2025 Anatomy Exam 3 Flashcards
Lectures 9-12: Urinary Tract, Osteo/Myohistory, Skeletal, Muscular
The Urinary System
The Urinary System Parts
The urinary system consists of:
Kidneys—produce urine
And the associated nephrons
Produce urine
Urinary tract—transports/stores urine
Ureters
Urinary bladder
Urethra
Urine is stored in the bladder until it is eliminated (micturition/urination)
The Kidneys
The right kidney
Anterior surface covered by the liver, right colic flexure, and duodenum
The left kidney
Anterior surface covered by the spleen, stomach, pancreas, left colic flexure, and jejunum
Positioned slightly higher than right kidney
An adrenal gland is located on the superior surface of each kidney
The kidneys are retroperitoneal
Three Layers of Kidneys
There are three layers of connective tissue that function to protect the kidneys:
Fibrous capsule
Perinephric fat (perirenal fat capsule)
Renal fascia
Connective Tissue Layers of Kidney
Superficial Anatomy of the Kidney
A typical kidney
Size
10 cm long (4 inches)
5.5 cm wide (2.2 inches)
3 cm thick (1.2 inches)
Sectional view
The medial indentation is the hilum
Renal arteries enter at the hilum
Renal veins and ureters exit at the hilum
Sectional Anatomy of the Kidney
Consists of:
Renal cortex
Renal medulla, deep to the cortex, consisting of:
Renal pyramids
Renal papillae
Renal columns
A kidney lobe consists of a renal pyramid, overlying renal cortex, and adjacent renal columns
Renal pelvis (comprises most of the renal sinus) consists of:
Minor calyx
Major calyx
Calyces of Kidney
Blood Supply of Kidneys
The Blood Supply to the Kidneys
Beginning with blood in the renal arteries, blood flows to:
Afferent arterioles
Glomerular capillaries
25% of the cardiac output goes to the kidneys
Circulation in the Renal Cortex
Flow of Blood
After filtration occurs in the nephrons, blood leaves the kidneys via the following vessels:
Glomerular capillaries
Efferent arteriole
Peritubular capillaries
Cortical radiate veins
Arcuate veins
Interlobar veins
Renal vein
There are no segmental veins
*** We are worried about the Nephrons
Innervation of the Kidneys
Receives sympathetic nerve fibers from the celiac and inferior mesenteric ganglia via renal nerves
Neural innervation serves to:
Regulate renal blood flow and pressure
Stimulate renin release
Stimulate water and sodium ion reabsorption
The Nephron
Histology of the Kidney
The Nephron and Collecting System
Each nephron consists of a renal corpuscle and a renal tubule
Renal corpuscle consists of glomerular capillaries (glomerulus) and glomerular capsule
Glomerular filtrate leaves the glomerular capillaries and enters glomerular capsule
Afferent arteriole and efferent arteriole form the vascular pole
Renal tubule
Proximal convoluted tubule (PCT)
Nephron loop
Distal convoluted tubule (DCT)
Filtrate from the DCT empties into the collecting system
Connecting tubules from several nephrons lead to a common collecting duct
The collecting duct passes through the renal pyramids
Filtrate in the collecting duct then enters the:
Papillary duct → minor calyx → major calyx
Filtrate is now called urine
Urine leaves the kidneys via the urinary tract:
Renal Pelvis to the Ureter → urinary bladder → urethra
Two Main Types of Nephrons
Two main types of nephrons
Cortical nephrons
85 percent of the nephrons are cortical
Most of the nephron is located in the cortex
Have a relatively short nephron loop
Juxtamedullary nephrons
15 percent of the nephrons are juxtamedullary
Capsule is located near the border of the cortex and the medulla
Have a long nephron loop
Functions of the Nephrons
The Nephron and Collecting System
Main functions of the nephron
Reabsorbs useful organic material and ions from the filtrate
Reabsorbs more than 99 percent of the water from the filtrate
Enhances the elimination of wastes by actively secreting them into the filtrate
Parts of Renal Corpuscle
The Renal Corpuscle
Consists of:
Glomerular capsule (Bowman’s capsule)
Glomerular capillaries (glomerulus)
Glomerular capsule consists of:
Capsular outer layer (parietal layer)
Made of squamous cells that are continuous with the lining of the PCT
Folds back to form the visceral layer
Visceral layer
Makes up the epithelial lining of the glomerular capillaries
Renal Corpuscle
The Renal Corpuscle
Filtration within the renal corpuscle involves five filtration barriers
Endothelial surface layer
Glomerular capillary endothelium
Basement membrane
Glomerular epithelium
Subpodocyte space
Filtration within the renal corpuscle
Endothelial surface area
Luminal surface of capillary endothelium has a thick meshwork
Limits filtration of large plasma proteins
Glomerular capillary endothelium
The glomerular capillaries are fenestrated
Have openings 0.06–0.1 microns
Too small for blood to pass through (RBC = 7 microns)
Basement membrane
Encircles the capillary endothelium of two or more capillaries
This dense layer restricts the passage of large proteins but permits smaller proteins
Permits the passage of ions and nutrients
Mesangial cells provide support for capillaries and regulate blood flow and filtration
Glomerular epithelium
