Appendicular Skeleton By: Dr. Holly Nash-Rule

Chapter 8, Bones, Part 2: The Appendicular Skeleton Everything that is not the Axial Skeleton, i.e., pelvis and limbs

The Girdles Supports the Arms Clavicle and Scapula Supports the Legs Pectoral Girdle Supports the Arms Clavicle and Scapula Pelvic Girdle Supports the Legs Pelvis Ilium, ischium, pubic bone Upper and lower limbs differ in function Share the same structural plan

The Appendicular Skeleton Pectoral girdle Attaches the upper limbs to the trunk Pelvic girdle Attaches the lower limbs to the trunk Upper and lower limbs differ in function Share the same structural plan

The Pectoral Girdle Consists of the clavicle and the scapula Medial end of each clavicle articulates with the manubrium and first rib Laterally—the ends of the clavicles join the scapulae Scapulae do not join each other nor do they articulate with the axial skeleton

The Pectoral Girdle Provides attachment for many muscles that move the upper limb Girdle is very light and upper limbs are mobile Only clavicle articulates with the axial skeleton Good for flexibility, bad for stability

Clavicles Extend horizontally across the superior thorax Acromial (lateral) end (b) Right clavicle, superior view Posterior Sternal (medial) Anterior Acromial end Sternal end Extend horizontally across the superior thorax Sternal end articulates with the manubrium Acromial end articulates with scapula

Clavicle (collarbone) Manubrium to Acromion Frequently fractured

Scapulae Lie on the dorsal surface of the rib cage Located between ribs 2–7 Have three borders Superior Medial (vertebral) Lateral (axillary)

Structures of the Scapula Acromion Superior border Lateral border Medial border (a) Right scapula, anterior aspect Inferior angle

Structures of the Scapula Acromion Supraspinous fossa Spine Infraspinous fossa Lateral border Medial border (b) Right scapula, posterior aspect

Scapula (shoulder blade) Glenoid Spine Acromion Acromioclavicular joint Inferior and Superior Angles Origin of biceps brachii muscle: Coracoid Process Supraglenoid tubercle

The Upper Limb 30 bones form each upper limb Grouped into the: Upper Arm = Brachium Forearm = Antebrachium Humerus, Radius and Ulna Wrist = Carpus Hand = Manus

Arm Region of the upper limb between the shoulder and elbow Humerus The only bone of the arm Longest and strongest bone of the upper limb Articulates with the scapula at the shoulder Articulates with the radius and ulna at the elbow

Humerus Head Greater and Lesser Tubercles Intertubercular Sulcus Biceps tendon Coronoid Fossa Olecranon Fossa Trochlea Medial and Lateral Epicondyles

Structures of the Humerus of the Right Arm Radial fossa Head of humerus Anatomical neck Deltoid tuberosity Coronoid fossa Medial epicondyle Trochlea (a) Anterior view Olecranon fossa Surgical neck Lateral epicondyle (b) Posterior view

Structures of the Humerus of the Right Arm Olecranon fossa Medial epicondyle Olecranon process Lateral epicondyle Medial epicondyle Head of radius Trochlea Coronoid process of ulna Head Neck Radial notch Radius Ulna Ulna Radius (c) Anterior view at the elbow region (d) Posterior view of extended elbow

Forearm Formed from the radius and ulna Proximal ends articulate with the humerus Distal ends articulate with carpals Radius and ulna articulate with each other At the proximal and distal radioulnar joints In anatomical position; the radius is lateral and the ulna is medial

Ulna Main bone responsible for forming the elbow joint with the humerus Hinge joint allows forearm to bend on arm Distal end is separated from carpals by fibrocartilage

Ulna Olecranon Trochlear notch Coronoid Process Ulnar Styloid Process Interosseous Membrane (between radius and ulna) Note how the two bones can cross

Proximal Part of the Ulna Olecranon process Radial notch of the ulna Olecranon process Head of radius Head Trochlear notch Neck Neck of radius Radial tuberosity Coronoid process Interosseous membrane Interosseous membrane Ulna Ulna Radius Ulnar notch of the radius Ulnar notch of the radius Radius Head of ulna Head of ulna Styloid process of radius Styloid process of ulna Styloid process of radius (a) Anterior view (b) Posterior view

