examples:
Symphysis pubis.
Intervertebral joints.
C. Diarthrosis (Freely Movable Joints)
Allow a wide range of movements.
Correspond to synovial joints structurally.
Examples: Shoulder, hip, elbow, knee.
3. Types of Synovial Joints
Synovial joints are further classified based on the type of movement they allow.
Inflammation of joints causing pain and stiffness (e.g., osteoarthritis, rheumatoid arthritis).
Dislocations:
Bones are forced out of their normal alignment in a joint.
Sprains:
Ligaments are stretched or torn around a joint.
Bursitis:
Inflammation of the bursa (fluid-filled sac near synovial joints).
major joints and structure
Major Joints and Their Structure
Joints are essential for body movement and function, and their structure varies depending on the range of motion they allow. Below are the major joints of the human body and their detailed structure:
1. Shoulder Joint (Glenohumeral Joint)
Type: Ball-and-socket joint (Synovial).
Bones Involved:
Humerus: Head of the humerus forms the ball.
Scapula: Glenoid cavity forms the socket.
Clavicle: Provides structural support.
Structure:
Joint Capsule: Surrounds the joint and is reinforced by ligaments.
Dislocations: Occur when bones are forced out of their normal position.
Arthritis: Inflammation of joints leading to pain and stiffness.
Sprains: Overstretching or tearing of ligaments.
Bursitis: Inflammation of bursae around joints.
Types and structure of Muscles
Types and Structure of Muscles
Muscles are specialized tissues responsible for producing movement, maintaining posture, and generating heat. The human body has three primary types of muscles based on structure, function, and location: skeletal, cardiac, and smooth muscles.
1. Types of Muscles
A. Skeletal Muscle
Structure:
Striated (striped appearance under a microscope).
Multinucleated (nuclei located at the periphery of the muscle fiber).
Long, cylindrical fibers.
Location: Attached to bones via tendons.
Control: Voluntary (consciously controlled).
Functions:
Produces movement (e.g., walking, running).
Maintains posture.
Generates heat through contraction (thermogenesis).
The muscles of the head are responsible for facial expressions, mastication (chewing), eye movement, and other specialized functions. These muscles are divided into specific groups based on their function and location.
1. Muscles of Facial Expression
These muscles are located just beneath the skin and are responsible for facial movements such as smiling, frowning, and raising eyebrows. They are primarily innervated by the facial nerve (Cranial Nerve VII).
Muscle
Function
Location
Frontalis
Raises eyebrows, wrinkles forehead
Forehead
Orbicularis oculi
Closes the eyelids (blinking, winking)
Surrounds the eye
Orbicularis oris
Closes and puckers the lips (kissing)
Surrounds the mouth
Zygomaticus major
Elevates the corners of the mouth (smiling)
Cheekbone to mouth corner
Buccinator
Compresses the cheeks (whistling, blowing)
Cheeks
Platysma
Depresses the mandible, tenses neck skin
Neck to lower jaw
Nasalis
Flares nostrils
Nose
Depressor anguli oris
Draws corners of the mouth downward (frowning)
Lower corners of the mouth
2. Muscles of Mastication (Chewing)
These muscles move the mandible for chewing and are innervated by the mandibular branch of the trigeminal nerve (Cranial Nerve V3).
Muscle
Function
Location
Masseter
Elevates the mandible (closes jaw)
Side of the jaw
Temporalis
Elevates and retracts the mandible
Side of the skull (temporal region)
Medial pterygoid
Elevates and protrudes the mandible
Inside of the mandible
Lateral pterygoid
Protrudes and depresses the mandible (side-to-side grinding)
Inside the cheek
3. Extrinsic Muscles of the Eye
These muscles control eye movement and are innervated by the oculomotor nerve (Cranial Nerve III), trochlear nerve (Cranial Nerve IV), and abducens nerve (Cranial Nerve VI).
Muscle
Function
Innervation
Superior rectus
Elevates and adducts the eyeball
Oculomotor nerve (III)
Inferior rectus
Depresses and adducts the eyeball
Oculomotor nerve (III)
Lateral rectus
Abducts the eyeball
Abducens nerve (VI)
Medial rectus
Adducts the eyeball
Oculomotor nerve (III)
Superior oblique
Depresses and abducts the eyeball
Trochlear nerve (IV)
Inferior oblique
Elevates and abducts the eyeball
Oculomotor nerve (III)
4. Muscles of the Tongue
The tongue muscles are divided into intrinsic (change the shape of the tongue) and extrinsic (move the tongue) groups. They are innervated by the hypoglossal nerve (Cranial Nerve XII), except for the palatoglossus, which is innervated by the vagus nerve (Cranial Nerve X).
Muscle
Function
Type
Genioglossus
Protrudes the tongue
Extrinsic
Hyoglossus
Depresses the tongue
Extrinsic
Styloglossus
Retracts and elevates the tongue
Extrinsic
Palatoglossus
Elevates the back of the tongue
Extrinsic
Intrinsic muscles
Change the shape of the tongue (e.g., curling, flattening)
Intrinsic
5. Muscles of the Pharynx
These muscles assist in swallowing and are innervated by the pharyngeal plexus (mainly the vagus nerve).
Muscle
Function
Location
Superior constrictor
Constricts the upper pharynx during swallowing
Upper pharynx
Middle constrictor
Constricts the middle pharynx
Middle pharynx
Inferior constrictor
Constricts the lower pharynx
Lower pharynx
6. Muscles of the Scalp
These muscles control scalp movement and are part of the epicranius.
Muscle
Function
Location
Occipitofrontalis
Raises eyebrows and wrinkles the forehead
Forehead and occipital region
Galea aponeurotica
A tendon connecting the frontal and occipital muscles
Scalp
neck
Muscles of the Neck
The neck muscles play essential roles in supporting the head, facilitating movement, swallowing, and respiration. These muscles are grouped based on their location and function.
1. Classification of Neck Muscles
A. Superficial Neck Muscles
These muscles are located just under the skin and are involved in head and neck movement and facial expressions.
Muscle
Function
Location
Platysma
Tenses the skin of the neck, depresses the mandible
Superficial layer of the anterior neck
Sternocleidomastoid
Rotates the head to the opposite side, flexes the neck
Extends from the sternum and clavicle to the mastoid process
B. Deep Neck Muscles
These muscles are divided into anterior, lateral, and posterior groups, playing roles in flexion, extension, and stabilization of the neck.
