THE AXIAL SKELETON
CONTAINS THE BONES FORMING THE AXIS
( The axis is the central line around which the parts of a thing, system are evenly arranged )
80 BONES
SKULL - 8 CRANIAL BONES AND 14 FACIAL BONES. ALSO 7 ASSOCIATED BONES ( 6 auditory ossicles and Hyoid bone )
BONES OF THE THORAX STERNUM AND 24 RIBS
VERTEBRAL COLUMN 24 VERTEBRAE, SACRUM AND COCCYX
FUNCTIONS
FRAMEWORK THAT SUPPORTS AND PROTECTS ORGANS IN THE DORSAL AND VENTRAL CAVITIES.
SURFACE FOR THE ATTACHMENT OF MUSCLES
THE JOINTS IN THE AXIAL SKELETON ARE VERY STRONG AND PERMIT LIMITED MOVEMENT
THE SKULL ( CRANIUM )
THE BONES OF SKULL PROTECT AND ENCLOSE THE BRAIN ( CRANIAL BONES )
AND FORM OUR FACIAL STRUCTURE ( FACIAL BONES )
BONES OF THE CRANIUM ARE ATTACHED TO EACH OTHER VIA SUTURES ( IMMOVABLE JOINTS )
( Except for the mandible-cranium joint )
FRONTAL BONE ( 1 )
EXTENDS FROM THE FOREHEAD TO THE CORONAL SUTURE.
ARTICULATE WITH A PAIR OF PARIETAL BONES.
PARIETAL BONES ( 2 )
FORM THE SUPERIOR PORTION OF THE SIDES OF OUR HEADS.
ARE JOINED SUPERIORLY BY THE SAGITTAL SUTURE
TEMPORAL BONES ( 2 )
FORM THE INFERIOR PORTION OF THE SIDES OF OUR HEADS.
VERY IRREGULAR IN SHAPE
HAS 4 IMPORTANT STRUCTURES ( Zygomatic process, External auditory meatus, Stiloid process and Mastoid process ).
ARTICULATES WITH PARIETAL BONE AT THE SQUAMOSAL SUTURE
OCCIPITAL BONE ( 1 )
FORMS THE POSTERIOR PORTION OF THE BACK OF YOUR HEAD.
MEETS THE PARIETALS AT THE LAMBDOIDAL SUTURE
TWO IMPORTANT STRUCTURES ARE THE FORAMEN MAGNUM AND THE OCCIPITAL CONDYLES.
SPHENOID BONE ( 1 )
UNDERNEATH THE FRONTAL BONE
HAS THE SELLA TURCICA
ETHMOID BONE ( 1 )
SMALL, RECTANGULAR BONE DEEP IN THE EYE ORBIT, BEHIND THE BRIDGE OF THE NOSE.
THE FACIAL BONES
SUPERFICIAL FACIAL BONES Provides areas for the attachment of muscles that control facial expressions ( including chewing )
DEEPER FACIAL BONES Separates oral and nasal cavities. Help to form the Nasal septum
CONSISTS OF THIRTEEN BONES FUSED TOGETHER, AND A MOVABLE MANDIBLE.
ONLY ONE BONE, THE VOMER, IS NOT PAIRED
THE NASAL BONES ARE SMALL BONES THAT FORM THE BRIDGE OF THE NOSE, LATERAL TO THE NASALS ARE THE MAXILLARY BONES.
BELOW THE EYE ORBITS ARE THE ZYGOMATIC BONES (cheek bones).
AT THE BRIDGE OF THE NOSE, LATERAL TO EACH MAXILLA ARE THE SMALL LACRIMAL BONES
THE INFERIOR NASAL CONCHAE ARE THE LOWER SHELVES OF BONE IN THE NASAL CAVITY. THE OTHER CONCHAE IN THE NASAL CAVITY ARE PART OF THE MAXILLA
THE LOWER JAW BONE IS THE MANDIBLE
IF WE TURN THE SKULL OVER TO VIEW THE INFERIOR SURFACE WE CAN LOCATE THE PALATINE BONES OF THE POSTERIOR ROOF OF THE MOUTH NEXT TO THE LAST MOLAR TOOTH
THE NASAL CAVITY IS DIVIDED BY A THIN WALL OF BONE, THE VOMER
SINUSES OF THE SKULL
SKULL CONTAINS FOUR CAVITIES CALLED PARANASAL SINUSES WHICH INTERCONNECT WITH THE NASAL CAVITY AND
REDUCE THE WEIGHT OF THE SKULL
THE SINUES ARE NAMED AFTER THE BONES IN WHICH ARE SITUATED
FRONTAL SINUS
SPHENOID SINUS
ETHMOID SINUS
MAXILLARY SINUS
HYOID BONE
AN UNUSUAL BONE BECAUSE IT DOES NOT ARTICULATE WITH ANY OTHER BONES.