Consists of special cells called podocytes
Podocytes have long cellular extensions (secondary processes) that wrap around the basal lamina
These extensions have gaps called filtration slits
Subpodocyte space
Comprises most of the filtration space of the glomerulus
Assists the filtration slits of podocytes
Filtrate passing these barriers consists of water, ions, and small organic molecules (glucose, fatty acids, amino acids, and vitamins)
Filtrate passing through contains very few plasma proteins
Many substances are subsequently reabsorbed in the nephron tubule
The Proximal Convoluted Tubule
Begins at tubular pole of the renal corpuscle
Lined with simple cuboidal epithelium containing microvilli
Reabsorbs:
Organic nutrients
Plasma protein
60 percent of the sodium and chloride ions and water
Other ions (for example, calcium, potassium, phosphate, and bicarbonate)
The Nephron Loop (Loop of Henley)
Descending limb
Water leaves this portion and enters the bloodstream (thereby preventing dehydration)
Ascending limb
Pumps ions (sodium ions and chloride ions) out of the tubular fluid
Impermeable to water
Both loops comprised of simple squamous epithelium
The capillaries surrounding the nephron loop are called the vasa recta
The Distal Convoluted Tubule
Active, regulated secretion of ions and acids
Selective reabsorption of sodium and calcium ions
Reabsorption of water
The Juxtaglomerular Complex
Located in the region of the vascular pole
Consists of:
Macula densa cells
Juxtaglomerular cells
Extraglomerular mesangial cells
Produces two hormones
Renin: involved in regulating blood pressure
Erythropoietin: involved in erythrocyte production
The Collecting System
of Kidneys
Consists of:
Connecting tubules
Collecting ducts
Papillary ducts
The DCT of each nephron connects to a connecting tubule
Several connecting tubules drain into a collecting duct
The cells of the collecting ducts make final adjustments to the concentration of the urine that is about to exit the kidneys
Several collecting ducts converge and empty into a papillary duct
Papillary ducts empty into minor calyxes
At this point the filtrate is no longer modified and is properly called urine
Epithelium of collecting system
Begins as simple cuboidal in collecting tubules
Transitions to simple columnar in collecting and papillary ducts
Urine moves from minor calyx to major calyx
Then drains to renal pelvis
Then drains to ureters
Transitional epithelium lines the minor and major calyces and renal pelvis
The Ureters
Exit the kidney at the hilum area
Extend to the urinary bladder
Enter the urinary bladder on the posterior/inferior side
The ureteral orifices enter the urinary bladder in the trigone area
Peristaltic contractions and gravity move urine toward the urinary bladder
Histology of the Ureters
Each ureter consists of three layers
Inner mucosa
Lined with transitional epithelium
Middle muscular layer
Consisting of longitudinal and circular smooth muscles
Adventitia
This is continuous with the fibrous capsule and parietal peritoneum
The Urinary Bladder Male
Males
The base of the urinary bladder is between the rectum and the symphysis pubis
The Urinary Bladder Male (Lateral View)
The Urinary Bladder Female (Lateral View)
Females
The base of the urinary bladder is inferior to the uterus and anterior to the vagina
Histology of the Urinary Bladder
Mucosa
Has folds called rugae to increase bladder volume
Lined by transitional epithelium
Trigone region funnels urine to the urethra
The smooth muscle layer of the urinary bladder is called the detrusor
The neck of the urinary bladder surrounds the entrance to the urethra
Lined with a smooth muscle that makes up the internal urethral sphincter
This is under involuntary control
The Urethra
Female
3 to 5 cm in length
The external urethral orifice is near the anterior wall of the vagina
Transitional epithelium only at neck of the urinary bladder, remainder is stratified squamous
Male
18 to 20 cm in length
Subdivided to form the prostatic urethra, membranous urethra, and spongy urethra
Complex histology
Transitional epithelium near bladder
Changes to pseudostratified columnar then stratified columnar
Finally, stratified squamous near external urethral opening
Prostatic urethra
Passes through the prostate gland
Membranous urethra
Short segment that penetrates the muscular wall of the pelvic cavity in the inguinal region
Spongy urethra (penile urethra)
Extends through the penis to the external urethral orifice
As the urethra passes through there is a skeletal muscle that makes up the external urethral sphincter
This is under voluntary control—this is the sphincter we learned to control as an infant
We lose control as we age
We lose control due to some spinal cord injuries
Skeletal System Introduction
Structure of Bone
The Histological Organization of Mature Bone
Collagen gives tensile strength
The Cells of Mature Bone
Osteocytes
Mature bone cells
Maintain the protein and mineral content of the matrix
Osteoblasts
Immature bone cells
Build the Matrix
Osteoblasts convert to osteocytes
Secrete osteoid, an unmineralized protein matrix that helps form bone tissue.