Radius and Ulna Olecranon process View Trochlear notch Coronoid process Radial notch (c) Proximal portion of ulna, lateral view Ulnar notch of radius Articulation for lunate Articulation for scaphoid Styloid process View Head of ulna Styloid process (d) Distal ends of the radius and ulna at the wrist

Radius The head of the radius articulates medially with the radial notch of the ulna Contributes heavily to the wrist joint Distal radius articulates with carpal bones When radius moves, the hand moves with it

Radius Head, neck, shaft Insertion of biceps brachii Radial Tuberosity Radial Styloid Process Interosseous Membrane (between radius and ulna) Note how the two bones can cross

Distal Ends of the Radius and Ulna Humerus Humerus Olecranon fossa Medial epicondyle Olecranon process Lateral epicondyle Medial epicondyle Head of radius Trochlea Coronoid process of ulna Head Radial tuberosity Neck Radial notch Radius Ulna Ulna Radius (c) Anterior view at the elbow region (d) Posterior view of extended elbow

Styloid process of radius Head of ulna Styloid process of ulna (a) Normal position

Wrist and Hand Includes the following bones Carpus—wrist Metacarpals—palm Phalanges—fingers

Carpus = wrist Forms the true wrist—the proximal region of the hand Gliding movements occur between carpals Composed of eight marble-sized bones Carpal bones Are arranged in two irregular rows

Carpus (wrist) Four Proximal Four Pretty Skunks Long To Perform Scaphoid, Lunate, Triquetrum, Pisiform Four Pretty Skunks Long To Perform Four Distal Trapezium, Trapezoid, Capitate, Hamate Four Detailed Turtles Tailor Custom Hats

Figure 8.6a Bones of the hand. Phalanges Distal Middle Proximal Sesamoid bones Carpals 4 3 2 5 1 Hamate Carpals Capitate Trapezium Pisiform Trapezoid Triquetrum Scaphoid Lunate Ulna Radius (a) Anterior view of right hand

Manus (hand) - Metacarpus Five metacarpals radiate distally from the wrist forming the palm Numbered 1–5, beginning with the pollex (thumb) Articulate proximally with the distal row of carpals Articulate distally with the proximal phalanges

Manus (hand) – Phalanges Five phalanges radiate distally from the metacarpals forming the fingers Numbered 1–5, beginning with the pollex (thumb) Articulate proximally with the metacarpals Either articulate distally with middle or distal phalanges, Or don’t articulate distally

Manus (hand) – Phalanges con’t Pollex has two phalanges Proximal and distal All other fingers have three phalanges Proximal Middle Distal

Superior Bones of the Appendicular Skeleton

Superior Bones of the Appendicular Skeleton

Superior Bones of the Appendicular Skeleton

Pelvic Girdle Attaches lower limbs to the spine Supports visceral organs Attaches to the axial skeleton by strong ligaments Acetabulum is a deep cup that holds the head of the femur Lower limbs have less freedom of movement Are more stable than the arm

Pelvic Girdle Consists of paired hip bones (coxal bones) Hip bones unite anteriorly with each other Articulates posteriorly with the sacrum A deep, basin-like structure Formed by articulation of the coxal bones with the sacrum, and coccyx

The Pelvic Girdle Consists of three separate bones in childhood Ilium, ischium, and pubis Bones fuse, but retain separate names to regions of the coxal bones Ilium Large, flaring bone Forms the superior region of the coxal bone Articulation with the sacrum forms sacroiliac joint

The Pelvic Girdle Anterior and posterior iliac spines meet to form the iliac crest Greater and Lesser Sciatic Notches Ischial Tuberosity Acetabulum Acetabular fossa

Bones of the Pelvic Girdle Base of sacrum Iliac crest Sacroiliac joint Iliac fossa llium Coxal bone (hip bone) Sacrum Pubis Coccyx Pelvic brim Acetabulum Ischium Pubic crest Pubic symphysis (a) Pelvic girdle Pubic arch

Lateral and Medial Views of the Hip Bone Ilium Ilium Iliac fossa Iliac crest Iliac crest Body of the ilium Acetabulum Ischial body Ischial spine Ischial spine Pubic body Articular surface of pubis (at pubic symphysis) Ischium Pubis Ischium Ilium Ischium Pubis (b) Lateral view, right hip bone (c) Medial view, right hip bone

More Pelvis Articular Surface for Articulation with Sacrum Pelvic (or pubic) symphysis Fibrocartilage Stretches at childbirth Difference between male and female

