Physiology Department
School of Medicine

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CHAPTERS 1 and 2

TERMINOLOGY:

ANATOMY: Science which studies the structure of the human body.

PHYSIOLOGY: Science which studies the function of the human body.

GROSS ANATOMY: Study of body structures with the unaided eye

• Cytology: The study of cells.
• Cell Biology/Histology: Study of tissues.

BODY ORGANIZATION:

TWELVE BODY SYSTEMS:

Muscular System: Body movement and production of body heat.

Lymphatic System: Body immunity, drainage of tissue fluid.

Endocrine System: Chemical regulation of the body through hormones.

Nervous System: Controls and regulates all other systems in the body.

Circulatory System: Transports and removes metabolites from cells

Digestive System: Controls the breakdown and absorption of foods.

PLANES AND BODY CAVITIES:

THREE PLANES OF REFERENCE:

Sagittal: Vertical plane. Divides the body into right and left portions.

DIRECTIONAL TERMS:

Superior: Toward the head.

Inferior: Away from the head; toward the feet.

Anterior: Toward the front.

Posterior: Toward the back.

Medial: Toward the midline of the body.

Lateral: Away from the midline of the body.
Internal: Away from the surface of the body.

External: Toward the surface of the body.

Proximal: Toward the trunk of the body.

Distal: Away from the trunk of the body.

BODY CAVITIES:

Thoracic Cavity: Lungs, heart, and great vessels.

Pelvic Cavity: Terminal large intestine, urinary bladder, reproductive organs.

Cranial Cavity: Brain.

Vertebral Cavity: Spinal cord.

FOUR QUADRANTS:

Right Lower Quadrant: Small intestine, large intestine, bladder.

Left Lower Quadrant: Small intestine, large intestine, bladder.

TISSUES:

Four basic tissues based on size and appearance.

Epithelial: Covers body surfaces, lines body cavities, ducts, and glands.

Connective: Binds, supports and protects body parts.

Muscle: Production of movement through contraction.

Membranous: Outer layer of skin, inner lining of body cavities, tubes, ducts, and covering of visceral organs.

In most cases, it has no vascular system.

Classified by the number of layers and the shape of cells.

• Glandular: Secretory portion of glands.

CLASSIFICATION OF MEMBRANOUS EPITHELIAL TISSUE:

TERMONOLOGY:

Histology: The microscopic study of the structure of tissues.

Simple: Single layer.

Stratified: Multiple layers.

Basement Membrane: Supportive tissue the epithelial cells attach to.

Keratin: Protein that strengthens tissues.

SIMPLE:

Single layer thick, located where diffusion, absorption, filtration, and secretion occurs.

STRATIFIED:

Two or more layers of cells. Because of being layered the cells are poorly suited for absorption, so they have more of a protective function instead.

• Keratinized Stratified Squamous: Keratin is a protien that strenghtens tissue making it water proof and protecting it from bacteria.
• Nonkeratinized Stratified Squamous: Lines the oral cavity, nasal cavity, vagina. Cells on the exposed surface are alive and always moisturized.

CONNECTIVE TISSUE:

Provides structural and metabolic support for other tissues and organs in the body.

• Connective Tissue Proper
• Cartilage
• Blood
• Bone

CONNECTIVE TISSUE PROPER:

Strong, elastic, and flexible matrix.

Loose Connective Tissue: Binds the skin to muscles, highly vascular. Also called FASIA.

Dense Regular Connective Tissue: Strong and highly flexible. Poor blood supply and doesn’t heal well (i.e., tendons and ligaments).

Elastic Connective Tissue: Easily stretched and maintains original form. Found in the walls of large arteries, larynx, and the bronchial tubes of the trachea.

Reticular Connective Tissue: Forms a supportive network. Incorporates phagocytes to ingest foreign material. Found in the liver, spleen, lymph nodes, and bone marrow.

Adipose Tissue: Protects, insulates and stores fat. Found in the hypodermis of the skin, back of eyeball, around kidneys, greater and lesser omentum, and round joints. Adipose tissue can also retain environmental pollutants.

CARTILAGE:

Supportive and protective connective tissue associated with bones at the articular surface of all moveable joints.

Elastic Cartilage: Provides flexibility (i.e., portions of larynx).

BONE:

Most rigid of all the connective tissues. Made up of compact and spongy bone (where red blood cells are produced.

BLOOD (VASCULAR TISSUE):

Made up of form elements and liquid elements.

• Erythrocytes: rbc
• Leukocytes: wbc
• Thrombocytes: platelets

CHAPTER 6

SKELETAL SYSTEM:

Provides internal support, protection of vital organs, framework for body movement;
production of blood cells.


TWO PARTS OF THE SKELETAL SYSTEM:

AXIAL SKELETON: Forms axis of body and protects organs of the head, neck and trunk – made-up of the SKULL: cranial and facial bones, VERTEBRAL COLUMN: cervical (7), thoracic (12), lumbar (5), sacrum (1 or 4-5); coccyx (1 or 3-5), RIB CAGE: 12 pairs of ribs and sternum

APPENDICULAR SKELETON: Bones of the upper and lower extremities and associated girdles – made up of the PECTORAL GIRDLE: scapula, clavicles, UPPER EXTREMITIES: humerus, ulna, radius, carpals, metacarpals, phalanges, PELVIC GIRDLE: pelvis,

LOWER EXTREMITIES: femur, tibia, fibula, tarsals, metatarsals, phalanges; patella
EXTREMITIES: humerus, ulna, radius, carpals, metacarpals, phalanges, PELVIC GIRDLE: pelvis, LOWER EXTREMITIES: femur, tibia, fibula, tarsals, metatarsals, phalanges; patella


FUNCTIONS OF THE SKELETAL SYSTEM:

Support: Rigid framework for body support.
Protection: Skull and vertebral column protect brain and spinal cord, rib cage
protects heart, lungs and great vessels; pelvic girdle protects pelvic viscera
Body Movement: Bones act as levers (1st, 2nd; 3rd class levers), serve as anchoring attachments for tendons and skeletal muscles.
Blood Cell Production: Production of blood cells (HEMOPOISIS) – blood cells are produced in the red bone marrow located in the spongy bone – produces rbc, wbc and platelets (formed elements of blood).
Mineral Storage: 2/3 of bone weight and gives bones its firmness and strength,
primarily stores CALCIUM (muscle contraction, blood clotting and movement of ions and nutrients across cell membrane) and PHOSPHORUS (required for ATP utilization).


SHAPE OF BONES:

Long: Bones of the upper and lower extremities (humerus, radius, ulna, metacarpals, femur, tibia, fibula, metatarsals and phalanges)
Short: Cube-shaped, found in wrist (carpals) and ankle (tarsals)
Flat: Broad-surfaced bones primarily for muscle attachments and protection of organs (cranial bones, ribs and scapula)
Irregular: Varied shapes (vertebrae)


BONE STRUCTURE:

COMPACT BONE: Hard and dense protective exterior portion of bone.

