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 socket acromion 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 Limb The 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 –4 th and 5 th metatarsals Transverse Arch –Distal row of tarsals (talus, navicular, cuneiforms, calcaneous) –5 th metatarsals Fallen Arches- Flat feet –When ligaments and tendons holding bones together weaken