Biology 210 Chapter 8: Skeletal Tissues Supplement 1 By John McGill Material contributed by Beth Wyatt & Jack Bagwell DIVISIONS OF THE SKELETAL SYSTEM AXIAL SKELETON (80 BONES) Bones of the Head, Neck, and Torso APPENDICULAR SKELETON (126 BONES) Bones of the Upper and Lower Extremeties * Total Number of Major Bones in the Body = 206 BONES OF THE AXIAL SKELETON SKULL 28 Bones 1
CRANIAL BONES 8 Form the Cranium Surrounds the Brain FRONTAL-1 Anterior Forms Anterior Portion of Cranium (Forehead) & Anterior Cranial Floor & Forms Roofs of Orbits (Eye Sockets) PARIETAL - 2 Superior Forms Superior Portion of Cranium 2
TEMPORAL - 2 Lateral Forms Lateral Portion of Cranium & Cranial Floor OCCIPITAL - 1 Posterior Forms Posterior Portion of Cranium & Cranial Floor SPHENOID - 1 Central Forms Central Portion of Cranial Floor Shape Resembles Bat Known as the Keystone of the Cranium B/C the Sphenoid Bone Anchors All the Other Cranial Bones Lateral Forms Lateral Walls of Cranium Lies in Front of Temporal Bone & Lateral Walls of Orbits 3
ETHMOID - 1 Complex, Irregularly Shaped Bone General Location: Between Nasal and Sphenoid Bones ETHMOID - continued ETHMOID - continued Where the Ethmoid Bone Can Be Seen in an Articulated Skull: Medial Walls of Orbits Upper Portion of Nasal Septum Upper "Ledges" Projecting into the Nasal Cavities Anterior Cranial Floor 4
ETHMOID - continued Ethmoid sinuses associated with ethmoid bone hollow spaces inside ethmoid bone BONES OF THE AXIAL SKELETON SKULL FACIAL BONES Primarily Form the Face NASAL - 2 Form Bridge of Nose 5
MAXILLARY (MAXILLA) - 2 Upper Jawbones Form the central portion of the face "Keystone of the Face Anchors All Other Facial Bones Except Mandible Also Forms: Floor of Orbits & Anterior Portion (Most) of Hard Palate BONES OF THE AXIAL SKELETON SKULL FACIAL BONES ZYGOMATIC - 2 Cheekbones Also Form Lateral Walls of Orbits 6
MANDIBLE - 1 Lower Jawbone Largest, Strongest Bone of the Face LACRIMAL - 2 Forms Medial Walls of Orbits B/T the Maxillary and Ethmoid Bones Paper Thin Bones Usually Broken in Real Bone Skulls PALATINE - 2 Shaped like 2 L's facing one another Horizontal Portion of L's Forms Posterior Portion of Hard Palate Vertical Portion of L's Forms Lateral, Posterior Walls of Nasal Cavities 7
Palatine Bones Turbinates INFERIOR TURBINATES (CONCHAE) - 2 Form Lower "Ledges" That Project into Nasal Cavities Scroll-Shaped Inferior turbinate (IT) Middle turbinate (MT) Increase the surface area of the lining of the nose Warms, humidifies, & cleans air U=uvula T=anterior tongue BoT=base of tongue See next slide too Turbinates 8
VOMER - 1 Forms Lower Portion of Nasal Septum VOMER - 1 BONES OF THE EAR (6) Tiny Bones Located Within Temporal Bones In Middle Ear 3/Ear MALLEUS (2) INCUS (2) STAPES (2) 9
HYOID BONE (1) U Shaped Bone That Lies in the Neck B/T Mandible and Larynx The Only Bone in the Body That Doesn t Form a Joint With Another Bone Held in Place By Ligaments and Muscles Supports and Provides Muscle Attachment For Muscles That Form Floor of Mouth and Tongue HYOID BONE (1) BONES OF THE AXIAL SKELETON SPINAL (VERTEBRAL) COLUMN (26) 10
CERVICAL VERTEBRAE 7 ATLAS 1st Cervical Vertebra Named For Atlas in Greek Mythology AXIS 2nd Cervical Vertebra Named B/C Atlas Pivots Around Axis 11
THORACIC VERTEBRAE 12 LUMBAR VERTEBRAE 5 SACRUM 5 FUSED INTO 1 Wedge-Shaped Bone Consists of 5 Separate Vertebrae (Childhood) That Fuse Into 1 After Bones Mature 12
COCCYX 4 OR 5 FUSED INTO 1 Tailbone Consists of Separate Vetebrae That Fuse (Like Sacrum) BONES OF THE AXIAL SKELETON STERNUM AND RIBS (25) STERNUM 1 Breastbone Dagger-Shaped Flat Bone 13
RIBS 12 PAIR TRUE RIBS 7 PAIR Called True Ribs B/C They Attach Directly to the Sternum By Costal Cartilage FALSE RIBS 5 PAIR Called False Ribs B/C: 3 PAIR Attach Indirectly to the Sternum By the Costal Cartilage of Rib 7 (1st 3 Pair of False Ribs # s 8,9,10 Counting From the 1st True Rib) 2 PAIR Don t Attach to the Sternum At All (Last 2 Pair Of False Ribs, # s 11,12 Counting From the 1st True Rib) These Are Also Known as Floating Ribs STERNUM AND RIBS (25) continued Note: Posteriorly, ALL Ribs Are Attached to the Thoracic Vertebrae Note: Thorax (Thoracic Cage) = Sternum + Ribs + Vertebral Column, (Creates a Complete Boney Cage) BONES OF THE APPENDICULAR SKELETON UPPER EXTREMITIES (64) 14
CLAVICLE 2 Collarbone SCAPULA 2 Shoulder Blade Shoulder Girdle Shoulder Girdle = Clavicle + Scapula 15
HUMERUS 2 Long Bone of the Upper Arm RADIUS 2 Radius and Ulna Are Bones of the Forearm Radius: Thumb Side, Ulna: Little Finger Side ULNA 2 Radius and Ulna Are Bones of the Forearm Radius: Thumb Side, Ulna: Little Finger Side 16
CARPALS 16 Bones of the Anatomical Wrist Proximal End of Hand METACARPALS 10 Bones That Form the Palm of the Hand Knuckles = Heads of Metacarpals PHALANGES 28 Bones of the Fingers 3 in Each Finger, 2 in Each Thumb 17
BONES OF THE APPENDICULAR SKELETON LOWER EXTREMITIES (62) OS COXAE (COXAL/INNOMINATE) 2 (PELVIC GIRDLE) Pelvic/Hip Bones Broadest Bone in the Body Os Coxae (2) + Sacrum + Coccyx, Forms Complete Boney Ring FEMUR 2 Thigh Bone Longest, Largest, Strongest Bone 18
PATELLA 2 Kneecap TIBIA 2 Tibia and Fibula Are Bones of the Lower Leg Tibia: Shin Bone Larger, More Medial and More Superficial Compared to Fibula FIBULA 2 19
TARSALS 14 Bones That Form the Heel and the Posterior Portion of the Foot METATARSALS 10 Bones That Form the Long Portion of the Foot PHALANGES 28 Bones of the Toes; 3 in Each Toe Except Big Toes, 2 in Each Big Toe 20