Ch.7 The Skeletal System Flashcards
Axial Skeleton
- 80 bones
- skull
- vertebral column
- Thoracic cage = ribs and sternum
The skull
Axial Skeleton
- 22 bones
- facial bones form the anterior
- cranial bones form the posterior
Functions of the skull
- Anchors the teeth
- Houses the special sense organs
- Protects the brain
- Forms the face
- Attachment of muscles
- Forms openings to the respiratory and digestive systems
Cranium bones
8 bones:
- 2 temporal
- 2 parietal
- 1 frontal
- 1 occipital
- 1 sphenoid
- 1 ethmoid
Cranium Features
- Vault: calvera or skull cap covers the brain
- fossa: shadow depressions
- Base: cranial floor
– Brain sits on it
– Forms the posterior, middle, anterior fossas
Sinus’s
- Frontal sinus
- Etmoidal sinus
- Sphenoidal sinus
- Maxillary sinus
- spaces inside of bones
- lined with a mucous membrane
- lighten the skull
- warm and moisten air
- act as resonance chambers in speech
Frontal bone
- Frontal Squama - forehead
- Houses the frontal sinuses
Forms:
1. the brow ridge, supraorbital foramen (vessels & nerves)
2. the superior aspect of the orbit
3. the anterior cranial fossa (supports frontal brain lobe)
Parietal Bone
- Forms superior and lateral aspects of cranium
Sutures:
1. Coronal – separates parietal/frontal
2. Sagittal – separates R. & L. parietals
3. Lambdoidal – separates parietal/occipital
4. Squamous – separates parietal/temporals
Occipital Bone
- Forms the posterior, inferior aspects of cranium
- Posterior cranial fossas (cerebellum sits in them)
- Foramen magnum (for spinal cord)
- Occipital condyles (articulates with first vertebra)
- Hypoglossal canals (allows cranial nerve XII to pass)
Squamous
Temporal Bone Region
contains zygomatic process & mandibular fossa
Tympanic
Temporal Bone Region
contains external acoustic meatus & styloid process (hyoid bone)
Mastoid
Temporal Bone Region
contains mastoid sinus, mastoid process
Petrous
Temporal Bone Region
houses the middle and internal ear structures, contains the carotid canal, forms part of the jugular foramen & middle cranial fossa
Sphenoid Bone
Has a Body & Three sets of processes:
1. greater wings
2. lesser wings
3. pterygoids
- Body contains a sinus & forms sella turcica (pituitary gland sits in it)
- Forms the superior orbital fissure (opening for cranial nerves)
- Forms the optic foramen (optic nerve passes through it)
Ethmoid Bone
- Lateral masses (contains sinuses)
- Perpendicular plate (forms the superior part of the nasal septum)
- Olfactory foramina (for olfactory nerves)
- Crista gali for attachment of the brain meninges
- Superior and middle nasal conchae (protrude into nasal cavity)
Holes in the Skull
- optic foramen
- superior orbital fiisure
- foramen rotundum
- foramen ovale
- foramen spinosum
- foramen magnum
- foramen lacerum
- jugular foramen
Facial Bones
14 bones:
- 1 mandible
- 1 vomer
- 2 maxillae
- 2 zygomatic
- 2 nasal
- 2 lacriminal
- 2 palatines
- 2 inferior nasal conchae
Mandible
- Contains lower teeth sockets
- Has a body and rami
Rami have: - Anterior coronoid process (for attachment of chewing muscles)
- Posterior mandibular condyles (which articulate with mandibular fossas of the temporal bone)
Maxillae Bones
- Forms the upper teeth sockets
- Has the palatine process (which forms the anterior portion of the hard palate)
- Contains sinuses
Zygomatic Bones
Contains the temporal process (which articulates with the zygomatic process of the temporal bone to form the zygomatic arch = cheek bone)
Nasal Bones
form the bridge of the nose
Lacrimal Bones
with the lacriminal fossa
Palatine Bones
forms the posterior portion of the hard palate
Vomer
forms the inferior portion of the nasal septum
Inferior nasal conchae
forms part of the nasal cavity walls
Hyoid Bone
- Located inferior to mandible
- Does not directly articulate with any other bones
- Attaches to the styloid process of the temporal bone
- Supports the tongue, is an attachment for neck muscles and the muscles that move the voice box
The Vertebral Column Functions
- Protect the Spinal Cord
