Chapter 7: The Skeletal System: The Axial Skeleton

Transcription

1 Chapter 7: The Skeletal System: The Axial Skeleto

2 The Skeletal System: The Axial Skeleto Chapter 7 Divisios of the Skeletal System Types of Boes Boe Surface Markigs Skull Hyoid Boe Vertebral Colum Thorax

3 Divisios of the Skeletal System The huma skeleto cosists of 206 amed boes Boes of the skeleto are grouped ito two pricipal divisios: q q Axial skeleto Cosists of the boes that lie aroud the logitudial axis of the huma body Skull boes, auditory ossicles (ear boes), hyoid boe, ribs, sterum (breastboe), ad boes of the vertebral colum Appedicular skeleto Cosists of the boes of the upper ad lower limbs (extremities), plus the boes formig the girdles that coect the limbs to the axial skeleto

4 Divisios of the Skeletal System

5 Divisios of the Skeletal System

6 Types of Boes Boes ca be classified ito five types based o shape: Log Short Flat Irregular Sesamoid

7 Types of Boes Log Boes q Greater legth tha width ad are slightly curved for stregth q Femur, tibia, fibula, humerus, ula, radius, phalages Short boes q Cube-shaped ad are early equal i legth ad width q Carpal, tarsal Flat boes q Thi ad composed of two early parallel plates of compact boe tissue eclosig a layer of spogy boe tissue q Craial, sterum, ribs, scapulae Irregular boes q Complex shapes ad caot be grouped ito ay of the previous categories q Vertebrae, hip boes, some facial boes, calcaeus Sesamoid boes q Protect tedos from excessive wear ad tear q Patellae, foot, had Sutural boes q Small boes located i sutures of craial boes

8 Boe Surface Markigs Boes have characteristic surface markigs q Structural features adapted for specific fuctios There are two major types of surface markigs: q 1) Depressios ad opeigs Allow the passage of blood vessels ad erves or form joits q 2) Processes Projectios or outgrowths that form joits or serve as attachmet poits for ligamets ad tedos

9 Skull Skull (craium) Cosists of 22 boes Boes of the skull are grouped ito two categories: q q Craial boes Eight craial boes form the craial cavity q Frotal boe, two parietal boes, two temporal boes, the occipital boe, the spheoid boe, ethmoid boe Facial boes Fourtee facial boes form the face q Two asal boes, two maxillae, two zygomatic boes, the madible, two lacrimal boes, two palatie boes, two iferior asal cochae, vomer

10 Skull

11 Skull The craial ad facial boes protect ad support special sese orgas ad the brai Besides formig the large craial cavity, the skull also forms several smaller cavities q Nasal cavity q Orbits (eye sockets) q Paraasal siuses q Small cavities which house orgas ivolved i hearig ad equilibrium

12 Skull Immovable joits called sutures fuse most of the skull boes together The skull provides large areas of attachmet for muscles that move various parts of the head Skull ad facial boes provide attachmet for muscles that produce facial expressios The facial boes form the framework of the face ad provide support for the etraces to the digestive ad respiratory systems

13 Skull (Craial Boes) Frotal Boe q Forms the forehead Parietal Boes q Form the sides ad roof of the craial cavity Temporal Boes q Form the lateral aspects ad floor of the craium Occipital Boe q Forms the posterior part ad most of the base of the craium Spheoid Boe q Lies at the middle part of the base of the skull Ethmoid Boe q Located o the midlie i the aterior part of the craial floor medial to the orbits q A major superior supportig structure of the asal cavity q Cotai thi projectios called cochae which are lied by mucous membraes q Icreased surface area i the asal cavity helps to humidify ihaled air trappig ihaled particles

14 Skull

15 Skull

16 Skull

17 Skull (Facial Boes) Nasal Boes q Form the bridge of the ose Maxillae q q Form the upper jawboe Form most of the hard palate Separates the asal cavity from the oral cavity Zygomatic Boes q commoly called cheekboes, form the promieces of the cheeks Lacrimal Boes q Form a part of the medial wall of each orbit Palatie Boes q Form the posterior portio of the hard palate Iferior Nasal Cochae q Form a part of the iferior lateral wall of the asal cavity