Osteoprogenitor cells
Found on the inner and outer surfaces of bones
Differentiate to form new osteoblasts
Osteoclasts
Secrete acids, which dissolve the bones
Active when we need Calcium… receive PTHormone and start to dissolve the matrix
Bone Cells
The Osteon
It is the basic unit of skeletal bones
Consists of:
Central canal (Haversian canal) – Vascular and nerve supply of the osteon
Canaliculi – Processes of the osteocyte. Serves for the passage of substances between the osteocytes and blood vessels
Lacunae – Osteocytes contained within
Lamellae – Bone matrix (the rings of the bone)
Histological Structure of a Typical Bone
Single Osteon
Two types of osseous tissue
Compact bone (dense bone)
Compact bones are dense and solid
Forms the walls of bone outlining the medullary cavity
Medullary cavity consists of bone marrow
Spongy bone (trabecular bone)
Open network of plates
Concentric lamellea = matrix
Spongy Bone
Structural Differences of Two Bone Types
Compact bone
Consists of osteons
Makes up the dense, solid portion of bone
Spongy bone
Trabeculae are arranged in parallel struts
Trabeculae form branching plates
Trabeculae form an open network
Creates the lightweight nature of bones
Functional Differences of Two Types of Bone Types
Compact bone
Conducts stress from one area of the body to another area of the body
Generates tremendous strength from end to end
Weak strength when stress is applied to the side
Spongy bone
Trabeculae create strength to deal with stress from the side
Bone Parts (1)
Red Marrow gets replaced as we get older with Yellow Marrow (fat)
Bone Parts (2)
Epiphysis of Bone
Organization of Compact and Spongy Bone
Epiphysis
Each end of the long bones
Diaphysis
Shaft of the long bones
Metaphysis
Narrow growth zone between the epiphysis and the diaphysis
Disappears as we become adults
The Periosteum
Periosteum
Outer surface of the bone
Isolates and protects the bone from surrounding tissue
Provides a route and a place for attachment for circulatory and nervous supply
Senses pain
Attaches the bone to the connective tissue network of the deep fascia
Periosteum and Tendons
Tendons are cemented into the lamellae by osteoblasts
Therefore, tendons are actually a part of the bone
Tendon grows into blood
Enthesis = where bone and tendon meet
Endosteum
Inner surface of bone
Lines the medullary cavity
Consists of osteoprogenitor cells
Anatomy and Histology of the Periosteum and Endosteum
Bone Development and Growth
The Epiphyseal plate aka the “growth plate”
Area of cartilage in the metaphysis
Also called the epiphyseal cartilage
Cartilage near the diaphysis is converted to bone
The width of this zone gets narrower as we age
Circulatory Supply to a Mature Bone
Factors Regulating Bone Growth
Nutrition
Calcium ions
Phosphate ions (inverse relationship with calcium)
Magnesium ions (parallel relationship with calcium)
Citrate
Carbonate ions
Sodium ions
Vitamins A, C, D (calcitriol)
Exercise
18-19 years old bone growth is essentially over
Excess Growth hormone before puberty = gigantism
Excess Growth hormone after puberty = acromegaly (but doesn’t lengthening the bones because plates already closed)
Categories of Bones
There are seven broad categories of bones according to their shapes:
Sutural bones
Irregular bones
Short bones
Pneumatized bones
Flat bones
Long bones
Sesamoid bones
Bone Markings Include
Projections
Tuberosities, trochanters, tubercle, trochlea
Depressions
Grooves, sulci (e.g. sulcus tali), fossa,
Fissures – deeper sulci or canyon like
Foramina (hole)
Canals (meatuses)
Muscle Introduction
Skeletal = Striated = Voluntary
Visceral = Smooth = Involuntary
Cardiac = Have Striations = Involuntary
Muscle Tissue Four Basic Properties
Anatomy of Skeletal Muscles
Gross anatomy is the study of:
Overall organization of muscles
Connective tissue associated with muscles
Nerves associated with muscles
Blood vessels associated with muscles
Microscopic anatomy is the study of:
Myofibrils
Myofilaments
Sarcomeres
Gross Anatomy of Muscle
Connective tissue of muscle:
Epimysium: dense tissue that surrounds the entire muscle
Perimysium: dense tissue that divides the muscle into parallel compartments of fascicles
Endomysium: dense tissue that surrounds individual muscle fibers
Tendons and Aponeuroses:
Epimysium, perimysium, and endomysium converge to form tendons
Tendons connect a muscle to a bone
Aponeuroses connect a muscle to a muscle
Nerves and blood vessels:
Nerves innervate the muscle
There is a chemical communication between a nerve and a muscle
The nerve is “connected” to the muscle via the motor end plate
This is the neuromuscular junction
Blood vessels innervate the endomysium of the muscle
They then branch to form coiled networks to accommodate flexion and extension of the muscle
Neuromuscular Junction (1)
Neuromuscular Junction Actual
Motor End Plate
Axon Terminal and Muscle Fiber do not touch = neuromuscular junction
Has Sodium Channels in it on the muscle side, which leads to depolarization
Microanatomy of skeletal muscle fibers
Sarcolemma
Membrane that surrounds the muscle cell
Sarcoplasm
The cytosol of the muscle cell
Muscle fiber (same thing as a muscle cell)
Can be 30–40 cm in length
Multinucleated (each muscle cell has hundreds of nuclei)
Nuclei are located just deep to the sarcolemma
Storage in Muscle:
Glucose = Glycogen
Hemoglobin = Myoglobin
The Formation and Structure of a Skeletal Muscle Fiber
Myofibrils and Myofilaments
The sarcoplasm contains myofibrils:
Myofibrils are responsible for the contraction of muscles
Myofibrils are attached to the sarcolemma at each end of the muscle cell
Surrounding each myofibril is the sarcoplasmic reticulum
Myofibrils are made of myofilaments:
Actin
Myosin
Sarcomere Structure
Sarcomere Organization
Myosin (thick filament)
Actin (thin filament)
Both are arranged in repeating units called sarcomeres
All the myofilaments are arranged parallel to the long axis of the cell
Sarcomere
Main functioning unit of muscle fibers
Approximately 10,000 per myofibril
Consists of overlapping actin and myosin
This overlapping creates the striations that give the skeletal muscle its identifiable characteristic
