NOTES:

Skeletal Organization, continued

(Ch 5, part 3)

THORACIC CAGE

**The thoracic cage includes the ribs, thoracic vertebrae, sternum, and costal cartilages. It supports the pectoral girdle and upper limbs, protects the organs and soft tissues of the thoracic cavity, and functions in breathing.thoracic cavity, and functions in breathing.

THORACIC CAGE

� RIBS:

• 12 pairs of ribs attach to the 12 thoracic vertebrae

• costal cartilages of the TRUE RIBS join the sternum directly; those of the FALSE RIBSsternum directly; those of the FALSE RIBSjoin it indirectly or not at all.

• a typical rib has:

� a shaft

� a head

� tubercles that articulate with the vertebrae

THORACIC CAGE

� STERNUM:

• the sternum consists of a: MANUBRIUM, BODY, and XIPHOID PROCESS

• it articulates with the clavicles

PECTORAL GIRDLE

**The pectoral girdle is composed of two clavicles and two scapulae. It forms an incomplete ring that supports the upper limbs and provides attachments for muscles.**

PECTORAL GIRDLE

� CLAVICLES:

• clavicles are rodlike bones located between the manubrium and scapulae

• they hold the shoulders in place and provide • they hold the shoulders in place and provide attachments for muscles.

PECTORAL GIRDLE� SCAPULAE:

• the scapulae are broad, triangular bones

• they articulate with the humerus of each upper limb

and provide attachments for muscles

• prominent features of each scapulae are the:

� acromion process (forms tip of shoulder)� acromion process (forms tip of shoulder)

� coracoid process (curves toward clavicle)

acromion pr.

coracoid pr.

UPPER LIMB

**Bones of the upper limb provide the frameworks and attachments of muscles, and function muscles, and function in levers that move the limb and its parts.**

UPPER LIMB

� HUMERUS:

• the humerus extends from the scapula to the elbow

• it articulates with the radius and ulna at the elbowthe elbow

� RADIUS:

• located on the THUMB SIDE of the forearm between the elbow and the wrist

• it articulates with the humerus, ulna, and wrist

UPPER LIMB� ULNA:

• the ulna is longer than the radius

• it articulates with the radius laterally and with a disc of fibrocartilage inferiorly

� WRIST and HAND:

• wrist is composed of 8 carpal bones (see • wrist is composed of 8 carpal bones (see bone list and bone diagrams/coloring)

• the hand includes 5 metacarpal bonesand 14 phalanges

• each finger has a: proximal, middle, and distal phalanx (except the thumb, which lacks a middle phalanx)

PELVIC GIRDLE

**The pelvic girdle consists of 2 COXAE that articulate with each other anteriorly and with the SACRUM posteriorly.**

PELVIC GIRDLE

� PELVIS:

• the SACRUM, COCCYX, and PELVIC GIRDLE form the bowl-shaped pelvis

PELVIC GIRDLE

� COXAE:

• each coxa consists of an ILIUM, ISCHIUM, and

PUBIS, which are fused together

*ILIUM: -largest portion of the coxa;

-joins the sacrum at the sacroiliac joint-joins the sacrum at the sacroiliac joint

*ISCHIUM:-lowest portion of the coxa;

-supports body weight when sitting

*PUBIS: -the anterior portion of the coxa;

-the pubic bones are fused anteriorly at

the SYMPHISIS PUBIS

LOWER LIMB

**Bones of the lower limb provide frameworks for the thigh, leg, ankle, and foot.**

LOWER LIMB� FEMUR:

• the femur extends from the hip to the knee

• the PATELLA articulates with the femur’s anterior surface

LOWER LIMB� TIBIA:

• located on the medial side of the lower

leg

• articulates with the TALUS• articulates with the TALUSof the ankle

� FIBULA:

• located on the lateral side of the tibia

• articulates with the ankle but does not

bear body weight

LOWER LIMB� ANKLE and FOOT:

• the ankle and foot consist of the 7 tarsals (see bone list and diagrams/coloring),

5 metatarsals, and 14 phalangesphalanges

• each toe has a: proximal, middle, and distal phalanx(except the “big toe”, which lacks a middle phalanx)