Holes Essentials of Human Anatomy Physiology Tenth Edition

Hole’s Essentials of Human Anatomy & Physiology Tenth Edition Chapter 7 Skeletal System Anatomy Part I

The Skeleton

Bone Markings · Surface features of bones · Sites of attachments for muscles, tendons, and ligaments · Passages for nerves and blood vessels · Categories of bone markings · Projections and processes – grow out from the bone surface · Depressions or cavities – indentations

The Axial Skeleton 80 bones · Skull including cranium (8) and facial (14) bones · Vertebral column including vertebrae (26) bones · Bony thorax including ribs (24) and sternum (1) · Hyoid bone singleton bone (1) · Middle ear bones including malleus (2), incus (2) and stapes (2)

The Skull · Two sets of bones · Cranium · Encloses brain tissue & protects the brain; surface allows for muscle attachment; some bones lined with sinuses · Composed of 8 flat bones: 4 single; 2 paired (parietal and temporal) · Facial bones · Composed of 14 bones: 6 paired; 2 single (mandible and vomer) · Hold eyes in anterior position and allow for facial expression · 13 of the 14 facial bones are joined by immovable sutures · Sutures are interlocking, immobile joints · Only the mandible is attached by a freely movable joint held to the rest of the skull by ligaments Slide 7. 6 b

The Skull · Cranium Frontal bone (1) · Forms anterior portion of the skull above the eyes · Upper margin of each orbit is marked by a supraorbital foramen (or supraorbital notch in some skulls) for blood vessels and nerves to pass to the tissues of the forehead (lower margin= infraorbital foramen) · Contain the frontal sinuses, one above each eye near the midline · Fuse with the parietal bones to form the coronal suture Parietal bones (2) · Located on each side of the skull just behind the frontal bone · Form the bulging sides and roof of the cranium · Fuse at midline along the sagittal suture and meet the frontal bone along the coronal suture Slide 7. 6 c

The Skull · Cranium Occipital bone (1) · Form the back of the skull and base of the cranium · Large opening called the foramen magnum allows nerves to pass from the brain, which enter the vertebral canal to become the spinal cord · Rounded processes called occipital condyles are located at either side of the foramen magnum to articulate with the first cervical vertebra (atlas). · Fuse with the parietal bones along the lambdoid suture Slide 7. 6 d

The Skull · Cranium Temporal bone (2) · Form parts of the sides and base of the cranium · Located near the inferior margin is an opening, the external auditory meatus, which lead to parts of the ear · Rounded projections below the external auditory meatus anchor muscles of the head and neck (mastoid process) and tongue and pharynx (styloid process) · Joining the zygomatic bone of the face is the zygomatic process, forming the superior prominence of the arch of the cheek · Depressions called mandibular fossae articulate with the mandibular condyles · Openings in the temporal bone allow for blood vessels to bring blood to the brain (carotid canals) and return blood back to the heart (jugular foramen) · On each side of skull, the temporal bones join the parietal bones along the squamous suture Slide 7. 6 e

The Skull · Cranium Sphenoid bone (1) · Consists of a central part creating the base of the skull and two wing -like structures that extend laterally toward each side of the skull · It also helps to form the floors and sides of the orbits · Along the midline of this bone is an indention, the sella turcica, which houses the pituitary gland. · The sphenoid bone also houses two sphenoid sinuses · The foramen ovale allows the cranial nerve #5 to supply nerves to the chewing muscles of the face Slide 7. 6 f

The Skull · Cranium Ethmoid bone (1) · The ethmoid bone is located in front of the sphenoid bone · Two masses on either side of the nasal cavity joined horizontally by the cribriform plates · Central to the cribriform plates is a triangular process called the crista galli which attaches the dura mater of the brain to the skull · A perpendicular plate projects downward in the midline of the cribriform plates and forms most of the nasal septum · From the lateral portions of the ethmoid bone twoard the perpendicular plate are scroll-shaped plates called superior nasal conchae and middle nasal conchae · The ethmoid bone also houses many small air spaces called ethmoid sinuses Slide 7. 6 g

The Skull · Facial Bones Maxillae bones (2) · Form upper jaw · Portions of these bones comprise the anterior roof of the mouth (hard palate), floor of the orbits, sides and floor of nasal cavity, sockets of the upper teeth · Inside the maxillae are (maxillary sinuses), the largest of the sinuses, are lateral to the nasal cavity · The palatine process is the portion of the maxillae that grow together and fuse along the midline to form the anterior section of the hard palate · The inferior border of each maxillary bone projects downward to form the horse-shoe alveolar process and alveolar arch which hold teeth. Slide 7. 6 h

The Skull · Facial Bones Palatine bones (2) · L-shaped bones located behind the maxillae · Horizontal portions form the posterior section of the hard palate and floor of the nasal cavity · Perpendicular portions help form the lateral walls of the nasal cavity Zygomatic bones (2) · Form the prominences of the cheeks below and to the sides of the eyes · Form the lateral walls and floors of the orbits · Contain a temporal process, which extends to join the zygomatic process of the temporal bone, together forming the zygomatic arch Slide 7. 6 i