1. Anterior Group (Prevertebral Muscles):
Muscle
Function
Location
Longus capitis
Flexes the head and neck
Base of the skull to the cervical vertebrae
Longus colli
Flexes and rotates the neck
Anterior cervical vertebrae
Rectus capitis anterior
Flexes the head
Between atlas and base of the skull
Rectus capitis lateralis
Stabilizes the head laterally
Lateral to the atlas
2. Lateral Group (Scalene Muscles):
Muscle
Function
Location
Anterior scalene
Elevates the first rib, flexes the neck
Between cervical vertebrae and the first rib
Middle scalene
Elevates the first rib, lateral neck flexion
Posterior to the anterior scalene
Posterior scalene
Elevates the second rib, lateral neck flexion
Posterior to the middle scalene
3. Posterior Group:
Muscle
Function
Location
Splenius capitis
Extends and rotates the head
Back of the neck
Semispinalis capitis
Extends the head and neck
Deep to the splenius capitis
C. Infrahyoid (Strap) Muscles
Located below the hyoid bone, these muscles depress the hyoid and larynx during swallowing and speech.
Muscle
Function
Location
Sternohyoid
Depresses the hyoid bone
Extends from the sternum to the hyoid
Omohyoid
Depresses the hyoid bone
Extends from the scapula to the hyoid
Sternothyroid
Depresses the thyroid cartilage
Lies deep to the sternohyoid
Thyrohyoid
Depresses the hyoid bone and elevates the larynx
Extends from the thyroid cartilage to the hyoid
D. Suprahyoid Muscles
Located above the hyoid bone, these muscles elevate the hyoid and aid in swallowing and tongue movement.
Muscle
Function
Location
Digastric
Elevates the hyoid, depresses the mandible
Extends from the mandible to the mastoid
Stylohyoid
Elevates and retracts the hyoid bone
Extends from the styloid process to the hyoid
Mylohyoid
Elevates the floor of the mouth and hyoid bone
Forms the floor of the oral cavity
Geniohyoid
Elevates the hyoid bone
Lies superior to the mylohyoid
2. Functions of the Neck Muscles
Movement of the Head and Neck:
Flexion, extension, lateral flexion, and rotation of the head and neck.
Facilitated by muscles like sternocleidomastoid and scalene muscles.
Swallowing and Speech:
Suprahyoid and infrahyoid muscles move the hyoid bone and larynx.
Respiration:
Scalene muscles assist in elevating the ribs during inspiration.
Stabilization:
Deep neck muscles stabilize the cervical spine and head.
thorax,
Thorax: Structure and Anatomy
The thorax, commonly known as the chest, is a part of the body located between the neck and abdomen. It is a crucial region housing vital organs such as the heart and lungs, protected by the rib cage and associated muscles.
1. Components of the Thorax
A. Thoracic Skeleton
The bony framework of the thorax provides protection and support.
Sternum (Breastbone):
Flat, elongated bone in the anterior thoracic wall.
Divided into three parts:
Manubrium: Upper part; articulates with the clavicles and the first pair of ribs.
Body: Middle and largest part; articulates with ribs 2–7.
Xiphoid Process: Small, cartilaginous structure at the bottom, ossifies with age.
Ribs:
Twelve pairs of curved bones forming the rib cage.
Types:
True Ribs (1–7): Directly attached to the sternum via costal cartilage.
False Ribs (8–10): Indirectly attached to the sternum through the cartilage of the rib above.
Floating Ribs (11–12): Not attached to the sternum.
Functions:
Protect thoracic organs.
Assist in breathing by expanding and contracting.
Thoracic Vertebrae:
Twelve vertebrae (T1–T12) of the spine.
Each vertebra articulates with a pair of ribs.
B. Thoracic Muscles
The muscles of the thorax are involved in respiration and movement.
Intercostal Muscles:
Located between ribs.
Types:
External Intercostal Muscles: Elevate ribs during inspiration.
Internal Intercostal Muscles: Depress ribs during forced expiration.
Innermost Intercostal Muscles: Assist with respiration.
Diaphragm:
Dome-shaped muscle separating the thoracic and abdominal cavities.
Main muscle of respiration.
Function: Contracts during inspiration, increasing thoracic volume.
Accessory Muscles:
Pectoralis Major and Minor: Assist in forced inspiration.
Serratus Anterior: Stabilizes the scapula and assists in breathing.
Scalene Muscles: Elevate the first two ribs during deep inspiration.
C. Thoracic Cavity
The thoracic cavity is the space within the thorax, housing vital organs.
Pleural Cavities:
Two cavities, one for each lung.
Pleura: Double-layered membrane.
Parietal Pleura: Lines the thoracic wall.
Visceral Pleura: Covers the lungs.
Mediastinum:
Central compartment of the thoracic cavity.
Contains:
Heart (within the pericardium).
Major blood vessels (aorta, vena cava).
Trachea and esophagus.
Thymus gland.
Lymph nodes.
2. Organs of the Thorax
A. Heart:
Located in the mediastinum, slightly left of the midline.
Enclosed in the pericardium.
Pumps blood to the body and lungs via arteries and veins.
B. Lungs:
Paired organs responsible for gas exchange.
Divided into lobes:
Right lung: Three lobes (superior, middle, inferior).
Left lung: Two lobes (superior, inferior).
Alveoli in the lungs facilitate oxygen and carbon dioxide exchange.
C. Trachea and Esophagus:
Trachea: Airway conducting air to the lungs.
Esophagus: Tube carrying food from the throat to the stomach.
3. Functions of the Thorax
Protection:
Shields vital organs (heart, lungs, major blood vessels) from external forces.
Respiration:
Facilitates breathing through the expansion and contraction of the thoracic cavity.
Support:
Provides attachment points for muscles involved in respiration and upper limb movement.
Conduit:
Allows passage of structures like the trachea, esophagus, and major blood vessels.
abdomen
Abdomen: Structure and Anatomy
The abdomen is the region of the body between the thorax and pelvis. It contains vital organs involved in digestion, excretion, and other critical functions. The abdominal wall, cavity, and organs work together to support and protect these functions.
1. Boundaries of the Abdomen
Superior Boundary:
Diaphragm separates the abdomen from the thorax.
Inferior Boundary:
Pelvic brim separates the abdomen from the pelvis.
Anterior and Lateral Boundaries:
Formed by the abdominal wall muscles.
Posterior Boundary:
Formed by the vertebral column and associated muscles.