18 Skull (Facial Boes) Vomer q Forms the iferior portio of the asal septum Madible q q q Lower jawboe The largest, strogest facial boe The oly movable skull boe Nasal Septum q q Divides the iterior of the asal cavity ito right ad left sides Broke ose, i most cases, refers to septal damage rather tha the asal boes themselves Orbits q Eye socket Foramia q Opeigs for blood vessels, erves, or ligamets of the skull

19 Skull

20 Skull

21

22 Skull

23 Skull

24 Skull

25 Skull

26 Skull Uique Features of the Skull q Sutures, Paraasal siuses, Fotaels Sutures q a immovable joit that holds most skull boes together Paraasal Siuses q Cavities withi craial ad facial boes ear the asal cavity q Secretios produced by the mucous membraes which lie the siuses, drai ito the asal cavity q Serve as resoatig chambers that itesify ad prolog souds Fotaels q Areas of uossified tissue q At birth, uossified tissue spaces, commoly called soft spots lik the craial boes q Evetually, they are replaced with boe to become sutures q Provide flexibility to the fetal skull, allowig the skull to chage shape as it passes through the birth caal

27 Skull

28 Skull

29 Hyoid Boe Does ot articulate with ay other boe Supports the togue, providig attachmet sites for some togue muscles ad for muscles of the eck ad pharyx The hyoid boe also helps to keep the laryx (voice box) ope at all times

30 Vertebral Colum Also called the spie, backboe, or spial colum Fuctios to: q Protect the spial cord q Support the head q Serve as a poit of attachmet for the ribs, pelvic girdle, ad muscles The vertebral colum is curved to varyig degrees i differet locatios q Curves icrease the colum stregth q Help maitai balace i the upright positio q Absorb shocks durig walkig, ad help protect the vertebrae from fracture

31 Vertebral Colum

32 Vertebral Colum Various coditios may exaggerate the ormal curves of the vertebral colum q Kyphosis q Lordosis q Scoliosis Composed of a series of boes called vertebrae (Adult=26) q 7 cervical are i the eck regio q 12 thoracic are posterior to the thoracic cavity q 5 lumbar support the lower back q 1 sacrum cosists of five fused sacral vertebrae q 1 coccyx cosists of four fused coccygeal vertebrae

33 Vertebral Colum

34 Vertebral Colum (Itervertebral Discs) Foud betwee the bodies of adjacet vertebrae Fuctios to: q Form strog joits q Permit various movemets of the vertebral colum q Absorb vertical shock Vertebrae typically cosist of: q A Body (weight bearig) q A vertebral arch (surrouds the spial cord) q Several processes (poits of attachmet for muscles)

35 Vertebral Colum

36 Vertebral Colum (Regios) Cervical Regio q Cervical vertebrae (C1 C7) q The atlas (C1) is the first cervical vertebra q The axis (C2) is the secod cervical vertebra Thoracic Regio q Thoracic vertebrae (T1 T12) q Articulate with the ribs Lumbar Regio q Lumbar vertebrae (L1 L5) q Provide for the attachmet of the large back muscles Sacrum q The sacrum is a triagular boe formed by the uio of five sacral vertebrae (S1 S5) q Serves as a strog foudatio for the pelvic girdle Coccyx q The coccyx, like the sacrum, is triagular i shape q It is formed by the fusio of usually four coccygeal vertebrae

37 Vertebral Colum

38 Vertebral Colum

39 Vertebral Colum

40 Vertebral Colum

41 Vertebral Colum

42 Thorax Thoracic cage is formed by the: q Sterum q Ribs q Costal cartilages q Thoracic vertebrae Fuctios to: q Eclose ad protect the orgas i the thoracic ad abdomial cavities q Provide support for the boes of the upper limbs q Play a role i breathig

43 Thorax Sterum q Breastboe located i the ceter of the thoracic wall q Cosists of the maubrium, body, xiphoid process Ribs q Twelve pairs of ribs give structural support to the sides of the thoracic cavity Costal cartilages q Costal cartilages cotribute to the elasticity of the thoracic cage

44 Vertebral Colum

45 Vertebral Colum