Each sarcomere consists of:
Z line (Z disc)
I band
A band (overlapping A bands create striations)
H band
M line
Levels of Organization of Muscle
Skeletal muscles consist of muscle fascicles
Muscle fascicles consist of muscle fibers
Muscle fibers consist of myofibrils
Myofibrils consist of sarcomeres
Sarcomeres consist of myofilaments
Myofilaments are made of actin and myosin
Actin
Twisted filament consisting of G actin molecules
Each G actin molecule has an active site (binding site)
Myosin cross-bridges bind to the active sites on actin
Tropomyosin: A protein that covers the binding sites when the muscle is relaxed
Troponin: Holds tropomyosin in position
Motor Units and Muscle Control
Motor Units (motor neurons controlling muscle fibers)
Precise control
A motor neuron controlling two or three muscle fibers
Example: the control over the eye muscles
Less precise control
A motor neuron controlling perhaps 2000 muscle fibers
Example: the control over the leg muscles
The Number is the number of fibers one nerve goes to
Muscles can be classified based on shape or by the arrangement of the fibers
Parallel muscle fibers
Convergent muscle fibers
Pennate muscle fibers:
Unipennate muscle fibers
Bipennate muscle fibers
Multipennate muscle fibers
Circular muscle fibers
Parallel muscle fibers
Muscle fascicles are parallel to the longitudinal axis
Examples: biceps brachii and rectus abdominis
Convergent muscle fibers
Muscle fibers form a broad area but come together at a common point
Example: pectoralis major
Pennate muscle fibers: Unipennate
Muscle fibers form an oblique angle to the tendon of the muscle
An example is unipennate
All the muscle fibers are on the same side of the tendon
Example: extensor digitorum
Pennate muscle fibers: Bipennate
Muscle fibers form an oblique angle to the tendon of the muscle
An example is bipennate
Muscle fibers are on both sides of the tendon
Example: rectus femoris
Pennate muscle fibers: Multipennate
Muscle fibers form an oblique angle to the tendon of the muscle
An example is multipennate
The tendon branches within the muscle
Example: deltoid muscle
Circular muscle fibers
Muscle fibers form concentric rings
Also known as sphincter muscles
Examples: orbicularis oris and orbicularis oculi
Origin, Insertion, and Action
Origin
Point of muscle attachment that remains stationary
Insertion
Point of muscle attachment that is movable
Action
The function of the muscle upon contraction
Two methods of describing muscle actions
The first makes reference to the bone region the muscle is associated with
The biceps brachii muscle causes “flexion of the forearm”
The second makes reference to a specific joint the muscle is associated with
The biceps brachii muscle causes “flexion at the elbow”
Muscle Terminology (1)
Prime movers example:
Biceps brachii – flexes the lower arm
Antagonists example:
Triceps brachii – extends the lower arm
Synergists example:
Latissimus dorsi and teres major – contract to move the arm medially over the posterior body
Fixators example:
Flexor and extensor muscles contract at the same time to stabilize an outstretched hand
Muscle Terminology (2)
Muscle Terminology (3)
Muscle Terminology (4)
Examples of muscle names related to:
Origin and insertion points
Sternocleidomastoid: points of attachment are sternum, clavicle, and mastoid process
Genioglossus: points of attachment are chin and tongue
Primary functions
Flexor carpi radialis: a muscle that is near the radius and flexes the wrist
Adductor longus: a long muscle that adducts the leg
Muscle Terminology (5)
Skeletal System Overview
Axial Skeleton
Axial skeleton
Consists of:
skull bones/auditory ossicles/hyoid/vertebral column/thoracic cage
Appendicular Skeleton
Appendicular skeleton
Consists of:
limbs/pectoral girdle/pelvic girdle
Picture Overview of Skeletal System (Axial)
Ribs
True: 1-7
False: 8-10
Floating: 11-12
Hyoid only bone that doesn’t articulate with other bones
Functions of Axial Skeleton
Cranial and Facial Subdivisions
Associated bones = Ossicles (3 each side)
… and Hyoid to make 7
The Skull Break Down (Picture)
Sutures of the Skull
Squamous suture
Suture between the temporal bone and the parietal bone
Frontonasal suture
Suture between the nasal bones and the frontal bone
The above sutures and the associated bones compose the calvaria
Sutures of Skull (Picture)
Full Overview of the Skull Picture
Occipital Bones
All in contact with the Brain
KNOW These Two:
Foramen magnum
Occipital condyles
Basioccipital
“bridge” anterior to the foramen magnum (inferior view)
External occipital crest and protuberance
Inferior and superior nuchal lines
Hypoglossal canals
Condylar fossa
Parietal Bones
Superior temporal line
Inferior temporal line
The inferior temporal line is parallel to the superior temporal line
Parietal eminence
The smooth surface from the superior temporal line to the sagittal suture area
Frontal Bone (External View)
External view
Frontal suture
Frontal eminence
Squamous part
Superior temporal line
Supra-orbital margins
Superciliary arches
Supra-orbital foramen
Orbital part
Lacrimal fossa
Frontal Bone (Internal View)
Internal View
Frontal crest
Frontal sinuses
Know
Sella turcica (Sphenoid Slide more in detail)
Carotid canal
Foramen spinosum
Foramen ovale
Foramen magnum
WHAT RUNS THROUGH THESE???
Crista galli
Temporal Bones (External View)
External view
Squamous part
Zygomatic process
Temporal process
Zygomatic arch
Temporal part
External acoustic meatus
Tympanic membrane
Stylomastoid foramen
Styloid process
Mastoid process
Mastoid foramen
Jugular fossa
Jugular foramen
Temporal Bones (Internal)
Internal view
Petrous part
Carotid canal
Foramen lacerum
Auditory tube
Tympanic cavity
Auditory ossicles***
Internal acoustic meatus
Sphenoid
Body
Sella turcica (tuberculum sellae, hypophyseal fossa, dorsum sellae)
Anterior and posterior clinoid processes
Foramen rotundum
Optic canals
Optic groove
Greater and lesser wings of the sphenoid
Foramen ovale and foramen spinosum
Ethmoid
KNOW THESE TWO:
Crista galli
Cribriform plate
… also the little air holes???