2. Regions of the Abdomen
The abdomen is divided into 9 regions (for clinical purposes) or 4 quadrants (for diagnostic purposes).
A. Nine Abdominal Regions:
Right Hypochondriac: Liver, gallbladder.
Epigastric: Stomach, liver, pancreas.
Left Hypochondriac: Spleen, stomach.
Right Lumbar (Flank): Ascending colon, right kidney.
Umbilical: Small intestine, transverse colon.
Left Lumbar (Flank): Descending colon, left kidney.
The abdominal cavity houses major organs of the digestive, urinary, and reproductive systems.
A. Digestive Organs:
Stomach:
Located in the LUQ.
Breaks down food and begins digestion.
Liver:
Located in the RUQ.
Produces bile, detoxifies blood, and stores nutrients.
Gallbladder:
Stores and concentrates bile.
Lies beneath the liver.
Small Intestine:
Includes the duodenum, jejunum, and ileum.
Responsible for nutrient absorption.
Large Intestine:
Includes the cecum, colon, rectum, and anal canal.
Absorbs water and forms feces.
Pancreas:
Secretes digestive enzymes and hormones like insulin.
B. Urinary Organs:
Kidneys:
Filter blood to form urine.
Located retroperitoneally.
Ureters:
Transport urine from kidneys to the bladder.
Bladder:
Stores urine before excretion.
C. Reproductive Organs:
Ovaries and Uterus (Females):
Located in the lower abdomen/pelvis.
Testes (Males):
Located outside the abdominal cavity.
D. Spleen:
Located in the LUQ.
Part of the lymphatic system; filters blood and fights infection.
5. Blood Supply to the Abdomen
Arteries:
Abdominal Aorta: Supplies oxygenated blood to abdominal organs.
Branches:
Celiac Trunk: Supplies the liver, stomach, and spleen.
Superior Mesenteric Artery: Supplies the small intestine and part of the large intestine.
Inferior Mesenteric Artery: Supplies the distal large intestine.
Veins:
Inferior Vena Cava: Drains deoxygenated blood.
Portal Vein: Carries nutrient-rich blood from the digestive tract to the liver.
6. Functions of the Abdomen
Digestive Functions:
Processes and absorbs nutrients.
Excretes waste products.
Respiratory Assistance:
Abdominal muscles aid in forced expiration.
Protection:
Shields internal organs from trauma.
Posture and Movement:
Abdominal muscles support the spine and facilitate movement.
pelvis,
Pelvis: Structure and Anatomy
The pelvis is a bony structure located at the base of the spine, connecting the trunk to the lower limbs. It plays a critical role in weight-bearing, movement, and protecting vital organs.
1. Components of the Pelvis
The pelvis is divided into the bony pelvis, muscular components, and the pelvic cavity.
A. Bony Pelvis
The bony pelvis is made up of four bones:
Hip Bones (Coxal Bones or Os Coxae):
Each hip bone is formed by the fusion of three bones:
Ilium:
Largest, uppermost part of the hip bone.
Features:
Iliac crest: Superior ridge.
Anterior superior iliac spine (ASIS): Bony projection felt at the front of the hip.
Ischium:
Lower, posterior portion.
Features:
Ischial tuberosity: Supports body weight when sitting.
Pubis:
Anterior portion.
Features:
Pubic symphysis: Fibrocartilaginous joint between the two pubic bones.
Sacrum:
A triangular bone formed by the fusion of five sacral vertebrae.
Articulates with the ilium at the sacroiliac joints.
Coccyx:
Also known as the tailbone.
Formed by the fusion of four small vertebrae.
B. Joints of the Pelvis
Sacroiliac Joint:
Connects the sacrum to the ilium.
Stabilizes the pelvis.
Pubic Symphysis:
Fibrocartilaginous joint between the two pubic bones.
Female: Uterus, ovaries, fallopian tubes, and vagina.
Male: Prostate gland, seminal vesicles, and parts of the vas deferens.
Urinary Organs:
Bladder and urethra.
Digestive Organs:
Rectum and anal canal.
3. Muscles of the Pelvis
Pelvic muscles support the pelvic organs, assist in movement, and control functions like urination and defecation.
A. Pelvic Floor Muscles:
Levator Ani:
Main pelvic floor muscle group.
Includes:
Pubococcygeus
Puborectalis
Iliococcygeus
Functions:
Supports pelvic organs.
Controls continence.
Coccygeus:
Located posteriorly.
Supports pelvic structures.
B. Hip and Thigh Muscles:
Iliopsoas:
Includes the iliacus and psoas major.
Flexes the hip.
Gluteal Muscles:
Includes gluteus maximus, medius, and minimus.
Extend and stabilize the hip.
Obturator Internus and Piriformis:
Rotate the thigh laterally.
4. Functions of the Pelvis
Support and Weight-Bearing:
Transfers body weight from the axial skeleton to the lower limbs.
Protection of Organs:
Encloses and shields the bladder, reproductive organs, and rectum.
Attachment Site for Muscles:
Provides attachment points for muscles involved in movement and posture.
Facilitates Childbirth:
In females, the pelvis is adapted for childbirth with a wider pelvic inlet and outlet.
5. Differences Between Male and Female Pelvis
Feature
Male Pelvis
Female Pelvis
Pelvic Inlet
Narrow and heart-shaped
Wider and oval-shaped
Pelvic Outlet
Smaller
Larger
Iliac Crests
Higher and more upright
Lower and more flared
Pubic Arch
Narrow (less than 90°)
Wider (more than 90°)
Sacrum
Longer, narrower, and more curved
Shorter, wider, and less curved
upper limb and lower limbs
Upper Limb and Lower Limb Anatomy
The upper limbs and lower limbs are essential for movement, strength, and interaction with the environment. They are composed of bones, joints, muscles, nerves, and blood vessels.
Upper Limb Anatomy
1. Bones of the Upper Limb
The bones are divided into four regions:
Shoulder Girdle:
Clavicle (Collarbone): Connects the sternum to the scapula, stabilizing the shoulder.
Scapula (Shoulder Blade): Flat bone that provides attachment for muscles and forms part of the shoulder joint.
Arm (Brachium):
Humerus: The longest bone in the upper limb; forms the shoulder joint proximally and the elbow joint distally.
Forearm (Antebrachium):
Radius: Lateral bone of the forearm (thumb side).
Ulna: Medial bone of the forearm (little finger side).
Hand:
Carpals (Wrist Bones): Eight small bones arranged in two rows.
