Skeleton and Articulations
Important Note: Always refer back to your common course objectives for the full list of
bones that will be on the exam.
The Skeletal System
The human skeleton consists of 206 bones grouped into two principal
divisions:
Axial skeleton
Consists of the bones that lie around the longitudinal axis of the
human body
Skull bones, auditory ossicles (ear bones), hyoid bone, ribs,
sternum (breastbone), and bones of the vertebral column
Appendicular skeleton
Consists of the bones of the upper and lower limbs (extremities),
plus the bones forming the two girdles (shoulder and pelvic) that
connect the limbs to the axial skeleton
Bones of the Skull
Skull (cranium)
Consists of 22 bones grouped into two categories :
Cranial bones
Eight cranial bones form the cranial cavity
Frontal bone, two parietal bones, two temporal bones, the occipital bone,
the sphenoid bone, ethmoid bone
Facial bones
Fourteen facial bones form the face
Two nasal bones, two maxillae, two zygomatic bones, the mandible, two
lacrimal bones, two palatine bones, two inferior nasal conchae, vomer
Cavities of the Skull
Skull bones form several cavities:
Cranial cavity
Nasal cavity
Orbits (eye sockets)
Paranasal sinuses
Small cavities which house organs involved in hearing and equilibrium
Cranial Bones
Frontal Bone – Forms the forehead
Parietal Bones – Form the sides and roof of the cranial
cavity
Temporal Bones – Form the lateral aspects and floor of
the cranium
Occipital Bone – Forms the posterior part and most of
the base of the cranium
Sphenoid Bone –
Butterfly-shaped bone
Lies at the middle part of the base (floor) of the
skull
Ethmoid Bone
Located on the midline of the cranial floor medial
to the orbits
A major structure of the nasal cavity
Frontal Bone
Identify:
Sinus
Orbits
Supraorbital margin
Parietal Bone
Temporal Bone
Temporal bone:
Identify:
Zygomatic process
Mastoid process
Styloid process
Petrous portion
Mandibular fossa
Carotid canal
Jugular foramen
External auditory meatus
Internal acoustic meatus
Temporal Bone
Occipital Bone
Occipital Bone:
Identify:
Foramen magnum
Occipital condyles
Sphenoid and Ethmoid Bones
Sphenoid Bone –
Butterfly-shaped bone
Lies at the middle part of the base
(floor) of the skull
Identify:
Sella turcica
Greater wing
Lesser wing
Sinus
Optic foramen
Orbital fissures
Ethmoid Bone
Ethmoid Bone
Located on the midline in the anterior part of
the cranial floor medial to the orbits
A major superior supporting structure of the
nasal cavity
Contain thin projections called conchae
which are lined by mucous membranes
Increased surface area in the nasal cavity
helps to humidify inhaled air trapping inhaled
particles
Identify:
Crista galli
Cribriform plate
Olfactory foramina
Perpendicular plate
Superior and middle nasal conchae
Sinus
Cranial Sutures
Sutures:
Identify:
Sagittal
Coronal
Squamous
Lambdoidal
Facial Bones
Identify:
Nasal Bones - Form the bridge of the nose
Maxillae - Form the upper jawbone and most of the hard palate, separates the nasal cavity from
the oral cavity
Zygomatic Bones (cheekbones) - Form the prominences of the cheeks
Lacrimal Bones - Form a part of the medial wall of each orbit
Palatine Bones - Form the posterior portion of the hard palate
Inferior Nasal Conchae - Form a part of the inferior lateral wall of the nasal cavity
Vomer - Forms the inferior portion of the nasal septum
Mandible – Forms lower jaw
Nasal Septum
Divides the interior of the nasal cavity into right and left sides
“Broken nose,” in most cases, refers to septal damage rather than the nasal bones
themselves
Orbits - Eye socket
Vertebral Column
The vertebral column is curved to varying degrees in different locations
Curves increase the column strength
Help maintain balance in the upright position
Absorb shocks during walking, and help protect the vertebrae from fracture
Vertebral Column
Composed of a series of bones called vertebrae (Adult = 26)
7 cervical are in the neck region
12 thoracic are posterior to the thoracic cavity
5 lumbar support the lower back
1 sacrum consists of five fused sacral vertebrae
1 coccyx consists of four fused coccygeal vertebrae
Vertebral Column Regions
Cervical Region
Cervical vertebrae (C1–C7)