The Skull · Facial Bones Lacrimal bones (2) · Thin, scalelike structure in the medial wall of each orbit between the ethmoid bone and maxilla · Contains the tear duct Nasal bones (2) · Long, thin and nearly rectangular · Lie side-by-side and fuse at the midline to form the bridge of the nose Vomer bone (1) · Thin, flat bone located along the midline within the nasal cavity · Posteriorly, the vomer joins the perpendicular plate of the ethmoid bone, and together form the nasal septum Slide 7. 6 j

The Skull · Facial Bones Inferior nasal conchae bones (2) · Fragile, scroll-shaped bones attached to the lateral walls of the nasal cavity · Support mucous membranes within the nasal cavity Mandible bone (1) · Horizontal, horseshoe-shaped body with a flat portion, mandibular ramus, projecting upwards at each end · The mandibular ramus contains two process, a posterior mandibular condyle and an anterior cornoid process · A curved bar of bone on the superior border of the mandible form the alveolar arch, which holds hollow sockets that bear the lower teeth Slide 7. 6 k

Human Skull, Lateral View 8 cranium bones: frontal; parietal (2); temporal (2); occipital; sphenoid; & ethmoid Slide 7. 6 l

Human Skull, Anterior View 14 cranial bones: maxillae; palatine; zygomatic; lacrimal; nasal; vomer (1); inferior conchae; mandible (1) Slide 7. 6 m

Human Skull, Superior View Slide 7. 6 n

Human Skull, Inferior View Slide 7. 6 o

The Hyoid Bone · The only bone that does not articulate with another bone · Suspended in midneck; anchored to styloid process of temporal bone · Serves as a moveable base for the tongue Slide 7. 6 r

Paranasal Sinuses · Air-filled, hollow portion of skull bones · Lined with mucous membranes and connected by passageways to the nasal cavity · Paranasal sinuses function to lighten the skull and give resonance and amplification to voice Slide 7. 6 p

Infantile Skull Fontanels – fibrous membranes connecting the cranial bones at birth • Soft spots allow the brain to grow and convert to bone within 2 years • Become the sutures of the adult skull The infantile skull is large compared to the infants total body length • Fetal skull ~1/4 the length of the body • Adult skull ~1/8 the length of the body The infantile skull includes: • a small face with a prominent forehead and large orbits • A jaw and nasal cavity that are small • Incompletely formed sinuses • A frontal bone is in two parts Slide 7. 6 q

The Vertebral Column · Vertebrae separated by intervertebral discs · Flexible fibrocartilage that cushion vertebra and absorb shock · The spine has a normal curvature · Thoracic & Sacral curvature = Primary/Convex · Cervical & Lumbar curvature = Secondary/Concave · Abnormal curvature: · scoliosis (lateral curve) · kyphosis (excess cervical curve) · lordosis (excess lumbar curve) · Each vertebrae is given a name according to its location Slide 7. 7 a

Structure of a Typical Vertebrae • • Body: weight bearing portion Vertebral arch: formed by the pedicles, laminae and spinous processes Vertebral foramen: spinal cord canal Transverse process: lateral projections ligaments and muscles attach Spinous process: posterior projection ligaments and muscles attach Articular processes: (superior and inferior) articulation projections allowing for joints between vertebra Intervertebral foramina: provide passageways for spinal nerves Slide 7. 7 b

Specific Characteristics of Vertebrae CERVICAL • 7 total • Transverse processes have transverse foramina, passageways for arteries leading to the brain • 2 nd -5 th spinous process is bifid • Atlas, supports the head with superior facets that articulate with the occipital condyle • Axis, bears a tootlike dens (odontoid process) and lies in the ring of the atlas • The atlas pivots around the dens THORACIC • 12 total • Long spinous process, sloping downward • Facets on the sides of their bodies articulate with ribs • Bodies increase in size to bear increasing loads of weight LUMBAR • 5 total • Large, stronger bodies SACRUM • 5 fused bones in 1 COCCYX • 4 fused bones in 1 Slide 7. 7 c

Regional Characteristics of Vertebrae Slide 7. 7 d

Regional Characteristics of Vertebrae Slide 7. 7 e

The Bony Thorax (a. k. a. Thoracic Cage) · Forms a cage to protect major organs · Made-up of: · Sternum · Ribs · Thoracic vertebrae · Costal cartilage Slide 7. 8 a

The Appendicular Skeleton 126 bones · Limbs (appendages) · Pectoral girdle · Pelvic girdle Attach limbs to axial skeleton ·“Girdle” suggests a ring-shaped structure, but the pectoral girdle is incomplete on the posterior between the scapulae and the sternum separates its bones on the anterior. Slide 7. 9 a

The Pectoral (Shoulder) Girdle · Composed of two bones · Clavicle – collarbone · Slender, rodlike bones with elongated “S” shape. · Acts as a brace to hold arm away from thorax · Scapula – shoulder blade · Broad, triangular bones. Not directly attached to axial skeleton. Held in place by trunk muscles · These bones allow the upper limb to have exceptionally free movement (3 reasons) · Attached to axial skeleton only at sternoclavicular joint · Loose attachment of scapula · Shallow glenoid cavity (poor reinforcement of shoulder joint by ligaments) Slide 7. 9 b