Metacarpals (Palm Bones): Five long bones.
Phalanges (Finger Bones): 14 bones (3 per finger, 2 for the thumb).
2. Joints of the Upper Limb
Shoulder Joint (Glenohumeral Joint): Ball-and-socket joint allowing a wide range of motion.
Elbow Joint: Hinge joint allowing flexion and extension.
Intrinsic Muscles: Stabilize the foot during walking and running.
4. Nerves of the Lower Limb
Lumbar Plexus: Supplies the anterior thigh.
Major nerve: Femoral Nerve (thigh extensors).
Sacral Plexus: Supplies the posterior thigh, leg, and foot.
Major nerves:
Sciatic Nerve: Largest nerve, splits into tibial and common fibular nerves.
Tibial Nerve: Innervates posterior leg and foot.
Common Fibular Nerve: Innervates anterior and lateral leg.
5. Functions of the Lower Limb
Supporting body weight during standing.
Facilitating locomotion (walking, running).
Maintaining balance and posture.
Comparison of Upper and Lower Limbs
Feature
Upper Limb
Lower Limb
Primary Function
Manipulation and dexterity
Support and locomotion
Largest Bone
Humerus
Femur
Joints
Shoulder (more mobile)
Hip (more stable)
Key Nerve Plexus
Brachial Plexus
Lumbar and Sacral Plexuses
Principal muscles- deltoid
Deltoid Muscle: Anatomy and Function
The deltoid muscle is a large, triangular-shaped muscle that forms the rounded contour of the shoulder. It is one of the most important muscles for arm movement and stabilization of the shoulder joint.
1. Origin and Insertion
Origin (Proximal Attachment):
The deltoid muscle has three parts based on its origin:
Anterior (Clavicular) Part:
Originates from the lateral third of the clavicle.
Middle (Acromial) Part:
Originates from the acromion of the scapula.
Posterior (Spinal) Part:
Originates from the spine of the scapula.
Insertion (Distal Attachment):
All parts of the deltoid muscle insert into the deltoid tuberosity on the lateral aspect of the humerus.
2. Structure
The deltoid is a thick, multipennate muscle. Its fibers are arranged in three distinct parts, which contribute to its versatility in arm movement.
3. Nerve Supply
Axillary Nerve (C5, C6):
Branch of the brachial plexus.
Provides motor innervation to the deltoid muscle.
4. Blood Supply
Posterior Circumflex Humeral Artery (branch of the axillary artery).
Deltoid Branch of the Thoracoacromial Artery.
5. Actions of the Deltoid Muscle
The three parts of the deltoid muscle work together or independently to perform various movements of the shoulder joint:
A. Anterior (Clavicular) Part:
Flexes the arm (moves it forward).
Medially rotates the arm.
B. Middle (Acromial) Part:
Abducts the arm (raises it away from the body).
C. Posterior (Spinal) Part:
Extends the arm (moves it backward).
Laterally rotates the arm.
6. Function in Everyday Activities
Lifting: Middle fibers are active during abduction, such as lifting objects.
Throwing: Anterior fibers help with the forward movement of the arm.
Pulling: Posterior fibers assist in pulling motions.
7. Clinical Relevance
A. Deltoid Injury:
Strains or tears can occur from overuse or trauma.
Symptoms include pain and difficulty lifting the arm.
B. Axillary Nerve Injury:
Damage to the axillary nerve can lead to deltoid muscle paralysis, causing loss of shoulder abduction.
C. Deltoid Muscle Atrophy:
Can occur due to disuse, nerve injury, or conditions like muscular dystrophy.
Leads to a flattened shoulder appearance.
8. Exercises to Strengthen the Deltoid
Overhead Press: Strengthens all parts of the deltoid.
Lateral Raises: Targets the middle fibers.
Front Raises: Focuses on the anterior fibers.
Reverse Flys: Engages the posterior fibers.
biceps,
Biceps Muscle: Anatomy and Function
The biceps brachii, commonly referred to as the biceps, is a prominent muscle of the upper arm. It is responsible for flexing the elbow and supinating the forearm. The term “biceps” means “two heads,” referring to its two points of origin.
1. Origin and Insertion
Origin (Proximal Attachment):
The biceps brachii has two heads:
Long Head:
Originates from the supraglenoid tubercle of the scapula.
Short Head:
Originates from the coracoid process of the scapula.
Insertion (Distal Attachment):
Radial Tuberosity:
Located on the proximal radius.
Bicipital Aponeurosis:
A broad connective tissue sheet blending into the forearm fascia.
2. Structure
The biceps brachii is a fusiform (spindle-shaped) muscle located in the anterior compartment of the upper arm.
3. Nerve Supply
Musculocutaneous Nerve (C5, C6):
A branch of the brachial plexus.
4. Blood Supply
Brachial Artery: Main blood supply to the biceps.
5. Actions of the Biceps Muscle
The biceps brachii performs several important functions:
Flexion of the Elbow:
Bends the forearm toward the upper arm.
Supination of the Forearm:
Rotates the forearm to turn the palm upward.
Weak Flexion of the Shoulder:
Assists in lifting the arm at the shoulder joint.
6. Function in Everyday Activities
Lifting: Biceps flex the elbow while picking up objects.
Turning Keys/Doorknobs: Supination of the forearm is essential.
Pulling: Used in pulling motions like rowing.
7. Clinical Relevance
A. Biceps Tendon Injuries:
Tendonitis:
Inflammation of the biceps tendon, often due to overuse.
Symptoms: Pain in the front of the shoulder or elbow.
Tendon Rupture:
Common in the long head of the biceps.
Symptoms: Sudden “pop” followed by pain and a visible bulge in the upper arm (Popeye deformity).
B. Weakness or Paralysis:
Injury to the musculocutaneous nerve can lead to weakened elbow flexion and supination.
8. Exercises to Strengthen the Biceps
Bicep Curls:
Isolate the biceps for maximum strengthening.
Hammer Curls:
Engage both the biceps and the brachialis (another arm flexor).
Chin-Ups:
Use body weight to strengthen the biceps.
Concentration Curls:
Focus on isolating and engaging the biceps fully.
9. Associated Muscles
Brachialis:
Lies deep to the biceps and assists in elbow flexion.
Coracobrachialis:
Located near the biceps and aids in shoulder flexion.
triceps,
Triceps Muscle: Anatomy and Function
The triceps brachii, commonly known as the triceps, is the primary muscle located in the posterior compartment of the upper arm. Its primary function is the extension of the elbow joint, working as the antagonist to the biceps brachii.
