The Appendicular Skeleton

The Appendicular Skeleton Composed of 126 bones Limbs (appendages) Pectoral girdle Pelvic girdle

The Appendicular Skeleton Figure 5.6a

The Pectoral (Shoulder) Girdle Composed of two bones Clavicle — collarbone Scapula — shoulder blade These bones allow the upper limb to have exceptionally free movement

Bones of the Shoulder Girdle Figure 5.21c–d

Clavicles Slender, rodlike bones with elongated S shapes Located at base of the neck and run horizontally between the sternum and the shoulders Sternal ends – articulate with the manubrium Acromial ends – articulate with the scapulae Brace the scapulae, holding the shoulders in place Structurally weak

Scapulae Broad, triangular bones located on either side of the upper back Spine – divides posterior surface 2 processes at the head: Acromion process – forms tip of the shoulder and articulates with the clavicle Coracoid process – curves anteriorly and inferiorly to the clavicle Glenoid cavity – between the acromion and coracoid processes; articulates with the head of the humerus Suprascapular notch – passage way for nerves

Upper Limb Bones Bones form the framework of the arm, forearm, and hand Bones function as levers for muscle contraction Includes: Humerus (2) Radius (2) Ulna (2) Carpals (16) Metacarpals (10) Phalanges (28)

Humerus Long bone that extends from scapula to the elbow Head fits into glenoid cavity of scapula Greater tubercle – on lateral side Lesser tubercle – on anterior side Surgical neck – tapering region below head and tubercles (common fracture site) Deltoid tuberosity – rough area near the middle of the shaft on the lateral side attachment site for the deltoid muscle

Humerus Bone Features continued… Coronoid fossa – process where the elbow bends: receives the ulna Capitulum – articulates with the radius Olecranon fossa – on posterior surface, receives the olecranon process of the ulna when the elbow straightens Trochlea – articulates with the ulna Epicondyles – attachments for elbow muscles and ligaments

Radius On thumb side of forearm Shorter than the ulna Extends from the elbow to the wrist and crosses over the ulna when hand is turned over at the wrist Radial tuberosity – process just below the head; attachment for the biceps Styloid process – attachment for wrist ligaments at the distal end

Ulna Longer than the radius Trochlear notch – at proximal end, wrench-like opening that articulates with the trochlea of the humerus Olecranon process – above the trochlear notch; attachment for triceps that straightens the upper limb at the elbow; fits into olecranon fossa Coronoid process – below trochlear notch, fits into coronoid fossa when elbow bends Styloid process – at distal end provides attachment for wrist ligaments

Wrist Wrist consists of carpals bound in 2 rows of 4 bones each Articulate with radius and ulna proximally and metacarpals distally Carpal bones are: Pisiform Triquetrum Lunate Scaphoid Hamate Capitate Trapezoid Trapezium She Left Town. Please Take The Cat Home

Metacarpals Form the palm of the hand 5 per hand Long bones with rounded distal ends (knuckles) Articulate with carpals and phalanges Lateral metacarpal is the most freely moveable Numbered 1-5, starting at the thumb

Phalanges Finger bones 3 per finger (proximal, middle, and distal) 2 in thumb – no middle phalanx

Bones of the Pelvic Girdle The total weight of the upper body rests on the pelvis It protects several organs Reproductive organs Urinary bladder Part of the large intestine

Coxal Bones Each coxa develops from 3 parts: Ilium Ishium Pubis Acetabulum – cup-shaped cavity where the 3 parts of coxa fuse, making the socket for the femur

Ilium Largest and most superior portion of the coxa Flares outward and forms the prominence of the hip Iliac crest – margin of the ilium Sacroiliac joint – where ilium and sacrum join Anterior superior iliac spine – found lateral to the groin, provides attachments for ligaments and muscles Posterior superior iliac spine – on posterior border

Ischium Forms lowest portion of the coxa L-shaped Ischial tuberosity – rough surface that points down and back; supports body weight when sitting Ischial spine – sharp projection above ischial tuberosity, near the junction between the ilium and the ischium Creates the narrowest part of the pelvis

Pubis Anterior portion of coxa Pubic symphysis – fibrocartilage joint between the 2 pubic bones Pubic arch – angle between pubic bones Obturator foramen – largest opening in the body Formed between ischium and pubis Covered and nearly closed by obturator membrane

Male vs. Female Pelvis Male Pelvis: Female Pelvis Heavier bone More evidence of muscle attachments Female Pelvis Iliac bones are more flared Broader hips Greater angle of pubic arch Greater distance between ischial spines and tuberosities Shorter, flatter sacral curvature More delicate bones

Lower Limb Bones Femur (2) Patella (2) Tibia (2) Fibula (2) Tarsals (7/foot) Metatarsals (5/foot) Phalanges (14/foot)

Total Knee Replacement Surgery

Femur Bone Features Thigh bone Longest bone in body Extends from hip to knee Head of femur – large and rounded; projects medially into acetabulum of coxal bone Greater trochanter and lesser trochanter – attachments for muscles of buttocks and lower limbs Lateral and medial condyles – articulate with tibia

Patella Articulates with the femur on distal anterior surface Kneecap Flat sesamoid bone located in a tendon that passes anteriorly over the knee

Tibia Bone Features Shin bone Larger of 2 leg bones; located on the medial side Medial and lateral condyles – on proximal end, articulate with condyles of femur Tibial tuberosity – below condyles on anterior surface; attachment of patellar ligament Anterior crest – extends downward from tuberosity; Medial malleolus – inner ankle

Fibula Bone Features Long, slender bone located on the lateral side of the tibia Articulates with the tibia just below the lateral condyle Lateral malleolus – distal end that forms the outer ankle

Bones of the Foot Tarsus – consists of 7 tarsal bones Talus – tarsal bone that can move freely where it joins the tibia and fibula Forms the ankle Other tarsals are bound firmly together to support the talus Calcaneus – largest tarsal bone; heel bone Located below the talus and projects backward Helps support weight of the body Cute Tilley Never Could Cooperate Cuddle or Cuss

Metatarsals Numbered 1-5 beginning on the medial side Ball of the foot formed by the distal ends If tissues that bind the metatarsals weaken fallen arches (flat feet) occurs

Phalanges Shorter, but otherwise similar to fingers 3 bones per toe, except 2 in the great toe