SPONGY BONE: Deep to compact bone, porous, highly vascular.

Shaft/Diaphyis: Cylinder of compact bone.

Medullary Cavity: Central cavity of diaphysis containing yellow bone marrow
where fat is stored.

Epitjysis: Spongy bone surrounded by compact bone, contains red bone marrow responsible for the formation of rbc, wbc and platelets.

Articular Cartilage: Composed of hyaline cartilage – facilitates joint movement.

Nutrient Foramina: Found along diaphysis, an opening into the bone that allows for vessels to pass into the bone.

Epiphyseal Plate: Responsible for bone growth, changes into an EPIPHYSEAL
LINE once bone ossification is completed.

Periosteum: Dense regular connective tissue over diaphysis, responsible for
tendon/muscle attachment.

BONE TISSUE:

Osteogenic Cells: Releases OSTEOBLASTS (bone-forming cells responsible for bone growth) and OSTEOCLASTS (bone-destroying cells responsible for growth, remodeling and healing).

Osteocytes: Mature OSTEOBLASTS – maintain healthy bone through enzyme
secretion and mineral content regulation.

BONE GROWTH:

Starts in center of typical long bone.
Chondrocytes (cartilage cells) hypertrophy.
Minerals are deposited in a process called Calcification.

PRIMARY OSSIFICATION CENTER: Begins at the center of the diaphysis from hyaline cartilage and develops toward bone ends.

SECONDARY OSSIFICATION CENTER: Proximal and distal epiphyses at
epiphyseal – finally forming the epiphyseal lines when the bone is fully formed.

Bone is continually being remodeled over a person’s life.
The strength of the bone is related to factors such as physical activity levels, genetics, diet, hormones and the intake of minerals such as calcium.
As new bone layers are deposited on the outside surface produced by the osteoblasts the osteoclasts dissolve and reabsorb the old bone tissue.

PRIMARY OSSIFICATION CENTER:

Begins at bone center & works out to proximal/distal ends.
Development of compact bone.

SECONDARY OSSIFICATION CENTER:

Occurs at proximal/distal epiphyses.
At end of secondary ossification bone tissue replaces cartilage tissue EXCEPT at articular ends and epiphyseal plates.
Length of the bone grows at the epiphyseal plates.
Secondary ossification forms spongy bone.

END-STAGE BONE GROWTH:

At the end of bone growth the epiphyseal plates form the epiphyseal line, with the only cartilage remaining at the articular surfaces.

SKULL:

8 cranial bones
12 facial bones

SKULL DEVELOPMENT:

During infancy the bones are not fully developed.
Bones separated by fibrous unions called fontanels.
Fontanels make infants head pliable, allowing for an easier birthing process.

Anterior Fontanel
Posterior Fontanel
Anterolateral Fontanel
Posterolateral Fontanel

FORAMINA OF SKULL:

Carotid Canal: Internal carotid artery and sympathetic nerves.
Jugular Foramen: Internal jugular vein and vagus, glossopharyngeal , & accessory nerves.
Foramen Magnum: Passage for spinal cord.
Mandibular Foramen: Inferior alveolar nerve and vessels.

SUTURES:

Sagittal Suture
Coronal Suture
Lambdoid Suture
Squamous Suture

BONES OF THE SKULL:

Frontal Bone: Anterior roof and forehead.
Parietal Bone: Upper sides and roof.
Temporal Bone: Lower sides of skull.
Occipital Bone: Posterior and most of skull base.
Mandible: Jaw, anchors lower teeth (only moveable bone of skull).
Zygomatic Bone: Cheek bones.
Maxilla: (2 parts) Upper jaw and anchors upper teeth.
External Acoustic Meatus: Ear canal.
Mastoid Process: Inferior, attachment for sternocleidomastoid muscle.
Nasal Bone: Bridge of nose.
Sphenoid Bone: (greater and lesser wings & stella turcica) Inferior part of skull
(basilar).
Occipital Condyle: Articulates with the atlas (1st vertebrae).
Palatine Process of Maxilla & Palatine Bone: Forms hard palate (roof of mouth)
Sella Turcica: Houses pituitary gland.
Cribriform Plate of Ethmoid Bone: Opening for olfactory nerves.

SINUSES:

A hollow space within a bone or other tissue.

Frontal
Sphenoidal
Ethmoidal
Maxillary

SINUSITIS:

An inflammation of one or more paranasal sinuses, due to a variety of factors.
Swelling of the nasal mucous membranes.
Openings from sinuses to the nose maybe obstructed resulting in an accumulation of mucus secretions causing pressure, pain, headache, fever, and local tenderness.


AUDITORY OSSICLES:

MALLEUS (hammer)
INCUS (anvil)
STAPES (stirrup)

Transmits sound impulses through the middle-ear cavity.

HYOID BONE:

Supports the tongue and serves as an attachment for several muscles.
Not directly attached to any other bone.
Frequently fractured during strangulation.

The auditory ossicles and hyoid bone are both considered part of the axial skeleton – along with the skull, vertebral column, and rib cage.

VERTEBRAL COLUMN:

Encloses and protects spinal cord.
Supports skull and allows for its movement.
Articulates with the rib cage.
Provides attachment for truck and back muscles.

COMPOSED OF 33 INDIVIDUAL VERTEBRAE:

Cervical (7)
Thoracic (12)
Lumbar (5)
Sacral (1) (3-5 fused)
Coccygeal (1) (4-5 fused)

FOUR CURVATURES OF THE VERTEBRAL COLUMN:

Cervical Curvature: cervical
Thoracic Curvature: thoracic
Lumbar Curvature: lumbar
Pelvic Curvature: sacral & coccyx

Primary Curves: Thoracic and pelvic; retained by the shape of the fetus.
Secondary Curves: Cervical and lumbar; modifications of fetal shape.

VERTEBRAL STRUCTURE:

Body: Anterior; disk shape.
Vertebral Arch: Posterior; formed by pedicles and lamina.
Vertebral Foramen: Passage of spinal cord.
Intervertebral Foramina: Passage of spinal nerves.
Spinous Process: Muscle attachment.
Transverse Process: Muscle attachment.
Superior Articular Process: Interlock superior and inferior vertebrae together.
Inferior Articular Process: Interlock superior and inferior vertebrae together.
Intervertebral Disks: Fibrocartilage between vertebrae; absorbs shock and provides flexibility.

CERVICAL VERTEBRAE:

Atlas: C1
Axis: C2
Dens: On C2; aids in moving head from side to side.


THORACIC VERTEBRAE:

Articulates with the ribs.