Superior and middle nasal conchae (Inferior is its own separate bone)
Perpendicular plate
Ethmoidal labyrinth
Cranial Fossae
Anterior cranial fossa
Middle cranial fossa
Extends from the posterior nasal apertures to the petrous parts of the temporal bones
Posterior cranial fossa
Maxillae
Orbital surface
Alveolar processes
Inferior orbital fissure
Infra-orbital foramen
Maxillary sinuses***KNOW THIS ONE
Palatine processes
Incisive fossa
Frontal process
Infra-orbital groove
Bones of Face (Palatine, Nasal, Inferior Nasal)
The Palatine Bones
Palatine bones
Two bones making up part of the roof of the mouth
Posterior to the palatine process of the maxilla *** KNOW THESE
The Nasal Bones
Nasal bones
The two nasal bones articulate with the frontal bone
Inferior Nasal Conchae
Inferior nasal conchae
One on each side of the nasal septum attached to the lateral wall of the nasal cavity
Bones of Face (Zygomatic, Lacrimal, Vomer)
The Zygomatic Bones
Zygomatic bones
Articulate with the zygomatic process of the temporal bone. Form the zygomatic arch
Zygomaticofacial foramen
The Lacrimal Bones
Lacrimal bones
Found in the medial portion of the orbit of the eye
Lacrimal groove leads to the nasolacrimal canal
The Vomer
Vomer
Forms the inferior portion of the nasal septum** KNOW THESE
The Mandible
Body*
Ramus*
Angle*
Condylar processes*
Head
Coronoid process
Mental foramina
Mandibular notch***
Alveolar part
Mylohyoid line
Submandibular fossa
Mandibular foramen
Mandibular canal
KNOW THE PARTS THAT FORM THE ARTICULATION (TMJ)
Orbital
KNOW the superior orbital fissure
Nasal Complex
Consists of:
Anterior nostrils
Posterior nasal apertures
Nasal septum
Vomer
Perpendicular plate of the ethmoid
Nasal wall
Nasal conchae
The Nasal Complex:
The Paranasal Sinuses
Air-filled chambers that open into the nasal cavity.
Frontal sinuses
Sphenoidal sinuses
Maxillary sinuses
Ethmoid air cells
*** All around the nose (Mastoid Sinus IS NOT one of the paranasal sinuses)
Hyoid Bone
Suspended by the stylohyoid ligaments
Does not articulate with any bones and is therefore extremely mobile
Consists of:
Greater and lesser horns
Serve as points for muscle and ligament attachments
Fontanelles of the Infant Skull
Major features of the infant skull
4 major fontanelle areas
Membranous areas where sutures will eventually form
Allow for distortion of the skull during childbirth
Anterior fontanelle (baby’s “soft spot”)
Posterior fontanelle
Sphenoidal fontanelles
Mastoid fontanelles
Vertebral Column
The adult vertebral column is made up of 26 bones
24 vertebrae
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
1 sacrum (5 fused vertebrae)
1 coccyx (3 to 5 fused vertebrae)
Function of Vertebral Column
Encloses and protects the spinal cord
Supports the skull
Supports the weight of the head, neck, and trunk
Transfers weight to the lower limbs
Helps maintain the upright position of the body
Spinal Curves
There are 4 major curves of the vertebral column
Cervical curve (develops around 3 months as baby can hold up head in prone position)
Thoracic curve
Lumbar curve (as the baby starts to learn to walk)
Sacral curve
These curves, along with muscle attachment to the various vertebral processes, help to maintain balance
Babies Spine
The developing infant lacks balance
They lack the proper curvature
They lack muscle coordination
Vertebra
The Vertebral Body
Vertebra (singular) vertebrae (plural)
Supports weight along the axis of the body
An anterior structure
A vertebral body is separated from another vertebral body by a pad of cartilage called the intervertebral disc
Vertebral Arch
The Vertebral Arch
Forms the vertebral foramen
Made of pedicle and laminae
Spinous process projects posteriorly
Transverse processes project laterally
Spina bifida
Malformation of the structures making up the vertebral arch, where the vertebral arch fails to close completely
Articulation of Vertebra
Articular Processes
Superior articular process
Inferior articular process
Vertebral Articulation
Vertebrae have articular facets and a vertebral canal
Vertebral bodies are separated by intervertebral discs
This results in creating a space called the intervertebral foramina***
Vertebral Numbering
Numbering system of vertebrae
Cervical region
C1, C2, C3, etc.
Thoracic region
T1, T2, T3, etc.
Lumbar region
L1, L2, L3, etc.
Cervical Vertebrae
There are 7 cervical vertebrae
Support the weight of the head
Spinous processes are bifid except for C7 (vertebra prominens)
All have transverse foramina
The transverse processes are fused to the costal processes
Two cervical vertebrae have specific names
C1 is the atlas
C2 is the axis
KNOW
Bifid Tip
Spinous Process
Transverse foramen
Vertebral foramen
C1 and C2
The Atlas (C1)
Articulates with the occipital condyles of the skull
Does not have a body
Consists of anterior and posterior vertebral arches/anterior and posterior tubercles/superior articular facets/inferior articular facets
Has the largest vertebral foramen of all vertebrae
Allows the head to nod in a “yes” manner
The Axis (C2)
Has a dens*** a tooth like subject KNOW… part of C2 and holds C2 and C1 together???