The atlas (C1) is the first cervical vertebra
The axis (C2) is the second cervical vertebra
Thoracic Region
Thoracic vertebrae (T1–T12)
Articulate with the ribs
Lumbar Region
Lumbar vertebrae (L1–L5)
Provide for the attachment of the large back muscles
Sacrum
The sacrum is a triangular bone formed by the union of
five sacral vertebrae (S1–S5)
Serves as a strong foundation for the pelvic girdle
Coccyx
The coccyx, like the sacrum, is triangular in shape
It is formed by the fusion of usually four coccygeal
vertebrae
Basic Vertebral Anatomy
Identify:
Body
Vertebral arch
Vertebral foramen
Transverse process
Spinous process
Superior articular process
Inferior articular process
Vertebral Column Features
Identify:
intervertebral foramina
intervertebral discs
Cervical vertebrae
Cervical vertebrae (C1–C7)
The atlas (C1) is the first cervical vertebra
The axis (C2) is the second cervical vertebra
Identify:
Transverse foramen
Atlas
Axis: dens
Thoracic vertebrae
Thoracic vertebrae (T1–T12)
Articulate with the ribs
Identify:
rib facets
Lumbar vertebrae
Lumbar vertebrae (L1–L5)
Provide for the attachment of the large back muscles
Sacrum and Coccyx
Sacrum (S1–S5)
A triangular bone formed by the union of five sacral vertebrae
Foundation for the pelvic girdle
Coccyx
The coccyx, like the sacrum, is triangular in shape
It is formed by the fusion of usually four coccygeal vertebrae
Bones of the Thorax
Thoracic cage is formed by the:
Sternum
Ribs
Costal cartilages
Thoracic vertebrae
Bones of the Thorax
Sternum
“Breastbone” located in the center of the
thoracic wall
Ribs
Twelve pairs of ribs give structural support
to the sides of the thoracic cavity
Costal cartilages
Costal cartilages contribute to the
elasticity of the thoracic cage
Sternum
Identify:
Manubrium
Body
Xiphoid process
Jugular notch
Clavicular notches
Sternal angle
Ribs
Twelve pairs of ribs give structural support to the sides
of the thoracic cavity
Identify:
Costal cartilages
Head
Neck
Body or shaft
Tubercle
Costal groove
Appendicular Skeleton
Pectoral girdle
Pelvic girdle
Upper Appendage (30 bones per upper limb)
1 humerus (arm)
1 ulna (forearm)
1 radius (forearm)
8 carpals (wrist)
5 metacarpal (hand)
14 phalanges (fingers)
Lower Appendage (29 bones per lower limb)
1 femur (thigh)
1 tibia (leg)
1 fibula (leg)
7 tarsal (ankle)
5 metatarsal
14 phalanges (foot)
Pectoral girdle
Clavicle
Identify:
Sternal extremity
Acromial extremity
Scapula (Anterior View)
Identify:
Scapula
Spine
Acromion
Coracoid process
Glenoid cavity
Medial border
Lateral border
Supraspinous fossa
Infraspinous fossa
Subscapular fossa
Scapula (Posterior View)
Humerus
Identify:
Head
Anatomical neck
Surgical neck
Greater tubercle
Lesser tubercle
Body
Deltoid tuberosity
Capitulum
Radial fossa
Trochlea
Coronoid process
Olecranon fossa
Medial epicondyle
Lateral epicondyle
Arm (Radius and Ulna)
Identify:
Radius
Head
Radial tuberosity
Styloid process
Ulnar notch
Ulna
Olecranon process
Coronoid process
Trochlear notch
Radial notch
Head
Styloid process
Carpals, Metacarpals, and Phalanges
Identify:
Carpals
Metacarpals
Phalanges
Pelvic Girdle
Identify:
os coxa/coxal bone:
Ilium
Iliac crest
Anterior superior iliac spine
Anterior inferior iliac spine
Posterior superior iliac spine
Posterior inferior iliac spine
Greater sciatic notch
Iliac fossa
Auricular surface
Ischium
Ischial spine
Lesser sciatic notch
Ischial tuberosity
Ramus of ischium
Obturator foramen
Pubis
Superior ramus of pubis
Inferior ramus of pubis
Pubic symphysis
Acetabulum
Comparing Male and Female Pelves
Males - bone are larger and heavier
Pelvic inlet is smaller and heart shaped
Pubic arch is less the 90°
Female - wider and shallower
Pubic arch is greater than 90°
More space in the true pelvis
Comparing Male and Female Pelves
Femur
Identify:
Head
Neck
Greater trochanter
Lesser trochanter
Medial condyle
Lateral condyle
Medial epicondyle
Lateral epicondyle
Linea aspera
Patella
Identify:
Base
Apex
Articular facets
Leg (Tibia and Fibula)
Identify:
Tibia:
Medial condyle
Lateral condyle
Tibial tuberosity
Medial malleolus
Fibula:
Head
Lateral malleolus
Tibia
Tarsals, Metatarsals, Phalanges
Identify:
Tarsals
Talus
Calcaneus
Metatarsals
Phalanges
Gross Anatomy - Bone Markings Review