LUMBAR VERTEBRAE:

Largest vertebrae.
Attachments for back muscles.

SACRAL VERTEBRAE:

Foundation for the pelvic girdle.

Sacral Foramina (Posterior & Anterior): Allows for passage of spinal nerves.
Sacroiliac Joint: Formed by the auricular surfaces on the lateral sides of the sacrum, with the ilium of the hip.

COCCYX:

“tailbone”

RIB CAGE:

Consists of thoracic vertebrae, 12 paired ribs, costal cartilage; sternum.
Protects thoracic organs, supports pectoral girdle and upper extremities; involved in breathing.

STERNUM:

Manubrium
Body
Xiphoid Process

RIBS:

12 pairs

True Ribs: 1st seven, anchored to the sternum by costal cartilage.
False Ribs: Next five of the 12 pairs.
Floating Ribs: Last 2 of False Ribs, not attached to the sternum at all.
Costal Grove: Posterior surface, protects costal vessels and nerve.
Intercostal Spaces: Spaces between ribs occupied by intercostal muscles.


CHAPTER 7

PECTORAL GIRDLE:

2 scapulas and 2 clavicles.
Provides attachment areas for muscles that move the shoulder and elbow joints.

CLAVICLE:

Sternoclavicular Joint: Attachment to the Manubrium of sternum (Medial Sternal Extremity).
Acomioclavicular Joint (AC Joint): Attachment to the Acromion of scapula (Lateral Acromial Extremity).

SCAPULA:

Spine: Bone ridge on posterior surface, strengthens and prevents bending.
Acromion: Attachment site for muscles and clavicle.
Glenoid Cavity: Attachment site for head of humerus.
Scapular Notch: Passage for suprascapular nerve.

ARM (BRACHIUM):

The arm is refers only to the upper limb (Humerus).

HUMERUS:

Head: Proximal portion; articulates with glenoid cavity.
Body: “shaft”.
Anatomical Neck: Indentation inferior the head.
Surgical Neck: Inferior to the greater and lesser tubercles, site of frequent fxs.
Greater Tubercle: Rounded process on lateral proximal portion of humerus.
Lesser Tubercle: Rounded process anterior to greater tubercle.
Intertubercular Groove: Passage for the biceps brachii muscle.
Deltoid Tuberosity: Deltoid muscle attachment.
Capitulum: Distal and lateral, articulates with the radius.
Trochlea: Distal and medial, articulates with the ulna.
Humeral Condyle: Made-up of the capitulum and trochlea.
Olecranon Fossa: Distal and posterior, articulates with the olecranon of the ulna, forming the elbow.
Nutrient Foramen: Opening in body for arteries.

FOREARM (ANTEBRACHIUM):

Ulna: medial forearm
Radius: lateral forearm

ULNA:

Articulates primarily with the elbow.

Olecranon: Proximal end, articulates with olecranon fossa of humerus.
Body of Ulna: “shaft”.
Head: Distal end of ulna.

RADIUS:

Articulates primarily with the wrist.

Head: Proximal end of radius.
Tuberosity of Radius: Attachment for biceps brachii muscle.

HAND (MANUS):

- 27 bones
Carpus, Metacarpus, and Phalanges

WRIST (CARPUS):

-8 bones

PALM (METACARPUS):

5 bones
Each consists of a proximal Base, a Body, and a distal Head.

FINGERS (PHALANGES):

14 bones
Proximal, middle and distal rows.
Numbered I to V starting with the thumb (lateral to medial) (except the thumb which has only a proximal and distal phalanx).

PHALANX:

Single finger bone.


POLLEX:

Thumb

COLLES FX:

Fracture of the distal end of radius.
Caused by falling on an outstretched hand.

PELVIC GIRDLE:

Supports the weight of the body.
Protects urinary bladder, reproductive organs and fetus.


GREATER (FALSE) PELVIS

LESSER (TRUE) PELVIS

ILLIUM:

Illiac Crest: Prominence of the hip.
Anterior Superior Illiac Spine
Anterior Inferior Illiac Spine
Posterior Superior Illiac Spine
Posterior Inferior Illiac Spine
Greater Sciatic Notch: Passage for sciatic nerve.
Iliac Tuberosity: Attachment of the sacroiliac ligament.


ISCHIUM:

Ischial Tuberosity: Supports the weight of the body in the sitting position.
Acetabulum: Junction for head of femur.
Obturator Foramen

PUBIS:

Symphysis Pubis: Anterior portion; attachment for both sides of the pelvis.


SEX-RELATED DIFFERENCES IN THE PELVIS:

Male and female differences related to child birth.
Baby passes through lesser pelvis.
(page 180 of text)

THIGH (FEMUR):

Longest, heaviest and strongest bone of the body.

Head: Proximal, articulates with the acetabulum.
Neck: Inferior to the head.
Greater Trochanter
Lesser Trochanter
Linea Aspera: Posterior vertical ridge.
Medial and Lateral Condyles: Articulate with the tibia to form the knee joint.


KNEECAP (PATELLA):

Sesamoid bone.

Base: Broad and superior.
Apex: Narrow and inferior.
Articular Surface: Articulates with the medial and lateral condyles of the femur.


LEG (TIBIA AND FIBULA):

SHINBONE (TIBIA):

Medial and Lateral Condyles: Articulates with the condyles of the femur to form the knee joint.
Tibial Tuberosity: Attachment for the patellar ligament.
Medial Malleolus: Prominent knob, distal medial end of tibia.


FIBULA:

Not important for support.
Important for muscle attachment.

Head: Proximal end.
Lateral Malleolus: Prominent knob, distal lateral end of fibula.


FOOT (PES):

26 bones
Tarsus, Metatarsus, Phalanges

TARSUS:

7 bones

Calcaneus: Largest of tarsal bones, forms heel of foot.
Navicular: Anterior to talus.
Talus: Articulates with the Tibia and Fibula to form the ankle joint.

METATARSUS:

Similar in name and number to the Metacarpus.
Numbered I to V (great toe to little toe).
THE NUMBERING IS MEDIAL TO LATERAL NOT LATERAL TO MEDIAL AS IN THE HAND.
Base (proximal), Body and Head (distal).

PHALANGES:

14 phalanges
Proximal, Middle and Distal Rows
Great Toe (like the thumb) only has a proximal and distal phalanx.

TOE (HALLUX)

TRAMUA AND INJURY:

FRACTURES:

Pathologic Fractures
Traumatic Fractures

Simple (Closed)
Compound (Open)
Partial (Fissured)
Complete
Comminuted
Spiral
Greenstick
Impacted
Transverse
Oblique
Colles’
Pott’s
Avulsion
Depressed
Displaced
Nondisplaced


FRACTURE REPAIR:

3 STEPS TO BONE REPAIR


Fractured hemotoma (swelling and inflammation).