1. Origin and Insertion
Origin (Proximal Attachment):
The triceps has three heads, hence the name “triceps” (tri = three).
Long Head:
Originates from the infraglenoid tubercle of the scapula.
Lateral Head:
Originates from the posterior surface of the humerus, above the radial groove.
Medial Head:
Originates from the posterior surface of the humerus, below the radial groove.
Insertion (Distal Attachment):
Olecranon Process of the Ulna: The common insertion point for all three heads of the triceps.
Antebrachial Fascia: Via a fibrous expansion.
2. Structure
The triceps brachii is a large, fusiform (spindle-shaped) muscle occupying the posterior compartment of the upper arm.
It has three heads (long, lateral, medial) that converge into a single tendon.
3. Nerve Supply
Radial Nerve (C6, C7, C8):
Innervates all three heads of the triceps.
4. Blood Supply
Deep Brachial Artery (Profunda Brachii):
Branch of the brachial artery.
5. Actions of the Triceps Muscle
The triceps is primarily responsible for the following:
Elbow Extension:
Straightens the arm at the elbow joint.
Shoulder Extension (Long Head):
Assists in extending and adducting the arm at the shoulder joint.
6. Function in Everyday Activities
Pushing Motions:
Essential for activities like pushing doors or lifting heavy objects.
Supporting Weight:
Helps stabilize the arm during weight-bearing activities like using crutches.
Throwing and Striking:
Engages during actions like throwing a ball or striking in sports.
7. Clinical Relevance
A. Triceps Tendon Injuries:
Tendonitis:
Inflammation of the triceps tendon, often due to repetitive overuse (e.g., in sports).
Symptoms: Pain at the back of the elbow.
Tendon Rupture:
Rare but can occur due to sudden forceful contraction.
Symptoms: Weakness in elbow extension and a palpable gap near the olecranon.
B. Radial Nerve Injury:
Can impair triceps function, leading to weakened elbow extension and difficulty in weight-bearing tasks.
C. Atrophy:
Muscle wasting due to disuse or nerve damage.
8. Exercises to Strengthen the Triceps
Tricep Dips:
Uses body weight to engage the triceps.
Overhead Tricep Extensions:
Isolates the long head of the triceps.
Close-Grip Push-Ups:
Targets the triceps along with the chest muscles.
Tricep Kickbacks:
Focuses on isolating the triceps during extension.
Skull Crushers (Lying Tricep Extensions):
Strengthens all three heads of the triceps.
9. Associated Muscles
Anconeus:
A small muscle assisting the triceps in elbow extension.
Deltoid and Pectoralis Major:
Work with the long head of the triceps during shoulder extension and stabilization.
Comparison of Triceps and Biceps
Feature
Triceps Brachii
Biceps Brachii
Location
Posterior compartment of the upper arm
Anterior compartment of the upper arm
Primary Action
Elbow extension
Elbow flexion and forearm supination
Nerve Supply
Radial nerve
Musculocutaneous nerve
respiratory,
Respiratory System: Anatomy and Function
The respiratory system is responsible for gas exchange, supplying oxygen to the body and removing carbon dioxide. It consists of both structural and functional components that work together to facilitate breathing.
1. Components of the Respiratory System
The respiratory system is divided into two main parts:
A. Upper Respiratory Tract
Nose and Nasal Cavity:
Filters, warms, and humidifies incoming air.
Contains hair and mucus to trap dust and microorganisms.
Pharynx (Throat):
Passageway for air and food.
Divided into:
Nasopharynx
Oropharynx
Laryngopharynx
Larynx (Voice Box):
Contains vocal cords for sound production.
Epiglottis prevents food from entering the trachea during swallowing.
B. Lower Respiratory Tract
Trachea (Windpipe):
Tube supported by C-shaped cartilage rings.
Conducts air to the bronchi.
Bronchi:
Right and left primary bronchi branch from the trachea.
Further divide into secondary and tertiary bronchi.
Bronchioles:
Small airways without cartilage.
Lead to the alveoli.
Alveoli:
Microscopic air sacs where gas exchange occurs.
Surrounded by capillaries for oxygen and carbon dioxide exchange.
2. Structure of the Lungs
Lobes:
Right Lung: 3 lobes (superior, middle, inferior).
Left Lung: 2 lobes (superior, inferior) to accommodate the heart.
Pleura:
Parietal Pleura: Lines the thoracic cavity.
Visceral Pleura: Covers the lungs.
Pleural Cavity: Fluid-filled space reducing friction during breathing.
Diaphragm:
Dome-shaped muscle separating the thoracic and abdominal cavities.
Main muscle for inspiration.
3. Mechanics of Breathing
A. Inspiration (Inhalation):
Diaphragm contracts and flattens.
External intercostal muscles lift the rib cage.
Thoracic volume increases, creating negative pressure to draw air into the lungs.
B. Expiration (Exhalation):
Diaphragm relaxes and moves upward.
Internal intercostal and abdominal muscles assist in forced exhalation.
Thoracic volume decreases, pushing air out of the lungs.
4. Gas Exchange Process
External Respiration:
Occurs in the alveoli.
Oxygen diffuses from alveoli into blood; carbon dioxide diffuses from blood into alveoli.
Internal Respiration:
Occurs at the tissue level.
Oxygen diffuses from blood to tissues; carbon dioxide diffuses from tissues to blood.
5. Control of Breathing
Breathing is regulated by the respiratory centers in the brain:
Medulla Oblongata:
Controls the basic rhythm of breathing.
Pons:
Modifies the rate and depth of breathing.
6. Functions of the Respiratory System
Gas Exchange:
Provides oxygen and removes carbon dioxide.
Sound Production:
Vocal cords in the larynx produce sound.
Olfaction (Smell):
Receptors in the nasal cavity detect odors.
Protection:
Mucus and cilia trap and remove particles.
Regulation of Blood pH:
Maintains acid-base balance by controlling carbon dioxide levels.
7. Clinical Relevance
Asthma:
Chronic inflammation of airways causing difficulty in breathing.
Chronic Obstructive Pulmonary Disease (COPD):
Includes chronic bronchitis and emphysema; restricts airflow.
Pneumonia:
Infection causing inflammation of the alveoli.
Tuberculosis:
Bacterial infection affecting the lungs.
Lung Cancer:
Malignant growth in lung tissue.
Pleural Effusion:
Accumulation of fluid in the pleural cavity.
