NOTES part 4 : Skeletal Organization, continued

(Ch 7)

PECTORAL GIRDLE**The pectoral (or shoulder) 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 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)

Coracoid process (curves toward clavicle)

3. Glenoid cavity- arm socketacromion pr.

coracoid pr.

Glenoid cavity

UPPER LIMB

**Bones of the upper limb provide the framework and attachment for 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 elbow

• Bone markings on the humerus– Proximal epiphysis- head, – Diaphysis- deltoid tuberosity– Distal epiphysis- olecranon fossa,

coronoid fossa

UPPER LIMB ULNA:

• The ulna is longer than the radius

• It articulates with the radius laterally and with a disc of fibrocartilage inferiorly Bone Markings

• Olecranon process projects posteriorly• Coronoid process projects anteriorly

RADIUS:

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

• It articulates with the humerus, ulna, and wrist

WRIST and HAND:

• Wrist is composed of 8 carpal bones The pisiform is the only carpal visible from the

surface of the skin (projection under the pinky)

• The hand includes 5 metacarpal bones and 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.**

Coxal bone

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*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 (widens

during childbirth)*Acetabulum: - Hip socket

– Formed by union of ilium, ischium, and 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– Thigh bone– Longest and heaviest in the body– Proximal Epiphyseal Projections

• Head, neck, greater and lesser trochanters

Lower LimbThe PATELLA articulates with the femur’s

anterior surface– More commonly know as the kneecap

LOWER LIMB TIBIA:

• Located on the medial side of the lower

leg• Articulates with the TALUS of the ankle

Talus fits between medial malleolus of the tibia and lateral malleolus of the fibula

• Projections- tibial tuberosity, medial malleolus

FIBULA:

• Located on the lateral side of the tibia

• Articulates with the ankle but does not bear body weight– Projection-

lateral

malleolus

LOWER LIMB

ANKLE and FOOT:

• The ankle and foot consist of the 7 tarsals, 5 metatarsals, and 14 phalanges

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

• The foot is made of arches which make it more structurally sound

• Medial Longitudinal Arch– Tarsals- calcaneus, Talus, navicular, cuneiforms– First 3 metatarsals

• Lateral Longitudinal Arch– Tarsals- Calcaneous and cuboid– 4th and 5th metatarsals

• Transverse Arch– Distal row of tarsals (talus, navicular, cuneiforms,

calcaneous)– 5th metatarsals

• Fallen Arches- Flat feet– When ligaments and tendons holding bones together

weaken