Phagocytic and osteoclast activity. Formation of a bony callus.

Remodeling process.


CHAPTER 8

ARTICULATIONS/JOINTS:

Allow for body movement.

THREE TYPES:

Fibrous
Cartilaginous
Synovial


FIBROUS JOINTS:

THREE TYPES:

Sutures
Syndesmoses
Gomphoses

Tightly bound by fibrous connective tissue.
Immovable to slightly movable.

Sutures: Found only in the skull.


CARTILAGINOUS JOINTS:

TWO TYPES:

Symchondroses
Symphyes

Cushions joint, and allows limited movement in response to twisting or compression forces.

Symphysis: covered with hyaline cartilage, along with a pad of fibrocartilage


SYNOVIAL JOINTS:

Freely movable.
Enclosed by joint capsules containing synovial fluid.

SIX TYPES (based on shape of articular surfaces and motion permitted):

Gliding
Hinge
Pivot
Condyloid
Saddle
Ball-and-socket


RANGE OF MOTION (ROM):

Structure of the bones involved in articulation.
Strength of joint capsule and of associated tendons and ligaments.
The size, arrangement, and action of muscles that span the joint.


SYNOVIAL JOINT STRUCTURE:

Joint Capsule: Enclosed synovial joints.
Synovial Fluid: Lubricating fluid with in joint capsule.
Synovial Membrane: Lines inside of joint capsule; secretes synovial fluid.
Articular Cartilage: Layer of hyaline cartilage surrounding bone’s articular surface Ligaments: Connect bone to bone and bind synovial joints.
Bursae: Filled with synovial fluid; cushions muscles and assist the movement to
tendons or muscles over bony surfaces.


Synovial joints are classified on the basis of their structure and motion.


GLIDING:

Allow side-to-side and back-and-forth movements with some slight rotation.
Simplest type of joint movement.
Intercarpal and intertarsal, and sternoclavicular joints.


HINGE:

Monaxial joints.
Permit only one plane of movement.
Most common type of synovial joints.
Knee, elbow, and fingers.


PIVOT:

Limited movement around a central axis.
Proximal articulation of the radius and ulna.
Articulation between the atlas and axis.


CONDYLOID:

Biaxial joints.
Permits angular movement in two directions (up-and-down; side-to-side).
Radiocarpal and metacarpophalangeal joints.


SADDLE:

Modified condyloid joint.
Allows for a wide range of movement.
Carpometacarpal joint of the thumb (opposition) and between the malleus and incus of the middle ear.


BALL-AND-SOCKET:

Multiaxial joint.
Provides the greatest range of motion of all synovial joints.
Hip and shoulder joints.


MOVEMENTS OF SYNOVIAL JOINTS

The ROM at a synovial joint is determined by the structure of the joint and the
arrangement of associated muscles and bones.

ANGULAR MOVEMENTS:

Flexion
Extension
Abduction
Adduction


CIRCULAR MOVEMENTS:

Rotation:
Circumduction


SPECIAL MOVEMENTS:

Inversion
Eversion
Protraction
Retraction
Elevation
Depression


BIOMECHANICS:

Fulcra: Synovial joints.
Effort: Muscles utilized to produce force.
Resistance: Resisting object moved by the lever arms (bones).


THREE TYPES OF LEVERS:

FIRST-CLASS LEVERS:

“Seesaw”
Fulcrum is between the effort and the resistance.
Atlanto-occipital joint of the head.


SECOND-CLASS LEVERS:

“Wheelbarrow”
Resistance is between the fulcrum and effort.
Performing calf-raises of the leg.


THIRD-CLASS LEVERS:

Effort lies between the fulcrum and the resistance.
Most common lever in the body.
Flexion of the elbow of the forearm.


JOINT TRAUMA/DISEASE:

STRAIN:

Excessive stretching of the tendons or muscles.


SPRAIN:

Tearing of ligaments surrounding a joint.
Usually accompanied by SYNOVITIS (inflammation of joint capsule).

DISLOCATION:

Derangement of the articulating bones of a joint.
More serious than a sprain.
Shoulder knee and hip dislocations are common.


SUBLUXATION:

Partial dislocation of a joint.


BURSITIS:

Inflammation of the joint bursa due to overexertion.


TENDONITIS:

Inflammation of the tendon.
Due to overexertion.


KYPHOSIS (HUNCHBACK):

Exaggeration of the thoracic curve.


LORDOSIS (SWAYBACK):

Abnormal anterior convexity of the lumbar spine.


SCOLIOSIS (CROOKEDNESS):

Abnormal lateral curvature of vertebral column.


RHEUMATOID ARTHRITIS:

Due to an autoimmune attack against joint tissues.
Deterioration of the articular cartilage.
Females are more often affected than males.
Usually begins between 30-50y/o.


OSTEOARTHRITIS:

Due to aging and irritation of the joints.
More common than rheumatoid arthritis.
Less damaging than rheumatoid arthritis.
Articular cartilage soften and disintegrate.


GOUTY ARTHRITIS:

Metabolic disorder.
Abnormal amount of uric acid is retained in the blood and sodium urate crystals are deposited in the joints.
Affected joint fuses without tx.
Occurs more in males than females.


TEMPOROMANDIBULAR JOINT:

Combination of a hinge and gliding joint.

Lateral Ligament
Stylomandibular Ligament
Sphenomandibular Ligament


GLENOHUMERAL JOINT:

Ball-and-socket joint.

Coracohumeral Ligament
Glenohumeral Ligaments


ELBOW JOINT:

Hinge joint.

Radial (lateral) Collateral Ligament
Ulnar (medial) Collateral Ligament
Annular Ligament


COXAL (HIP) JOINT:

Ball-and-socket joint.
More stronger and stable than the shoulder because the hip supports the weight of the body.


Illiofemoral Ligaments
Pubofemoral Ligaments
Ischiofemoral Ligament


TIBIOFEMORAL (KNEE) JOINT:

Hinge joint.
Largest, most complex, and most vulnerable joint in the body.

Anterior Cruciate Ligament
Posterior Cruciate Ligament
Medial Meniscus
Lateral Meniscus
Fibular Collateral Ligament
Tibial Collateral Ligament


TALOCRURAL (ANKLE) JOINT:

Hinge joint.

Deltoid Ligament (medial/tibia)
Lateral Collateral Ligaments (lateral/fibula)

CHAPTER 9

MUSCLE FIBERS:

Sarcolemma: Surrounds each muscle fiber which holds the myofibrils and
myofilaments in place.
Sarcoplasm: Incorporates the sarcoplasmic reticulum, myofibrils, and transverse tubules (T tubules). The T tubules have openings through the sarcolemma.