The transverse ligament binds the dens to the atlas
Allows the head to move in a “no” manner
C7
Vertebral Prominens (C7)
C7 has a long prominent spinous process
Ligamentum nuchae
Large elastic ligament
Begins at the vertebral prominens and extends to the external occipital crest of the skull
Whiplash
Sudden motion of the head resulting in vertebral damage
Thoracic Vertebrae
There are 12
All have rib articulation points
T1 to T8 have superior and inferior costal facets
T9 to T12 have only one facet
T1 to T10 have transverse costal facets
They support the ribs
Ribs
True: 1-7
False: 8-10
Floating: 11-12
Most spinous processes point inferiorly
Lumbar Vertebrae
There are 5
Support the weight of the torso
Vertebral bodies are quite large
Spinous process points posteriorly
Sacrum
There is one sacrum but consists of five fused vertebrae
Called the Vertebral Keystone
KNOW THE SACRO-ILIAC JOINT
The Coccyx
Consists of three to five fused vertebrae
Adult male coccyx points anteriorly
Adult female coccyx points inferiorly
Coccyx consists of the coccygeal cornua
Thoracic Cage
The thoracic cage has two structural functions
It protects the heart, lungs, thymus, and other structures within the cavity
It serves as the attachment site for muscles involved in:
Respiration
Positioning the vertebral column
Movements of the pectoral girdle and upper limb
Two types of rib classification
Ribs (one type of classification)
True ribs: 1–7
False ribs: 8–12
Ribs (another type of classification)
Vertebrosternal ribs: 1–7
Connects to sternum via costal cartilages
Vertebrochondral ribs: 8–10
Vertebral ribs (floating ribs): 11–12 (no anterior cartilage)
Rib Attachment
Sternum
Consists of:
Manubrium
Body
Xiphoid process
Jugular notch
KNOW THIS (Caesars dagger)
Skeletal System: Appendicular Skeleton Overview
Pectoral girdle
Shoulder bones
Upper limbs
Pelvic girdle
Hip bones
Lower limbs
Pectoral Girdle (Clavicle)
Clavicle
Sternal end: medial end
Acromial end: lateral end
Conoid tubercle: near the acromial end
Costal tuberosity: near the sternal end
… and Scapula
Pectoral Girdle (Scapula)
Anterior view
Body/coracoid process/subscapular fossa
Posterior view
Scapular spine/supraspinous fossa/ infraspinous fossa/acromion
Medial view
Medial border
… and Clavicle
Upper Limb
Upper limb consists of:
Humerus
Ulna
Radius (always on thumb side)
Carpal bones
Metacarpal bones
Phalanges (14 in each hand… phaylx is singular)
The Humerus
Proximal structures
Head
Greater tubercle*
Lesser tubercle*
Anatomical neck
Surgical neck
Intertubercular sulcus
Shaft
Deltoid tuberosity
Distal structures
Capitulum (condyle)*
Radial fossa
Radial groove
Trochlea (condyle)*
Lateral epicondyle
Medial epicondyle
Coronoid fossa
Olecranon fossa
Posterior View of Humorous
The Ulna and Radius
KNOW Olecranon and Radial Head
The Ulna and Radius (Anterior view)
Lateral Proximal View of Ulna
Carpal Bones
Carpal bones
Eight bones of the wrist
Consists of two rows
Proximal carpal bones and distal carpal bones
The joints between each carpal bone has limited sliding and twisting movements
KNOW Scaphoid Bone
Carpal Tunnel Syndrome happens here
Metacarpals and Phalanges
Meta carpals in palms
There are 5 metacarpals
Number I to V
The metacarpal associated with the pollex is number I
Phalanges in the fingers
14 phalanges in each hand (labeled as proximal, middle, and distal)
Pollex only has two phalanges (labeled as proximal and distal)
Pelvic Girdle
2 hip bones
Each called a coxal bone
Each coxal bone is made of:
Ilium/ischium/pubis
Acetabulum
Acetabular notch/acetabular fossa/lunate surface
Lower Limb
The lower limb is made of:
Femur/patella/tibia/fibula tarsals/metatarsals/ phalanges
Fibula always lateral and just a stablizing bone
Hip Bones
Ilium (iliac crests)**
Pubis
Ischium (sits bones) **
Acetabulum
Sacro-Illiac Joint
Know Iliac Fossa
The Femur
Greater trochanter
Lesser trochanter
Condyles
Epicondyles
Patellar Surface
Patella
Not born with it, forms around two years of age
This is a large sesamoid bone
Protects the knee joint
Anterior surface is rough for strong tendon attachment
Posterior surface has concave facets for the femoral condyles
Structures
Apex
Base
Medial facet
Lateral facet
The Tibia
Always medial
Tibia is medial to the fibula
Proximal structures
Tibial tuberosity
Intercondylar eminence
Medial and lateral tubercles of the intercondylar eminence*
Articular surfaces
Soleal line
Medial and lateral condyles*
Anterior margin (entire anterior length)
Interosseous border (entire medial length)
Distal structures
Medial malleolus***
Inferior articular surface
The Fibula
Interosseous membrane of the leg (membrane between the fibula and tibia—the entire length)
The Fibula
Fibula is lateral to the tibia
Proximal structures
Head
Distal structures
Lateral malleolus
No connection to knee cap
Tarsal Bones
Seven bones of the ankle (tarsus)
Calcaneus*
Talus (contains trochlea)* articulates with the Tibia
Navicular
Cuboid
Medial cuneiform bone
Intermediate cuneiform bone
Lateral cuneiform bone
Metatarsals and Phalanges of Feet
Metatarsals
There are 5 metatarsals
Number I to V
The metatarsal associated with the hallux is number I
Phalanges
14 phalanges in each foot (labeled as proximal, middle, and distal)
Hallux only has two phalanges (labeled as proximal and distal)
Skeletal Muscle Subdivisions
Axial musculature
Muscles that position the head and vertebral column
Muscles that move the rib cage
Appendicular musculature
Muscles that stabilize or move the appendicular skeleton
The muscles are innervated by nerves