8. Respiratory Volumes
Volume
Description
Average Value
Tidal Volume (TV):
Air inhaled or exhaled in a normal breath
~500 mL
Inspiratory Reserve Volume (IRV):
Extra air inhaled beyond normal inhalation
~3,000 mL
Expiratory Reserve Volume (ERV):
Extra air exhaled beyond normal exhalation
~1,200 mL
Residual Volume (RV):
Air remaining in lungs after maximal exhalation
~1,200 mL
abdominal,
Abdominal Anatomy and Function
The abdomen is a vital region of the body located between the thorax (chest) and pelvis. It contains important organs involved in digestion, excretion, and other metabolic processes. The abdomen is bounded by the abdominal wall, diaphragm, and pelvic inlet.
1. Boundaries of the Abdomen
Superior Boundary:
Diaphragm separates the abdomen from the thorax.
Inferior Boundary:
Pelvic inlet separates the abdomen from the pelvis.
Anterior and Lateral Boundaries:
Abdominal wall (muscles and connective tissue).
Posterior Boundary:
Vertebral column and associated muscles.
2. Abdominal Regions and Quadrants
A. Nine Abdominal Regions
Used in clinical practice to localize organs and symptoms.
Right Hypochondriac: Liver, gallbladder.
Epigastric: Stomach, pancreas.
Left Hypochondriac: Spleen, stomach.
Right Lumbar: Ascending colon, right kidney.
Umbilical: Small intestine, transverse colon.
Left Lumbar: Descending colon, left kidney.
Right Iliac (Inguinal): Appendix, cecum.
Hypogastric (Pubic): Bladder, uterus.
Left Iliac (Inguinal): Sigmoid colon.
B. Four Quadrants
Simpler division for diagnosis.
Right Upper Quadrant (RUQ): Liver, gallbladder.
Left Upper Quadrant (LUQ): Stomach, spleen.
Right Lower Quadrant (RLQ): Appendix, right ovary.
Left Lower Quadrant (LLQ): Sigmoid colon, left ovary.
3. Layers of the Abdominal Wall
Skin:
Outermost protective layer.
Subcutaneous Tissue:
Fatty layer beneath the skin.
Muscles:
Provide support, movement, and protection.
Key muscles:
External Oblique: Most superficial; compresses abdominal contents.
Internal Oblique: Beneath the external oblique; assists in trunk rotation.
Transversus Abdominis: Deepest layer; compresses the abdomen.
Rectus Abdominis: “Six-pack” muscle; involved in trunk flexion.
Fascia:
Connective tissue layers.
Peritoneum:
Parietal Peritoneum: Lines the abdominal wall.
Visceral Peritoneum: Covers abdominal organs.
4. Abdominal Organs
A. Digestive Organs
Stomach:
Located in the LUQ.
Mixes and breaks down food with digestive enzymes and acids.
Liver:
Largest organ in the RUQ.
Produces bile, detoxifies blood, and stores glycogen.
Gallbladder:
Stores bile produced by the liver.
Small Intestine:
Composed of the duodenum, jejunum, and ileum.
Responsible for nutrient absorption.
Large Intestine:
Includes the cecum, colon, rectum, and anal canal.
Absorbs water and forms feces.
Pancreas:
Produces digestive enzymes and insulin.
B. Urinary Organs
Kidneys:
Located retroperitoneally.
Filter blood to form urine.
Ureters:
Transport urine from kidneys to the bladder.
Bladder:
Stores urine before excretion.
C. Reproductive Organs
Female: Uterus, ovaries, fallopian tubes.
Male: Prostate gland, parts of the vas deferens.
D. Spleen:
Located in the LUQ.
Part of the lymphatic system; filters blood and fights infection.
5. Blood Supply to the Abdomen
Arteries:
Supplied by the abdominal aorta.
Major branches:
Celiac Trunk: Supplies liver, stomach, spleen, and pancreas.
Superior Mesenteric Artery: Supplies the small intestine and part of the large intestine.
Inferior Mesenteric Artery: Supplies the distal colon.
Veins:
Drained by the inferior vena cava and portal vein.
Portal vein carries nutrient-rich blood from the digestive tract to the liver.
6. Functions of the Abdomen
Digestion and Absorption:
Processes food and absorbs nutrients.
Protection:
Shields vital organs from trauma.
Support:
Abdominal muscles support posture and movement.
Waste Removal:
Eliminates solid and liquid waste.
Endocrine Function:
Pancreas and adrenal glands produce hormones.
pelvic floor
Pelvic Floor: Anatomy and Function
The pelvic floor is a group of muscles, ligaments, and connective tissues that span the bottom of the pelvis, forming a supportive sling for the pelvic organs. It plays a vital role in supporting internal structures, maintaining continence, and facilitating childbirth.
1. Anatomy of the Pelvic Floor
A. Layers of the Pelvic Floor
The pelvic floor has three layers:
Superficial Layer:
Located close to the skin and responsible for external support and sexual function.
Key muscles:
Bulbospongiosus: Compresses the vagina or penis.
Ischiocavernosus: Maintains erection in males and tenses the vagina in females.
Superficial Transverse Perineal Muscle: Stabilizes the perineal body.
Deep Transverse Perineal Muscle: Provides structural support.
Deep Layer (Pelvic Diaphragm):
Main supportive layer of the pelvic floor.
Key muscles:
Levator Ani Group: Includes:
Pubococcygeus: Supports pelvic organs.
Puborectalis: Maintains continence by creating an anorectal angle.
Iliococcygeus: Provides structural support.
Coccygeus (Ischiococcygeus): Stabilizes the coccyx.
B. Pelvic Floor Ligaments
Ligaments contribute to the stability of the pelvic floor.
Examples:
Sacrotuberous Ligament: Connects the sacrum to the ischial tuberosity.
Sacrospinous Ligament: Connects the sacrum to the ischial spine.
C. Nerve Supply
Pudendal Nerve (S2-S4):
Provides motor and sensory innervation to the pelvic floor.
Pelvic Splanchnic Nerves:
Regulate autonomic functions like bladder and rectal activity.
2. Functions of the Pelvic Floor
Support:
Provides structural support to pelvic organs such as the bladder, uterus, rectum, and intestines.
Continence:
Maintains control over urination and defecation.
Childbirth:
Stretches during labor and aids in the delivery of the baby.
Sexual Function:
Plays a role in sexual arousal and satisfaction.
Stabilization:
Helps maintain posture and supports the spine.