MYOFIBRILS:

Myofibrils extend parallel from one end of the muscle fiber to the other.
Packed inside the myofibrils are smaller protein filaments called myofilaments.

MYOFILAMENTS:

Made up of thick and thin protein filaments.

Actin: Thin protein filaments.
Myosin: Thick protein filaments.

Area between the repeating Z lines form the basic subunit of skeletal muscle
contraction.
These subunits, from Z line to Z line are called sarcomeres.

MUSCLE CONTRACTION:

When muscles contract, it decreases in length due to the shortening of its
individual fibers.
When the muscle fibers shorten, the myofibrils also shorten, and the respective Z lines come closer together.
But…the actin and myosin protein filaments do not shorten. Instead the actin
filaments slide over and between myosin filaments.

For a muscle fiber to contract, or shorten, they must generate a force greater than the opposing forces that act on the muscle’s insertion point.
In an isotonic contraction the muscle visibly shortens, whereas in an isometric
contraction, movement does not occur.

NEUROMUSCLULAR JUNCTION:

A nerve intervening a muscle has both motor and sensory neurons.
Each motor neuron has an axon that extends from the CNS to a group of skeletal muscles.
At the end of the axon are numerous axon terminals.

Motor End Plates: The point on the sarolemma where the axon terminals
connect.
Neuromuscular Junction: The point at which the motor end plate and the
sacolemma meet.

Synaptic Vessicles: Stores the neurotransmitter Acetycholine.
Acetycholine is released from the synaptic vessicles into the neuromuscular cleft
(synaptic cleft) once a nerve impulse reaches the axon terminal.
Acetycholine contacts the receptor sites located on the sarcolemma to initiate
muscle contraction.

MOTOR UNITS:

A motor unit consists of single motor neuron and the muscle fibers
innervated by the motor neuron.
The number of muscle fibers a motor unit innervates depends on the type of
movement.
Precise movements have a low motor unit to muscle fiber ratios (1:10).
Gross movements have a high motor unit to muscle fiber ratios (1:500).

The magnitude of the task determines the number of motor units that are
activated.
Performing a light task requires few motor units, whereas performing a heavy task requires many motor units.

Muscles with many motor units fatigue faster than muscles with few motor units.
All the muscle fibers activated by a nerve impulse contract simultaneously to their maximum or not at all.

MUSCLES OF THE SHOULDER GIRDLE:

Levator Scapulae:

origin: 1st to 4th cervical vertebrae
insertion: medial border of the scapula
action: elevates scapula

MUSCLES ATTACHED TO THE HUMERUS:

Pectoralis Major:

origin: clavical, sternum, and costal cartilages of second to sixth rib
insertion: crest of greater tubercle of humerus
action: flexes, adducts, and rotates shoulder joint medially

Latissimus Dorsi:

origin: spines of sacral, lumbar, and lower thoracic vertebrae; iliac crest and
lower four ribsinsertion: intertubercular groove of humerus
insertion: intertubercular groove of humerus
action: extends, adducts, and rotates shoulder medially; adducts shoulder joint

Teres Major:

origin: inferior angle and lateral border of scapula
insertion: crest of lesser tubercle of humerous
action: extends shoulder joint, or adducts and rotates shoulder joint medially

Deltoid:

origin: clavicle, acromion and spine of scapula
insertion: deltoid tuberosity of humerus
action: abducts, extends, or flexes shoulder joint

MUSCLES ATTACHED TO THE HUMERUS:

Rotator Cuff Muscles:

Supraspinatus
Infraspinatus
Teres Minor
Subscapularis

Supraspinatus:

origin: superior border of scapular fossa
insertion: greater tubercle of humerus
action: abducts and laterally rotates the shoulder

Infraspinatus:

origin: inferior border of scapular fossa
insertion: greater tubercle of humerus
action: rotates shoulder laterally

Teres Minor:

origin: axillary border of scapula
insertion: greater tubercle of humerous
action: rotates shoulder laterally

Subscapularis:

origin: subscapular fossa
insertion: lesser tubercle of humerus
action: rotates shoulder medially

MUSCLES THAT ACT ON THE FOREARM:

Biceps Brachii (short and long heads):

origin: coracoid process (short head) and tuberosity above the glenoid cavity of
scapula (long head)
insertion: radial tuberosity
action: flexes elbow joint; supinates forearm and hand at radioulnar joint

Brachialis:

origin: anterior body of humerus
insertion: coroniod process of ulna
action: flexes elbow joint

Brachioradialis:

origin: lateral supracondylar ridge of humerus
insertion: proximal to styloid process of radius
action: flexes elbow joint

Brachioradialis:

origin: lateral supracondylar ridge of humerus
insertion: proximal to styloid process of radius
action: flexes elbow joint


Triceps brachii (lateral, long; medial heads):

origin: tuberosity below glenoid cavity (long head); lateral and medial surfaces
of humerus (lateral and medial heads
insertion: olecranon of ulna
action: extends elbow joint

Pronator Teres:

origin: medial epicondyle of humerus
insertion: lateral surface of radius
action: pronates forearm and hand

Supinator:

origin: lateral epicondyle of humerus and crest of ulna
insertion: lateral surface of radius
action: supinates forearm and hand

Pronator Quadratus:

origin: distal fourth of ulna
insertion: distal fourth of radius
action: pronates forearm and hand

MUSCLES ACTING OF THE WRIST AND HAND:

Flexor Carpi Radialis:

origin: medial epicondyle of humerus
insertion: base of second and third metacarpal bones
action: flexes and abducts hand and wrist

Palmaris Longus:

origin: medial epicondyle of humerus
insertion: palmar aponeurosis
action: flexes wrist

Flexor Carpi Ulnaris:

origin: medial epicondyle of humerus and olecranon
insertion: carpal and metacarpal bones
action: flexes and adducts wrist

Thenar Muscles:

Abductor Pollicis Brevis
Flexor Pollicis Brevis
Opponens Pollicis

Hypothenar Muscles:

Abductor Digiti Minimi
Flexor Digiti Minimi
Opponens Digiti Minimi

Extensors of the wrist and fingers:

Extensor Carpi Radialis Longus
Extensor Carpi Radialis Brevis
Extensor Digitorum Communis
Extensor Digiti Minimi
Extensor Carpi Ulnaris
Extensor Pollicis Longus
Extensor Pollicis Brevis
Abductor Pollicis Longus

Don’t need to know deep hand muscles:

MUSCLES THAT ACT ON THE THIGH:

Illiacus:

origin: illiac fossa
insertion: lesser trochanter of femur
action: flexes and rotates thigh laterally at the hip; flexes joints of the vertebral
column


Psoas Major:

origin: transverse process of all lumbar vertebrae
insertion: lesser trochanter
action: flexes and rotates thigh laterally at the hip; flexes joints of the vertebral
column


