THE SKELETAL SYSTEM: THE APPENDICULAR SKELETON

The Pectoral Girdle(Shoulder)

2 pectoral girdles attach bones of upper limbs to axial

skeleton each: 1 clavicle 1 scapula

Clavicle

S-shaped, (medial ½ convex anteriorly, lateral ½ concave anteriorly) slender bone

lies horizontally across anterior thorax superior to 1st rib

Clavicle

medial end = sternal end is rounded & articulates with the manubrium @ sternoclavicular joint

Clavicle

lateral end = acromial end is flat articulates with acromion of the

scapula to form acromialclavicular joint

Clavicle

last bone to stop growing 1 of most frequently fx’d bones (2

curves) usually from fall on outstretched arm

or see compression fx in auto accidents from shoulder strap which can cause damage to median n. (between clavicle & 2nd rib)

Scapula

aka shoulder blade, angel bone large, triangular, flat bone in superior part of posterior thorax

between levels of 2nd & 7th ribs

spine: prominent ridge that runs diagonally across posterior surface

lateral edge: acromion a flattened expanded process, easily felt as hi pt of shoulder (tailors use it as landmark to measure length of arm)

glenoid cavity: inferior to acromion, smooth, shallow depression that accepts head of humerus in shoulder joint

Scapula

Upper Limb

6 parts:1. Humerus2. Ulna3. Radius4. Carpals5. Metacarpals 6. Phalanges

Joints: Shoulder Elbow Wrist Hand

Humerus

longest & largest bone of upper limb

articulates proximally with scapula & distally with ulna & radius

head: rounded proximal end articulates with glenoid cavity of scapula to form glenohumeral joint

Humerus

Humerus

distal end: capitulum: rounded knob on lateral

aspect that articulates with head of radius

trochlea: medial to capitulum, spool-shaped, articulates with ulna

Humerus

Ulna

medial aspect of forearm longer than radius proximal end: olecranon

(prominence in elbow) distal end: head, styloid process

(posterior)

Radius

lateral aspect of forearm

proximal end: head of radius: articulates with capitulum

distal end: styloid process (palpable proximal to thumb)

Ulna & Radius

connect @ 3 places

1. interosseous membrane

2. proximal end3. distal end

Carpals

proximal to the hand, distal to radius & ulna

8 small bones joined by ligaments

articulations w/each other called intercarpal joints

Carpal Tunnel

Metacarpals

Phalanges

14 bones of the digits (each hand) #’d I to V beginning with thumb thumb is the pollex has only 2

phalanges, other digits have 3 joints between phalanges called

interphalangeal joints

Phalanges

Pelvic Girdle

2 hip bones (os coxa) which unite anteriorly at pubic symphysis and posteriorly with the sacrum @ sacroiliac joint

Pelvic Girdle

Functions: provides sturdy

support for vertebral column

connects lower limb to axial skeleton

Newborn Pelvis

3 bones on each side:

1. Ilium superior

2. Pubis anterior &

inferior

3. Ischium posterior &

inferior

Ilium

largest of the 3 hip bones distinguishing features:1. Iliac Crest along superior surface1. Sacroiliac Joint (SI Joint) between sacrum and ilium

Ilium

Ischium

ramus of ischium fuses with pubis distinguishing features:

1. Ischial Tuberosity what you feel when someone sits

on your lap

Ischium

Pubis

Acetabulum formed by ilium, ischium, & pubis is the “socket” half of the hip joint

Pubic Symphysis joint between the 2 hip bones

True Pelvis/ False Pelvis

Pelvic Brim: line that distinguishes between true & false palvis

Male Pelvis

generally male bone heavier & stronger & have larger surface marker (because larger muscles attach)

Pelvis: deeper false pelvis, smaller, narrower pelvic brim heart-shaped acetabulum larger, faces posterior obturator foramen round

Female Pelvis

generally bones lighter & thinner Pelvis:

false pelvis shallow, widers pelvic brim larger, more oval acetabulum smaller & faces anterior obturator foramen oval

Male or Female?

Male or Female?

Lower Limb

30 bones in each: 1 femur 1 patella 1 tibia 1 fibula 7 tarsals 5 metatarsals 14 phalanges

Femur

longest, heaviest, & strongest bone in the body

proximally articulates with the acetabulum to form hip joint Head of the Femur: “ball” part of joint

small, central depression: fovea capitis Greater Trochanter

prominence felt & seen @ side of hip

Femur

Femur

distally articulates with: Patella Tibia

Patella (kneecap)

small, triangular, sesamoid bone develops in tendon of quadriceps

femoris muscle Parts: Base: broad, superior end Apex: pointed, inferior end

Patella

Tibia

“shin bone”larger, medial, weight-bearing bone

of lower legproximally articulates with femur &

fibuladistally articulates with fibula &

tarsals

Tibia

medial malleolus forms prominence that is palpable & visible on medial ankle

Fibula

parallel & lateral to the tibia & considerably smaller

head of fibula on proximal end

lateral malleolus at distal end

Tibia & Fibula

Tarsals

7 bones: 1 calcaneous: heel bone, largest of

the tarsals

Metatarsals

5 bones between tarsals & phalanges

#’d I to V from medial lateral

Phalanges

14 bones that make up the 5 digits #’d I to V medial to lateral Hallux: great or big toe has 2 large

heavy phalanges

Arches of the Foot

2 arches in foot: 1. allows the foot to support weight

of body by distributing weight over the soft & hard tissues

2. provide leverage while walkingfully developed by age 12 - 13

Arches of the Foot

2 longitudinal arches (medial & lateral

1 transverse arch