IT IS LOCATED IN THE NECK, ABOVE LARYNX
SERVES AS THE BASE OF TONGUE, AND AS AN ATTACHMENT FOR NECK MUSCLES
SUTURES
CORONAL SUTURE
LAMBOIDAL SUTURE
SAGGITAL SUTURE
SQUAMOUS SUTURE
CORONAL SUTURE
WHERE THE FRONTAL BONE MEETS THE PARIETAL BONES ANTERIORLY
LAMBOIDAL SUTURE
WHERE THE OCCIPITAL BONE MEETS THE PARIETAL BONES POSTERIORLY
SAGGITAL SUTURE
SAME AS THE SAGGITAL SECTION ( DIVIDES THE BODY INTO RIGHT AND LEFT PORTIONS )
IS WHERE THE PARIETAL BONES MEET AT THE TOP OF THE SKULL.
EXTENDS FROM LAMBOIDAL TO CORONAL SUTURES
SQUAMOUS SUTURE
WHERE THE TEMPORAL BONES MEET THE PARIETAL BONES ON THE SIDE OF THE HEAD
FETAL SKULL
HAS MANY BONES THAT ARE UNFUSED AND INCOMPLETELY OSSIFIED
THE UNOSSIFIED MEMBRANOUS AREAS ARE CALLED FONTANELS
FONTANELS OSSIFY BY THE TIME THE BABY IS 2 YEARS OLD
VERTEBRAL COLUMN
CONSISTS 0F 33 BONES INTRICATELY LINKED TOGETHER TO ALLOW FOR MAXIMUM STRENGHT, FLEXIBILITY, AND PROTECTION.
VERTEBRAE ARE CONNECTED TO EACH OTHER VIA LIGAMENTS.
IT ARTICULATES WITH THE SKULL SUPERIORLY, THE PELVIC GIRDLE INFERIORLY, AND THE RIBS LATERALLY
BETWEEN EACH VERTEBRA IS AN INTERVERTEBRAL DISC
VERTEBRAE ARE GROUPED INTO..
7 CERVICAL VERTEBRAE
12 THORACIC VERTEBRAE
5 LUMBAR VERTEBRAE
SACRUM ( 5 fused vertebrae )
COCCYX ( 3-5 fused vertebrae )
VERTEBRAL COLUMN IS NOT STRAIGHT AND RIGID..
IN A LATERAL VIEW WE CAN SEE FOUR SPINAL CURVES:
CERVICAL
THORACIC
LUMBAR
SACRAL
ABNORMAL DISTORTIONS OF SPINAL CURVATURES
KYPHOSIS - exaggerated thoracic curvature
LORDOSIS exaggerated lumbar curvature
SCOLIOSIS abnormal lateral curvature
VERTEBRAL ANATOMY
VERTEBRAL BODY THICK, DISC-SHAPED ANTERIOR PORTION.
SPINOUS PROCESS LONG, SINGLE EXTENSION OF POSTERIOR VERTEBRAL WALL
TRANSVERSE PROCESS A PAIR OF EXTENSIONS LATERAL TO SPINOUS
VERTEBRAL FORAMEN LARGE HOLE, POSTERIOR TO THE BODY
PEDICLE STRUT OF BONE EXTENDING POSTERIORLY FROM BODY TO A TRANSVERSE PROCESS
LAMINA FLAT PLATE OF BONE BETWEEN TRANSVERSE AND SPINOUS PROCESS
ARTICULAR PROCESSES INFERIOR AND SUPERIOR, ARTICULATE WITH THE ARTICULAR FACETS
ARTICULAR FACET INFERIOR AND SUPERIOR, ARTICULATE WITH THE ARTICULAR PROCESSES.