Gluteus Maximus:

origin: iliac crest, sacrum, coccyx, and aponeurosis of the lumbar region
insertion: gluteal tuberosity and iliotibial tract (IT tract)
action: extends and rotates thigh laterally at the hip


Gluteus Medius:

origin: lateral surface of ilium
insertion: greater trochanter
action: abducts and rotates thigh medially at the hip


Gluteus Minimus:

origin: lateral surface of lower half of ilium
insertion: greater trochanter
action: abducts and rotates thigh medially at the hip


Tensor Fasciae Latae:

origin: anterior border of ilium and iliac crest
insertion: IT tract
action: abducts thigh at the hip


Piriformis (not in vdg book):

origin: sacrum
insertion: greater trochanter of femur
action: abducts and rotates thigh laterally


Obturator Internus (not in vdg book):

origin: inner surface of obturator foramen, pubis, and ischium
insertion: greater trochanter of femur
action: abducts and rotates thigh laterally


Quadratus Femoris (not in vdg book):

origin: ischial tuberosity
insertion: small tubercle on posterior femur
action: adducts and rotates thigh laterally


MUSCLES ON THE THIGH:

Gracilis:

origin: inferior edge of symphysis pubis
insertion: proximal medial surface of tibia
action: adducts thigh at the hip; flexes and rotates leg at the knee


Pectineus:

origin: pectineal line of pubis
insertion: distal to lesser trochanter of femur
action: adducts and flexes thigh at the hip


Adductor Longus:

origin: pubis - below pubic crest
insertion: linea aspera of femur
action: adducts, flexes and laterally rotates thigh at hip


Adductor Brevis:

origin: inferior ramus of pubis
insertion: linea aspera of femur
action: adducts, flexes, and laterally rotates thigh at hip

Adductor Magnus:

origin: inferior ramus of ischium and pubis
insertion: linea aspera and medial epicondyle of femur
action: adducts, flexes, and laterally rotates thigh at hip

Sartorius:

origin: anterior superior iliac spine
insertion: medial surface of tibia
action: flexes knee and hip joints; abducts hip joint; rotates thigh laterally at hip


Rectus Femoris (Quadriceps Femoris):

origin: anterior inferior iliac spine and lip of acetabulum (vdg wrong: ASIS)
insertion: patella by common tendon - continues to patellar ligament to tibial
tuberosity action: extends leg at knee joint


Vastus Intermedius (Quadriceps Femoris):

origin: anterior and lateral surfaces of femur
insertion: patella by common tendon - continues to patellar ligament to tibial
tuberosity action: extends leg at knee joint

Vastus Lateralis (Quadriceps Femoris):

origin: greater trochanter and linea aspera of femur
insertion: patella by common tendon - continues to patellar ligament to tibial
tuberosity action: extends leg at knee joint


Vastus Medialis (Quadriceps Femoris):

origin: medial surface of linea aspera of femur
insertion: patella by common tendon - continues to patellar ligament to tibial
tuberosity action: extends leg at knee joint


Biceps Femoris (long and short heads):

origin: long head - ischial tuberosity; short head - linea aspera of femur
insertion: head of fibula and lateral epicondyle of tibia
action: flexes knee joint; extends and laterally rotates thigh at hip

Semitendinosus:

origin: ischial tuberosity
insertion: proximal portion of medial surface of body of tibia
action: flexes knee joint; extends and medially rotates thigh at hip

Semimembranosus:

origin: ischial tuberosity
insertion: medial epicondyle of tibia
action: flexes knee joint; extends and medially rotates thigh at hip

MUSCLES ON THE LEG:

Tibialis Anterior:

origin: lateral epicodyle and body of tibia
insertion: first metatarsal bone and first cuneiform
action: dorsiflexes ankle and inverts foot

Extensor Hallucis Longus:

origin: anterior surface of fibula and interosseous membrane
insertion: distal phalanx of 1st digit
action: extends great toe and dorsiflexes ankle

Extensor Digitorum Longus:

origin: lateral epicondyle of tibia and anterior surface of fibula
insertion: extensor of 2-5 digits
action: extends 2-5 digits and dorsiflexes foot

Peroneus Tertius:

origin: anterior surface of fibula and interosseous membrane
insertion: dorsal surface of 5th metatarsal
action: dorsiflexes and everts foot

Peroneus Longus and Brevis:

origin: lateral epicondyle of tibia and head and body of fibula/lower aspect of
fibula insertion: dorsal surface of 5th metatarsal/first cuneiform and 1st metatarsal bone action: dorsiflexes and everts foot/plantar flexes and everts foot

Gastrocnemius:

origin: lateral and medial epicodyle of femur
insertion: posterior surface of calcaneus
action: plantar flexes foot and flexes knee joint

Soleus:

origin: posterior aspect of fibula and tibia
insertion: calcaneus
action: plantar flexes foot

Plantaris:

origin: lateral supracondylar ridge of femur
insertion: calcaneus
action: plantar flexes foot

Popliteus:

origin: lateral condyle of femur
insertion: upper posterior aspect of tibia
action: flexes and medially rotates leg at the knee

Flexor Hallucis Longus:

origin: posterior aspect of fibula
insertion: distal phalanx of great toe
action: flexes joint of distal phalanx of great toe

Flexor Digitorum Longus:

origin: posterior surface of tibia
insertion: distal phalanges of 2-5 digits
action: flexes joints of distal phalanges of 2-5 digits

Tibialis Posterior:

origin: tibia and fibula and interosseous membrane
insertion: navicular, cuneiform, cuboid, and metatarsal bones 2-4
action: plantar flexes and inverts foot; supports arches

CHAPTER 11

NERVOUS SYSTEM:

Central Nervous System (CNS)

Peripheral Nervous System (PNS)

CNS and PNS:

The CNS is made up of the brain and spinal cord.

The PNS includes the cranial nerves arising from the brain and the spinal nerves
arising from the spinal cord.

AUTONOMIC NERVOUS SYSTEM:

The Autonomic Nervous System (ANS) is a functional subdivision of both the
CNS and PNS.

The controlling centers for the ANS are located in the CNS.

The PNS portion of the ANS is further subdivided into the Sympathetic and
Parasympathetic Divisions.


FUNCTIONS OF THE NERVOUS SYSTEM:

Orientation of the body to internal and external environments.

Coordination and control of body activities with the assistance of the endocrine
system.

Assimilation of experiences requisite to memory, learning, and intelligence.

Programming of instinctual behavior.

NEURONS AND NEUROGLIA:

The nervous system is made up of two cell types: Neurons and Neuroglia.

Neurons are the basic structural and functional units of the nervous system.

Neurons are nerve cells which are highly specialized with respect to excitability
and conductivity.