Bones of the Pectoral Girdle Clavicle • Attached to manubrium (of sternum) and acromion (of scapula) • Acromial (lateral) end & Sternal (medial) end Slide 7. 9 c

Bones of the Pectoral Girdle Scapula 2 processes: • Acromion process: connects with clavicle; Coracoid process: muscle attachment • Suprascapular notch: passageway for nerves • 3 borders (lateral, medial & superior) • 3 angles (lateral, inferior & superior) • 2 fossa (supraspinous & infraspinous) • Glenoid cavity: socket that receives the head of the humerus • Spine Slide 7. 9 d

Bones of the Upper Limb · The arm is formed by a single bone · Humerus · Head: fits into glenoid cavity of scapula · Greater and lesser tubercle: pts of muscle attachment; Intertubercular groove between. · Deltoid tuberosity: pt of deltoid muscle attachment · Radial groove: pt of nerve · Lateral and medial epicondyles: flank coronoid fossa (anteriorly) and olecranon fossa (posteriorly). Fossa allow for ulnar processes to move freely. · Capitulum and Trochlea: articulation Slide 7. 10 a

Bones of the Upper Limb • The forearm has two bones • Ulna • Olecranon & Coronoid Processes fit into corresponding fossa on humerus • Trochelear notch articulates with trochea on humerus • Radius • Radial tuberosity: attachment point for biceps muscle • Two joints between radius and Ulna: proximal and distal radioulnar joints • Radius and Ulna connected by interosseous membrane Styloid Process Slide 7. 10 b

Bones of the Upper Limb · The hand · Carpals – wrist · 8 bones · Metacarpals – palm · 5 bones · Phalanges – fingers · 14 bones · Each finger has three bones (distal, middle and proximal) · The thumb has 2 bones (distal and proximal only) Slide 7. 10 c

Bones of the Pelvic Girdle · Consists of two hip bones (a. k. a. coxae or innominate bones), sacrum & coccyx to make up the pelvis · Composed of three pair of fused bones · Ilium “wings” · Ischium “sit bone” · Pubis · The total weight of the upper body rests on the pelvis · Provides attachment for lower limbs · Protects several organs · Internal Reproductive organs · Urinary bladder · Distal end of the large intestine Slide 7. 11 a

The Pelvis • Ilium connected with sacrum at the sacroiliac joint • Pubic bones connect in middle at symphysis pubis and form the pelvic arch • As the pubis curves posteriorly and inferiorly to join the ischium, the obturator foramen, the largest foramen in the skeleton, is formed. • True pelvis – surrounded by bone • False pelvis – superior to true pelvis; medial to flaring ilia Sacral promontory Obturator foramen Slide 7. 11 b

The Pelvis • Acetabulum: receives head of thigh bone Iliac fossa Allows passage of blood vessels and sciatic nerve to posterior leg Obturator foramen: Allows passage of blood vessels and nerves to anterior leg Slide 7. 11 c

Gender Differences of the Pelvic Girdle & Pelvic Cavity The female: • coxae are lighter, thinner, and have less obvious muscular attachments compared to males. • obturator foramina and acetabula are smaller and farther apart than those of a male. • pelvic cavity is wider in all diameters and is shorter, roomier and less funnel-shaped compared to males. • ischial spines and ischial tuberosities are greater than in a male. • sacrum is wider and the 1 st sacral vertebra projects forward to a lesser degree. • sacral curvature is bent more sharply posteriorly than in a male. • coccyx is more movable than that of a male. • pubic arch wider than 90 degrees Slide 7. 11 d

Bones of the Lower Limbs · Fovea capitis The thigh has one bone · Femur – thigh bone · Fovea capitis-pit on the head marking the attachment of a ligament · Two trochanters, greater and less, and gluteal tuberosity serve as muscle attachment points · Head articulates with acetabulum · Medial and lateral condyles articulate with tibia · Condyles separated by intercondylar notch on posterior and patellar surface on the anterior · The patella, kneecap, is located in a tendon that passes anteriorly over the knee. Slide 7. 12 a

· Bones of the Lower Limbs The leg has two bones · Tibia “shinbone” · Medial bone · Lateral and medial condyles articulate with femur · Patellar ligament attaches to tibial tuberosity · Medial malleolus forms the inner ankle and is an attachment for ligaments · On the lateral side is a depression articulating with the fibula · The distal end of the tibia articulates with the talus · Fibula · Lateral “stick” forming a proximal head and a distal lateral malleolus · No weight is placed on the fibula, nor does it articulate with the knee joint Slide 7. 12 b

Bones of the Lower Limbs · The foot · Made up of the ankle, the instep (sole) and toes. · Seven ankle (tarsal) bones · Tarsus – ankle, moves freely where it joins the tibia and fibula · Calcaneus – heel bone, located below the talus · Talus and Calcaneus bear most weight · Instep (metatarsus) – 5 Metatarsal bones form the sole of the foot; heads of metatarsals form ball of the foot · Toes – 14 phalanges Slide 7. 12 c