CERVICAL VERTEBRAE
SMALLER, LIGHTER AND MORE DELICATE THAN VERTEBRAE IN LOWER REGIONS
THE TOP TWO ARE SPECIALIZED TO ALLOW HEAD MOVEMENT.
THEY HAVE TRANSVERSE FORAMEN
THE ATLAS ( C 1 ) ARTICULATES WITH OCCIPITAL CONDYLES OF THE SKULL.
THE AXIS ( C 2 ) HAS A PROJECTION WHICH EXTENDS UP AND THROUGH THE MIDDLE OF THE AXIS. IS A PIVOT POINT AROUND WHICH HEAD ROTATES.
WE DON΄T HAVE INTERVERTEBRAL DISC BETWEEN C1 AND C2.
THORACIC VERTEBRAE
LARGER THAN CERVICAL VERTEBRAE
ARTICULATE WITH THE RIBS
LUMBAR VERTEBRAE
ARE LARGER THAN THE OTHER BECAUSE THEY CARRY A LARGER QUANTITY OF WEIGHT THAN THE OTHER VERTEBRAE.
VERTEBRAL FORAMEN IS SMALLER THAN THORACIC VERTEBRAE.
SACRUM
5 FUSED VERTEBRAE WHICH STREGTHEN AND STABILIZED THE PELVIS
PROTECTS REPRODUCTIVE, DIGESTIVE AND URINARY ORGANS.
ARTICULATES WITH THE ILIUM
COCCYX
OUR VESTIGUAL TAILBONE
3-5 FUSED VERTEBRAE
ESSENTIALLY USELESS IN THE HUMAN!!!
BONES OF THE THORAX
CONSISTS OF THE THORACIC VERTEBRAE, THE RIBS AND THE STERNUM
PROTECTS HEART, LUNGS, THYMUS
SERVES AS AN ATTACHMENT POINT FOR MUSCLES INVOLVED IN RESPIRATION, POSITION OF VERTEBRAL COLUMN AND MOVEMENT OF PECTORAL GIRDLE
STERNUM
FLAT BONE THAT FORMS IN THE ANTERIOR MIDLINE OF THE THORACIC WALL
IS COMPOSED OF THREE BONY ELEMENTS: MANUBRIUM, BODY, AND XIPHOID PROCESS
MANUBRIUM
ARTICULATES WITH THE CLAVICLES AND THE CARTILAGES OF THE FIRST PAIR OF RIBS
BODY
ATTACHES TO THE INFERIOR SURFACE OF THE MANUBRIUM AND EXTENDS INFERIORLY ALONG THE MIDLINE
INDIVIDUAL COSTAL CARTILAGES FROM RIBS PAIRS 2 7 ARE ATTACHED TO THIS PORTION
XYPHOID PROCESS
SMALLEST PART OF THE STERNUM
ATTACHED TO THE INFERIOR SURFACE OF THE BODY
THE DIAPHRAGM AND RECTUS ABDOMINALIS MUSCLES ATTACH TO THE XYPHOID PROCESS
RIBS
12 PAIRS OF RIBS PROTECTS THE THORACIC ORGANS AND AID IN RESPIRATION
ALSO CALLED COSTAE
ARE CLASSIFIED ACCORDING TO HOW ARTICULATE WITH THE STERNUM
VERTEBROESTERNAL RIBS
THE SUPERIOR 7 PAIRS ARE KNOW AS TRUE RIBS
BECAUSE THER ARTICULATE DIRECTLY WITH THE STERNUM BY SEPARATE CARTILAGINOUS EXTENSIONS
( COSTAL CARTILAGES
VERTEBROCHONDRAL RIBS
THE PAIRS 8 12 ARE KNOW AS THE FALSE RIBS
BECAUSE THEIR ANTERIOR ATTACHMENT IS AN INDIRECT ONE.
THE COSTAL CARTILAGE OF THESE RIBS FUSE TOGETHER AND MERGE WITH THE CARTILAGES OF RIB PAIR 7
THE LAST TWO PAIRS ARE KNOW AS FLOATING RIBS
AND HAVE NO CONNECTION WITH STERNUM
( are attached only to vertebrae )