Anatomy Physiology Chapter 4 Axial Appendicular Skeletal Anatomy

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

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

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. n All but 1 of the bones of skull are joined by sutures (interlocking, immovable joints) – Mandible attached by a freely moving joint. n

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

n 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

6. 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 n 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 n

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 n Sternum: fusion of three bones • Manubrium • Body • Xiphoid Process

n 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 n 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 n Consists of: – Pectoral girdle – Arm bones – Pelvis • Formed of three fused bones – Ilium • Large, flared upper bone – Leg bones

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

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

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

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

Pelvic Girdle n Joins the legs to the body and protects organs n 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 n Made of femur, patella, tibia, fibula, ankle, and foot. n 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 n Tibia – Shinbone; joins to femur and bones of ankle n Fibula – Thinner than the tibia – On the lateral side of the leg

The Foot n 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 n Foot: 5 metatarsals n Toes: Each has 3 phalanges except big toe (only 2 phalanges)

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