- Supports the head
- Attachment for ribs
- Attachment for skeletal muscles
The Vertebral Column Structure
- 26 irregular vertebrae
- Extends skull to pelvis
- Posterior & anterior ligaments
- Five regions:
1.Cervical (7)
2.Thoracic (12)
3.Lumbar (5)
4.Sacral (1)
5.Coccyx (1)
KNOW
Spine curvature
- Makes spine more like a spring than a rod
4 curves:
1.and 2. Cervical and lumbar convex
3.and 4. Thoracic and sacral concave
Scoliosis
Vetebral Column Disorder
- Spinal cord has lateral(abnormal sideways) curvature
Kyphosis
Vetebral Column Disorder
- exagerated Thoraic curvature
- causes the upper back to curve abnormally forward
- affects geriatric people
Lordosis
Vetebral Column Disorder
- exagerated Lumbar curvature
- affects pregnant women
Vertebral Discs
- in spine
- Separate vertebrae
- Outer fibrocartilage ring
- Inner soft pulp
- Shock absorbers
Herniated disc
- in spine
- a spinal injury that occurs when a spinal disc is forced through a weakened part of the spine
- causes: compression fracture
7 Processes project from vertebral arch
Attachment for muscles:
- 1 Spinous process
- 2 Transverse processes
Articulations for adjoining vertebrae:
- 2 Superior articulating processes
- 2 Inferior articulating processes
C1 = The Atlas
Cervical Vertebra(Spine)
- No body
- Large lateral masses (articulate with the occipital condyles)
- Allows nodding motion
C2 = The Axis
Cervical Vertebra(Spine)
- Dens articulates in arch of Atlas
- Allows head rotation
Structure of C3-C7: - Body is oval
- Spinous process is short, bifid
- Vertebral foramen is large
- Transverse processes have foramen
Thoracic Vertebra(Spine)
- Body is heart shaped
- Spinous process is long, sharp, points inferior
- Body has demifacets (for articulation with head of rib)
- Transverse processes of T1 – T10 have facets (for articulation with tubercle of rib)
Lumbar Vertebra
- Body is large/thick
- Vertebral foreman is small
- Spinous process short, flat, project posterior
- Articular processes are angled for sturdy support
Sacrum
- Fusion of 5 vertebrae
- Forms posterior wall of pelvic girdle
- Promontory = superior surface of S1
- Wings = fusion of transverse processes
- Crest = posterior, medial, fusion of spinous processes, forms the sacral canal
- Hiatus = inferior opening of canal
Coccyx
- Tailbone
- Fusion of 4 reduced size vertebrae
The Bony Thorax
Includes: ribs, sternum, costal cartilage Function:
- Protects thoracic organs
- Support shoulders & upper limbs
- Muscle attachment
The Sternum
- in the bony thorax
Fusion of 3 bones: - Manubrium articulates with clavicles at clavicular notches and ribs 1 & 2
- Body articulates with cartilage of ribs 2-7
- Xiphoid attachment for diaphragm and abdominal muscles
The Ribs
- in the bony thorax
- Shaft with groove for vessels/nerves on inferior border
- Head: posterior end has 2 facets to articulate with vertebral bodies
- Tubercle articulates with transverse processes of vertebra
The Appendicular Skeleton
- Bones of the limbs and their girdles
- Function: locomotion
KNOW
Pectoral Girdle
- Made of paired scapula and clavicles
- Not true girdle – incomplete posteriorly
- allows good range of motion (ROM)
Clavicles
part of Pectoral Girdle
- also known as the collar bone
- S shaped
- Sternal end articulates with manubrium of sternum (rounded and cupped)
- Acromial end articulates with the acromium of scapula (wide, flattened)
- Attachment for shoulder and neck muscles
- Holds limbs laterally (break it they collapse forward)
- Superior surface smooth
- Inferior surface grooved and ridged – trapezoid line & conoid tubercle
Scapula
part of Pectoral Girdle
- Flat, triangular shaped bone
- Lies dorsal from ribs 2 - 7
- Borders: superior, medial, lateral
- Glenoid Fossa articulates with humerus
- Acromion (from spine) articulates with the clavicles
- Corocoid attachment for biceps (bent little finger)
Upper Limb
30 bones form the arm, forearm, and hand
Humerus
- Proximal head articulates with glenoid fossa of scapula
- Tubercles for muscle attachment
- Intertubercle sulcus for bicep tendon
