THE SKELETAL SYSTEM THE APPENDICULAR SKELETON The Pectoral

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 1 st 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 & 2 nd rib)

Scapula aka shoulder blade, angel bone large, triangular, flat bone in superior part of posterior thorax between levels of 2 nd & 7 th 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 1. 2. 3. 4. 5. 6. 6 parts: Humerus Ulna Radius Carpals Metacarpals 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 1. 2. 3. connect @ 3 places interosseous membrane proximal end 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 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 1. 3 bones on each side: Ilium � 2. Pubis � 3. superior anterior & inferior Ischium posterior & inferior

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

Ilium

Ischium 1. ramus of ischium fuses with pubis distinguishing features: 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, � Greater central depression: fovea capitis 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 leg proximally articulates with femur & fibula distally 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 walking fully developed by age 12 - 13

Arches of the Foot 2 longitudinal arches (medial & lateral 1 transverse arch