Neurons respond to physical and chemical stimuli, conduct impulses, and release specific chemical regulators.

NEURONS AND NEUROGLIA:

Neurons perform functions such as memory, thinking, and regulating other organs and glands.

Neurons cannot divide mitotically. A person is born with all the neurons he or
she is capable of producing.

Neuroglia (glial cells) are supportive cells of the neurons. They are more
abundant that neurons and have limited mitotic ability.

NEURONS:

Cell body: Contains the nucleus and most of the cytoplasm. Nuclei are a
clustering of cell bodies in the CNS and Ganglia are a clustering of cell bodies in the PNS.

Dendrites: Function to receive stimuli and conduct impulses to the cell body.

Axons: Function to conduct impulses away from the cell body

MYELINATION:

Neurons can either be myelinated or unmyelinated.

Myelination is the process in which a neurolemmocyte (Schwann cells) or
oligodendocyte surround a portion of the axon or dendrite to provide support and conduct impulses.

Myelin is a white lipid-protien substance from the neuroglia (neurolemmocytes
and oligodendrocytes) that form the myelin layer.

Myelination occurs both in the CNS and PNS.

It is this myelin that gives the color to the brain and spinal cord called white
matter.

Neurolemmocytes form the myelin in the PNS. Also aid in regeneration of cut
axons.

Oligodendrocytes form the myelin in the CNS.

Neurolemmal Sheath: Covers the outer surface of myelin sheath and promotes
regeneration in the case that a neuron is injured.

Neurofibril Nodes (Nodes of Ranvier): Gaps in the myelin and neurolemmal
sheath which propagates a nerve impulse along a neuron.

CLASSIFICATION OF NEURONS AND NERVES:

Afferent Neurons: Sensory. Takes impulses to the CNS

Efferent Neurons: Motor. Takes impulses away from the CNS. Motor neurons
may be somatic (nonvisceral) or autonomic (visceral).

Association Neurons: Interneurons. Found in the spinal cord and brain. Located between sensory and motor neurons.


CLASSIFICATION OF NEURONS AND NERVES:

Pseudounipolar: Has a single process that divides into two. Mostly consists of
sensory neurons.

Bipolar: Has a process at both ends.

Multipolar: Has several dendrites and one axon extending from the cell body.
These are the most common of the three.

CLASSIFICATION OF NEURONS AND NERVES:

Somatic Sensory: Sensory receptors within the skin, bones, joints, eyes, and ears that receive stimuli and send it to the CNS.


Somatic Motor: Impulses from the CNS to the skeletal muscles to perform
movement.

Visceral Sensory: Sends impulses from visceral organs and blood vessels to the
CNS.

Visceral Motor: Impulses from the CNS that innervate cardiac muscle and
smooth muscle.

CENTRAL NERVOUS SYSTEM:

MENINGES:

The CNS is protected by the skull and spinal cord.
The brain is also protected by three membranous connective tissue coverings
called Meninges.

Dura Mater: Outer layer. Composed of dense connective tissue.

Acachnoid: Middle of the three layers. The subarachnoid space (between the
arachnoid and pia mater) contains the cerebrospinal fluid (CSF).

Pia Mater: Innermost layer. Composed of modified loose connective tissue. It
is highly vascular and supports vessels that supply the brain and spinal cord.

VENTRICLES:

The ventricles are composed of the first and second (lateral ventricles) and the
third and fourth ventricles.

Lateral Ventricles: Located in one of the hemispheres of the cerebrum, inferior
to the corpus callosum.

Third Ventricle: Located in the diencephalon, between the thalami.

Fourth Ventricle: Located in the brain stem between the pons and cerebellum.

CSF:

The ventricles and their supporting structures contain cerebrospinal fluid.

CSF is a clear, lymph-like fluid forming a protective cushion around and within
the brain and spinal cord.

CSF drains metabolic wastes from the nervous tissue into the venous system.


TRANSMISSION OF IMPULSES:

Neurons incorporate the properties of irritability and conductivity to transmit
nerve impulses.
Irritability is the ability of dendrites and cell bodies to respond to a stimulus and
convert it into an impulse.
Conductivity is the transmission of an impulse along an axon or dendrite.
Nerve impulses are the actual movement/exchange of sodium and potassium ions along a nerve fiber.


The transmission of a nerve impulse incorporates the properties of:

polarization
resting potential
depolarization
repolarization

POLARIZATION:

Before a nerve fiber can respond to a stimulus it must be polarized.

A polarized nerve fiber has an abundance of sodium ions on the outside of the
axon membrane and potassium ions on the inside of the axon membrane.

RESTING POTENTIAL:

The resting potential occurs when the polarized nerve fiber has an abundance of sodium ions on the outside of the axon membrane.

When the sodium ions are on the outside of the axon membrane, this produces a difference in an electrical charge called the resting potential.


DEPOLARIZATION:

Depolarization initiates a nerve impulse.

For depolarization to occur, a stimulus of sufficient strength must first arise at the receptor portion of the neuron.

Once depolarization occurs a sequence of ion exchanges occurs between sodium and potassium ions to transmit the nerve impulse.


REPOLARIZATION:

Repolarization is a restoration of the resting potential.

After the axon membrane has reached maximum depolarization, the original
concentrations of sodium and potassium are reestablished.

Once the nerve is fully repolarized it is ready to send another nerve impulse.

ALL-OR-NONE RESPONSE:

Impulses travel in one direction only and is an all-or-none response.

Once an impulse is initiated it will travel the length of a nerve fiber without a loss of voltage.


The speed of the impulse is determined by the diameter of the nerve fiber, its type (myelenated or unmyelinated), and the general physiological condition of the neuron.


(myelenated or unmyelinated), and the general physiological condition of the
neuron.

NERVE SYNAPSES:

Synapse: Functional connection between the axon terminal of a presynaptic
neuron and a dendrite of a post-synaptic neuron.

Axon Terminal/Synaptic Knob: The distal portion of the presynaptic neuron at
the end of the axon.

Synaptic Vesicles: Located in the axon terminal and store the neurotransmitter
acetylcholine.

Synaptic Cleft: Gap separating the presynaptic and postsynaptic membranes in
which acetylcholine is released into from the synaptic vessicles.

GENERAL FEATURES OF THE BRAIN:

The CNS is protected by a bony encasement made up of the skull and vertebral column.

Additionally, the CNS is also protected by three meningeal layers (dura mater,
arachnoid, and pia mater).

The CNS is bathed in CSF that circulates within the four ventricles of the brain
and the central canal of the spinal cord, and the subarachnoid space
surrounding the entire CNS.

Gray matter: Consists of nerve cell bodies and dendrites or bundles of
unmyelinated axons and neuroglia. The gray matter exists as the outer
convoluted cortex layer of the cerebrum and cerebellum of the brain. Also,
specialized gray matter clusters called nuclei are found deep in the white matter.
White matter: Consists of dendrites and myelinated axons that form tracts
within the CNS.

