module 2 lecture chp 8

appendicular skeleton

pectoral girdle - attaches upper limbs to the trunk

pelvic girdle - attaches the lower limbs to the trunk

upper and lower limbs differ in function - share the same structural plan

pectoral girdle

• CONSISTS OF THE CLAVICLE AND THE SCAPULA

• PECTORAL GIRDLES DO NOT QUITE ENCIRCLE THE BODY COMPLETELY

• PROVIDES ATTACHMENT FOR MANY MUSCLES THAT MOVE THE UPPER LIMB

• GIRDLE IS VERY LIGHT AND UPPER LIMBS ARE MOBILE

• ONLY CLAVICLE ARTICULATES WITH THE AXIAL SKELETON

• Scapula can move freely

• SOCKET OF THE SHOULDER JOINT (GLENOID CAVITY) IS SHALLOW

• Good for flexibility, bad for stability

clavicle

• PROVIDE ATTACHMENT FOR MUSCLES

• HOLD THE SCAPULAE AND ARMS LATERALLY

• TRANSMIT COMPRESSION FORCES FROM THE UPPER LIMBS TO THE AXIAL SKELETON

scapulae

• LIE ON THE DORSAL SURFACE OF THE RIB CAGE

• LOCATED BETWEEN RIBS 2–7

• HAVE THREE BORDERS

• SUPERIOR• MEDIAL (VERTEBRAL)

• LATERAL (AXILLARY)

• HAVE THREE ANGLES

• LATERAL, SUPERIOR, AND INFERIOR

upper limb

30 bones

interosseous membrane

• INTERCONNECTS RADIUS AND ULNA

ulna

• MAIN BONE RESPONSIBLE FOR FORMING THE ELBOW JOINT WITH THE HUMERUS

• HINGE JOINT ALLOWS FOREARM TO BEND ON ARM

• DISTAL END IS SEPARATED FROM CARPALS BY FIBROCARTILAGE

• PLAYS LITTLE TO NO ROLE IN HAND MOVEMENT

radius

 CONTRIBUTES HEAVILY TO THE WRIST JOINT

• DISTAL RADIUS ARTICULATES WITH CARPAL BONES

• WHEN RADIUS MOVES, THE HAND MOVES WITH IT

carpus

• GLIDING MOVEMENTS OCCUR BETWEEN CARPALS

pelvic girdle

• ATTACHES LOWER LIMBS TO THE SPINE

• SUPPORTS VISCERAL ORGANS

• ACETABULUM IS A DEEP CUP THAT HOLDS THE HEAD OF THE FEMUR

• LOWER LIMBS HAVE LESS FREEDOM OF MOVEMENT

• Are more stable than the arm

• CONSISTS OF PAIRED HIP BONES (COXAL BONES OR PELVIC BONE) AND THE SACRUM

• COXAL BONES UNITE ANTERIORLY WITH EACH OTHER AND ARTICULATE POSTERIORLY

WITH THE SACRUM

• CONSISTS OF THREE SEPARATE BONES IN CHILDHOOD

• ILIUM, ISCHIUM, AND PUBIS

• BONES FUSE, RETAIN SEPARATE NAMES TO REGIONS OF THE COXAL BONES

• ACETABULUM

• A DEEP HEMISPHERICAL SOCKET ON LATERAL PELVIC SURFACE

ilium

• LARGE, FLARING BONE

• FORMS THE SUPERIOR REGION OF THE COXAL BONE

• SITE OF ATTACHMENT FOR MANY MUSCLES

• ARTICULATION WITH THE SACRUM FORMS SACROILIAC JOINT

ischium

• FORMS POSTEROINFERIOR REGION OF THE COXAL BONE

• ANTERIORLY—JOINS THE PUBIS• ISCHIAL TUBEROSITIES

• ARE THE STRONGEST PART OF THE HIP BONE

pubis

• FORMS THE ANTERIOR REGION OF THE COXAL BONE

• LIES HORIZONTALLY IN ANATOMICAL POSITION

• PUBIC SYMPHYSIS

• THE TWO PUBIC BONES ARE JOINED BY FIBROCARTILAGE AT THE MIDLINE

• PUBIC ARCH—INFERIOR TO THE PUBIC SYMPHYSIS

• ANGLE HELPS DISTINGUISH MALE FROM FEMALE PELVIS

pelvic structure

• BONY PELVIS IS DIVIDED INTO TWO REGIONS

• FALSE (GREATER) PELVIS—BOUNDED BY ALAE OF THE ILIAC BONES

• TRUE (LESSER) PELVIS—INFERIOR TO PELVIC BRIM

• Forms a bowl containing the pelvic organs

Childbearing

• MALE AND FEMALE PELVES EXHIBIT DIFFERENCES

• FEMALE PELVIS IS WIDER, SHALLOWER, AND LIGHTER

• PELVIC INLET

• DELINEATED BY PELVIC BRIM

• LARGEST IN DIAMETER RIGHT TO LEFT

• PELVIC OUTLET

• INFERIOR MARGIN OF TRUE PELVIS

• LARGEST IN DIAMETER ANTEROPOSTERIORLY

Pelvic differences

• MAJOR DIFFERENCES BETWEEN MALE AND FEMALE PELVES

• FEMALE PELVIS IS ADAPTED FOR CHILDBEARING

• Pelvis is lighter, wider, and shallower than in the male

• Provides more room in the true pelvis

lower limb

• CARRIES THE ENTIRE WEIGHT OF THE ERECT BODY

• BONES OF LOWER LIMB ARE THICKER AND STRONGER THAN THOSE OF UPPER LIMB

tibia

Receives weight of the body from the femur

medial

 TIBIA ARTICULATES WITH FEMUR AT SUPERIOR END

• FORMS THE KNEE JOINT

• TIBIA ARTICULATES WITH TALUS AT THE INFERIOR END

• FORMS THE ANKLE JOINT

Interosseous membrane

• CONNECTS THE TIBIA AND FIBULA

foot functions

• SUPPORTS BODY WEIGHT

• ACTS AS A LEVER TO PROPEL BODY FORWARD WHEN WALKING

• SEGMENTATION MAKES FOOT PLIABLE AND ADAPTED TO UNEVEN GROUND

tarsus

• BODY WEIGHT IS BORNE PRIMARILY BY THE TALUS AND CALCANEUS

trochlea of the talus

site of articulation with the tibia