Chapter 4: Axial & Appendicular Skeletal Anatomy Waggy Anatomy & Physiology Chapter 4: Axial & Appendicular Skeletal Anatomy Waggy

Axial Skeleton Consists of: 1. Skull Eight cranial bones 14 bones of face 2. Thoracic Cage (Ribs & Sternum) 3. Spinal column

Skull Skull formed by 2 sets of bones 1. Cranium – encloses & protects brain. 2. Facial bones – holds eyes in anterior position & allows the facial muscles to show emotions. All but 1 of the bones of skull are joined by sutures (interlocking, immovable joints) Mandible attached by a freely moving joint.

1. Cranium Made up of 8 large flat bones 1. Frontal – forms forehead, brow bone, superior eye orbit 2&3 Parietal (2) – form most of the superior & lateral walls of the cranium Meet in midline = sagittal suture Meet frontal = coronal suture 4&5. Temporal (2) – inferior to parietals & join at the squamous sutures

Important bone markings found on temporal bones: External acoustic (auditory) meatus – canal leading to eardrum Styloid process - projection inferior to external auditory meatus Zygomatic process – thin bone that joins w/ the zygomatic (cheek) bone Mastoid process – rough projection posterior & inferior to the external auditory meatus Jugular foramen – junction of occipital & temporal; Allows for passage of jugular vein Internal auditory meatus – anterior to jugular foramen Carotid foramen - anterior to jugular foramen; Carotid artery runs through it to brain

Occipital – most posterior bone of cranium -Joins parietals anteriorly at lambdoidal suture -Foramen magnum - large opening in base of the occipitals (spinal cord connects with the brain) -Lateral to the foramen magnum are occipital condyles

7. Sphenoid – butterfly-shaped – spans the width of the skull and forms part of cranial cavity floor Sella turcica - small depression on the midline of the sphenoid, holds the pituitary gland Foramen ovale - large oval opening in line w/ the posterior end of the sella turcica Parts of the sphenoid form part of the eye orbits

8. Ethmoid – irregularly shaped, anterior to sphenoid – forms roof of nasal cavity and medial walls of the orbits. Crista galli -Cock’s comb = superior ethmoid surface projection – outermost brain covering attaches Cribriform plates – holey areas nerve fibers for smell pass through from nose

The 14 Facial Bones 12 paired, only the mandible and vomer are single 1&2. Maxillae (2) / maxillary bones – fused to form upper jaw Palatine processes- extensions that form the anterior part of the hard palate Paranasal Sinuses – drain the nasal passages, lighten the skull bones, amplify sounds as we speak Sinusitis (infection of sinuses) – can result in headache or upper jaw pain

Facial Bones 3&4. Palatine(2) – posterior to palatine processes of maxillae – form posterior part of hard palate cleft palate= failure of these to fuse 5&6. Zygomatic (2) – cheek bones 7&8. Lacrimal (2) – fingernail sized bones forming part of medial walls of orbits serves as passageway for tears 9&10. Nasal (2)–form bridge of nose – lower part of nose made of cartilage

Facial Bones 11. Vomer Plow(1) forms most of the nasal septum 12. Mandible (lower jaw) – largest, strongest bone of the face –only freely movable joints in the skull 13& 14. Inferior Nasal concha - air moves through these as breathing to warm, moisten & filter it before reaching lungs

Thoracic Cage Sternum: fusion of three bones Manubrium Body Xiphoid Process

Ribs: 12 pairs, grouped by structure True: 1-7 attach directly to sternum via cartilage False: 8-12 do not attach to sternum directly Vertebrochondral: 8-10, fused together by cartilage Floating:11-12, special type of false

Vertebral Column 24 vertebrae, sacrum and coccyx (26 total) Five regions 7 cervical 12 thoracic 5 lumbar Sacral: 5 fused bones Coccygeal:3 to five fused bones

Appendicular Skeleton Consists of: Pectoral girdle Arm bones Pelvis Formed of three fused bones Ilium Large, flared upper bone Leg bones

Pectoral Girdle Joins the arms to the body Made of 2 clavicles and 2 scapula

The Arm Made of the humerus (upper arm), radius, ulna (lower arm) and carpel bones (hand) Humerus -Joins the pectoral girdle at the scapula & joins the radius at the capitulum & the ulna at the trochlea

Lower Arm Radius Thumb side of the forearm Ulna Longer than the radius Pinkie side of forearm

The Hand Wrist: 8 carpel bones Hand: 5 metacarpels Fingers: 3 phalanges in each finger except the thumb (only 2 phalanges) total of 14 bones

Pelvic Girdle Joins the legs to the body and protects organs Each hip is made of 3 bones: ilium, ischium, and pubis Ilium: largest, superior portion of hip bone, joins to the sacrum Ischium: L shaped portion, supports weight when sitting Pubis: anterior portion of hip

The Leg Made of femur, patella, tibia, fibula, ankle, and foot. Femur: thighbone, longest and heaviest in body Joins to pelvis at acetabulum Joins with tibia at medial and lateral condyles Patella: covers tendon over knee

Lower Leg Tibia Fibula Shinbone; joins to femur and bones of ankle Thinner than the tibia On the lateral side of the leg

The Foot Ankle: made of 7 tarsal bones Talus: tarsal that joins with the tibia and fibula Calcaneus: heel bone, supports body weight, where Achilles tendon attaches Foot: 5 metatarsals Toes: Each has 3 phalanges except big toe (only 2 phalanges)

The End