3. Clinical Relevance
Pelvic Floor Dysfunction:
Weakness or injury to the pelvic floor can lead to:
Urinary Incontinence: Leakage of urine during activities like coughing or sneezing.
Fecal Incontinence: Loss of bowel control.
Pelvic Organ Prolapse: Descent of pelvic organs into or outside the vaginal canal.
Chronic Pelvic Pain: Persistent pain due to muscle tension or nerve irritation.
Episiotomy and Tears During Childbirth:
The pelvic floor is often stretched or torn during vaginal delivery, leading to recovery challenges.
Kegel Exercises:
Strengthen pelvic floor muscles, improving continence and support.
Pelvic Floor Disorders in Men:
Issues like prostate surgery may lead to urinary incontinence or erectile dysfunction.
Pelvic Floor Therapy:
Includes physical therapy, biofeedback, and exercises to restore function.
4. Pelvic Floor Exercises (Kegels)
Purpose:
Strengthen the pelvic floor muscles.
Prevent or manage incontinence and support organ positioning.
Steps:
Identify the pelvic floor muscles by stopping urination midstream.
Contract and hold these muscles for 5-10 seconds.
Relax for the same duration.
Perform 10-15 repetitions, 2-3 times daily.
5. Differences in Male and Female Pelvic Floor
Feature
Female Pelvic Floor
Male Pelvic Floor
Function
Supports uterus, vagina, bladder, and rectum
Supports bladder, rectum, and prostate
Vulnerability
Weakened during childbirth
Affected by prostate surgeries
Key Structures
Vagina, uterus, and urethral sphincter
Prostate and external urethral sphincter
pelvic floor muscles,
Pelvic Floor Muscles: Detailed Anatomy and Function
The pelvic floor muscles form a supportive hammock-like structure at the bottom of the pelvis. These muscles play a critical role in supporting pelvic organs, maintaining continence, and aiding in childbirth.
1. Layers of Pelvic Floor Muscles
The pelvic floor muscles are arranged in three layers:
A. Superficial Layer (Superficial Perineal Muscles):
These muscles are close to the skin and support the perineum.
Bulbospongiosus:
In males: Compresses the base of the penis, aids in erection, and assists in ejaculation.
In females: Compresses the vaginal opening and helps in clitoral erection.
Ischiocavernosus:
Maintains erection by compressing veins in the penis or clitoris.
Superficial Transverse Perineal Muscle:
Stabilizes the perineal body (central tendon of the perineum).
External Anal Sphincter:
Controls voluntary contraction of the anus.
B. Middle Layer (Urogenital Diaphragm):
These muscles are involved in controlling the urinary and anal sphincters.
Deep Transverse Perineal Muscle:
Provides structural support to the perineum.
External Urethral Sphincter:
Controls the voluntary release of urine.
C. Deep Layer (Pelvic Diaphragm):
This is the main supportive layer of the pelvic floor.
Levator Ani Muscle Group:
The levator ani is the largest and most important group of pelvic floor muscles. It consists of:
Pubococcygeus: Supports the pelvic organs and assists in maintaining continence.
Puborectalis: Forms a sling around the rectum and maintains the anorectal angle for fecal continence.
Iliococcygeus: Supports the pelvic viscera and provides additional strength.
Coccygeus (Ischiococcygeus):
Supports the coccyx and helps stabilize the pelvic floor.
2. Functions of Pelvic Floor Muscles
Support of Pelvic Organs:
Holds the bladder, uterus (in females), rectum, and intestines in place.
Continence:
Maintains control over the bladder and bowel.
Childbirth:
Stretches during labor to facilitate delivery.
Sexual Function:
Enhances arousal and satisfaction by supporting sexual organs.
Posture and Stability:
Contributes to overall posture and supports the spine and pelvis.
3. Nerve Supply
Pudendal Nerve (S2-S4):
Provides motor and sensory innervation to most of the pelvic floor muscles.
Sacral Nerves:
Contribute to innervation of deeper muscles.
4. Blood Supply
Internal Pudendal Artery:
Supplies blood to the superficial and deep pelvic floor muscles.
5. Pelvic Floor Disorders
Pelvic Organ Prolapse:
Descent of pelvic organs into or outside the vaginal canal due to weakened muscles.
Urinary Incontinence:
Inability to control urine leakage, often due to weak sphincters.
Fecal Incontinence:
Loss of bowel control caused by damage to the anal sphincter or pelvic muscles.
Chronic Pelvic Pain:
Muscle tension or nerve irritation may cause persistent discomfort.
6. Pelvic Floor Exercises (Kegel Exercises)
Steps:
Identify the pelvic floor muscles by stopping urine midstream (this is only for recognition, not routine practice).
Contract the muscles and hold for 5–10 seconds.
Relax the muscles for the same duration.
Repeat 10–15 times, 2–3 times daily.
Benefits:
Improves bladder and bowel control.
Supports recovery after childbirth.
Enhances sexual function.
Prevents or manages pelvic organ prolapse.
7. Gender-Specific Roles
In Females:
Supports the uterus, bladder, and vagina.
Assists during childbirth and postpartum recovery.
In Males:
Supports the prostate and bladder.
Plays a role in maintaining erections and controlling ejaculation.
gluteal muscles and vastus lateralis
Gluteal Muscles: Anatomy and Function
The gluteal muscles are a group of three muscles located in the buttock region. They are responsible for hip movement, posture, and stability.
1. Gluteal Muscles
A. Gluteus Maximus
Location: Largest and most superficial gluteal muscle.
Origin:
Ilium (posterior surface).
Sacrum and coccyx.
Sacrotuberous ligament.
Insertion:
Iliotibial tract (IT band).
Gluteal tuberosity of the femur.
Function:
Extends the hip (e.g., climbing stairs, rising from a sitting position).
Lateral surface of the greater trochanter of the femur.
Function:
Abducts the thigh.
Stabilizes the pelvis during walking.
Nerve Supply: Superior gluteal nerve (L4, L5, S1).
C. Gluteus Minimus
Location: Smallest and deepest of the gluteal muscles.
Origin:
Outer surface of the ilium (below the gluteus medius).
Insertion:
Anterior surface of the greater trochanter of the femur.
Function:
Abducts and medially rotates the thigh.
Stabilizes the pelvis during gait.
Nerve Supply: Superior gluteal nerve (L4, L5, S1).
Functions of Gluteal Muscles
Hip Movement:
Extension, abduction, and rotation of the thigh.