The Four Groups of Axial Muscles
The axial muscles can be placed into four groups based on location or function
Muscles of the head and neck
Muscles of the vertebral column
Muscles of the rib cage and lateral walls of the abdominal and pelvic cavities
Muscles of the pelvic floor
Muscles of the Head and Neck
Several groups of muscles of the head and neck are:
Muscles of facial expression
Extra-ocular muscles***
Muscles of mastication
Muscles of the tongue
Muscles of the pharynx
Anterior muscles of the neck
Muscles of Facial Expression
Muscles of Facial Expression
Facial expression muscles are divided into five groups
Mouth/eyes/scalp/nose/neck
All are innervated by CN VII
Orbicularis oris***
Buccinator***
Temporoparietalis***
Occipitofrontalis***
Platysma***
Orbicularis oculi
Epicranial aponeurosis
Temporalis
Massetar
Sternocleidomastoid
WHEN KNOWING MUSCLE, NEED TO KNOW:
Name
Action
Origin - attachment to bones that dont move
Insertion - attachment to bones that move
An aponeurosis is a thin sheath of connective tissue that helps connect your muscles to your bones. Aponeuroses are similar to tendons. They support your muscles and give your body strength and stability. Aponeuroses absorb energy when your muscles move. You have aponeuroses all over your body
Extra-ocular Muscles
Extrinsic eye muscles (muscles that control eye movement)
Medial and lateral rectus muscles
Superior and inferior rectus muscles
Superior and inferior oblique muscles
Inferior rectus/medial rectus/superior rectus/inferior oblique: innervated by CN III
Lateral rectus: innervated by CN VI
Superior oblique: innervated by CN IV
Muscles of Mastication
Masseter*
Temporalis*
Pterygoids
All are innervated by CN V
Muscles of the Pharynx
Pharyngeal constrictors: Superior/Middle/Inferior constrictors
***Laryngeal elevators: Palatopharyngeus/ Salpingopharyngeus/Stylopharyngeus
***Palatal muscles: Tensor veli palatini/levator veli palatini
Constrictors are innervated by CN X
Elevators are innervated by CN IX and CN X
Palatals are innervated by CN V and X
Anterior Muscles of the Neck
Digastric: Anterior belly (CN V)/Posterior belly (CN VII)
Mylohyoid: CN V
Geniohyoid: CN XII
Stylohyoid: CN VII
Sternocleidomastoid: CN XI *** (Insertion is mastoid process, Origin is clavical, sternum)
Omohyoid: Cervical nerve C1—C3
Sternothyroid: Cervical nerve C1—C3
Sternohyoid: Cervical nerve C1—C3
Thyrohyoid: CN XII
Muscles of the Vertebral Column
The muscles of the back form three distinct layers
Superficial layer (extrinsic back muscles): move the neck
Intermediate layer (extrinsic back muscles): move the vertebral column
Deep layer (intrinsic back muscles): interconnect the vertebrae
The Intermediate Layer of the Intrinsic Back Muscles
Erector spinae (group of three muscles)
Spinalis (most medial of the three)
Longissimus
Iliocostalis (most lateral of the three)
KNOW ALL THESE
Oblique and Rectus Muscles
These muscles can be grouped in this manner:
Cervical muscles
Scalene muscles
Thoracic muscles
Intercostals/transversus muscles/serratus
Abdominal muscles
Oblique/Transversus abdominis
KNOW ALL THESE
Cervical muscles
Scalene muscles
Anterior
Middle
Posterior
All scalenes will elevate the ribs (inhalation)
Thoracic muscles
***Intercostal muscles
External intercostal: elevates the ribs
Internal intercostal: depresses the ribs
***Transversus thoracis: depresses the ribs
Serratus posterior muscles
Superior: elevates the ribs
Inferior: depresses the ribs
Abdominal muscles
***External oblique
Compresses the abdomen/depresses ribs/laterally flexes the torso
Internal oblique
Compresses the abdomen/depresses ribs/laterally flexes the torso
Transversus abdominis
Compresses the abdomen
***Rectus abdominis
Depresses ribs/flexes vertebral column
Consists of linea alba and tendinous inscriptions
The Diaphragm
Major breathing muscle
When it contracts, the diaphragm lowers to increase the volume of the thoracic cavity
Inhalation
When it relaxes, the diaphragm rises to lower the volume of the thoracic cavity
Exhalation
Muscles of the Perineal Region and the Pelvic Diaphragm
The Perineal Region
Divided into two triangles
Urogenital triangle (anterior triangle)
Anal triangle (posterior triangle)
Pelvic diaphragm: forms the foundation
Muscles of the anal triangle
Coccygeus
***Levator ani
Iliococcygeus
Pubococcygeus
***External anal sphincter
Appendicular musculature
Appendicular muscles are responsible for:
Stabilizing the pectoral and pelvic girdles
Moving the upper and lower limbs
Absorbing shocks and jolts as you walk, run, or jump
Aiding in strengthening the joint area
Two major groups of appendicular muscles:
The muscles of the pectoral girdle and upper limbs
The muscles of the pelvic girdle and lower limbs
Factors Affecting Appendicular Muscle Function: Action Lines of Shoulder Girdle
Action lines of the shoulder joint:
Direction of pull
Flexion and extension at the shoulder joint
Adduction and abduction at the shoulder joint
Medial and lateral rotation at the shoulder joint
Factors Affecting Appendicular Muscle Function: Spurt and Shunt Muscles
Spurt and shunt muscles
Flexors and extensors
Spurt
Muscle that inserts close to the joint
Shunt
Muscle that inserts far away from the joint
Factors Affecting Appendicular Muscle Function: Action lines at the hip joint
Flexion and extension
Abduction and adduction
Medial rotation and lateral rotation
Muscles of the Pectoral Girdle and Upper Limbs
Muscles associated with the pectoral girdle and upper limbs can be divided into four groups