True and False Pelves Bony pelvis divided into two regions False (greater) pelvis - bounde by iliac bones True (lesser) pelvis—inferior to pelvic brim Forms a bowl containing the pelvic organs Anterior abdominal wall False pelvis Pelvic brim, defining pelvic inlet True pelvis Symphyseal surface Coccyx Plane of pelvic outlet (b) True and false pelves

Female and Male Pelves

Female and Male Pelves

The Lower Limb Carries the entire weight of the erect body Bones of lower limb are thicker and stronger than those of upper limb Divided into four segments Thigh, leg, ankle and foot

The leg AKA Lower Limb Femur Patella Tibia/fibula Tarsus Foot

Thigh The region of the lower limb between the hip and the knee Femur—the single bone of the thigh Longest and strongest bone of the body Ball-shaped head articulates with the acetabulum Head and fovea capitus Articulate with pelvis Neck

Thigh The region of the lower limb between the hip and the knee Femur—the single bone of the thigh Greater and Lesser Trochanters Shaft Lateral and medial condyles and epicondyles Intercondylar fossa Patellar Surface

Femur

Structures of the Femur Neck Greater trochanter Lateral epicondyle Head Medial condyle Medial Anterior view Posterior view Patellar surface The lower limb between the hip and the knee Femur—the single bone of the thigh Longest and strongest bone of the body Ball-shaped head articulates with the acetabulum

Patella Triangular bone Imbedded in the tendon that secures the quadriceps muscles Protects the knee anteriorly Improves leverage of the thigh muscles across the knee

Leg Lower limb between the knee and the ankle Composed of the tibia and fibula Tibia (shin) — more massive medial bone of the leg Articulates with femur at superior end Forms the knee joint Articulates with talus at the inferior end Forms the ankle joint Fibula — stick-like lateral bone of the leg Does not contribute to the knee joint Stabilizes the ankle joint

Structures of the Tibia and Fibula

Figure 8.11a The tibia and fibula of the right leg. Articular surface of lateral condyle Interosseous membrane Fibular notch Fibula Head of fibula Posterior view Tibia of medial condyle Medial condyle Medial condyle Interosseous membrane Lateral condyle Fibula Head Anterior view Tibia

The Ankle and Foot Important functions Supports body weight Acts as a lever to propel body forward when walking Segmentation makes foot pliable and adapted to uneven ground

The Ankle and Foot Includes the following bones Tarsus – ankle Metatarsus – sole Phalanges – toes

Tarsus Makes up the posterior half of the foot Contains seven bones called tarsals Body weight is primarily borne by two bones: the talus and calcaneus

Callus Tillie Never Could Cooperate Tarsus Seven bones Calcaneous, Talus, Navicular, Cuboid, Cuneforms Callus Tillie Never Could Cooperate

Pedus (foot) – Metatarsus Five metatarsals radiate distally from the ankle forming the sole Numbered 1–5, beginning with the hallux (big toe) Articulate proximally with the tarsals Articulate distally with the proximal phalanges

Pedus (foot) – Phalanges Five phalanges radiate distally from the metatarsals forming the toes Numbered 1–5, beginning with the hallux (big toe) Articulate proximally with the metatarsals Either articulate distally with middle or distal phalanges, Or don’t articulate distally

Pedus (foot) – Phalanges halluxhas two phalanges Proximal and distal All other toes have three phalanges Proximal Middle Distal

Bones of the Foot Phalanges Distal Middle Proximal 1 2 3 4 Metatarsals 5 Medial cuneiform Intermediate cuneiform Lateral cuneiform Navicular Cuboid Tarsals Talus Trochlea of talus Calcaneus (a) Superior view

Arches of the Foot Foot has three important arches Medial longitudinal arch Lateral longitudinal arch Transverse arch Arches are maintained by Interlocking shapes of the tarsals Ligaments and tendons “Keystones” of arches Talus—medial longitudinal arch Cuboid—lateral longitudinal arch

Arches of the Foot Medial longitudinal arch Transverse arch Lateral (a) Lateral aspect of right foot

Inferior Bones of the Appendicular Skeleton

Inferior Bones of the Appendicular Skeleton

Inferior Bones of the Appendicular Skeleton

Inferior Bones of the Appendicular Skeleton

Hip fracture “Grandma fell and broke her hip.” More accurately, “Grandma broke her femoral neck and then fell.” Sometimes the fracture is at the intertrochanteric line