Neurotransmission is regulated by neurotransmitter chemicals called
neuropeptides.

Two neuropeptides, enkephalins and endorphins, numb the brain to pain. They
are released due to stress or pain in trauma and act similar to morphine.

Brain is 2% of a person’s body weight.

The brain receives 20% of the total resting cardiac output.

The brain also receives approximately 30% of the oxygen brought into the body.

SPINAL CORD:

Two principle functions:

Impulse conduction: Neural communication to and from the brain through tracts
of white matter. Ascending tracts conduct impulses from the peripheral sensory
receptors of the body to the brain. Descending tracts conduct motor impulses
from the brain to the muscles, glands, and organs.

Reflex integration: Center for spinal reflexes. Reflex actions occur in skeletal,
cardiac, and smooth muscle. Reflexes occur in swallowing, coughing, sneezing,
vomiting.

STRUCTURE OF THE SPINAL CORD:

The spinal cord extends from the foramen magnum to the level of L1.

Two enlargements: Cervical enlargement located between the third cervical and
second thoracic vertebrae. Lumbar enlargement located between the ninth and
twelfth thoracic vertebrae. These regions provide nerves to the upper and lower extremities, respectively.


Conus Medullaris: Terminal portion of the spinal cord at the level of L1

Filum terminale: Structure composed of pia mater that extends from the conus
medullaris to the coccyx.

Cauda equina: Nerve roots originating from the conus medullaris through the
vertebral canal.

The spinal cord develops as 31 segments, each giving rise to a pair of spinal
nerves.

In the spinal cord the gray matter is centrally located and surrounded by white
matter.
Gray matter is composed of nerve cell bodies, neuroglia, and unmyelinated
interneurons.
White matter is made up of tracts of mylinated sensory and motor neurons.

The amount of white matter increases toward the brain as the nerve tracts become thicker and more gray matter is found in the cervical and lumbar enlargementswhere innervations from the upper and lower extremities make their connections.

Projections of gray matter within the spinal cord are called horns (paired anterior, paired posterior, and paired lateral horns).


Gray commissure: Transverse bar of gray matter that connects the paired horns
across the center of the spinal cord.

Central canal: Found within the gray commissure and is continuous with the
ventricles of the brain for the transport of CSF.

PNS:

The PNS conveys impulses to and from the brain and spinal cord.
Nerves of the PNS are classified as cranial (arising from the brain) or spinal
nerves (arising from the spinal cord).

Sensory nerves: Afferent. Sends impulses to the CNS.

Motor nerves: Efferent. Sends impulses away from the CNS.

Mixed nerves: Made up of both sensory and motor neurons and convey impulses both to and from the CNS.



CHAPTER 12

SPINAL NERVES:

31 pairs of spinal nerves
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Each pair is formed by a union of a posterior (dorsal) root and an anterior
(ventral) root.

Spinal nerves are considered mixed nerves.

Posterior (dorsal) root: sensory
Anterior (ventral) root: motor

Additionally, the posterior root contains the spinal (sensory) ganglion, where the
cell bodies of sensory neurons are located.


SPINAL NERVES:

After the posterior and anterior roots join and form the spinal nerve it branches
into several structures.

Meningeal branch: Branch of the spinal nerve that reenters the vertebral canal
to innervate the meninges, vertebrae, and vertebral ligaments.


POSTERIOR & ANTERIOR RAMI:

Posterior Ramus: Branch which innervates the muscles, joints, and skin of the
back, along the vertebral column.

Anterior Ramus: Branch which innervates the muscles and skin on the lateral
and anterior side of the trunk.


RAMI COMMUNICANTES:

Rami Communicantes: Two branches from each spinal nerve that connect to a
sympathetic trunk ganglion (part of the ANS).

The rami communicantes is composed of a gray (unmyelenated fibers) and white
ramus (myelinated fibers).


NERVE PLEXUSES:

Nerve plexuses are formed through networks of the combination of nerves from
the anterior rami.

Cervical Plexus: Formed by the anterior rami of C1-C4, and part of C5
Brachial Plexus: Formed by the anterior rami of C5-T1, with contributions from
C4 and T2.
Lumbar Plexus: Formed by the anterior rami of spinal nerves of L1-L4, and
from T12.
Sacral Plexus: Formed by the anterior rami of L4, L5, and S1-S4.


CERVICAL PLEXUS:

origin: C1-C4; part of C5

Phrenic Nerve (C4): Innervates the diaphragm and causes the diaphragm to
contract.

Branches: Innervates the neck, and portions of the head and shoulders (levator
scapulae, rhomboideus muscles, trapezius, and sternocleidomastoid.


BRACHIAL PLEXUS:

origin: C5-T1; portions of C4 and T2

Musculocutaneous (anterior division): anterior arm -- biceps; brachialis
Median (anterior division): anterior forearm and hand -- radial portion of palm
of hand and thenar muscles.
Ulnar (anterior division): anterior forearm and small hand muscles -- ulnar
portion of palm of hand


BRACHIAL PLEXUS:

Axillary (posterior division): deltoid and teres minor muscles
Radial (posterior division): all posterior arm and forearm muscles -- triceps and
extensors of forearm

Branches: medial and lateral pectoral nerves, thoracodorsal nerve, suprascapular
nerve, and long thoracic nerve

BRACHIAL PLEXUS – BRANCHES:

Medial and lateral pectoral nerves: From the medial and lateral cords of the
anterior division. Innervates the pectoralis major and minor.
Thoracodorsal nerve: From the posterior cord of the posterior division.
Innervates the latissimus dorsi.
Suprascapular nerve and posterior cord branches: Innervates the rotator cuff
muscles.
Long thoracic nerve: Runs perpendicular to the brachial plexus. Innervates the
serratus anterior.


LUMBAR PLEXUS:

origin: L1-L4; portions of T12

Femoral nerve: Innervates anterior thigh muscles -- quadriceps.
Obturator nerve: Innervates medial thigh muscles -- adductors.


SACRAL PLEXUS:

origin: L4-L5; S1-S4

Gluteal nerves: Innervates all gluteal muscles and tensor fasciae latae
Sciatic nerve: Made up of two parts -- tibial nerve (L4-S3) innervating the
posterior thigh and leg muscles, and the common peroneal/fibular nerve (L4-
S2) innervating the anterior and lateral leg muscles.


Thoracic Nerves
origin: T1-T12

T1-T6: intercostal muscles
T7-T12: abdominal muscles

Dorsal Rami
Also called the posterior ramus.

Do not form plexuses.
The dorsal/posterior rami innervate the splenius and erector spinae muscles.