Postural Support:
Maintain upright posture and stabilize the pelvis.
Walking and Running:
Ensure smooth gait and prevent the pelvis from dropping on the unsupported side.
Clinical Relevance
Trendelenburg Gait:
Caused by weakness of the gluteus medius and minimus, resulting in pelvic drop during walking.
Gluteal Injuries:
Strains or tears can affect hip extension and stability.
Intramuscular Injections:
The gluteus medius is a common site for injections to avoid the sciatic nerve.
Vastus Lateralis: Anatomy and Function
The vastus lateralis is one of the four muscles of the quadriceps femoris group located in the anterior thigh. It is the largest and most lateral of the quadriceps muscles.
1. Anatomy of Vastus Lateralis
Origin:
Greater trochanter of the femur.
Lateral lip of the linea aspera.
Insertion:
Tibial tuberosity via the quadriceps tendon and patellar ligament.
Function:
Knee Extension:
Straightens the leg at the knee joint (e.g., walking, running, squatting).
Stabilizes the Patella:
Ensures proper alignment of the kneecap.
Nerve Supply:
Femoral Nerve (L2, L3, L4).
2. Clinical Relevance
Intramuscular Injections:
Common site for injections, especially in infants and children, due to its large size and accessibility.
Quadriceps Weakness:
Can lead to difficulty with knee extension and instability.
Patellofemoral Pain Syndrome:
Improper tracking of the patella, sometimes associated with imbalances in the quadriceps muscles, including the vastus lateralis.
Exercises to Strengthen Gluteal Muscles and Vastus Lateralis
For Gluteal Muscles:
Squats: Target the gluteus maximus and medius.
Lunges: Strengthen all gluteal muscles.
Hip Thrusts: Focus on the gluteus maximus.
Side-Lying Leg Lifts: Activate the gluteus medius and minimus.
For Vastus Lateralis:
Leg Press: Engages the quadriceps.
Lunges: Focus on knee extension.
Step-Ups: Strengthen the vastus lateralis and other quadriceps muscles.
Wall Sits: Isometric exercise targeting the quadriceps.
Major muscles involved in nursing procedures
Major Muscles Involved in Nursing Procedures
Nurses perform a variety of tasks that require the engagement of specific muscle groups. These tasks often involve lifting, transferring patients, positioning, administering injections, and performing other physical activities. Below is a breakdown of the major muscles used in nursing procedures and their relevance.
1. Muscles Used in Lifting and Transferring Patients
A. Upper Body Muscles
Deltoid:
Assists in lifting and abducting the arm during patient transfers.
Biceps Brachii:
Responsible for elbow flexion when lifting or supporting the patient.
Triceps Brachii:
Helps in extending the arm during pushing motions.
Pectoralis Major:
Assists in pushing and pulling activities during transfers.
Trapezius:
Stabilizes the shoulders and upper back during lifting.
Latissimus Dorsi:
Supports pulling motions while transferring patients.
B. Core Muscles
Rectus Abdominis:
Provides trunk stability during patient handling.
Transversus Abdominis:
Supports core strength and prevents back injuries.
Obliques (Internal and External):
Assist in trunk rotation and lateral movements.
C. Lower Body Muscles
Gluteus Maximus:
Engaged during squatting and lifting from a lower position.
Quadriceps (e.g., Vastus Lateralis):
Extend the knee when rising from a squatting position.
Hamstrings:
Assist in bending the knees during patient transfers.
Gastrocnemius and Soleus:
Provide ankle stability during standing and lifting.
2. Muscles Used in Administering Injections
A. Intramuscular Injections
Gluteus Medius:
Primary site for deep intramuscular injections.
Deltoid:
Common site for smaller volume intramuscular injections.
Vastus Lateralis:
Preferred site for intramuscular injections in infants and children.
B. Subcutaneous Injections
Abdominal Wall Muscles:
Subcutaneous fat over the rectus abdominis is often used for injections like insulin.
Thigh Muscles:
The anterior aspect of the thigh may be used for subcutaneous injections.
3. Muscles Used in Positioning and Turning Patients
A. Back Muscles
Erector Spinae:
Maintains spinal stability while turning or repositioning patients.
Rhomboids:
Assist in pulling the shoulder blades together during turning.
B. Arm and Shoulder Muscles
Biceps and Triceps:
Active in pulling and pushing motions.
Rotator Cuff Muscles:
Stabilize the shoulder joint during movements.
C. Leg and Core Muscles
Gluteus Maximus, Hamstrings, and Quadriceps:
Engage during squatting and lifting.
Core Muscles:
Stabilize the torso and prevent back strain.
4. Muscles Used in Manual CPR (Cardiopulmonary Resuscitation)
Pectoralis Major and Minor:
Generate compressive force for chest compressions.
Deltoid and Triceps Brachii:
Extend and stabilize the arms during compressions.
Rectus Abdominis and Core Muscles:
Maintain posture and prevent fatigue during prolonged CPR.
5. Muscles Used in Assisting with Ambulation
A. Upper Body Muscles
Deltoid, Biceps, and Triceps:
Help stabilize the patient and provide support.
B. Core Muscles
Transversus Abdominis and Erector Spinae:
Maintain balance and trunk stability.
C. Lower Body Muscles
Quadriceps and Gluteal Muscles:
Assist the nurse in maintaining a steady stance while supporting the patient.
6. Muscles Used in Handwashing and Hygiene Practices
Flexor and Extensor Muscles of the Forearm:
Enable hand movements during scrubbing and rinsing.
Intrinsic Hand Muscles:
Facilitate finger movements for thorough cleaning.
7. Muscles Used in Bedside Procedures
A. Feeding a Patient:
Deltoid, Biceps, and Triceps:
Assist in lifting and supporting utensils or feeding equipment.
B. Assisting with Hygiene (e.g., Bed Baths):
Forearm and Hand Muscles:
Enable precise movements for cleaning and handling supplies.
Back and Core Muscles:
Provide stability during prolonged tasks.
C. Foley Catheter Insertion or Dressing Changes:
Intrinsic and Extrinsic Hand Muscles:
Provide dexterity and precision.
Key Tips for Nurses to Protect Muscles
Practice Proper Body Mechanics:
Bend at the hips and knees, not the waist.
Keep the load close to the body.
Strengthen Core Muscles:
Regular exercise to support back health and reduce strain.
Use Assistive Devices:
Use transfer belts, hoists, and slide sheets to minimize physical exertion.