Muscles that position the pectoral girdle
Muscles that move the arm
Muscles that move the forearm and hand
Muscles that move the hand and fingers
Muscles That Position the Pectoral Girdle
These muscles also coordinate with the muscles that move the arm:
Trapezius: Rotates scapula and extend the neck
Rhomboid: Adducts the scapula
Levator scapulae: Elevates the scapula
Pectoralis minor: Protracts the shoulder
Serratus anterior: Protracts the scapula
Subclavius: Protracts the scapula
Muscles That Position the Pectoral Girdle (Anterior View)
Muscles That Move the Arm
Deltoid: Abducts the arm
Supraspinatus: Abduction at the shoulder
Infraspinatus: Lateral rotation at the shoulder
Subscapularis: Medial rotation at the shoulder
Teres major: Extension and medial rotation at shoulder
Teres minor: Lateral rotation and adduction at shoulder
Coracobrachialis: Adduction and flexion at shoulder
Pectoralis major: Adducts, flexes, and medially rotates the arm
Latissimus dorsi: Extension, adduction, medial rotation at shoulder
Rotator cuff: consists of the following muscles: supraspinatus, infraspinatus, subscapularis, and teres minor
Muscles That Move the Arm (Posterior View)
Muscles That Move the Forearm and Hand
Extensor carpi ulnaris: Extension and adduction at wrist
***Triceps brachii: Extension at the elbow
***Biceps brachii: Flexion at the elbow and supinates the forearm
***Brachialis: Flexion at the elbow
***Brachioradialis: Flexion at the elbow
Anconeus: Extension at the elbow
Pronator teres: Pronates the forearm
Supinator: Supinates the forearm
Muscles That Move the Forearm and Hand (Deep Dissection)
Compartments and Sectional Anatomy of the Arm and Forearm
The deep fascia extends between the bones and the superficial fascia and separates the soft tissues of the limb into separate compartments
Lateral intermuscular septum
Medial intermuscular septum
Both septa create compartments within the upper arm
Anterior compartment
Posterior compartment
KNOW WHAT MAKES UP EACH COMPARTMENT
Muscles of the Pelvic Girdle and Lower Limb
The muscles of the lower limbs are larger and more powerful than those of the upper limbs
These muscles can be divided into three groups
Muscles that move the thigh
Muscles that move the leg
Muscles that move the foot and toes
Muscles That Move the Thigh
Originate on the pelvis; many are large and powerful
Four groups
Gluteal group
Lateral rotator group
Adductor group
Iliopsoas group
Muscles That Move the Thigh: The gluteal muscles
Gluteus maximus
Extension and lateral rotation at the hip
Inserts within the tensor fasciae latae via the iliotibial tract to the tibia
Gluteus medius
Abduction and medial rotation at the hip
Gluteus minimus
Abduction and medial rotation at the hip
Tensor fasciae latae
Extension of the knee and lateral rotation of the leg
Muscles That Move the Thigh: The lateral rotator group
***Obturator muscles
Lateral rotation and abduction of hip
Piriformis
Lateral rotation and abduction of hip
***Gemelli muscles
Lateral rotation and abduction of hip
***Quadratus femoris
Lateral rotation of hip
Muscles That Move the Thigh : The adductor group
***Adductor brevis
Adduction and flexion at the hip
***Adductor longus
Adduction and medial rotation at the hip
***Adductor magnus
Adduction at the hip
Pectineus
Flexion and adduction at the hip
***Gracilis
Flexion and medial rotation at the knee
Adduction and medial rotation at the hip
***Sartorius
Crosses hip and knee joint
Muscles That Move the Thigh: The iliopsoas group
Iliacus
Flexion at the hip
Psoas major
Flexion at the hip
Muscles That Move the Leg: Extensors of the knee
Collectively called the quadriceps femoris. The first three in this list are the vastus muscles:
Vastus intermedius
Extends the leg
Vastus lateralis
Extends the leg
Vastus medialis
Extends the leg
Rectus femoris
Extends the leg
Flexion at the hip
KNOW THIS GROUP
Muscles That Move the Leg: Flexors of the knee
Collectively called the hamstrings:
Biceps femoris
Flexes the leg
Extension at the hip
Semimembranosus
Flexes the leg
Semitendinosus
Flexes the leg
Muscles That Move the Leg: Flexors of the knee
Sartorius
Allows crossing of the lower leg
Flexes, abducts, and laterally rotates the hip
Not a part of the quadriceps
Popliteus
Medially rotates the hip
Not a part of the hamstrings
Muscles That Move the Foot and Toes
Extrinsic Muscles of the Foot
Muscles that originate on the distal end of the femur or on the tibia or fibula but yet move the foot and toes
Intrinsic muscles of the foot
Muscles that originate on some aspect of the foot but yet move the toes
Muscles That Move the Foot and Toes
Extrinsic Muscles of the Foot
***Tibialis anterior: Dorsiflexion and inversion of the foot
***Gastrocnemius: Plantar flexion
Fibularis brevis: Plantar flexion and eversion of the foot
Fibularis longus: Plantar flexion and eversion of the foot
Plantaris: Plantar flexion
***Soleus: Plantar flexion
Tibialis posterior: Plantar flexion and inversion of the foot
The gastrocnemius and soleus insert onto the calcaneal tendon, which inserts onto the calcaneus (calcaneal bone)
The superior extensor retinaculum and inferior extensor retinaculum stabilize the tendons in the tarsal area
Musculoskeletal compartments: Thigh
Medial and lateral intermuscular septa
Thigh is divided into compartments:
Anterior
Posterior
Medial
Musculoskeletal compartments: Lower leg
Lower leg is divided into compartments:
Anterior
Lateral
Superficial posterior
Deep posterior
Musculoskeletal compartments: Lower leg (Full Lower Leg View)