- Deltoid tuberosity for insertion of deltoid muscle of the shoulder
- Distal condyles (capitulum & trochlea) articulate with forearm (radius & ulna)
- Epicondyles for muscle attachment
- Coronoid and olecranon fossas form elbow with the ulnar processes
- Ulnar nerve behind medial epicondyle
Ulna (elbow - pinky side)
- Proximal head (monkey wrench) – olecranon
– Fits into olecranon fossa of humerus to form elbow - Trochlear notch rides on trochlea of humerus
- Coronoid process fits into coronoid
fossa of humerus - Lateral radial notch articulates with the radius
- Distally articulates with the carpels of the hand at styloid process – not responsible for hand movement
Radius – thumb side
- Proximal head like suction cup
- Head articulates with the capitulum
of humerus - Allows rotation
- Radial tuberosity for biceps muscle attachment
- Distal end articulates with carpels
- Styloid process sticks out laterally
Hand
- Carpals: wrist
- Metacarpals: palm
– I thumb
– V pinky finger - Phalanges: fingers
1. distal
2. middle
3. proximal
Carpals
Hand
- 8 marble sized short bones, held tightly together with ligaments
- Only scaphoid & lunate articulate with radius
- Anterior is concave and spanned by broad ligament that several tendons and nerves use as a tunnel
- Inflammation of this ligament = carpal tunnel syndrome
Metacarpals
Hand
- 5 long bones that form the palm
- numbered I - V, lateral to medial
- heads form knuckles when you make a fist
Phalanges
Hand
made of distal, middle and proximal long bones (except pollex, which has only distal and proximal – thumb)
Pelvic Girdle
- Attaches lower limbs to axial skeleton
- Supports the internal viscera
- Made of a pair of coxal bones (hip bones) that are fused anteriorly
– Posteriorly they are fused to the sacrum - Each coxal bone is made from a fusion of 3 bones: ilium, ischium and pubis
Ilium
part of pelvic girdle
- Large irregular bones that articulate with the sacrum
- Consists of body and winglike ala
- Spines for muscle attachment
- Greater sciatic notch is used by the sciatic nerve (largest nerve in body)
Ischium
part of pelvic girdle
- Posterior and inferior coxal bones – L shaped
- Lesser sciatic notch for nerves and blood vessels
- Ischial spine – point of attachment of ligament to sacrum
- Forms the obturator foramen – blood vessels & nerves
- You sit on it
Pubis
part of pelvic girdle
- Anterior coxal bones
- Fused anteriorly w/fibrocartilage disk (pubic symphysis)
- Your bladder sits on it
acetabulum
- on the pelvic girdle
- Where the three bones meet laterally they form a deep Fossa
- acetabulum articulation for head of the femur
Female Pelvic Girdle
- False pelvis shallow
- Large pelvic brim
- Pubic arch (greater than) > 90°
- Sacrum curvature accentuated
Male Pelvic Girdle
- False pelvis deeper
- Small pelvic brim
- Pubic arch (less than) < 90°
- Sacrum curvature straighter
Lower limb
- 30 bones form the thigh, knee, leg, and foot
- Thick, strong, weight bearing bones
Femur
- Longest, strongest bone in the body
- Head forms a ball (fits into the acetabulum)
- Fovea capitis – indentation for ligaments
- Trocanters, tuberosities, and linea aspera for muscle attachment
- Distal condyles articulate with the tibia and patella
Patella
- Sesamoid bone
- Embedded in tendons
Tibia
- Medial leg bone (shin)
- Proximal condyles articulate with the femur and fibula
- Tibial tuberosity for muscle attachment
- Distal end articulates with the talus and fibula and forms malleolus
Fibula
- Articulates proximally and distally with the tibia
- Not a weight bearing bone
- Helps stabilizes the ankle
Foot
- Made of tarsus, metatarsus, and phalanges
- Supports the body
- Acts as a lever to propel you forward in motion
- Arch designed to give when weight is applied
Tarsus
- 7 short bones
- talus articulates with the tibia and
fibula - calcaneous forms the heal (the Achilles tendon of the calf muscles attach to it)
Metatarsus
- 5 long bones
- numbered I - V medial to lateral
Phalanges
3 long bones in each, except the hallux (big toe)
